COMMUNICATION DEVICE, COMMUNICATION SYSTEM, COMMUNICATION METHOD, AND COMPUTER-READABLE STORAGE MEDIUM

Abstract

This communication device comprises: a storage means for storing information indicating a first basic set including a first basic sequence to an Nth basic sequence; a shifting means for generating a first shift sequence to an Nth shift sequence by determining a shift amount on the basis of transmission data and cyclically shifting the nth basic sequence (n is an integer from 1 to N) by the shift amount; a holding means for holding timing information indicating transmission timing of the series; and a transmitting means for transmitting each shift sequence according to the timing information, wherein the first basic sequence to the Nth basic sequence satisfy a first condition that the sum of the correlation values of autocorrelation from the first basic sequence to the Nth basic sequence when the shift amount is 0 is different from 0, and the sum of correlation values of autocorrelation from the first basic sequence to the Nth basic sequence with the shift amount different from 0 used for data transmission is 0.

Description

[Technical Field]

[0001] The present disclosure relates to communications technology. [Background technology]

[0002] For example, IoT (Internet of Things) devices used in smart meters and the like are placed in various geographical locations, and one access point (AP) communicates with multiple IoT devices. Non-Patent Document 1 discloses a communication technology called LoRa that is used in IoT devices and the like. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] SEMTECH,"AN1200.22 LoRaTM Modulation Basics", May 2015 Summary of the Invention [Problem to be solved by the invention]

[0004] In the communication technology disclosed in Non-Patent Document 1, when the number of IoT devices communicating with an AP increases, the number of packets that the AP can successfully receive is limited due to the effects of interference, etc. For example, if one AP communicates with 500 IoT devices and each IoT device sends 1,500 packets per hour, the number of packets that the AP can successfully receive is approximately 200 packets per IoT device.

[0005] Therefore, there is a demand for new communication technologies that can suppress the effects of interference and the like. [Means for solving the problem]

[0006] According to one embodiment of the present disclosure, a communication device includes: storage means for storing information indicating a first basic set including a first basic sequence to an N-th basic sequence (N is an integer greater than or equal to 2), which is a sequence of L (L is an integer greater than or equal to 2) complex numbers; shift means for determining a shift amount based on transmission data and generating the N-th shift sequence from the first shift sequence by cyclically shifting the n-th basic sequence (n is an integer from 1 to N) by the shift amount; storage means for holding timing information indicating sequence transmission timing; and transmission means for transmitting the first shift sequence to the N-th shift sequence in accordance with the timing information, wherein the first basic sequence to the N-th basic sequence satisfy a first condition that the sum of autocorrelation correlation values ​​from the first basic sequence to the N-th basic sequence at a shift amount of 0 is different from 0, and the sum of autocorrelation correlation values ​​from the first basic sequence to the N-th basic sequence at a shift amount different from 0 used to transmit data is zero.

[0007] Other features and advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings, in which the same or similar elements are designated by the same reference numerals.

[0008] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a configuration diagram of a wireless communication system used to explain an embodiment. [Figure 2] FIG. 1 is a diagram illustrating the configuration of a transmitting side of a wireless device. [Figure 3] A diagram showing an example of a basic set. [Figure 4] FIG. 10 is a diagram showing an example of a shift set. [Figure 5] 10A to 10C are diagrams showing examples of transmission of each shift sequence. [Figure 6] FIG. 1 is a diagram illustrating the configuration of the receiving side of an access point. [Figure 7] FIG. 10 is a diagram showing an example of correlation values ​​of periodic correlation. [Figure 8] FIG. 1 is a diagram illustrating the configuration of the transmitting side of an access point. [Figure 9] FIG. 10 is a diagram showing another example of a basic set. [Figure 10] FIG. 10 is a diagram showing an example of an addition set. [Figure 11] FIG. 1 is a diagram illustrating the configuration of the receiving side of a wireless device. [Figure 12] FIG. 10 is a diagram showing another example of correlation values ​​of periodic correlation. [Figure 13] FIG. 10 is a diagram showing still another example of correlation values ​​of periodic correlation. [Figure 14] FIG. 10 is a diagram showing another example of a basic set. [Figure 15] FIG. 10 is a diagram showing still another example of correlation values ​​of periodic correlation. [Figure 16] FIG. 10 is a diagram showing an example of mapping information. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the invention as claimed, and not all combinations of features described in the embodiments are necessarily essential to the invention. Two or more of the features described in the embodiments may be combined in any desired manner. Furthermore, the same reference numerals are used to designate identical or similar components, and redundant descriptions will be omitted.

[0011] First Embodiment FIG. 1 is a configuration diagram of a wireless communication system used to explain an embodiment. An access point (AP) 2 is a communication device capable of wireless communication with wireless devices (WDs) 1-1 to 1-3. WDs 1-1 to 1-3 are communication devices capable of wireless communication with AP 2. As an example, WDs 1-1 to 1-3 are IoT devices. In the following explanation, WDs 1-1 to 1-3 are also collectively referred to as WD1. In FIG. 1, AP 2 communicates with three WDs 1, but this is an example, and the number of WDs with which AP 2 communicates may be one or more. In the following explanation, the direction from WD 1 to AP 2 is referred to as the uplink direction, and the direction from AP 2 to WD 1 is referred to as the downlink direction.

[0012] <Upstream communication> FIG. 2 is a configuration diagram of the transmitting side of WD1. FIG. 2 can also be regarded as the configuration of a modulator included in WD1. For example, when WD1 initially accesses AP2, it receives from AP2 basic set information indicating a basic set including N basic sequences and uplink timing information associated with the basic set. Note that the initial access can be performed using any existing communication method (modulation method). Storage unit 13 stores the basic set information received from AP2. Furthermore, timing information holding unit 14 holds the uplink timing information received from AP2. Storage unit 13 and timing information holding unit 14 can be any volatile or nonvolatile memory device.

[0013] The basic set includes a first basic sequence through an N-th basic sequence, and each basic sequence is a sequence of L complex values. N and L are each an integer greater than or equal to 2. The conditions that the N basic sequences must satisfy will be described later. The following explanation will be given taking an example where N=4 and L=4. FIG. 3 shows an example of a basic set indicated by the basic set information stored in storage unit 13. Since N=4, the basic set includes four basic sequences, the first basic sequence through the fourth basic sequence. According to FIG. 3, the first basic sequence is (1, 1, 1, 1), and the second basic sequence is (1, j, -1, -j). The basic set information further indicates the frequencies associated with the first basic sequence through the fourth basic sequence. According to FIG. 3, the first basic sequence through the fourth basic sequence are associated with frequencies f1 through f4, respectively.

[0014] The shift unit 11 performs a shift operation to cyclically shift each basic sequence of the basic set by a shift amount determined based on the data to be transmitted. In the following description, a sequence obtained by the shift operation of a basic sequence will be referred to as a "shift sequence." Furthermore, a set including N (four in this example) shift sequences will be referred to as a "shift set." The shift operation may be a left cyclic shift or a right cyclic shift. In the following, the shift operation will be assumed to be a left cyclic shift. Furthermore, unless it is explicitly stated or implied that it is not a left cyclic shift, "shift" will mean a left cyclic shift. The shift unit 11 outputs the shift set to the transmitter 12.

[0015] In this example, since L=4, the number of possible shifts (shift amounts) is four, from 0 to 3. Therefore, when L=4, 2 bits of data (transmission data) can be transmitted in one transmission. Generally speaking, when the length of each base sequence is L, the number of bits that can be transmitted in one transmission is log2L or less. In the following description, it is assumed that the shift unit 11 performs a shift operation using a value in which 2 bits are regarded as a binary number as the shift amount. For example, when the transmission data is "10," the shift unit 11 shifts each of the first to fourth base sequences by 2. Therefore, the first to fourth shift sequences included in the shift set are as shown in FIG. 4. Note that in this embodiment, the shift amount is illustratively a value in which 2 bits are regarded as a binary number. For example, a configuration is possible in which an arbitrary correspondence relationship between four patterns that can be expressed by 2 bits and four shift amounts is determined in advance, and the shift amount is determined according to the correspondence relationship.

[0016] The uplink timing information held by the timing information holding unit 14 is information that specifies the transmission timing (transmission start timing) of each shift sequence. The transmitting unit 12 transmits each shift sequence at an associated frequency in accordance with the transmission timing indicated by the uplink timing information. Note that the frequency associated with a shift sequence is the frequency associated with the basic sequence from which the shift sequence is derived. For this reason, the transmitting unit 12 is configured to access the basic set information stored in the storage unit 13 and acquire frequency information indicating the frequency associated with each basic sequence.

[0017] In this embodiment, one complex number of each shifted sequence is transmitted in one chip, and the period of one chip is referred to as a chip period. In this example, the uplink timing information specifies the transmission timing of each shifted sequence as a multiple of the chip period. The maximum value T of the timing information is predetermined, and in this example, the maximum value T is set to 29. When the transmission timing of a shifted sequence is t (t is any value from 1 to T), this means that the shifted sequence is transmitted from the start timing of the t-th chip period.

[0018] For example, assume that the uplink timing information indicates that the transmission timings of the first shifted sequence, the second shifted sequence, the third shifted sequence, and the fourth shifted sequence are t=9, 2, 29, and 13, respectively. In this case, the transmitter 12 transmits each shifted sequence at an associated frequency, as shown in FIG.

[0019] For example, the transmitter 12 can map each complex value of the shifted sequence to the amplitude and phase of a frequency associated with the shifted sequence and transmit the mapped sequence. For example, in the case of the second shifted sequence transmitted at frequency f2 in Fig. 5, the transmitter 12 transmits a sine wave (frequency f2) having an amplitude of a predetermined value A and a phase of 180 degrees at t = 2, a sine wave (frequency f2) having an amplitude of a predetermined value A and a phase of 270 degrees at t = 3, a sine wave (frequency f2) having an amplitude of a predetermined value A and a phase of 0 degrees at t = 4, and a sine wave (frequency f2) having an amplitude of a predetermined value A and a phase of 90 degrees at t = 5, thereby transmitting the second shifted sequence.

[0020] Before transmitting data, WD1 transmits a predetermined preamble and its own identifier. In this embodiment, the start timing of the first chip, i.e., t=1, is set to the timing when transmission of this predetermined preamble and identifier is completed. When AP2 receives the predetermined preamble and the WD1's identifier from WD1, it receives a signal from WD1, with the completion of this reception as the start timing of t=1. In the example of FIG. 5, one transmission is completed in a 32-chip period.

[0021] The uplink timing information may be generated by the AP2 or may be stored in advance in the AP2. If the AP2 generates the uplink timing information, the AP2 can generate the uplink timing information by, for example, randomly generating the transmission timing t of each shift sequence within a range of 1 to a maximum value (29 in this example). The uplink timing information can be generated so that the transmission timing t of each shift sequence is different from each other, or so that there is no overlapping period in the transmission of each shift sequence. Furthermore, if the AP2 communicates with multiple WD1s, the uplink timing information for each WD1 can be generated so that the transmission timing of the signal (shift sequence) transmitted by each WD1 at the same frequency is different. For example, the AP2 can be configured to generate the uplink timing information separately for each WD1. Furthermore, if the uplink timing information is stored in advance in the AP2, multiple different uplink timing information can be stored, and the AP2 can select the uplink timing information to use in communication with one WD1 from the multiple uplink timing information.

[0022] FIG. 6 shows the configuration of the receiving side of AP2. FIG. 6 can also be considered as the configuration of a demodulator possessed by AP2. The timing information holding unit 24 is, for example, a volatile or nonvolatile memory device, and holds the uplink timing information notified to WD1. When AP2 generates the uplink timing information, AP2 has a generator (not shown) that generates the uplink timing information. The storage unit 23 is, for example, a volatile or nonvolatile memory device, and stores the basic set information notified to WD1. Upon receiving a preamble and the identifier of WD1 from WD1, the receiver 25 receives each shifted sequence transmitted by WD1 as a received sequence in accordance with the uplink timing information notified to WD1. Thus, for AP2, the uplink timing information is information indicating the timing at which AP2 receives the first to Nth shifted sequences transmitted by WD1 as the first to Nth received sequences. The receiver 25 acquires the frequency of each shifted sequence from the basic set information stored in the storage unit 23. The receiving unit 25 outputs a receiving set including each of the received receiving sequences to the determining unit 26. For example, if there is no influence of interference, noise, or the like in the wireless section and the receiving unit 25 receives each of the shifted sequences shown in Fig. 4 transmitted by WD1 without error, the receiving unit 25 outputs each of the shifted sequences shown in Fig. 4 to the determining unit 26 as a receiving sequence.

[0023] The determination unit 26 determines and outputs the data transmitted by the WD1 based on the basic set and the receiving set indicated by the basic set information stored in the storage unit 23. The processing in the determination unit 26 will be described below.

[0024] First, the decision unit 26 finds the cyclic correlation of the nth basic sequence with respect to the nth received sequence. Here, n is an integer between 1 and N, and in this example, N=4. In addition, in this example, L=4, so the cyclic correlation includes four correlation values ​​when the shift amount τ is 0 to 3. Note that when the A sequence is (a0, a1, a2, a3) and the B sequence is (b0, b1, b2, b3), the correlation value at τ=0 is a0×b0 * +a1×b1 * +a2×b2 * +a3×b3 *and the correlation value at τ=1 is a0×b1 * +a1×b2 * +a2×b3 * +a3×b0 * where the value b * is the complex conjugate of the value b.

[0025] Fig. 7 shows each correlation value when the received set is the same as the shift set shown in Fig. 4. Note that "first" in Fig. 7 indicates each correlation value of the periodic correlation of the first basic sequence with respect to the first received sequence, "second" indicates each correlation value of the periodic correlation of the second basic sequence with respect to the second received sequence, "third" indicates each correlation value of the periodic correlation of the third basic sequence with respect to the third received sequence, and "fourth" indicates each correlation value of the periodic correlation of the fourth basic sequence with respect to the fourth received sequence.

[0026] The decision unit 26 finds the sum of correlation values ​​with the same shift amount τ among the cyclic correlations found for each sequence. The "total" in FIG. 7 indicates the sum of correlation values ​​with the same shift amount τ for each sequence. As shown in FIG. 7, the sum of the correlation values ​​is 16 when τ=2, but is 0 when τ=0, 1, or 3. Therefore, the decision unit 26 determines that the receiving set has cyclically shifted each basic sequence of the basic set by τ=2 to the left, and therefore determines that the data transmitted by WD1 (received data) is "10."

[0027] Next, the conditions that each basic sequence included in one basic set must satisfy will be described. In this embodiment, each basic sequence included in a basic set satisfies the following Condition 1. Condition 1: The autocorrelation, that is, the sum of the cyclic autocorrelation of the nth basic sequence with respect to the nth basic sequence included in the basic set across the 1st to Nth basic sequences for the same shift amount τ, is different from 0 when shift amount τ=0, and is 0 when shift amount τ is other than 0.

[0028] For example, when not using all L shift amounts from 0 to (L-1) for data transmission, but only Z shift amounts smaller than L are used for data transmission (for example, when only shift amounts from 0 to (Z-1) are used), Condition 1 is modified to the following Condition 1'. Condition 1': The autocorrelation, that is, the sum of the cyclic autocorrelation of the nth base sequence with respect to the nth base sequence included in the base set across the 1st to Nth base sequences for the same shift amount τ, is different from 0 when shift amount τ=0, and is 0 for shift amounts other than 0 used in data transmission (reception). In the following description, it is assumed that all of the L shift amounts are used for data transmission, and therefore, condition 1 is used.

[0029] By setting each basic sequence of the basic set in this way, the receiving side can determine the shift amount in the shift operation on the transmitting side based on the periodic correlation between the receiving set and the basic set. More specifically, the determination unit 26 determines that the shift amount with the largest absolute value of the "total" shown in Figure 7 is the shift amount in the shift operation on WD1, and can determine the data transmitted by WD1.

[0030] The correlation values ​​shown in FIG. 7 are obtained on the receiving side in an ideal case where there is no interference or the like in the wireless section. The received sequence that AP2 actually receives from WD1 will not be the same as the shifted sequence due to the effects of interference, noise, and the like. For example, if the reception conditions at frequencies f1 to f3 are good but there is interference / noise or the like at frequency f4, the error between the first to third received sequences and the first to third shifted sequences will be small, but the error between the fourth received sequence and the fourth shifted sequence will be large. In this case, for example, in the "total" shown in FIG. 7, τ=0, 1, 3 will not be 0, and the absolute value of τ=2 may be smaller than 16. However, as long as the absolute value of τ=2 is larger than the absolute value of τ=0, 1, 3, the data can be correctly determined.

[0031] In this embodiment, the uplink timing information of each WD1 is set so that the transmission timings of the shifted sequences transmitted by each WD1 at the same frequency are different from each other, so the probability that all of the shifted sequences transmitted by a certain WD1 will be affected by interference from other WD1 is low. Therefore, even if the number of WD1s communicating with one AP2 increases, the influence of interference, etc. can be suppressed. Furthermore, in this embodiment, by making the transmission frequencies of each shifted sequence different, the probability that all of the shifted sequences transmitted by a certain WD1 will be affected by interference from other WD1 is further reduced.

[0032] In this embodiment, different frequencies are associated with the first to Nth basic sequences included in the basic set. The WD1 then transmits each shifted sequence to the AP2 at the frequency associated with the original basic sequence. However, this embodiment is not limited to this configuration. For example, each shifted sequence can be transmitted at the same frequency. Alternatively, a first frequency can be associated with some of the first to Nth basic sequences, and a second frequency different from the first frequency can be associated with the remaining basic sequences. In other words, a configuration in which fewer than N frequencies are associated with the first to Nth basic sequences is possible. For multiple shifted sequences associated with the same frequency, uplink timing information is generated so that there is no overlap in the transmission of these multiple shifted sequences. Even when different frequencies are associated with the first to Nth basic sequences, there is also a configuration in which uplink timing information is generated so that there is no overlap in the transmission of each shifted sequence. Generating uplink timing information in this manner can alleviate the requirements for filters, etc., required on the receiving side.

[0033] <Downstream communication> FIG. 8 is a configuration diagram of the transmitting side of AP2. FIG. 8 can also be regarded as the configuration of a modulator possessed by AP2. In the following, an example will be described in which AP2 communicates with two WD1s, WD1-1 and WD1-2, and transmits data to each of these two WD1s. The basic set information stored in the storage unit 13 of WD1-1 indicates the basic set shown in FIG. 3. On the other hand, the basic set information stored in the storage unit 13 of WD1-2 indicates the basic set shown in FIG. 9. In the following, the basic set shown in FIG. 3 used by WD1-1 will be referred to as basic set #1, and the basic set shown in FIG. 9 used by WD1-2 will be referred to as basic set #2. The storage unit 23 of AP2 stores basic set information indicating basic set #1 and basic set #2 notified to WD1-1 and WD1-2, respectively.

[0034] In this embodiment, basic set #2 is obtained by cyclically shifting each basic sequence of basic set #1. That is, the first basic sequence of basic set #2 is the second basic sequence of basic set #1, the second basic sequence of basic set #2 is the third basic sequence of basic set #1, the third basic sequence of basic set #2 is the fourth basic sequence of basic set #1, and the fourth basic sequence of basic set #2 is the first basic sequence of basic set #1. The first to fourth basic sequences of basic set #2 are associated with frequencies f1 to f4, respectively.

[0035] The shift unit 21 performs a shift operation on each basic sequence of the basic set #1 in the data #1 (first transmission data) to be transmitted to WD1-1, and outputs a shift set #1 including the first shift sequence #1 to the fourth shift sequence #1 to the adder 27. The shift operation in the shift unit 21 is the same as the shift operation performed by the shift unit 11 of WD1. For example, when bits "10" are transmitted to WD1-1, the shift set #1 is as shown in FIG.

[0036] Similarly, the shift unit 21 performs a shift operation on each basic sequence of basic set #2 in data #2 (second transmission data) to be transmitted to WD1-2, and outputs shift set #2 including first shift sequence #2 to fourth shift sequence #2 to the adder 27. For example, when bits "00" are transmitted to WD1-2, shift set #2 remains the basic set #2 shown in FIG.

[0037] The adder 27 adds the nth shift sequence of shift set #1 and the nth shift sequence of shift set #2 to generate the nth sum sequence, and outputs the sum set including the first to fourth sum sequences to the transmitter 22. Fig. 10 shows each sum sequence of the sum set.

[0038] The timing information holding unit 24 holds downlink timing information. The downlink timing information is used for transmission in the downlink direction, and like the uplink timing information, indicates the transmission timing (transmission start timing) of each added sequence. Like the uplink timing information, the downlink timing information may be generated by the AP2, or may be generated in advance and stored in the AP2. The AP2 notifies each WD1 of the downlink timing information along with the uplink timing information. The transmitting unit 22 transmits each added sequence in accordance with the downlink timing information.

[0039] FIG. 11 shows the configuration of the receiving side of WD1. FIG. 11 can also be considered as the configuration of a demodulator possessed by WD1. The timing information holding unit 14 holds downlink timing information received from AP2. The receiving unit 15 receives each added sequence transmitted by AP2 as a received sequence in accordance with the downlink timing information. For WD1, the downlink timing information is information indicating the timing at which WD1 receives the first to Nth added sequences transmitted by AP2 as the first to Nth received sequences. The receiving unit 15 outputs a received set including each received sequence to the determining unit 16. For example, assuming that there is no interference or noise in the wireless section and the receiving unit 15 receives each added sequence shown in FIG. 10 transmitted by AP2 without error, the receiving unit 15 outputs each added sequence shown in FIG. 10 to the determining unit 16 as a received sequence.

[0040] Basic set information indicating the basic set is stored in the storage unit 13. In the case of WD1-1, the basic set information indicates basic set #1, and in the case of WD1-2, the basic set information indicates basic set #2. The processing performed by the determination unit 16 is the same as that performed by the determination unit 26.

[0041] FIG. 12 shows the correlation values ​​of the cyclic correlation between the nth received sequence of the receiving set and the nth basic sequence of basic set #1, and the sum of the correlation values ​​with the same shift amount τ, when the addition set shown in FIG. 10 is received as the receiving set without error. From the results shown in FIG. 12, WD1-1 can determine that the transmission data is "10." Furthermore, FIG. 13 shows the correlation values ​​of the cyclic correlation between the nth received sequence of the receiving set and the nth basic sequence of basic set #2, and the sum of the correlation values ​​with the same shift amount τ, when the addition set shown in FIG. 10 is received as the receiving set without error. From the results shown in FIG. 13, WD1-2 can determine that the transmission data is "00." In this way, AP2 can simultaneously transmit data to WD1-1 and WD1-2 using the same downlink timing information.

[0042] Next, we will explain the conditions that basic set #1 and basic set #2 must meet in order to simultaneously transmit data to WD1-1 and WD1-2. Basic set #1 and basic set #2 are each set to meet the following condition 2 in addition to the above condition 1. Condition 2: The sum of the cross-correlation values, i.e., the periodic cross-correlation between the nth base sequence included in base set #1 and the nth base sequence included in base set #2, at the same shift amount τ from the 1st base sequence to the Nth base sequence is 0 for all shift amounts τ.

[0043] For example, when not using all L shift amounts from 0 to (L-1) for data transmission, but only Z shift amounts smaller than L are used for data transmission (for example, when only shift amounts from 0 to (Z-1) are used), condition 2 is modified to the following condition 2'. Condition 2': The sum of the cross-correlation values, i.e., the cyclic cross-correlation between the nth base sequence included in base set #1 and the nth base sequence included in base set #2 at the same shift amount τ from the 1st base sequence to the Nth base sequence, is 0 for all (Z) shift amounts τ used in data transmission (reception). In the following description, it is assumed that all of the L shift amounts are used for data transmission, and therefore condition 2 is used.

[0044] In this embodiment, basic set #2 is obtained by cyclically shifting basic set #1. Here, the cross-correlation of basic set #1 shown in FIG. 3 is 0 for all shift amounts τ=0. Therefore, it is clear that basic set #1 and basic set #2, which is obtained by cyclically shifting basic set #1, satisfy condition 2.

[0045] More generally, AP2 can communicate with M WD1s using M basic sets (M is an integer equal to or greater than 2). Each of the M basic sets satisfies the above condition 1. Furthermore, any two of the M basic sets satisfies the above condition 2. The M basic sets can be generated in various ways. As an example, as shown in FIG. 3, one basic set is set using an arbitrary method, including N basic sequences that satisfy condition 1 and whose cross-correlation is zero for all shift amounts τ. Then, M basic sets #1 to #M (M is an integer from 2 to N) can be generated by cyclically shifting the basic sequences of the basic set.

[0046] Then, AP2 notifies M WD1s of basic sets #1 to #M. AP2 also notifies each of M WD1s of individual uplink timing information and common downlink timing information. The uplink timing information notified to each of M WD1s can be set so that the transmission timing of the shifted sequence transmitted by each of M WD1s at the same frequency is different. Each WD1 uses the received basic set to transmit in the uplink direction according to the notified uplink timing information. Each WD1 also uses the received basic set to receive in the downlink direction according to the notified downlink timing information. AP2 also receives a shifted set from a WD1 according to the notified uplink timing information and determines data from the WD1 using the basic set notified to the WD1. AP2 also generates a shifted set for each of M WD1s using the basic set notified to M WD1s, generates an added set based on the shifted set for each WD1, and transmits the added set according to the downlink timing information notified to M WD1s, thereby transmitting data to each of M WD1s.

[0047] Although individual frequencies are assigned to each basic sequence in the basic set in the downlink communication, the same frequency can be assigned to each basic sequence in the basic set as explained in the uplink communication.Furthermore, a configuration can be adopted in which fewer frequencies than the number of basic sequences are used.

[0048] Furthermore, in this embodiment, the same frequencies f1 to f4 are used in the uplink and downlink communications, but the frequencies used in the uplink communications and the frequencies used in the downlink communications can be different, that is, frequency division duplexing (FDD) can be used. In this case, the frequencies f1 to f4 are mapped to different frequencies in the uplink and downlink communications.

[0049] For example, the uplink timing information and downlink timing information can be encrypted and notified to the WD 1. By concealing the frequency and transmission timing of each series from third parties, it becomes difficult for third parties to decipher the data transmitted and received between the WD 1 and the AP 2.

[0050] Second Embodiment Next, the second embodiment will be described, focusing on the differences from the first embodiment. In this embodiment, downlink communication differs from the first embodiment. The transmitting side configuration of AP2 in this embodiment corresponds to one in which the adder 27 in FIG. 8 is omitted. In addition, in this embodiment, basic set #2 used in communication with WD1-2 is assumed to be that shown in FIG. 14. The first to fourth basic sequences of basic set #2 are the same as those shown in FIG. 9, but the frequencies associated with the first to fourth basic sequences differ from those in FIG. 9. That is, in the first embodiment, the frequency associated with the nth basic sequence of basic set #1 was the same as the frequency associated with the nth basic sequence of basic set #2, but in this embodiment, the frequency associated with the nth basic sequence of basic set #1 is different from the frequency associated with the nth basic sequence of basic set #2.

[0051] Since the adder 27 is not provided, the shifter 21 transmits the shift sets #1 and #2 to the transmitter 22. The transmitter 22 transmits each shifted sequence of the shift set #1 at an associated frequency in accordance with the downlink timing information, and transmits each shifted sequence of the shift set #2 at an associated frequency. Therefore, for example, the first shifted sequence of the shift set #1 is transmitted at frequency f1, and the first shifted sequence of the shift set #2 is transmitted at frequency f2. Note that since the shift sets #1 and #2 are transmitted according to the same downlink timing information, the n-th shifted sequence of the shift set #1 and the n-th shifted sequence of the shift set #2 are transmitted in the same period.

[0052] The configuration of the receiving side of WD1 in this embodiment is the same as that shown in FIG. 11, and WD1 receives each shifted sequence addressed to itself in accordance with the downlink timing information. Specifically, WD1-1 receives the first shifted sequence at frequency f1 in accordance with the downlink timing information. During the same period, AP2 transmits the first shifted sequence addressed to WD1-2 at frequency f2, but because the frequencies are different, WD1-1 does not receive the first shifted sequence addressed to WD1-2. Note that even if WD1-1 receives the first shifted sequence addressed to WD1-2 due to the filter performance of WD1-1, there is no problem due to condition 2 described in the first embodiment. The same applies to WD2-2.

[0053] In this embodiment, the frequencies of the nth basic sequence in basic set #1 and the nth basic sequence in basic set #2 are different, but they may be the same. In this case, WD1 also receives shifted sequences addressed to other WD1s, but this does not pose a problem due to condition 2.

[0054] Third Embodiment Next, differences from the first and second embodiments will be mainly described. In the first and second embodiments, M basic sets #1 to #M are used, and an AP 2 communicates with up to M WDs 1. In this embodiment, one AP 2 communicates with more than M WDs 1. In this embodiment, the WDs 1 are grouped into clusters including up to M WDs 1. Note that the number of WDs included in one cluster may be one. A different basic set out of the M basic sets is assigned to each of the M or fewer WDs included in one cluster. On the other hand, the same basic set out of the M basic sets may be assigned to WDs belonging to different clusters.

[0055] For uplink communications, the same uplink timing information is set for WD1s included in the same cluster. On the other hand, different uplink timing information is set for WD1s included in different clusters. That is, the uplink timing information is set so that the transmission timings of signals transmitted at the same frequency in the uplink direction are different between WD1s included in different clusters. Up to M WD1s included in the same cluster transmit their respective shift sequences at the same timing, but the above conditions 1 and 2 allow the AP2 to demodulate signals from up to M WD1s included in the same cluster. Furthermore, because signals of the same frequency are transmitted at different timings between WD1s included in different clusters, excessive interference can be suppressed.

[0056] Note that downlink communication to up to M WDs included in the same cluster is the same as in the first and second embodiments. On the other hand, downlink timing information is set for WDs included in different clusters so that the transmission timings of signals transmitted at the same frequency in the downlink direction are different. In other words, different downlink timing information is set for different clusters. Therefore, excessive interference of downlink signals between WDs included in different clusters can be prevented.

[0057] <Fourth embodiment> In each of the above embodiments, one basic set out of M basic sets is assigned to one WD1. In this embodiment, two or more different basic sets out of the M basic sets are assigned to one WD1. In the following description of this embodiment, unless otherwise clear from the context or specified, a WD1 assigned two or more basic sets will be simply referred to as a "WD1." Uplink timing information associated with each basic set is assigned to the WD1. For example, when two basic sets, a first basic set and a second basic set, are assigned to one WD1, first uplink timing information associated with the first basic set and second uplink timing information associated with the second basic set are set to the WD1. For example, in the example of FIG. 5, WD1 transmits two bits of data in a 32-chip period. However, by assigning two basic sets to WD1, WD1 can transmit four bits of data in a 32-chip period.

[0058] The plurality of uplink timing information corresponding to each of the plurality of different basic sets assigned to WD1 may be the same. Even if the plurality of uplink timing information corresponding to each of the plurality of different basic sets is the same, AP2 can demodulate the data from WD1 due to the above conditions 1 and 2. Alternatively, the plurality of uplink timing information corresponding to each of the plurality of different basic sets is set so that the transmission timings of the shifted sequences of different basic sets transmitted at the same frequency are different from each other. As an example, the plurality of uplink timing information corresponding to each of the plurality of different basic sets may be set so that the shifted sequences of different basic sets transmitted at the same frequency do not overlap in time.

[0059] Note that assigning multiple different basic sets to one WD1 and uplink timing information associated with the multiple basic sets corresponds to performing communication in the uplink direction similar to the downlink communication described in the second embodiment. The difference from the second embodiment is that, in the second embodiment, AP2 transmits data to different WD1s using each basic set, whereas a WD1 to which multiple basic sets are assigned transmits data to the same AP2 using each basic set. Furthermore, in the downlink communication described in the second embodiment, the same downlink timing information is associated with each basic set, but in uplink communication using a WD1 to which multiple basic sets are assigned, different uplink timing information associated with each of the multiple basic sets can be assigned, as described above.

[0060] Regarding data reception, the AP2 of the second embodiment receives reception sequences based on different basic sets notified to each of the multiple WD1s in accordance with uplink timing information notified to each of the multiple WD1s. The uplink timing information notified to each WD1 is set so that the reception timing (reception start timing) of reception sequences received at the same frequency from each WD1 is different from each other. Furthermore, the AP2 of the third embodiment receives reception sequences based on different basic sets in accordance with the same uplink timing information from different WD1s in the same cluster.

[0061] In this embodiment, the AP2 receives reception sequences based on different basic sets according to the same uplink timing information from the same WD1. Alternatively, the AP2 receives reception sequences based on different basic sets according to different uplink timing information from the same WD1. The different uplink timing information is set so that, among the reception sequences received from the same WD1, reception sequences received at the same frequency have different reception timings. As an example, the different uplink timing information can be set so that the reception periods of different reception sequences at the same frequency from the same WD1 do not overlap in time. Note that the WD1 in this embodiment receives reception sequences based on different basic sets according to the same downlink timing information from the same AP2. Alternatively, the WD1 in this embodiment receives reception sequences based on different basic sets according to different downlink timing information from the same AP2. The different downlink timing information is set so that, among the reception sequences received from the same AP2, reception sequences received at the same frequency have different reception timings. As an example, the reception periods of different reception sequences at the same frequency do not overlap in time.

[0062] When multiple basic sets are assigned to the same WD1, the WD1 can also transmit an added sequence obtained by adding shifted sequences based on each basic set to the AP 2, similar to the downstream communication in the first embodiment. In this case, the upstream timing information indicates the transmission timing of the added sequence.

[0063] Fifth Embodiment Next, a fifth embodiment will be described, focusing on the differences from the above embodiments. In the above embodiments, the length of each basic sequence in the basic set is set to L, and data of log 2 L bits or less is transmitted to one communication device as a single communication partner in one communication. In this embodiment, the length of each basic sequence in the basic set remains L, but the number of bits that can be transmitted to one communication device in one communication is increased to more than log 2 L bits.

[0064] In the following, an embodiment will be described using an example in which WD1 transmits three bits of data "110" and three bits of data "010" to AP2 in one communication. It is assumed that the basic set used by WD1 is as shown in FIG. 3. The shift unit 11 of WD1 converts the basic sequences into intermediate sequences by multiplying the complex number of each basic sequence of the basic set by a value corresponding to the first bit of the three bits. In the following, as an example, if the first bit is "1", it is multiplied by 1, and if the first bit is "0", it is multiplied by -1. Next, the shift unit 11 determines the shift amount by converting the last two bits of the three bits into a binary number, and generates each shifted sequence by shifting each intermediate sequence by the shift amount. The shift set including each shifted sequence is then transmitted to the transmitter 12.

[0065] In the case of data "110", the first bit is "1", so each intermediate sequence is the same as the basic sequence. Therefore, the shift unit 11 shifts the intermediate sequence (basic sequence) by 2 based on the last two bits, "10". Therefore, the shift set output to the transmitter 12 is as shown in FIG. 4. On the other hand, in the case of data "010", the first bit is "0", so the shift unit 11 inverts the sign of each basic sequence and performs a shift operation with a shift amount of 2. Therefore, the shift set output to the transmitter 12 is obtained by inverting the sign of each shift sequence of the shift set in FIG. 4. Note that in this example, each basic sequence of the basic set is multiplied by a multiplier corresponding to the bit and then the shift operation is performed, but the same result can be obtained by multiplying by a multiplier corresponding to the bit after the shift operation.

[0066] The receiving configuration of AP2 according to this embodiment is the same as that of the first embodiment. Therefore, when WD1 transmits data "110," AP2 obtains the correlation value shown in FIG. 7. On the other hand, when WD1 transmits data "010," AP2 obtains the correlation value shown in FIG. 15. The determination unit 26 determines the last two bits based on the value of the shift amount τ that maximizes the absolute value of the sum of the correlation values. The determination unit 26 can also determine whether the first bit is "0" or "1" based on the sign of the shift amount τ that maximizes the absolute value. Note that in this example, if the first bit is "0," it is multiplied by -1. However, if it is multiplied by "2," for example, the sum for τ=2 in FIG. 15 becomes 32. Therefore, more specifically, the determination unit 26 determines whether the first bit is "0" or "1" based on the sum of the shift amounts τ that maximizes the absolute value.

[0067] Although the embodiment has been described in which WD1 transmits 3-bit data to AP2, when transmitting 4-bit data, the multiplier can be, for example, "1+j", "-1+j", "-1-j", or "1-j" depending on the value of the first 2 bits. In other words, the multiplier may be a complex number. In this case, the determination unit 26 determines the multiplier based on the total value (complex value) of the shift amount τ that maximizes the absolute value, and determines the bit corresponding to the multiplier. The absolute value of the complex number corresponds to the distance from the origin in the complex plane.

[0068] To summarize, in the first embodiment, the shift amount is determined based on P-bit data (P is an integer equal to or greater than 1), and P-bit data is transmitted in one communication. Note that P is an integer equal to or less than log2L. On the other hand, in this embodiment, (P+Q)-bit data (Q is an integer equal to or greater than 1) is transmitted in one communication. The shift unit 11 determines the shift amount based on P-bit data out of the (P+Q)-bit data. Also, the shift unit 11 determines a multiplier by which each complex number of each base sequence is multiplied based on Q-bit data out of the (P+Q)-bit data. Note that the number of multipliers is 2 QThen, the shift unit 11 generates each shifted sequence by multiplying each base sequence by a multiplier and performing a shift operation. Note that, among the first to (P+Q)th bits constituting the (P+Q) bits, how to select the Q bits used to determine the multiplier and the P bits used to determine the shift amount is arbitrary, and is not limited to a configuration in which the multiplier is determined by the first Q bits.

[0069] Meanwhile, the decision unit 26 of AP2 calculates the periodic correlation between the received sequence and the corresponding base sequence for each received sequence, and calculates the sum of correlation values ​​with the same shift amount. As in the first embodiment, the decision unit 26 determines P-bit data based on the shift amount with the largest absolute value of the sum. The decision unit 26 also determines a multiplier based on the sum of the shift amounts with the largest absolute value, and determines Q-bit data based on the determined multiplier. This configuration makes it possible to increase the amount of data transmitted in one communication compared to the first embodiment. Note that the communication method of this embodiment is applicable not only to the uplink direction but also to the downlink direction. It can also be applied to the configurations of the second to fourth embodiments.

[0070] Sixth Embodiment Next, the sixth embodiment will be described, focusing on the differences from the above embodiments. Like the fifth embodiment, this embodiment also increases the amount of data in one communication. For example, the length L (sequence length) of each basic sequence in the basic set is set to 5. In the case of the first embodiment, even if L is 5, the number of bits that can be transmitted in one communication is 2.

[0071] In this embodiment, as an example, consider a combination in which three are selected from five shift amounts τ of 0 to 4. FIG. 16 shows 10 combinations in which three are selected from five shift amounts τ. Note that in FIG. 16, "1" indicates that a combination has been selected. In this embodiment, as shown in FIG. 16, each of eight patterns expressed by 3-bit data is mapped to one of the 10 combinations. In FIG. 16, for example, "000" corresponds to the combination of shift amounts τ=2, 3, and 4.

[0072] When the transmission data is "000", the shift unit 11 generates shift set #1 by shifting each base sequence by a shift amount τ=2, generates shift set #2 by shifting each base sequence by a shift amount τ=3, and generates shift set #3 by shifting each base sequence by a shift amount τ=4, according to the mapping indicated by the mapping information in FIG. 16. Then, the nth shift sequences of shift sets #1 to #3 are added together to generate a shift set to be transmitted to the transmitter 12. The transmitter 12 transmits each shift sequence in accordance with uplink timing information, as in the first embodiment. Note that the mapping information is created in advance and stored in the storage unit 13. Alternatively, the mapping information is received from the AP 2 together with the uplink timing information, etc.

[0073] The storage unit 23 of AP2 also stores the mapping information shown in Fig. 16. The determination unit 26 calculates the periodic correlation between the received sequence and the corresponding base sequence using the process described in the first embodiment, and calculates the sum of the correlation values ​​for each sequence with the same shift amount. The determination unit 26 then determines the three shift amounts with the largest absolute values ​​of the sum. As is clear from the explanations in Figs. 12 and 13, when the received sequence is the same as the shifted sequence, the sums for shift amounts τ = 2, 3, and 4 are the same value and are greater than the sums for shift amounts τ = 0 and 1. Therefore, the determination unit 26 can determine that the transmission data of WD1 is "000" in accordance with the mapping information shown in Fig. 16.

[0074] In summary, in this embodiment, WD1 and AP2 have the same mapping information. The mapping information indicates the relationship between a predetermined number of combinations of shift amounts and P-bit data. The number of combinations is 2. Por more. The predetermined number is 2 or more and less than L (in the example of FIG. 16, the predetermined number is 3). When transmitting P-bit data, WD1 determines the predetermined number of shift amounts by referring to mapping information based on the data. Then, WD1 generates shift sets corresponding to each shift amount by shifting at each shift amount, and generates a shift set to be transmitted to the transmitter 12 by adding the shift sets corresponding to each shift amount. Meanwhile, AP2 determines the predetermined number of shift amounts by the cyclic correlation between the reception set and the basic set. Then, AP2 determines the data transmitted by WD1 by referring to mapping information based on the determined predetermined number of shift amounts.

[0075] This embodiment can be combined with the configurations described in the above embodiments. Furthermore, this embodiment can also be applied to downstream communications.

[0076] <Other> In each of the above embodiments, a configuration may be adopted in which a cyclic prefix (CP) is added to each shift sequence of a shift set transmitted by the WD1, that is, a configuration in which a CP based on the shift set is transmitted immediately before or after the shift set. As an example, the CPs are the last C (C is an integer equal to or less than L) CPs of the shift sequence. In this case, the WD1 transmits the CP immediately before the shift sequence. In other words, the WD1 generates and transmits a CP-added shift sequence by adding a CP immediately before the shift sequence. For example, if C=2, the CP-added shift sequence obtained by adding a CP to the second shift sequence in FIG. 4 becomes 1, j, -1, -j, 1, j. As another example, the CPs are the first C CPs of the shift sequence. In this case, the WD1 transmits the CP immediately after the shift sequence. In other words, the WD1 generates and transmits a CP-added shift sequence by adding a CP immediately after the shift sequence. The same applies to the downlink direction. By adding a CP, information can be demodulated accurately even in a multipath environment.

[0077] Furthermore, in each of the above embodiments, the WD1 receives the basic set from the AP2, but basic set information indicating the basic set can also be configured to be stored in advance in the WD1. In this case, the storage unit 13 can be a device that holds the basic set information in hardware, rather than a rewritable memory device. The same applies to the storage unit 23 of the AP2.

[0078] Furthermore, in each of the above embodiments, the WD1 and AP2 communicate wirelessly. However, the present invention is applicable to communication using, for example, sound waves or light, in addition to communication using radio signals in the radio frequency band. Furthermore, the communication methods and communication systems described in each of the above embodiments are provided.

[0079] Furthermore, a computer program is provided that causes an apparatus having one or more processors to function as the WD1 or AP2 described in each of the above embodiments. The computer program is stored in one or more memory devices of the apparatus, and includes program instructions that, when executed by one or more processors of the apparatus, cause the apparatus to function as the WD1 or AP2 described in each of the above embodiments. Furthermore, a computer program is provided that causes an apparatus having one or more processors to execute the communication method performed by the WD1 or AP2 described in each of the above embodiments. Furthermore, a non-transitory computer-readable storage medium storing these computer programs is provided.

[0080] The invention is not limited to the above-described embodiment, and various modifications and variations are possible within the scope of the gist of the invention.

Claims

1. A communication device, a storage means for storing information indicating a first basic set including a first basic sequence through an N-th basic sequence (N is an integer equal to or greater than 2), which are a sequence of L complex numbers (L is an integer equal to or greater than 2); shift means for determining a shift amount based on transmission data and cyclically shifting an nth basic sequence (n is an integer from 1 to N) by the shift amount to generate an nth shifted sequence, thereby generating an Nth shifted sequence from a first shifted sequence; a storage means for storing timing information indicating a transmission timing of the sequence; a transmitting means for transmitting the first to Nth shifted sequences in accordance with the timing information; Equipped with a communication device in which the first to Nth basic sequences satisfy a first condition that a sum of correlation values ​​of autocorrelation at a shift amount of 0 across the first to Nth basic sequences is different from 0, and a sum of correlation values ​​of autocorrelation at a shift amount different from 0 used in data transmission across the first to Nth basic sequences is zero.

2. The communication device according to claim 1 , wherein the transmission timings of the first to Nth shift sequences are different from each other.

3. each of the first shift sequence to the Nth shift sequence is associated with a frequency; The communication device according to claim 1 , wherein the transmitting means transmits each of the first to Nth shift sequences at the associated frequency.

4. The communication device according to claim 3 , wherein the frequencies associated with the first to Nth shift sequences are different from one another.

5. the frequencies associated with at least two of the first to Nth shift sequences are the same; The communication device according to claim 3 , wherein the transmission timings of the at least two shift sequences indicated by the timing information are set so that there is no overlapping period between the transmissions of the at least two shift sequences.

6. the transmission data is P-bit data, the shifting means determines the shift amount based on the P-bit data; The value of P is log ２ The communication device according to claim 1 , wherein the first and second inputs are equal to or smaller than L.

7. the transmission data is (P+Q)-bit data, the shift means determines the shift amount based on P-bit data of the (P+Q) bits and determines a multiplier based on Q-bit data of the (P+Q) bits, and the n-th shift sequence is obtained by multiplying the L complex numbers of the n-th base sequence by the multiplier and cyclically shifting the result by the shift amount; The value of P is log ２ The communication device according to claim 1 , wherein the first and second inputs are equal to or smaller than L.

8. the shifting means determines a predetermined number of different shift amounts based on the transmission data; the shift means generates the n-th shift sequence for each of the predetermined number of different shift amounts by performing a cyclic shift on the n-th base sequence by each of the predetermined number of different shift amounts, and generates the N-th shift sequence from the first shift sequence by adding the n-th shift sequences generated for each of the predetermined number of different shift amounts; The communication device according to claim 1 , wherein the predetermined number is a value equal to or greater than 2 and less than L.

9. 2. The communication device according to claim 1, wherein the timing information held by the holding means is received from a device to which the transmission data is to be sent.

10. 2. The communication device according to claim 1, wherein the first base sequence to the Nth base sequence stored in the storage means are received from a device to which the transmission data is to be sent.

11. The communication device according to claim 1 , wherein the transmitting means transmits a cyclic prefix based on the n-shifted sequence immediately before or after the n-shifted sequence.

12. the storage means further stores information indicating a second basic set including a first basic sequence to an N-th basic sequence, which are the sequence of the L complex numbers, and the first basic sequence to the N-th basic sequence of the second basic set satisfy the first condition; the storage means stores first timing information associated with the first basic set and second timing information associated with the second basic set; When the first transmission data and the second transmission data are transmitted to the same device, the shift means generates a first shift set including the N-shift sequence from the first shift sequence by cyclically shifting the n-th base sequence of the first basic set by a first shift amount based on the first transmission data, and generates a second shift set including the N-th shift sequence from the first shift sequence by cyclically shifting the n-th base sequence of the second basic set by a second shift amount based on the second transmission data; the transmitting means transmits the first to Nth shift sequences of the first shift set in accordance with the first timing information, and transmits the first to Nth shift sequences of the second shift set in accordance with the second timing information; 2. The communication device according to claim 1, wherein the first basic set and the second basic set satisfy a second condition that a sum of correlation values ​​of periodic correlation between the nth basic sequence of the first basic set and the nth basic sequence of the second basic set at the same shift amount across the first basic sequence to the Nth basic sequence is 0 for all shift amounts used in data transmission.

13. The communication device according to claim 12 , wherein the first timing information and the second timing information are set so that transmission timings of shift sequences transmitted at the same frequency in the first shift set and the second shift set are different.

14. The communication device of claim 12 , wherein the first timing information and the second timing information are the same information.

15. the storage means further stores information indicating a second basic set including a first basic sequence to an N-th basic sequence, which are the sequence of the L complex numbers, and the first basic sequence to the N-th basic sequence of the second basic set satisfy the first condition; When first transmission data is transmitted to a first communication device and second transmission data is transmitted to a second communication device different from the first communication device, the shift means generates a first shift set including the N-shift sequence from the first shift sequence by cyclically shifting the n-th base sequence of the first basic set by a first shift amount based on the first transmission data, and generates a second shift set including the N-th shift sequence from the first shift sequence by cyclically shifting the n-th base sequence of the second basic set by a second shift amount based on the second transmission data; the transmitting means generates an n-th added sequence by adding the n-th shifted sequence of the first shift set and the n-th shifted sequence of the second shift set, and transmits the first added sequence to the N-th added sequence in accordance with the timing information; 2. The communication device according to claim 1, wherein the first basic set and the second basic set satisfy a second condition that a sum of correlation values ​​of periodic correlation between the nth basic sequence of the first basic set and the nth basic sequence of the second basic set at the same shift amount across the first basic sequence to the Nth basic sequence is 0 for all shift amounts used in data transmission.

16. the storage means further stores information indicating a second basic set including a first basic sequence to an N-th basic sequence, which are the sequence of the L complex numbers, and the first basic sequence to the N-th basic sequence of the second basic set satisfy the first condition; When first transmission data is transmitted to a first communication device and second transmission data is transmitted to a second communication device different from the first communication device, the shift means generates a first shift set including the N-shift sequence from the first shift sequence by cyclically shifting the n-th base sequence of the first basic set by a first shift amount based on the first transmission data, and generates a second shift set including the N-th shift sequence from the first shift sequence by cyclically shifting the n-th base sequence of the second basic set by a second shift amount based on the second transmission data; the transmitting means transmits the first to Nth shift sequences of the first shift set and the first to Nth shift sequences of the second shift set according to the same timing information; 2. The communication device according to claim 1, wherein the first basic set and the second basic set satisfy a second condition that a sum of correlation values ​​of periodic correlation between the nth basic sequence of the first basic set and the nth basic sequence of the second basic set at the same shift amount across the first basic sequence to the Nth basic sequence is 0 for all shift amounts used in data transmission.

17. The communication device according to claim 1 , further comprising a generating means for generating the timing information.

18. A communication device, a storage means for storing information indicating a first basic set including a first basic sequence through an N-th basic sequence (N is an integer equal to or greater than 2), which are a sequence of L complex numbers (L is an integer equal to or greater than 2); a storage means for storing timing information indicating the reception timing of the sequence; receiving means for receiving a first reception sequence to an Nth reception sequence in accordance with the timing information; a determination means for determining a cyclic correlation between an n-th received sequence (n is an integer from 1 to N) and an n-th basic sequence, and determining received data based on a sum of correlation values ​​of the cyclic correlations of the same shift amount determined for the first to N-th received sequences; Equipped with a communication device in which the first to Nth basic sequences satisfy a first condition that a sum of correlation values ​​of autocorrelation from the first to Nth basic sequences when a shift amount is 0 is different from 0, and a sum of correlation values ​​of autocorrelation from the first to Nth basic sequences when a shift amount different from 0 is used for receiving data is zero.

19. The communication device according to claim 18 , wherein the reception timings of the first to Nth reception sequences are different from each other.

20. each of the first to Nth received sequences is associated with a frequency; 19. The communication device according to claim 18, wherein the receiving means receives each of the first to N reception sequences at the associated frequency.

21. The communication device according to claim 20 , wherein the frequencies associated with the first to Nth received sequences are different from one another.

22. the frequencies associated with at least two of the first to Nth received sequences are the same; 21. The communication device according to claim 20, wherein the reception timings of the at least two reception sequences are set so that there is no overlapping period during reception of the at least two reception sequences.

23. 19. The communication device according to claim 18, wherein said determining means determines said received data based on the shift amount that maximizes the absolute value of said sum.

24. 19. The communication device according to claim 18, wherein the determining means determines the received data based on the shift amount that maximizes the absolute value of the sum and the sum that maximizes the absolute value.

25. 19. The communication device according to claim 18, wherein said determining means determines a predetermined number of shift amounts based on an absolute value of said sum, and determines said received data based on said predetermined number of shift amounts.

26. the storage means further stores information indicating a second basic set including a first basic sequence to an N-th basic sequence, which are the sequence of the L complex numbers, and the first basic sequence to the N-th basic sequence of the second basic set satisfy the first condition; the storage means stores first timing information associated with the first basic set and second timing information associated with the second basic set; the determination means determines a first cyclic correlation between the nth received sequence received by the receiving means in accordance with the first timing information and the nth basic sequence of the first basic set, and determines first received data based on a total sum of correlation values ​​of the first cyclic correlation of the same shift amount obtained for the first to Nth received sequences; determines a second cyclic correlation between the nth received sequence received by the receiving means in accordance with the second timing information and the nth basic sequence of the second basic set, and determines second received data based on a total sum of correlation values ​​of the second cyclic correlation of the same shift amount obtained for the first to Nth received sequences; 19. The communication device according to claim 18, wherein the first basic set and the second basic set satisfy a second condition that a sum of correlation values ​​of periodic correlation between the nth basic sequence of the first basic set and the nth basic sequence of the second basic set at the same shift amount across the first basic sequence to the Nth basic sequence is 0 for all shift amounts used for receiving data.

27. the first received data and the second received data are data from different devices, 27. The communication device of claim 26, wherein the first timing information and the second timing information are the same information.

28. the first received data and the second received data are data from the same device, 27. The communication device of claim 26, wherein the first timing information and the second timing information are the same information.

29. the first received data and the second received data are data from different devices, 27. The communication device according to claim 26, wherein the first timing information and the second timing information are set so that reception timings of reception sequences received at the same frequency are different.

30. the first received data and the second received data are data from the same device, 27. The communication device according to claim 26, wherein the first timing information and the second timing information are set so that reception timings of reception sequences received at the same frequency are different.

31. 31. A computer-readable storage medium having stored thereon a computer program that, when executed by one or more processors of a device having one or more processors, causes the device to function as a communication device according to any one of claims 1 to 30.

32. A communication method by a communication device, comprising: determining a shift amount based on the transmitted data; cyclically shifting a first base sequence to an N-th base sequence (N is an integer equal to or greater than 2), which are sequences of L complex numbers (L is an integer equal to or greater than 2), by the shift amount to generate a first shifted sequence to an N-th shifted sequence; transmitting the first to Nth shifted sequences in accordance with timing information indicating sequence transmission timings; Including, a first condition is satisfied in which the first to Nth basic sequences satisfy a first condition that a sum of correlation values ​​of autocorrelation when a shift amount is 0 across the first to Nth basic sequences is different from 0, and a sum of correlation values ​​of autocorrelation when a shift amount different from 0 is used to transmit data across the first to Nth basic sequences is 0.

33. A communication method by a communication device, comprising: receiving a first received sequence to an N-th received sequence (N is an integer equal to or greater than 2), each of which is a sequence of L complex numbers (L is an integer equal to or greater than 2), in accordance with timing information indicating reception timings of the first received sequence to the N-th received sequence corresponding to the first basic sequence to the N-th basic sequence, each of which is an L complex number sequence (L is an integer equal to or greater than 2); determining a cyclic correlation between an n-th received sequence (n is an integer from 1 to N) and an n-th basic sequence, and determining received data based on a sum of correlation values ​​of the same shift amount of the cyclic correlation obtained for the first to N-th received sequences; Including, a first condition is satisfied in which the first to Nth basic sequences satisfy a first condition that a sum of correlation values ​​of autocorrelation when a shift amount is zero across the first to Nth basic sequences is different from zero, and a sum of correlation values ​​of autocorrelation when a shift amount different from zero is used for receiving data across the first to Nth basic sequences is zero.

34. A communication system including an access point and at least two communication devices, Each of the at least two communication devices a storage means for storing information indicating a basic set including a first basic sequence through an Nth basic sequence (N is an integer equal to or greater than 2), which are sequences of L complex numbers (L is an integer equal to or greater than 2); a shift means for determining a shift amount based on data to be transmitted to the access point, and for generating an n-th shifted sequence from a first shifted sequence by cyclically shifting an n-th basic sequence (n is an integer from 1 to N) by the shift amount to generate an n-th shifted sequence; a storage means for storing timing information indicating a transmission timing of the sequence; a transmitting means for transmitting the first to Nth shifted sequences in accordance with the timing information; Equipped with the first to Nth basic sequences satisfy a first condition that a sum of correlation values ​​of autocorrelation from the first to Nth basic sequences when a shift amount is zero is different from zero, and a sum of correlation values ​​of autocorrelation from the first to Nth basic sequences when a shift amount different from zero is used for data transmission is zero; a first communication device of the at least two communication devices stores a first basic set as the basic set and holds first timing information as the timing information; a second communication device of the at least two communication devices stores a second basic set as the basic set and holds second timing information as the timing information; the first basic set and the second basic set satisfy a second condition that a sum of correlation values ​​of periodic correlation between the nth basic sequence of the first basic set and the nth basic sequence of the second basic set at the same shift amount from the first basic sequence to the Nth basic sequence is 0 for all shift amounts used in data transmission; a transmission timing of the first shift sequence to the Nth shift sequence indicated by the first timing information is the same as a transmission timing of the first shift sequence to the Nth shift sequence indicated by the second timing information;

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