KR20010106445A - Stacked-carrier discrete multiple tone communication technology - Google Patents

Abstract

In a frequency domain spreading system " stack carrier " spread spectrum communication system 10, a superimposed or stacked complex sine carrier wave is multiplied by the time domain representation of the baseband signal. In a preferred embodiment 10, spreading energizes a large and fast Fourier transform (FFT). This reduces the complexity of the calculation for the FFT size of the appropriate output. Point-to-multipoint and multipoint-to-multipoint (nodless) network topologies are possible. The code nulling method is for interference cancellation and enhanced signal segmentation by utilizing the spectral diversity of the various sources 11. The basic system 10 can be extended to include multi-element antenna array 26/18 nulling methods as well as for interference cancellation and enhanced signal partitioning using spatial partitioning. Such a method allows for a directional and reverse transmission system that can be adapted or applied to a wireless environment. Such systems are suitable for bandwidth requirements and higher-order modulation formats and use advanced (maximum-SINR) despreader adaptive algorithms.

Description

STACKED-CARRIER DISCRETE MULTIPLE TONE COMMUNICATION TECHNOLOGY}

During World War II, communication technology developed along with "frequency diversity" or "stack carrier communication" for high frequency (HF) band calls. Reference may be made to the frequency diversity communication techniques described in Sections 7.4 to 7.7 of Digital Communications (McGraw-Hill Publishers, 1989) by J. Proakis. According to Proakis, diversity technology is based on the concept that errors are introduced when receiving a significantly attenuated channel, for example, a channel with a deep fade. For channels that only fade independently of each other, supplying the receiver with several replicated signals of the original signal has the potential for stable and continuous communication, except in the special case where all of the replicated channels fade out together. Such probability can be estimated.

Frequency diversity is one of many diversity methods. Nominally, the same modulation is achieved by several carrier channels divided by the bandwidth of each coherence channel. In time diversity, the same information is transmitted over different time slots. Multiple antennas may be used in the diversity configuration. Several receive antennas may be used to receive signals sent from one transmit antenna. It is most effective that the receiving antennas are far enough apart to change different multipath interference among the groups. In general, identifying independent signal fading requires separation of nominally 10 wavelengths.

Signals with bandwidths much larger than the coherence bandwidth of the channel can be used for more sophisticated diversity configurations. A signal with such a bandwidth W will resolve the multipath component and provide several independently fading signal paths to the receiver.

Another conventional diversity scheme was angle-of-arrival or spatial diversity and polarization diversity.

If a user can use a bandwidth (W) that is significantly greater than the coherence bandwidth corresponding to each channel, the channels are at least multiple frequency division multiple subchannels away from each other at the center frequency of the coherence bandwidth of each channel. Can be subdivided into The same signal can then be transmitted over frequency division multiple subchannels to establish frequency diversity operation. The same result can be obtained by using a wideband binary signal including the bandwidth (W).

GK Kaleh's paper, "Frequency-Diversity Spread-Spectrum Communication System to Counter Band-limited Gaussian Interference" (IEEE Transactions on Communications, September 1994), outlines a robust configuration that can operate in a modestly disturbed signaling environment. .

J. Proakis discusses the concept of frequency diversity spread spectrum and multiple access in Chapter 8, "Spread Spectrum Signals for Digital Communication." Diversity transmission combined with frequency hopping spread spectrum is detailed to prevent multipath fading and subband jamming.

An anti-directional method was proposed, which adopted a multi-element antenna array in the intention of providing the same spatial gain pattern in the transmission and reception operations, and was used in 1959 (discussion of such a technique by R. Monzingo, T. Miller, Introduction to Adaptive Arrays, Wiley Interscience Publishing, 1980; US Patent No. 2,908,002 to Van Atta, "Electromagnetic Reflection"; and US Patent No. 4,383,332 to B. Glance, P. Henry, filed May 10, 1983, "High. Capacity Mobile Radio System ". The TDD system provides an effective means of implementing a reverse antenna arrangement, for example, by minimizing channel changes between the receive and transmit paths.

TECHNICAL FIELD The present invention generally relates to wireless communication, and more particularly, to a communication technology for multiple access in an environment in which communication is difficult and disturbed due to dynamic environmental changes.

1 is a block diagram of a communication system embodiment of the present invention in which several remote mobile units are distributed in space around one or more central base stations.

2a shows an embodiment of the invention in which a stack carrier spread spectrum transmitter bank is connected to an antenna arrangement for a point-to-point transmitter, and another antenna arrangement is connected to a stack carrier spread spectrum receiver bank 5 for a point-to-point receiver. A block diagram showing an example.

2B is a block diagram illustrating an embodiment of the invention in which a stack carrier multiple access transmitter bank is connected to an antenna array for a network transmitter, and another antenna array is connected to a stack carrier multiple access receiver bank for a network receiver.

3A illustrates an embodiment of the invention in which a stack carrier spread spectrum transmitter bank is connected to a time division duplexer for a point-to-point transmitter, and another time division duplexer is connected to a stack carrier spread spectrum receiver for a point-to-point receiver. A block diagram is shown.

3B is a block diagram illustrating an embodiment of the invention in which a stack carrier multiple access transmitter is connected to a time division duplexer for a network transmitter, and another time division duplexer is connected to a stack carrier multiple access receiver for a network receiver.

4A illustrates an embodiment of the invention in which a stack carrier spread spectrum transmitter is connected to a code nuller for a point-to-point transmitter and another code nuller is connected to a stack carrier spread spectrum receiver for a point-to-point receiver. A block diagram is shown.

4B is a block diagram illustrating an embodiment of the invention in which a stack carrier multiple access transmitter is coupled to a code nuller for a network transmitter, and another code nuller is coupled to a stack carrier multiple access receiver for a network receiver.

5A shows a stack carrier spread spectrum transmitter connected to a widely distributed frequency channelizer for a point-to-point transmitter, and another widely distributed frequency channelizer connected to a stack carrier spread spectrum receiver for a point-to-point receiver. A block diagram illustrating an embodiment of the invention.

5B is a block diagram illustrating an embodiment of the present invention in which a stack carrier multiple access transmitter is connected to a widely distributed frequency channelizer for a network transmitter, and another widely distributed frequency channel riser is connected to a stack carrier multiple access receiver for a network receiver. It is also.

FIG. 6A illustrates a synchronization in which a stack carrier spread spectrum transmitter bank is connected to both a stack carrier spread spectrum receiver bank and an antenna arrangement having a retro-adaptor controlling the stack carrier spread spectrum transmitter bank for a point-to-point transceiver system. A block diagram illustrating an embodiment of the invention coupled to a time division duplexer bank.

FIG. 6B illustrates an embodiment of the invention in which a stack carrier multiple access transmitter bank is coupled to a synchronous time division duplexer connected to both an antenna array and a stack carrier multiple access receiver bank having an inverse adapter for controlling the stack carrier multiple access transmitter bank for a network system. A block diagram showing an example.

FIG. 7A is a functional block diagram of a stack carrier spread spectrum transmitter similar to those shown in FIGS. 2A, 3A, 4A, 5A, and 6A.

FIG. 7B is a functional block diagram of a stack carrier spread spectrum receiver similar to those shown in FIGS. 2A, 3A, 4A, 5A, and 6A.

FIG. 8 is a block diagram of a base station shown in the system of FIG. 1, illustrating the possibility of an antenna arrangement to spatially identify members of a communication system. Each functional transmitter and receiver line represents a number of channels that support the underlying stack carrier spread spectrum communication medium.

FIG. 9 is a block diagram of a typical remote unit shown in the system of FIG. 1, illustrating adaptive channel leveling and preemphasis functions supporting a basic stack carrier spread spectrum communication medium.

10 is a block diagram of a multi-element T / R module including a plurality of individual T / R modules, one for each antenna. System complexity can be large or small depending on the number of antennas. The spatial process takes place after the analog-to-digital conversion (ADC) processing in the receive operation and before the digital-to-analog conversion (DAC) operation in the transmission operation. In addition to spreading the spectrum, all space is performed with digital data. All key frequencies and reference clocks in the system are derived from common clocks such as GPS clocks. A mechanism for module calculation that requires accurate reverse orientation in a TDD system is shown.

11 is a block diagram of a stack carrier spread spectrum modulator superimposed over a K _spread split spread cell multiplied by a split scalar passed to base-time multiplexers for combination of complex data vectors.

12 is a block diagram of a stack carrier spread spectrum spreader in an all-digital fully adaptive implementation.

FIG. 13 shows an exemplary BPSK multi-tone with a data length of 6, a spread factor (K _spread ) of 4, and a separation between each group of 2. FIG. Each group cell g1-g4 is shown as having an independent amplitude that can be manipulated by channel equalization and preemphasis to solve interference and other problems.

14 is a diagram illustrating a "SCORE" processor used to recover a signal {x (t)} received from an antenna array. Processor control includes control filter {h (t)}, frequency-shift value alpha and conjugation control {(*)}.

15 is a data flow diagram illustrating a code gated SCORE spreading operation gating over two subsets of cells.

FIG. 16 is a data flow diagram illustrating a code gated SCORE spreading operation gating over two subsets of cells, showing that it is symmetric with that of FIG. 15.

17 illustrates a time-frequency format for a time division redundancy communication system, which is an embodiment of the invention.

18 shows an active tone format of a basic DMT modem.

19 is a data flowchart showing a transmission / reception calibration method.

20 illustrates an integrated single antenna (T / R) and discrete multiple tone (DMT) modem for using DMT based stack carrier multiple access (SCMA) according to an embodiment of the present invention.

21 is a general illustration of a single link code gated cross-SCORE spreader that is an embodiment of the invention.

22 is a data flow diagram illustrating a single link code gated cross-SCORE spreading operation with a subset of K _spread cells.

23 is a data flow diagram illustrating a single link cross-SCORE algorithm with N _frame packet / adapt frames.

24 is a data flow diagram illustrating a single adapter frame autocorrelation statistical calculation.

25 is a data flow diagram illustrating a cross-SCORE eigenequation with a K _spread cell subset.

Fig. 26 is a data flow diagram illustrating a code key generator having a cell subset with K _part < K _spread .

27 is a data flow diagram illustrating an equivalent code key applicator with a K _part K _spread cell subset.

28 is a data flow diagram illustrating a cross-SCORE eigenequation with a K _part subset.

29 is a data flow diagram illustrating a cross-SCORE eigenequation with two cell subsets.

30 is a data flow diagram illustrating a multilink code gated cross-SCORE spreader as an embodiment of the invention.

FIG. 31 is a data flow diagram illustrating a single link code gated auto-SCORE spreading operation with a gating over frequency and two cell subsets in an embodiment of the present invention.

32 is a data flow diagram illustrating a single link code gated auto-SCORE spreading operation with a gating over frequency and two cell subsets.

33 is a data flow diagram illustrating an auto-SCORE eigenequation with gating over frequency and two cell subsets.

34 is a data flow diagram illustrating single link code gated auto-SCORE spreading with gating over time and half speed of excess gate.

35 is a data flow diagram illustrating single link code gated auto-SCORE spreading with gating over time and half speed of excess gate.

Accordingly, an object of the present invention is to provide a wireless communication system that spreads data over a wide separated frequency band where the difference in channel distortion is apparent without physically spreading a signal between intervening frequencies where a direct-sequence spread spectrum is required. It is.

It is yet another object of the present invention to provide a wireless communication system by turning off a frequency channel affected by a communication under strong narrowband interference, e.g. a conventional cellular signal waveform at a receiver's despreader.

It is an object of the present invention to provide simple equalization of linear channel multipath distortion in a wireless communication system.

It is an object of the present invention to provide a wireless communication system suitable for discrete multi-tone and orthogonal frequency division multiplexing channelization techniques. It is also suitable for time packetized discrete multiple tones and orthogonal frequency division multiplex modulation / demodulation techniques for frequency channelization and dechannelization.

Another object of the present invention is a stack carrier spread spectrum modulation format in which a stack carrier spread spectrum signal is generated using, for example, discrete multi-tone and / or orthogonal frequency division multiplexing frequency channelization and dechannelization devices. The present invention provides a wireless communication system suitable for the packetized time division duplication system.

An object of the present invention is to provide a wireless communication system for frequency division multiple access type multiple access performance.

It is an object of the present invention to provide a wireless communication system for code division multiple access performance in a stack carrier multiple access configuration.

It is an object of the present invention to provide a wireless communication system suitable for higher order digital modulation.

It is an object of the present invention to provide a wireless communication system for bandwidth demanding flexible data rate connection.

An object of the present invention is to provide a wireless communication system for spatial division multiple access multiple access, interference cancellation and channel leveling performance in a code nulling application.

SUMMARY OF THE INVENTION An object of the present invention is to provide a wireless communication system for an adaptive antenna arrangement for distributing data using independent composite gain in each spatial channel or antenna beam to control channel bandwidth array dispersion by spatially extended dispersion codes. will be.

It is an object of the present invention to provide an advanced array application technique such as non-blind pilot-directed, blind data directed and the basic characteristics of baseband data, channel structure or stack carrier spreading format. It is to provide a wireless communication system suitable for other technologies that take advantage of the advantages.

An object of the present invention is to provide a wireless communication system suitable for reverse communication technology.

An object of the present invention is to provide a wireless communication system for back-compatibility in a conventional code division multiple access, data activation system.

In sum, embodiments of the present invention provide a "stack carrier" spread spectrum communication system spread in the frequency domain by multiplying the time domain representation of the baseband signal by a series of overlapping or stacked, complex sinusoidal carrier wavelengths. It includes. In practice, spreading occurs simply by energizing the bins of a large Fast Fourier Transform (FFT). This greatly simplifies the computational complexity for the proper output FFT size. For example, a Kaiser-Bessel window with β = 9 is used for these to "fill out" the space between the tones without being disturbed by adjacent tones such as, for example, inter-tone interference. do. In particular, a large value β allows for interference between adjacent tones and extremely low interference between the outer tones. This basic technique is thus combined with time division redundancy, code division multiple access, space division multiple access, frequency division multiple access, adaptive antenna array and interference cancellation techniques.

An advantage of the present invention is that a wireless communication method is provided that spreads data over a wide spread frequency band for spectrum diversity. This provides a way to efficiently take advantage of frequency diversity, especially in applications where the band is very widely separated.

An advantage of the present invention is that a wireless communication method is provided that communicates even under strong narrowband interference. Thus, a Stack Carrier Spread Spectrum (SCSS) link can be maintained in the presence of strong narrowband frequency division multiple access (FDMA) and time division multiple access (TDMA) cellular radio signals as in cellular overlay applications. It also allows such links to be maintained in the presence of pseudo interference due to harmonics from out of band signals.

An advantage of the present invention is that a wireless communication method is provided that allows simple equalization of linear channel distortion and approximates fixed or quasi-static linear channel distortion as a result of doubling on a transmission spreading code. This also allows channel leveling operations to be included in the despreading or spreading operation without additional filtering, independent of the elimination of intrapacket Doppler spreading. The underlying technique equalizes multipath dispersion to the bandwidth of the baseband, pre-spread, and message signals. If the bandwidth of the message signal is low, this multipath leveling can be extremely simple. If the bandwidth of the prespread message signal is low enough, for example, if the correlation width or inverse bandwidth of the prespread message signal is a large multiple of the maximum multipath delay in the transmission channel, then this leveling operation is automatically applied to the adaptive despreading operation. It is reduced by the complex multiplication operation involved. This is in contrast to conventional CDMA systems that require secondary leveling work unless the correlation width of the spread signal is a large multiple of the maximum multipath delay in the transmission channel.

Another advantage of the present invention is that a wireless communication method suitable for discrete multi-tone and orthogonal frequency division multiplexing frequency channelization techniques is provided. This allows fixed and linear channel distortions to be modeled as a result of exactly doubling on the transmission spreading code.

An advantage of the present invention is that a wireless communication method suitable for time division redundancy system is provided. Thus, when the stack carrier spread spectrum modulation format is packetized, the stack carrier spread spectrum signal may be decomposed using, for example, orthogonal frequency division multiplexing based on discrete multi-tones and / or frequency channelization and de-channelization. If generated, a time division redundancy communication format may be used. Either side of the communication link allows for "local" estimation of the transmission channel, greatly simplifying the implementation of reverse transmission techniques, transmission channel leveling topologies, and channel preemphasis.

An advantage of the present invention is that a wireless communication method having a code division multiple access type of multiple access performance, for example, a stack carrier multiple access technology, is provided. A point-to-multipoint communication link is implemented by transmitting signals over the same subset of frequency channels using a linear set of mutually independent spreading gains (orthogonal or non-orthogonal) to separate the signals in the spreader. Since spreading codes are non-orthogonal, the greatest advantage of the present invention when used in conjunction with code nulling techniques is the use of non-orthogonal codes.

An advantage of the present invention is that a wireless communication method suitable for " required bandwidth " flexible data rate technology is provided. The data rate supplied on a given link is increased or decreased in small increments by sending an initial signal to a single user over multiple time, frequency, or stack carrier channels. Thus, as the data rate increases the use of multiple stack carrier channels, the data rate is adjusted without increasing the bandwidth.

An advantage of the present invention is that a wireless communication method suitable for higher order digital modulation is provided. This is suitable for any ( _Mary ) digital baseband modulation format and improves performance by transmitting a larger number of bits / symbols in each frequency channel. Reuse is improved and "load balancing" can also be achieved in a multi-cell network by varying the number of bits per symbol of each initial value.

An advantage of the present invention is that, for example, in a code nulling technique, a wireless communication method having space division multiple access, interference cancellation and channel leveling performance is provided. Such spatial division multiple access code nulling techniques, optimal and suboptimal linear interference cancellation and signal extraction techniques are useful for separating stack carrier spread spectrum signals in the spreader based on frequency diversity or spectral diversity of the signal. Thus, interference cancellation for in-cell-stacked-carrier spread spectrum signals is achieved, as well as the elimination of outer interference of the cell, for example, reusable additive performance. This makes the most efficient use of code nulling that is generally applicable to a wide range of spread formats. In particular, in such a case, once the spreading gain repeats all the basic message symbols, two performance improvements can be made to code nulling techniques developed to use the symbol modulation direct sequence spread spectrum format.

An advantage of the present invention is that a wireless communication method is provided that can be used with an adaptive antenna arrangement.

An advantage of the present invention is that it is suitable for advanced array application techniques and thus provides a wireless communication method for separating signals based on a combination of spatial diversity, frequency spectrum diversity, polarization diversity and spatial / spectrum / polarization diversity. Is the point.

An advantage of the present invention is that a wireless communication method suitable for reverse communication technology is provided. This allows spatial reversed technology to be applied to stack carrier spread spectrum systems with a single antenna or antenna array as is. It also allows the base station to focus on the most complex tasks in point-to-multipoint communication links while significantly reducing the cost of the overall system.

Another advantage is that a wireless communication method can be used that can be reversely used in conventional code division multiple access and data activation techniques.

After reading the following detailed description of the preferred embodiment shown in the various figures, it will be apparent to those skilled in the art the above and other objects and advantages of the present invention.

1 shows a communication system according to an embodiment of the present invention, which is generally indicated by reference numeral 10. The system 10 comprises a base station 11 of bidirectional wireless communication having a plurality of remote units 12 to 17. The location of remote units 12-17 in the periphery of base station 11 in FIG. 1 indicates that they are all different distances in three-dimensional space assuming all remote distances or one or more remotes at various points in time. The base station 11 has a multi-element antenna 18. Each remote unit 12-17 has corresponding antennas 19-24, all or some of which may have multi-element antennas such as antennas 21, 23 and 24, for example. Antennas 18-24 show alternatives selected from a range from a single physical antenna connected to a transceiver that exhibits differential spatial signal sensitivity, respectively, to an individual transmit / receive antenna and antenna arrangement. Furthermore, all or some of the antennas 18-24 may be polarization diverse. That is, some antennas 18 to 24 may be positive sensitive polarizations (eg, antenna 20), and some may be voice sensitive polarizations (eg, antenna 22). "Positive / negative" polarization response can be based on "horizontal / vertical" linear polarization, "clockwise / counterclockwise" circular polarization, "incline 45/135" polarization, and the like. The actual noise enters the system 10 equally in all directions and the sources of interference are generally defined by their signals arriving in a particular direction. Multipath signals between the base 11 and remote units 12-17 represent one form of interference that can cause channel fades and other problems.

The system 10 may include multipoint-to-multipoint and point-to-point network topologies as represented by a second base station 25 having a multielement antenna 26. Multipoint-to-multipoint networks are a superset of that shown in FIG. 1 and are useful for cell systems where adjacent cell interfaces need to be controlled. Each base or remote transceiver in the network may have any different number of antenna elements and spreading factors, for example, that can be spread over different numbers of frequency cells. Spatially limited interference may result from other stack carrier networks and cells in the network, or from other interferences, such as FDMA signals or jammers that will overlap, for example, on the network. Real noise can enter the system equally or differently in all directions, where "same" can mean isotropic noise.

The basic means of wireless communication in the system 10 is here called " stack carrier spread spectrum " (SCSS), where discrete multi-tones (DMTs) with substantial frequency diversity are assigned to the base station 11 and each remote unit 12. To 17) at the same time. One baseband data symbol is a spread spectrum modulated in each set of discrete multi-tone transmissions from a single unit 11-17. Accurate data recovery can be performed by a given receiver even if several individual channels carrying information in discrete tones are fading out or severely interfered.

The invention can also be expressed in various ways, for example through several combinations of the embodiments shown in FIGS. 2A-6B. Each of the main elements introduced in FIGS. 2A-6B are described in more detail later with respect to FIGS. 7-16. Each array of antennas may have any spatial arrangement that does not require, for example, the specific antenna geometry for that array to function correctly. Moreover, the antenna may be relocated to polarization as well as to space.

2A shows a point-to-point transmitter 30 that includes a stack carrier spread spectrum (SCSS) transmitter bank 32 coupled to a multi-element antenna array (AA) 34. Point-to-point receiver 36 includes a multi-element antenna array (AA) 38 coupled to a stack carrier spread spectrum (SCSS) receiver bank 40. Each antenna array includes a plurality of antennas spaced apart in a space for transmitting and receiving data. For example, adaptive antenna array processing, such as multiple spatially separated antenna transmissions and / or adaptive linear coupling, is not here or combined with stack carrier spreading and despreading in FIGS. 2B, 6A or 6B. The array adaptation process is involved in stack carrier spreading and despreading operations.

2B shows a network transmitter 42 including a stack carrier multiple access (SCMA) transmitter bank 44 connected to a multi-element antenna array (AA) 46. Network receiver bank 48 includes a multi-element antenna array (AA) 50 coupled to stack carrier multiple access (SCMA) receiver bank 52.

3A shows a point-to-point transmitter 54 that includes a stack carrier spread spectrum (SCSS) transmitter 56 coupled to a time division duplexer (TDD) 58. Point-to-point receiver 60 includes a time division duplexer 62 coupled to stack carrier spread spectrum (SCSS) receiver 64.

3B shows a network transmitter 66 that includes a stack carrier multiple access (SCMA) transmitter coupled to a time division duplexer (TDD) 70. Network receiver 72 includes a time division duplexer (TDD) 74 coupled to a stack carrier multiple access (SCMA) receiver 76.

4A shows a point-to-point transmitter 78 that includes a stack carrier spread spectrum (SCSS) transmitter 80 coupled to a code nuller 82. Point-to-point receiver 84 includes a code nuller 86 coupled to a stack carrier spread spectrum (SCSS) receiver 88.

4B illustrates a network transmitter 90 including a stack carrier multiple access (SCMA) transmitter 92 coupled to a code nuller 94. The network receiver 96 includes a code nuller 98 coupled to the stack carrier multiple access (SCMA) receiver 100.

5A shows a point-to-point transmitter 102 including a stack carrier spread spectrum (SCSS) transmitter 104 coupled to a widely separated frequency channelizer 106. Point-to-point receiver 108 includes a widely separated frequency channelizer 110 coupled to a wide stack carrier spread spectrum (SCSS) receiver 112.

5B illustrates a network transmitter 114 that includes a stack carrier multiple access (SCMA) transmitter 116 coupled to a widely separated frequency channelizer 118. Network receiver 120 includes a widely distributed frequency channelizer 122 coupled to stack carrier multiple access (SCMA) receiver 124.

FIG. 6A shows both a stack carrier spread spectrum (SCSS) receiver bank 134 and a multi-element antenna array (AA) 132 having an inverse adapter 136 that controls the stack carrier spread spectrum (SCSS) transmitter bank 128. A point-to-point transmit / receive system 126 including a stack carrier spread spectrum (SCSS) transmitter bank 128 coupled to a connected synchronous time division duplexer (TDD) bank 130.

FIG. 6B shows both the stack carrier multiple access (SCMA) receiver bank 146 and the multi-element antenna array (AA) 144 with reverse adapter 148 controlling the stack carrier multiple access (SCMA) transmitter bank 140. Represents a network system 138 comprising a stack carrier multiple access (SCMA) transmitter 140 coupled to a connected synchronous time division duplexer (TDD) 142.

FIG. 7A shows a stack carrier spread spectrum (SCSS) transmitter 150 similar to those shown in FIGS. 2A, 3A, 4A, 5A, and 6A. The SCSS transmitter 150 includes a digital-to-analogue converter (DAC) that converts input digital data into an analog signal for transmission. Analog information for transmission may be directly input without going through the DAC (152). Two or more channels (e.g., 1, ..., k) are included that each modulate the corresponding radio frequency carrier in an up-conversion process. For example, each rising conversion channel includes a quadrature (Q) mixer 156 and an in-phase (I) mixer 154 connected to a 90 ° phase shifter 158 and a local oscillator (LO) 160. do. The modulation information thus controls the amplitude of the in-phase and quadrature phases of the AM carrier radio frequency. Gain controlled pairs of amplifiers 162 and 164 independently adjust in-phase and quadrature phase amplitudes before recombining by summer 166. The bandpass filter (BPF) 168 removes signals outside the band that may interfere with adjacent channels. The final adder 170 combines the signals from all the channels, producing a transmitter output that will be coming into the antenna, for example. Diffusion gain generator 172 periodically emits a group of parallel outputs that control all gain controlled amplifiers 162 and 164 on all channels in a group. Each control signal for each gain controlled amplifier 162, 164 can be configured with a signal digital line for 1-bit on / off control, multi-bit parallel digital control for discrete gray-scale settings, or a continuously variable gain setting. It may also include analog control.

Obvious changes in the analog circuits shown in FIGS. 7A and 7B for transmitter 150 and receiver 180 are, for example, fully-digital transmultiplexers ("transmux") having discrete digital logic or having a digital signal processor. Is to use

A discrete multiple tone (DMT) method of orthogonal frequency division multiplexing (OFDM), which will be described later, which is a preferred alternative to the direct or transmux spreading and despreading approach, is illustrated in FIGS. 7A and 7B.

Referring to FIG. 7A, during operation of the transmitter 150, some spread gain outputs from the spread gain generator 172 received by a given receiver unit are more easily obtained than can be obtained using different spread gain outputs. Will exist. A wireless communication environment that intervenes between a transmitter and a receiver typically attenuates or interferes more than others for certain phases and frequencies. The wireless environment includes interchannel interference, additional inter-networks, intra-networks and jamming / overlay signals, which more easily interfere with spreading codes that cannot be removed at the receiver. Thus, the spread gain output has the ability to compensate for the effects of both intervening wireless communication environments, channel distortions and interchannel interference. The optimum spreading gain output that should be generated at any point in time can be defined in a formalized sequence over time or place, or adjusted according to the results obtained by making some measurements on communication quality, such as reverse channel data, for example. . Spreading codes compensate not only for channel distortion but also for interchannel interference.

FIG. 7B illustrates a stack carrier spread spectrum (SCSS) receiver 180 aborted with those included in FIGS. 2A, 3A, 4A, 5A, and 6A and complements the transmitter 150 shown in FIG. 7A. The SCSS receiver 180 accepts an analog signal from a splitter 181 which creates several parallel frequency separated channels. A typical channel is driven by bandpass filter 182, splitter 183, in-phase gain controlled amplifier 184, quadrature phase gain controlled amplifier 185, local oscillator 189 and phase shifter 188. And a pair of phase detectors 186, 187, and an analog-to-digital converter (ADC) 190 that combines all receiver channels back into a digital signal. Each down-conversion channel comprises a quadrature (Q) mixer 187 and an in-phase (I) mixer 186 connected to a 90 ° phase shifter 188 and a local oscillator (LO) 189. It is made to include. A despreading weight generator 191 is connected to control the individual in-phase and quadrature amplifiers 184 and 185 of each channel.

8 shows a base station 230. For "code-nulling", the spreading weight maximizes the signal-to-interference-and-noise ratio of the spread message sequence in the preferred embodiment, and spread gain is preferred. Attention is drawn to derive directivity and reverse orientation by paying attention to derivation from the locally applied spreading weights. Base station 230 is similar to base station 11 (FIG. 1) and includes an antenna arrangement 232, transmit / receive (T / R) front end (T / R) for directional wireless communication with a remote unit by beamforming. 234, frequency channel bank 236, data cell mapper 238, weighted algorithm generator 240, multiantenna multilink spreader 242, delay and Doppler predictor 243, delay and A Doppler equalizer bank 244 and a symbol decoder bank 246 that outputs several recovered baseband data channels, such as for example a trellis decoder.

Several output baseband data channels are connected to a symbol encoder bank 248, for example a trellis encoder. From there, the transmission is a delay and Doppler preemphasis bank 250, a multi-antenna multilink spreader 252, an antenna and frequency channel mapper 254, and a transmit / receive compensation bank connected to the transmit / receive compensation algorithm generator 256 ( 255, and an inverse frequency channelizer bank 257 coupled to the T / R front end 234. The transmit / receive packet trigger 258 receives GPS time transmission information to control the interleave and duration of individual transmit / receive times at the T / R front end 234. The base station may also have as few as one antenna element in its arrangement. In a preferred embodiment, the base station uses packetized time division redundancy (DMT) or OFDM modulators and demodulators to perform inverse frequency channelizer and frequency channelizer operations.

For more information on alternative use of trellis code modulation, see Boulle et al., "An Overview of Trellis Coded Modulation Research in COST 231 (IEEE PIMRC '94, pp. 105-109)." .

9 shows a preferred embodiment of the remote unit 260. The remote unit 260 is similar to the remote units 12 to 17 (FIG. 1), and includes an antenna arrangement 262 for transmission and reception (T / R) with a base station by a combination of spatial and spectral diversity. ) Front end 264, frequency channel bank 266, data cell mapper 268, weighted algorithm generator 270, multiantenna spreader 272, delay and Doppler predictor 273, delay and Doppler equalizer 274 And a symbol decoder 276 that outputs the recovered baseband data channel, such as, for example, a data decoder. Some or all of the antennas in antenna array 262 may or may not be polarized diverges (eg, antenna 263).

The output baseband data channel is coupled to a symbol encoder 278, for example a data encoder. Transmission also includes a transmit / receive compensation bank 285 that connects to a delay and Doppler preemphasis unit 280, a multiple antenna spreader 282, an antenna and frequency channel mapper 284, and a transmit / receive compensation algorithm generator 286. And an inverse frequency channelizer bank 287 coupled to the T / R front end 264. The transmit / receive packet trigger 288 accepts GPS time transmission information to control the interleaving and duration of individual transmit and receive times at the T / R front end 264.

The remote unit can have as few as one antenna element in its arrangement. The number of antennas in each remote unit may vary from unit to unit. This may change the cost of the remote unit based on the importance or data rate of the given unit. The remote unit can use different spreading rates. They can spread their data over different subsets of frequency channels used at base station transmitters. In a preferred embodiment, the remote unit uses packetized time division redundancy (DMT) or OFDM modulators and demodulators to perform inverse frequency channelizer and frequency channelizer operations. The difference between a base station and a remote unit is that the base station transceiver sends signals from multiple nodes, for example multiple access. Each remote unit sends and receives only a single data stream intended for it. Channel equalization techniques and code nulling are limited to how spreading and spreading weights are matched.

10 shows a multi-antenna transmit / receive module 290. The module 290 includes a multi-element antenna array 291, each element being connected to, for example, four corresponding single channel T / R modules 292. Each T / R module 292 is coupled to a packet trigger 293, a receiver calibration generator 294, a local oscillator 295 and a system clock 296. These are alternately driven by GPS clocks and Doppler calibration signals. Each T / R module 292 includes a T / R switch 297, an intermediate frequency (IF) down converter 298, an analog-to-digital converter (ADC) 299, and a digital-to-analog converter (DAC). ) 300, an IF rising converter 301, and a power amplifier (PA) 302. Receive weight information is known during reception and is used to set the relative transmit power applied to each antenna element, for example, to compensate for channel fades or interference. If the base station is a polarized diver, it is important that the transmit / receive module has to excite both polarizations separately.

Transmit and receive time slots are triggered at specific times that may be false randomly determined according to a source of accuracy independent of time universally accessible, for example, from the US Department of Defense managed GPS. Such GPS time is also used to derive the local oscillator and ADC / DAC clocks used in the system. The receiver side need not be synchronized to the remote source. In particular, the receiver system does not need to know the area, propagation delay and Doppler shift between the communicators before receiving the first data packet. However, some accuracy can be found in the range, speed, delay, and Doppler shifts between communicators for certain applications. It is not necessary to know the area, propagation delay and Doppler shift between the communicators before receiving the first data packet.

The calibration mode is optional and only used when a reference is needed. For example, it is used only when intermittent calibration of an initial or predetermined diagnosis result is required.

For example, the encoding, spreading and modulation operations shown in FIG. 11 are preferably reflected by similar demodulation, despreading and deencoding operations, for example, as shown in FIG. The data flow of FIG. 11 is symmetrical to that of FIG. 12. For example, as in FIG. 11 and FIG. 12, the data flow is the same, the adder in one view is expanded and replaced in another view. Such symmetry is illustrated by DMT modulators and demodulators, frequency mapping and inverse mapping operations, spreading and despreading operations, and code gated spreading and despreading operations. The structure of the spreader is the mirror structure and the structure of the spreader. Conventional CDMA transceiver technology does not have such symmetry. Thus, such symmetry is a critical feature in embodiments of the present invention.

11 shows a discrete multi-tone stack carrier spread spectrum (SCSS) modulator 300 for frequency channelization in an embodiment. The frame generation command from the navigation and coding system 302 causes the signal modulator 304 to encode ephemeris, position, velocity, acceleration, and other messages in the K _cell symbol data vector. These symbols are then used to modulate a set of fast Fourier transform (FFT) bins or baseband tones. In spreader 306, a K _cell baseband tone is superimposed on a K _spread split spreading cell, e. the processing gain is multiplied, the K _active complex data-conveys the time multiplexer combining the long cell vector _{(here, K active ≥K cell * K spread} ). The complex data vector is passed to a zero-pad inverse FFT operator 308 that directly converts the data vector into K _FFT ≥ (1 + SF) · K _active real IF time samples (where “SF” means “shape factor”). Or the ratio of stopband to passband for the system). Then, the first E _roll K _FFT sample in the time sequence is repeated to form a K _pachet = (1 + E _roll ) K _{FFT -long} data sequence. Multiplier 312 multiplies this by K _packet -long data to generate a final sampled signal from Kaiser-Bessel window 314. The sampled signal is then transmitted to a digital-to-analog converter, which results in a T _packet, K _packet / f _s long data burst, and is passed to the frequency upconverter and communication channel, where f _s is the complex sample rate of the DPS / DNC nodule. to be. The parameters used to reduce the characteristics of the transmitted signal are all comparable to the GPS time, so that nodes in the communication network are transmitted simultaneously. This is the process of repeating it for each antenna in the system.

Symbol encoding in baseband tones is included in baseline system 300. Each K _cell data bit modulates a separate tone in the signal baseband, so that the tone is zero or 180 [deg.] Phase modulated if the data bit modulating that tone is zero or one, respectively. Such tone modulation is very efficient with regard to allowable transmit power. It provides sensitivity to radiometric detection technology and gives confidence in the demodulation of the transmitted bit sequence at E _b / N ₀ as low as 3dB. The BPSK format enables a powerful and sophisticated method of removing time and carrier offsets from the spread signal when based on conjugated self-coherence of the tone phase sequence.

Such work is for each frequency cell k and antenna 1 used by the transceiver, for example a single antenna using a different complex spreading gain g _k1 . Prior to the digital-to-analog conversion operation (T _packet = (1 + e _roll ) T _FFT time delay after the DAC operation), the path must contain the packet expansion factor (e _roll ) and the packet sample length (K _packet = (1 + e _roll). ) K _FFT ) samples are used. The spreading gain g _k1 may be determined through the number of means based on the despreading weight w _kl , for example via codebook, random, false random or adaptability.

The number of information bits per data symbol is K _bits . BPSK is a simple encoding scheme when encoding is omitted and K _bit = 1. Platform celestial force, position, velocity, and acceleration information are examples of data that may be transmitted in some applications. BPSK is the preferred modulation for the application unless data rate is a top priority for the system.

Delay and Doppler preemphasis operations are optionally included in alternative embodiments. Doing so may be included to eliminate the effects of delay and Doppler shift in certain receivers of signals to be transmitted from the DMT modulator after initial packetization. This operation can simplify the design of the transceiver in the network, for example by allowing delay and Doppler removal operations to be concentrated in the base stations of the network.

As a generalization of the spreading concept for a multiple access transceiver, a separate set of spread gains g _k1 (m) can be used to spread the data symbols intended for user m in the multi-user transceiver.

12 shows all digital fully applicable spread and beamforming receivers 320. For a background of this technology, see Tsoulos et al., "Application of Adaptive Antenna Technology to Third Generation Mixed Cell Radio Architectures (March 1994, IEEE # 1-7803-1297, pp 615-619)." . If there is a frame receive command from the receiver navigation and coding system 322, the signal modulator 324 will collect a series of T _gate -long transmission frames from the K _array of the array antenna 326 and convert from analog to digital ( Where T _gate is the time delay spanned by the K _gate sample). This is included in the T _guard -long guard time slot due to an unknown propagation delay between the transmit and receive links (T _gate = T _packet + T _guard ), where T _gate is the time span of the packet and T _guard is the K _guard sample. Time span spanned by). The K _gate -long digitized data frame is output from each ADC and then passed to a window zero pad poor FFT 328 that transforms the packet into a frequency domain with each tone separated by an integer number of FFT bins.

The FFT bin removes unused FFT bins from the received data set and groups the remaining bins in the K _cell x (K _{spreadK array} ) data matrix containing the received tones over each transmitted spreading cell ( Where K _sptead is the frequency spread factor, K _cell is the number of symbols per pre-spread data cell, and K _array is the number of antennas). Each spread data cell passes through a bank of linear combiners 332 that eliminates cross channel interference covering each cell and despreads the original baseband symbol tones from the received data set. The combiner weight is adjusted to use a code-category self-coherence recovery method that spatially filters the frequency dependent multiple antenna reception and spread interest signals and simultaneously despreads the received data signal.

The combiner weight is used to build a set of transmission weights to be used for any subsequent return transmission. Such tones are then passed to a delay and Doppler equalization unit 334 that predicts and removes Doppler shifts (non-integer FFT empty shifts) and message propagation delays (phase matrices) from the received data set. The symbol demodulator 336 predicts the transmitted message symbol.

Thus, received data packets sent from each user are despread and extracted from the received interference environment. The processor does not require fine time / carrier concurrency at the transmitter until the baseband signal has been despread at a high signal-to-interference-and-noise ratio and there is still strong noise and cross-channel interference.

The K _cell symbols sent from user m are weighted for each K _cell tone received at frequency cell k and antenna 1 by the same complex despreading weight w _k1 (m) and the tone As cells are added together to the bi-tone basis, extracted from the channel at the receiver, the tone q in each received frequency cell is added to all of the K _spread K _array frequency cells and antennas used in the system.

Each multi-element transceiver preferably has a minimum number of spatial and spectral degrees of freedom (K _array · K _spread ) to successfully null any random-stack carrier interferer entering each frequency cell. Any excess residual freedom is used to enhance the SINR of the spread baseband signal or to separate the overlapping stack carrier signal. Next, the multielement spreader weights are adjusted to minimize the power of the spread baseband signal. This results in a coat nulling solution that is considerably more powerful than conventional despreading methods. An ideal spreader adjusts the spreader weights to null the non-stack-carrier interference sources to lower the noise floor over each frequency cell, while simultaneously enhancing the SINR of the spread signal. The multi-element spreader also more certainly has weak nulling for interference sources with weaker radio signals in certain frequency cells. Thus, a soft null may be done to the interferer received with a weaker force in a given frequency cell. For example, if the interferer spectrum has a particularly weak value at that frequency, weaker nulls can be done at the far edge of the interferer passband.

In general, the spreader weights including adaptive antenna arrangements significantly improve the quality and performance of signal transmission and reception operations. For the receiver side of the system, a blind or unbiased method can be used to shoot the beam closest to the optimum in the interest signal and to null the jamming signal at the same time.

In general, the spreading weights are adjusted to minimize the signal-to-interference-and-noise ratio (SINR) of the spread baseband signal, such as, for example, the predicted data symbols. This typically causes the set of code nulling despreading weights to be clearly different from the spreading gain used to despread the baseband signal at the other end of the link. In particular, such resulting spreading weights will simultaneously remove channel distortions such as select gain and fade due to multipath. Despreading optimizes the tradeoff between nulling interferences received by the transceiver by maximizing the signal-to-interference ratio and maximizing the signal-to-noise ratio (SNR) of the spreader. The despreading codes in conventional DSSS and CDMA systems are set up identically to the spreading codes at the other end of the link and merely maximize the SNR of the despread baseband signal.

In a preferred embodiment of the present invention such work is blindly performed, and transmission spread gain and channel distortion are unknown in the spreader. This simplifies the protocol used within the network by making it possible to use the gain without knowing the spread gain in the transceiver in the network. This also allows the use of a tightly determined spreading gain that is continuously optimized to mitigate the noise, interference and channel distortion encountered on the transmission path by the transceiver.

Such an approach upgrades a multi-element SCMA or SCSS transceiver using an antenna array without requiring any qualitative change in spreading, despreading or gain / weighting algorithms. The difference lies in the multielement transceiver in terms of multielement spreading and despreading operations. However, multi-element transceivers have better performance because of the greater degree of freedom that can be used to separate SCSS signals. The area and / or immunity deprived by radiometric detection means is increased because its capacity depends on the spatial beam to other communicators in the network. The ability to spatially null those signals even when they arrive from above the frequency range region also improves immunity to jamming from non-SCSS signals.

The rapid-convergence method, which functions on a single data packet, interferes with the need for calibration data arrangements or without knowing or predicting the direction-of-arrival of interest or interfering signals. It may be combined with a frequency channelized interest signal or processor structure to enable frequency selective nulling of the original signal. Thus, the system 10 (FIG. 1) can detect and demodulate data packets in a highly dynamic environment where the channel geometry varies significantly between packets. As such, the processor could operate in a typical overload environment where the number of interferers is less than the number of antennas in the receiver antenna array.

On the transmitter side of the system, an interference signal is returned to the source with the maximum power and / or the minimum transmitted radio signal (directional mode), or with it the element is returned back to the source with the maximum radiation in the direction of the interferer. Directional or reverse application may be used to shoot the interest signal (reverse direction mode).

Directional mode is useful in applications where compatibility with non-SCSS interferers is not a priority for operators or where interfering transmission and reception platforms are unlikely to be in the same location. This mode is also useful in applications where the communication platform is subject to severe non-SCSS interference where maximum power must be delivered to the other end of the communication link.

Even if the interferer completely covers the interest signal passband and packet spacing, it can shoot the maximum beam back to the other end of the communication link and accurately measure the received interest signal steering vector without any knowledge of the direction of the received signal arrival. A processor may be used. The system 10 (FIG. 1) delivers K _array factor greater power to the other end of the communication link providing additional immunity to any jamming in the system. This may be done even while the other end of the communication link is transmitting and receiving with a single antenna. In contrast, the system 10 (FIG. 1) may maintain a communication link using a low power K _array factor. This reduces the geographic area within which the system can be detected by the factors of the K _array .

The reverse orientation mode implemented with reverse adapters 136 and 148 in FIGS. 6A and 6B is useful in applications where the interceptor is in the same area with the interferer, for example to approach the effectiveness of the jamming strategy. .

13 illustrates a single frame digital multiple tone (DMT) modulation and spreading format 340. The format 340 is used for an exemplary environment where K _cell = 6 and K _spread = 4 and each spreading cell separated by two FFT bins and thus K _space = 2. The six data bits to be transmitted are sent first in a set of ± 1 data symbols. The symbol energizes six baseband FFT bins with separate complex weights (g _k ) in each cell, for example overlapping over four cells of an FFT bin, such as a spreading cell. The complex weights are spread gains and are set over each data packet either randomly or falsely. Spreading is done in the frequency domain by multiplying the time domain representation of the baseband signal by a set of overlapping or stacked complex sine carrier waves. In practice, spreading is done by simply energizing the bins of large FFTs, which remain significant in arithmetic complex numbers for a suitable output FFT size. A Kaiser Vessel window with β = 9 is used in the present invention to “fill out” the space between tones that are not subject to unacceptable interference from adjacent tones such as, for example, intertone interference. In particular, large values of β give acceptable interference between adjacent tones and extremely low interference between outer tones.

Non-blind or calibrated techniques use information about baseband data sequences or channel distortions and spreading gains to develop ideal weights based on optimal signal prediction (eg, least-squares). Blind or cross-referenced techniques use the more common characteristics of baseband data signals to match the spreading weights. Mixing these techniques using known and unknown components of the transmission channel and / or baseband signal can be used to build an effective solution. Examples of particularly useful blind techniques include constant coefficients, multiple coefficients and crystal orientation techniques. Those use the properties of the message symbol constellation to match the spreading weights. Many methods can be used to match the multielement spreader weights in the demodulator 332 (FIG. 12). First, there is a dominant-mode prediction (DMP) method that takes advantage of known packet arrival times or known spreading parameters of discrete multi-tone stack carrier signals. Second, Code-Gated Self-Coherence Restoration (SCORE) takes advantage of non-zero correlation between spectrally separated signal components in a known self-coherence or discrete multi-tone stack carrier signal. There is a way.

In these two basic categories, self-coherence recovery techniques have the greatest practicality for the detection of discrete multi-tone stack carrier signals and for single packet acquisition.

Conventional spectra and other forms of self coherence restoration take advantage of known spectral and / or conjugate self coherence properties. This is a nonzero correlation between the frequency shift and / or conjugate components of a given communication signal. The blind method does not require any prior knowledge of the content of interest signals or their direction of arrival. Instead, the blind method uses its own local information for a particular frequency shift that correlates with the interest signal. See B.Agee, S. Schell, W. Gardner, "Self-Coherence Restoral: A New Approach to Blind Adaptation of Antenna Arrays", (Proceeding of the Twenty-First Asilomar Conference on Signal, System and Computer, 1987). Can be. B. Agee, S. Schell, W. Gardner, "Self-Coherence Restoral: A New Approach to Blind Adaptive Singnal Extraction Using Antenna Arrays" (IEEE Proceedings, Vol. 78, No. 4, pp. 753-767, April 1990). See also B. Agee, "The Property Restoral Approach to Bilnd Adaptive Signal Extraction" (Ph.D., University of California, Davis, CA, 1989).

In a double side band amplitude modulated signal, the actual IF representation of such a signal has conjugate symmetry for both the DC due to the actual IF representation and the carrier frequency due to the double sideband amplitude modulated modulation format. This symmetry is set off to each other because of the positive and negative frequency components of the signal, which should be identical to each other. This perfect spectral self-coherence is observed by calculating the correlation coefficient between the double sideband amplitude modulated interest signal and its own copy which is frequency shifted with twice the carrier. The frequency shifted operator mixes the negative frequency components into the frequency bands filled with the positive frequency components due to the correlation coefficients that should have non-zero values. Such a nonzero value only occurs when the value of that frequency shift is applied to the replica. A unity correlation coefficient is obtained by filtering out an external radio signal that does not initially overlap the interest signal and a frequency shifted dual sideband amplitude modulated signal.

In FIG. 14, a cross self-coherence recovery (SCORE) processor 350 is used to perform recovery applied to the multi-antenna received data signal x (t). The processor 350 first transmits data received through a series of filtering, frequency shift, and selective conjugate operators to become a signal u (t) related only to a signal targeted by the processor. Then, the initial signal and the processed signal x (t) = u (t) are combined with the combiner output signals y (t) = w "x (t) and r (t) = c" u (t). Passed through a pair of beam-and-null steers (linear element combiners) 352 and 354 tailored to maximize the correlation coefficient between them. The control parameters used to target the processor are typically filter operators that are set to a delay operator, a frequency shift value α and a conjugation flag *. The processor parameters are set to values that yield, for example, a strong correlation coefficient without interference in the transmitted interest signal for the processor.

15 and 16 illustrate code gating operations used in a typical code-category SCORE operation. Certain code gating configurations require some importance changes to the spreader and spreader data flows and hence the structure. These show one way of enabling the code gated SCORE despreader adaptive algorithm shown in the figure. Another way is to apply code gating across a packet or inside a frequency cell without crossing the frequency cell. For example, by repeating a data symbol with a gating code applied to an across K _cell baseband symbol on the even packet, this results in no impact on the data flow through the spreader and the spreader.

Splitting spreading cells into K _part ≥2 subsets, K _SCORE cells / subsets -K _part = K _spread , cells processed in individual subsets, and K _SCORE = 1 cells / subsets

The same key code for all cells in each _part K and K _SCORE = K _spread and subsets in the case - -K _part = 2, Even and Odd subset of the separated cells, K _SCORE = K _spread / 2 cells / subset in -C (n; K _part / + K) = c (n; k), k = 0, ..., K _part -1, / = 0, ..., K _SCORE -1-Alternative Type: c (n; k) = c (n; (k) K _part ), k = 0, ..., K _spread -1, (k) K _part = k modulo-K _{part of} each subchannel K _array per transmit (subset coded) with multiple SCSS subchannels (stack-carrier multiple access) using different code keys with the same structure Allow separation of K _SCORE subchannels- greater data rate per user (Multiple subchannels per user) Enabled- Multi-access communication (multi-user communicating with the cell) possible-K _SCORE -1 Reject SCSS interference (cellular communication) possible-Require greater time bandwidth generation to achieve the same level of misalignment and in fact, adjusted for a specific application cases of K _part -SCSS ratio between The large, fast convergence time is an important cellular overlay systems, asynchronous, point-to-point links in the K _part = K _spread SCSS interference is greater SCMA systems, point-to-multipoint links in the K _part = 2

Code gated self coherence recovery takes advantage of self coherence that a communication system has been artificially added to facilitate adaptive spreaders but cannot be determined without access to gating information in the communication network. The present invention includes two code gated SCORE methods.

A preferred self-coherence recovery method for multiple access communication involves applying a unique code gating operation to the baseband message signal prior to the spreading operation, which is uniquely determined for each link of the system. For example, if the frequency cells are divided into two subsets, namely even and odd, the code key is applied only to the odd cells, as shown in Figs. The data symbols are spread over even cells using the method shown in FIG.

Similar spreading operations may be applied to the odd cells. However, in the data symbols transmitted to these cells, a code gating operation is first performed in which a different constant coefficient code key c (m) = [c ₄ (m)] is multiplied for each user m of the network. This operation is reversed in the multiple access spreader. After the despreading operation, before combining the outputs of the despreaders used on even and odd frequency cells, the odd frequency cells are multiplied by a pair of code keys (c ^* (m)). Code gating operations at a single-user SCSS transceiver are performed only for a single code key used at the SCSS transceiver. In operations that accept a single-packet, a spread (pair) codekey is applied on each received odd frequency cell and transceiver antenna prior to the linear combining operation.

The effect of the code gating operation is that the signal transmitted with the code key has a uniform correlation coefficient between even and odd frequency cells after multiplying the spread code key by the odd frequency cell. Conversely, the same code gating operation will cause all other signals transmitted using different code keys to have low correlation coefficients between the even and odd frequency cells. This condition will be maintained regardless of the (assuming unknown) delay and Doppler shift applied to the received signal. The resulting signal can then be input directly into the cross-SCORE algorithm shown in FIG. 14, where x (t) is replaced with an even (ungated) frequency cell and u (t) is an odd (gated) signal. ) Is replaced by a frequency cell, where t represents the symbol index (q = 1, ..., K _cell ), not the time index. The despreading weight is adopted such that the correlation coefficient between the outputs of the despread linear combiner applied to the even and odd frequency cells is maximized.

This method provides despreading and reliable detection of any link in the network based on only the code key known for the link. In a single-user SCSS transceiver, the transceiver only disperses the link in communication without the need for additional computation to acquire the link and verify that the correct signal is being delivered. If the link is temporarily lost due to adverse channel conditions, such as "port shuffling" that occurs in long transmissions, for example, it is automatically reacquired. For multi-user SCMA transceivers, this method applies to all links supported by the transceiver based only on known code keys used by nodes linked to the transceiver, without port swapping or shuffling of channel conditions. Enable reliable detection, despreading and identification The code key provides some privacy by scrambling included in the code-gating operation.

The basic code-gated SCORE method may be generalized in a number of ways. In particular, the codekeys may be used for not only odd but also odd frequencies in order to provide enhanced security and decoration between frequency cells. Can be applied. This code gating may be omitted at even packets, and may be applied at non-frequency times by sending data symbols on consecutive packets including code gating performed across all frequency cells in odd packets. If the spreading code remains constant across these packet pairs, this approach allows the use of a more powerful auto-SCORE method for adapting the spreading weights.

More robust algorithms allowed in certain environments-channel response approximated equally or nearly identical (different by scalar) on each spreading subset-equally approximated background interference on each spreading subset Possible predictor derivation-spreading gains applied equally or nearly equally on each spreading subset-spreading weights applied equally or nearly equally on each spreading subset-the basic mode of auto-SCORE eigen Set the spreading weights for the s), with the advantage of cross-SCORE eigenvalues-lower complexity-lower misalignment for the same time-bandwidth results-maximum-SINR on each subset in network applications Equal-no asymptotic misalignment · disadvantage-modeling error if channel response is not the same on each subset Sensitive to Difference-Timing and / or Doppler tracking / removal required during despreading operations (typically simple algorithms)

A large number of frequency or packet subsets may be used in the system by individually setting the code key employed in each subset. In this case, the spreader uses the general concept of the cross-SCORE method by super-vector analysis of the cross-SCORE eigenequation. B. Agee, "The Property-Restoral Approach to Blind Adaptive Signal Extraction," in Proc. 1989 CSI-ARO Workshop on Advanced Topics in Communications, May 1989, Ruidoso, NM; And B. Agee, "The Property Restoral Approach to Blind Adaptive Signal Extraction," Ph.D. See Dissertation, University of California, Davis, CA, June 1989. As the number of frequency subsets increases, the number of multiple access communications that can be supported by the transceiver decreases, but the stability of the weight calculation improves, and the unstacked carrier nulling capability and noise reduction of the algorithm remain unchanged. The limit of the number of frequency subsets is equal to the spreading factor K _spread .

The code-gated-self-coherence recovery method uses the basic mode of the multicell self-coherence recovery eigenequation, which is a signal-of-interest directly from the channelized data super-vector. interest) extract baseband. The method simultaneously performs frequency-dependent spatial filtering, couples the antenna elements in each cell to the spread signal-of-interrupt, and despreads the resulting data signal to combine into the frequency cell.

The code-gated-self-coherence recovery method can effectively compute at positive or negative received SINR if the beam-forming SINR of the maximum achievable spread and received data packet is positive. This method adapts to the antenna arrangement as a unique element of the spreading (linear combination) operator. The same method is used for any number of antennas, including a single antenna system with K _array = 1. The code-gated-self-coherence method does not require spread knowledge at any point in time or prior knowledge of the basic message sequence in its implementation. This method does not require investigation of time or Doppler shifted frequencies to despread the message sequence.

The default eigenvalues of the code-gated-self-coherence recovery eigenvalues provide new signal packet detection when the communication link is first opened. The receiver functions on an "on-demand" principle, returning the pulse to the other end when the packet is transmitted in the communication channel.

An additional method enhances or confirms detection for discrete multi-tone stack carrier data packets after code-gateed-self-coherence recovery. In particular, detection reliability is further improved by using less eigenvalues of the code-gated-self-coherence recovery eigenvalues to predict the mean and standard deviation of the maximum code-gated-self-coherent recovery eigenvalues. Can be improved. The maximum eigenvalue is then reduced by the predicted mean and proportional to the expected standard deviation, resulting in a more powerful trend corrected detection statistic.

Another method uses downstream de-spreading and demodulation operators to support packet detection in code-gateed-self-coherence recovery.

In initial Doppler recovery upon acquisition of the first data packet, the first data packet is extracted in the full remode of the receiving side FFT, and a linear interpolation method is used to subtract the resulting output signal for the transmitting side frequency remode. Use frequency-domain analogs of equally spaced equalizers by sampling. Linear combination weights resample the data to tune the center using any appropriately adopted method. Least-squares feature reconstruction algorithms, such as the constant coefficient method, minimize the variation of the coefficients of the spread data symbols. Least-squared constant coefficients use the property that transmitted data tones have a constant coefficient if they are generated using BPSK modulation, but if a Doppler shift occurs that is a non-integer multiple of tone spacing in the transmitted signal, Destroyed. This least-squares constant coefficient stores this characteristic in the spreader output signal. The overall technique works under significant Doppler shifts and path delays. B. Agee, "The Least-Squares CMA: A New Approach to Rapid Correction of Constant Modulus Signals," in Proc. 1986, International Conference on Acoustics, Speech and Signal Processing, Vol. 2, pg. 19.2.1, April 1986, Tokyo, Japan. See.

Two general methods are useful for generating antenna array weights for data transmission. The reverse transmission sets the transmission weight in proportion to the conjugate reception weight, and the directivity mode sets the transmission weight in proportion to the conjugate packet steering vector. This reverse orientation mode is well suited for commercial and military air communication applications where interfering signals can be other members of a multipoint communication network.

Directional mode is useful for applications where hidden characteristics are a major consideration for operators and where jamming and eavesdropping platforms are mostly unlikely to be in the same location. This mode is useful for applications where there is a lot of interference in the communication platform, where maximum power must be delivered to the other side of the communication link in order to communicate where there is interference from radio transmission. However, this method does not have the attractive characteristics of directional energy away from other interferers in the affiliated communication system.

The directional mode also constitutes a multiplier adaptation strategy that, if the large spectral spreading factor is used by the airlink, can greatly simplify the complexity of the spreader.

The reverse transmission mode is described below. This reverse orientation mode sets the transmitter antenna array weight equal to the conjugate array weight calculated at signal reception. If the transmit and receive operators are used over the same frequency band, and some internal difference between the transmit and receive paths is equal, the transmitter antenna arrangement will have the same gain pattern as the antenna for the receiver. The transmitter antenna array can predict the direction of null in the direction of any interferers that were present at the time of signal reception. In each use the null depth is determined by the relative strength of the received interferer.

Where g _k is a K _array x one-dimensional vector and represents the multi-element spreading vector used in the transmission over the frequency cell “k”. The multi-element despreading vector used for reception across frequency cell "k" is represented by w _k , which is also a K _array x one-dimensional vector.

Embodiments of the present invention are preferably configured to spread the transmission packet using different settings of the K _array x 1 spreading (g _k ) weights across each spreading cell to provide a frequency selective transmission weight. This is frequency-selected by setting the (multi-element) spreading gain (g _k ) proportional to the K _array x 1 linear combiner spreading weight used for each frequency cell upon receiving a signal such as g _k = λw _k ^*. Sets the reverse transmission weight. This mode is particularly effective in an environment that is dominated by wideband interferers because the resulting null depth will be limited by the antenna array dispersion realized over each frequency cell. In this case, the processor will invalidate the source of interference not only in space but also in frequency. Only the transmitter antenna array invalidates each interferer in the frequency cell occupied by the interferer. This is fine for receiving signal-of-interrupt packets, but is ineffective for transmitting packets for the purpose of keeping packet radio signals away from the source of interference over the entire packet passband. This object cannot be achieved by any means if the number of partial-band interferers is equal to or exceeds the number of components in the antenna arrangement.

The directional transmission mode sets the transmitter antenna array weight equal to the (pair) K _array x 1 packet steering vector. If the transmit and receive operators are across the same frequency band, with the difference between the transmit and receive paths across the transmit and receive switches appropriately equalized, the resulting antenna array is the maximum radio energy of the adjacent link or communication link with the minimum transmit radio energy. To the other side. Directional arrangements typically ignore the location of the interferer, for example, assume that the interferer is anywhere in terms of communication link.

The directional method can be implemented on the basis of frequency-selection in the present invention. This exceptionally offers several advantages over a wideband communication link, for example a large value of K _spread or a very distributed communication channel where the packet steering vector varies significantly over the packet passband. However, this is not important because the maximum power mode does not fall very much by the minor error in the packet steering vector.

This prediction error can be large if the communication link is very congested or if the packet steering vector is predicted over a short communication interval, for example a single packet. In particular, the overall simple method is to direct the directional transmitter antenna array to a strong beam of transmit energy as an interference source in the surrounding environment. The directional transmission method or packet steering vector predictor is not so complicated as to reliably operate within the expected range of jamming and transmission scenarios, and requires simplicity to be affordable.

Three general steering vector prediction methods are preferred. First, the correlation method predicts a packet steering vector using the correlation between the received packet data and the predicted packet data. Second, the multicell ML type method predicts the packet steering vector using a maximum-capable (ML) predictor obtained under the presence of frequency-channelized (multicell) data and under appropriate simplification conditions. Third, the parametric method further refines the multicell predictor by suppressing the packet steering vector using an appropriate parametric model.

Correlation is the simplest of three methods for predicting packet steering vectors. A weakness of this method is that by considering the predictions obtained where there is a single interferer, the prediction changes to the packet steering vector plus the interference steering vector which is proportional to the cross-correlation between the received interference and the packet signal. will be. To reduce this cross-correlation to zero, the required time-bandwidth output (sample) would be greater than 1,000,000 samples if the 1 / S of the interfering signal, e.g. if the interfering source is 50 dB stronger than the packet signal. Required. As a result, this method is generally not appropriate.

The other two methods can overcome this limitation by using an optimized maximum possible (ML) prediction procedure to predict the packet steering vector. The resulting predictor may use a simple (nonparametric) or complex (parametric) steering vector model to provide an accurate steering vector predictor where there is a partial-band interferer or broadband. In addition, the performance of such a predictor can be predicted using a conventional Cramer-Rao bound analysis.

Useful performance bounds are derived from certain nonparametric steering vector predictions obtained in a multicell environment. This received data is divided into K _spread separate frequency cells, each proportional to an unknown complex steering vector and each containing a known (or predicted) packet baseband corrupted by additional complex Gaussian interference. The steering vector of the Pe cell is modeled by a _k = g _k , where "a" is a (frequency-independent) packet steering vector and g _k is a received single-antenna packet spreading gain scalar obtained from the k ^th spreading cell. Amount. Assuming complex Gaussian interference is independent for each cell, transient-white noise is on average 0, and an unknown autocorrelation matrix is at k ^th cells. to be.

Packet steering vector a is dimension to dimension assume any of the complex of the K _array vector for the K _array, for example, a will not be forced to be fixed for a given parameterized model set (e.g., azimuth and elevation angle Parameterized array manifold). Steering vector prediction was developed using this model, for example a nonparametric technique. H. VAN Trees, Detection, Estimation, and Modulation Theory, Part I, New York: Wiley, 1968. Using the Cramer-Rao bound to theory, a predetermined unbiased estimator of a is the prediction accuracy (mean-square error) bound by a given Cramer-Rao bound will have. Matrix R is the same interference autocorrelation matrix as the inverse of the average inverse autocorrelation matrix Refers to the generalized "average" of.

In a preferred embodiment, the spatial steering vector a and the spread spectrum gain g _k are calculated repeatedly using the following formula.

And

Where R _HkHk is the data autocorrelation matrix measured over the adaptive block in spectral cell _k , w _k is the spatial component of the spreading weight used in spectral cell k. The steering vector and spreading gain may be used to calculate an improved despreading weight (w _k ), which is a multiplex that performs spatial processing (linear combining in each frequency cell) by spectral processing (linear combining across frequency cells). It can be used for despreading procedures.

1 to 14, a stack carrier spread spectrum wireless communication device combined with a code nulling technique represents an alternative embodiment of the present invention. Code nulling interference cancellation techniques can be effectively combined with stack carrier spread spectrum techniques. For more details on code nulling design, see Brian Agee "Solving the Near-Far Problem: Exploitation of Spatial and Spectral Diversity in Wireless Personal Communication Networks," Wireless Personal Communication , edited by Theodore S. Rappaport, et al., Kluwer Academic Publishers, 1994, Ch. 7. and Sourour, et al., "Two Stage Co-channel Interference Cancellation in Orthogonal Multi-Carrier CDMA in a Frequency Selective Fading Channel," IEEE PIMRC '94, pp. 189-193. See. Also, Kondo, et al., "Multicarrier CDMA System with Co-channel Interference Cancellation," March 1994, IEEE, # 0-7803-1927, pp. 1640-1644. See.

The basic stack carrier spread spectrum wireless communication device shown in Figs. 1 to 14 includes space, frequency and / or code, e.g., space division multiple access (SDMA), frequency division multiple access (FDMA) and code division multiple access (CDMA). It is possible to combine in the multiple access embodiment of the present invention to separate the independent channels at the same time.

In the SDMA embodiment, the antenna arrangement may optionally be directed to a space for opening at least two regions, for example. Each transmitter and receiver pair in a region uses only the other side of its transmitter-receiver pair or tailors the corresponding antenna arrangement to exclude other pairs in other regions representing different multiple access channels. Embodiments of the present invention are distinguished by combining SDMA techniques with stack carrier spread spectrum techniques. For details on SDMA design, see Forssen, et al., "Adaptive Antenna Arrays for GSM900 / DSC1800," March 1994, IEEE # 0-7803-1927, pp. 605-609. And Talwar, et al., "Reception of Multiple Co-Channel Digital Signals using Antenna Arrays with Applications to PCS," 1994, IEEE # 0-7803-1825, pp. 790-794. See. See also Weis, et al., "A Novel Algorithm For Flexible Beam Forming for Adaptive Space Division Multiple Access Systems," IEEE PIMRC '94, pp. 729a-729e. See. The combination of CDMA with antenna arrays is described in Naguib, et al., In "Performance of CDMA Cellular Networks With Base-Station Antenna Arrays: The Downlink," 1994 IEEE, # 0-7803-1825, pp. 795-799. Is disclosed. Xu, et al., "Experimental Studies of Space-Division-Multiple-Access Schemes for Spectral Efficient Wireless Communications," 1994 IEEE, # 0-7803-1825, pp. 800-804. See. M. Tangemann, "Influence of the User Mobility on the Spatial Multiplex Gain of an Adaptive SDMA System," IEEE PIMRC '94, pp. 745-749. See.

In an FDMA embodiment, the subset of multiple carriers uses at least two subsets each having at least two frequency diversity carriers to establish each channel, eg, at least two channels. Each transmitter and receiver pair in the region fits the corresponding carrier subset to exclude other carrier subsets representing different multiple access channels. Embodiments of the present invention are distinguished by combining FDMA techniques with stack carrier spread spectrum techniques.

In the CDMA embodiment, several spreading and spreading weights use one set for each channel. Such multiple access is used in navigation receivers of the Global Positioning System (GPS). Embodiments of the present invention differ from the prior art by combining the CDMA technique shown in FIGS. 1-14 with a stack carrier spread spectrum technique. For a detailed description of CDMA design in a multi-carrier environment, see Fettweis, et al., "On Multi-Carrier Code Division Multiple Access (MC-CDMA) Modem Design," 1994 IEEE # 0-7803-1927, pp. 1670-1674. See. See also DaSilva, et al., "Multicarrier Orthogonal CDMA Signals for Quasi-Synchronous Communication Systems," IEEE Journal on Selected Areas in Communication, Vol. 12, No. 5, June 1994. See also Reiners, et al., "Multicarrier Transmission Technique in Cellular Mobile Communications Systems," March 1994, IEEE # 0-7803-1927, pp. 1645-1649. See. See also, Yee, et al., "Multi-Carrier CDMA in Indoor Wireless Radio Networks," IEEE Trans. Comm., Vol. E77-B, No. 7, July 1994, pp. 900-904. See. The use of CDMA in fading channels is described in Stefan Kaiser, "On the Performance of Different Detection Techniques for OFDM-CDMA in Fading Channels," Institute for Communication Technology, German Aerospace Research Establishment (DLR), Oberpfaffenhofen, Germany, 1994. . And Chandler, et al., "An ATM-CDMA Air Interface For Mobile Personal Communications," IEEE PIMRC '94, pp. 110-113. See. Further literature on this technique is described in Chouly, et al., In "Orthogonal multicarrier techniques applied to direct sequence spread spectrum CDMA systems," 1993 IEEE, # 0-7803-0917, pp. 1723-1728. to be.

The combination of multi-carrier CDMA and decorrelating interference cancellation is described in Bar-Ness, et al., In "Synchronous Multi-User Multi-Carrier CDMA Communication System With Decorrelating Interference Canceller," IEEE PIMRC '94, pp. 184-188. Described in

A multiple access method for stack carrier spread spectrum wireless communication consists of configuring the transmitter stack carrier spreading gain from the complex amplitude and phase gain of a complex sinusoid for each of a plurality of discrete frequency channels. Thereafter, any narrowband baseband data having a vector multiplier and a reverse frequency channel group is spread at the transmitter. The next step is spreading across a plurality of discrete frequency channels with a stack carrier spreading gain and then transmitting data from the transmitter simultaneously. When the receiver despreads a plurality of discrete frequency channels with vector inner linear combiners and frequency channel groups, any narrowband baseband pre-spread data is recovered with relative immunity to channel interference. Frequency channels may be distributed non-adjacent within multiple bands. Alternatively, the transmission may include a frequency-division multiplexing modulation scheme that overlaps and orthogonal frequency channels. Alternatively, the transmission of the data is in packets, where the baseband data has a multiplex frequency channel group structure based on orthogonal frequency-division and is spread, transmitted and despread in discrete packets.

Packets may be overlapping, contiguous or non contiguous in time. A preferred embodiment is to sequentially receive one or more packets from either side of the link and then sequentially send one or more packets. Sequential transmission and reception of multiple packets may enable asymmetric communication, for example by sending more packets in one direction than another, and may provide increased protection time between transmission and reception modes, for example For example, it can solve the base-to-base interference problem in the mobile communication network.

Combining discrete multi-tone orthogonal frequency-division multiplexing and antenna array processing techniques with discrete multi-tone-stack carrier and antenna array processing techniques has advantages in the dispersion-free nature of discrete multi-tone and discrete multi-tone stack carriers . In some applications requiring spatial interference cancellation, the performance of an adaptive antenna array is a necessity to mitigate the linear dispersion with little or no variation in front of the adaptive receiver (e.g., shear receiver defects, nonzero array windows). Significant improvement can be achieved by eliminating array apertures and fixed multipath scatters and reflectors. This is particularly useful in point-to-multipoint mobile communication networks that include a SDMA topology for communication between multiple users on the same set of frequency channels, because each spatial processor is within the cell. This is because you have to form (potentially) deep nulls in the direction of the interfering users.

Code Division Multiple Access (CDMA) transmits multiple signals over the same set of frequency channels using a set of linearly independent (usually orthogonal) spreading gains. These codes are split in the spreader using the appropriate combiner weights.

Direct-sequence spread spectrum systems may have advantages in space division multiple access multiple access, interference cancellation and channel equalization capabilities (code nulling techniques). Code nulling is either modulation-on-symbol direct-sequence spread spectrum (MOS-DSSS) or modulation-on-pulse direct-sequence spread spectrum (MOP) where the period of spread gain is equal to an integer number of message symbols (nominal one symbol interval). -DSSS) has been applied. Code nulling can be usefully combined with a stack carrier modulation scheme, for example, to cancel excess interferers like spectrum in an HF / VHF frequency hopping intercept system. In the prior art, common frequency hopping intercept techniques, including code nulling interference cancellation, have used stack carrier signals that mimic tropospheric scatter communication links. However, this technology extends to the point-to-point and point-to-multipoint communication in which the present carrier includes a stack carrier spread spectrum modulation scheme in the intended carriers, as well as the interferer. For example, a data-oriented blind adaptation method also includes optimizing the spreader based on known characteristics of the traffic and pilot data delivered by the communication system.

The present invention combines stack carrier spread spectrum communication and code nulling interference cancellation with a high capacity, high tolerance for channel distortion in a communication system, thereby relying less on the correlation between spread gains. Nearly orthogonal is not required, and embodiments of the present invention are less sensitive to narrowband interference or other system member stack carrier spread spectrum signals. This effect is optimized when code nulling interference cancellation is coupled to the stack carrier spread spectrum communication network. In particular, a stack carrier spread spectrum communication link that includes code nulling interference cancellation may support twice the equivalent modulation-on-symbol-direct-sequence spread spectrum system link given the same spreading gain and code nuller (linear combiner) complexity. Can be.

The present invention combines code nulling interference cancellation and data-directed methods used to adapt the spreader in a network. This combination provides a system with significant advantages in contention methods for point-to-point and point-to-multipoint communication. Such a system would benefit from the full time-bandwidth results of the communication system, thereby reducing the acquisition and tracking time of the spreader in the system. Such a system despreads and demodulates the intended stack carrier spread spectrum signal of the interest to the spreader, without having to know the spreading gain included in the signal transmitter (blind spreading characteristic), thereby selecting the code used in the network. The technique can be simplified or omitted, and it can be used to use reverse-oriented techniques that optimize the spreading gains based on communication channels and networks. Null Interference (inside or outside the cell) The stack carrier spread spectrum signal is received by the spreader without knowing the amount or spread gain of the interference signal, demodulating and reconstructing the interferer as well as the signal of the interest to the receiver. It greatly improves the complexity in sequential methods (typically non-linear) that must be modulated. Automatic compensation provides a fixed linear channel variance that includes the variance effect induced within the system front end, without having to know the channel variance or its actual prediction, thereby reducing the complexity of the system hardware as well as the spreading method.

Code nulling leads to spatial processing techniques and facilitates the use of reverse transmission methods to improve the performance and cost efficiency of the entire network.

Combining code nulling and spatial processing techniques with an adaptive antenna arrangement for beam-steering improves the range of conventional non-telecommunications transceivers. This combination may increase the performance of a multicell network by reducing interference present in adjacent cells. Null-steering for interference cancellation improves the performance of the communication network by allowing more dense packing. The denser packing is possible by separating frequency-coincident in-cell users in a spatial division multiple access topology. Antenna arrays can be used to increase code-null dimensions to combine time channels, e.g., MOS-DSSS systems as well as spatial channels, or code to combine frequency channels, e.g., stack carrier spread spectrum systems, as well as spatial channels. Increasing channel size can be combined directly with code nulling techniques.

In the stack carrier spread spectrum modulation scheme, the spreader allows the stack carrier to decrease the stack carrier spread spectrum spread gain by increasing the number of spatial channels so that the complexity of the code nuller remains constant as a function of the number of antenna components. This allows for a constant data-oriented receiver adaptation time. Linear complexity increases as the number of antennas and users in the communication link increases. And the spatial distribution of the user is reduced as the number of antenna beams increases.

The combination of code nulling data-oriented-adaptive reverse-directional transmission technology and stack carrier spread spectrum modulation provides an excellent communication mode. Point-to-point as well as point-to-multipoint communication links have user capacity, range, power and / or cost efficiency far exceeding the full channel preemphasis method.

Combining the stack carrier spread spectrum and adaptive antenna array processing is, for example, a coherent in a stack carrier spread spectrum mobile network where the interferer may be another member signal of the network and the multi-element antenna array is used primarily for the base stations of the network. It helps to remove runt interference spatially.

17 shows an example of a time-frequency format of a time division duplex communication system.

18 shows the actual tone format of the basic DMT modem.

19 shows a transmission / reception calibration method. In this figure there are two separate modes for system calibration and compensation. The SCSS cal signal applied to the receiver at the cal switch measures the reception path variance. An SCSS knife signal applied through a transmit modulator through a transmit switch to an output receiver measures the combined transmit and receive path variance. The transmission path is obtained from the combined received and transmitted knife data. Compensation is performed at the DSP back end by transmitting and processing the SCSS knife waveform.

20 is an integrated single-antenna (T / R) and DMT modem (DMT type SCMA) diagram.

21 is a diagram illustrating an example of a general single-link code-gated cross-SCORE spreading operation. This is preferably a mode for single-link processing. This makes it possible to use a cross-SCORE algorithm with the fastest convergence time (lowest TBP). It is not affected by timing and Doppler offset. The K _array interferer in each cell can be reliably removed. K _array SCSS signals can be separated. The drawback is that it cannot reliably separate> K _array SCSS signals (unencoded code nulling) and mistune for maximum-SINR solutions in highly frequency-shifted environments.

22 is an illustration of a single-link code-gated cross-SCORE despreading operation with a K _spread cell subset.

23 is an illustration of a single-link cross-SCORE algorithm with N _frame packets / adaptive frames. The spreader weight is calculated from the basic mode of the multi-set cross-SCORE eigenequation.

24 is an illustration of a single adaptive frame autocorrelation statistical calculation.

25 is an illustration of a cross-SCORE eigenequation with a K _spread cell subset. The spreader weight is calculated from the basic mode of the multi-set cross-SCORE eigenequation.

26 is an example of a _codekey generator with a K _part <K _spread cell subset.

27 is an illustration of an equivalent _codekey applicator with a K _part <K _spread cell subset.

28 is an illustration of a cross-SCORE eigenequation with a K _part cell subset. The spreader weight is calculated from the basic mode of the multi-set cross-SCORE eigenequation.

29 is an illustration of a cross-SCORE eigenequation with two cell subsets. The spreader weight is calculated from the basic mode of the multi-set cross-SCORE eigenequation.

30 is an illustration of a multi-link code-gated cross-SCORE spreader. This is an improved mode for multi-link processing. This allows the SCSS interference condition to tailor the cross-SCORE convergence time. This is not affected by timing and Doppler offset. This can reliably eliminate the K _array interferer in each cell. This may remove the K and K _{array score} SCSS signal. Its drawback is> K and K _{array score} SCSS signal can not be separated so (incomplete code nulling) the reliability, high frequencies - is that O adjusted for maximum -STAR solutions in environmental variation.

31 is an illustration of a single-link code-gated auto-SCORE spreading operation with gating over frequency and two cell subsets. Modes for highly mobile systems are preferred. This can separate the K _array K _score SCSS link. This can eliminate K _array non-SCSS interferers in each cell. This is not affected by timing and Doppler offset. The drawback of this is that the> K _score SCSS link cannot be separated and requires (simple) timing tracking as part of the spreading algorithm.

32 is an illustration of a single-link code-gated auto-SCORE despreading operation with gating over frequency and two cell subsets.

33 is an illustration of an auto-SCORE eigenequation with gating over frequency and two cell subsets.

34 is an illustration of single-link code-gated auto-SCORE spreading with gating over time and a half speed of excess gate. This is a preferred mode for low mobility systems. This can separate the K _array and K _spread SCSS links. This can eliminate K _array non-SCSS interferers in each cell. This is not affected by timing and Doppler offset. 3 dB SNR gain is provided to the spreader. The drawback of this is that the capacity is halved and requires (simple) Doppler tracking as part of the despreading algorithm.

35 is an illustration of single-link code-gated auto-SCORE despreading with gating over time and a half speed of excess gate.

In summary, adaptive antenna arrangements can be used to increase network system capabilities by beam-steering, null-steering or combined beam-and-null steering. This null steering or combined beam and null steering technique is combined with a DMT / OFDM frequency channel outside the channel group used in the present invention as an SCSS spreader / despreader.

Although the present invention has been described in terms of preferred embodiments only, it is to be understood that the invention is not limited to those described herein. It will be apparent to one skilled in the art that, after reading the above disclosure, there will be various variations and modifications. Accordingly, modifications and variations that do not depart from the spirit and scope of the present invention are construed as falling within the claims of the present invention.

Claims (86)

One or more wireless transmitters for transmitting a plurality of radio frequency (RF) carriers; One or more wireless receivers for receiving one or more subsets of at least two of the plurality of radio frequency carriers; At least one spreader coupled to each transmitter to independently and independently modulate the amplitude and phase of at least two (RF) carriers having a first digital spread gain and first data; One or more despreaders coupled to each receiver for independently demodulating the amplitude and phase of two or more of the (RF) carriers having the first digital spreading gain to recover the first data; And Multiple access means connected to a transmitter, receiver, spreader, and spreader to provide separate communication channels in one or more of a space division multiple access (SDMA), a frequency division multiple access (FDMA), and a code division multiple access (CDMA) method. Multi-access communication system, characterized in that made. The method of claim 1, The SDMA further includes an antenna array connected to the transmitter and the receiver, and provides selective data channel transmission and reception between the pair of transmitter and receiver according to the relative spatial position. The method of claim 1, The FDMA further includes a minimum number of radio frequency carriers for providing at least two subsets of carriers for communication over additional data channels between transmitter and receiver pairs in accordance with a matching subset of radio frequency carriers. Multiple access communication system characterized by. The method of claim 1, The CDMA includes at least a second digital spread gain and second data, and provides communication of at least the first and second data between a pair of transmitters and receivers in accordance with a matching subset of the digital spread gains. Multiple access communication system. A wireless transmitter system providing spatial and frequency dispersion, An antenna system comprising a group of spatially distributed positive integer "n" individual antennas and providing an equal number of positive integer "n" spatially distributed communication channels; And a separate amplifier connected to the corresponding antenna of the antenna system, each amplifier having an adjustable gain providing controlled steering of the null and beam of radio frequency signal transmission for the radially distributed spatial communication channel. Banks; A discrete multi-tone stack carrier spread spectrum transmission modulator coupled to the amplifier bank to provide a plurality of frequency distributed communication channels; A spreader having respective outputs and data inputs coupled to said modulator, said spreader providing spreading of data across all of said plurality of frequency-distributed communication channels simultaneously; And And steering means connected to said bank of radio frequency amplifiers for selecting one of said positive integer "n" radially distributed spatial communication channels. The method of claim 5, The system further provides polarization dispersion in which the individual antennas are polarized. A wireless receiver system providing spatial and frequency dispersion, An antenna system comprising a group of spatially distributed positive integer "n" individual antennas and providing an equal number of positive integer "n" radially distributed spatial communication channels; And a separate amplifier connected to the corresponding antenna of the antenna system, each amplifier having an adjustable gain providing controlled steering of the null and beam of radio frequency signal transmission for the radially distributed spatial communication channel. Banks; A discrete multi-tone stack carrier spread spectrum demodulator coupled to the amplifier bank for providing a plurality of frequency distributed communication channels; A dispenser having respective inputs and data outputs coupled to the demodulator and providing a spreading of data contained across all of the plurality of frequency-distributed communication channels; And And steering means connected to said bank of radio frequency amplifiers to select one of said positive integer "n" radially distributed spatial communication channels. The method of claim 6, And computing means for determining a radially distributed spatial communication channel address of the target receiver. A multiple access method for stack carrier spread spectrum wireless communication, Configuring a stack carrier spreading gain at the transmitter from the complex amplitude and phase gain of the complex sinusoid for each of the plurality of discrete frequency communication channels; Spreading at the transmitter any narrowband baseband pre-spread data having a vector multiplier and a reverse frequency communication channel; Simultaneously spreading the data from the transmitter after spreading over the plurality of discrete frequency communication channels having the stack carrier spreading gain; And Said any narrowband baseband pre-spread data is recovered with relative immunity to communication channel interference, and despreading said plurality of discrete frequency communication channels at a receiver having a vector inner linear synthesizer and a frequency communication channel group; Multiple access method comprising a. The method of claim 9, The configuring step is characterized in that the frequency communication channel is distributed in multiple bands without adjacent. The method of claim 10, And said simultaneously transmitting includes a frequency division multiplexing scheme that overlaps and orthogonalizes said frequency communication channels. The method of claim 11, The transmitting simultaneously packetizes the data, wherein the baseband data is spread, transmitted and despread in discrete packets that are overlapping, contiguous or non-contiguous in time in an orthogonal frequency division multiplexed frequency communication channel structure. Multiple access method characterized in that. An interference cancellation method for a stack carrier spread spectrum wireless communication, Configuring a stack carrier spreading gain at the transmitter from the complex amplitude and phase gain of the complex sinusoid for each of the plurality of discrete frequency communication channels; Spreading at the transmitter any narrowband baseband pre-spread data having a vector multiplier and a reverse frequency communication channel; Simultaneously spreading the data from the transmitter after spreading over the plurality of discrete frequency communication channels having the stack carrier spreading gain; Said any narrowband baseband pre-spread data is recovered with relative immunity to communication channel interference, and despreading said plurality of discrete frequency communication channels at a receiver having a vector inner linear synthesizer and a frequency communication channel group; ; And And code nulling with interference canceling means in accordance with the information obtained from said despreading step. An adaptive antenna arrangement method for stack carrier spread spectrum wireless communication, Configuring a stack carrier spreading gain at the transmitter from the complex amplitude and phase gain of the complex sinusoid for each of the plurality of discrete frequency communication channels; Spreading at the transmitter any narrowband baseband pre-spread data having a vector multiplier and a reverse frequency communication channel; Simultaneously spreading the data from the transmitter after spreading over the plurality of discrete frequency communication channels having the stack carrier spreading gain; Said any narrowband baseband pre-spread data is recovered with relative immunity to communication channel interference, and despreading said plurality of discrete frequency communication channels at a receiver having a vector inner linear synthesizer and a frequency communication channel group; ; And And adjusting gains of several amplifiers connected to said transmitter and antenna array by said spread baseband data. A time division duplex method for stack carrier spread spectrum wireless communication, Transmitting the plurality of first discrete frequency communication channels to a distal transmitter and dividing the time into timeslots arranged to receive the plurality of second discrete frequency communication channels from the distal transmitter; Configuring a stack carrier spreading gain in a proximal transmitter from a complex amplitude and a phase gain of a complex sinusoid for at least one of a plurality of said first or second discrete frequency communication channels; Spreading at the proximal transmitter any narrowband baseband pre-spread data having a vector multiplier and a reverse frequency communication channel; Simultaneously spreading the data from the proximal transmitter after spreading over the plurality of first discrete frequency communication channels having the stack carrier spreading gain; The arbitrary narrowband baseband pre-spread data is recovered with immunity relative to the communication channel interface and disposes the plurality of second discrete frequency communication channels at a proximal receiver having a vector inner linear synthesizer and a frequency communication channel. Reading; And And controlling the time division step with precise time information obtained from a timing signal source available for both the distal and proximal transmitters and the distal and proximal receivers. The method of claim 15, And said controlling step comprises receiving system time information from a navigation satellite orbiting in orbit. A wireless transmitter system, A multi-tone transmitter arrangement for transmitting a multi-spectrum carrier signal in accordance with a spectral weighting operation by a computer identifying a plurality of first individual remote receivers; And A spatial arrangement of transmit power of the multi-spectrum carrier signal transmission in accordance with a spatial weighting operation by a computer identifying a plurality of second individual remote receivers, said antenna arrangement comprising an antenna arrangement coupled to said transmitter arrangement; Wireless transmitter system. A wireless receiver system, A multi-tone receiver arrangement for receiving a multi-spectrum carrier signal in accordance with a spectral weighting operation by a computer identifying a plurality of first individual remote transmitters; And Providing a spatial adjustment of the received power to the multi-spectrum carrier signal acceptance in accordance with a spatial weighting operation by a computer identifying a plurality of second individual remote transmitters, the antenna arrangement being coupled to the receiver arrangement. Characterized by a wireless receiver system. As a wireless communication system, A multi-tone transmitter arrangement for transmitting a multi-spectrum carrier signal in accordance with a spectral weighting operation by a computer identifying a plurality of first individual remote receivers; A first antenna arrangement coupled to the transmitter arrangement for providing spatial adjustment of transmit power of the multi-spectrum carrier signal transmission in accordance with a spatial weighting operation by a computer identifying a plurality of second individual remote receivers; A multi-tone receiver arrangement for receiving a multi-spectrum carrier signal in accordance with a spectral weighting operation by a computer identifying a plurality of first individual remote transmitters; And Providing a spatial adjustment of the received power of said multi-spectrum carrier signal acceptance in accordance with a spatial weighting operation by a computer identifying a plurality of second individual remote transmitters, said second antenna array being connected to said receiver arrangement. A wireless communication system characterized by the above. The method of claim 19, And providing a single batch operation of both the spectral weight and the spatial weight, the computer further coupled to a transmitter arrangement and a first antenna arrangement. The method of claim 19, And providing a single batch operation of both the spectral weight and the spatial weight, the computer further coupled to a receiver array and a second antenna array. The method of claim 19, Provide a single batch operation of both spectral weights and spatial weights in use by the receiver arrangement and the second antenna arrangement, repeat for both spectral weights and spatial weights in use by the transmitter arrangement and the first antenna arrangement, and A computer coupled to the array, the receiver array, the first antenna array, and the second antenna array; And wherein the unique spatial and spectral characteristics of the plurality of first and second individual remote transmitters are used to optimize return transmission to the plurality of first and second individual remote receivers. Digital communication transmitted over a wireless medium and spread and modulated on each of the plurality of stack carrier signals using separate spreading gains for each of the plurality of stack carrier signals received at the receiver as a plurality of received stack carrier signals. As a method of recovering a signal, The received stack carrier signals and a channel bandwidth that can be separated from the channel band different from the plurality of received stack carrier signals to identify a baseband signal for each of the received stack carrier signals. Channelizing each of the stack carrier signals; By applying a spread weight different from the spreading gain for each of the received baseband signals, and combining the received baseband signals to obtain a baseband signal that compensates for interference to maximize signal-to-noise ratio and signal-to-interference ratio Despreading; And Removing at least one of time distortion and frequency distortion present in the baseband signal to obtain a recovered digital communication signal corresponding to the digital communication signal. The method of claim 23, wherein And wherein said despreading blindly despreads the plurality of received stack carrier signals. The method of claim 24, And said blind despreading uses the basic mode of a generalized eigen equation. The method of claim 25, And said blind spreading uses the basic modes of a generalized eigen equation. The method of claim 26, The eigenequation is a code gated self coherence restoral eigenequation. The method of claim 25, And the maximum code gated self-recovery eigenvalue of the generalized eigenvalue decreases by an expected mean during the blind despreading step and is proportional to an expected standard deviation. The method of claim 23, wherein Wherein said channelizing, despreading, and removing steps are each performed repeatedly on a plurality of sequentially received stack carrier signals to obtain related digital communication signals that are recovered sequentially. The method of claim 29, And wherein the plurality of sequentially received stack carrier signals is asynchronous. The method of claim 29, And wherein the plurality of sequentially received stack carrier signals are each received during an associated time division duplex interval and use a network clock to determine the time division duplex interval. The method of claim 29, And the reception time duplex section is asymmetrical with respect to the transmission time duplex section. The method of claim 31, wherein And the reception time duplex section is symmetrical with respect to the transmission time duplex section. The method of claim 31, wherein And wherein the plurality of sequentially received stack carrier signals are received as a plurality of packets during a single time division duplex period. The method of claim 31, wherein And wherein the plurality of sequentially received stack carrier signals are received as a single packet during a single time division duplex period. The method of claim 31, wherein And wherein said network clock is obtained from universal time. The method of claim 31, wherein And said network clock is obtained from data in said digital communication signal. The method of claim 23, wherein A second spreading gain for the second data communication signal transmitted from the receiver as a plurality of second stack carrier signals is suitably determined based on the spread weight to be directed to a frequency at which the minimum radiation interferes Way. The method of claim 38, And the second spreading gain is set in proportion to the conjugate spread weight such that a gain pattern of the plurality of second stack carrier signals is substantially equal to a gain pattern of the plurality of stack carrier signals. The method of claim 23, wherein A plurality of recovered digital communication signals are simultaneously recovered from a plurality of received stack carrier signals, and the plurality of digital communication signals having an associated separate code key are despread to identify the plurality of received stack carrier signals. Method used for each of the steps. The method of claim 40, Wherein each of said separate code keys only modulates some of said plurality of received stack carrier signals. 42. The method of claim 41 wherein Wherein each of said separate code keys modulates one of the even and odd stack carrier signals received from said plurality of received stack carrier signals. The method of claim 23, wherein And said digital communication signal is a plurality of symbols, each said symbol being modulated on a plurality of said stack carrier signals with different discrete tones. The method of claim 23, wherein Wherein said digital communication signal is a plurality of bits, each said bit being modulated onto a plurality of said stack carrier signals with different discrete tones. The method of claim 23, wherein Wherein said time distortion is due to a Doppler frequency offset. The method of claim 23, wherein Wherein said frequency distortion is caused by time variance. The method of claim 23, wherein And wherein said frequency distortion is a propagation delay. The method of claim 23, wherein And said removing step removes both time distortion and frequency distortion. 49. The method of claim 48 wherein Wherein said time distortion is due to a Doppler frequency offset. 49. The method of claim 48 wherein Wherein said frequency distortion is caused by time variance. 49. The method of claim 48 wherein The frequency distortion is a propagation delay. 49. The method of claim 48 wherein The frequency distortion is a propagation delay. The method of claim 23, wherein The received stack carrier signal comprises a guard time period for compensating for an unknown propagation delay, and the method is not synchronized with the received stack carrier signal until the despreading step is finished. . The method of claim 23, wherein The received stack carrier signal comprises a guard frequency band to compensate for an unknown Doppler frequency offset, and the method is not synchronized with the received stack carrier signal until the despreading step is finished. Way. A method for recovering a spread digital communication signal using a spreading gain when transmitted and received at a receiver as a received signal, the method comprising: Despreading the received signal to obtain a despread signal; And Removing a Doppler time delay from said spread signal to obtain a recovered digital communication signal corresponding to said transmitted digital communication signal. A method of recovering a plurality of transmitted symbols received at a receiver as a plurality of discrete multi-tones spread using a separate spreading gain and having substantial frequency diversity, Despreading each of said plurality of discrete multiple tones and a plurality of said spread multiple tones corresponding to one of said plurality of symbols to obtain a plurality of spread multiple tones; And Removing a Doppler time delay from the spread multiple tones to obtain a plurality of recovered symbols corresponding to the plurality of transmitted symbols. The method of claim 56, wherein The transmitted symbols are spread and modulated on each of the plurality of stack carrier signals using separate spreading gains for each of the plurality of stack carrier signals, each of the plurality of stack carrier signals being different from the plurality of stack carrier signals. And a channel bandwidth that can be separated from the channel bandwidth. The method of claim 57, And wherein said despreading blindly despreads the plurality of received stack carrier signals. The method of claim 58, And said blind spreading uses a basic mode of a generalized eigen equation. The method of claim 58, And said blind spreading uses the basic modes of a generalized eigen equation. The method of claim 60, The eigenequation is code gated self-coherence recovery eigenequation. The method of claim 59, And the maximum code gated self-recovery eigenvalue of the generalized eigenvalue decreases by an expected mean and is proportional to an expected standard deviation during the blind despreading step. A method of spreading a digital communication signal, In order to obtain a plurality of digital communication signals spread like a spectrum, the digital communication signals are spread like a spectrum on each of the plurality of stack carrier signals having a channel bandwidth that can be separated from the channel bandwidth different from the plurality of stack carrier signals. Reading; Spatially spreading each of the plurality of digital communication signals spread like a spectrum to obtain a plurality of digital communication signals spread spatially and like a spectrum; And Transmitting from each antenna component of the multi-element antenna array to a receiver the associated signals of the plurality of digital communication signals that are spread spatially and spectrally over a wireless medium. As a method of digital communication, At a movable transmitter, spreading spread digital information using a separate spreading gain on each of the plurality of stack carrier signals having a channel bandwidth that can be separated from the channel bandwidth different from the plurality of stack carrier signals; Transmitting each of the stack carrier signals from the movable transmitter to a receiver over a wireless medium; Receiving at the receiver the plurality of transmitted stack carrier signals as received stack carrier signals; Channelizing each of the received stack carrier signals to identify a baseband signal for each of the received stack carrier signals; By applying a spread weight different from the spreading gain for each of the received baseband signals and combining the received baseband signals to obtain a baseband signal that compensates for interference to maximize signal-to-noise and signal-to-interference ratios. Despreading; And Processing the baseband signal to obtain recovered digital information corresponding to the transmitted digital information. The method of claim 64, wherein And said processing removes a Doppler time delay from said baseband signal. The method of claim 64, wherein Each of the plurality of movable transmitters, which spread the digital information using a random, non-orthogonal spreading gain to spread the digital information on a plurality of the respective stack carrier signals, spreads and transmits the digital information. Performing each of the steps; In the step of receiving the transmitted plurality of stack carrier signals, receiving the transmitted stack carrier signals from each transmitter at a receiver; In the channelizing step, conveying each received stack carrier signal; In the despreading step, for each of the plurality of transmitters, each of the plurality of received stacks independently delivered to obtain one baseband signal corresponding to the digital information transmitted by one of the plurality of transmitters Combine carrier signals; And in said processing, processing said baseband angle signal to obtain said recovered digital communication signal in response to said transmitted digital communication signal for each of said movable transmitters. The method of claim 66, wherein And wherein said processing removes the Doppler time delay present in each baseband signal. The method of claim 67 wherein And wherein the plurality of movable transmitters are geographically separated, each having a separate transmission path for the receiver. The method of claim 67 wherein A multi-element antenna arrangement is used in the receiver, different of the elements are used to differentiate areas, and spatial division multiple access is used to differentiate different ones of the transmitters. 66. The method of claim 65, Frequency division multiple access is used to differentiate between different transmitters. The method of claim 67 wherein Code division multiple access is used to differentiate between different transmitters. The method of claim 71 wherein And modulating a separate code key on some of the plurality of stack carrier signals associated with each transmitter. As a method of digital communication, A first base station having a multi-element antenna arrangement transmits a different signal among the plurality of each stack carrier signal and the stack carrier signal each having a channel bandwidth that can be separated from the channel bandwidth different from the plurality of stack carrier signals. Spreading digital information using a separate spreading gain for each of the antenna components used; Transmitting each of the stack carrier signals from the first base station to a second base station via a wireless medium; At the second base station using a second multi-element antenna array that is each component of the second antenna used to receive a different one of the received stack carrier signals, the transmitted plurality of carriers as a received stack carrier signal Receiving a signal; Channelizing each received stack carrier signal to identify a baseband signal for each of the received stack carrier signals; By applying a spread weight different from the spreading gain for each of the received baseband signals, and combining the received baseband signals to obtain a baseband signal that compensates for interference to maximize signal-to-noise ratio and signal-to-interference ratio And despreading. The method of claim 73, wherein The second spreading gain for the second data communication signal transmitted from the multi-element antenna array of the second base station as a plurality of second stack carrier signals is suitably determined based on the spread weight so that the minimum radiation is And directed towards the interfering frequency. The method of claim 74, wherein And the second spreading gain is set in proportion to the conjugate spread weight such that a gain pattern of the plurality of second stack carrier signals is substantially equal to a gain pattern of the plurality of stack carrier signals. The method of claim 73, wherein And the second spreading gain for the second data communication signal transmitted from the multi-element antenna arrangement of the second base station is suitably determined such that the maximum radiation is directed to the desired base station. 77. The method of claim 76, And said second spreading gain is suitably determined using spatially and spectrally coupled steering vectors. The method of claim 73, wherein And wherein said separate spreading gains associated with each of said plurality of stack carrier signals are linearly independent and not orthogonal. As a method of digital communication, In a first base station, digital information is obtained by using a separate spreading gain for each stack carrier signal on each of the plurality of stack carrier signals having a channel bandwidth that can be separated from the channel bandwidth different from the plurality of stack carrier signals. Spreading; Transmitting each of the stack carrier signals from the first base station to a second base station via a wireless medium; At the second base station using a multi-element antenna arrangement, receiving the transmitted plurality of carrier signals as a received stack carrier signal; Channelizing each received stack carrier signal to each component of the array to identify a baseband signal for each of the received stack carrier signals; Using linear combiner dimensionality, consisting of spectral and spatial dimensions, apply the spreading gain and the different spread weight for each of the received baseband signals, and compensate for the interference to compensate for the signal to noise ratio and signal Despreading by combining the received baseband signals to obtain a baseband signal that maximizes an interference ratio. 80. The method of claim 79 wherein The second spreading gain for the second data communication signal transmitted from the multi-element antenna array of the second base station as a plurality of second stack carrier signals is suitably determined based on the spread weight so that the minimum radiation is Directing to an interfering frequency. 81. The method of claim 80, And the second spreading gain is set in proportion to the conjugate spread weight such that the gain patterns of the plurality of second stack carrier signals are substantially the same as the gain patterns of the plurality of stack carrier signals. 80. The method of claim 79 wherein And the second spreading gain for the second data communication signal transmitted from the multi-element antenna arrangement of the second base station is suitably determined so that the maximum radiation is directed to the desired base station. 83. The method of claim 82, And said second spreading gain is suitably determined using spatially and spectrally coupled steering vectors. 80. The method of claim 79 wherein Wherein said spatial dimension and spectral dimension are variable with respect to a plurality of other than said first base station. 80. The method of claim 79 wherein And wherein said separate spreading gains associated with each of said plurality of stack carrier signals are linearly independent and not orthogonal. A method of despreading a digital communication signal received at a receiver via a wireless medium, At each antenna component of a multi-element antenna array, receiving a plurality of each stack carrier signal having a channel bandwidth that can be separated from the channel bandwidth different from the plurality of stack carrier signals; Spatially despreading the plurality of stack carrier signals to obtain a spatially despread digital communication signal; And And despreading each of said plurality of spatially despreaded digital communication signals like a spectrum to obtain a spatially and spectrumly despread digital communication signal.