Communication control device, communication device, communication system, communication control program, and communication control method

Abstract

To provide a technique capable of identifying each node while suppressing power consumption even when a plurality of nodes with which optical space communication will be performed are located at a relatively long distance.SOLUTION: A communication control device 1 includes acquisition means 11 that acquires a code sequence reflected by one of a plurality of nodes, demodulation means 12 that demodulates the code sequence using one of spreading codes with a different pattern for each node, and identification means 13 that identifies a node that corresponds to the spreading code used for demodulation among the plurality of nodes. When the pulse width of an optical signal is shorter than the sequence length of the code sequence, the acquisition means acquires a first partial sequence that is part of the code sequence generated while the node is receiving one optical signal, acquires a second partial sequence that is part of the code sequence generated while the node is receiving another optical signal, and generates a code sequence by combining the second partial sequence after the first partial sequence.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present disclosure relates to a communication control device, a communication device, a communication system, a communication control program, and a communication control method. [Background technology]

[0002] Various techniques are known for capturing a node as a communication partner in optical space communications and making it ready for communication. One example of a technique for capturing a node is the acquisition and tracking method described in Patent Document 1. This acquisition and tracking method generates pulsed initial acquisition light during initial acquisition and transmits it from an optical antenna unit along a predetermined trajectory, generates and outputs a detection signal when reflected initial acquisition light, which is light reflected from the initial acquisition light, is detected, and transitions from initial acquisition to acquisition and tracking when the detection signal is output. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-156685 Summary of the Invention [Problem to be solved by the invention]

[0004] To establish communication with distant nodes, it is necessary to increase the output power of the optical signal. However, increasing the output power of the optical signal increases power consumption. Therefore, narrowing the pulse width of the optical signal increases the output power of the optical signal while suppressing the increase in power consumption. However, if the pulse width is narrowed, it becomes impossible to read the information that is reflected as light from each node and that is used to identify each node, which may make it impossible to identify each node.

[0005] The present disclosure has been made in consideration of the above-mentioned problems, and one exemplary purpose thereof is to provide a technology that can identify each node while reducing power consumption, even when multiple nodes that are partners in optical space communication are located at relatively long distances. [Means for solving the problem]

[0006] A communication control device according to an exemplary aspect of the present disclosure is a communication control device that identifies a plurality of nodes, wherein each of the plurality of nodes to be identified repeats a modulation operation to modulate received light into a code sequence using a spreading code having a pattern that differs for each node, and is configured to reflect at least a portion of the code sequence generated by at least a portion of the modulation operation performed while receiving a pulsed optical signal, and the communication control device includes: an acquisition means that acquires the code sequence reflected by one of the plurality of nodes; a demodulation means that demodulates the code sequence using one of the spreading codes having a pattern that differs for each node; and an identification means that identifies a node among the plurality of nodes corresponding to the spreading code used for the demodulation, wherein when the pulse width of the optical signal is shorter than the sequence length of the code sequence, the acquisition means acquires a first partial sequence that is a portion of the code sequence generated by the node while it is receiving one of the optical signals, acquires a second partial sequence that is a portion of the code sequence that follows the first partial sequence, generated by the node while it is receiving another of the optical signals, and generates the code sequence by combining the second partial sequence after the first partial sequence.

[0007] A communication device according to one exemplary aspect of the present disclosure comprises the above-described communication control device, an optical emitter that repeatedly emits the optical signal at a predetermined period, and an optical receiver that receives the code sequence, wherein the predetermined period is set to a time that is an integer multiple of the sequence length plus the pulse width of the optical signal.

[0008] A communication system according to an exemplary aspect of the present disclosure includes a plurality of nodes configured to repeatedly perform modulation operations to modulate received light into a code sequence using spreading codes of different patterns, and to reflect at least a portion of the code sequence generated by at least a portion of the modulation operations performed while receiving a pulsed optical signal, and the above-described communication control device or the above-described communication device.

[0009] A communication control program according to an exemplary aspect of the present disclosure is a communication control program for causing a computer to function as the above-mentioned communication control device, and causes the computer to function as the above-mentioned acquisition means, the above-mentioned demodulation means, and the above-mentioned identification means.

[0010] A communication control method according to an exemplary aspect of the present disclosure is a communication control method for identifying a plurality of nodes, wherein each of the plurality of nodes to be identified repeats a modulation operation for modulating received light into a code sequence using a spreading code having a pattern that differs for each node, and is configured to reflect at least a portion of the code sequence generated by at least a portion of the modulation operation performed while receiving a pulsed optical signal, and wherein a computer executes an acquisition step for acquiring the code sequence reflected by one of the plurality of nodes, a demodulation step for demodulating the code sequence using one of the spreading codes having a pattern that differs for each node, and an identification step for identifying a node among the plurality of nodes corresponding to the spreading code used for the demodulation, and when the pulse width of the optical signal is shorter than the sequence length of the code sequence, in the acquisition step, acquires a first partial sequence that is a portion of the code sequence generated by the node while receiving one of the optical signals, acquires a second partial sequence that is a portion of the code sequence that is a continuation of the first partial sequence, generated by the node while receiving another of the optical signals, and generates the code sequence by combining the second partial sequence after the first partial sequence. [Effects of the Invention]

[0011] According to an exemplary aspect of the present disclosure, even when multiple nodes with which optical space communication is performed are located at relatively long distances, it is possible to identify each node while suppressing power consumption. [Brief explanation of the drawings]

[0012] [Figure 1] 2 is a block diagram illustrating an example of a functional configuration of a communication control device according to a first exemplary embodiment of the present disclosure. FIG. [Figure 2]2 is a diagram showing an example of a node to be identified by the communication control device; FIG. [Figure 3] 10A and 10B are diagrams illustrating acquisition of a code sequence by the communication control device when the pulse width of an optical signal is equal to or greater than the sequence length of the code sequence. [Figure 4] 10A and 10B are diagrams illustrating acquisition of a code sequence by the communication control device when the pulse width of an optical signal is shorter than the sequence length of the code sequence. [Figure 5] FIG. 1 is a flow diagram illustrating an example of the flow of a communication control method according to the present disclosure. [Figure 6] FIG. 10 is a block diagram illustrating an example of a node to be identified by a communication control device according to a second exemplary embodiment of the present disclosure. [Figure 7] FIG. 2 is a diagram illustrating modulation of an optical signal performed by the node. [Figure 8] FIG. 2 is a block diagram showing the functional configuration of the communication control device. [Figure 9] 10A and 10B are diagrams illustrating an example of acquisition of a code sequence by the communication control device when the pulse width of an optical signal is shorter than the sequence length of the code sequence. [Figure 10] 10A and 10B are diagrams illustrating another example of acquisition of a code sequence by the communication control device when the pulse width of an optical signal is shorter than the sequence length of the code sequence. [Figure 11] FIG. 10 is a flow chart showing an example of the flow of a communication control method according to a second exemplary embodiment of the present disclosure. [Figure 12] FIG. 11 is a block diagram illustrating an example of a functional configuration of a communication device according to a third exemplary embodiment of the present disclosure. [Figure 13] FIG. 10 is a block diagram showing a schematic configuration of a communication system according to a fourth exemplary embodiment of the present disclosure. [Figure 14] FIG. 2 is a block diagram showing the hardware configuration of a computer that functions as a communication control device according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0013] The following are examples of embodiments of the present invention. However, the present invention is not limited to the exemplary embodiments shown below, and various modifications are possible within the scope of the claims. For example, embodiments obtained by appropriately combining the technical means employed in the exemplary embodiments shown below may also be included in the scope of the present invention. Furthermore, embodiments obtained by appropriately omitting some of the technical means employed in the exemplary embodiments shown below may also be included in the scope of the present invention. Furthermore, the effects mentioned in the exemplary embodiments shown below are examples of effects expected in the exemplary embodiments, and do not define the scope of the present invention. In other words, embodiments that do not exhibit the effects mentioned in the exemplary embodiments shown below may also be included in the scope of the present invention.

[0014] First Exemplary Embodiment A first exemplary embodiment, which is one example of an embodiment of the present invention, will be described in detail with reference to the drawings. This exemplary embodiment is the basic form of each exemplary embodiment described later. Note that the scope of application of each technical means employed in this exemplary embodiment is not limited to this exemplary embodiment. That is, each technical means employed in this exemplary embodiment can also be employed in other exemplary embodiments included in the present disclosure to the extent that no particular technical obstacles arise. Furthermore, each technical means shown in the drawings referred to in describing this exemplary embodiment can also be employed in other exemplary embodiments included in the present disclosure to the extent that no particular technical obstacles arise.

[0015] (Node 2 configuration) Before describing the communication control device 1, the configuration of a node 2 to be identified by the communication control device 1 will be described with reference to FIG. 2. The node 2 is a device that communicates with a communication device 3, which will be described later. The node 2 may be a device fixed at a predetermined location, or may be a mobile object (for example, a vehicle, a UAV (Unmanned Aerial Vehicle), etc.). Each of the multiple nodes 2 to be identified repeats a modulation operation to modulate received light into a code sequence using a spread code with a pattern that differs for each node. Each node 2 is configured to reflect at least a part of the code sequence (modulated optical signal) generated by at least a part of the modulation operation performed while receiving a pulsed optical signal.

[0016] (Configuration of communication control device 1) Next, the configuration of the communication control device 1 will be described with reference to Fig. 1. Fig. 1 is a block diagram showing the configuration of the communication control device 1. The communication control device 1 is a device that identifies multiple nodes 2. As shown in Fig. 1, the communication control device 1 includes an acquisition means 11, a demodulation means 12, and an identification means 13.

[0017] ·Acquisition method The acquiring means 11 acquires a code sequence reflected by one of the multiple nodes 2. When the pulse width of the optical signal is equal to or greater than the length of the code sequence, the entire code sequence arrives at the light receiving unit together, as shown in Figure 3. This allows the acquiring means 11 to acquire the code sequence all at once.

[0018] On the other hand, the pulse width of the optical signal may be shorter than the sequence length of the code sequence. In this case, the entire code sequence cannot reach the light receiving unit as a whole. In this case, the acquiring means 11 acquires a first partial sequence as shown in FIG. 4. The first partial sequence is a part of the code sequence generated while node 2 is receiving one optical signal. The acquiring means 11 also acquires a second partial sequence. The second partial sequence is a part of the code sequence that is a continuation of the first partial sequence and that is reflected while node 2 is receiving another optical signal. The acquiring means 11 then generates a code sequence by combining the second partial sequence with the acquired first partial sequence.

[0019] Demodulation means The demodulation means 12 demodulates the code sequence using one of the spreading codes with a pattern that differs for each node. If the demodulation uses the spreading code used for modulation by the node 2 that reflected the acquired code sequence, each code will gather at a predetermined pulse position to return to the original optical signal. On the other hand, if the demodulation uses a spreading code different from the spreading code used for modulation by the node 2 that reflected the acquired code sequence, each code will disperse and become noise.

[0020] ·Identification means The identification means 13 identifies, from among the multiple nodes 2, the node 2 that corresponds to the spreading code used for demodulation. In other words, it identifies the node 2 that has reflected the code sequence that has returned to the original optical signal through demodulation. Then, the identification means 13 outputs information about the identified node 2. The information is transmitted to, for example, the communication device 3 described below. This allows the communication device 3 to recognize the identified node as a communication destination.

[0021] (Effects of communication control device 1) The communication control device 1 described above is configured such that, when the pulse width of the optical signal is shorter than the sequence length of the code sequence, the acquiring means 11 acquires the first subsequence and the second subsequence. The communication control device 1 is also configured such that the acquiring means 11 generates the code sequence by combining the second subsequence with the first subsequence. That is, when the pulse width of the optical signal is shorter than the sequence length of the code sequence, the communication control device 1 acquires the code sequence in multiple parts. Therefore, the communication control device 1 according to this embodiment has the advantage of being able to identify each node 2 while suppressing power consumption, even when multiple nodes 2 with which to perform free-space optical communication are located at relatively long distances.

[0022] (Flow of communication control method) Next, the flow of the communication control method S1 will be described with reference to Fig. 5. Fig. 5 is a flow diagram showing the flow of the communication control method. The communication control method S1 is a method for identifying multiple nodes 2. Here, each of the multiple nodes 2 to be identified is the same as that described above in "Configuration of Node 2". As shown in Fig. 5, the communication control method S1 includes an acquisition step S11, a demodulation step S12, and an identification step S13. The acquisition step S11 includes a determination step S111, a collective acquisition step S112, a first portion acquisition step S113, a second portion acquisition step S114, and a combination step S115.

[0023] Acquisition steps In the initial acquisition step S11, a computer acquires a code sequence reflected by any one of a plurality of nodes. The computer used in the acquisition step S11 may be the communication control device 1 described above, or may be another computer. In the acquisition step S11, first, a determination step S111 is performed. If it is determined in the determination step S111 that the pulse width of the optical signal is equal to or greater than the sequence length of the code sequence (S111: YES), the process proceeds to a batch acquisition step S112. In the batch acquisition step S112, the computer acquires the code sequence all at once.

[0024] On the other hand, if it is determined in decision step S111 that the pulse width of the optical signal is shorter than the sequence length of the code sequence (S111: NO), the process proceeds to first portion acquisition step S113. In first portion acquisition step S113, the computer acquires a first subsequence. After acquiring the first subsequence, the process proceeds to second portion acquisition step S114. In second portion acquisition step S114, the computer acquires a second subsequence. Note that the order in which the computer acquires the subsequences does not matter. In other words, the first subsequence may be acquired after the second subsequence is acquired. After acquiring the first subsequence and the second subsequence, the process proceeds to combining step S115. In combining step S115, the computer generates a code sequence by combining the first subsequence with the second subsequence.

[0025] Demodulation step After the code sequence is acquired, the process proceeds to a demodulation step S12. In the demodulation step S12, the computer demodulates the code sequence using one of the spreading codes with different patterns for each node. The computer used in the demodulation step S12 may be the communication control device 1 or another computer.

[0026] Specific steps After the code sequence is demodulated, the process proceeds to identification step S13. In identification step S13, a computer identifies a node 2 corresponding to the spread code used for demodulation among the multiple nodes 2. The computer used in identification step S13 may be the communication control device 1 or another computer. Furthermore, the computer used in identification step S13 may be the same as or different from the computer used in the acquisition step S11 and demodulation step S12.

[0027] (Effects of communication control methods) As described above, the communication control method S1 employs a configuration in which, when the pulse width of the optical signal is shorter than the sequence length of the code sequence, the first subsequence and the second subsequence are acquired in the acquisition step S11. The communication control method S1 also employs a configuration in which, in the acquisition step S11, the code sequence is generated by concatenating the second subsequence after the first subsequence. That is, when the pulse width of the optical signal is shorter than the sequence length of the code sequence, the communication control method S1 acquires the code sequence in multiple parts. Therefore, the communication control method S1 according to this embodiment has the advantage of being able to identify each node 2 while suppressing power consumption, even when multiple nodes 2 with which optical space communication is performed are located at a relatively long distance.

[0028] Second Exemplary Embodiment A second exemplary embodiment, which is one example of an embodiment of the present invention, will be described in detail with reference to the drawings. Components having the same functions as those described in the above exemplary embodiment will be assigned the same reference numerals, and their description will be omitted as appropriate. The scope of application of each technical means employed in this exemplary embodiment is not limited to this exemplary embodiment. That is, each technical means employed in this exemplary embodiment can also be employed in other exemplary embodiments included in the present disclosure, to the extent that no particular technical obstacles arise. Furthermore, each technical means shown in each drawing referenced to explain this exemplary embodiment can also be employed in other exemplary embodiments included in the present disclosure, to the extent that no particular technical obstacles arise.

[0029] (Node 2 configuration) Before describing the communication control device 1A, the configuration of the node 2 to be identified by the communication control device 1A will be described with reference to Fig. 6. Fig. 6 is a block diagram showing the configuration of the node 2. Of the multiple nodes 2, Fig. 6 shows only node A and node B. As shown in Fig. 6, the node 2 according to this embodiment includes a modulating retroreflector (hereinafter, MRR 21), identification signal generating means 22, spreading code generating means 23, and signal input control means 24.

[0030] The MRR 21 repeats the modulation operation, and reflects, in the direction from which the optical signal came, at least a portion of the code sequence generated by at least a portion of the modulation operation performed while the MRR 21 is receiving the optical signal.

[0031] The identification signal generating means 22 generates a different identification signal for each node 2 .

[0032] The spreading code generating means 23 generates a spreading code corresponding to the identification signal. The spreading code used by the node 2 according to this embodiment is an optical orthogonal code. The spreading code may be a prime sequence code, an extended prime sequence code, or the like.

[0033] The signal input control means 24 controls the MRR 21 so that the MRR 21 performs modulation operations according to the spreading codes generated by the spreading code generation means 23. As described above, the identification signals are different for each node 2, and the optical orthogonal codes generated based on the different identification signals and the modulation operations of the MRR 21 according to the optical orthogonal codes are different for each node 2.

[0034] In the node 2 configured as described above, the MRR 21 repeats modulation operations (on-off keying (OOK)) under the control of the signal input control means 24. The MRR 21 of one node 2 (node ​​A) generates a code sequence with an on / off sequence pattern, for example, as shown in the upper part of FIG. 7. Meanwhile, the MRR 21 of another node (node ​​B) generates a code sequence with an on / off sequence pattern different from that of the first node 2, for example, as shown in the lower part of FIG. 7, because the signal input control means 24 references a different spreading code. Note that the nodes 2 are not synchronized. That is, each node 2 performs modulation operations independently. Therefore, the timing at which the modulation operation cycles of the nodes 2 are switched is usually not the same. Therefore, the subsequences corresponding to optical signals emitted at the same timing, acquired by the acquisition means 11A described later, do not necessarily correspond to the same part (for example, the beginning part) of the code sequence (see FIGS. 9 and 10).

[0035] (Configuration of communication control device 1A) Next, the configuration of the communication control device 1A will be described with reference to Fig. 8. Fig. 8 is a block diagram showing the configuration of the communication control device 1A. As shown in Fig. 8, the communication control device 1A according to this embodiment further includes an acquisition means 11A, a demodulation means 12A, a second demodulation means 12B, and a second identification means 13A in addition to the identification means 13 similar to that of the communication control device 1 according to the first exemplary embodiment. Note that the communication control device 1A may further include third to nth demodulation means and third to nth identification means.

[0036] ·Acquisition method The acquiring means 11A according to this embodiment acquires multiple code sequences reflected by multiple nodes. Furthermore, if the pulse width of the optical signal is shorter than the sequence length of the code sequence, the acquiring means 11A acquires a first subsequence and a second subsequence. Specifically, as shown in FIG. 9 , the acquiring means 11A acquires, as the first subsequence, a portion of the code sequence generated by a modulation operation performed while node 2 is receiving the first optical signal. Then, the acquiring means 11A acquires, as the second subsequence, a portion of the code sequence generated by a modulation operation performed while node 2 is receiving the second optical signal. Then, the acquiring means 11A generates a code sequence by concatenating the acquired first subsequence with the second subsequence. Note that if the pulse width of the optical signal is even shorter than the sequence length of the code sequence (the pulse width is 1 / m of the sequence length), the acquiring means 11A according to this embodiment further acquires third to m-th subsequences in addition to the first and second subsequences. The m-th subsequence is a portion of the code sequence that is a continuation of the (m-1)th subsequence that was reflected while node 2 was receiving the optical signal. In this case, the acquiring means 11A generates a code sequence by combining the acquired first to m-th partial sequences.

[0037] Furthermore, the communication control device 1 and each node 2 are not synchronized. Therefore, the optical signal does not necessarily arrive at node 2 at the same time that the modulation operation of node 2 switches to the next cycle (the first reflected subsequence does not necessarily start from the beginning). In this case, as shown in FIG. 10, the acquiring means 11A acquires the intermediate portions of the code sequence generated by the modulation operation performed while node 2 is receiving the first, second, etc. optical signals as the mth, m+1th, etc. subsequences. Because node 2 repeats the modulation operation, the cycle of node 2's modulation operation switches at a certain timing while receiving (or simultaneously with) the optical signal. The portion including the beginning of the code sequence generated at this timing is acquired as the first subsequence. Then, the acquiring means 11A generates a code sequence by combining each acquired subsequence in order, starting from the first subsequence.

[0038] Demodulation means The demodulation means 12A demodulates the multiple code sequences using one of the spreading codes with a different pattern for each node. As a result, only the code sequences modulated with the same spreading code as the one used for demodulation gather at predetermined pulse positions to form the original optical signal. On the other hand, the remaining code sequences modulated with spreading codes different from the one used for demodulation disperse the codes and become noise.

[0039] Second demodulation means, nth demodulation means The second demodulation means 12B demodulates each of the code sequences using a spreading code from among a plurality of patterns that is different from the one used by the demodulation means 12. As a result, a code sequence different from the code sequence demodulated into the optical signal by the demodulation means 12 is demodulated into the optical signal. The nth demodulation means demodulates each of the code sequences using a spreading code from among a plurality of patterns that is different from the ones used by the demodulation means 12 to the (n-1)th demodulation means.

[0040] Note that if the distances between the transmission point and each node 2 are different, a near-far problem specific to code division multiple access (CDMA) communication occurs. That is, a signal arriving from a distant node 2 is interfered with by a signal generated by a closer node 2. For this reason, the demodulation means and the second to nth demodulation means according to this embodiment demodulate not only the code sequence of the desired (distant) node 2 but also the code sequences of the other (nearer) nodes 2 in parallel by referring to the spreading codes of the other nodes 2. Then, the demodulation means and the second to nth demodulation means remove the influence of interference by subtracting the code sequences of the other nodes 2 from the code sequence of the desired node 2.

[0041] In addition, if node 2 moves, a difference occurs in the timing of reflection. If the ON / OFF frequency for pointing is 10 MHz, 1 chip time of the spread signal is 10 -7 s = 0.1 μs. In other words, node 2 moving in the direction of the transmission point at 100 km / h will approach the transmission point by 28 mm (56 mm round trip) before 1 ms has passed. The time it takes light to travel this distance round trip is approximately 0.2 ns. However, this round trip time is sufficiently short compared to the 0.1 μs of one chip, so interference caused by the movement of node 2 can be ignored.

[0042] ·Second identification means, nth identification means The second identifying means 13A identifies the node 2 corresponding to the spreading code used for demodulation by the second demodulation means 12B among the plurality of nodes 2. This identifies a node 2 different from the node 2 identified by the identifying means 13. The nth identifying means identifies the node 2 corresponding to the spreading code used for demodulation by the nth demodulation means.

[0043] (Effects of communication control device 1A) The communication control device 1A described above can achieve the same effect as the communication control device 1 according to the first exemplary embodiment. That is, the communication control device 1A can achieve the effect of identifying each node 2 while suppressing power consumption, even when multiple nodes 2 with which optical space communication is performed are located at a relatively long distance. Furthermore, the communication control device 1A described above employs a configuration in which the second demodulation means 12B demodulates each code sequence using a spreading code different from that used by the demodulation means 12. Furthermore, the communication control device 1A employs a configuration in which the second identification means 13A identifies, among the multiple nodes 2, the node 2 corresponding to the spreading code used for demodulation by the second demodulation means 12B. Therefore, the communication control device 1A can achieve the effect of establishing communication with multiple nodes 2 in parallel.

[0044] (Flow of communication control method) Next, the flow of the communication control method S1A will be described with reference to FIG. 11. FIG. 11 is a flow diagram showing the flow of the communication control method. The communication control method S1A is a method for identifying multiple nodes 2. Here, each of the multiple nodes 2 to be identified is the same as the node 2 identified by the communication control device 1 according to the first exemplary embodiment. As shown in FIG. 11, the communication control method S1A includes an acquisition step S11A, a demodulation step S12A, a second demodulation step S12B, and a second identification step S13A, in addition to the identification step S13 similar to that of the communication control method S1 according to the first exemplary embodiment. Note that the communication control method S1A may further include third to n-th demodulation steps and third to n-th identification steps. Furthermore, the acquisition step S11 may further include third to n-th portion acquisition steps in addition to the first portion acquisition step S113 and the second portion acquisition step S114.

[0045] Acquisition steps In the initial acquisition step S11A, the computer acquires multiple code sequences reflected by multiple nodes. If the pulse width of the optical signal is shorter than the sequence length of the code sequence, a first subsequence and a second subsequence are acquired in a first portion acquisition step S113 and a second portion acquisition step S114. Note that in the acquisition step S11A according to this embodiment, if the pulse width of the optical signal is even shorter than the sequence length of the code sequence (the pulse width is 1 / m of the sequence length), the process proceeds to an additional portion acquisition step S116 after the second portion acquisition step S114. In the additional portion acquisition step S116, the computer further acquires third to mth subsequences. In this case, a code sequence is generated by combining the acquired first to mth subsequences in a combining step S115.

[0046] Demodulation step After acquiring the plurality of code sequences, the process proceeds to a demodulation step S12A, in which the computer demodulates the plurality of code sequences using one of the spreading codes with a different pattern for each node.

[0047] Second demodulation step After acquiring the code sequences, the process proceeds to a second demodulation step S12B. In the second demodulation step S12B, the computer demodulates each of the code sequences using a spreading code different from the one used in the demodulation step S12, among a plurality of spreading code patterns. As a result, a code sequence different from the code sequence demodulated into the optical signal in the demodulation step S12 is demodulated into the optical signal. Note that the second demodulation step S12B may be performed before the demodulation step S12, or may be performed in parallel with the demodulation step S12.

[0048] Second identification step After demodulating the code sequence, the process proceeds to a second identification step S13A. In the second identification step S13A, the computer identifies, from among the multiple nodes 2, a node 2 that corresponds to the spreading code used for demodulation in the second demodulation step S12B. This identifies a node 2 that is different from the node 2 identified in the identification step S13. Note that the second identification step S13A may be performed before the identification step S13, or may be performed in parallel with the identification step S13.

[0049] (Effects of communication control methods) The communication control method S1A described above provides the same effect as the communication control method S1 according to the first exemplary embodiment. That is, the communication control method S1A provides the effect of being able to identify each node 2 while suppressing power consumption, even when multiple nodes 2 with which optical space communication is performed are located at a relatively long distance. Furthermore, the communication control method S1A described above employs a configuration in which, in the second demodulation step S12B, each code sequence is demodulated using a spreading code different from that used by the demodulation means 12. Furthermore, the communication control method S1A employs a configuration in which, in the second identification step S13A, a node 2 among the multiple nodes 2 is identified that corresponds to the spreading code used for demodulation in the second demodulation step S12B. Therefore, the communication control method S1A provides the effect of being able to establish communication with multiple nodes 2 in parallel.

[0050] Third Exemplary Embodiment A third exemplary embodiment, which is an example of an embodiment of the present invention, will be described in detail with reference to the drawings. Components having the same functions as those described in the above exemplary embodiment will be assigned the same reference numerals, and their description will be omitted as appropriate. The scope of application of each technical means employed in this exemplary embodiment is not limited to this exemplary embodiment. That is, each technical means employed in this exemplary embodiment can also be employed in other exemplary embodiments included in the present disclosure, to the extent that no particular technical obstacles arise. Furthermore, each technical means shown in each drawing referenced to explain this exemplary embodiment can also be employed in other exemplary embodiments included in the present disclosure, to the extent that no particular technical obstacles arise.

[0051] (Configuration of communication device 3) The configuration of the communication device 3 will be described with reference to Fig. 12. Fig. 12 is a block diagram showing the configuration of the communication device 3. As shown in Fig. 12, the communication device 3 according to this embodiment further includes a light emitting unit 14, a light receiving unit 15, pulse generation control means 16, and transmission direction control means 17 in addition to the communication control device 1 similar to that of the first exemplary embodiment or the communication control device 1A similar to that of the second exemplary embodiment.

[0052] Light-emitting part The light emitting unit 14 repeatedly emits an optical signal at a predetermined period. The light emitting unit 14 according to this embodiment emits a first optical signal at an arbitrary timing. Then, as shown in FIG. 9, the light emitting unit 14 emits a second optical signal after a predetermined period Ta has elapsed since the emission of the first optical signal. The predetermined period Ta is set to a time obtained by adding a pulse width Tp of the optical signal to a time that is an integer multiple Na of the sequence length TL of the code sequence. Similar to the second optical signal, the light emitting unit 14 emits an nth (n=3··) optical signal after a predetermined period Ta has elapsed since the emission of the (n-1)th optical signal. Furthermore, the light emitting unit 14 repeatedly emits the optical signal a number of times (Np times) that is an integer multiple of the number obtained by dividing the sequence length TL of the code sequence by the pulse width Tp of the optical signal. If the sequence length is not divisible by the pulse width, the light emitting unit 14 sets the number of times (Np times) to an integer multiple of the number obtained by rounding off the number obtained by dividing the sequence length by the pulse width of the optical signal.

[0053] Note that the communication control device 1 and each node 2 are not synchronized. Therefore, the optical signal does not necessarily arrive at node 2 at the same time that the modulation operation of node 2 switches to the next cycle (the first reflected subsequence does not necessarily start from the beginning). For this reason, as shown in FIGS. 9 and 10, the light-emitting unit 14 according to this embodiment repeatedly emits an optical signal Np×n times (n is an integer equal to or greater than 2). As a result, even if the optical signal arrives at node 2 during modulation operation in one cycle and the subsequence reflected first from node 2 is partway through the code sequence, the subsequence from the beginning to the middle of the code sequence will be reflected during modulation operation in the next cycle. Therefore, the acquiring means can reliably acquire the entire code sequence.

[0054] Pulse generation control means Returning to the explanation of Fig. 12, the pulse generation control means 16 controls the light emitting unit 14 so that the light emitting unit 14 emits an optical signal with a preset pulse width. The pulse generation control means 16 is capable of adjusting the intensity of the optical signal in response to a setting operation by the user. The pulse generation control means 16 is also capable of adjusting the pulse width of the optical signal in response to a setting operation by the user.

[0055] Transmission direction control means The transmission direction control means 17 controls the light emitting unit 14 so that the light emitting unit 14 faces a desired direction (so that an optical signal is emitted in a desired direction) in response to, for example, an operation by a user. Furthermore, the transmission direction control means 17 controls the light emitting unit 14 so that the light emitting unit 14 faces the direction of the identified node based on information about the node identified by the communication control device 1, 1A.

[0056] ·Light receiving part The light receiving unit 15 receives a plurality of code sequences reflected from each node 2 .

[0057] (Effect of communication device 3) The communication device 3 described above can achieve the same effect as the communication control device 1 according to the first exemplary embodiment. That is, the communication device 3 can achieve the effect of identifying each node 2 while suppressing power consumption, even when multiple nodes 2 with which to perform optical space communication are located at a relatively long distance. Furthermore, the communication device 3 described above employs a configuration including a light-emitting unit and a light-receiving unit (the communication control device and the means for actually performing communication are integrated). Therefore, the communication device 3 can achieve the effect of easily identifying the node 2 without the need to separately provide a device for emitting an optical signal and a device for receiving a code sequence in addition to the communication control devices 1 and 1A.

[0058] Fourth Exemplary Embodiment A fourth exemplary embodiment, which is an example of an embodiment of the present invention, will be described in detail with reference to the drawings. Components having the same functions as those described in the above exemplary embodiment will be assigned the same reference numerals, and their description will be omitted as appropriate. The scope of application of each technical means employed in this exemplary embodiment is not limited to this exemplary embodiment. That is, each technical means employed in this exemplary embodiment can also be employed in other exemplary embodiments included in the present disclosure, to the extent that no particular technical obstacles arise. Furthermore, each technical means shown in each drawing referenced to explain this exemplary embodiment can also be employed in other exemplary embodiments included in the present disclosure, to the extent that no particular technical obstacles arise.

[0059] (Communication System Configuration) The configuration of the communication system 100 will be described with reference to Fig. 13. Fig. 13 is a block diagram showing the configuration of the communication system 100. As shown in Fig. 13, the communication system 100 according to this embodiment includes a plurality of nodes 2... described in the first and second exemplary embodiments, and a communication device 3 similar to that in the third exemplary embodiment. Note that the communication system 100 may include communication control devices 1, 1A similar to those in the first and second exemplary embodiments, instead of the communication device 3.

[0060] Communication equipment The communication device 3 communicates with the node 2 identified by the communication control device 1, 1A. The communication device 3 communicates with the node 2 identified by the communication control device 1 by free space optics (FSO).

[0061] (Effects of communication systems) The communication system 100 described above employs a configuration including either the communication control device 1 or 1A according to the first or second exemplary embodiment. That is, when the pulse width of an optical signal is shorter than the sequence length of the code sequence, the communication control device 1 or 1A acquires the code sequence by dividing it into multiple parts. Therefore, the communication system 100 according to this embodiment has the advantage that it is possible to identify each node 2 while suppressing power consumption, even when multiple nodes 2 with which optical space communication is performed are located at a relatively long distance.

[0062] [Software implementation example] Some or all of the functions of the communication control devices 1, 1A (hereinafter also referred to as "each of the above devices") may be realized by hardware such as an integrated circuit (IC chip), or by software.

[0063] In the latter case, each of the above devices is realized by, for example, a computer that executes instructions of a program, which is software that realizes each function. An example of such a computer (hereinafter referred to as a computer CP) is shown in Figure 14. Figure 14 is a block diagram showing the hardware configuration of the computer CP that functions as each of the above devices.

[0064] The computer CP includes at least one processor C1 and at least one memory C2. The memory C2 stores a program P for causing the computer C to operate as each of the above-mentioned devices. In the computer C, the processor C1 reads and executes the program P from the memory C2, thereby realizing the functions of each of the above-mentioned devices.

[0065] The processor C1 may be, for example, a central processing unit (CPU), a graphic processing unit (GPU), a digital signal processor (DSP), a micro processing unit (MPU), a floating point number processing unit (FPU), a physics processing unit (PPU), a tensor processing unit (TPU), a quantum processor, a microcontroller, or a combination thereof. The memory C2 may be, for example, a flash memory, a hard disk drive (HDD), a solid state drive (SSD), or a combination thereof.

[0066] The computer CP may further include a RAM (Random Access Memory) for expanding the program P during execution and for temporarily storing various data. The computer CP may also include a communication interface for transmitting and receiving data to and from other devices. The computer CP may also include an input / output interface for connecting input / output devices such as a keyboard, mouse, display, and printer.

[0067] The program P can also be recorded on a non-transitory tangible recording medium M that can be read by the computer CP. Such a recording medium M can be, for example, a tape, a disk, a card, a semiconductor memory, or a programmable logic circuit. The computer CP can acquire the program P via such a recording medium M. The program P can also be transmitted via a transmission medium. Such a transmission medium can be, for example, a communication network or broadcast waves. The computer CP can also acquire the program P via such a transmission medium.

[0068] [Appendix 1] This disclosure includes the techniques described in the following appendices. However, the present invention is not limited to the techniques described in the following appendices, and various modifications are possible within the scope of the claims.

[0069] (Appendix 1) A communication control device for identifying a plurality of nodes, each of the plurality of nodes to be identified repeats a modulation operation for modulating received light into a code sequence using a spread code having a pattern that differs for each node, and is configured to reflect at least a part of the code sequence generated by at least a part of the modulation operation performed while receiving a pulsed optical signal; an acquisition means for acquiring a code sequence reflected by any one of the plurality of nodes; demodulation means for demodulating the code sequence using any one of spreading codes having a different pattern for each node; a specifying means for specifying a node corresponding to the spreading code used for the demodulation among the plurality of nodes; Equipped with When the pulse width of the optical signal is shorter than the sequence length of the code sequence, the acquiring means acquiring a first subsequence that is a part of the code sequence generated while the node is receiving one of the optical signals; obtaining a second subsequence, which is a part of the code sequence that is a continuation of the first subsequence and which is generated while the node is receiving another of the optical signals; generating the code sequence by concatenating the first subsequence followed by the second subsequence; Communications control device.

[0070] (Appendix 2) a communication control device according to Supplementary Note 1; a light emitting unit that repeatedly emits the optical signal at a predetermined cycle; a light receiving unit for receiving the code sequence; Furthermore, the predetermined period is set to a time obtained by adding the pulse width of the optical signal to a time that is an integer multiple of the sequence length. Communication equipment.

[0071] (Appendix 3) the light emitting unit repeatedly emits the optical signal a number of times equal to an integer multiple of a number obtained by dividing a sequence length of the code sequence by a pulse width of the optical signal; 3. The communications device of claim 2.

[0072] (Appendix 4) the acquiring means acquires a plurality of code sequences reflected by the plurality of nodes, the demodulation means demodulates the plurality of code sequences using any one of spreading codes having a pattern that differs for each of the nodes; a second demodulation means for demodulating each of the code sequences using a spreading code different from that used by the demodulation means, among a plurality of patterns of the spreading codes; a second identification means for identifying the node corresponding to the spreading code used for the demodulation by the second demodulation means, among the plurality of nodes; Further provided with 4. A communication control device according to any one of Supplementary Note 1 to Supplementary Note 3.

[0073] (Appendix 5) the spreading code is an optical orthogonal code; 5. A communication control device according to any one of Supplementary Note 1 to Supplementary Note 4.

[0074] (Appendix 6) a plurality of nodes configured to repeat a modulation operation for modulating received light into a code sequence using spreading codes of different patterns, and to reflect at least a portion of the code sequence generated by at least a portion of the modulation operation performed while receiving a pulsed optical signal; A communication control device according to any one of Supplementary Note 1, 4, and 5, or a communication device according to Supplementary Note 2 or 3; Equipped with Communication system.

[0075] (Appendix 7) A communication control program for causing a computer to function as the communication control device according to claim 1, a communication control program for causing a computer to function as the acquiring means, the demodulating means, and the identifying means;

[0076] (Appendix 8) A communication control method for identifying a plurality of nodes, comprising: each of the plurality of nodes to be identified repeats a modulation operation for modulating received light into a code sequence using a spread code having a pattern that differs for each node, and is configured to reflect at least a part of the code sequence generated by at least a part of the modulation operation performed while receiving a pulsed optical signal; The computer an acquisition step of acquiring a code sequence reflected by any of the plurality of nodes; a demodulation step of demodulating the code sequence using any one of spreading codes having a pattern that differs for each of the nodes; a step of identifying a node corresponding to the spreading code used for the demodulation among the plurality of nodes; Run When the pulse width of the optical signal is shorter than the sequence length of the code sequence, in the acquiring step, acquiring a first subsequence that is a part of the code sequence generated while the node is receiving one of the optical signals; obtaining a second subsequence, which is a part of the code sequence that is a continuation of the first subsequence and which is generated while the node is receiving another of the optical signals; generating the code sequence by concatenating the first subsequence followed by the second subsequence; Communication control method.

[0077] (Appendix 9) The computer a light emitting unit that repeatedly emits the optical signal at a predetermined cycle; a light receiving unit for receiving the code sequence; Furthermore, the predetermined period is set to a time obtained by adding the pulse width of the optical signal to a time that is an integer multiple of the sequence length. 9. A communication control method according to claim 8.

[0078] (Appendix 10) the light emitting unit repeatedly emits the optical signal a number of times equal to an integer multiple of a number obtained by dividing a sequence length of the code sequence by a pulse width of the optical signal; 10. The communication control method according to claim 9.

[0079] (Appendix 11) In the acquiring step, the plurality of nodes acquires a plurality of reflected code sequences, In the demodulating step, the plurality of code sequences are demodulated using any one of spreading codes having a pattern that differs for each of the nodes; a second demodulation step of demodulating each of the code sequences using a spreading code different from that used in the demodulation step, among a plurality of patterns of the spreading codes; a second identifying step of identifying the node corresponding to the spreading code used for the demodulation in the second demodulation step among the plurality of nodes; further comprising: 11. A communication control method according to any one of Supplementary Note 8 to Supplementary Note 10.

[0080] (Appendix 12) the spreading code is an optical orthogonal code; 9. A communication control method according to claim 8.

[0081] [Appendix 2] This disclosure includes the techniques described in the following appendices. However, the present invention is not limited to the techniques described in the following appendices, and various modifications are possible within the scope of the claims.

[0082] (Appendix 1) at least one processor; each of the plurality of nodes to be identified repeats a modulation operation for modulating received light into a code sequence using a spread code having a pattern that differs for each node, and is configured to reflect at least a part of the code sequence generated by at least a part of the modulation operation performed while receiving a pulsed optical signal; The at least one processor: an acquisition process of acquiring a code sequence reflected by any one of the plurality of nodes; a demodulation process of demodulating the code sequence using one of spread codes having a pattern that differs for each node; a process of identifying a node corresponding to the spreading code used for the demodulation among the plurality of nodes; Run When the pulse width of the optical signal is shorter than the sequence length of the code sequence, in the acquisition process, the at least one processor: acquiring a first subsequence that is a part of the code sequence generated while the node is receiving one of the optical signals; obtaining a second subsequence, which is a part of the code sequence that is a continuation of the first subsequence and which is generated while the node is receiving another of the optical signals; generating the code sequence by concatenating the first subsequence followed by the second subsequence; Communications control device. The communication control device may further include a memory, and the memory may store a program for causing the at least one processor to execute each of the processes.

[0083] (Appendix 2) a communication control device according to Supplementary Note 1; a light emitting unit that repeatedly emits the optical signal at a predetermined cycle; a light receiving unit for receiving the code sequence; Furthermore, the predetermined period is set to a time obtained by adding the pulse width of the optical signal to a time that is an integer multiple of the sequence length. Communication equipment.

[0084] (Appendix 3) the light emitting unit repeatedly emits the optical signal a number of times equal to an integer multiple of a number obtained by dividing a sequence length of the code sequence by a pulse width of the optical signal; 3. The communications device of claim 2.

[0085] (Appendix 4) The at least one processor: In the acquisition process, the plurality of nodes acquires a plurality of reflected code sequences, In the demodulation process, the plurality of code sequences are demodulated using any one of spreading codes having a pattern that differs for each of the nodes; a second demodulation process for demodulating each of the code sequences using a spreading code different from that used in the demodulation process, among a plurality of patterns of the spreading codes; a second identification process for identifying the node corresponding to the spreading code used for the demodulation in the second demodulation process among the plurality of nodes; Further implementation of 2. The communication control device of claim 1.

[0086] (Appendix 5) the spreading code is an optical orthogonal code; 2. The communication control device of claim 1. [Explanation of symbols]

[0087] 100 Communication Systems 1, 1A communication control device 11, 11A Acquisition method 12, 12A Demodulation means 12B Second demodulation means 13 Specific means 13A Second identification means 14 Light-emitting part 15 Light receiving part 16 Pulse generation control means 17 Transmission direction control means 2 nodes 21 MRR 22 Identification signal generating means 23 Spreading code generating means 24 Signal input control means 3. Communications equipment C1 processor C2 Memory S1, S1A communication control method S11, S11A acquisition steps S111 Decision step S112 Bulk Acquisition Step S113 First part acquisition step S114 Second part acquisition step S115 Binding step S116 Additional part acquisition step S12, S12A demodulation steps S12B Second demodulation step S13 Specific step S13A Second Identification Step Ta predetermined period Tp pulse width TL sequence length

Claims

1. A communication control device for identifying a plurality of nodes, each of the plurality of nodes to be identified repeats a modulation operation for modulating received light into a code sequence using a spread code having a pattern that differs for each node, and is configured to reflect at least a part of the code sequence generated by at least a part of the modulation operation performed while receiving a pulsed optical signal; an acquisition means for acquiring a code sequence reflected by any one of the plurality of nodes; demodulation means for demodulating the code sequence using any one of spreading codes having a different pattern for each node; a specifying means for specifying a node corresponding to the spreading code used for the demodulation among the plurality of nodes; Equipped with When the pulse width of the optical signal is shorter than the sequence length of the code sequence, the acquiring means acquiring a first subsequence that is a part of the code sequence generated while the node is receiving one of the optical signals; obtaining a second subsequence, which is a part of the code sequence that is a continuation of the first subsequence and which is generated while the node is receiving another of the optical signals; generating the code sequence by concatenating the first subsequence followed by the second subsequence; Communications control device.

2. The communication control device according to claim 1 ; a light emitting unit that repeatedly emits the optical signal at a predetermined cycle; a light receiving unit for receiving the code sequence; Equipped with the predetermined period is set to a time obtained by adding the pulse width of the optical signal to a time that is an integer multiple of the sequence length. Communication equipment.

3. the light emitting unit repeatedly emits the optical signal a number of times equal to an integer multiple of a number obtained by dividing a sequence length of the code sequence by a pulse width of the optical signal; The communication device according to claim 2 .

4. the acquiring means acquires a plurality of code sequences reflected by the plurality of nodes, the demodulation means demodulates the plurality of code sequences using any one of spreading codes having a pattern that differs for each of the nodes; a second demodulation means for demodulating each of the code sequences using a spreading code different from that used by the demodulation means, among a plurality of patterns of the spreading codes; a second identification means for identifying the node corresponding to the spreading code used for the demodulation by the second demodulation means, among the plurality of nodes; Further provided with The communication control device according to claim 1 .

5. the spreading code is an optical orthogonal code; The communication control device according to claim 1 .

6. a plurality of nodes configured to repeat a modulation operation for modulating received light into a code sequence using spreading codes of different patterns, and to reflect at least a portion of the code sequence generated by at least a portion of the modulation operation performed while receiving a pulsed optical signal; A communication control device according to any one of claims 1, 4, and 5, or a communication device according to claim 2 or 3; Equipped with Communication system.

7. A communication control program for causing a computer to function as the communication control device according to claim 1, a communication control program for causing a computer to function as the acquiring means, the demodulating means, and the identifying means;

8. A communication control method for identifying a plurality of nodes, comprising: each of the plurality of nodes to be identified repeats a modulation operation for modulating received light into a code sequence using a spread code having a pattern that differs for each node, and is configured to reflect at least a part of the code sequence generated by at least a part of the modulation operation performed while receiving a pulsed optical signal; The computer an acquisition step of acquiring a code sequence reflected by any of the plurality of nodes; a demodulation step of demodulating the code sequence using any one of spreading codes having a pattern that differs for each of the nodes; a step of identifying a node corresponding to the spreading code used for the demodulation among the plurality of nodes; Run When the pulse width of the optical signal is shorter than the sequence length of the code sequence, in the acquiring step, acquiring a first subsequence that is a part of the code sequence generated while the node is receiving one of the optical signals; obtaining a second subsequence, which is a part of the code sequence that is a continuation of the first subsequence and which is generated while the node is receiving another of the optical signals; generating the code sequence by concatenating the first subsequence followed by the second subsequence; Communication control method.

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