JP2006013994A - Receiver, and communication apparatus using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a receiver capable of shortening a period of time for synchronization capture at the time of transmitting and receiving a signal by using a pulse string spread by a spreading code, and to provide a communication apparatus using the receiver. <P>SOLUTION: This synchronization detection type receiver receives a pulse signal spread by the spreading code as a received signal. The receiver is provided with a sequential searching part 0120 for searching a pulse position of the received signal by sequential searching, a code correlating part 0130 for calculating a cross-correlation value between a search result output outputted in each pulse cycle of a pulse signal and the diffusion code and outputting a cross-correlation value, and a signal detection/synchronization control part 0140 for detecting the peak of the cross-correlation value, determining the existence of the received signal and controlling the next search position of a pulse position in the sequential searching part on the basis of the determination result. The existence of the received signal is determined to establish synchronization capture. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a communication system that uses a pulse train spread by a spreading code as a transmission signal, and more particularly to a reception device including a synchronization acquisition device for the transmission signal and a communication device using the same.

  In recent years, wireless terminal devices such as mobile phones and wireless local area networks (LANs) have remarkably spread, and the frequency band used has reached the GHz band. For this reason, it is difficult to find a new frequency band. Under such circumstances, a communication method using an impulse-like pulse train having an extremely narrow pulse width (for example, around 1 ns) has been attracting attention as a new method of using frequency resources. As a communication method using such a pulse train, for example, there is an ultra wide band impulse radio (hereinafter abbreviated as “UWB-IR”) communication method. As an example, Non-Patent Document 1 discloses a UWB-IR communication system that modulates a Gaussian monopulse by a PPM (Pulse Position Modulation) method.

  In communication systems using these pulse trains, information transmission is performed by intermittent transmission and reception of energy signals, unlike signal transmission using normal continuous waves.

  Since the pulses constituting the pulse train have a very narrow pulse width as described above, the signal spectrum has a wider frequency band than that of communication using a normal continuous wave, and the signal energy is dispersed. As a result, the signal energy per unit frequency band is very small. Therefore, communication is possible without causing interference with other communication systems, and frequency bands can be shared.

  An example of signal waveforms in the UWB-IR communication system is shown in FIG. FIG. 37A shows an example of a UWB signal waveform obtained by modulating a pulse train by Binary Phase Shift Keying (BPSK) modulation, and the polarity of the pulse train is inverted according to the transmission data value “1” or “0”. FIG. 37B shows an example of a UWB-IR signal waveform obtained by modulating a pulse train by PPM modulation. In PPM modulation, the temporal position of a pulse is shifted according to the value “1” or “0” of transmission data. An example of a PPM modulation type UWB communication apparatus is disclosed in Patent Document 2.

  Next, in the UWB-IR communication system, in general, direct spreading in which a pulse train is spread by a spreading code is employed. In this case, a plurality of spread pulses correspond to one data value. Examples of the direct diffusion type UWB-IR communication device are disclosed in Patent Document 1 and Patent Document 6.

  In a communication method using direct spreading, synchronization acquisition is performed in synchronization by receiving a spread signal of an incoming signal and a spread code generated by a receiving apparatus (see, for example, Patent Document 3 and Patent Document 4). In particular, Patent Document 5 discloses an example in which correlation for synchronization acquisition is performed using delayed detection.

JP 2002-335189 A Japanese National Patent Publication No. 10-508725 Japanese translation of PCT publication No. 2003-529257 International Publication No. WO0193444 Pamphlet JP 2003-169000 A JP 2002-335228 A Moe Z. Win et al., “Impulse Radio: How It Works”, US literature, IEEE Communications Letters 2nd Volume 2, page 36-38 (February 1998)

  In UWB-IR communication, interference with other communication systems can be further reduced by using direct spreading, but there is a problem in that it takes a long time to acquire synchronization. In the following, the problem of synchronization acquisition will be described for the BPSK modulation type UWB-IR communication system using direct spreading.

  FIG. 38 is a block diagram showing a schematic configuration of a BPSK modulation type UWB-IR transmission apparatus using direct spreading. The transmitter includes an information source (DATA) 3510, a spread code generator (CODEG) 3520, a multiplier (MLT) 3530, a pulse generator (PLSG) 3540, a high frequency (hereinafter abbreviated as “RF”) front end (RFFE) 3550, including antenna 0000.

  The information source 3510 outputs transmission data to be transmitted. Spreading code generation section 3520 outputs a spreading code sequence such as a PN (Pseudo-random Noise) sequence. At this time, the spreading code sequence is generated at a rate higher than the rate at which the information source 3510 generates transmission data. The transmission data output from the information source 3510 by the multiplier 3530 is multiplied by the spreading code sequence generated by the spreading code sequence generating unit 3520 and directly spread to generate a spread data sequence.

  The pulse generation unit 3540 generates a transmission pulse train according to the spread data sequence that is the output of the multiplication unit 3530. At this time, the polarity of the pulse constituting the output pulse train is inverted according to the value of the spread data train. The pulse train generated by the pulse generator 3540 is converted into a transmission signal by being subjected to RF signal processing such as amplification and band limitation by the RF front end 3550, and transmitted from the antenna 0000.

  FIG. 39 is a block diagram showing a schematic configuration of a BPSK modulation type UWB-IR receiving apparatus using direct spreading. The receiver is an antenna 0000, an RF front end unit (RFFE) 3610, a correlation unit (CORR) 3620, a pulse addition unit (PLSADD) 3630, a signal detection / synchronization control unit (FIND / SYNCCTL) 3640, a timing signal generation unit (TMSIGG) 3650, a template waveform sequence generation unit (TEMPTRNG) 3660, a spread code generation unit (CODEG) 3661, a pulse generation unit (PLSG) 3661, and a detection unit (DETET) 3670.

  The RF front end 3610 performs signal processing such as amplification, noise removal, and frequency conversion on the signal received by the antenna 0000 as necessary, and outputs a reception signal S3610. The correlation unit 3620 multiplies and integrates the template waveform sequence S3660 generated in the template waveform sequence generation unit 3660 and the received signal S3610 from the RF front end 3610, and further integrates one information unit section (bit) in the pulse addition unit 3630. To output a correlation signal S3630. The correlation signal is subjected to data discrimination by the detection unit 3670 and decoded.

  Spreading code generating section 3661 generates the same spreading code sequence as that used for direct spreading on the transmission side in synchronization with the reference clock output from timing signal generating section 3650. Template waveform sequence generation section 3660 generates template waveform sequence S3660 in synchronization with the spreading code sequence generated by spreading code generation section 3661. At this time, the polarity of the pulse is inverted according to each code of the spread code sequence. The spread spectrum code generation unit 3661 and the pulse generation unit 3362 constitute a template waveform sequence generation unit 3660, and the generated pulse sequence is referred to as a template waveform sequence.

  Since the phase of the spread code sequence in the received modulated pulse train is unknown in the initial state of starting reception, the signal detection / synchronization control unit 3640 generates a spread code so that the average energy of the correlation signal S3630 is maximized. The phase of the spread code sequence output from unit 3661 is shifted. In the phase where the average energy of correlation signal S3630 is maximum, the received signal and the phase of the spread code sequence generated by the receiving apparatus, and the pulse position of the received signal and the pulse position of the template waveform sequence match. Further, the synchronization is established by finely adjusting the frequency of the reference clock generated from the timing signal generation unit 3650 so that the average energy of the correlation signal is maximized.

  After the synchronization is established by such a procedure, the signal detection / synchronization control unit 3640 continues the frequency or the reference clock generated from the timing signal generation unit 3650 so that the average energy of the correlation signal S3630 becomes maximum. Change phase and maintain synchronization.

  The procedure of the conventional typical sequential search method in the signal acquisition in the initial state of starting reception as described above will be described with reference to FIG. FIG. 40 shows the reception signal S3610, template waveform sequence S3660, and correlation signal S3630 in FIG. However, for the sake of explanation, one information unit (1 bit) is expressed by 4 pulses {1, -1, 1, 1}. In a typical communication system, one information unit is usually expressed by several hundred pulses.

  As shown in FIG. 40, the timing is searched so that the correlation signal energy is maximized while shifting the template waveform sequence. However, in a general synchronization establishment state, it is necessary to match the phase of the spread code sequence on the transmission side and the reception side, and both the pulse position of the received signal and the pulse position of the template waveform sequence. In the conventional method, There is a problem that increases the signal acquisition time.

  As an example, when considering data transmission at a rate of 250 kbps in a pulse sequence having a pulse width of 2 nanoseconds, the shift amount of one template waveform sequence is generally about 1/4 of the pulse width, In this example, it is 0.5 nanoseconds. Since one information unit section (Ts) (spread code sequence length) is 4 microseconds, the maximum number of searches (timing shift times) until the correlation signal becomes maximum is 4 microseconds / 0.5 nanometers. 8000 times in a second. Converting this to time results in a time of 32 milliseconds. As a result, in applications such as packet communication, a significant reduction in efficiency is inevitable.

  When the modulated pulse waveform shown in the upper part of FIG. 41 in which the carrier wave is modulated by the pulse waveform is transmitted, a local signal having the same frequency as the carrier wave is generated on the receiving device side, multiplied by the received signal, and the high frequency component is obtained. By removing, the original pulse waveform is extracted. At this time, if there is a deviation between the frequency of the carrier wave and the frequency of the local signal, the amplitude of the pulse waveform after conversion fluctuates and the correlation signal deteriorates, so frequency synchronization is required, resulting in an increase in synchronization acquisition time. To do. 41 is a conceptual diagram of a pulse waveform after conversion when there is no deviation between the frequency of the carrier wave and the local signal in the middle stage of FIG. 41 and a pulse waveform after conversion when there is a deviation between the frequency of the carrier wave and the local signal at the lower stage of FIG. Indicates.

  An object of the present invention is to provide a receiving apparatus and a communication apparatus using the same, which can shorten the time for acquisition of synchronization when a signal is transmitted and received using a pulse train spread by a spreading code.

  In order to achieve the above object, a receiving apparatus of the present invention is a synchronous detection type receiving apparatus that receives a pulse signal spread by a spreading code as a received signal, and searches for the pulse position of the received signal by a sequential search. A sequential search unit, a code correlation unit for obtaining a cross-correlation between the search result output output for each pulse period of the pulse signal and the spreading code, and outputting the cross-correlation value, and a peak of the cross-correlation value And a signal detection / synchronization control unit for controlling the next search position of the pulse position in the sequential search unit based on the determination result.

  With the above configuration, the pulse position search is performed for pulse synchronization, and the correlation of the spreading code is obtained each time the pulse position search is performed. Therefore, the search time by the sequential search is shortened, and the pulse over the entire length of one information unit is obtained. The synchronization acquisition time can be shortened as compared with the conventional case where the position search is performed.

  When receiving a modulated pulse waveform, a pulse signal based on a spread code is obtained by frequency conversion. Therefore, as described in detail later, synchronization acquisition is performed with a configuration similar to the above after the pulse signal is obtained. This makes it possible to shorten the synchronization acquisition time. In addition, when there is a deviation in the carrier frequency in transmission and reception, as will be described in detail later, the influence of the deviation can be reduced by adding integration processing to the result of cross-correlation, and the time for synchronization acquisition can be shortened. It becomes possible.

  According to the present invention, it is expected to realize a receiving apparatus capable of shortening the time for acquisition of synchronization when a signal is transmitted / received using a pulse train spread by a spreading code.

  Hereinafter, a receiving device and a communication device using the same according to the present invention will be described in more detail with reference to some embodiments shown in the drawings.

<First Embodiment>
A first embodiment of the receiving apparatus of the present invention is shown in FIG. In FIG. 1, 0000 is an antenna, 0110 is an RF front end unit (RFFE), 0120 is a sequential search unit (SRLSRC), 0130 is a code correlation unit (CODECORR), 0140 is a signal detection / synchronization control unit (FIND / SYNCCTL), Reference numeral 0150 denotes a demodulation unit (DEMOD).

  The signal received by the receiving apparatus of the present embodiment with the antenna 0000 is, for example, a BPSK modulated and directly spread pulse train signal transmitted by the transmitting apparatus shown in FIG.

  In FIG. 38, 3510 is an information source (DATA), 3520 is a spread code generator (CODEG), 3530 is a multiplier (MLT), 3540 is a pulse generator (PLSG), and 3550 is a high frequency (hereinafter abbreviated as "RF"). ) Front end part (RFFE), 0000 indicates an antenna.

  The information source 3510 outputs transmission data to be transmitted. Spreading code generation section 3520 outputs a spreading code sequence such as a PN (Pseudo-random Noise) sequence. At this time, the spreading code sequence is generated at a rate higher than the rate at which the information source 3510 generates transmission data. The transmission data output from the information source 3510 by the multiplier 3530 is multiplied by the spreading code sequence generated by the spreading code sequence generating unit 3520 and directly spread to generate a spread data sequence.

  The pulse generation unit 3540 generates a transmission pulse train according to the spread data sequence that is the output of the multiplication unit 3530. At this time, the polarity of the pulse constituting the output pulse train is inverted according to the value of the spread data train. The pulse train generated by the pulse generator 3540 is converted into a transmission signal by being subjected to RF signal processing such as amplification and band limitation by the RF front end 3550, and transmitted from the antenna 0000.

  The RF front end unit 0110 in FIG. 1 receives the BPSK modulated and directly spread pulse train transmitted by the transmission device in FIG. 38 with the antenna 0000, and performs RF signal processing such as amplification, band limitation, and noise removal as necessary. And frequency conversion, and output the received signal.

  The sequential search unit 0120 searches for the time position of the pulse in the received signal. As will be described later, the search is performed based on multiplication of a pulse in the received signal and a pulse of the same period generated by the receiving apparatus. That is, the search is performed by synchronous detection on the received signal. The search result output for each pulse period by the sequential search unit 0120 obtains a cross-correlation value with the spread code by the code correlation unit 0130.

  The signal detection / synchronization control unit 0140 detects the peak value of the cross-correlation value and determines the presence / absence of a signal from the peak value. If it is determined in the determination result that there is no signal, the signal detection / synchronization control unit 0140 controls the next search position in the sequential search unit 0120. At the next time, as will be described later, the search is performed with a slight shift in time, and the search for the time shift is sequentially continued until it is determined whether or not there is a signal.

  In the above determination result, if it is determined that the presence of the signal is present, the synchronization check is performed as necessary, and then the demodulation unit 0150 outputs the cross-correlation value output from the code correlation unit 0130 as the signal detection. Data is demodulated using timing control from the synchronization control unit 0140, and data is output.

  FIG. 2 shows the configuration of FIG. 1 more specifically. In FIG. 2, 0000 is an antenna, 0210 is an RF front end unit (RFFE), 0220 is a sequential search unit that forms a sequential search unit 0120, 0230 is a matched filter (MF) that forms a code correlation unit 0130, and 0240 is signal detection and synchronization. Control unit (FIND / SYNCCTL), 0250 is demodulation unit (DEMOD), 0221 is multiplication unit (MLT), 0222 is integration unit or LPF (Low Pass Filter) unit (integration filter unit) (INT / LPF), 0223 is sampling (SAMP), 0224 indicates a timing signal generator (TMSIGG), and 0225 indicates a template pulse generator (TEMPPLSG).

  The antenna 0000 and the RF front end unit 0210 have functions equivalent to the antenna 0000 and the RF front end unit 0110 in FIG. 1, respectively.

  FIG. 3 shows a synchronization acquisition procedure executed by each unit. 2 will be described below with reference to the procedure shown in FIG.

  A reception signal S0210 is output from the RF front end unit 0210. A template pulse S0225 of 2 information units (2 bits) is generated and output from the template pulse generator 0225 (procedure 0301). In the multiplier 0221, the received signal S0210 is multiplied by the template pulse S0225, and in the integrator or LPF unit 0222, the multiplication result S0221 is integrated or the high frequency component is removed, and the pulse correlation signal S0222 is output (procedure 0302). The template pulse generation unit 0225 generates a template pulse S0225 in synchronization with the timing clock S0224a from the timing signal generation unit 0224 and outputs the template pulse S0225 to the multiplication unit 0221. The integration reset timing of the integration unit 0222 is controlled by the timing clock SO224b from the timing signal generation unit 0224.

  Unlike the template waveform sequence S3660 generated from the template waveform sequence generation unit 3660 shown in FIG. 39, the template pulse S0225 generated from the template pulse generation unit 0225 is a pulse sequence having the same polarity. The template pulse S0225 is a reference pulse used for pulse synchronization with a pulse train based on a spread code of a received signal.

  In the sampling unit 0223, the pulse correlation signal S0222 is sampled and quantized at the same sampling timing as the generation timing of the template pulse S0225. The sampling timing is controlled by a timing clock S0224c output from the timing signal generator 0224.

  The quantized signal is input to the matched filter 0230 (procedure 0303), and the cross-correlation with the spreading code is calculated.

  An example of the configuration of the matched filter 0230 is shown in FIG. In FIG. 4, 0401 is a delay circuit with a delay amount D, 0402 is a multiplier circuit, and 0403 is an adder circuit. D represents a one-sample delay, and c1 to cNs represent code coefficients associated with the spread code sequence. When the spreading code sequence length is 4, Ns = 4.

  FIG. 5 shows an operation example of such a matched filter 0230. This is a case where the spreading code sequence length is 4 (Ns = 4), and s1, s2, s3, and s4 correspond to the signals s1, s2, s3, and s4 in FIG. If the spread code sequence applied to the received signal is {1, 1, -1, 1}, the code coefficients c1 to c4 in FIG. 4 are {c1, c2, c3, c4} = {1, 1, -1,1}. For example, it is assumed that a signal such as {-1, 1, 1, 1, -1, 1, 1, 1} is input as the sampling output s0223. Each signal shifts within the delay sequence in sample time units. Each shifted signal is multiplied with a code coefficient and added to output correlation values S0230a and S0230b at each time. By performing this operation for one information unit (bit) section, the cross-correlation with the spreading code is obtained. However, when 0 is input before a meaningful signal (initial value is 0), the cross-correlation value is not output correctly for the first one information unit (bit) time. To obtain the correlation, 2 information units (2 bits) are required.

  2 and 3, the signal detection / synchronization control unit 0240 detects the peak value of the cross-correlation value S0230a output from the matched filter 0230 (procedure 0304), and calculates the peak value and a preset threshold value. A comparison is made (procedure 0305).

  When the peak value of the cross-correlation value is smaller than the threshold value, the signal detection / synchronization control unit 0240 determines that no signal exists, and sends a timing shift control signal S0240a to the timing signal generation unit 0224. The timing signal generator 0224 shifts the output timing of the timing clocks S0224a, S0224b, S0224c according to the timing shift control signal S0240a (procedure 0306), and then returns to step 0301 to continue the next synchronization acquisition procedure. It is done.

  When the cross correlation peak value is larger than the threshold value (step 0305), the signal detection / synchronization control unit 0240 performs a synchronization check as necessary, and then enters a tracking mode. Correlation value S0230b is passed to demodulation section 0250, and data demodulation is performed using timing control signal S0240b from signal detection / synchronization control section 0240.

  The timing clocks generated by the timing signal generation unit 0224 and input to the template pulse generation unit 0225, the integration unit 0222, and the sampling unit 0223 have the same period. Then, at the stage when the synchronization acquisition is completed, the output timing is maintained at the timing at which the pulse correlation signal becomes the largest.

  Details of the synchronization acquisition operation will be described with reference to FIGS. 6 and 7 show the waveforms of each part of the sequential search unit 0220. From the top, the reception signal S0210 output from the RF front end unit 0210, the template pulse S0250, the output S0221 of the multiplication unit 0221, and the integration unit 0222 are shown. Output S0222 and sampling output S0223 of the sampling unit 0223, and the horizontal axis indicates time.

  FIG. 6 shows a case where the timing of the pulse of the reception signal S0210 and the timing of the template pulse S0250 match, and the sampling output S0223 has a value corresponding to the reception signal.

  FIG. 7 shows a case where the timing of the pulse of the received signal S0210 and the timing of the template pulse S0250 do not match, and only the noise component is output as the sampling output.

  FIG. 8 shows a waveform image at the time of the synchronization acquisition. In FIG. 8, one information unit (bit) is expressed by 4 pulses for the sake of explanation. In a typical communication system, one information unit (bit) is usually expressed by several hundred pulses and is not limited.

  In FIG. 8, the reception signal S0210 output from the RF front end unit 0210, the template pulse S0250, the sampling output S0223 output from the sampling unit 0223, and the output S0230a of the matched filter 0230 are shown in order from the top.

  In FIG. 8, since the position of the pulse of the received signal S0210 and the position of the template pulse S0250 are shifted in the initial state, only the noise component is output from the output S0223 of the sampling unit 0224. In this case, the timing of the template pulse S0250 is shifted, and when the pulse position of the received signal S0210 coincides with the timing of the template pulse S0250 by shifting by Δ, the sampling output S0223 has a value corresponding to the received signal S0210. The sampling output S0223 is input to the matched filter 0230. As a result, the cross-correlation value S0230a with the spreading code is output, and the peak value is output when the correlation with the spreading code is the highest.

  As in the above example, a case where a signal is transmitted at a transmission rate of 250 kbps with a pulse width of 2 nanoseconds is taken. When 1 bit is 128 pulses and directly spread, the timing of both pulses coincides. The maximum number of searches (shifts) until the correlation output is maximized is given by 4 microseconds / 128 / 0.5 nanoseconds, and is about 63 times. However, as described with reference to FIGS. 4 and 5, since it takes 2 information units (2 bits) time to obtain a complete cross-correlation value, the maximum value of the search time is 126 bits. Thus, the synchronization acquisition time can be greatly reduced compared to the above-mentioned 8000 bits.

  FIG. 9 shows a configuration example of the timing signal generation unit 0224. The timing signal generation unit 0224 includes a variable frequency timing clock generator (VFRQCLKG) 0901 and a timing adjuster (TIMAJ) 0902.

  The output timing is controlled by temporarily increasing or decreasing the frequency of the timing clock S0224a output from the timing clock generator 0901 in accordance with the timing shift control signal S0240a of the signal detection / synchronization control unit 0240. The timing clock S0224a is a reference clock for pulse generation timing of the template pulse generation unit 0225. Further, the timing clock S0224a is a timing clock for determining the reset timing S0224b of the integrating unit 0222 and the sampling timing S0224c of the sampling unit 0223 via the timing adjuster 0902.

  FIG. 10 shows another configuration example of the timing signal generation unit 0224. In FIG. 10, reference numeral 1001 denotes a reference clock generator (REFCLKG), 1002 denotes a programmable frequency divider (PRGDIV), and 1003 denotes a timing adjuster (TIMAJ). The timing adjuster 1003 has a function equivalent to that of the timing adjuster 0903 in FIG. The programmable frequency divider 1002 has a function of changing the frequency division number by an external control signal.

  A clock signal having a relatively high frequency is output from the reference clock generator 1001, and is divided to an appropriate frequency by the programmable frequency divider 1002, and becomes a timing clock S0224a that determines the pulse generation timing of the template pulse generator 0225. . Further, the timing clock S0224a is a timing clock for determining the reset timing S0224b of the integrating unit 0222 and the sampling timing S0224c of the sampling unit 0223 via the timing adjuster 1003.

  FIG. 11 shows examples of clock waveforms in FIG. In FIG. 11, the reference clock S1001 that is the output of the reference clock generator, the control signal S0240a from the signal detection / synchronization control unit 0240, and the output S0224a of the programmable frequency divider 1002 are shown in order from the top.

  The programmable frequency divider 1002 has a function of dividing by the frequency division number J + 1 when the normal frequency division number is J and the control signal S0240a is at the high level. In the case of such a configuration, when the timing shift control signal S0240a of the signal detection / synchronization control unit 0240 goes high once, the timing is delayed and shifted by one cycle of the reference clock. Therefore, the period of the reference clock corresponds to one shift width δ of the template pulse. If the interval between pulses is Tw, Tw = J × δ.

  FIG. 12 shows a configuration example of the signal detection / synchronization control unit 0240. In FIG. 12, 1201 is a peak detection unit (PEAK), 1202 is a threshold comparison unit (THR), 1203 is a control signal generation unit (CTLSIGG), 1204 is a control / holding unit (CTL / MEM), and 1205 is a synchronization check unit ( SYNCCK) and 1206 denote a timing control signal generator (TMCTLSIGG).

  The peak detection unit 1201 detects the peak value of the matched filter output S0230a within a predetermined period and the time thereof, and the control / holding unit 1204 holds both. The threshold value comparison unit 1202 compares the peak value with the threshold value, and if the peak value does not exceed the threshold value, the control signal generation unit 1203 outputs the control signal S0240a to the timing signal generation unit 0224.

  When the peak value exceeds the threshold value, the mode shifts to the synchronization check mode, and the synchronization check unit 1205 performs the synchronization check. As an example of the synchronization check, the matched filter output S0230a at the timing when the peak value is detected is compared with the threshold value a predetermined number of times, and if the threshold value is continuously exceeded, the synchronization acquisition is completed with the synchronization check as a pass. Thereafter, the timing control signal generator 1206 generates a timing control signal S0240b for controlling the demodulator 0250 at the above timing.

  FIG. 13 shows an example of a synchronization acquisition procedure using the signal detection / synchronization control unit 0240 configured as described above. First, the signal detection / synchronization control unit 0240 initializes each variable (procedure 1301). For example, the initial generation timing (T = Tini) of the template pulse S0225 and the number of synchronization checks (N = 0) are set. Further, the determination threshold value (Vth) at the time of signal detection may be a predetermined fixed value, or may be set according to the external environment such as noise.

  Next, the peak detection unit 1201 detects the peak value (Vp) and the time (Tp) of the matched filter output S230a within a predetermined period (typically one information unit section), and the control / holding unit 1204 Hold them (procedure 1302).

  Subsequently, the threshold comparison unit 1202 compares Vp and Vth (procedure 1303), and when Vp> Vth, the synchronization check unit 1205 examines the value of N (procedure 1304), and N == K (K is a constant). Then, the synchronization acquisition is completed. When N <K, 1 is added to N (procedure 1305), the matched filter output S0230a after time Ts (Ts is a constant) from time Tp is set to Vp, and the procedure returns to step 1303.

  In step 1303, if Vp <Vth, N = 0 is initialized, and the control signal generation unit 1203 outputs a control signal S0240a that shifts the generation timing of the template pulse S0225 by δ, and returns to step 1302.

  In the above procedure, the constant K indicates the number of synchronization checks. The constant Ts typically takes a spreading code unit time or a value that is an integral multiple of the spreading code unit time.

  FIG. 14 shows another example of the synchronization acquisition procedure using the signal detection / synchronization control unit 0240 configured as described above. First, the signal detection / synchronization control unit 0240 initializes each variable (procedure 1401). For example, the initial generation timing (T = Tini) of the template pulse S0225, the number of synchronization checks (N = 0), and the output point time (M = Mini) of the matched filter 230 are set. Further, the determination threshold value (Vth) at the time of signal detection may be a predetermined fixed value, or may be set according to the external environment such as noise.

  Next, the threshold value comparison unit 1202 sets the value of the matched filter output S0230a at time T + M to Vp (procedure 1402) and compares it with Vth (procedure 1403). If Vp <Vth, the value of N is checked (step 1408). If N> 0, each variable is initialized (N = 0, M = Mini), and the control signal generator 1203 generates the template pulse S0225. A control signal S0240a that shifts the timing by δ (T = T + δ) is output, and the procedure returns to step 1302.

  If N == 0 in step 1408, if M <Ns in step 1409, the matched filter output time is set to M = M + Tc (Tc is a constant) (step 1410), and the process returns to step 1402. If M == Ns, The procedure 1411 is performed, and the procedure returns to the procedure 1402.

  In step 1403, when Vp> Vth, the control / holding unit 1204 holds the output time of Vp at Tp, the synchronization check unit 1205 checks the value of N (step 1405), and N == K (K is a constant) ), The synchronization acquisition is completed. When N <K, 1 is added to N (procedure 1406), the matched filter output S0230a after time Ts (Ts is a constant) from time Tp is set to Vp (procedure 1407), and the process returns to procedure 1403.

  In the above procedure, the constant K indicates the number of synchronization checks, and the constant Ns indicates the spreading code length. The constant Ts typically takes a spreading code unit time or a value that is an integral multiple of the spreading code unit time.

  As described above, since peak detection is not necessary, the hardware configuration is simplified. The probability of hardware configuration simplification can be obtained by applying to a case where peak detection is not performed or false detection is increased, but is applied at a relatively high signal-to-noise ratio. It is valid.

  In the procedure described with reference to FIGS. 13 and 14, the pulse timing shift width δ is not necessarily fixed during one sequence. For example, it is possible to randomly assign δ to one pulse timing shift.

  Furthermore, δ can be determined based on a predetermined algorithm. An example of a synchronization acquisition procedure employing such an algorithm is shown in FIG. The procedure in FIG. 15 is realized by a two-step search.

  First, the signal detection / synchronization control unit 0240 initializes each variable (procedure 9701). For example, the initial generation timing (T = Tini) of the template pulse and the number of synchronization checks (N = 0) are set. The determination threshold values (Vth1, Vth2) at the time of signal detection may be fixed values set in advance, or may be set according to the external environment such as noise.

  Next, the peak detection unit 1201 detects and holds the peak value (Vp) and the time (Tp) of the matched filter output S230a within the predetermined period Tm1 (procedure 9702).

  Subsequently, the threshold comparison unit 1202 compares Vp and Vth1 (procedure 9703), and when Vp> Vth1, the second step search is started (procedure 9704). If Vp <Vth in step 9703, the control signal generation unit 1203 outputs a control signal S0240a that shifts the generation timing of the template pulse by δ1, and returns to step 9702.

  In step 9704, the signal detection / synchronization control unit 0240 resets the generation timing of the template pulse, and the peak detection unit 1201 determines the peak value (Vp) of the matched filter output S230a within the predetermined period Tm2 and the time (Tp). Detect and hold (procedure 9705).

  Next, the threshold comparison unit 1202 compares Vp and Vth2 (procedure 9706), and if Vp> Vth2, the synchronization check unit 1205 examines the value of N (procedure 9707), and N == K (K is a constant) ) Completes synchronization acquisition. If N <K, 1 is added to N (procedure 9708), the matched filter output S0230a after time Ts (Ts is a constant) is set to Vp, and the procedure returns to step 9706.

  In step 9706, when Vp <Vth, N = 0 is initialized, and the control signal generation unit 1203 outputs a control signal S0240a that shifts the generation timing of the template pulse by δ2, and returns to step 9705.

  In the above procedure, the constant K indicates the number of synchronization checks. The constant Ts typically takes a spreading code unit time or a value that is an integral multiple of the spreading code unit time.

  Further, in the above procedure, the timing shift widths δ1 and δ2 and the correlation times Tm1 and Tm2 of the matched filter are different from each other, or only one of the timing shift width and the correlation time is different.

  As described above, when the timing shift widths δ1 and δ2 are different from each other, there is a possibility that the synchronization acquisition time can be shortened in a strong multipath environment. That is, it is possible to reduce the average synchronization acquisition time by setting δ1> δ2 and searching for a block of incoming multipath signals in the first step and searching for the strongest path in the second step.

  Further, in an environment where the signal-to-power noise ratio is good, the correlation time Tm1 <Tm2 of the matched filter is used to search for a signal with a small correlation time in the first search, and at the candidate point where the signal exists, the second step Therefore, the average synchronization acquisition time can be shortened.

  The receiving device that realizes the above procedure can be configured by hardware. Alternatively, an arithmetic processing unit (CPU) or a digital signal processing unit (DSP) and a program containing the above procedure can be used so that the arithmetic processing unit or the digital signal processing unit operates according to the program.

  In addition, in the configuration in which the synchronization acquisition time is 8000 bits as described above, time control with high accuracy is necessary, and if all are realized by analog circuits, there is a problem that the complexity increases and the cost increases. Further, if all control is to be realized in the digital domain, it is necessary to perform sampling with a time resolution higher than the pulse width, resulting in an increase in hardware area and power consumption.

  On the other hand, in the present invention, the time position matching between the received signal pulse and the signal pulse generated on the receiving side can be performed by the sequential search method, and the phase of the spread code can be matched in the digital domain. The apparatus can be configured with relatively simple hardware.

  According to this embodiment, it is expected to realize a receiving apparatus that can shorten the synchronization acquisition time and has a simple configuration.

<Second Embodiment>
A second embodiment of the receiving apparatus of the present invention is shown in FIG. The present embodiment is another configuration example more specifically showing the configuration of FIG. In the configuration of FIG. 16, the multiplication unit 0221 and the integration unit 0222 provided in the configuration of FIG. 2 are omitted.

  In FIG. 16, 0000 is an antenna, 1510 is an RF front end unit (RFFE), 1520 is a sequential search unit (SRLSRC) that forms a sequential search unit 0120, 1521 is a sampling unit (SAMP), and 1522 is a timing signal generation unit (TMSIGG). , 1530 denotes a matched filter (MF) constituting the code correlation unit 0130, 1540 denotes a signal detection / synchronization control unit (FIND / SYNCCTL), and 1550 denotes a demodulation unit (DEMOD).

  The antenna 0000 and the RF front end unit 1510 have the same functions as the antenna 0000 and the RF front end unit 0110 in FIG.

  Further, the timing signal generation unit 1522 and the signal detection / synchronization control unit 1540 have the same functions as the timing signal generation unit 0224 and the signal detection / synchronization control unit 0240 in FIG.

  The reception signal output from the RF front end unit 1510 is sampled and quantized by the sampling unit 1521 with reference to the timing clock output from the timing signal generation unit 1522.

  The quantized signal is input to the matched filter 1530, and the cross-correlation with the spreading code is calculated. The matched filter 1530 has the same function as the matched filter 0230 in FIG.

  The signal detection / synchronization control unit 1540 detects the peak value of the cross-correlation value output from the matched filter 1530 and compares the peak value with a preset threshold value.

  When the peak value of the cross-correlation value is smaller than the threshold value, it is determined that there is no signal, and a timing shift control signal is sent to the timing signal generator 1522. The timing signal generation unit 1522 shifts the output timing according to the timing shift control signal and generates a timing clock.

  If the cross-correlation peak value is larger than the threshold value, after performing a synchronization check as necessary, the cross-correlation value, which is the output of the matched filter 1530, is then passed to the demodulator 1550 for signal detection / synchronization control Data is demodulated using the timing control signal from unit 1540.

  In this embodiment, the sequential search unit 1520 eliminates the need for the multiplication unit 0221 and the integration unit 0222 provided in the configuration of FIG. The complexity for operating the generation unit, integration unit, and sampling unit in synchronization with high accuracy can be eliminated.

  In this embodiment, since the noise suppression effect by the multiplication unit and the integration unit cannot be obtained, this embodiment is used when reception is performed at a relatively high signal-to-noise ratio compared to the case of the first embodiment. It is suitable to apply.

<Third Embodiment>
A third embodiment of the receiving apparatus of the present invention is shown in FIG. This embodiment is applied to a communication system that transmits a signal using a modulated pulse waveform obtained by modulating a carrier wave with a pulse waveform as shown in the upper part of FIG. In FIG. 17, 0000 is an antenna, 1610 is an RF front end unit (RFFE), 1620 is a frequency conversion unit (FRQCONV), 1630 is a sequential search unit (SRLSRC), 1640 is a code correlation unit (CODECORR), 1650 is a signal detection A synchronization control unit (FIND / SYNCCTL) and 1660 denote a demodulation unit (DEMOD).

  The signal received in the present embodiment is, for example, a transmission signal generated in the transmission apparatus shown in FIG. 38 described above. That is, in the information source 3510, the signal (data) is divided into an in-phase component (I component) and a quadrature component (Q component), and the spreading code generation unit 3520, the multiplication unit 3530, and the pulse generation unit 3540 respectively perform BPSK modulation and direct A spread pulse train is generated. Further, in the front end unit 3550, a transmission signal having a modulated pulse waveform is generated by modulating the carrier wave with the same pulse train, and is transmitted from the antenna 0000.

  The RF front end unit 1610 receives the transmission signal with the antenna 0000, performs RF signal processing such as amplification, band limitation, and noise removal as necessary, and outputs a reception signal S1610.

  The frequency converter 1620 divides the received signal S1610 of the modulated pulse waveform into two orthogonal components, an I component and a Q component, and performs frequency conversion on each to extract the original pulse waveforms S1620I and S1620Q.

  The sequential search unit 1630 searches for the time positions of the pulse waveforms S1620I and S1620Q of the I component and Q component. For the search results S1630I and S1630Q of the sequential search unit 1630 output for each pulse period for each component, the code correlation unit 1640 obtains a cross-correlation value with the spread code.

  The signal detection / synchronization control unit 1650 detects the peak value by combining the cross-correlation values S1640a of the two components, and determines the presence / absence of a signal from the peak value. If it is determined in the determination result that there is no signal, the signal detection / synchronization control unit 1650 controls the next search position in the sequential search unit 1630 by the timing control signal 1650a.

  In the above determination result, if it is determined that the signal exists, a synchronization check is performed as necessary, and then the demodulation unit 1660 outputs the cross-correlation value outputs S1640I and S1640Q output from the code correlation unit 1640. The data is demodulated using the timing control signal 1650b from the signal detection / synchronization control unit 1650, and the data is output.

  FIG. 18 shows the configuration of FIG. 17 more specifically. In FIG. 18, 0000 is an antenna, 1710 is an RF front end unit (RFFE), 1720 is a frequency conversion unit forming a frequency conversion unit 1620, 1730 is a sequential search unit forming a sequential search unit 1630, and 1740 is a code correlation unit 1640. A code correlation unit, 1750 is a signal detection / synchronization control unit (FIND / SYNCCTL), and 1760 is a demodulation unit. Further, 1721I and 1721Q are multipliers (MIX), 1722I and 1722Q are LPFs, 1723 is a local signal generator (LO), 1724 is a 90-degree phase shifter (90PH), 1731I and 1731Q are multipliers (MLT), 1732I, 1732Q is an integration unit / LPF unit (INT / LPF), 1733I and 1733Q are sampling units (SAMP), 1734 is a timing signal generation unit (TMSIGG), 1735 is a template pulse generation unit (TEMPOLSG), and 1741I and 1741Q are matched filters ( MF), 1742I and 1742Q are absolute value / squarer (ABS / SQR), and 1743 is an adder (ADD).

  The antenna 0000 and the RF front end unit 1710 have functions equivalent to the antenna 0000 and the RF front end unit 1610 in FIG.

  The timing signal generation unit 1734, template pulse generation unit 1735, and signal detection / synchronization control unit 1750 have the same functions as the timing signal generation unit 0224, template pulse generation unit 0225, and signal detection / synchronization control unit 0240 in FIG. .

  The reception signal output from the RF front end unit 1710 is multiplied by local signals in the multipliers 1721I and 1721Q. This local signal is a signal output from the local signal generator 1723 and output by the 90-degree phase shifter 1724 so that the phases thereof are different from each other by 90 degrees. The high frequency components are removed from the signals multiplied by the multipliers 1721I and 1721Q by the LPFs 1722I and 1722Q, respectively, and the original pulse waveform is extracted.

  Both components of the pulse waveform are multiplied by the template pulses output from the template pulse generator 1735 by the multipliers 1731I and 1731Q, and the integration or high-frequency components are removed by the integrators or LPF units 1732I and 1732Q, and the pulse correlation Signals S1732I and S1732Q are output.

  The template pulse generator 1735 generates a template pulse in synchronization with the timing clock from the timing signal generator 1734 and outputs the template pulse to the multipliers 1731I and 1731Q. The template pulses input to the multipliers 1731I and 1731Q are the same. Further, the integration reset timing of the integrators 1732I and 1732Q is controlled by the timing clock from the timing signal generator 1734.

  Unlike the template waveform sequence generated from the template waveform sequence generation unit 3660 shown in FIG. 39, the template pulse generated by the template pulse generation unit 1735 is a pulse sequence having the same polarity.

  In the sampling units 1733I and 1733Q, the pulse correlation signal is sampled and quantized at the same cycle as the template pulse generation timing. The sampling timing is controlled by a timing clock output from the timing signal generator 1734.

  A timing clock input to the template pulse generator 1735, the integrators 1732I and 1732Q, and the sampling units 1733I and 1733Q is generated by the timing signal generator 1734. Each timing clock signal has the same period, and the output timing is related to a predetermined relationship. That is, the pulse correlation signal output from the matched filters 1741I and 1741Q is controlled at the maximum timing.

  The quantized signals are input to matched filters 1741I and 1741Q, respectively, and the cross-correlation with the spreading code is calculated. The matched filters 1741I and 1741Q have the same function as the matched filter 0230 in FIG.

  The absolute value / square units 1742I and 1742Q obtain absolute values or squares of the I component and Q component of the cross-correlation value, and the adder 1743 obtains the sum of each and obtains the amplitude component of the cross-correlation value.

  The signal detection / synchronization control unit 1750 detects the peak value of the amplitude component of the cross-correlation value output from the adder 1743, and compares the peak value with a preset threshold value.

  When the peak value of the amplitude component of the cross-correlation value is smaller than the threshold value, the signal detection / synchronization control unit 1750 determines that no signal exists and sends a timing shift control signal to the timing signal generation unit 1734. The timing signal generation unit 1734 shifts the output timing according to the timing shift control signal and generates a timing clock.

  If the peak value of the amplitude component of the cross-correlation is greater than the threshold value, the signal detection / synchronization control unit 1750 performs a synchronization check as necessary, and thereafter the cross-correlation value output from the matched filters 1741I and 1741Q is demodulated. The data is demodulated using the timing control signal from the signal detection / synchronization control unit 1750.

  An example of a typical synchronization acquisition procedure is the same as the synchronization acquisition flowchart shown in FIG. 3 in the first embodiment.

  In the present invention, the time position of the received signal pulse and that of the signal generated on the receiving side can be matched by the sequential search method, and the phase of the spread code can be matched in the digital domain. It can be realized with a simple hardware configuration.

  According to this embodiment, when a modulated pulse waveform is used, it is possible to reduce the synchronization acquisition time and to realize a receiving device with a simple configuration.

<Fourth Embodiment>
FIG. 19 shows a fourth embodiment of the receiving apparatus of the present invention. This embodiment is another configuration example that more specifically shows the configuration of FIG. In the configuration of FIG. 19, the multiplication units 1731I and 1731Q and the integration units 1732I and 1732Q that are included in the configuration of FIG. 18 are omitted.

  In FIG. 19, 0000 is an antenna, 1810 is an RF front end unit (RFFE), 1820 is a frequency conversion unit forming a frequency conversion unit 1620, 1830 is a sequential search unit forming a sequential search unit 1630, and 1840 is a code correlation unit 1640. A code correlation unit, 1850 indicates a signal detection / synchronization control unit (FIND / SYNCCTL), and 1860 indicates a demodulation unit (DEMOD). Further, 1821I and 1821Q are multiplication units (MIX), 1822I and 1822Q are LPFs, 1823 is a local signal generation unit (LO), 1824 is a 90-degree phase shifter (90PH), 1831I and 1831Q are sampling units (SAMP), 1832 is Timing signal generators (TMSIGG), 1841I and 1841Q are matched filters (MF), 1842I and 1842Q are absolute value squarers (ABS / SQR), and 1843 is an adder (ADD).

  The antenna 0000 and the RF front end unit 1810 have functions equivalent to the antenna 0000 and the RF front end unit 1610 in FIG.

  Further, the frequency converter 1820 and its constituent elements have functions equivalent to those of the frequency converter 1720 and its constituent elements in FIG.

  The reception signal output from the RF front end unit 1810 is multiplied by local signals in the multiplication units 1821I and 1821Q. This local signal is a signal output from the local signal generator 1823 and output by the 90-degree phase shifter 1824 so that the phases thereof are different from each other by 90 degrees. The high frequency components are removed from the signals multiplied by the multipliers 1821I and 1821Q by the LPFs 1822I and 1822Q, respectively, and the original pulse waveform is extracted.

  Both components of the pulse waveform are sampled and quantized by the sampling units 1831I and 1831Q with reference to the timing clock output from the timing signal generation unit 1832.

  The quantized signals are input to matched filters 1841I and 1841Q, respectively, and the cross-correlation with the spreading code is calculated. These matched filters 1841I and 1841Q require the same function as the matched filter 0230 in FIG.

  Absolute value / square units 1842I and 1842Q obtain the absolute value or square of the I component and Q component of the cross-correlation value, and the adder 1843 obtains the sum of each and obtains the amplitude component of the cross-correlation value.

  The signal detection / synchronization control unit 1850 detects the peak value of the amplitude component of the cross-correlation value output from the adding unit 1843, and compares the peak value with a preset threshold value.

  If the peak value of the amplitude component of the cross-correlation value is smaller than the threshold value, the signal detection / synchronization control unit 1850 determines that there is no signal and sends a timing shift control signal to the timing signal generation unit 1832. The timing signal generation unit 1832 shifts the output timing according to the timing shift control signal, and generates a timing clock.

  When the peak value of the cross correlation is larger than the threshold value, the signal detection / synchronization control unit 1850 performs synchronization check as necessary, and the cross correlation value that is the output of the matched filters 1841I and 1841Q is then determined by the demodulation unit 1860. The data is demodulated using the timing control signal from the signal detection / synchronization control unit 1850.

  In this embodiment, in the sequential search unit 1830, the multiplication units 1731I and 1732Q and the integration units 1732I and 1732Q provided in the configuration of FIG. 18 are no longer necessary, so the scale of the analog unit is reduced when mounted. Moreover, the complexity for operating the template pulse generator, the integrator, and the sampling unit in synchronization with high accuracy can be eliminated.

  In this embodiment, since the noise suppression effect by the multiplication unit and the integration unit cannot be obtained, this embodiment is used when reception is performed at a relatively high signal-to-noise ratio compared to the case of the third embodiment. It is suitable to apply.

<Fifth Embodiment>
A fifth embodiment of the receiving apparatus of the present invention is shown in FIG. This embodiment is still another configuration example that more specifically shows the configuration of FIG.

  In FIG. 20, 0000 is an antenna, 1910 is an RF front end unit (RFFE), 1920 is a frequency conversion unit forming a frequency conversion unit 1620, 1930 is a sequential search unit forming a sequential search unit 1630, and 1940 is a code correlation unit 1640. A code correlation unit, 1950, a signal detection / synchronization control unit (FIND / SYNCCTL), and 1960, a demodulation unit (DEMOD). Further, 1921I and 1921Q are multiplication units (MIX), 1922I and 1922Q are LPFs, 1923 is a local signal generation unit (LO), 1924 is a 90-degree phase shifter (90PH), 1931I and 1931Q are multiplication units (MLT), 1932I , 1932Q is an integration unit or LPF unit (INT / LPF), 1933I and 1933Q are sampling (SAMP) units, 1934 is a timing signal generation unit (TMSIGG), 1935 is a template pulse generation unit (TEMPPLSG), 1941I and 1941Q are matched filters (MF), 1942I and 1942Q are absolute value / squarer (ABS / SQR), 1943 is an adder (ADD), and 1944 is an in-phase integrator (INPHINT).

  The antenna 0000 and the RF front end unit 1910 have the same functions as the antenna 0000 and the RF front end unit 1610 in FIG.

  Further, the timing signal generation unit 1934, the template pulse generation unit 1935, and the signal detection / synchronization control unit 1950 have the same functions as the timing signal generation unit 0224, the template pulse generation unit 0225, and the signal detection / synchronization control unit 0240 in FIG. Have.

  The reception signal output from the RF front end unit 1910 is multiplied by the local signal in the multiplying units 1921I and 1921Q. This local signal is a signal output from the local signal generator 1923 and output by the 90-degree phase shifter 1924 so that the phases thereof are different from each other by 90 degrees. From the signals multiplied by the multipliers 1921I and 1921Q, the high frequency components are removed by the LPFs 1922I and 1922Q, respectively, and the original pulse waveform is extracted.

  Both components of the pulse waveform are multiplied by the template pulses output from the template pulse generator 1935 by the multipliers 1931I and 1931Q, and the integration or high-frequency components are removed by the integrators or LPF units 1932I and 1932Q, and the pulse correlation Signals S1932I and S1932Q are output.

  The template pulse generation unit 1935 generates a template pulse in synchronization with the timing clock from the timing signal generation unit 1934, and outputs it to the multiplication units 1931I and 1931Q. The template pulses input to the multipliers 1931I and 1931Q are the same. The integration reset timings of the integrators 1932I and 1932Q are controlled by the timing clock from the timing signal generator 1934.

  Unlike the template waveform sequence generated from the template waveform sequence generation unit 3660 shown in FIG. 39, the template pulses generated from the template pulse generation unit 1935 are all pulse sequences having the same polarity.

  In the sampling units 1933I and 1933Q, the pulse correlation signals S1932I and S1932Q are sampled and quantized at the same cycle as the template pulse generation timing. The sampling timing is controlled by a timing clock output from the timing signal generator 1934.

  Each timing clock input to the template pulse generator 1935, the integrators 1932I and 1932Q, and the sampling units 1933I and 1933Q is generated by the timing signal generator 1935. Each timing clock signal has the same period, and the output timing is related to a predetermined relationship.

  The quantized signals are input to matched filters 1941I and 1941Q, respectively, and the cross-correlation with the spreading code is calculated. The matched filters 1941I and 1941Q have the same function as the matched filter 0230 in FIG.

  The absolute value / square units 1942I and 1942Q obtain absolute values or squares of the I component and Q component of the cross-correlation value, and the adder 1943 obtains the sum of them to obtain the amplitude component of the cross-correlation value. Further, the in-phase integrator 1944 adds the amplitude components of the cross-correlation values a predetermined number of times with the same phase. That is, a predetermined number of times are added to each component of the amplitude component of the cross-correlation value.

  The signal detection / synchronization control unit 1950 detects the peak value of the integral value of the amplitude component of the cross-correlation value output from the in-phase integration unit 1944, and compares the peak value with a preset threshold value.

  When the peak value of the amplitude component of the cross-correlation value is smaller than the threshold value, the signal detection / synchronization control unit 1950 determines that no signal exists and sends a timing shift control signal to the timing signal generation unit 1934. The timing signal generation unit 1934 generates a timing clock by shifting the output timing in accordance with the timing shift control signal.

  If the peak value of the amplitude component of the cross-correlation is greater than the threshold value, the signal detection / synchronization control unit 1950 performs a synchronization check as necessary, and thereafter the cross-correlation value output from the matched filters 1941I and 1941Q is demodulated. Passed to part 1960. Demodulation section 1960 performs synchronization (bit synchronization) in one information unit (bit) time using the timing control signal from signal detection / synchronization control section 1950, and then data is demodulated.

  In the case of adopting the above configuration, as shown in FIG. 21, the spreading code applied to the transmission signal at the time of synchronization acquisition has a sequence length of 1 / m compared to the number of pulses per information unit (bit) at the time of data transmission. It is assumed that That is, the number of pulses per information unit (bit) is m times the sequence length of the pulse synchronous spreading code. Matched filters 1941I and 1941Q in FIG. 20 have delay numbers and coefficient sequences corresponding thereto.

  FIG. 22 shows a configuration example of demodulation section 1960 with the above configuration and when transmission data is differentially encoded in units of spreading sequences. In FIG. 22, 2111I and 2111Q are signal selectors (SELCT), 2112I and 2112Q are delay units (DELAY), 2113I and 2113Q are multipliers (MLT), 2114 is an adder, 2115 is an integrator (INT), and 2116 is A determination unit (JUDG) and 2117 indicate a bit synchronization unit (BITSYNC).

  Based on the cross-correlation values from the matched filters 1941I and 1941Q, the signal selection units 2111I and 2111Q select the synchronization point output using the timing control signal from the signal detection / synchronization control unit 1950. The extracted signal is delayed by one spreading code unit with a delay of 2112I and 2112Q. The delayed signal and the undelayed signal are multiplied in the multipliers 2113I and 2113Q. Outputs from the multiplication units 2113I and 2113Q of the I and Q quantity components are added by the addition unit 2114. Thereafter, the integration unit 2115 integrates m times, and then the determination unit 2116 discriminates data and demodulates. Prior to demodulation, the bit synchronization unit 2117 performs bit synchronization in units of information so that the determination error probability in the determination unit 2117 is minimized.

  FIG. 23 shows an example of the synchronization acquisition procedure when the demodulator 1960 has the configuration shown in FIG. In step 2201, pulse synchronization and spreading code unit synchronization are first performed. An example of the sequence in this procedure 2201 is shown in the same procedure as in FIGS. Next, in step 2202, bit synchronization is performed and demodulation is started.

  FIG. 24 shows another configuration example of the demodulator 1960. 24, 2311I and 2311Q are signal selection units (SELCT), 2312 is a phase error / frequency correction unit (PHDIFF / REQDIF), 2313 is a phase rotation unit (PHROTA), and 2314 is a bit synchronization / judgment unit (BITSYNC / JUDG). Indicates.

  The signal selection units 2311I and 2311Q select the synchronization point output using the cross-correlation values from the matched filters 1941I and 1941Q using the timing control signal from the signal detection / synchronization control unit 1950.

  The phase error / frequency correction unit 2312 extracts an initial phase and a frequency deviation using the output, and calculates a phase rotation amount for correction. The phase rotation unit 2313 rotates the phase on the I and Q planes by the amount of phase rotation described above, and outputs the result to the determination unit 2314. Then bit synchronization. The determination unit 2314 performs bit synchronization and data determination.

  An example of the synchronization acquisition procedure when the configuration of FIG. 24 is adopted is shown in FIG. In step 2401, pulse synchronization and spreading code unit synchronization are first performed. An example of the sequence in this procedure 2401 is shown in the same procedure as in FIGS. Next, in step 2402, initial phase estimation and frequency deviation estimation are performed. Thereafter, bit synchronization is performed and demodulation is started.

  As in the above-described configuration, the correlation value is obtained by dividing one information unit time into m, and after obtaining the amplitude component and then integrating m times, the influence of the amplitude fluctuation of the pulse waveform shown in the lower part of FIG. Can be reduced. The amplitude variation of the pulse waveform occurs after frequency conversion when there is a frequency deviation in the carrier wave between transmission and reception.

  FIG. 26 shows how the influence of the amplitude fluctuation of the pulse waveform is reduced. The upper part of FIG. 26 shows the envelopes of the converted pulse waveforms S1932I (S1732I) and S1932Q (S1732Q) when there is a frequency deviation, and the lower part shows the correlation output. For simplicity, it is assumed that no spreading code is applied in the upper stage. At this time, in the configuration of FIG. 18, since the correlation value is an integral value of one information unit (bit) time of the upper signal, the influence of the fluctuation of the amplitude becomes large, and the code correlation is as shown in the lower curve. The output of the unit 1740, that is, the amplitude component (S1743) of the correlation value output from the adding unit 1743 is small.

  With the configuration shown in FIG. 20, since the integration interval is shortened, the influence of fluctuations in amplitude can be reduced, and the output of the code correlation unit 1940, that is, the output of the in-phase integration unit 1944, as in the lower stepped waveform. Correlation output (S1944) is improved.

  FIG. 27 shows the result of confirming the above effect by computer simulation. In FIG. 27, the horizontal axis indicates energy per bit power noise density (Eb / N0), and the vertical axis indicates the signal acquisition time required to obtain an acquisition probability of 1% on the basis of one information unit (bit). is there. The transmission rate is 250 kbps, the interval between pulses is 32 nanoseconds, and the frequency deviation is assumed to be 40 ppm. From FIG. 27, the signal acquisition time is significantly reduced when m = 4 with respect to the division number m = 1.

  Further, the division number m with respect to the number of pulses per information unit (bit) of the spread code sequence length of the transmission signal at the time of synchronization acquisition, and the number of integrations n in the in-phase integration unit 1944 are as described above. In, it is in agreement, but both may be different. For example, when the number of integrations is n = 2 × m by dividing into m, the signal-to-power noise ratio of the signal input to the signal detection / synchronization control unit 1950 is improved, and the synchronization acquisition probability is improved.

  Since the sequence length of the spreading code is 1 / m compared to the number of pulses per information unit (bit), the spreading code per information unit (bit) has periodicity and the randomness is lowered. . Therefore, interference with other communication systems increases. Therefore, this embodiment is suitable for application when the distance from other communication systems is relatively long and the influence of interference is reduced.

<Sixth Embodiment>
FIG. 28 shows a sixth embodiment of the receiving apparatus of the present invention. This embodiment is still another configuration example that more specifically shows the configuration of FIG. In the configuration of FIG. 28, the multiplication units 1931I and 1931Q and the integration units 1932I and 1932Q provided in the configuration of FIG. 20 are omitted.

In FIG. 28, 0000 is an antenna, 2710 is an RF front end unit (RFFE), 2720 is a frequency conversion unit forming a frequency conversion unit 1620, 2730 is a sequential search unit forming a sequential search unit 1630, and 2740 is a code correlation unit 1640. A code correlation unit, 2750 is a signal detection / synchronization control unit (FIND / SYNCCTL), and 2760 is a demodulation unit (DEMOD). Furthermore, 2721I and 2721Q are multiplication units (MIX), 2722I and 2722Q are LPFs, 2723 is a local signal generation unit (LO), 2724 is a 90-degree phase shifter (90PH), 2731I and 2731Q are sampling units (SAMP), and 2732 is Timing signal generator (TMSIGG), 2741I and 2741Q are matched filters (MF), 2742I and 2742Q are absolute value squarers (ABS / SQR), 2743 is an adder (ADD), and 2744 is an in-phase integrator (INPHINT) ).
The antenna 0000 and the RF front end unit 2710 have functions equivalent to the antenna 0000 and the RF front end unit 1610 in FIG.

  Further, the timing signal generation unit 2732 and the signal detection / synchronization control unit 2750 have the same functions as the timing signal generation unit 0224 and the signal detection / synchronization control unit 0240 in FIG.

  The reception signal output from the RF front end unit 2710 is multiplied by the local signal in the multiplying units 2721I and 2721Q. This local signal is a signal output from the local signal generator 2723 and output by the 90-degree phase shifter 2724 so that the phases thereof are different from each other by 90 degrees. The high frequency components are removed from the signals multiplied by the multipliers 2721I and 2721Q by the LPFs 2722I and 2722Q, respectively, and the original pulse waveform is extracted.

  Both components of the pulse waveform are sampled and quantized by the sampling units 2731I and 2731Q with reference to the timing clock output from the timing signal generation unit 2732.

  The quantized signals are input to matched filters 2741I and 2741Q, respectively, and the cross-correlation with the spreading code is calculated. The matched filters 2741I and 2741Q have the same function as the matched filter 0230 in FIG.

  The absolute value / square units 2742I and 2742Q calculate the absolute value or the square of the I component and Q component of the cross-correlation value, and the adder 2743 calculates the sum of each, and calculates the amplitude component of the cross-correlation value. Further, the in-phase integrator 2744 adds the amplitude components of the cross-correlation values a predetermined number of times with the same phase. That is, a predetermined number of times are added to each component of the amplitude component of the cross-correlation value.

  The signal detection / synchronization control unit 2750 detects the peak value of the integrated value of the amplitude component of the cross-correlation value output from the in-phase integration unit 2744, and compares the peak value with a preset threshold value.

  When the peak value of the amplitude component of the cross-correlation value is smaller than the threshold value, the signal detection / synchronization control unit 2750 determines that no signal exists and sends a timing shift control signal to the timing signal generation unit 2732. The timing signal generation unit 2732 shifts the output timing in accordance with the timing shift control signal, and generates a timing clock.

  When the peak value of the amplitude component of the cross-correlation is larger than the threshold value, the signal detection / synchronization control unit 2750 performs a synchronization check as necessary, and thereafter the cross-correlation value that is an output of the matched filters 2741I and 2741Q. Is passed to the demodulator 2760. Demodulation section 2760 performs synchronization (bit synchronization) in one information unit (bit) time using the timing control signal from signal detection / synchronization control section 2750, and then performs data demodulation.

  When the above configuration is adopted, the sequence length of the spreading code applied to the transmission signal at the time of acquisition is 1 / m compared to the number of pulses per information unit (bit) at the time of data transmission. . The matched filters 2741I and 2741Q in FIG. 28 have delay numbers and coefficient sequences corresponding to the matched filters 2741I and 2741Q. Then, in-phase integration section 2744 performs m times of integration for each component.

  The demodulator 2760 has a function equivalent to that of the demodulator 1960 in FIG.

  In the sequential search unit 2730 having the configuration shown in FIG. 28, the multiplication units 1931I and 1932Q and the integration units 1932I and 1932Q included in FIG. In addition, the complexity for operating the template pulse generator, the integrator, and the sampling unit in synchronization with high accuracy can be eliminated.

  In this embodiment, since the noise suppression effect by the multiplier and the integrator cannot be obtained, this embodiment is used when reception is performed at a relatively high signal-to-noise ratio compared to the case of the fifth embodiment. It is suitable to apply.

<Seventh Embodiment>
FIG. 29 shows a seventh embodiment of the receiving apparatus of the present invention. The present embodiment is still another configuration example that more specifically shows the configuration of FIG.

  In FIG. 29, 0000 is an antenna, 2810 is an RF front end unit (RFFE), 2820 is a sequential search unit constituting a sequential search unit 0120, 2830 is a matched filter (MF), 2840 is a signal detection / synchronization control unit (FIND / SYNCCTL) 2850 indicates a demodulator (DEMOD). Further, 2821 is a multiplication unit (MLT), 2822 is an integration unit or LPF unit (INT / LPF), 2823 is a sampling unit (SAMP), 2824 is a timing signal generation unit (TMSIGG), and 2825 is a variable template pulse generation unit (VTEMPPLSG). ) Respectively.

  The antenna 000 and the RF front end unit 2810 have the same functions as the antenna 0000 and the RF front end unit 0110 in FIG.

  The reception signal output from the RF front end unit 2810 is multiplied by the template pulse output from the template pulse generation unit in the multiplication unit 2821, and the integration or high-frequency component is removed in the integration unit or the LPF unit 2822, and the pulse correlation A signal is output.

  The variable template pulse generation unit 2825 generates a template pulse S2825 in synchronization with the timing clock S2824a from the timing signal generation unit 2824, and outputs the template pulse S2825 to the multiplication unit 2821. The integration reset timing is controlled by the timing clock from the timing signal generator 2824.

  In the sampling unit 2823, the pulse correlation signal is sampled and quantized at the same cycle as the generation timing of the template pulse. The sampling timing is controlled by a timing clock output from the timing signal generator 2824.

  The timing clock input to the template pulse generation unit 2825, the integration unit 2822, and the sampling unit 2823 is generated by the timing signal generation unit 2824. Each timing clock signal has the same period, and the output timing is related to a predetermined relationship.

  Unlike the template waveform sequence generated from the template waveform sequence generation unit 3660 shown in FIG. 39, the template pulse S2825 generated from the template pulse generation unit 2825 is a pulse sequence having the same polarity.

  The quantized signal is input to the matched filter 2830, and the cross-correlation with the spreading code is calculated. The matched filter 2830 has the same function as the matched filter 0230 in FIG.

  The signal detection / synchronization control unit 2840 detects the peak value of the cross-correlation value output from the matched filter 2830, and compares the peak value with a preset threshold value.

  When the peak value of the cross-correlation value is smaller than the threshold value, the signal detection / synchronization control unit 2840 determines that no signal exists, and sends a timing shift control signal to the timing signal generation unit 2824. The timing signal generation unit 2824 shifts the output timing according to the timing shift control signal and generates a timing clock.

  When the peak value of the cross correlation is larger than the threshold value, the signal detection / synchronization control unit 2840 sends a control signal S2840a to the variable template pulse generation unit 2825 to change the waveform of the template pulse. Thereafter, the receiving apparatus performs the same operation as described above.

  If the peak value of the cross-correlation value is greater than a preset threshold value after the receiving apparatus repeats the above operation a predetermined number of times, the signal detection / synchronization control unit 2840 determines that a signal exists and A synchronization check is performed, and the cross-correlation value that is the output of the matched filter 2830 is passed to the demodulator 2850. Demodulation section 2850 performs data demodulation using the timing control signal from signal detection / synchronization control section 2840.

  FIG. 30 shows a configuration example of the variable template pulse generator 2825. Reference numeral 2911 denotes a template pulse generator 1 (TEMPPLSG1), and 2912 denotes a template pulse generator 2 (TEMPPLSG2).

  Based on the template pulse waveform control signal S2840a from the signal detection / synchronization control unit 2840, it is selected whether to use the template pulse generation unit 12911 or the template pulse generation unit 22912. The selected template pulse generator 12911 or template pulse generator 22912 uses the timing clock S2824a from the timing signal generator 2824 to generate and output a template pulse S2825.

  FIG. 31 shows an example of the synchronization acquisition procedure in this case. First, the template pulse generator 12911 is set (procedure 3001), and the first pulse synchronization and spreading code synchronization point is searched (procedure 3002). Thereafter, the setting is changed to the template pulse generator 22912 (procedure 3004), and the second pulse synchronization / spread code synchronization point is searched (procedure 3005).

  FIG. 32 shows an example of the operation waveform. The upper stage shows the received signal, the middle stage shows the first template pulse waveform when the template pulse generation unit 12911 is selected, and the lower stage shows the second template pulse waveform when the template pulse generation unit 22912 is selected. In the pulse waveforms from the template pulse generation units 12911 and 29912, it is desirable that the pulse width generated from the template pulse generation unit 12911 is wider than the pulse width generated from the template pulse generation unit 22912.

  First, the pulse position of the received signal is roughly searched using the first template waveform having a wide width. Next, the second template waveform is used to search for a position where there is a pulse in detail.

  By adopting such a structure, the search position can be moved from a wide place to a narrow place and an efficient search can be performed, so that the synchronization acquisition time can be improved.

  FIG. 33 shows the result of confirming the above effect by computer simulation. In FIG. 33, the horizontal axis shows energy per bit power noise density (Eb / N0), and the vertical axis shows the signal acquisition time required to obtain 1% of the acquisition probability on the basis of one information unit (bit). is there. The transmission rate is 250 kbps, the interval between pulses is 32 nanoseconds, and the pulse width is 2 nanoseconds. As shown in FIG. 33, when a 2 nanosecond rectangular wave is used for the first template pulse waveform and the second template pulse waveform is a transmission pulse waveform (A in FIG. 33), the transmission pulse waveform is used as the template pulse waveform. The signal acquisition time can be reduced as compared with the case of using only (B in FIG. 33).

  In this embodiment, the variable template pulse generator is applied to the first embodiment of FIG. 2, but the variable template pulse generator is the third embodiment of FIG. 17 or the fifth embodiment of FIG. Applicable to form. In that case, the template pulse generator in the third embodiment of FIG. 17 and the fifth embodiment of FIG. 20 is changed to the variable template pulse generator. The variable template pulse generator can also be applied to all communication methods that perform synchronous detection using a template.

  Although the circuit configuration is complicated by using two template pulse generators, this embodiment is suitable for application to a communication system in which reduction of signal acquisition time is particularly important.

<Eighth Embodiment>
FIG. 34 shows an eighth embodiment of the receiving apparatus of the present invention. In the present embodiment, pulse synchronization and bit synchronization of spreading codes are performed separately.

  34, 0000 is an antenna, 9810 is an RF front end unit (RFFE), 9820 is a sequential search unit (SRLSRC), 9830 is a code correlation unit (CODECRR), 9840 is a signal detection / synchronization control unit (FIND / SYNCCTL), Reference numeral 9850 denotes a demodulation unit (DEMOD), and 9860 denotes a power measurement unit (MESPOW).

  The RF front end unit 9810 receives, for example, the BPSK modulated and directly spread pulse train at the antenna 0000 in the transmission device shown in FIG. 38 described above, and performs RF signal processing such as amplification, band limitation, and noise removal as necessary. And frequency conversion, and output the received signal.

  The subsequent operation of each part will be described with reference to an example of the procedure at the time of synchronization acquisition shown in FIG. The sequential search unit 9820 searches for the time position of the pulse in the received signal (procedure 9901). The search result output for each pulse period by the sequential search unit 9820 is input to the power measurement unit 9860, and the average power for a predetermined period is measured (procedure 9902).

  The signal detection / synchronization control unit 9840 determines the presence / absence of a signal based on whether or not the measured average power exceeds a threshold (step 9903). If it is determined in the determination result that there is no signal, the signal detection / synchronization control unit 9840 controls the next search position in the sequential search unit (procedure 9906) and returns to the procedure 9901.

  If it is determined in the determination result that there is a signal, after performing a synchronization check if necessary, the search result is input to the code correlation unit 9830, and a cross-correlation value with the spread code is calculated. (Procedure 9904). The peak value of the cross-correlation value is detected (procedure 9905), and the signal detection / synchronization control unit 0240 enters the tracking mode after performing a synchronization check as necessary. Thereafter, the cross-correlation value is input to the demodulation unit 9850 at the peak timing, and data demodulation is performed.

  In the present embodiment, the synchronization of the pulse position search and the spreading code is performed in a time-divided manner, so that the code correlation unit 9840 is not operated when searching for the pulse position, and a reduction in power consumption can be expected. Further, since the number of elements in the path from the pulse position search to the search position control is reduced, the delay is reduced as compared with the first embodiment, and high-speed control is possible. However, this embodiment is effective in an environment where the signal power to noise power ratio is good because the noise characteristics are worse than those of the first embodiment.

  Here, FIG. 36 shows an example of a communication device (transmission / reception device) using any of the reception devices of the first to eighth embodiments according to the present invention.

  In FIG. 36, 0000 is an antenna, 3301 is a switch (SW), 3302 is a UWB transmitter (UWBTX), 3303 is a UWB transmitter (UWBRX), 3304 is a baseband unit (BB), and 3305 is an application unit (APL). Show. The baseband unit 3304 receives data to be transmitted from the application unit 3305, performs baseband processing, and generates transmission data. The UWB transmitter 3302 transmits transmission data by the UWB communication method. The UWB transmitter 3302 is configured as shown in FIG. 38, for example.

  The UWB receiver 3303 is a receiving device according to the present invention. The data demodulated by the receiving apparatus is sent to the baseband unit 3304 and subjected to baseband processing. Data that has undergone baseband processing is utilized in the application section. The switch 3301 is used for switching transmission / reception signals.

The block diagram for demonstrating 1st Embodiment of the receiver which concerns on this invention. The block diagram for demonstrating the detailed example of the receiver of 1st Embodiment. The flowchart for demonstrating the procedure of the synchronization acquisition in 1st Embodiment. The block diagram for demonstrating the example of the matched filter of 1st Embodiment. The figure for demonstrating operation | movement of the matched filter of 1st Embodiment. The figure for demonstrating each part waveform at the time of achieving the pulse synchronization in the sequential search part of 1st Embodiment. The figure for demonstrating each part waveform when the pulse-synchronization is not achieved in the sequential search part of 1st Embodiment. The figure for demonstrating the effect of shortening of the synchronous acquisition time in 1st Embodiment. The block diagram for demonstrating the example of the timing signal generation part of 1st Embodiment. The block diagram for demonstrating another example of the timing signal generation part of 1st Embodiment. The figure for demonstrating each clock waveform in a timing signal generation part. The block diagram for demonstrating the example of the signal detection and a synchronous control part of 1st Embodiment. The flowchart for demonstrating the example of the synchronization acquisition procedure in 1st Embodiment. The flowchart for demonstrating another example of the synchronization acquisition procedure in a 1st Example. The flowchart for demonstrating another example of the synchronization acquisition procedure in a 1st Example. The block diagram for demonstrating the 2nd Embodiment of this invention. The block diagram for demonstrating the 3rd Embodiment of this invention. The block diagram for demonstrating the detailed example of the receiver of 3rd Embodiment. The block diagram for demonstrating the 4th Embodiment of this invention. The block diagram for demonstrating the 5th Embodiment of this invention. The figure for demonstrating the spreading code length in 5th Embodiment. The block diagram for demonstrating the example of the demodulation part in 5th Embodiment. 10 is a flowchart for explaining an example of a synchronization acquisition procedure in the fifth embodiment. The block diagram for demonstrating another example of the demodulation part in 5th Embodiment. The flowchart for demonstrating another example of the procedure of the synchronization acquisition in 5th Embodiment. The figure for demonstrating the improvement effect of the correlation output in 5th Embodiment. FIG. 10 is a curve diagram for explaining an improvement effect of correlation output in the fifth embodiment. The block diagram for demonstrating the 6th Embodiment of this invention. The block diagram for demonstrating the 7th Embodiment of this invention. The block diagram for demonstrating the example of the variable template pulse generation part in 7th Embodiment. 15 is a flowchart for explaining an example of a synchronization acquisition procedure according to the seventh embodiment. The figure for demonstrating the variable template pulse in 7th Embodiment. The curve figure for demonstrating the effect of 7th Embodiment. The block diagram for demonstrating the 8th Embodiment of this invention. The flowchart for demonstrating the example of the procedure of the synchronization acquisition in 8th Embodiment. The figure for demonstrating the example of the communication apparatus using the receiver of this invention. The figure for demonstrating the waveform of the signal in ultra wide band impulse radio communication. The block diagram for demonstrating the example of a direct spreading | diffusion type UWB-IR transmission apparatus. The block diagram for demonstrating the example of a direct spreading | diffusion type UWB-IR receiver. The figure for demonstrating the time relationship of each waveform at the time of the synchronous acquisition in the receiver of FIG. The figure for demonstrating the pulse waveform after frequency-converting a modulation pulse waveform.

Explanation of symbols

0000 ... Antenna, 0110, 1610, 0210 ... RF front end (RFFE), 0120, 1630, 0220 ... Sequential search unit (SRLSRC), 0130, 1640 ... Code correlation part (CODECORR), 0140, 1650, 0240 ... Signal detection Synchronous control unit (FIND / SYNCCTL), 0150, 1660, 0250 ... Demodulation unit (DEMOD), 1620 ... Frequency conversion unit (FRQCONV), 0221 ... Multiplication unit (MLT), 0222 ... Integration unit or LPF unit (integration filter unit) ) (INT / LPF), 0223 ... Sampling unit (SAMP), 0224 ... Timing signal generation unit (TMSIGG), 0225 ... Template pulse generation unit (TEMPPLSG), 0230 ... Matched filter (MF), 0401 ... Delay circuit, 0402 ... Multiplier circuit, 0403 ... Adder circuit.

Claims (20)

A synchronous detection type receiver that receives a pulse signal spread by a spreading code as a received signal,
A sequential search unit that searches the pulse position of the received signal by a sequential search;
A code correlation unit that obtains a cross-correlation between a search result output output for each pulse period of the pulse signal and the spreading code, and outputs a value of the cross-correlation
A signal detection / synchronization control unit that detects the peak of the cross-correlation value to determine the presence or absence of a received signal, and controls the next search position of the pulse position in the sequential search unit based on the determination result; A receiver characterized by comprising: In claim 1,
The sequential search unit
A template pulse generator for generating a template pulse for pulse synchronization;
A multiplier for multiplying the received signal by the template pulse;
An integration filter unit that integrates the multiplied signal or removes a high-frequency component thereof;
A sampling unit that samples the output signal of the integration filter unit at a predetermined sampling timing and outputs the search result; and
A timing signal generation unit for generating a timing clock for controlling the generation timing of the template pulse, the predetermined sampling timing, and the integration reset timing of the integration filter unit;
The timing of generating the timing clock is controlled by the signal detection / synchronization control unit. In claim 2,
The receiving apparatus according to claim 1, wherein the template pulse is a pulse waveform sequence composed of pulses of the same polarity. In claim 1,
The code correlation unit includes a plurality of delay circuits, a multiplier circuit that multiplies each of the plurality of signals delayed by the plurality of delay circuits and a predetermined coefficient series, and an adder circuit that adds an output signal of the multiplier circuit; A receiving device comprising a matched filter. In claim 1,
The signal detection / synchronization control unit determines the presence or absence of a signal by comparing the peak of the cross-correlation value with a predetermined threshold value. In claim 1,
The sequential search unit
A sampling unit that samples the received signal at a predetermined sampling timing;
A timing signal generator for generating a timing clock for controlling the predetermined sampling timing,
The receiving apparatus, wherein the timing for generating the timing clock is controlled by the detection / synchronization control unit. In claim 2,
The template pulse generation unit generates a plurality of different template pulses to be selected and used. In claim 1,
The receiving apparatus, wherein the received signal is a signal obtained by frequency-converting a carrier wave modulated with a pulse signal spread by the spreading code. In claim 8,
The received signal is composed of an in-phase component and a quadrature component, and the successive search unit is provided for each component,
The code correlation unit obtains the cross-correlation for each component, and the sum of squares of the first cross-correlation obtained for the in-phase component and the second cross-correlation obtained for the quadrature component or An amplitude component obtained by the sum of absolute values is output as the cross-correlation value. In claim 8,
The received signal is composed of an in-phase component and a quadrature component, and the successive search unit is provided for each component,
The code correlation unit obtains the cross-correlation for each component in 1 / m time units of one information unit time, and obtains the first cross-correlation obtained for the in-phase component and the quadrature component. And a second cross-correlation with the sum of squares or the sum of absolute values of the amplitude component obtained n times, and the integration result is output as the cross-correlation value. A transmitter for transmitting a pulse signal spread by a spreading code;
A receiver for synchronous detection that receives the transmitted pulse signal as a received signal;
The receiving device is
A sequential search unit that searches the pulse position of the received signal by a sequential search;
A code correlation unit that obtains a cross-correlation between a search result output output for each pulse period of the pulse signal and the spreading code, and outputs a value of the cross-correlation
A signal detection / synchronization control unit that detects the peak of the cross-correlation value to determine the presence or absence of a received signal, and controls the next search position of the pulse position in the sequential search unit based on the determination result; A communication device characterized by comprising: In claim 11,
The sequential search unit
A template pulse generator for generating a template pulse for pulse synchronization;
A multiplier for multiplying the received signal by the template pulse;
An integration filter unit that integrates the multiplied signal or removes a high-frequency component thereof;
A sampling unit that samples the output signal of the integration filter unit at a predetermined sampling timing and outputs the search result; and
A timing signal generation unit for generating a timing clock for controlling the generation timing of the template pulse, the predetermined sampling timing, and the integration reset timing of the integration filter unit;
The timing for generating the timing clock is controlled by the signal detection / synchronization control unit. In claim 12,
The communication apparatus according to claim 1, wherein the template pulse is a pulse waveform sequence composed of pulses of the same polarity. In claim 11,
The code correlation unit includes a plurality of delay circuits, a multiplier circuit that multiplies each of the plurality of signals delayed by the plurality of delay circuits and a predetermined coefficient series, and an adder circuit that adds an output signal of the multiplier circuit; A communication device comprising: a matched filter. In claim 11,
The signal detection / synchronization control unit determines the presence / absence of a signal by comparing the peak of the cross-correlation value with a predetermined threshold value. In claim 11,
The sequential search unit
A sampling unit that samples the received signal at a predetermined sampling timing;
A timing signal generator for generating a timing clock for controlling the predetermined sampling timing,
The receiving apparatus, wherein the timing for generating the timing clock is controlled by the detection / synchronization control unit. In claim 12,
The template pulse generation unit generates a plurality of different template pulses to be selected and used. In claim 11,
The receiving apparatus, wherein the received signal is a signal obtained by frequency-converting a carrier wave modulated with a pulse signal spread by the spreading code. In claim 18,
The received signal is composed of an in-phase component and a quadrature component, and the successive search unit is provided for each component,
The code correlation unit obtains the cross-correlation for each component, and the sum of squares of the first cross-correlation obtained for the in-phase component and the second cross-correlation obtained for the quadrature component or An amplitude component obtained by the sum of absolute values is output as the cross-correlation value. In claim 18,
The received signal is composed of an in-phase component and a quadrature component, and the successive search unit is provided for each component,
The code correlation unit obtains the cross-correlation for each component in 1 / m time units of one information unit time, and obtains the first cross-correlation obtained for the in-phase component and the quadrature component. And a second cross-correlation with the sum of squares or the sum of absolute values of the amplitude component obtained n times, and the integration result is output as the cross-correlation value.

Images