JP2019146115A - System and method for radio transmission - Google Patents

Abstract

To guarantee communication quality and enable communication of a shared method having high reliability, even in the case of an increased number of simultaneous connections transmitted from a plurality of terminals and the occurrence of collision between both signals having low delays.SOLUTION: A radio terminal generates a transmission signal and a continuous transmission signal from transmission target data to continuously transmit to the base station the above signals as transmission data. The base station performs equalization and demodulation of the continuously transmitted transmission data according to the characteristics of the received power, and after synthesizes the demodulated transmission signal with the continuous transmission signal, outputs the reception data of the transmission target. The base station then generates a reproduced transmission signal from the output reception target data, and reproduces a reproduced continuous transmission signal from the reproduced transmission signal, and performs the convolution of a re-modulated signal to generate the same data signal equivalent to the reception signal, and then repeats subtracting the reception data to separate the reception data.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a wireless transmission system and a wireless transmission method for receiving transmission data from a plurality of wireless terminals at a common base station.

  In future 5th generation mobile radio transmission systems (hereinafter referred to as 5G), high capacity, low delay, multiple connections, etc. are required for the system, and various research and development are being promoted in various countries around the world to achieve this. . 5G is expected not only to increase the capacity of the fourth generation mobile radio transmission system (hereinafter referred to as 4G) but also to efficiently handle Internet of Things (hereinafter referred to as IoT) communication. ing. Therefore, an enormous number of IoT terminals and wireless terminals (UE: User Equipment) are connected to a base station (BS: Base Station or eNB: evolved Node B), and various services have been provided.

  In addition, in IoT communication, there is also a service that requires each communication and control exchange with low delay, such as automatic driving of a car or the like. In such a case, a huge number of terminals are included. Is required in a base station while low delay communication is required. For this reason, in the recent IoT era, there is a need for a new radio access technology capable of accommodating small-sized data transmitted from a large number of sensor devices in a base station with high frequency efficiency. Low-delay communication is required for IoT devices that require real-time performance such as automatic driving vehicles and the like.

  However, the access method used in the current mobile communication network (LTE-A: Long Term Evolution-Advanced) is that the terminal station makes a request for allocation of communication resources to the base station, and then the terminal requested by the base station Since this is a method for allocating communication resources, it is not suitable for communication requiring low delay. The low delay uses an access method called 4-step RACH (RACH: Random Access Channel) in the current random access, and therefore it takes at least 10 ms from the connection request to the start of communication from the resource allocation.

  When this method is applied to IoT communication with a small amount of data to be transmitted, a single terminal occupies a communication slot in addition to a large overhead. Since there is only one terminal that can access one resource, there is a concern about tightness of RB (RB: Resource Block) and a significant decrease in frequency utilization efficiency.

  Therefore, research and development of a contention-based communication method in which a plurality of terminal stations share a communication slot is underway, and high reliability of the communication is an important issue. In the current mobile communication network, the base station manages the communication resources used by the terminal stations, and controls so that transmissions of multiple terminal stations do not collide in the same communication resources. It is considered that contention-based communication that allows collisions at a station is put into practical use, but at this time, the technology for improving communication reliability is still unbalanced.

  In communication using the conventional technology as described above, it is considered that a method of sharing communication resources will be put into practical use in the next generation mobile communication network, but the issue of the sharing method (contention-based communication) is how to improve communication quality. However, since the signals of the terminal stations interfere with each other at the base station, a technique for suppressing and removing this interference is necessary.

  Already, non-orthogonal multiple access (NOMA: Non-Orthogonal Multiple Access, hereinafter referred to as NOMA) as a technology for realizing multiple connections, grant-free communication (GF: Grant Free, hereinafter referred to as GF) as a technology for realizing low-delay communication. In addition, for interference / suppression technology, successive interference suppression / removal method (SIC: Successive Interference Cancellation, hereinafter referred to as SIC) or parallel interference suppression / removal method (PIC: Parallel Interference Cancellation, hereinafter referred to as PIC). However, it is very difficult to make the communication quality equivalent to the non-shared system method even if these technologies are used. Technology to ensure the communication quality without increasing the communication delay time in order to realize the communication of a shared system with the reliability are required.

Hasan, Monowar, Ekram Hossain, and Dusit Niyato. "Random access for machine-to-machine communication in LTE-advanced network; issue and approaches." IEEE Communications Magazine 51.6, P86-93, 2013

  Even if a collision occurs in signals transmitted from a plurality of terminals, low delay and communication quality are ensured, and high-reliability shared communication can be performed even when the number of simultaneous connections increases.

  In order to solve the above-described problems, the present inventors have invented a wireless transmission system and a wireless transmission method for receiving transmission data from a plurality of wireless terminals at a common base station. The plurality of wireless terminals continuously transmit the generated transmission signal and the continuous transmission signal as transmission data, respectively, a transmission signal from the transmission target data, a means for generating a continuous transmission signal based on the transmission signal, Means for transmitting to the base station. The base station receives transmission data continuously transmitted from a plurality of wireless terminals as reception data, and equalizes and demodulates the reception data according to the order of the signal characteristics of the reception power of the reception data, and demodulates the reception data Means for outputting the transmission target data after combining the transmission signal and the continuous transmission signal, a transmission signal as a reproduction transmission signal using the output transmission target data, and a reproduction continuous transmission signal based on the reproduction transmission signal A means for generating a continuous transmission signal, and a reception transmission data and a reception data that is the same as the data reproduced from the reproduction continuous transmission signal are subtracted from the received data, and other reception data is subject to transmission according to the order of signal characteristics. Means for performing a series of processes for outputting data.

  The radio transmission system according to claim 1 is a radio transmission system that receives transmission data from a plurality of radio terminals at a common base station, and the plurality of radio terminals transmit a transmission signal from data to be transmitted; Means for generating each of the continuous transmission signals based on the transmission signal, and means for continuously transmitting the generated transmission signal and the continuous transmission signal as transmission data and transmitting to the base station, The base station receives transmission data continuously transmitted from the plurality of wireless terminals as reception data, and equalizes and demodulates the reception data according to the order of signal characteristics of reception power of the reception data And means for outputting the transmission target data after combining the demodulated transmission signal and the continuous transmission signal, a transmission signal as a reproduction transmission signal using the output transmission target data, and the re-transmission signal. Means for generating a continuous transmission signal as a reproduction continuous signal based on the transmission signal, and subtracting the reception data that is the same as the reproduction transmission signal and the data reproduced from the reproduction continuous transmission signal from the received data; And means for performing a series of processes for outputting the data to be transmitted on other received data in accordance with the order of characteristics.

  According to a second aspect of the present invention, in the radio transmission system according to the first aspect, the signal characteristic of the received data is the output power of the received power.

  According to a third aspect of the present invention, in the radio transmission system according to the first or second aspect, the signal characteristics are such that the power of the intersymbol interference and the power of the interference signal are different in bit or symbol units. It is characterized by being.

  According to a fourth aspect of the present invention, in the radio transmission system according to the first to third aspects of the present invention, each of the signals includes a terminal identification area, a channel estimation area, and a payload carrying area. Features.

  According to a fifth aspect of the present invention, in the radio transmission system according to the first to fourth aspects, the base station further includes a plurality of antennas, and transmits transmission data continuously transmitted from a plurality of terminal stations. It receives, weights based on the power ratio of the channel frequency response of each said antenna, and synthesize | combines each said signal, It is characterized by the above-mentioned.

  The radio transmission method according to claim 6 is a radio transmission method in which transmission data from a plurality of radio terminals is received by a common base station, wherein the plurality of radio terminals transmit a transmission signal from data to be transmitted; A first step of generating a continuous transmission signal based on the transmission signal, a second step of continuously transmitting the generated transmission signal and the continuous transmission signal as transmission data, and transmitting to the base station; And the base station receives, as reception data, transmission data continuously transmitted by the plurality of wireless terminals, and the reception according to the order of the signal characteristics of the reception power of the reception data. A fourth step of equalizing and demodulating data, combining the demodulated transmission signal and continuous transmission signal and outputting the transmission target data, and transmitting the transmission target data as a transmission transmission signal signal A fifth step of generating a continuous transmission signal as a reproduction continuous transmission signal based on the reproduction transmission signal, and reception that is the same as the data reproduced from the reproduction transmission signal and the reproduction continuous transmission signal from the received data A sixth step of subtracting data and performing a series of processes related to output of the data to be transmitted on other received data according to the order of the signal characteristics.

  According to the first invention, the wireless terminal generates a transmission signal and a continuous transmission signal from data to be transmitted, continuously transmits the signal as transmission data, and the base station side is based on the signal characteristics of the received transmission data. The received data is equalized and demodulated, the transmission signal and the continuous transmission signal are combined, the data to be transmitted is output, and the transmission signal is output as the reproduced transmission signal using the output transmission target data, and this reproduced transmission signal Based on the above, a continuous signal is generated as a playback continuous signal, and the same data as the playback transmission signal and the data reproduced from the playback continuous signal is subtracted from the received data. Means for performing a series of processing related to the output of the data to be transmitted. For this reason, it is possible to perform communication processing that achieves both a large number of connections and a low delay. As a result, even if a collision occurs in signals transmitted from a plurality of terminals, low delay and communication quality are ensured, and even if the number of simultaneous connections increases, highly reliable shared communication is possible.

  According to the second to third inventions, it is possible to detect the strength of the power of transmission data transmitted from the wireless terminal side, and the difference between the power of intersymbol interference and the power of the interference signal. Thereby, a large number of terminals can be discriminated simultaneously. This makes it possible to obtain stable output characteristics even when the temperature changes. For this reason, even if the number of simultaneous connections increases, a highly reliable shared communication can be established.

  According to the fourth aspect of the invention, transmission data transmitted from the radio terminal is composed of a terminal identification area, a channel estimation area, and a payload carrying area. This eliminates the need for communication between the wireless terminal and the base station, which is required to obtain a grant from the base station by the conventional GF. For this reason, even when a collision occurs in signals transmitted from a plurality of terminals, it is possible to reduce the delay.

  According to the fifth invention, the base station further includes a plurality of antennas, receives transmission data continuously transmitted from the plurality of terminal stations, and performs weighting based on the power ratio of the channel frequency response of each antenna. Do. Thereby, even if a collision occurs in signals transmitted from a plurality of terminals, transmission data from each wireless terminal can be received more accurately and efficiently. For this reason, low delay and communication quality are ensured, and highly reliable shared communication can be established even if the number of simultaneous connections increases.

It is a block diagram which shows the process of successive interference suppression and removal in non-orthogonal multiple access. It is a figure which shows the procedure of the grant free (GF) communication in LTE. It is a figure which shows the sub-frame structure which assumed the random access of this invention. It is a figure which shows the data structure of the sub-frame structure supposing the random access of this invention. Continuous transmission method to which interleaving of the present invention is applied (Example 1) Continuous transmission method to which interleaving of the present invention is applied (Example 2)

  Hereinafter, embodiments of a wireless transmission system to which the present invention is applied will be described in detail with reference to block diagrams. In addition, about the code | symbol in a block diagram, the same code | symbol shall be used for the block with the same function unless there is special circumstances.

  The radio transmission system to which the present invention is applied has a radio frame configuration in which NOMA and GF are realized at the same time, and is transmitted without grant. There is a possibility that identification signals of a plurality of radio terminals collide at a base station. Therefore, the throughput in media access control (MAC) is performed. In addition, when applying NOMA and GF, it is important how to improve the reliability. Therefore, in addition to continuous transmission, for example, reception diversity may be performed. Since NOMA can share one radio resource by a plurality of users, the radio transmission system to which the present invention is applied implements SIC.

  FIG. 1 shows signal processing for successive interference suppression / removal in conventional radio terminals and base stations. The SIC demodulates a received signal in which signals from a plurality of wireless terminals are continuously transmitted according to the order of the received signal (for example, in descending order of received power), and subtracts the demodulated signal from the received signal. This process is repeated and all signals are demodulated and separated.

  Specifically, each wireless terminal 100 divides transmission data 1 into a terminal identification and propagation path estimation reference signal (RS1-1) and a data signal (DS1-2) for transmitting a payload. The Zadoff-chu sequence generator 2, the cyclic expander 3, and the phase shifter 4 cyclically expand the Zadoff-chu sequence for performing terminal identification, and then give a phase rotation proportional to the frequency specific to the terminal. A time signal is converted by the converter 5, a CP (common parameter) is inserted by the cyclic prefix adder 6-1, transmission processing is performed by the transmission unit 10, and transmission is performed to a predetermined base station 200.

  The transmission data transmitted from each wireless terminal 100 is subjected to reception processing by the reception unit 20, and the cyclic prefix removal unit 6-2 removes RT and DS CPs from the reception data. The discrete Fourier transform unit 21 and the Zadhoochu sequence generation unit 2 multiply the complex conjugate of the same Zadoff-chu sequence as that on the transmission side, and the inverse discrete Fourier transform unit 5 performs the conversion.

  At this time, the phase rotation by the Zadoff-chu sequence of the phase is returned, so the converted signal becomes an impulse response, but the impulse response is discriminated because there is a phase rotation proportional to a different frequency for each wireless terminal. You can do it. This is cut out for each wireless terminal by the time filter 22, and both terminal identification and acquisition of an impulse response are performed.

  The received power of each wireless terminal 100 is estimated and calculated from the channel impulse response (CIR: Channel Impulse Response) of each wireless terminal. Then, the FDE 23 performs demodulation processing using the CIR having the largest received power according to the calculated CIR. Thereafter, the signal demodulated by the error correction code decoding unit 8-2 (turbo decoding unit) is encoded with the error correction code. Thereafter, a cyclic redundancy check (CRC) check process is performed on the reception signal (RT) encoded by the CRC unit 7, and after confirming that there is no error, the received data is extracted.

  The error correction code encoder 8-3 re-encodes the received data signal demodulated and extracted with the error correction code, and the remodulator 9-3 performs the modulation process again. Then, the CIR unit 24 convolves the remodulated signal to generate a data signal that is the same as the received signal. Then, a process of subtracting the received signal equivalent to the generated identical data signal from the original received signal is performed. The FDE unit 23 performs equalization demodulation processing on the received signal of the wireless terminal having the second highest received power from the residual signal from which the same data signal has been subtracted. Repeat for received data received from.

  FIG. 2 illustrates the grant-free (GF) communication. FIG. 2 (a) shows a case where it is necessary to obtain permission from the base station 200 (BS) when the LTE radio terminal 100 (UE) transmits data. In Step 1, the radio terminal 100 A schedule request is made to. In response to this request, in Step 2, the base station 200 grants the requested schedule to the wireless terminal 100. In Step 3, the wireless terminal 100 notifies the base station 200 of the size of data to be transmitted. In Step 4, the base station 200 performs to the radio terminal 100 that necessary resources have been allocated based on the notified information such as the data size. In Step 5, the wireless terminal 100 transmits data to the base station 200.

  Processing such as resource allocation at each step between the radio terminal 100 and the base station 200 is a communication delay between the radio terminal 100 and the base station 200. The procedure until the radio terminal 100 transmits a communication request (SR: Schedule Request) to the base station eNB and the base station 200 grants permission to the radio terminal 100 is a delay of several ms, which is unacceptable in a system that emphasizes real-time characteristics. .

  Therefore, the radio transmission system to which the present invention is applied has a configuration as shown in FIG. 2B in order to avoid this delay. Since each radio terminal 100 (UE) can transmit data without obtaining permission from the base station 200 (BS), a signal (RS: Reference Signal) for identifying the radio terminal is added to the data, and the data signal (Payload) is transmitted to the base station 200. Also, this RS is used to perform propagation path estimation. Therefore, in this invention, RS becomes a structure which served as both radio | wireless terminal identification and propagation path estimation.

  FIG. 3 shows a frame configuration of a slot of a wireless transmission system to which the present invention is applied. The slot has a CP (CP: Cyclic Prefix) at the beginning and a GT (GT: Guard Time) at the end, and RS and DS are inserted between them, respectively. It is realized by combining RS and DS (DS: Data Signal) so that GF can be realized, and has a slot configuration in which a reference signal for terminal identification and channel estimation and a data signal for transmitting a payload are minimum units.

  Also, it has a 6-symbol configuration in the extended CP defined by the use of LTE, and has almost the same configuration as the LTE symbol format, and a set of two RSs and four DSs is transmitted continuously. Also, in order to realize a low delay, a mini-slot composed of two symbols of one RS and one DS in the symbol configuration using LTE is also defined. This slot realizes further reduction in delay time by reducing the number of symbols.

  FIG. 4 shows an example of details of the data structure of CP, RS, and DS. A pair of RS and DS is an area for storing data, and signal separation is processed by an interference separation algorithm. The RS is used for base station identification and CIR estimation. The RS of the present invention uses a Zadoff-chu sequence and is subjected to phase rotation so that the CIR of each wireless terminal 100 (user) can be separated on the time axis. DS separates signals by PIC or SIC using the estimated CIR.

  Next, a continuous transmission method to which interleaving of the wireless transmission system to which the present invention is applied is explained. The combination method in this continuous transmission method combines signals after FDE (FDE: Frequency Domain Equalization). Already, a weighting method is known in which the weight is adjusted based on the FDE weight calculated by the minimum mean square error (MMSE) and also using the power ratio of the channel frequency response of each antenna. It is known that this weight calculation is performed by a signal-to-noise power ratio (SNR).

  NOMA's signal separation is extended with Signal to Interference and Noise power Ratio (SINR). Here, the number of the terminal that demodulates p (maximum P units), m is the receiving antenna number (maximum M), k is the DFT point, Hp, m (k) is the k point of the mth receiving antenna of the terminal p. Is the signal power-to-interference and noise power ratio of the m-th k-point receiving antenna of the terminal p, and wp and m (k) are set as follows.

ここで、＊は複素共役を示し、ＳＩＮＲｐ、ｍ（ｋ）は

Here, * indicates a complex conjugate, and SINRp, m (k) is

となる。Ｎは雑音電力、ｐ”はＳＩＣにより干渉除去が既に終了した端末番号を示す。

It becomes. N represents noise power, and p ″ represents a terminal number for which interference cancellation has already been completed by SIC.

  In a frequency selective fading environment, SINRp, m (k) varies at each frequency point k of each wireless terminal. In contention-based communication, since a plurality of terminals access the same resource, SINR is dominated by interference signal power rather than noise power. Since the difference in SINR of each branch is very large, a selection diversity (SC) based on SINRp, m (k) is also obtained as a value that approximates the synthesis method.

  FIG. 5 shows an interleave continuous transmission system of a wireless transmission system to which the present invention is applied. The process of performing interleaving is performed by the radio terminal 100-1 and the base station 200. In the radio terminal 100, the interleaving unit 15-1 performs only the interleaving process on the continuous transmission signal (RS: Repetition Signal). On the other hand, the base station 200 first performs inverse conversion of the data interleaved by the deinterleaving unit 15-2 based on the data received from the radio terminal 100, and then performs interleaving processing again by the interleaving unit 15-1. Do.

  Interleave units 15-1 and 15-2 of radio terminal 100 and base station 200 perform interleaving, whereby a signal-to-interference noise power ratio SINRp (t) (t = 1, 2, 3,..., T) is made different between the original signal (OS: Original Signal) and the repetitive signal (RT: Repetition Signal), and the signal with different SINRp (t) is used based on the transmission signal. Are generated as continuous transmission signals, and then synthesized and executed.

  The interleaver used here varies both the power of inter-symbol interference (ISI: Inter Symbol Interference) and the power of the interference signal between the OS and RT in units of bits or symbols. In a system using NOMA, The power of the interference signal is made different by interleaving to differentiate the interference signal from the power of the residual ISI, and detection is facilitated in the subsequent processing.

  Regarding the ISI power, the FDE 23 of the MMSE standard (not shown) cannot completely remove the ISI. Therefore, the ISI power of each bit or symbol between the OS and RT of the received data by the interleave units 15-1 and 15-2. The frequency domain distortion is diffused in the time domain when the frequency domain signal with residual ISI is converted into the time domain (IDFT5). The influence of this distortion on each symbol differs depending on the transition of the symbol in addition to the fading state.

  The wireless terminal 100 generates data to be transmitted by a data generation unit 1 such as a predetermined program or application (not shown) of a device that the user possesses or uses. The CRC unit 7 performs a check process such as cyclic redundancy of the transmission data generated by the data generation unit 1 and confirms that there is no error in the transmission data.

  Then, the error correction code encoding unit 8-1 encodes the confirmed transmission data signal with the error correction code. The interleaving unit 15-1 performs the above-described interleaving processing from the encoded signal, and the modulation unit 9-1 defines the encoded signal of the error correction code in the error correction code encoding unit 8-1 as OS. Then, the signal processed by the interleaving unit 15-1 is defined as RS, and the order of bits or symbols is changed to change the shift of the symbol. Therefore, the OS and RT processing here makes the ISI power of each bit or symbol of the interleave signal different between the OS and RT.

  As for the interference signal between the signals, the MMSE-FDE can reduce the influence on the desired signal, but cannot remove the interference signal itself. Or the process which changes the electric power of a bit is performed (same in the interleave part 15-1 of BS200). On the other hand, in the case of an interference signal, the interference power of each bit or symbol of the time axis signal is changed by the weight of the FDE 23 in addition to the fading state and signal transition.

  The cyclic prefix adding unit 6-1 inserts a CP into each generated OS and RT based on the processing in the modulation unit 9-1, and continuously transmits the OS and RT as transmission data. The OS and RT structures and CP are as described above. And after the transmission process with which the radio | wireless terminal 100 is equipped, it transmits to the predetermined | prescribed base station 200 from the antenna 50-1.

  Next, the base station 200 receives, from the antenna 50-2, transmission data continuously transmitted from the radio terminal 100 (there are a plurality of radio terminals but only one is described) as reception data. The cyclic prefix removal unit 6-2 deletes the CP to which the reception data received from the radio terminal 100 is received by the antenna 50-2 provided in the base station, and the DFT unit 21 and the inverse discrete Fourier transform unit 5 perform DFT processing. Do. That is, the inverse discrete Fourier transform unit 5 performs IDFT by multiplying the complex conjugate of the same Zadoff-chu sequence as that on the transmission side. At this time, since the phase rotation by the Zadoff-chu sequence of the phase is returned, the signal after the IDFT becomes an impulse response, and there is a phase rotation proportional to a different frequency for each wireless terminal. Since it can discriminate | determine, it becomes possible to distinguish each as a signal from several each radio | wireless terminal.

  Then, by repeating this process, it is possible to cut out data for each of the plurality of wireless terminals with a predetermined time filter, and to obtain both the identification information and the impulse response of each wireless terminal included in each received data.

  The deinterleaving unit 15-2 defines the interleaved signal as RT by defining the encoded signal of the error correction code as OS in the transmitting radio terminal 100, separates the synthesized signal, and combines Unit 34 synthesizes the deinterleaved receive RT LLR and OS LLR.

  The error correction code decoding unit 18 performs equalization and demodulation of the received data based on the signal characteristics of the received power of the received data. For example, the error correction code decoding unit 18 determines the signal characteristics of the received power of the received data, and equalizes and demodulates the signal having the strongest power among the received data. The data to be transmitted is output after combining the demodulated transmission signal and continuous transmission signal.

  The error correction code decoding unit 8-2, the interleaving unit 15-1, and the remodulation unit 9-3 perform the same error correction code code processing as described above on the basis of the signal included in the received data after output. The interleaving process and the remodulation process are sequentially performed. It is confirmed by CRC7 that there is no error, and the demodulated signal is encoded again with the error correction code by the error correction code encoder 8-3, again subjected to interleaving, remodulation and CIR convolution, and the same To generate data.

  This is subtracted from the original received signal, and then the process returns to the above-described processing to remove the signal that causes interference with the next signal. It is repeatedly performed for the wireless terminal having the second highest received power (in descending order of signal-to-interference power SIR) from the residual signal from which the same data signal is removed. And it implements with respect to all the reception data, and complete | finishes the process of the reception data from several radio | wireless terminals.

  Thereby, it becomes possible to further improve the reliability. In continuous transmission using interleaving, interleaving is performed to change the signal-to-interference noise power ratio SINRp (t) (t = 1, 2, 3,..., T) of each symbol in the time axis signal to the original signal (OS : Original Signal (RT) and repetitive signal (RT) can be made different, so it is possible to obtain a diversity effect by synthesizing signals with different SINRp (t). . The interleaver used here has an effect of making both the power of inter-symbol interference (ISI) and the power of the interference signal different between the OS and RT in units of bits or symbols. Therefore, in a system using NOMA, interleaving has a greater effect of making the power of the interference signal different than that of residual ISI.

  FIG. 6 shows the interleave continuous transmission system of the present invention. This embodiment relates to communication between a plurality (two) of the radio terminal 100 and the base station 200, and two antennas are installed in the base station 200, and data from the radio terminal 100 is transmitted using these two antennas. Receive.

  The process of performing the interleaving is the same as that of the wireless terminal 100 and the base station 200, and the wireless terminal 100 also performs an interleaving process on the RT by the interleaving unit 15-1, and adds the modulation unit 9-1 and the cyclic prefix. After the processing in the unit 6-1, the OS and RT are continuously transmitted to insert the CP, and after the transmission processing (not shown) provided in the wireless terminal, the antenna 50-1 transmits a predetermined base station 200. Send.

  The base station 200 performs transmission data reception processing in the same manner as the above-described combining method and the interleaved continuous transmission method described in FIG. 5, but the composition of the combining method is added and the MMSE unit of the base station 200 is added. 26, based on the FDE weight calculated by the minimum mean square error, the power ratio of the channel frequency response of each antenna 50-2, 50-3,. Then, it is repeatedly performed on the received data from a plurality of wireless terminals.

  Thereby, simultaneous connection from a plurality of radio terminal stations to the base station becomes possible, and the probability of successful signal separation when interference suppression removal is performed by the PIC in the base station increases.

  In the wireless transmission method according to the present embodiment, the transmission data from the plurality of wireless terminals 100 described above is transmitted from the data to be transmitted, and the plurality of wireless terminals 100 based on the transmission signal. And a second step of continuously transmitting the generated transmission signal and the continuous transmission signal as transmission data and transmitting them to the base station 200.

  The base station 200 receives, as received data, transmission data continuously transmitted by the plurality of radio terminals 100, and the received data according to the order of the signal characteristics of the received power of the received data, etc. A fourth step of outputting the transmission target data after synthesizing and demodulating the demodulated transmission signal and continuous transmission signal, and using the output transmission target data as a reproduction transmission signal, 5th process which produces | generates a continuous transmission signal as a reproduction | regeneration continuous transmission signal based on the said reproduction | regeneration transmission signal, The reception data which becomes the same as the data reproduced | regenerated from the said reproduction | regeneration transmission signal and reproduction | regeneration continuous transmission signal from the said received data And at least a sixth step of performing a series of processes related to the output of the data to be transmitted on the other received data according to the order of the signal characteristics.

  Similar to the contents described above, communication processing that achieves both a large number of connections and a low delay becomes possible. As a result, even if a collision occurs in signals transmitted from the plurality of terminals 100, low delay and communication quality are ensured, and even if the number of simultaneous connections increases, highly reliable shared communication is possible.

DESCRIPTION OF SYMBOLS 1 Transmission data 1-1 Reference signal 1-2 Data signal 2 Zadhoochu series generation part 3 Cyclic expander 4 Phase shift part 5 Inverse discrete Fourier transform part 6-1 Cyclic prefix addition part 6-2 Cyclic prefix removal part 7 CRC unit 8, 8-1, 8-3 Error correction code encoding unit 8-2 Error correction code decoding unit 9-1 Modulating unit 9-2 Inverse modulating unit 9-3 Remodulating unit 10 Root Lay cosine filter unit 15 -1 Interleaving unit 15-2 Inverse interleaving unit 21 Discrete Fourier transform unit 22 Time filter 23 FDE unit 24 CIR unit 26 MMSE unit 33 LLR unit 34 Combining unit 35 Sequential interference removing units 50-1, 50-2, 50-3 Antenna 100 Wireless equipment (User Equipment)
200 Base Station

Claims (6)

A wireless transmission system for receiving transmission data from a plurality of wireless terminals at a common base station,
The plurality of wireless terminals are:
Means for generating a transmission signal from data to be transmitted and a continuous transmission signal based on the transmission signal;
Means for continuously transmitting the generated transmission signal and continuous transmission signal as transmission data, and transmitting to the base station;
Comprising at least
The base station
Means for receiving transmission data continuously transmitted by the plurality of wireless terminals as reception data;
Means for equalizing and demodulating the received data based on signal characteristics of the received data, and outputting the data to be transmitted after combining the demodulated transmission signal and continuous transmission signal;
Means for generating a transmission signal as a reproduction transmission signal using the output data to be transmitted and a continuous signal as a reproduction continuous signal based on the reproduction transmission signal;
From the received data, the same data as the data reproduced from the reproduced transmission signal and the reproduced continuous transmission signal is subtracted, and a series of output of the transmission target data to other received data according to the order of the signal characteristics Means for performing
Having at least
Wireless transmission system characterized by   2. The wireless transmission system according to claim 1, wherein the signal characteristic of the reception data is an output strength of reception power.   3. The radio transmission system according to claim 1, wherein the signal characteristic is such that both the power of intersymbol interference and the power of the interference signal are different in bit or symbol units.   4. The radio transmission system according to claim 1, wherein each of the signals includes a terminal identification area, a channel estimation area, and a payload carrying area.   The base station further includes a plurality of antennas, receives transmission data continuously transmitted from a plurality of terminal stations, performs weighting based on the power ratio of the channel frequency response of each antenna, The wireless transmission system according to claim 1, wherein the wireless transmission system is synthesized. A wireless transmission method for receiving transmission data from a plurality of wireless terminals at a common base station,
The plurality of wireless terminals are:
A first step of generating a transmission signal from the transmission target data and a continuous transmission signal based on the transmission signal;
A second step of continuously transmitting the generated transmission signal and the continuous transmission signal as transmission data and transmitting to the base station;
Comprising at least
The base station
A third step of receiving transmission data continuously transmitted by the plurality of wireless terminals as reception data;
A fourth step of equalizing and demodulating the received data according to the order of the signal characteristics of the received power of the received data, and outputting the data to be transmitted after combining the demodulated transmission signal and continuous transmission signal;
Using the output data to be transmitted, a fifth step of generating a transmission signal as a reproduction transmission signal and a continuous transmission signal as a reproduction continuous transmission signal based on the reproduction transmission signal;
The received data that is the same as the data reproduced from the reproduction transmission signal and the reproduction continuous signal is subtracted from the received data, and the output of the transmission target data is applied to other reception data according to the order of the signal characteristics. A sixth step for performing a series of processes;
Having at least
A wireless transmission method characterized by the above.

Images