RU154283U1 - WIRELESS COMMUNICATION DEVICE, ALLOWING TO TRANSMIT AND RECEIVE INFORMATION IN ONE FREQUENCY BAND - Google Patents

Abstract

A wireless communication device that allows simultaneous transmission and reception of information in one frequency band, comprising: an information input, which is the input of the device, an information output, a digital-to-analog conversion unit, a first frequency conversion unit, the input of which is connected to the output of the digital-to-analog conversion unit, a transmitting antenna, a receiving antenna an antenna, a second frequency conversion unit, an analog-to-digital conversion unit, the input of which is connected to the output of the second frequency conversion unit, I distinguish in that the signal conditioning unit is additionally introduced into it, the input of which is the information input of the device, and the first output of the signal forming unit is connected to the input of the digital-to-analog conversion unit, the first amplifier whose input is connected to the output of the first frequency conversion unit, the first filter whose input connected to the output of the first amplifier, and the output connected to the input of the transmitting antenna, a phase shifter, the input of which is connected to the output of the first amplifier, the first delay unit, the input of which is connected nen with the output of the phase shifter, the attenuation unit, the input of which is connected to the output of the first delay unit, the second filter, the input of which is connected to the output of the receiving antenna, the first adder, the first input of which is connected to the output of the attenuation unit, and the second input is connected to the output of the second filter, the second an amplifier whose input is connected to the output of the first adder, and the output is connected to the input of the second frequency conversion unit, the second delay unit, the input of which is connected to the first output of the analog-to-digital converter, channel estimation unit

Description

The utility model relates to radio communications, and can be used in the development of wireless communication systems.

A known wireless communication device described in the description of the invention under the name "Radio communication system with a relay" [1]. The device comprises cascade-connected switching and interface unit, a modulator, a transmitter, a filter having two outputs, the first of which is connected to the input of the transceiver antenna, and the second to the input of the receiver, and two inputs, the first of which is connected to the output of the transmitter, and the second with the output of the transceiver antenna, a demodulator whose input is connected to the output of the receiver, and the output with the input of the control and pairing unit. The data rate depends on the width of the used frequency band, and the type of modulation used. The disadvantage of this device is that this device operates in duplex mode (temporary or frequency), so the allocated frequency-time resource is used only by 50%, which in turn reduces the potential transmission rate of information.

Closest to the claimed device is a device for receiving and transmitting OFDM signals with increased noise immunity [2]. The prototype device consists of a series-connected: an interleaver-encoder, the input of which is an input of a device, a symbol mapper and a pilot signal generation unit, connected in series: a pseudo-random phase modulation subcarrier block, an inverse Fourier transform calculation unit, a guard interval insertion unit, a digital-to-analogue conversion unit, I / Q modulator-frequency converter and transmitting antenna, connected in series: receiving antenna, I / Q demodulator-frequency converter, bl as an analog-to-digital conversion, a direct Fourier transform calculation unit, a channel parameter estimation and correction unit, a symbol demaper and a noise-resistant decoder-deinterleaver, the output of which is the information output of the device, a signal-to-noise ratio calculation unit, and a subcarrier phase demodulator, the output of the pilot formation unit -signals is connected to the first input of the pseudo-random phase modulation subcarrier block, the output of the direct Fourier transform calculation unit is connected to the first input sub-carrier demodulator, the input of the signal-to-noise ratio calculation unit is connected to the input of the I / Q demodulator-frequency converter, and the output is connected to the second input of the sub-carrier pseudo-random phase modulation unit and to the second input of the sub-carrier phase demodulator, the third input of the sub-pseudo-random phase modulation subcarrier is a device signaling data input, and a subcarrier phase demodulator output is a device signaling data output. The disadvantage of the prototype device is that this device operates in duplex mode (temporary or frequency), thus, the allocated frequency-time resource is used only by 50%, which in turn reduces the potential transmission rate of information.

The task to which the proposed technical solution is directed is to increase the speed of information transfer, achieved due to the fact that the proposed device performs the simultaneous transmission and reception of signals in the same frequency band, which allows the most efficient use of the allocated time-frequency resource.

The solution to this problem is achieved by the fact that in the known device, comprising: an information input, which is the input of the device, information output, digital-to-analog conversion unit, a first frequency conversion unit, the input of which is connected to the output of the digital-to-analog conversion unit, a transmitting antenna, a receiving antenna, and a second a frequency conversion unit, an analog-to-digital conversion unit, the input of which is connected to the output of the second frequency conversion unit, an additional signal conditioning unit is introduced s, whose input is the information input of the device, and the first output of the signal conditioning unit is connected to the input of the digital-to-analog conversion unit, the first amplifier, the input of which is connected to the output of the first frequency conversion unit, the first filter, the input of which is connected to the output of the first amplifier, and the output is connected to the input of the transmitting antenna, the phase shifter, the input of which is connected to the output of the first amplifier, the first delay unit, the input of which is connected to the output of the phase shifter, the attenuation unit, the input of which is connected the output of the first delay unit, the second filter, the input of which is connected to the output of the receiving antenna, the first adder, the first input of which is connected to the output of the attenuation unit, and the second input is connected to the output of the second filter, the second amplifier, the input of which is connected to the output of the first adder, and the output connected to the input of the second frequency conversion unit, the second delay unit, the input of which is connected to the first output of the analog-to-digital converter, the radio wave propagation channel estimator, the first input of which is connected to the first the course of the signal generation unit, and the second input with the second output of the analog-to-digital conversion unit, a buffer memory device, the input of which is connected to the output of the radio wave propagation channel estimator, the compensation signal generation unit, the first input of which is connected to the output of the buffer memory, and the second input connected to the second output of the signal conditioning unit, a second adder, the first input of which is connected to the output of the second delay unit, and the second input of which is connected to the output of the pho block the compensation signal, a signal demodulation unit, the input of which is connected to the output of the second adder, and the output of which is the information output of the device.

Functional diagram of the proposed device is shown in FIG. 1, on which is indicated: 1 - information input of the device, 2 - signal generation unit, 3 - digital-to-analog conversion unit, 4, 15 - first and second frequency conversion units, 5, 14 - first and second amplifiers, 6, 12 - first and second filters, 7 - transmitting antenna, 8 - phase shifter, 9 - first delay unit, 10 - attenuation unit, 11 - receiving antenna, 13, 21 - first and second adder, 16 - analog-to-digital conversion unit, 17 - block estimates of the radio wave propagation channel, 18 — buffer memory, 19 — compensating generation unit signal, 20 - second delay unit, 22 - signal demodulation unit, 23 - information output of the device.

Detailed description of the device.

Traditionally, communication systems use the duplex separation of transmitted and received information, time or frequency. With full duplex, data is transmitted and received simultaneously in the same frequency band, which will double the data transfer rate due to more efficient use of the time-frequency resource. The implementation complexity lies in the fact that the signal power at the output of the transmitting antenna 7 is significantly higher than the power of the received signal from the remote receiving and transmitting point in the receiving antenna 11, thus, the receiving path will be clogged with its own transmitted signal. For the full-duplex communication system to function normally, isolation of about 100 dB is necessary for the honey transmitting 7 and receiving 11 antenna of each transceiver point. In order for full-duplex communication to become feasible, it is necessary to compensate for the own transmitted signal in the receiving path. In the conditions of a multipath channel of propagation of radio waves (RRV), the receiving antenna 11 will receive not only a direct signal from the output of the antenna 7, but also signals reflected from various surrounding objects. To compensate for the reflected signals, it is necessary to evaluate the communication channel between the transmitting antenna 7 and the receiving antenna 11.

To describe the operation of the device, we introduce the following notation:

- “Pilot signal” - a pre-known signal used to evaluate the PPB channel.

- "Interference signal" - a communication signal intended for a remote receiving point, radiated by a transmitting antenna 7, also received in the receiving antenna 11.

- "Useful signal" - a connected signal from a remote transmitting point, received by the receiving antenna 11,

Initially, the RRV channel is estimated between the transmitting 7 and receiving 11 antennas of the device. Signal generating unit 2 generates a “pilot signal”, from the output of signal generating unit 2, the “pilot signal” is fed to the input of the digital-to-analog conversion unit 3, to the first input of the estimator of the radio wave propagation channel 17, and also to the second input of the compensating forming unit signal 19. From the output of the digital-to-analog conversion unit 3, the signal sequentially passes through the first frequency conversion unit 4, and the first amplifier 5, from the output of the last “pilot signal”, is fed to the input of the first filter 6 and then transmitted antenna 7. Also, the "pilot signal" from the output of the first amplifier 5 is fed to the input of the phase shifter 8, then to the input of the first delay unit 9. From the output of the first delay unit 9, the "pilot signal" is fed to the input of the attenuation unit 10. Phaser, first block delays and attenuations are configured (in manual or automatic mode), so that the signal transmitted through these blocks and received at the first input of the first adder 13 coincides in power and delay with the signal received at the second input of the adder 13, but it is out of phase , one hundred the purpose to compensate possible direct signal emitted by the antenna 7 and received by the receiving antenna 11.

Radiated by the transmitting antenna 7, the “pilot signal”, passing through the multipath channel of propagation of radio waves, is received by the receiving antenna 11, is fed to the input of the second filter 12, where the received signals are filtered, and the signals of a given frequency band are extracted.

Next, the "pilot signal" sequentially passes through the adder 13, where direct beam compensation is performed, the second amplifier 14, the second frequency conversion unit 15, the analog-to-digital conversion unit 16. From the first output of the analog-to-digital conversion unit 16, the "pilot signal" is input the second delay block 20, and from the second output of block 16, the “pilot signal” is fed to the second input of the estimator of the radio wave propagation channel 17. In block 17, according to the original “pilot signal” and “pilot signal” that passed the radio wave propagation channel, forms an estimate of the propagation channel of the radio waves (estimation of the transfer function and impulse response) is made between the transmitting antenna 7 and the receiving antenna 11, taking into account the compensation of the direct beam after summing in block 13. The operation of block 17 (the block for estimating the propagation channel of radio waves) is disclosed in the description of the utility model No. 115591 “Device for evaluating the transfer function of the radio wave propagation channel”. In this utility model, an estimate of the propagation channel of radio waves is made by the “pilot signal”, in digital form. Evaluation of the RRV channel can be performed by any known method, for example [3]. The estimate of the impulse response of the RRV channel obtained in block 17 is denoted by h (m). The RRV channel estimate obtained in block 17 is stored in the buffer storage device 18; it is necessary at subsequent stages to form a compensating signal in block 19, to eliminate the reflections of the “interference signal” caused by the multipath of the RRV channel, as well as the direct beam energy left after the analog compensation.

After receiving an estimate of the RRV channel, between the transmitting 7 and receiving 11 antennas of the device, a connection is established with the remote receiving and transmitting point and the transmission and reception of information signals begins. The input of the device 1 receives an information signal, in the signal generation unit 2, the information signal is processed (noise-resistant coding, interleaving, modulation). At the output of the signal generating unit 2, a discrete signal S1 (m) is formed, where m is the reference number of the discrete sequence. The signal S1 (m) is input to the digital-to-analog conversion unit 3, where the signal is converted to analog form. Next, the signal S1 (t) is fed to the input of the first frequency conversion unit 4, here the signal is transferred to the carrier frequency, after which the signal is amplified A times in the first amplifier 5:

S _gain (t) = A · S1 (t) · sin (2πft + φ) + n,

where S1 (t) is the modulated information signal,

f is the carrier frequency of the signal,

φ is the initial phase,

t is the time

n is the noise.

The output of the first amplifier 5 S _GAIN (t) signal passes through the first filter 6, and then input to the transmitting antenna 7, which is emitted by the remote transceiver transmitting point. However, the signal from the transmitting antenna 7, through the propagation medium, by means of electromagnetic waves, also enters the receiving antenna 11 of this device. Since the proposed device operates in full duplex mode, i.e. the signal is transmitted to a remote receiving center, as well as the reception of signals from a remote transmitting station is carried out simultaneously, in the same frequency band, then the own signal from the transmitting antenna 7 to the receiving antenna 11 of the proposed device creates significant interference with the reception of the “useful signal” from the remote receiving and transmitting point, since the power of its own "interference signal" by tens of dB exceeds the power of the useful information signal from a remote transmitting point. Thus, in the receiving antenna, the total signal S _pr (t) is received: the sum of the “useful signal” from the remote transmitter S _field (t), and the “interference signal” S _pom (t). If there is a multipath propagation channel, radio signals will also be received at the receiving antenna.

S _ol (t) = S _pom (t) + S _floor (t) + n,

S _pom (t) = S _{pom_pr} (t) + _{S pom_pr} (t),

S _{pom_pr} (t) = A1 ₀ S1 (t) sin (2πft + φ1 ₀ ) + n,

S _floor (t) = S _{field_pr} (t) + S _{field_prot} (t)

S _{pol_pr} (t) = A2 ₀ S2 (t) sin (2πft + φ2 ₀ ) + n,

S _{pol_pr} - direct "signal-interference",

S _pomotr - reflections "signal-interference" caused by the multipath of the PPP channel,

S _{pol_pr} - direct "useful signal",

S _{pol_opr} - reflections of the "useful signal" caused by the multipath channel RRV,

A1 ₀ - the amplitude of the direct "signal-interference"

A1 _i - the amplitude of the i-th re-reflected "interference signal",

l is the number of reflected "interference signals",

A2 ₀ - the amplitude of the direct "useful signal",

A2 _j - the amplitude of the j-th re-reflected "useful signal",

k is the number of reflected "useful signals",

S1 (t) is a modulated information signal at the output of the digital-to-analog conversion unit 3 of the proposed device,

S2 (t) is the modulated information signal of the remote transmitter,

f is the carrier frequency of the signal,

φ1 ₀ - the initial phase of the direct "signal-interference",

φ1 _i - the initial phase of the i-th re-reflected "interference signal",

φ2 ₀ - the initial phase of the direct "useful signal",

φ2 _j - the initial phase of the j-th re-reflected "useful signal",

τ1 _i is the delay of the i-th re-reflected "interference signal" relative to the direct "interference signal",

τ2 _j is the delay of the jth re-reflected "useful signal" relative to the direct "interference signal",

where A1 >> A2. To demodulate the “wanted signal”, it is necessary to eliminate the effect of the “interference signal”. For this, the signal S _gain (t) from the output of the first amplifier 5 is fed to the input of the phase shifter 8, after which the signal passes sequentially through the block of the first delay unit 9 and the attenuation unit 10. At the output of the attenuation unit 10, a "compensating signal" is generated. The delay and attenuation of the signal in blocks 9 and 10 are made in such a way that the compensating signal matches the “interference signal” as precisely as possible, but is out of phase. Compensation of the "interference signal" is made in the first adder 13. The signal S _comp (t) is received at the first input of the first adder 13, the signal S _pr (t) is received at the second input of the first adder 13, received by the receiving antenna 11 and passed through the second filter 12

, то прямой "сигнал-помеха" S_{пом_пр}(t) и компенсирующий сигнал S_комп(t) практически полностью исключат друг друга, таким образом, на выходе первого сумматора 13 имеем сигнал S_пр1(t),If

, then the direct "signal-to-noise" S _{pom_pr} (t) and the compensating signal S _comp (t) are almost completely excluded from each other, thus, at the output of the first adder 13 we have a signal S _pr1 (t),

S _pr1 (t) = S _{p_op} (t) + S _{p_p} (t) + S _{p_p} (t) + n,

To maximize the elimination of the received reflections of the "interference signal" caused by the multipath of the RRV channel, additional digital processing is carried out.

From the output of the first adder 13, the signal S _pr1 (t), is fed to the input of the second amplifier 14, where the signal is amplified, and then fed to the input of the second frequency conversion unit 15, from where to the input of the analog-to-digital conversion unit 16. Denote the digitized signal as S _pr1 (m).

S _pr1 (m) = S _{p_op} (m) + S _{p_p} (m) + S _{p_p} (m) + n,

S _{pomp_image} (m) is the signal corresponding to the signal S _{pomp_image} (t) after amplification, frequency conversion and digitization,

S _{pol_pr} (m) is the signal corresponding to the signal S _{pol_pr} (t), after amplification, frequency conversion and digitization,

S _{pol_opr} (m) is the signal corresponding to the signal S _{pol_opr} (t), after amplification, frequency conversion and digitization,

From the output of the analog-to-digital conversion block 16, the signal S _pr1 (m) is input to the second delay block 20. In block 19, a compensating signal is generated based on the signal generated in block 2 and the channel estimate of the PPB stored in block 18. Compensating signal S _comp (m) can be written as follows: S _comp (m) = ifft (fft (S1 (m)) · fft (h (m))), where: fft is the forward fast Fourier transform operation, ifft is the inverse fast operation Fourier transform. The second delay unit 20 is used so that the inputs to the first and second inputs of the second adder are synchronized. From the output of block 19, the compensating signal S _comp (m) is supplied to the second input of the second adder 21, where it is added to the signal S _pr (m). The compensating signal S _comp (m) from the output of block 19, almost completely repeats the signal S _pomotr (m), but is in antiphase with it. Thus, the compensation of the "signal-interference", S _pomotr (m), caused by the multipath channel RRV. We write the signal S _CR2 (m), at the output of the second adder 21:

S _pr 2 (m) = S _{pol_pr} (m) + S _{pol_prot} (m) + n,

From the output of the second adder 21, the signal S _pr2 (m) is fed to the input of the signal demodulation unit 22, where demodulation (decoding, deinterleaving) is performed, and the information sequence is extracted, which is fed to the information output 23 of the proposed device. The evaluation of the PPP channel between the transmitting antenna 7 and the receiving antenna 11 of the proposed device should be repeated periodically, the repetition rate depends on the rate of change of the PPP channel (coherence time). The operations described above make it possible to obtain an isolation between the transmitting and receiving paths of the order of 100 dB, which is achieved due to analog compensation of the “interference signal”, digital compensation produced after analog-to-digital conversion, and also due to the physical diversity of the receiving 7 and transmitting 11 antennas the proposed device.

Increasing the speed of information transfer is achieved due to the device operating in full duplex mode (simultaneous transmission and reception of information in one frequency band), which allows the most efficient use of the allocated time-frequency resource, and can reach from 1.5 to 2 times, compared with the device prototype.

1. Pat. RF №2371852, IPC H04B 7/24. Radio communication system with a repeater. Publ. 10/27/2009

2. Pat. RF №2423002, IPC H04J 13/00. A device for receiving and transmitting OFDM signals with increased noise immunity. Publ. 02/20/2010

3. E.P. Voroshilin, E.V. Rogozhnikov, A.S. Vershinin, Method for improving the accuracy of estimating the transfer function of a radio wave propagation channel / Bulletin of Tomsk Polytechnic University. 2011.V. 319. No. 5, p. 133-137.

Claims (1)

A wireless communication device that allows simultaneous transmission and reception of information in one frequency band, comprising: an information input, which is the input of the device, an information output, a digital-to-analog conversion unit, a first frequency conversion unit, the input of which is connected to the output of the digital-to-analog conversion unit, a transmitting antenna, a receiving antenna an antenna, a second frequency conversion unit, an analog-to-digital conversion unit, the input of which is connected to the output of the second frequency conversion unit, I distinguish in that the signal conditioning unit is additionally introduced into it, the input of which is the information input of the device, and the first output of the signal forming unit is connected to the input of the digital-to-analog conversion unit, the first amplifier whose input is connected to the output of the first frequency conversion unit, the first filter whose input connected to the output of the first amplifier, and the output connected to the input of the transmitting antenna, a phase shifter, the input of which is connected to the output of the first amplifier, the first delay unit, the input of which is connected nen with the output of the phase shifter, the attenuation unit, the input of which is connected to the output of the first delay unit, the second filter, the input of which is connected to the output of the receiving antenna, the first adder, the first input of which is connected to the output of the attenuation unit, and the second input is connected to the output of the second filter, the second an amplifier whose input is connected to the output of the first adder, and the output is connected to the input of the second frequency conversion unit, the second delay unit, the input of which is connected to the first output of the analog-to-digital converter, channel estimation unit radio wave propagation, the first input of which is connected to the first output of the signal conditioning block, and the second input to the second output of the analog-to-digital conversion unit, a buffer memory device, the input of which is connected to the output of the radio wave propagation channel estimator, the compensation signal generating block, the first input of which is connected with the output of the buffer memory, and the second input is connected to the second output of the signal generation unit, the second adder, the first input of which is connected to the output of the second nth delay unit, and the second input of which is connected to the output of the compensating signal generating unit, the signal demodulation unit, the input of which is connected to the output of the second adder, and whose output is the information output of the device.

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