TW202220395A - Transmission device, reception device, spread spectrum communication system, control circuit, storage medium, transmission method and reception method - Google Patents

Abstract

A transmission device (100) comprises: a spreading process unit (130) that performs a spreading process in which a modulated signal obtained by modulating a transmission bit sequence is multiplied by a spreading sequence; a channel coding unit (140) that performs channel coding on the spreading-processed signal on the basis of the number of transmission antennas; a synchronization chirp signal generation unit (150) that generates a synchronization chirp signal for timing synchronization in a reception device; a time shift unit (160) that generates signals of block units obtained by cyclic-time-shifting the synchronization chirp signal to generate as many known sequences, each consisting of signals of a plurality of blocks, as there are the transmission antennas; and as many waveform shaping/combining units (170-1, 170-2) as there are the transmission antennas, the waveform shaping/combining units being connected to different transmission antennas (180-1, 180-2) and combining a data sequence channel-coded by the channel coding unit (140) with the known sequences to generate and transmit different transmission signals from the transmission antennas (180-1, 180-2).

Description

Transmission device, reception device, spread spectrum communication system, control circuit, memory medium, transmission method and reception method

The present disclosure relates to a transmission device, a reception device, a spread spectrum communication system, a control circuit, a memory medium, a transmission method and a reception method for performing spread spectrum communication.

In the spread spectrum communication, the direct spread method is to use PSK (Phase Shift Keying, phase shift keying), FSK (Frequency Shift Keying, frequency shift keying), etc. to modulate the modulated signal once, and change the chirp sound. The signal, PN (Pseudorandom Noise, Pseudorandom Noise) sequence and other sequences are multiplied as the spread sequence, thereby forming a method of transmitting a signal with a wider frequency bandwidth than the frequency bandwidth of one modulation. In the reception processing, inverse spreading is performed by multiplying a sequence having an inverse characteristic of the spreading sequence, and a modulation signal is extracted. By performing the processing as shown above, the power gain of the long part of the spreading sequence obtained by multiplying the 1 signal of the modulated signal is obtained. Therefore, the direct spreading method is suitable for low SNR (Signal to Noise Ratio, signal-to-noise ratio). It performs long-distance communication of actions. In recent years, LPWA (Low Power Wide Area), which is adopted as a wireless communication method for IoT (Internet of Things) devices, utilizes spread spectrum communication including the above-described direct spreading method.

The chirp signal includes an upward chirp signal whose frequency increases linearly with time, and a downward chirp signal whose frequency decreases linearly with time. In addition, as an example of the aforementioned sequence, there is a ZC (Zadoff-Chu, Zadoff-Zhu) sequence which is one of the CAZAC (Constant Amplitude Zero Auto Correlation) sequences. Since the amplitude of the transmission signal using the sequence shown above has a constant envelope, the power efficiency is high. In addition, the sequence shown above has good correlation characteristics such that the cross-correlation between sequences before and after the tour time shift becomes uncorrelated by performing the tour time shift, so it is generally used as a known sequence in a communication system. Patent Document 1 discloses a technique of using a chirp signal to perform timing synchronization in a receiver in terms of a known sequence in the spread spectrum communication. prior art literature Patent Literature

Patent Document 1: Japanese Patent No. 5699142

[The problem to be solved by the invention]

However, according to the above-mentioned conventional technique, if direct spreading is performed by spread spectrum communication, when the length of the spreading sequence is lengthened by 2 times, 4 times, 8 times, . The problem of increasing the circuit scale for timing synchronization processing. In addition, since the transmitting device achieves diversity gain, multiple antennas are used, and different spreading sequences are used for transmission, so that there is no interference between the signals transmitted by the antennas. Since the synchronization processing of each spreading sequence is performed as the timing synchronization processing, there is a problem that the circuit scale is further increased.

The present disclosure has been made in view of the above-mentioned circumstances, and the purpose is to obtain a timing synchronization process with high accuracy while suppressing an increase in the circuit scale of timing synchronization processing in a receiving device when a signal is transmitted using a plurality of antennas in a spread spectrum communication method. Synchronized messenger. [Means to solve the problem]

In order to solve the above-mentioned problems and achieve the objective, the present disclosure is a transmitter device for wireless communication with a receiver device in a spread spectrum communication system. The transmission device is characterized by comprising: an extension processing part for performing extension processing on a modulated signal whose transmission bit sequence has been modulated by multiplying it by an extension sequence; A transmission path encoding unit for encoding the transmission path by the number of antennas; a synchronization chirp signal generation unit for generating a synchronization chirp signal for timing synchronization in the receiving device; and a region for generating a tour time shift of the synchronization chirp signal block-unit signal, and generate a time-shift part of a known sequence formed by signals of a plurality of blocks with the same number as the number of transmission antennas; The coded data sequence and the known sequence are synthesized to generate different transmission signals, which are transmitted by the above-mentioned transmission antennas. [Effect of invention]

The transmitting device of the present disclosure achieves the effect of accurately performing timing synchronization while suppressing the increase in the circuit scale of timing synchronization processing in the receiving device when using a plurality of antennas to transmit signals in the spread spectrum communication method.

The following will describe in detail the transmission device, the reception device, the spread spectrum communication system, the control circuit, the storage medium, the transmission method and the reception method according to the embodiments of the present disclosure according to the drawings.

Implementation form. FIG. 1 is a diagram showing a configuration example of a spread spectrum communication system 300 according to the present embodiment. The spread spectrum communication system 300 includes a transmission device 100 and a reception device 200 . The spread spectrum communication system 300 shown in FIG. 1 is a schematic diagram simply showing the operations of the transmitter device 100 and the receiver device 200 for wireless communication in the spread spectrum communication method.

The transmission device 100 uses PSK, FSK, etc. to perform a modulation on the transmission bit sequence. The transmitting device 100 uses the chirp signal to directly expand the modulated signal in terms of the spreading sequence, thereby widening the frequency bandwidth of the signal with the length of the spreading sequence. FIG. 1 shows the state of converting the frequency bandwidth of the modulated signal from a narrow frequency band to a wide frequency band by direct expansion. The transmission device 100 transmits an expanded signal with a widened bandwidth.

The receiving device 200 performs timing synchronization on the receiving signal. The receiving device 200 detects the head position of the receiving frame as the expanded signal through timing synchronization, and de-spreads by multiplying the sequence having the inverse characteristic of the spreading sequence used in the transmitting device 100, And extract the signal before expansion. The sequence having an inverse characteristic to the spreading sequence used in the transmission device 100 refers to a sequence in which the phase value is inverted by a composite signal in the case of a constant envelope signal such as a ZC sequence used for a chirp signal. FIG. 1 shows a state in which the frequency bandwidth of the received signal is converted from a wide frequency band to a narrow frequency band by inverse expansion. The received signal in the narrow band corresponds to the signal before expansion in the transmission device 100 . The receiving device 200 performs demodulation processing on the signal before expansion, thereby obtaining the received bit sequence.

1 is a schematic diagram showing the operation of the transmitting device 100 and the receiving device 200 simply, so only the fundamental frequency signal processing is described, and about ADC (Analog to Digital Converters, analog-to-digital converters), DAC (Digital to Analog Converters) , digital-to-analog converter), power amplifier, AGC (Auto Gain Control, automatic gain control) and other actions, the description is omitted. The detailed configuration and operation of the transmitter device 100 and the receiver device 200 using functional blocks will be described later.

FIG. 2 is a first diagram showing an example of a chirp signal used in the spread spectrum communication system 300 of the present embodiment. FIG. 3 is a second diagram showing an example of a chirp signal used in the spread spectrum communication system 300 of the present embodiment. In FIGS. 2 and 3 , the horizontal axis represents time, and the vertical axis represents frequency. FIG. 2 shows the time and frequency characteristics of the upper chirp signal as the chirp signal. As shown in Figure 2, the upper chirp signal is a chirp signal whose frequency increases linearly with time. FIG. 3 shows the time and frequency characteristics of the down-chirp signal as the chirp signal. As shown in FIG. 3 , the lower chirp signal is a chirp signal whose frequency decreases linearly with time. As an example, the upper chirp signal is used for illustration, but either one of the upper chirp signal and the lower chirp signal or a combination of the two signals can be used as a known sequence.

Next, in the present embodiment, a known sequence that is known between the sender apparatus 100 and the receiver apparatus 200 and used when the receiver apparatus 200 performs timing synchronization will be described. Here, an example is described in which the transmission device 100 is provided with two transmission antennas, and the transmission signal is transmitted by the two transmission antennas. FIG. 4 is a diagram showing an example of a known sequence used for a transmission signal transmitted from the first transmission antenna of the transmission apparatus 100 of the present embodiment. FIG. 5 is a diagram showing an example of a known sequence used for a transmission signal transmitted from the second transmission antenna of the transmission apparatus 100 of the present embodiment. In FIGS. 4 and 5 , the horizontal axis represents time, and the vertical axis represents frequency. The chirp signals shown in FIG. 4 and FIG. 5 correspond to the hour slot of 1 grid on the horizontal axis in the figure, and correspond to the upward chirp signal with a frequency increase of 1 grid on the vertical axis in the graph.

In this embodiment, as shown in FIGS. 4 and 5 , a 5-hour slot is used as one block, and two blocks are used as a known sequence. In the known sequence used by the first transmission antenna shown in FIG. 4, block #1 is set as the sequence increasing in order from frequency (1), and block #2 is set as the sequence from frequency (4) Incremental sequence. However, in the present embodiment, since frequencies (1) to (4) are assumed to be the channel bandwidths, the next steps of frequency (4) are processed so as to be cyclically shifted to frequency (1). That is, if the sequence of the block #1 is used as a reference, the sequence of the block #2 is a sequence that is time-shifted in the negative direction for one frequency share. The known sequence used in the second transmission antenna shown in FIG. 5 is set as a sequence in which the sequence order of block #1 and block #2 is changed with respect to the known sequence used in the first transmission antenna.

Among them, the frequency components described by the dotted lines in FIG. 4 and FIG. 5 are actually transmitted signal components, but are omitted in the following description. These frequency components are components that are not detected in the process of timing synchronization of the receiving device 200 to be described later. In FIGS. 4 and 5 , since the length of the spreading sequence of each block is 1/5, the portion of the dotted line occupies 1/5. Therefore, if it is not detected, the power loss will appear to be large. However, if the extension sequence length is increased for long-distance communication, for example, if the number of time slots and frequency components is increased to 1024, the proportion of the dotted line part is very small, which is 1/1025. In terms of the amount of reduction in synchronization accuracy, it can be said to be a small amount.

The configuration and operation of the transmission device 100 will be described in detail. FIG. 6 is a block diagram showing a configuration example of the transmission device 100 of the present embodiment. The transmission device 100 includes a modulation unit 110, a chirp signal generating unit 120, an extension processing unit 130, a transmission path coding unit 140, a synchronizing chirp signal generating unit 150, a time shifting unit 160, a waveform shaping unit 170- 1. 170-2, and transmission antennas 180-1 and 180-2. The sending antenna 180-1 corresponds to the aforementioned first sending antenna, and the sending antenna 180-2 corresponds to the aforementioned second sending antenna. In the following description, if the waveform shaping and synthesizing sections 170-1 and 170-2 are not distinguished, it will be referred to as the waveform shaping and synthesizing section 170, and if the transmission antennas 180-1 and 180-2 are not distinguished, it will be referred to as the “transmitting antenna”. the case of the communication antenna 180 . FIG. 7 is a flowchart showing the operation of the transmission device 100 of the present embodiment.

The modulation unit 110 performs a modulation on the transmission bit sequence using PSK, FSK, etc. (step S101 ). The modulation unit 110 performs processing equivalent to "one-shot modulation" in FIG. 1 .

The chirp signal generating unit 120 generates a chirp signal for expansion processing (step S102 ). Here, the spread sequence is set as a chirp signal, but in this embodiment, if the known sequence is a chirp signal, the chirp signal generating unit 120 can also generate other spread sequences.

The expansion processing unit 130 multiplies the chirp signal generated by the chirp signal generating unit 120 on the modulation signal that has been modulated once in the modulation unit 110 , thereby performing direct expansion, that is, expansion processing (step S103 ). . The chirp signal generation unit 120 and the extension processing unit 130 perform processing equivalent to "direct extension" in FIG. 1 .

The transmission path coding unit 140 transmits the expanded signal subjected to the expansion processing by the expansion processing unit 130 by the two transmission antennas 180-1 and 180-2, and therefore, according to the number of the transmission antennas 180, a transmission path is performed. encoding (step S104). In terms of transmission channel coding, it is sufficient if the transmission signals transmitted by the two transmission antennas 180-1 and 180-2 do not interfere with each other, or Alamouti STBC (Space Time Block Coding, If it is a chirp signal, it can also be used to perform frequency shift processing on one of the signals and the other on the other. The transmission channel encoding unit 140 outputs the data sequence belonging to the signal encoded by the transmission channel to the waveform shaping and synthesizing units 170-1 and 170-2.

The synchronization chirp signal generation unit 150 generates a chirp signal for timing synchronization in the reception device 200 (step S105 ). Specifically, the chirp signal generator 150 for synchronization generates the signal of block #1 in the known sequence for the transmission antenna 180-1 shown in FIG. 4 .

The time shift unit 160 obtains the signal of the block #1 for the transmission antenna 180-1 from the synchronization chirp signal generation unit 150, and performs time shift on the signal of the block #1 for the transmission antenna 180-1, And the signal of block #2 for the transmission antenna 180-1 is generated. The time shift unit 160 uses the acquired signal of the block #1 for the transmission antenna 180-1 and the generated signal of the block #2 for the transmission antenna 180-1 to generate the signal shown in FIG. 4 . The known sequence for the transmission antenna 180-1 and the known sequence for the transmission antenna 180-2 shown in FIG. That is, the time shift unit 160 generates a block-by-block signal obtained by time-shifting the chirp signal for synchronization, and generates a known sequence of signals of plural blocks equal to the number of the transmitting antennas 180 . (step S106). The time shift amount in the time shift unit 160 may also be zero for some blocks. The time shift unit 160 outputs the known sequence for the transmission antenna 180-1 to the waveform shaping and synthesis unit 170-1, and outputs the known sequence for the transmission antenna 180-2 to the waveform shaping and synthesis unit 170-2.

The waveform shaping and synthesizing unit 170-1 converts the data sequence acquired by the transmission path coding unit 140 and the known sequence for the transmission antenna 180-1 acquired by the time shifting unit 160 into, for example, a known sequence or a data sequence. synthesized in a sequential manner. The waveform shaping and synthesizing unit 170-1 transmits the framing signal as the first transmission signal from the transmission antenna 180-1. Similarly, the waveform shaping and synthesizing unit 170-2 converts the data sequence acquired by the transmission path coding unit 140 and the known sequence acquired by the time shifting unit 160 for the transmission antenna 180-2 into, for example, a known sequence , the sequence of the data sequence is synthesized. The waveform shaping and synthesizing unit 170-2 transmits the synthesized and positioned signal as the second transmission signal by the transmission antenna 180-2. As described above, the waveform shaping and synthesizing units 170 - 1 and 170 - 2 are connected to different transmission antennas 180 respectively, and combine the data sequence encoded by the transmission channel in the transmission channel encoding unit 140 with the data sequence generated by the time shifting unit 160 . The known sequences are synthesized to generate different transmission signals, which are transmitted by the transmission antenna 180 (step S107 ). The number of the waveform shaping and synthesizing sections 170 is the same as the number of the transmitting antennas 180 .

FIG. 8 is a diagram showing an example of a frame of each transmission signal generated and transmitted by the transmission apparatus 100 of the present embodiment. In FIG. 8, the horizontal axis represents time. Among them, in the example of FIG. 8 , the known sequence is provided at the head of the transmission signal, which is only an example, and is not limited to this. The waveform shaping and synthesizing unit 170 may also be provided at positions other than the head of the transmission signal for the known sequence.

In the present embodiment, the number of the transmission antennas 180 included in the transmission device 100 is two or more. The transmission signal transmitted by each transmission antenna 180 of the transmission device 100 includes known sequences with different tour time shift amounts of the chirp signal for synchronization. The known sequence is constituted by the number of blocks more than the number of the transmission antennas 180 , and in the same block position, the tour time shift amount of the chirp signal for synchronization depends on the number of transmissions transmitted by each of the transmission antennas 180 . Signals vary. In the known sequence, the number of candidates for the tour time shift amount obtained by accumulating the tour time shift amount in the entire block is the same in each transmission signal.

Next, the reception processing of the reception device 200 will be described. FIG. 9 is a diagram showing an example of a known sequence portion of a composite signal received by the receiving device 200 when the transmitting device 100 of the present embodiment uses two transmitting antennas 180-1 and 180-2 to transmit the outgoing signal. . In FIG. 9 , the horizontal axis represents time, and the vertical axis represents frequency. In addition, in FIG. 9, the black line represents the known sequence of the signal transmitted and received by the transmission antenna 180-1, and the white line represents the known sequence of the signal transmitted and received by the transmission antenna 180-2. FIG. 10 is a diagram showing an example of a known sequence for correlation processing generated for detecting the start position of the chirp signal for synchronization with respect to the synthesized signal in the receiving apparatus 200 of the present embodiment. The receiving apparatus 200 may generate a sequence of 1 block in a known sequence consisting of 2 blocks. The known sequence generated by the receiving device 200 corresponds to the part except the dotted line in each block of the known sequence shown in FIGS. 4 and 5 .

11 is a diagram showing a schematic diagram of the output when the receiving apparatus 200 of the present embodiment receives the composite signal shown in FIG. 9 and calculates the correlation value by performing cross-correlation using the known sequence for correlation processing shown in FIG. 10 . FIG. 11( a ) is the same as the aforementioned FIG. 9 . In FIG. 11( b ), the horizontal axis represents time, and the vertical axis represents the correlation value. When the receiving apparatus 200 performs cross-correlation using the known sequence for correlation processing shown in FIG. 10 , peaks of correlation values appear for components that increase in time slots of 1 hour each at frequencies (1) to (4). , so the peaks of the correlation values are obtained at the beginning of time (1), time (2), time (6), and time (7), respectively. Usually, the propagation loss between the transmitting antenna 180-1 and the receiving antenna of the receiving device 200 and the propagation loss between the transmitting antenna 180-2 and the receiving antenna of the receiving device 200 have different values. , but in the example of Figure 11 is treated as the same propagation loss. The receiving apparatus 200, after detecting the peak of the correlation value, synthesizes the peaks of the correlation value as described later.

Among them, in the present embodiment, it is formed as a known sequence consisting of only the above chirp signals, but if the signal combining the up chirp signal and the down chirp signal is used as a known sequence, the receiving device 200 will The respective sequences of the upper chirp signal and the lower chirp signal are individually correlated, and thus the respective obtained correlation values are synthesized. In this case, in order to make the reception device 200 the same circuit scale as that of the present embodiment, it is necessary to form each sequence of the upper chirp signal and the lower chirp signal into 2-hour time slots, so as to form a total of 4-hour time slots long known sequences.

FIG. 12 is a schematic diagram showing the combination of the peaks of the correlation values calculated in FIG. 11 by the receiving apparatus 200 of the present embodiment. In each graph of FIG. 12 , the horizontal axis represents time, and the vertical axis represents correlation values. Fig. 12(a) is the same as the aforementioned Fig. 11(b). The receiving apparatus 200 first performs inter-block synthesis on the output of the correlation processing, and obtains the power sum of the correlation value one block time ago. Thereby, the correlation value characteristic of Fig. 12(b) is obtained. The receiving device 200 then performs intra-block synthesis on the correlation value characteristic of FIG. 12( b ), and in the part where the transmitting device 100 performs time shifting, in this embodiment, specifically, a time slot corresponding to only 1 hour is obtained. The power sum of the previous correlation values. Thereby, the correlation value characteristic of FIG. 12( c ) is obtained. After performing the above processing, the receiving device 200 identifies the position of the known sequence by detecting the peak of the final correlation value characteristic.

In the example of Fig. 12, the peak of the correlation value is obtained at the head of time (2) in the known sequence, so it can be seen that the position before the slot when the peak position is 1 hour is the head position of the known sequence. According to the characteristics of the detection method of the correlation value peak of the receiving device 200 of the present embodiment, even in the case where the transmission signal of one of the transmitting antennas 180 of the transmitting device 100 cannot be obtained, only as shown in FIG. 12 . Either the black line or the white line can not be obtained as a correlation value, and the correlation value peak is obtained at the same position for the transmission signal of the other transmission antenna 180 of the transmission device 100 . Therefore, the receiving device 200 has nothing to do with the state of the wireless transmission path between the transmitting device 100 and the receiving device 200 . If the signal transmitted by any of the transmitting antennas 180 is in a receivable state, timing synchronization can be performed. In addition, the above-mentioned feature is that even if the number of transmitting antennas 180 of the transmitting device 100 is one, it can be said that the same timing synchronization method can be applied to the receiving device 200 .

The configuration and operation of the receiving device 200 will be described in detail. FIG. 13 is a block diagram showing a configuration example of the receiving apparatus 200 of the present embodiment. The receiving apparatus 200 includes a receiving antenna 210 , a band limiting unit 220 , a timing synchronization unit 230 , a despreading processing unit 240 , and a demodulating unit 250 . FIG. 14 is a flowchart showing the operation of the receiving apparatus 200 of the present embodiment.

The band-limiting unit 220 performs band-limiting on the received signal received by the receiving antenna 210 by using a band-limiting filter (step S201 ). The frequency band limiting unit 220 extracts only the signal of the desired frequency band, that is, the information of the received channel by the frequency band limitation.

The timing synchronization unit 230 performs timing synchronization using the information of the reception channel extracted by the band limiting unit 220, and detects the head position of the reception frame included in the reception signal (step S202). The sequence synchronization unit 230 performs processing corresponding to "sequence synchronization" in FIG. 1 .

The configuration and operation of the timing synchronization unit 230 will be described in detail. FIG. 15 is a block diagram showing an example of the configuration of the timing synchronization unit 230 included in the reception device 200 of the present embodiment. The timing synchronization unit 230 includes a correlation sequence generation unit 231 , a correlation processing unit 232 , an inter-block synthesis unit 233 , an intra-block synthesis unit 234 , and a spike detection unit 235 . FIG. 16 is a flowchart showing the operation of the timing synchronization unit 230 included in the reception device 200 of the present embodiment. In the sequence synchronization unit 230, the correlation sequence generation unit 231 generates a known sequence for the correlation processing shown in FIG. 10 (step S301). The known sequence for correlation processing includes all or part of the synchronization chirp signal for timing synchronization generated by the synchronization chirp signal generator 150 of the transmission device 100 .

The correlation processing unit 232 performs correlation processing between the signal of the desired frequency band extracted by the band limiting unit 220 and the known sequence for correlation processing generated by the correlation sequence generating unit 231 (step S302 ). By the correlation processing of the correlation processing unit 232 , the peak of the correlation value as shown in FIG. 12( a ) is obtained.

The inter-block combining unit 233 performs inter-block combining on the output from the correlation processing unit 232 (step S303 ), and combines the powers of all the blocks in the known sequence. Through the inter-block synthesis process of the inter-block synthesis unit 233, a correlation value peak as shown in FIG. 12(b) is obtained.

The intra-block synthesizing unit 234 performs intra-block synthesizing on the output from the inter-block synthesizing unit 233 (step S304 ), and synthesizes the correlation value of the time shift added by the transmission device 100 . Through the intra-block synthesis process of the intra-block synthesis unit 234, a correlation value peak as shown in FIG. 12( c ) is obtained.

The peak detection unit 235 detects the correlation peak from the output from the intra-block synthesis unit 234, ie, the correlation peak as shown in FIG. 12( c ), to specify the head position of the received frame (step S305 ). The spike detection unit 235 outputs position information specifying the head position of the received frame as a result of timing synchronization.

As described above, the timing synchronization unit 230 generates a known sequence for correlation processing including all or a part of the synchronization chirp signal for timing synchronization generated by the transmission device 100, and performs correlation between the signal of a desired frequency band and the The correlation value obtained by the correlation processing of the known sequence is processed, the peak of the correlation value is detected, and the timing synchronization of the head position of the received frame included in the specific received signal is performed. The timing synchronization unit 230 synthesizes the peak value obtained by the correlation processing between blocks of a known sequence consisting of signals of a plurality of blocks with different voyage time shift amounts, and also performs the peak value after synthesizing within the block. detection, thereby performing timing synchronization.

Return to the description of FIGS. 13 and 14 . The de-spreading processing unit 240 specifies the position of the receiving frame by using the signal of the desired frequency band extracted by the band limiting unit 220 and using the position information obtained by the timing synchronization unit 230, and will have the corresponding position of the receiving frame. The sequence of the inverse characteristic of the spreading sequence used by the apparatus 100 is multiplied to perform inverse spreading (step S203 ). The de-spreading processing unit 240 extracts the signal before the expansion of the transmission device 100 by de-spreading. The de-spreading processing unit 240 performs processing corresponding to "de-spreading" in FIG. 1 .

The demodulation unit 250 extracts a data sequence from the signal before expansion, and performs demodulation processing (step S204). The demodulation unit 250 obtains the received bit sequence through demodulation processing. The demodulation unit 250 performs processing corresponding to "demodulation" in FIG. 1 .

As shown above, in the spread spectrum communication system 300, even when the transmitting device 100 uses the plurality of transmitting antennas 180 for transmitting, the receiving device 200 can perform the timing synchronization as described above to simplify the The processing accuracy is good for timing synchronization.

In this embodiment, the case where the number of the transmission antennas 180 of the transmission device 100 is two is described, but it is only an example, and it can also be applied to the case where the number of the transmission antennas 180 of the transmission device 100 is three. situation. Specifically, with regard to the known sequence for timing synchronization, each time the number of the transmission antennas 180 of the transmission device 100 increases by one, that is, one or more time-shifted candidates are added in each block, and the number of additional blocks constituted Also increased by 1 or more.

FIG. 17 is a diagram showing a known sequence portion of a composite signal received by the receiving device 200 when the transmitting device 100 according to the present embodiment uses the three transmitting antennas 180 to transmit the transmitting signal. FIG. 18 is a schematic diagram showing that the receiving apparatus 200 synthesizes the peaks of the correlation values when the transmitting apparatus 100 of the present embodiment uses the three transmitting antennas 180 to transmit the transmitting signal. 19 is a diagram showing a known sequence portion of a composite signal received by the receiving device 200 when the transmitting device 100 of the present embodiment uses four transmitting antennas 180 to transmit the transmitting signal. FIG. 20 is a schematic diagram showing that the receiving apparatus 200 synthesizes the peaks of the correlation values when the transmitting apparatus 100 of the present embodiment uses the four transmitting antennas 180 to transmit the transmitting signal. In FIGS. 17 to 20 , the black line indicates the signal corresponding to the signal transmitted by the first transmission antenna of the transmission device 100 , and the white line indicates the signal corresponding to the signal transmitted by the second transmission antenna of the transmission device 100 . The signal corresponding to the transmitted signal is represented by a dotted line, the signal corresponding to the signal transmitted by the third transmission antenna of the transmission device 100 . In addition, in FIG. 19 and FIG. 20, the signal corresponding to the signal transmitted from the 4th transmission antenna of the transmission apparatus 100 is shown by the three-layered line.

Regarding the correlation value spikes in FIGS. 18 and 20 , in the receiving device 200, only the block whose inter-block synthesis and intra-block synthesis are performed to obtain the largest peak value is described, and the notation of the correlation value of the adjacent blocks is omitted. . In terms of the structure of the known sequence contained in the transmission signal transmitted by each transmission antenna 180 of the transmission device 100, for example, if the number of the transmission antennas 180 is 3, the black line in block #1 The time shift amount of , is set to 0, the time shift amount of the white line is set to 1, and the time shift amount of the dotted line is set to 2. If the time shift amount of 3 blocks is arranged numerically, such as 0.1.2, 1.2.0, 2.0.1, the transmission device 100 makes the time shift amount circularly shifted for each block, In this way, timing synchronization can be performed on the receiving device 200 . The receiving device 200 performs correlation processing on the received signal using the same known sequence for correlation processing as when the number of the transmitting antennas 180 is 2, and then performs inter-block synthesis of three blocks, and finally combines the two signals. The correlation value characteristic shown in FIG. 18 is obtained by synthesizing the peak values corresponding to the time shift amounts 0, 1, and 2 within the block. Even if the number of the transmission antennas 180 of the transmission device 100 is 4, compared to the case where the number of the transmission antennas 180 is 3, if the number of blocks of a known sequence is increased by 1, the number of each block is also increased by 1. The candidate for the time shift amount of the block can be used accordingly.

From the above description, if the pattern generation method for a known sequence is generalized, the following three generation conditions are satisfied. The first is to form a known sequence with the number of blocks equal to or greater than the number of the transmission antennas 180 of the transmission device 100, and to form a candidate for the time shift amount of each block, and to install the transmission antennas 180 of the transmission device 100. quantity or more. The second is an arrangement of known signals in each block, and is set to different time shift amounts so that the signals of the respective transmission antennas 180 of the transmission device 100 do not interfere with each other. The third is for the known sequence for each transmission antenna 180 of the transmission device 100, and each time shift amount candidate is used the same number of times as a total of all blocks constituting the known sequence.

Next, the hardware configuration of the transmission device 100 will be described. In the transmission device 100, the transmission antenna 180 is realized by an antenna element. The modulation unit 110, the chirp signal generating unit 120, the extension processing unit 130, the transmission path coding unit 140, the chirp signal generating unit 150 for synchronization, the time shifting unit 160, and the waveform shaping unit 170 are realized by processing circuits . The processing circuit may also be a processor and memory that executes programs stored in the memory, or may be dedicated hardware. The processing circuit is also referred to as the control circuit.

FIG. 21 is a diagram showing an example of the configuration of the processing circuit 90 when the processor 91 and the memory 92 realize the processing circuit included in the transmission device 100 of the present embodiment. The processing circuit 90 shown in FIG. 21 is a control circuit, and includes a processor 91 and a memory 92 . If the processing circuit 90 is composed of the processor 91 and the memory 92, each function of the processing circuit 90 is realized by software, firmware, or a combination of software and firmware. Software or firmware is described as programs and stored in memory 92 . In the processing circuit 90, the processor 91 reads out and executes the program stored in the memory 92, thereby realizing each function. That is, the processing circuit 90 is provided with the memory 92 for storing a program for executing the processing of the transmission device 100 on the result. The program can also be described as a program for causing the transmission device 100 to execute each function realized by the processing circuit 90 . The program can be provided by a memory medium in which the program is stored, or provided by other means such as a communication medium.

The above program can also be described as a program for causing the transmission device 100 to execute the following steps: the first step of the extension processing by the extension processing unit 130 by multiplying the modulation signal modulated by the transmission bit sequence by the extension sequence; the transmission path coding unit 140. The second step of encoding the transmission channel according to the number of transmitting antennas for the signal that has been expanded and processed by the expansion processing unit 130; The third step of the signal: the time shift unit 160 generates a signal of the block unit after shifting the chirp signal for synchronization by the tour time, and generates a known signal composed of a plurality of blocks with the same number as the number of transmitting antennas. The fourth step of the sequence; and each of the waveform shaping and synthesizing sections 170 having the same number as the number of transmission antennas is connected to a different transmission antenna 180, and the data sequence encoded by the transmission channel in the transmission channel encoding section 140 is compared with the known sequence. The fifth step is to synthesize and generate different transmission signals to be transmitted by the transmission antenna 180 .

Here, the processor 91 is, for example, a CPU (Central Processing Unit, central processing unit), a processing device, an arithmetic device, a microprocessor, a microcomputer, or a DSP (Digital Signal Processor, digital signal processor). In addition, the memory 92 is, for example, RAM (Random Access Memory), ROM (Read Only Memory), flash memory, and EPROM (Erasable Programmable ROM). read memory), EEPROM (registered trademark) (Electrically EPROM, electronically erasable programmable read-only memory) and other non-volatile or volatile semiconductor memories, magnetic disks, floppy disks, optical disks, CDs, mini disks , or DVD (Digital Versatile Disc, digital video disc), etc. are suitable.

FIG. 22 is a diagram showing an example of the processing circuit 93 when the processing circuit included in the transmission device 100 of the present embodiment is constituted by dedicated hardware. The processing circuit 93 shown in FIG. 22 is composed of, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field- Programmable Gate Array, field programmable gate array) or a combination of these are suitable. With regard to the processing circuit, a part of the processing circuit can also be implemented by dedicated hardware, and a part can also be implemented by software or firmware. As shown above, the processing circuit can implement the above-mentioned functions through dedicated hardware, software, firmware, or a combination thereof.

Among them, the receiving device 200 is also realized by the same hardware configuration as that of the transmitting device 100 . In the receiving device 200, the receiving antenna 210 is an antenna element. The band limiting unit 220, the timing synchronization unit 230, the despreading processing unit 240, and the demodulating unit 250 are realized by processing circuits. The processing circuit may be a processor and memory for executing the program stored in the memory, or may be dedicated hardware.

As described above, according to the present embodiment, in the spread spectrum communication system 300, the transmission device 100 divides and shortens the known sequence for obtaining the desired power gain, that is, the division unit, that is, the block is formed as The transmission process is performed after applying the tour time shift in block units. The receiving apparatus 200 performs cross-correlation processing on the known sequence before the tour time shift of each block, and synthesizes the complex correlation value peak obtained as a result of the processing in consideration of the tour time shift. There is correlation processing of block length, and timing synchronization is performed with good accuracy. Therefore, if the transmission device 200 adopts the spread spectrum communication method, when the transmission device 100 uses the plurality of transmission antennas 180 to transmit signals, the timing synchronization can be performed with high accuracy while suppressing the increase in the circuit scale of the timing synchronization process. .

The configuration shown in the above embodiment is an example, and may be combined with other well-known techniques, the embodiments may be combined with each other, and a part of the configuration may be omitted or changed within a range that does not deviate from the gist.

90: Processing circuit 91: Processor 92: memory 93: Processing circuit 100: Sending device 110: Modulation Department 120: Chirp signal generator 130: Extended Processing Department 140: Transmission path coding section 150: Chirp signal generator for synchronization 160: Time shift part 170-1, 170-2: Wave Shaping and Synthesizing Section 180-1, 180-2: Transmission antenna 200: Receiver 210: Receiver antenna 220: Band Limiting Section 230: Timing Synchronization Department 231: Correlation sequence generation section 232: Relevant Processing Department 233: Interblock Synthesis Department 234: Intra-block Synthesis Department 235: Spike detection section 240: Inverse expansion processing section 250: Demodulation Department 300: Spread Spectrum Communication Systems

[FIG. 1] A diagram showing a configuration example of a spread spectrum communication system according to the present embodiment [Fig. 2] Fig. 1 is a first diagram showing an example of a chirp signal used in the spread spectrum communication system of the present embodiment Fig. 3 is a second diagram showing an example of a chirp signal used in the spread spectrum communication system of the present embodiment [ Fig. 4 ] A diagram showing an example of a known sequence used in a transmission signal transmitted from the first transmission antenna of the transmission device of the present embodiment [ Fig. 5] Fig. 5 is a diagram showing an example of a known sequence used in a transmission signal transmitted from the second transmission antenna of the transmission device of the present embodiment Fig. 6 is a block diagram showing a configuration example of the transmission device of the present embodiment Fig. 7 is a flowchart showing the operation of the transmission device of the present embodiment Fig. 8 is a diagram showing an example of a frame of each transmission signal generated and transmitted by the transmission device of the present embodiment Fig. 9 is a diagram showing an example of a known sequence portion of a composite signal received by the receiving device when the transmitting device according to the present embodiment transmits the outgoing signal by using two transmitting antennas Fig. 10 is a diagram showing an example of a known sequence for correlation processing that is generated for detecting the start position of the chirp signal for synchronization with the synthesized signal in the receiving apparatus of the present embodiment [Fig. 11] Fig. 11 is a diagram showing a schematic diagram of the output when the receiver of the present embodiment receives the composite signal shown in Fig. 9 and uses the known sequence for correlation processing shown in Fig. 10 to perform cross-correlation to calculate a correlation value. [ Fig. 12 ] A diagram showing a schematic diagram of how the receiving apparatus according to the present embodiment will synthesize the peaks of the correlation values calculated in Fig. 11 . Fig. 13 is a block diagram showing an example of the configuration of the reception device according to the present embodiment Fig. 14 is a flowchart showing the operation of the reception device of the present embodiment Fig. 15 is a block diagram showing an example of the configuration of the timing synchronization unit included in the reception device according to the present embodiment Fig. 16 is a flowchart showing the operation of the timing synchronization unit included in the receiving device according to the present embodiment Fig. 17 is a diagram showing the known sequence portion of the composite signal received by the receiving device when the transmitting device according to the present embodiment uses three transmitting antennas to transmit the outgoing signal [ Fig. 18 ] is a schematic diagram showing that the receiving device synthesizes the peaks of correlation values when the transmitting device according to the present embodiment transmits the outgoing signal by using three transmitting antennas Fig. 19 is a diagram showing the known sequence part of the composite signal received by the receiving device when the transmitting device according to the present embodiment uses four transmitting antennas to transmit the outgoing signal Fig. 20 is a schematic diagram showing that the receiving device synthesizes the peaks of correlation values when the transmitting device according to the present embodiment transmits the outgoing signal by using four transmitting antennas 21 is a diagram showing an example of the configuration of a processing circuit when the processing circuit included in the transmission device of the present embodiment is realized by a processor and a memory [ Fig. 22 ] A diagram showing an example of a processing circuit when the processing circuit included in the transmission device of the present embodiment is constituted by dedicated hardware

100: Sending device

110: Modulation Department

120: Chirp signal generator

130: Extended Processing Department

140: Transmission path coding section

150: Chirp signal generator for synchronization

160: Time shift part

170-1, 170-2: Wave Shaping and Synthesizing Section

180-1, 180-2: Transmission antenna

Claims (12)

A transmission device, which is a transmission device for wireless communication with a reception device in a spread spectrum communication system, is characterized by: have: an extension processing unit for performing extension processing on the modulation signal modulated by the transmitted bit sequence by multiplying the extension sequence; A transmission path coding section that performs transmission path coding according to the number of transmission antennas for the signal that has been expanded and processed by the expansion processing section; a synchronization chirp signal generator for generating a synchronization chirp signal for timing synchronization in the receiving device; generating a block-by-block signal by shifting the chirp signal for synchronization by the tour time, and generating a time-shifted portion of a known sequence of signals of a plurality of blocks with the same number as the number of transmitting antennas; and Each is connected to a different transmission antenna, and the data sequence encoded by the transmission path in the transmission path encoding section is synthesized with the known sequence to generate a different transmission signal, which is transmitted by the transmission antenna. A waveform shaping and synthesis section with the same number of signal antennas. The transmission device of claim 1, wherein the number of said transmission antennas is 2 or more, The transmission signal transmitted from each transmission antenna includes the known sequence in which the chirp signal for synchronization is different from each other in the travel time shift amount. The transmission device of claim 2, wherein the known sequence is constituted by the number of blocks more than the number of transmission antennas, and at the same block position, the tour time shift amount of the chirp signal for synchronization is determined by The transmission signals transmitted by the transmission antennas are different, and the number of candidates for the tour time shift amount obtained by accumulating the tour time shift amount in the entire block is the same for each transmission signal. A receiving device, which is a receiving device for wireless communication with a transmitting device in a spread spectrum communication system, is characterized by: have: A band-limiting unit that performs band-limiting on the signal transmitted and received by the aforementioned transmission device, that is, the received signal, and extracts the signal of the desired band; and Generating a known sequence for correlation processing including all or a part of the chirp signal for timing synchronization generated by the transmission device, and performing correlation between the signal of the desired frequency band and the known sequence for correlation processing The obtained correlation value is processed, the peak of the correlation value is detected, and a timing synchronization unit that performs timing synchronization for specifying the head position of the received frame included in the aforementioned received signal. The receiving apparatus of claim 4, wherein the timing synchronization unit performs the processing of the peak value obtained by the correlation processing between the blocks of the known sequence formed by the signals of the plural blocks with different circling time shifts. Synthesizing, and additionally performing a spike detection after synthesizing within a block, thereby performing timing synchronization. A spread spectrum communication system is characterized by: have: if the transmission device of any one of claims 1 to 3; and Such as the receiving device of claim 4 or 5. A control circuit, which is used to control a transmission device that performs wireless communication with a reception device in a spread spectrum communication system, is characterized by: Make the aforementioned messenger implement: The spreading processing of multiplying the spreading sequence of the modulated modulated signal of the transmitted bit sequence; For the expanded signal, the transmission channel coding is performed according to the number of transmission antennas; generating a synchronization chirp signal for timing synchronization in the aforementioned receiving device; generating the signal of the block unit after shifting the chirp signal for synchronization by the tour time, and generating a known sequence formed by the signal of a plurality of blocks with the same number as the number of the aforesaid transmitting antennas; The data sequence encoded by the transmission path and the aforementioned known sequence are synthesized to generate different transmission signals, which are transmitted by the transmission antenna. A control circuit, which is used to control a control circuit of a receiving device that performs wireless communication with a transmitting device in a spread spectrum communication system, is characterized by: Make the aforementioned receiver implement: Band limitation is performed on the signal transmitted and received by the aforementioned sending device, that is, the received signal, and the signal of the desired frequency band is extracted; Generating a known sequence for correlation processing including all or a part of the chirp signal for timing synchronization generated by the transmission device, and performing correlation between the signal of the desired frequency band and the known sequence for correlation processing The obtained correlation value is processed, the peak of the correlation value is detected, and the timing synchronization of the position of the head of the receiving frame included in the receiving signal is specified. A memory medium, which is a memory medium with a program for controlling a transmitting device that performs wireless communication with a receiving device in a spread spectrum communication system, is characterized by: The aforementioned program causes the aforementioned signaling device to implement: The spreading processing of multiplying the spreading sequence of the modulated modulated signal of the transmitted bit sequence; For the expanded signal, the transmission channel coding is performed according to the number of transmission antennas; generating a synchronization chirp signal for timing synchronization in the aforementioned receiving device; generating the signal of the block unit after shifting the chirp signal for synchronization by the tour time, and generating a known sequence formed by the signal of a plurality of blocks with the same number as the number of the aforesaid transmitting antennas; The data sequence encoded by the transmission path and the aforementioned known sequence are synthesized to generate different transmission signals, which are transmitted by the transmission antenna. A memory medium, which is a memory medium with a program for controlling a receiving device that performs wireless communication with a transmitting device in a spread spectrum communication system, is characterized by: The aforementioned program causes the aforementioned receiving device to implement: Band limitation is performed on the signal transmitted and received by the aforementioned sending device, that is, the received signal, and the signal of the desired frequency band is extracted; Generating a known sequence for correlation processing including all or a part of the chirp signal for timing synchronization generated by the transmission device, and performing correlation between the signal of the desired frequency band and the known sequence for correlation processing The obtained correlation value is processed, the peak of the correlation value is detected, and the timing synchronization of the position of the head of the receiving frame included in the receiving signal is specified. A method for sending a message, which is a method for sending a message of a sending device that performs wireless communication with a receiving device in a spread spectrum communication system, and is characterized by: Include: The extension processing part multiplies the modulation signal modulated by the transmission bit sequence by the extension sequence to perform the first step of extension processing; The transmission path coding part performs the second step of coding the transmission path according to the number of transmission antennas for the signal that has been expanded and processed by the expansion processing part; The third step of generating a chirp signal for synchronization for generating a chirp signal for timing synchronization in the aforementioned receiving device; The time shift unit generates a signal in units of blocks by shifting the chirp signal for synchronization by the tour time, and generates a known sequence of signals of a plurality of blocks with the same number as the number of transmission antennas. ;and Each of the waveform shaping and synthesizing units having the same number as the number of transmission antennas is connected to different transmission antennas, and the data sequence encoded by the transmission channel in the transmission channel encoding unit is synthesized with the known sequence to generate different transmission signals. The fifth step of transmitting the signal by the transmitting antenna. A receiving method, which is a receiving method of a receiving device that performs wireless communication with a transmitting device in a spread spectrum communication system, and is characterized by: Include: The first step of the band limiting unit performing band limiting on the received signal, that is, the received signal, which is transmitted and received by the transmission device, and extracting a signal of a desired frequency band; and The timing synchronization unit generates a known sequence for correlation processing including all or a part of the synchronization chirp signal for timing synchronization generated by the transmission device, and performs the signal of the desired frequency band and the known sequence for the correlation processing. The correlation value obtained by the correlation processing of the sequence is detected, and the peak of the correlation value is detected, and the second step of timing synchronization is performed for specifying the head position of the receiving frame included in the receiving signal.

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