JP4749297B2 - Wireless transmission apparatus and wireless transmission method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve a reception quality by suppressing interference in a UWB-MIMO (Ultra Wide Band)-(Multi-Input Multi-Output) transmission system and to improve throughput of the system. <P>SOLUTION: A frame constitution section 301-1, 301-2 constitutes a frame containing a timing detection symbol, a pilot symbol and a data symbol. A modulation section 302-1, 302-2 performs modulation processing on framed digital data. A radio section 303-1, 303-2 performs frequency conversion on a modulated signal for radio transmission and transmits a transmission signal from a transmission antenna ANT1, ANT2 in a transmission timing set by a timing setting section 304. The timing setting section 304 sets the transmission timing of the transmission signal on the basis of a timing control value indicating the deviation of a reception timing detected in a radio reception apparatus of a communicating party and instructs the transmission timing to the radio section 303-1, 303-2. <P>COPYRIGHT: (C)2007,JPO&amp;INPIT

Description

  The present invention relates to a wireless transmission device and a wireless transmission method, and more particularly to a wireless transmission device and a wireless transmission method for transmitting a modulated signal using a plurality of antennas.

  Conventionally, a method of performing high-speed wireless communication using an extremely wide frequency band of about several GHz, such as a transmission method called UWB (Ultra WideBand) described in Non-Patent Document 1, has been studied. .

  As a transmission signal at this time, a method of directly transmitting a pulse signal instead of modulating a carrier wave using a baseband signal as in normal wireless communication has been proposed. In this case as well, there is a method that uses a high-frequency signal corresponding to a carrier wave in normal wireless communication, but this high-frequency signal is not generated continuously but only when a pulse signal exists. Therefore, as described above, it is general to express that a pulse signal is transmitted directly or a carrier wave is not used. This method has the advantages of low cost and low power consumption.

Hereinafter, this UWB transmission system will be described with reference to FIG. FIG. 29A is a diagram illustrating an example of a pulse signal having a time waveform width of 1 ns or less, and FIG. 29B is a diagram illustrating a corresponding power spectrum. As an example, if the signal cycle is 1 ns (1 ns = 1.0 x 10 ^-9 s) and 1-bit information is transmitted with each pulse signal, the transmission speed is 1 / (1 x 10 ^-9 ) = 1.0 x 10 ⁹ = 1 Gbps. By demodulating this transmission signal on the receiving side, high-speed wireless communication is possible. At this time, the power spectrum is distributed over several GHz.

  As another method for improving the transmission speed, for example, a different modulation signal is transmitted from a plurality of antennas as in a transmission method called MIMO (Multi-Input Multi-Output) described in Non-Patent Document 2, There has been proposed a method for improving the transmission rate without expanding the frequency band by separating and demodulating the modulated signals transmitted from the antennas simultaneously on the receiving side.

  Hereinafter, this MIMO transmission system will be described with reference to the drawings. As shown in FIG. 30, a case is considered in which modulated signals A and B are simultaneously transmitted from two transmitting antennas ANT1 and ANT2, and modulated signals A and B are received by two receiving antennas ANR1 and ANR2. In this case, it is necessary to estimate four channel fluctuations h11 (t), h12 (t), h21 (t), and h22 (t) on the receiving side.

Therefore, as shown in FIG. 30, pilot symbols (radio wave propagation environment estimation) for estimating channel fluctuations h11 (t), h12 (t), h21 (t), and h22 (t) in modulated signals A and B. Symbols) 01, 02, 03, 04 are arranged. The known signal here the pilot symbols 01, 03 are transmitted simultaneously C, and the known signal of -C Pilot symbol 02 ^*, and sends a known signal of the pilot symbol 04 ^{C *.} Incidentally, * indicates a conjugate complex number. In addition, data symbols other than pilot symbols 01, 02, 03, 04 are arranged in both modulation signal A and modulation signal B.

  In this way, in a wireless transmission device that simultaneously transmits different modulation signals from a plurality of antennas, by embedding pilot symbols in the modulation signals transmitted from each antenna, the modulation signal synthesized on the propagation path can be satisfactorily received on the receiving side. It can be separated and demodulated. As described above, the transmission rate can be improved without expanding the frequency band.

Furthermore, Non-Patent Document 1 proposes a method for further improving the transmission rate by the UWB-MIMO transmission method that combines the UWB transmission method and the MIMO transmission method. The transmission method in Non-Patent Document 1 reduces inter-symbol interference and inter-chip interference due to multipath by transmitting different signals from multiple antennas “simultaneously” and performing MMSE (Minimum Mean Square Error) detection on the receiving side. It has been shown that you can.
“MMSE Detection for High Date Rate UWB-MIMO Systems” IEEE VTC2004-Fall, pp.1463-1467, September 2004 "Proposal of SDM-COFDM system for wideband mobile communication realizing 100Mbit / s with MIMO channel" IEICE, IEICE Technical Report RCS-2001-135, October 2001

  However, a conventional wireless transmission method (for example, one symbol time of a wireless LAN standard defined by IEEE802.11) such as a UWB transmission method that transmits and receives one symbol time (the time occupied by one pulse signal) in the ns or ps order. In the case of a wireless transmission system using a short symbol time compared to several ms), the influence of the difference in arrival time until transmission signals from a plurality of transmission antennas reach one reception antenna becomes relatively large. . In general, the difference in arrival time increases, and accordingly, the greater the difference in arrival time in one symbol time, the less accurately multiplexed in the MIMO transmission scheme. In other words, one signal is an interference signal for the other signal. For this reason, the reception quality of the UWB-MIMO transmission method is degraded.

FIG. 31 is a diagram for explaining this problem. FIG. 31A shows a case where the symbol length Ts_long is sufficiently longer than the propagation delay time, and FIG. 31B shows a case where the symbol length Ts_short is not much different from the propagation delay time. In order to simplify the description, Ts_long = 1 μs, Ts_short = 1 ns, and two transmission antennas (ANT1, ANT2) and one reception antenna (ANR1) will be described. The propagation channels from ANT1 and ANT2 to ANR1 are h11 and h12, and the delay times are T11 and T12, respectively. Here, since the delay times T11 and T12 are values determined by the path length of the propagation channel, they do not depend on the symbol length of the modulated signal to be transmitted. In the case of FIG. 31A, since the difference ΔTr1 between T11 and T12 is shorter than the symbol length Ts_long, the degradation of reception quality due to ΔTr1 is small. However, as shown in FIG. 31B, when the symbol length Ts_short does not change much compared to ΔTr1, the reception quality deteriorates due to ΔTr1. As an example, if the difference between the propagation channels h11 and h12 is 1 m, {1 [m] / (3.0 × 10 ⁸ [m / s])} × 1.0 × 10 ⁻⁹ [s → ns] = 3.3 ns It becomes longer than the symbol length Ts_short.

  The present invention has been made in view of the above points, and provides a wireless transmission device and a wireless transmission method capable of improving reception quality by suppressing interference and improving system throughput in a UWB-MIMO transmission system. For the purpose.

In order to solve this problem, the wireless transmission device of the present invention provides a plurality of antennas and a pulse signal , which is a timing detection symbol used for detection of reception timing in a communication partner device, to data transmitted from each antenna. A frame configuration unit configured to insert and configure a frame; a timing setting unit configured to set a transmission timing based on a reception timing shift detected in the communication partner device; and a transmission timing set by the timing setting unit, The configuration means comprises transmission means for transmitting data framed by each antenna from each antenna.

Also, the wireless transmission method of the present invention is a wireless transmission method for transmitting data from a plurality of antennas, and is used for timing detection used for detecting reception timing in a communication partner apparatus for data transmitted from the antennas. Frame setting step for configuring a frame by inserting a pulse signal that is a symbol , a timing setting step for setting a transmission timing based on a shift in reception timing detected in the communication counterpart device, and setting in the timing setting step A transmission step of transmitting the data framed in the frame configuration step from each of the antennas at a transmission timing and a method comprising the transmission step are employed.

  According to the present invention, in the UWB-MIMO transmission system, the transmission timing of the pulse signal transmitted from each transmission antenna can be adjusted according to the propagation delay time and the like, so that the reception quality can be improved by suppressing interference. Throughput can be improved. In addition, since the transmission timing is simply changed on the transmission side in advance according to the difference in reception timing instead of performing complicated timing adjustment, the reception timing can be controlled with a simple configuration.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the pulse signal used in the following description is a technical term generally used in wireless communication. However, in this embodiment, the form of the pulse signal is not limited unless otherwise specified. Therefore, an impulse signal, a square pulse signal, a Gaussian pulse signal, or the like can be used as the pulse signal. In addition, an operation performed on a pulse signal in order to put information on the pulse signal is called modulation, and a generated signal is called a modulation signal. At this time, a pulse signal which is a non-modulated signal is included in a signal called a modulated signal in the following description. Further, the UWB system includes a monocycle pulse system, an impulse system with a carrier, a system using an OFDM system, and the like, and the present invention is not limited to a specific UWB system. Further, the present invention can be implemented without being limited to the data modulation method (for example, OOK (On-Off Keying), ASK (Amplitude Shift Keying), PSK (Phase Shift Keying), etc.) in each of the above methods.

(Embodiment 1)
FIG. 1 is a basic configuration diagram of a radio transmission apparatus and radio reception apparatus according to Embodiment 1 of the present invention. As illustrated in FIG. 1, the wireless transmission device 100 includes a frame configuration unit 101, a timing setting unit 102, and a plurality of transmission antennas ANT1 to ANTm. The frame configuration unit 101 configures a transmission frame of a pulse signal (pulse signal 1 to pulse signal m) transmitted using a plurality of transmission antennas ANT1 to ANTm. The timing setting unit 102 sets the transmission timing of the pulse signal (pulse signal 1 to pulse signal m).

  In addition, the wireless reception device 150 includes a plurality of reception antennas ANR1 to ANRn and a timing detection unit 151. The timing detection unit 151 detects a reception timing shift, and feeds back a timing adjustment value that is a detected value to the timing setting unit 102.

  FIG. 2 is a diagram for explaining channel fluctuation in a radio section between the radio transmission apparatus and the radio reception apparatus according to the present embodiment. In FIG. 2, the wireless transmission device 100 transmits modulated signals A and B from two transmission antennas ANT1 and ANT2, respectively, and the wireless reception device 150 receives modulated signals A and B by two reception antennas ANR1 and ANR2. The case where the synthesized signals are received and the signals are separated and demodulated is shown. Here, the modulation signals A and B in FIG. 2 correspond to the modulation signals 1 and 2 in FIG.

  In this case, it is necessary to demodulate each modulated signal by estimating four channel fluctuations h11 (t), h12 (t), h21 (t), and h22 (t) on the receiving side (t indicates time). Therefore, pilot symbols used for signal detection, timing detection, frequency offset estimation, transmission method information, propagation channel estimation, and the like need to be provided in modulated signals A and B as necessary.

  Incidentally, the symbols necessary for the demodulation described above can be collectively referred to as pilot symbols, unique words, preambles, etc., but in the present embodiment, these are all referred to as pilot symbols. Note that channel fluctuations h11 (t), h12 (t), h21 (t), and h22 (t) are estimated using pilot symbols.

  FIG. 3 is a block diagram showing a configuration of the wireless transmission apparatus according to the present embodiment. Note that the wireless transmission device 300 in FIG. 3 describes the wireless transmission device 100 in FIG. 1 in detail, and the frame configuration unit 101 in FIG. 1 includes the frame configuration units 301-1 and 301-2 in FIG. This corresponds to the modulators 302-1 and 302-2. Also, the timing setting unit 102 in FIG. 1 corresponds to the radio units 303-1 and 303-2 and the timing setting unit 304 in FIG.

  Frame configuration sections 301-1 and 301-2 respectively transmit digital data A and transmission digital data B to timing detection symbols used for detection of reception timing in radio reception device 150 and synchronous detection in radio reception device 150. Then, a pilot symbol used for channel estimation or the like is inserted to form a frame, and framed digital data is output to modulation sections 302-1 and 302-2.

  Modulation sections 302-1 and 302-2 perform modulation processing on the framed digital data, respectively, and output modulated signals to radio sections 303-1 and 303-2.

  The radio units 303-1 and 303-2 respectively convert the frequency of the modulated signal for radio transmission, and transmit the transmission signal from the transmission antennas ANT 1 and ANT 2 at the transmission timing set by the timing setting unit 304. Here, at the time of the first transmission, the timings of transmitting transmission signals from the transmission antennas ANT1 and ANT2 are the same, and the radio units 303-1 and 303-2 do not use the input from the timing setting unit 304.

  The timing setting unit 304 sets the transmission timing of the transmission signal based on the timing adjustment value indicating the shift in reception timing detected by the wireless reception device shown in FIG. Instruct the transmission timing.

  Radio section 352 converts the high-frequency signal transmitted from the radio reception apparatus shown in FIG. 4 and received by reception antenna 351 to a baseband signal, and outputs the baseband signal to demodulation section 353. Here, in general, the receiving antenna 351 and the transmitting antennas ANT1 and ANT2 are commonly used in terms of circuit scale, cost, etc., but other antennas may be used. The received signal can also be received from a plurality of antennas.

  Demodulation section 353 demodulates the baseband signal and outputs the timing adjustment value and the received digital data to frame separation section 354. The frame separation unit 354 separates the timing adjustment value and outputs it to the timing setting unit 304.

  FIG. 4 is a block diagram showing a configuration of the radio reception apparatus according to the present embodiment. Note that the wireless reception device 400 in FIG. 4 describes the wireless reception device 150 in FIG. 1 in detail, and the timing detection unit 151 in FIG. 1 corresponds to the timing detection unit 451 in FIG.

  Radio sections 401-1 and 401-2 convert high-frequency signals received by reception antennas ANR <b> 1 and ANR <b> 2 into baseband signals, and output the baseband signals to frame separation sections 402-1 and 402-2.

  Frame demultiplexing units 402-1 and 402-2 demultiplex pilot symbols and data symbols from the baseband signal, respectively, and output pilot symbols to channel estimation units 403-1 to 403-4, and data symbols are demodulating unit 404. And the timing detection symbol is output to the timing detection unit 451.

  Channel estimation sections 403-1 to 403-4 each perform channel estimation using pilot symbols and output a channel estimation value to demodulation section 404.

  Demodulating section 404 demodulates the data symbol using the channel estimation value and outputs received digital data A and B corresponding to transmitted digital data A and B.

  The timing detection unit 451 detects a reception timing shift using the timing detection symbol, and outputs a timing adjustment value, which is a detected value, to the frame configuration unit 452.

  Frame configuration section 452 receives timing adjustment values and transmission digital data as input, and configures frames including pilot symbols and data symbols in the same manner as frame configuration sections 301-1 and 301-2 in radio transmission apparatus 300. The digitized digital data is output to the modulation unit 453.

  Modulation section 453 performs modulation processing on the framed digital data and outputs a modulated signal to radio section 454.

  The radio unit 454 converts the frequency of the modulated signal for radio transmission, and transmits the transmission signal from the transmission antenna 455 to the radio transmission apparatus 300. Here, in general, the transmission antenna 455 and the reception antennas ANR1 and ANR2 are commonly used in terms of circuit scale, cost, etc., but other antennas may be used. Further, the transmission signal can be transmitted from a plurality of antennas.

  FIG. 5 is a diagram illustrating a frame configuration example of the modulation signal A and the modulation signal B transmitted from the wireless transmission device 300. FIG. 5 shows a frame configuration on the time axis as an example. In FIG. 5, symbols 501 and 552 are timing detection symbols for modulated signals A and B, symbols 502 and 551 are null symbols (symbols that do not transmit anything) of modulated signals A and B, and symbols 503, 553 is a pilot symbol for demodulating the data symbols of modulated signals A and B, and symbols 504 and 554 are data symbols of modulated signals A and B. In the present embodiment, in order to explain that the transmission timing is adjusted using the timing detection symbol, the timing detection symbol and the pilot symbol are described separately. Further, although a signal detection symbol may be arranged before the timing detection symbol 501 and the null symbol 551, it is omitted in this embodiment. Details of the configuration of each symbol will be described later.

  FIG. 6 is a diagram illustrating a frame configuration example of a modulation signal transmitted from the wireless reception device 400. In FIG. 6, a symbol 601 is a timing adjustment symbol, and includes a timing adjustment value output by the timing detection unit 451 of the wireless reception device 400. Symbol 602 is a pilot symbol and symbol 603 is a data symbol.

  FIG. 7 is a diagram for explaining transmission timing adjustment for aligning the reception timing in the reception antenna ANR1 according to the present embodiment. Based on the timing adjustment value ΔTr1 fed back from the wireless reception device 400, the transmission timing of the modulated signal B is transmitted earlier by ΔTr1. As a result, the signal 1 received by the receiving antenna ANR1 is a signal in which two transmission signals are accurately multiplexed.

  Next, a specific example of a transmission frame configuration for detecting transmission timing generated in the frame configuration unit in FIG. 1 will be described.

  FIG. 8 is a diagram illustrating a configuration example of the timing detection symbols 501 and 552 of the modulation signal A and the modulation signal B in FIG. FIG. 8 shows an example using orthogonal codes.

The modulated signal shown in FIG. 8 is a signal obtained by performing modulation called bi-phase modulation on an unmodulated pulse signal. Bi-phase modulation is expressed by the following equation (1) using an unmodulated (or reference) pulse signal p (t).
S ₁ = p (t), S ₂ = -p (t) (1)

The modulated signal A generates pulses S ₁ , S ₁ , S ₁ , S ₁ indicating ₁ , ₁ , ₁ , ₁ , respectively at times Tt0, Tt1, Tt2, and Tt3. The modulation signal B generates pulses S ₁ , S ₂ , S ₁ , S ₂ indicating 1, -1, 1, -1, respectively at times Tt4, Tt5, Tt6, and Tt7. Tt0, Tt1,..., Tt7 are equally spaced.

  FIG. 9 is a diagram illustrating a timing detection method based on orthogonal code correlation processing in a received signal received by the receiving antenna ANR1. In order to calculate the timing of the modulation signal A, the autocorrelation value is calculated by multiplying 1, 1, 1, 1 which is the same as the code used on the transmission side. By calculating the autocorrelation value after the modulated signal A transmitted at times Tt0, Tt1, Tt2, and Tt3 on the transmitting side arrives at the receiving antenna ANR1, an autocorrelation value is obtained at the time Tr1A on the receiving side. At this time, the autocorrelation value is calculated by multiplying the same code used on the transmission side by 1, -1, 1, -1, even when calculating the timing of the modulated signal B. However, the autocorrelation value calculation for the modulation signal B starts at the same time as the calculation for the modulation signal A. In FIG. 8, since the modulation signal A is transmitted before the modulation signal B, the autocorrelation value for the modulation signal A is obtained first. Note that this embodiment is not limited to this order, and the modulated signal B can be transmitted prior to or simultaneously with the modulated signal A.

  First, the autocorrelation value when the timing detection symbol 501 in FIG. 8 arrives at the receiving side will be described. The autocorrelation value for the modulation signal A is 1 × 1 + 1 × 1 + 1 × 1 + 1 × 1 = 4, and the autocorrelation value for the modulation signal B is 1 × 1 + 1 × (−1) + 1 × 1 + 1 × (−1) = 0. Become. Here, it is assumed that there are no error factors such as distortion of the modulation signal due to propagation channel fluctuation and noise in the circuit.

  Next, the autocorrelation value when the timing detection symbol 552 of FIG. 8 arrives at the receiving side will be described. By calculating the autocorrelation value after the modulated signal B transmitted at times Tt4, Tt5, Tt6, and Tt7 on the transmitting side arrives at the receiving antenna ANR1, an autocorrelation value is obtained at the time Tr1B on the receiving side. The autocorrelation value for modulated signal A is 1 × 1 + (− 1) × 1 + 1 × 1 + (− 1) × 1 = 0, and the autocorrelation value for modulated signal B is 1 × 1 + (− 1) × (−1. ) + 1 × 1 + (− 1) × (−1) = 4.

As described above, the timing adjustment value ΔTr1 can be obtained from the following equation (2) from the arrival time difference (Tr1B−Tr1A) obtained from the correlation processing and the transmission time difference (Tt4−Tt0) on the transmission side.
ΔTr1 = T12−T11 = (Tr1B−Tr1A) − (Tt4−Tt0)
... (2)

  By feeding back this ΔTr1 to the transmission side and adjusting the transmission timing, it is possible to obtain a reception signal that is MIMO-multiplexed with high accuracy on the reception side.

  In addition, by using the orthogonal code in this way, the arrival timing of the modulated signal can be obtained, and the antenna to which the obtained modulated signal is transmitted can be identified.

  The timing detection in the receiving antenna ANR1 described with reference to FIGS. 8 and 9 can be similarly realized for the other receiving antennas.

  Further, the minimum unit of the length of the data symbols 504, 554, and 603 shown in FIGS. 5 and 6 is zero. In other words, it is possible to adopt a configuration in which no data symbol is transmitted in the timing setting period. This enables efficient timing setting without transmitting invalid data symbols.

  FIG. 10 is a diagram for explaining transmission timing adjustment for aligning the reception timing in the reception antenna ANR2 according to the present embodiment. Based on the timing adjustment value ΔTr2 fed back from the wireless reception device 400, the transmission timing of the modulated signal B is transmitted earlier by ΔTr2. As a result, the reception signal 2 received by the reception antenna ANR2 can be a signal in which two transmission signals are accurately multiplexed.

  FIG. 11 is a diagram illustrating a timing detection method based on orthogonal code correlation processing in the reception antenna ANR2.

  When calculating the timing of the modulated signal A for the signal received by the receiving antenna ANR2, the autocorrelation value is calculated by multiplying the same code used on the transmitting side by 1, 1, 1, 1. To do. By calculating the autocorrelation value after the modulated signal A transmitted at times Tt0, Tt1, Tt2, and Tt3 on the transmitting side arrives at the receiving antenna ANR2, an autocorrelation value is obtained at the time Tr2A on the receiving side. At this time, also in the case of calculating the timing of the modulated signal B, the autocorrelation value is calculated by multiplying the same code used on the transmission side, 1, -1, 1, -1. However, the autocorrelation value calculation for the modulation signal B starts at the same time as the calculation for the modulation signal A. In FIG. 8, since the modulation signal A is transmitted before the modulation signal B, the autocorrelation value for the modulation signal A is obtained first.

  First, the autocorrelation value when the timing detection symbol 501 in FIG. 8 arrives at the receiving side will be described. The autocorrelation value for the modulation signal A is 1 × 1 + 1 × 1 + 1 × 1 + 1 × 1 = 4, and the autocorrelation value for the modulation signal B is 1 × 1 + 1 × (−1) + 1 × 1 + 1 × (−1) = 0. Become. Here, it is assumed that there are no error factors such as distortion of the modulation signal due to propagation channel fluctuation and noise inside the circuit.

  Next, the autocorrelation value when the timing detection symbol 552 of FIG. 8 arrives at the receiving side will be described. By calculating the autocorrelation value after the modulated signal B transmitted at times Tt4, Tt5, Tt6, and Tt7 on the transmitting side arrives at the receiving antenna ANR2, an autocorrelation value is obtained at the time Tr2B on the receiving side. . The autocorrelation value for modulated signal A is 1 × 1 + (− 1) × 1 + 1 × 1 + (− 1) × x1 = 0, and the autocorrelation value for modulated signal B is 1 × 1 + (− 1) × (−1. ) + 1 × 1 + (− 1) × (−1) = 4.

As described above, from the arrival time difference (Tr2B-Tr2A) obtained from the correlation processing and the transmission time difference (Tt4-Tt0) on the transmission side, the timing adjustment value ΔTr2 can be obtained by the following equation (3).
ΔTr2 = T22−T21 = (Tr2B−Tr2A) − (Tt4−Tt0)
... (3)

  By feeding back this Tr2 to the transmission side and adjusting the transmission timing, a reception signal multiplexed with high accuracy on the reception side can be obtained.

FIG. 12 is a diagram illustrating a method of adjusting reception timings at a plurality of reception antennas according to the present embodiment. For the timing adjustment values ΔTr1 and ΔTr2 obtained for the received signal 1 and the received signal 2, a function f (x, y) of the following equation (4) is defined.
f (ΔTr1, ΔTr2) (4)
However, f (x, y) is a value determined by the values of x and y.

On the transmission side, the transmission timing of the transmission antenna ANT2 is adjusted by f (ΔTr1, ΔTr2) (advance or delay with respect to the transmission antenna ANT1). FIG. 12 shows, as an example, the case where the above formula (4) is specifically the following formula (5).
f (ΔTr1, ΔTr2) = (ΔTr1 + ΔTr2) / 2 = ΔTr_ave
... (5)

  In general, when the distance between the transmitting and receiving antennas (for example, the transmitting antenna ANT1 and the receiving antenna ANR1) is longer than the distance between the transmitting antennas ANT1 and ANT2 and the distance between the receiving antennas ANR1 and ANR2, the difference between ΔTr1 and ΔTr2 Therefore, ΔTr_ave <ΔTr1, ΔTr_ave <ΔTr2, and by adjusting the transmission timing by ΔTr_ave, it is possible to realize multiplexing with higher accuracy than before adjustment. In short, it is important to adjust the transmission timing using ΔTr1 and ΔTr2 so that more accurate multiplexing can be realized on the reception side as compared to before the transmission timing adjustment. Note that a case where a part of all the antennas included in the transmission device or the reception device is not used will be described in Embodiment 2.

  Here, in the above description, the timing of the transmission antenna ANT2 is adjusted with reference to the transmission antenna ANT1, but the antenna to be adjusted may be configured to adjust the transmission timing of the transmission antenna ANT1 with reference to the transmission antenna ANT2. Similar effects can be obtained. The same effect can be obtained by adjusting the transmission timings of both the transmission antennas ANT1 and ANT2.

  FIG. 13 is a diagram illustrating another configuration example of the timing detection symbol of the modulation signal in FIG. The modulation signal shown in FIG. 13 is a configuration example when the timing detection symbols 501 and 552 are narrower than the other pulse widths 503, 504, 553, and 554.

  In general, the transmission timing can be detected more accurately as the pulse width is narrower. Therefore, the transmission timing can be adjusted more accurately, and more accurate MIMO multiplexing on the receiving side can be realized.

  Here, as the timing detection symbols 501 and 552, (a) the narrowest pulse signal that can be generated as a device by the wireless transmission device 300, (b) the narrowest pulse signal in the wireless standards to which the wireless transmission device 300 conforms, ( c) Signals having different pulse widths including the pulse signals (a) and (b) above can be used. Here, since (a) and (b) have already been described, an example of (c) will be described below.

  As signals having different pulse widths, (c-1) signals having the same pulse width as portions other than timing detection symbols (for example, data portions 504 and 554), and (c-2) portions other than timing detection symbols (for example, data portions) Consider a signal having a pulse width narrower than (504) and (554) and wider than (a) or (b), and (c-3) a signal of (a) or (b).

  (C-1) is used at the start of transmission. This has an advantage that a load due to a change in pulse width in the wireless transmission device is not applied by using a signal having the same pulse width as that of a portion other than the timing detection symbol. When the transmission timing adjustment value detected on the receiving side by the pulse signal of (c-1) is sufficient to realize MIMO multiplexing, switching to (c-2) is not performed, and (c-1 ) Only completes the timing adjustment. When sufficient timing adjustment cannot be performed only by (c-1), the timing adjustment value is obtained using the signal (c-2). Hereinafter, as in the case of (c-1), when the transmission timing adjustment value detected on the reception side by the pulse signal of (c-2) is sufficient to realize MIMO multiplexing (c− Switching to 3) is not performed, and the timing adjustment is completed in (c-2). If sufficient timing adjustment cannot be performed using (c-2), the timing adjustment value is obtained using the signal (c-3). As described above, by making the pulse width used for the timing detection symbol variable, unnecessary pulse width change can be avoided, and at the same time, timing adjustment can be performed with higher accuracy.

  At this time, it is possible to determine whether the timing adjustment is sufficient on either the transmission side or the reception side. When implemented on the receiving side, the determination result is fed back in addition to ΔTr1 and ΔTr2 or instead of ΔTr1 and ΔTr2.

  FIG. 14 is a diagram illustrating another configuration example of the timing detection symbol of the modulation signal in FIG. In FIG. 14, the Bi-phase phase is 0 [rad] for the timing detection symbol 501 (used as 1 in the correlation processing) and π [for the timing detection symbol 552 without applying orthogonal codes as shown in FIG. rad] (used as -1 in the correlation process). On the receiving side, by performing correlation processing based on this phase value, it is possible to determine the arrival timing of the modulated signal with a simple configuration and processing compared to the case where orthogonal codes are used. Can identify the antenna from which it was transmitted.

  FIG. 15 is a diagram illustrating another configuration example of the timing detection symbol of the modulation signal in FIG. In FIG. 15, Pulse Position Modulation (PPM) is used as the modulation method. In this modulation method, modulation is performed at a pulse position (a position here is a position on the time axis) within a pulse period (for example, Tt1-Tt0). In FIG. 15, when the transmission digital signal is 1 (used as 1 in the correlation process), transmission is performed at the head position of the pulse period, and when the transmission digital signal is 0 (used as -1 in the correlation process), the pulse period A pulse is transmitted at a position delayed by T_PPM from the head position. Since PPM can realize modulation with a single pulse width and pulse shape, it can be a simple transmission signal.

  FIG. 16 is a diagram illustrating another configuration example of the timing detection symbol of the modulation signal in FIG. In FIG. 16, OOK is used as the modulation method. This modulation method generates a pulse when the transmission digital signal is 1 (used as 1 in correlation processing), and does not generate a pulse when the transmission digital signal is 0 (used as 0 in correlation processing). OOK can realize modulation with a single pulse width and pulse shape. Further, since the pulse signal is not generated when the transmission digital signal is 0, transmission can be performed with low power consumption.

  FIG. 17 is a diagram illustrating another configuration example of the timing detection symbol of the modulation signal in FIG. In FIG. 17, Orthogonal Pulse Modulation (OPM) is used as the modulation method. This modulation method generates a pulse signal having a quadrature relationship as a function when the transmission digital signal is 1 or 0. OPM is a modulation method suitable for multiple access.

  FIG. 18 is a diagram illustrating another configuration example of the timing detection symbol of the modulation signal in FIG. In FIG. 18, Pulse Wide Modulation (PWM) is used as the modulation signal. Therefore, “1” is obtained when the pulse width is narrow, and “−1” is obtained when the pulse width is wide. PWM is known as a control method for stabilizing the output voltage of the switching power supply, and the output voltage can be controlled by changing the ratio of the ON time and OFF time of the switching transistor. For example, a constant voltage can always be maintained by increasing the ON time when the output voltage decreases and decreasing it when it increases.

  As described above, according to the present embodiment, in a method in which modulated signals are transmitted simultaneously from a plurality of antennas, the transmission timing is adjusted based on the transmission timing adjustment value detected on the receiving side, so that more accurate multiplex communication is possible. Can be realized.

  In the above-described embodiment, the case where the configuration of the timing detection symbol is as shown in FIGS. 8, 13, 14, 15, 16, 17, and 18, is described. The configuration of the symbols for use is not limited to this. For example, a configuration may be adopted in which symbols obtained by cyclically shifting timing detection symbols on the time axis (cyclic delay) are output from other antennas.

  In the above description, the case where the transmission timing is changed by the radio units 303-1 and 303-2 based on the timing setting value set by the timing setting unit 304 has been described. However, the present invention is not limited to this, and the modulation is performed. The transmission timing may be changed by the units 302-1 and 302-2. FIG. 19 is a block diagram showing the configuration of the wireless transmission device in this case. The wireless transmission device 1900 of FIG. 19 has a timing setting value set by the timing setting unit 304 as compared with the wireless transmission device 300 of FIG. The difference is that the signals are input to the modulators 302-1 and 302-2. In the case of adaptive transmission timing adjustment in which the pulse width is adaptively changed as described with reference to FIG. 13, the configuration is as shown in FIG.

  In the above description, the timing adjustment value is calculated on the reception side. However, the present invention is not limited to this, and the timing adjustment value may be calculated on the transmission side. For example, only the calculation of ΔTr1 and ΔTr2 is performed on the reception side, and feedback is performed to the transmission side. On the transmission side, the timing setting unit 102 determines the transmission timing setting value using ΔTr1 and ΔTr2. An example of this is Tr_ave described with reference to FIG. In this case, the load on the receiving side is reduced. Thus, in the present invention, it is only necessary to set the transmission timing based on the reception timing error in each reception antenna.

  In the above description, a case has been described in which a transmission timing can be changed in ANT1 and ANT2 in a wireless transmission device provided with two transmission antennas ANT1 and ANT2. However, the present invention is not limited to this, and transmission is possible. The present invention can be widely applied to an apparatus that transmits m modulation signals with m antennas. In addition, the number of transmission antennas and the number of modulated signals to be transmitted do not need to match, the number of transmission antennas is made larger than the number of transmission modulated signals, a transmission antenna is selected, and a modulation signal is transmitted from the selected transmission antenna. Also good. Details of this content will be described in the second embodiment. Moreover, the antenna may form one antenna part with a plurality of antennas.

  In the above description, a radio transmission apparatus that modulates and transmits a pulse signal has been described as an example. However, the present invention is not limited to this, and OFDM modulation may be used. In this case, the spreading section in the radio transmitting apparatus in FIG. 20 and the radio receiving apparatus in FIG. 21 is replaced with an IFFT (Inverse Fast Fourier Transform) section, and the despreading section is replaced with an FFT section. In general, when OFDM modulation is used, a configuration is adopted in which the influence of intersymbol interference due to delayed waves is removed by inserting a guard interval. In this case as well, the symbol time length and the arrival of transmission signals from multiple antennas are adopted. By adjusting the transmission timing based on the relationship with the time difference, it is possible to realize MIMO multiplexing with higher accuracy (small intersymbol interference).

  The present invention can also use a spread spectrum communication system. In the UWB transmission system, a case where one pulse signal is regarded as one chip of a spread spectrum communication system and is replaced with a signal of one symbol by a plurality of pulses is referred to as spread spectrum communication. 20 is a block diagram showing a configuration of the wireless transmission device in this case. The wireless transmission device 2000 of FIG. 20 is different from the wireless transmission device 300 of FIG. The diffusion unit 2002 is added. FIG. 21 is a block diagram showing the configuration of the wireless reception device in this case. The wireless reception device 2100 in FIG. 21 is different from the wireless reception device 400 in FIG. The diffusion unit 2102 is added. Spreading units 2001-1 and 2001-2 replace the 1-symbol signals output from modulation units 302-1 and 302-2 with a plurality of pulse signals, respectively, and arrange these pulse signals in the time axis direction. The despreading units 2101-1 and 2101-2 take out a 1-bit symbol by adding a plurality of pulse signals.

  Further, the present invention can obtain the same effect even when space-time coding, space-time block code, and space-time trellis code are applied. In spatio-temporal coding, spatio-temporal block code, and spatio-temporal trellis code, the principle is good even when the number of receiving antennas n is m> = n with respect to the number of transmitting antennas m (m> = 2). A large reception quality (theoretically maximum gain) can be obtained, and the effect of the combination with the method of this embodiment is great.

(Embodiment 2)
In Embodiment 2, an antenna selection method when a plurality of transmission / reception antennas are used in the method described in Embodiment 1 will be described.

  FIG. 22 is a block diagram showing a configuration of radio transmitting apparatus 2200 according to the present embodiment. Portions that operate in the same manner as in FIG. 3 are assigned the same numbers, and descriptions thereof are omitted.

  Frame configuration sections 2201-1 and 2201-2 respectively transmit digital data C and transmission digital data D to timing detection symbols used for detection of reception timing in radio reception apparatus 2300, and synchronous detection in radio reception apparatus 2300. A pilot symbol used for channel estimation or the like is inserted to form a frame, and framed digital data is output to modulators 2202-1 and 202-2.

  Modulation sections 2202-1 and 202-2 perform modulation processing on the framed digital data, respectively, and output the modulated signals to radio sections 2203-1 and 2203-2.

  The radio units 2203-1 and 2203-2 respectively convert the frequency of the modulated signal for radio transmission, and transmit the transmission signal from the transmission antennas ANT3 and ANT4 at the transmission timing set by the timing setting unit 304. Here, at the time of the first transmission, the transmission signals are transmitted from the transmission antennas ANT1, ANT2, ANT3, and ANT4 at the same time, and the radio units 303-1, 303-2, 2203-1, and 203203-2 are timing setting units. The input from 304 is not used.

  FIG. 23 is a block diagram illustrating a configuration of radio receiving apparatus 2300 according to the present embodiment. Portions that operate in the same manner as in FIG. 4 are assigned the same reference numerals, and descriptions thereof are omitted.

  Radio sections 2301-1 and 2301-2 convert high-frequency signals received by reception antennas ANR3 and ANR4 to baseband signals, and output the baseband signals to frame separation sections 2302-1 and 2302-2.

  Frame demultiplexing sections 2302-1 and 2302-2 demultiplex pilot symbols and data symbols from the baseband signals, respectively, and output pilot symbols to channel estimation sections 2303-1 to 2303-4, and demodulating section 404 with data symbols. And the timing detection symbol is output to the timing detection unit 451.

  Channel estimation sections 2303-1 to 2303-4 each perform channel estimation using pilot symbols and output channel estimation values to demodulation section 404.

  FIG. 24 is a diagram illustrating a frame configuration example of the modulation signal A to the modulation signal D transmitted from the wireless transmission device 2200, and description of portions that operate in the same manner as in FIG. 5 is omitted. FIG. 24 shows a frame configuration on the time axis as an example. Symbols 2401 and 2451 are null symbols of modulated signals C and D, respectively. Symbols 2402 and 2452 are data symbols of modulated signals C and D, respectively. Symbols 2403 and 2453 are pilot symbols of modulated signals C and D, respectively. Symbols 2404 and 2454 are data symbols of modulated signals C and D, respectively. Also in the present embodiment, signal detection symbols are omitted as in the first embodiment.

  FIG. 25 is a diagram illustrating four cases, Case 1 to Case 4, as examples of reception signals in the reception antennas ANR1 to ANR4 when the frame illustrated in FIG. 24 is transmitted. Here, ANR1 is used as the case where Case1 occurs, but Case1 may also occur in some or all of the other antennas ANR2 to ANR4. The same applies to Case 2 to Case 4.

Case1 (ANR1)
Modulation signals A to D are received without overlapping on the time axis. In this case, the timing setting unit 304 of the wireless transmission apparatus 2200 adjusts the transmission timing using the method described in Embodiment 1 to multiplex (4 multiplex) all of the modulation signals A to D. It becomes possible.

Case2 (ANR2)
Modulated signal A and modulated signal B are received overlapping on the time axis. In this case, the timing setting unit 304 of the wireless transmission device 2200 (1) adjusts the transmission timing of one or both of the modulation signal A and the modulation signal B, and (2) one of the modulation signal A and the modulation signal B. The transmission is stopped and either one of the modulation signal C and the modulation signal D is multiplexed is selected.

Case 3 (ANR3)
Modulation signal A to modulation signal D are all received on the time axis. When two or more receiving antennas are received as in Case 3, it is possible to multiplex up to four. However, when Case 1 occurs at the same time as Case 3, it is very difficult to adjust the transmission timing, and the reception quality of multiplexed signals generally deteriorates. In this case, radio transmitting apparatus 2200 does not perform multiplexing itself.

Case4 (ANR4)
Although the modulation signal C is not received, the other modulation signals A, B, and D are received without overlapping on the time axis, and the timing setting unit 304 of the wireless transmission device 2200 transmits these three modulation signals. By adjusting the timing, a maximum of 3 multiplex communications is possible.

  As shown above, based on the observation results on the receiving side (reception timing on the time axis / frequency axis, correlation of waveforms, etc.), the antenna used for multiplex transmission is appropriately selected from all the antennas provided for each transmission / reception. By selecting, it is possible to perform multiplex communication in consideration of reception efficiency, reception quality, and the like.

  Note that the method of feeding back the result selected in FIG. 25 to the wireless transmission device has been described in Embodiment 1 with reference to FIG.

  26 is a diagram illustrating a frame configuration example of the modulated signal A to the modulated signal D transmitted from the wireless transmission device 2200 different from that in FIG. 24, and description of portions that operate in the same manner as in FIG. 5 is omitted.

  In FIG. 26, the null symbol is not arranged. In this case, the reception timing deviation is measured and the transmission timing is adjusted by using the orthogonal pulse described in Embodiment 1 with reference to FIG. The advantage of FIG. 26 over FIG. 24 is that the time required for measuring the reception timing deviation can be shortened.

  FIG. 27 is a diagram showing another example of the antenna selection method described in FIG. 25. Here, the case of the transmission antenna 3 and the reception antenna 2 will be described, but the number of each is not limited to this. .

In the received signal at ANR1, the arrival time difference between modulation signal A and modulation signal B is ΔT1-AB, the arrival time difference between modulation signal B and modulation signal C is ΔT1-BC, and the arrival time difference between modulation signal A and modulation signal C is ΔT1-AC. And Here, in consideration of the symbol time Ts_short of the modulation signal A to the modulation signal C itself and the transmission timing difference, the smallest difference among the three timing differences of the following equations (6) to (8) may be selected. . The reception signal in ANR2 may be implemented in the same manner as in ANR1.
(ΔT1-AB)-(Ts_short) (6)
(ΔT1-BC) − (Ts_short) (7)
(ΔT1-AC) − (Ts_short) − (Ts_short) (8)

  Here, when the selection results differ between ANR1 and ANR2, the antenna can be finally determined by using a method of selecting a smaller time difference or averaging. The important point is to reduce the arrival time difference of a plurality of symbols on the receiving side and realize highly accurate MIMO multiplex communication.

  Up to this point, it has been described that the reception timing is adjusted by changing the transmission timing based on the delay time measured on the reception side to realize highly accurate MIMO multiplex communication. However, by changing the transmission timing, It is also possible to switch to a transmission method that obtains a larger transmission diversity effect. For example, by transmitting the same pulse signal from two transmission antennas, the reception side can synthesize signals passing through different transmission paths, improve reception quality, and improve throughput. In addition, even when the signal from one antenna of the two signals is instantaneously interrupted, the reception quality necessary for data demodulation can be secured using the signal from the other antenna. .

  Note that the method described in this embodiment mode can be implemented in combination with another embodiment mode, for example, the frame structure described in Embodiment Mode 3.

(Embodiment 3)
In the third embodiment, a frame configuration used for transmission timing adjustment from a plurality of antennas described in the first and second embodiments will be described in detail.

  FIG. 28 is a diagram showing a frame configuration example described in contrast to the frame configuration in FIG. 5, and a portion indicated by a dotted line is a portion to be compared.

  The feature of FIG. 28 is the insertion of inter-antenna time difference estimation symbols 2802, 2852 and guard symbols 2803, 2805, 2853, 2855 to avoid inter-symbol interference. As a result, even when the reception timing deviation of transmission signals from a plurality of transmission antennas is large, it is possible to estimate the time difference between antennas with high accuracy and to perform multiplex transmission based on the estimation result due to the presence of guard symbols.

  FIG. 28 shows signal synchronization symbols 2801 and 2851, inter-antenna time difference estimation symbols 2802 and 2852, guard symbols 2803 and 2853, channel estimation symbols 2804 and 2854, guard symbols 2805 and 2855, communication information symbols 2806 and 2856, and data. It consists of symbols 2807 and 2857.

  Signal synchronization symbols 2801 and 2851 are symbols for synchronizing signals.

  Inter-antenna time difference estimations 2802 and 2852 are symbols for estimating the arrival time difference between antennas of a plurality of pulse signals (modulated signal A and modulated signal B). For example, autocorrelation as described in the first embodiment. A sequence having excellent cross-correlation characteristics is used.

  The guard symbols 2803 and 2853 are symbols inserted so that the inter-antenna time difference estimations 2802 and 2852 and the channel estimation symbols 2804 and 2854 do not cause intersymbol interference. For example, null symbols are used.

  The channel estimation symbols 2804 and 2854 are symbols necessary for performing equalization processing on the receiving side, synthesis processing based on amplitude / phase information, and the like.

  The guard symbols 2805 and 2855 are symbols inserted so that the channel estimation symbols 2804 and 2854 and the communication information symbols 2806 and 2856 do not cause intersymbol interference. For example, null symbols are used.

  The communication information symbols 2806 and 2856 include transmission method information (for example, the type of error correction code such as a convolutional code, a turbo code, an LDPC (Low Density Parity Check) code, the number of transmission multiplexed streams, etc.), and reception method information (for example, , Recommended smoothing (smoothing) method, detection method, etc.).

  Data symbols 2807 and 2857 are data bodies transmitted by the modulated signal A and the modulated signal B, and are data transmitted from a layer higher than a normal physical layer such as a MAC (Media Access Control) layer.

  In a system that does not need to perform channel estimation, the frame configuration is such that channel estimation symbols 2804 and 2854 and guard symbols 2805 and 2855 are deleted.

  In FIG. 28, symbols that are generally referred to as FCS (Frame Check Sequence) and that detect the frame errors of the modulated signal A and the modulated signal B are omitted.

  As described above, it is possible to estimate the time difference between antennas with high accuracy by appropriately inserting guard symbols in the transmission frame configuration.

  INDUSTRIAL APPLICABILITY The present invention is suitable for application to a radio communication system that requires high accuracy in the reception timing of a received signal in a system that transmits a modulated signal using a plurality of antennas.

Basic configuration diagram of radio transmitting apparatus and radio receiving apparatus according to Embodiment 1 of the present invention The figure explaining the channel fluctuation | variation of the radio area between the radio | wireless transmitter which concerns on the said embodiment, and a radio | wireless receiver. The block diagram which shows the structure of the radio | wireless transmitter which concerns on the said embodiment. The block diagram which shows the structure of the radio | wireless receiver which concerns on the said embodiment. The figure which shows the frame structural example of the modulation signal transmitted from the radio | wireless transmitter which concerns on the said embodiment. The figure which shows the frame structural example of the modulation signal transmitted from the radio | wireless receiver which concerns on the said embodiment. The figure explaining the transmission timing adjustment for aligning the reception timing in receiving antenna ANR1 of the said embodiment The figure which shows the structural example of the symbol for a timing detection of the modulation signal of FIG. The figure which shows the timing detection method based on the correlation process of an orthogonal code in receiving antenna ANR1 The figure explaining the transmission timing adjustment for aligning the reception timing in receiving antenna ANR2 of the said embodiment The figure which shows the timing detection method based on the correlation process of an orthogonal code in receiving antenna ANR2 The figure which shows the method to adjust the reception timing in the some receiving antenna which concerns on the said embodiment The figure which shows the other structural example of the symbol for a timing detection of the modulation signal of FIG. The figure which shows the other structural example of the symbol for a timing detection of the modulation signal of FIG. The figure which shows the other structural example of the symbol for a timing detection of the modulation signal of FIG. The figure which shows the other structural example of the symbol for a timing detection of the modulation signal of FIG. The figure which shows the other structural example of the symbol for a timing detection of the modulation signal of FIG. The figure which shows the other structural example of the symbol for a timing detection of the modulation signal of FIG. The block diagram which shows the other structure of the radio | wireless transmitter which concerns on the said embodiment. The block diagram which shows the other structure of the radio | wireless transmitter which concerns on the said embodiment. The block diagram which shows the other structure of the radio | wireless receiver which concerns on the said embodiment. The block diagram which shows the structure of the radio | wireless transmitter which concerns on Embodiment 2 of this invention. The block diagram which shows the structure of the radio | wireless receiver which concerns on the said embodiment. The figure which shows the frame structural example of the modulation signal transmitted from the radio | wireless transmitter which concerns on the said embodiment. The figure which shows the example of the received signal in the receiving antenna at the time of transmitting the flame | frame shown in FIG. The figure which shows the frame structural example of the modulation signal transmitted from the radio | wireless transmitter which concerns on the said embodiment. The figure which shows another example of the antenna selection method demonstrated in FIG. The figure which shows the example of a frame structure described in contrast with the frame structure of FIG. The figure explaining UWB transmission system The figure explaining a MIMO transmission system A diagram explaining a conventional problem

Explanation of symbols

100, 300, 1900, 2000, 2200 Wireless transmission device 101 Frame configuration unit 102 Timing setting unit 150, 400, 2100, 2300 Wireless reception device 151 Timing detection unit 301-1, 301-2, 2201-1, 201-2 frame Configuration unit 302-1, 302-2, 2202-1, 202-2 Modulation unit 303-1, 303-2, 2203-1, 2203-2 Radio unit 304 Timing setting unit 401-1, 401-2, 2301- 1, 2301-2 Radio unit 402-1, 402-2, 2302-1, 2302-2 Frame separation unit 403-1, 403-2, 403-3, 403-4, 2303-1, 2302-2, 2303 -3, 2303-4 Channel estimation unit 404 Demodulation unit 451 Timing detection unit

Claims (1)

A wireless transmission device used in UWB wireless communication,
A first antenna;
A second antenna;
Constitute a first frame by inserting the row of the first pulse signal is a first timing detection symbol data to be transmitted from the first antenna,
The columns of the second pulse signal is a second timing detection symbol constitute the insert City second frame data transmitted from the second antenna,
Frame forming means for configuring the pulse widths of the individual pulses of the first and second pulse signal trains to be shorter than the pulse widths of the other symbols ;
Transmitting means for transmitting the first frame from the first antenna, and transmitting the second frame from the second antenna with a predetermined time interval from the transmission time of the first frame ;
Receiving information about the deviation of reception timing communication partner apparatus is detected using a second symbol detection timing and the first timing detection symbol, the communication partner device is detected on the basis of the information Updating means for updating the predetermined time interval so as to reduce the deviation ;
A wireless transmission device provided.

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