Wireless device, method for generating frequency-hopping pattern, computer program, and wireless communication system

Abstract

The purpose of the present invention is to provide a wireless communication device that, when allocating a frequency-hopping pattern to each of nearly wireless apparatuses that use the same frequency band, defines a frequency-hopping pattern with which the number of times that mutual interference occurs in succession does not exceed a given upper-limit count. Therefore, one of the typical wireless devices according to the present invention comprises a variation amount calculation unit that calculates the amount of variation in a frequency channel of the frequency-hopping pattern of frequency hopping that is repeatedly executed by a plurality of wireless devices, and a hopping pattern calculation unit that calculates the frequency-hopping pattern on the basis of the amount of variation in the frequency channel, the hopping pattern calculation unit calculating the frequency-hopping pattern such that the same frequency channel does not coincide among different wireless devices in succession, even for the same amount of variation.

Description

Radio device, frequency hopping pattern generation method, computer program, and radio communication system

[0001] The present invention relates to a radio device, a method for generating a frequency hopping pattern, a computer program, and a radio communication system.

[0002] Wireless communication devices communicate using frequency hopping, which switches frequencies at high speed, to prevent mutual interference between devices communicating within the same frequency band. If communication timing synchronization can be established between wireless communication devices, mutual interference can be suppressed by defining a frequency hopping pattern that selects different frequencies at the same timing. If communication timing synchronization cannot be established between wireless communication devices, mutual interference can be reduced probabilistically by defining a random frequency hopping pattern rather than a frequency hopping pattern that completely avoids mutual interference.

[0003] For example, Patent Document 1 discloses the following wireless device: "The frequency band f in slot n is calculated as {(n-1) mod F} + 1 = f (where A mod B is the remainder when A is divided by B), the frequency range [n, f] used in each slot is changed from n=1 to n=8 to generate pattern 1, the frequency band in slot 1 is calculated as 1, the frequency band in slot n-1 is calculated as f(n-1), and the frequency band f in slot n is calculated as [{(fn-1-1) + k} mod F] + 1 = f, and only if the frequency band f calculated as the frequency band to be assigned to slot n has already been assigned to slot 1 to slot n-1, frequency band f+1 is reallocated as frequency band f in slot n, and the frequency range [n, f] used in each slot is changed from n=2 to n=8 to generate patterns 2 to 7 by changing the pattern from k=2 to k=7."

[0004] Japanese Patent Application Laid-Open No. 2000-151468

[0005] However, even if random hopping patterns are defined in advance so that hopping patterns with high mutual similarity are not generated, there is a problem that hopping patterns with high mutual similarity will be selected probabilistically.

[0006] Therefore, the present invention provides a wireless communication device that defines a frequency hopping pattern that does not exceed a certain upper limit for the number of consecutive occurrences of mutual interference when assigning frequency hopping patterns to each of nearby wireless devices that use the same frequency band.

[0007] In order to solve the above problem, one representative wireless device of the present invention includes a change amount calculation unit that calculates a change amount of a frequency channel in a frequency hopping pattern of frequency hopping that is repeatedly performed by multiple wireless devices, and a hopping pattern calculation unit that calculates the frequency hopping pattern based on the change amount of the frequency channel, and the hopping pattern calculation unit calculates a frequency hopping pattern that does not result in the same frequency channel being used consecutively between different wireless devices even if the change amount is the same.

[0008] According to the present invention, it is possible to provide a wireless communication device that defines a frequency hopping pattern that does not exceed a certain upper limit number of times that mutual interference occurs consecutively when assigning a frequency hopping pattern to each of nearby wireless devices that use the same frequency band.

[0009] Fig. 1 is a diagram showing an example of the configuration of a wireless communication system. Fig. 2 is a diagram showing an example of the configuration of a wireless control device. Fig. 3 is a diagram showing the relationship between time division channels and frequency hopping pattern sequences. Fig. 4 is a diagram showing an example of a frequency hopping pattern sequence and a hop change amount arrangement. Fig. 5 is a diagram showing an example of a frequency hopping pattern sequence and a hop change amount arrangement.

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to these examples. In addition, in the description of the drawings, identical parts are denoted by the same reference numerals. When there are multiple components having the same or similar functions, they may be described by using the same reference numerals with different subscripts. Furthermore, when it is not necessary to distinguish between these multiple components, the subscripts may be omitted. The position, size, shape, range, etc. of each component shown in the drawings may not represent the actual position, size, shape, range, etc., in order to facilitate understanding of the invention. Therefore, the present invention is not necessarily limited to the position, size, shape, range, etc. disclosed in the drawings.

[0011] [First Embodiment] First, a wireless communication system 100 according to the first embodiment will be described with reference to Figures 1 and 2. Figure 1 is a diagram showing an example of the configuration of the wireless communication system 100. Figure 2 is a diagram showing an example of the configuration of a wireless control device 11. The wireless communication system 100 is a telecommunications system that mainly uses radio waves. The wireless communication system 100 mainly includes the wireless control device 11, a first data transmission device 12, a backhaul network 13, a terrestrial wireless device 14, a mobile wireless device 15, and a second data transmission device 16.

[0012] <Radio Control Device> The radio control device 11 performs overall control of the terrestrial radio device 14. The radio control device 11 is connected to the backhaul network 13, and communicates with the first data transmission device 12, the backhaul network 13, and the terrestrial radio device 14 via the backhaul network 13. The radio control device 11 mainly includes a hopping pattern calculation unit 111, an initial value calculation unit 112, and a change amount calculation unit 113.

[0013] The hopping pattern calculation unit 111 calculates a frequency hopping pattern for communication between the terrestrial radio device 14 and the mobile radio device 15. Here, the frequency hopping pattern refers to a frequency hopping pattern that is repeatedly executed by multiple radio devices. The hopping pattern calculation unit 111 calculates the frequency hopping pattern based on the initial value of the frequency hopping pattern calculated by the initial value calculation unit 112 and the amount of change in the frequency channel of the frequency hopping pattern calculated by the change amount calculation unit 113.

[0014] In this embodiment, the hopping pattern calculation unit 111, initial value calculation unit 112, and change amount calculation unit 113 are all included in the radio control device 11, but they may also be included elsewhere. For example, the hopping pattern calculation unit 111, initial value calculation unit 112, and change amount calculation unit 113 may all be included in the terrestrial radio device 14. For example, the hopping pattern calculation unit 111 and the initial value calculation unit 112 may be included in the radio control device 11, and only the change amount calculation unit 113 may be included in the terrestrial radio device 14.

[0015] <First Data Transmission Device> The first data transmission device 12 is a ground-side device that performs data transmission at a layer higher than the physical layer that controls the wireless physical connection that is the transmission medium.

[0016] <Backhaul Network> The backhaul network 13 is a relay line / network that connects terminal access lines with a central core communication network "backbone line." In this embodiment, the backhaul network 13 connects the radio control device 11, the first data transmission device 12, and the terrestrial radio device 14.

[0017] <Terrestrial Radio Device> The terrestrial radio device 14 is a radio station for radio communication that is fixed on the ground of the radio communication system 100. The terrestrial radio device 14 mainly includes a transmitter, a receiver, or a combination of a transmitter and a receiver, and communicates wirelessly with the mobile radio device 15. In the radio communication system 100, there are multiple different terrestrial radio devices 14, each connected to a mobile radio device 15. Each mobile radio device 15 connects to one terrestrial radio device 14, but each terrestrial radio device 14 can connect to multiple mobile radio devices 15.

[0018] The terrestrial radio device 14 is interconnected with the radio control device 11 and the first data transmission device 12 via a backhaul network 13. The terrestrial radio device 14 communicates wirelessly with the mobile radio device 15, and transmits and receives upper layer data between these two devices using the wireless communication between the terrestrial radio device 14 and the mobile radio device 15 as a bearer. The terrestrial radio device 14 holds a frequency hopping pattern, and receives the frequency hopping pattern from the radio control device 11 when the terrestrial radio device 14 is started up. The received frequency hopping pattern is held in a storage device such as a flash memory.

[0019] <Mobile Radio Device> The mobile radio device 15 is a radio station that is carried and operates while moving or while stopped at an unspecified location. The mobile radio device 15 mainly includes a transmitter, a receiver, or a combination of a transmitter and a receiver, and communicates wirelessly with the terrestrial radio device 14. The mobile radio device 15 is connected to the terrestrial radio device 14 via wireless communication. The mobile radio device 15 wirelessly connects to any terrestrial radio device 14, and sets the same frequency hopping pattern as the terrestrial radio device 14 holds for itself.

[0020] When the mobile radio device 15 connects to another terrestrial radio device 14 by handover, it sets the frequency hopping pattern to that of the newly connected terrestrial radio device 14. The frequency hopping pattern between the mobile radio device 15 and the terrestrial radio device 14 can be synchronized, for example, by transmitting the hopping pattern itself in communication between the terrestrial radio device 14 and the mobile radio device 15. The frequency hopping pattern between the mobile radio device 15 and the terrestrial radio device 14 can be synchronized, for example, by using a protocol that enables the mobile radio device 15 to autonomously generate a hopping pattern based on the identifier of the terrestrial radio device 14 to which it is newly connected.

[0021] In this embodiment, the mobile wireless device 15 functions as a part of a wireless terminal of the wireless communication system 100. For example, the mobile wireless device 15 is integrated with the second data transmission device 16 and functions as a smartphone.

[0022] <Second Data Transmission Device> The second data transmission device 16 is a device on the mobile device side that performs data transmission at a layer higher than the physical layer that controls the wireless physical connection that is the transmission medium.

[0023] Next, the relationship between the time division channel and the frequency hopping pattern sequence will be explained. Fig. 3 is a diagram showing the relationship between the time division channel and the frequency hopping pattern sequence. The upper part of Fig. 3 shows the time division channels of two terrestrial radio units 14, terrestrial radio unit 14a and terrestrial radio unit 14b. The time length of the time division channel of the terrestrial radio unit 14 is Tch seconds. In other words, the frequency of the terrestrial radio unit 14 changes every Tch seconds.

[0024] The upper part of Fig. 3 shows the time division channels 30 assigned to the terrestrial radio units 14. In this embodiment, 12 time division channels 30 are assigned to each of the terrestrial radio units 14a and 14b. Here, "X, Y" indicates the Yth time division channel assigned to the Xth terrestrial radio unit 14. For example, the time division channels 30 assigned to the terrestrial radio unit 14a are "1,1", "1,2", ... "1,12", respectively. Similarly, the time division channels 30 assigned to the terrestrial radio unit 14b are "2,1", "2,2", ... "2,12", respectively.

[0025] In this embodiment, the radio control device 11 centrally manages the allocation of time-division channels, but the allocation may be performed by other methods. For example, the terrestrial radio device 14 may allocate the channels.

[0026] The middle part of Fig. 3 shows an example of a frequency hopping pattern sequence corresponding to a time division channel. The middle part of Fig. 3 shows a case where the frequency is switched every time the time division channel changes, and one sequence is assigned to each time division channel 30 assigned to the terrestrial radio unit 14a. For example, among the time division channels 30 assigned to the terrestrial radio unit 14a, "FH X, Y" indicates the frequency number used by the Xth terrestrial radio unit 14 in the Yth time division channel or time division channel group.

[0027] The sequence length of the frequency hopping pattern is finite. For example, in the middle part of FIG. 3, the sequence length is 6. That is, the time division channels 30 assigned to the terrestrial radio units 14a and 14b repeat a hopping pattern consisting of six frequencies twice. For example, the frequency numbers "FH 1,1" ... "FH 1,6" are assigned to the time division channels 30 "1,1", "1,2", ... "1,6" assigned to the terrestrial radio unit 14a. Similarly, the frequency numbers "FH 1,1" ... "FH 1,6" are assigned to the time division channels 30 "1,7", "1,8", ... "1,12" assigned to the terrestrial radio unit 14a.

[0028] For example, frequency numbers "FH 2,1" ... "FH 2,6" are assigned to the time division channels 30 "2,1", "2,2", ... "2,6" assigned to the terrestrial radio unit 14b. Similarly, frequency numbers "FH 2,1" ... "FH 2,6" are assigned to the time division channels 30 "2,7", "2,8", ... "2,12" assigned to the terrestrial radio unit 14b.

[0029] The bottom part of Figure 3 shows an example of a frequency hopping pattern sequence corresponding to a different time division channel from that shown in the middle part of Figure 3. The bottom part of Figure 3 shows a case where a plurality of time division channels are grouped together and the frequency is switched each time a group is crossed. Here, as in the middle part of Figure 3, the sequence length of the frequency hopping pattern is finite, and in the bottom part, the sequence length is 3. In other words, in the bottom part of Figure 3, the frequency is repeatedly switched every time the time division channel changes by two.

[0030] In this embodiment, the sequence length is 6 or 3, but it may be any other length. For example, it may be any one of 1 to 9.

[0031] Next, the calculation process of the frequency hopping pattern will be described. The sequence of the frequency hopping pattern calculated by the hopping pattern calculation unit 111 is expressed by the following equation (1).

[0032] In equation (1), F(n) represents a sequence of a frequency hopping pattern. In this case, n represents an index within the sequence and is a natural number starting from 0. Here, when n=0, F(n) is a value calculated by the initial value calculation unit 112. N ｃｈ indicates the number of frequency channels in the system. mod indicates an operation to obtain the remainder of the division result. Δ(n) indicates the difference in the frequency channel number that changes between F(n-1) and F(n). For example, Δ(0) indicates the difference in the frequency channel number between F(L-1) and F(0). In this case, L is the sequence length.

[0033] That is, Δ(n) is expressed as the n-th element of the hop change amount array Δ. Here, the hop change amount array Δ is expressed as an array (including one expressed as a mathematical matrix) by the following formula (2).

[0034] Δ(n) is calculated by the change amount calculation unit 113. At this time, the elements of the array Δ calculated by the change amount calculation unit 113 do not have the same number of consecutive elements. Furthermore, if the elements of the array Δ calculated by the change amount calculation unit 113 do not have the same number of consecutive elements, the calculation may be performed using a specific recurrence formula.

[0035] For example, when explaining the frequency hopping pattern of the terrestrial radio device 14a, the hopping pattern of the terrestrial radio device 14a is expressed by equation (3).

[0036] Similarly, the hopping pattern of the ground radio unit 14b is expressed by equation (4).

[0037] When F(m-1) of the terrestrial radio unit 14a and F(o-1) of the terrestrial radio unit 14b match and Δ(m) and Δ(o) match, adding the same hop change amount sequence to the same hopping pattern will result in the frequencies matching twice in a row. This will cause mutual interference to occur continuously. Furthermore, when Δ(m+1) and Δ(o+1) also match, adding the same hop change amount sequence to the same hopping pattern and then adding the same hop change amount sequence again will cause the frequencies to match three times in a row. This will cause mutual interference to occur three times in a row.

[0038] At this time, if Δ(m+1) and Δ(o+1) do not match, interference does not occur three times in succession between the terrestrial radio devices 14a and 14b.

[0039] In other words, when a frequency assigned to a terrestrial radio device 14 matches a sequence Δ starting from a certain frequency N times in a row, N+1 consecutive interferences will occur with a frequency assigned to a different terrestrial radio device 14. By analyzing the sequence of the frequency hopping pattern in this way, the maximum number of consecutive interferences can be identified.

[0040] Next, an example of a frequency hopping pattern sequence and a hop change amount arrangement will be described. Figures 4 and 5 are diagrams showing an example of a frequency hopping pattern sequence and a hop change amount arrangement. In Figures 4 and 5, there are 16 terrestrial radio devices 14 treated as base stations, and the frequency hopping pattern sequences of each terrestrial radio device 14 are shown. The 16 terrestrial radio devices 14 are treated as base stations 1 to 16. In Figures 4 and 5, the horizontal direction indicates time division channels. The sequence length is 9, and the frequency channel is switched when the time division channel is switched.

[0041] In the frequency hopping pattern of Fig. 4, the hopping sequence length is 16, and the hop change amount array is common to all base stations and all element values ​​are standardized to 5. In the past, frequency hopping patterns often had the same hop change amount as shown in Fig. 4. In other words, the elements of the hop change amount array Δ are the same.

[0042] In FIG. 4, if the elements of the array Δ are the same for all terrestrial radio devices 14, and the timing of a specific frequency channel (e.g., CH0) is aligned between different base stations due to a timing difference in frequency hopping, subsequent hop change amount arrays Δ will also be perfectly consistent, resulting in continuous interference.

[0043] 4, for example, frequency channel 9 is used in CH1 of base station 5. Similarly, frequency channel 9 is also used in CH2 of base station 16. When base station 5 and base station 16 are synchronized, the frequency hopping timing is also the same, so when base station 5 and base station 16 use different frequency channels in CH1, no mutual interference occurs between the base stations.

[0044] However, if base station 5 and base station 16 are not synchronized, for example, if base station 5 is using CH1 while base station 16 is using CH2, then both will use frequency channel 9. Because the hop change amounts of base station 5 and base station 16 are the same, the frequency channel when base station 5 frequency hops to CH2 is frequency channel 14, which is the same as the frequency channel when base station 16 frequency hops to CH3.

[0045] That is, the frequency channel when base station 5 performs frequency hopping and the frequency channel when base station 16 performs frequency hopping continue to occur between the base stations depending on the degree of timing deviation.

[0046] As a result, the wireless communication system 100 is in a state where wireless communication interference continues to occur or does not occur at all, resulting in an unstable degree of mutual interference. In this case, there is a risk that wireless communication will become completely unusable due to mutual interference.

[0047] In order to prevent such wireless communication from becoming unusable due to mutual interference, in the wireless communication system 100 of the present disclosure, the wireless control device 11 calculates a frequency hopping pattern to prevent mutual interference even when the base stations are not synchronized.

[0048] Fig. 5 illustrates mutual interference when the hop change amount differs for each frequency hopping. Fig. 5 differs from Fig. 4 in that the elements of the hop change amount array Δ are at least consecutively different. Specifically, in the example of Fig. 5, for example, when frequency hopping from time division channel (CH) 4 to 5 of base station 5, the hop change amount is 11, but when frequency hopping from CH 5 to 6, the hop change amount is 9. In this case, frequency channel 0 is selected for CH 4 of base station 5, and frequency channel 11 is selected for CH 5. Similarly, frequency channel 0 is selected for CH 7 of base station 11, and frequency channel 11 is selected for CH 8.

[0049] At this time, mutual interference in the wireless communication system 100 when the frequency hopping timings of the base stations are synchronized and when they are not synchronized will be described.

[0050] <When the frequency hopping timing is synchronized> First, we will explain the case where the frequency hopping timing between base stations is synchronized. When the frequency hopping timing between base stations is synchronized, for example, when timing is synchronized between base station 5 and base station 11, wireless communication is generally performed on the same time division channel. In other words, when base station 5 is communicating on CH4, base station 11 is also communicating on CH4. In this case, base station 5 is communicating on frequency channel 0. Similarly, base station 11 is communicating on frequency channel 6.

[0051] The timing at which the time division channel of base station 5 switches and the timing at which the time division channel of base station 11 switches are synchronized, so they switch almost simultaneously. In other words, CH5 of base station 5 communicates on frequency channel 11, and CH5 of base station 11 starts communication on frequency channel 1. At this time, the frequency channel on which base station 5 communicates and the frequency channel on which base station 11 communicates are different, so no mutual interference occurs.

[0052] Similarly, even when switched to time division channel 6, the frequency channel used by base station 5 to communicate and the frequency channel used by base station 11 to communicate are different, so mutual interference will not occur.

[0053] <When the Timing of Frequency Hopping is Not Synchronized> Next, a case where the frequency hopping between base stations is not synchronized will be described. When the timing of frequency hopping between base stations is not synchronized, for example, when timing synchronization is not established between base station 5 and base station 14, there is a risk that wireless communication will be performed using different time division channels. For example, when base station 5 is communicating using time division channel 4, base station 14 may be communicating using time division channel 7. In other words, the switching of the time division channels of the base stations is independent for each base station, and the switching of the time division channel of base station 11 may be faster than the switching of the time division channel of base station 5.

[0054] At this time, base station 5 is communicating on frequency channel 0, and at the same time, base station 14 is communicating on frequency channel 0. Next, when base station 5 switches to time division channel 5, it communicates on frequency channel 11. At this time, when base station 14 switches to time division channel 8, it communicates on frequency channel 11.

[0055] That is, if frequency channel 0 is selected at the same time in base station 5 and base station 14, communication interference will occur continuously in frequency channel 11 in the next time division channel.

[0056] 5, when the terrestrial radio device 14a is the base station 5 and the terrestrial radio device 14b is the base station 14, the sequence of the base station 5 is expressed by equation (3). Similarly, the sequence of the base station 14 is expressed by equation (4).

[0057] For example, when base station 5 communicates on time division channel 4, n = 4 in equation (3), F(m) = 0, and F(m+1) = 11. For example, when base station 14 communicates on time division channel 7, m = 7 in equation (4), F(o) = 0, and F(o+1) = 11.

[0058] That is, there is a case where base station 5 communicates on time division channel 4 and base station 14 communicates on time division channel 7. In this case, F(m) = 0, and similarly, F(o) = 0. In other words, frequency channel 0 used when base station 5 communicates on time division channel 4 is the same frequency as frequency channel 0 used when base station 14 communicates on time division channel 7, and mutual interference occurs.

[0059] When base station 5 performs frequency hopping, it communicates using frequency channel 11, which it uses for time division channel 5. At this time, when base station 14 similarly performs frequency hopping, it communicates using frequency channel 11, which it uses for time division channel 8. In other words, frequency channel 11, which base station 5 uses when communicating on time division channel 5, is the same frequency as frequency channel 11, which base station 14 uses when communicating on time division channel 8.

[0060] As a result, when base station 5 and base station 14 perform frequency hopping, there is a risk of mutual interference occurring continuously.

[0061] In this way, if the switching timing of the time division channels is not synchronized between base stations, there is a risk that a plurality of base stations will use the same frequency channel consecutively at a specific timing.

[0062] The radio control device 11 can suppress the occurrence of continuous interference by paying attention to the design of the array Δ. For example, when designing a hopping pattern such as that shown in Figure 5, the following points should be taken into consideration: (1) The same array Δ should be applied to all base stations. (2) F(n-1) immediately preceding Δ(n) should have a different value between base stations. (3) The sum of the array Δ should be an integer multiple of the number of frequency channels (for example, an integer multiple of 16 in the case of Figure 5). (4) There should be no identical values ​​within the array Δ.

[0063] If these conditions are satisfied, for example, if the allocation of time division channel 0 is the same as in Figure 5, the conditions can be satisfied by applying the arrangement Δ to all base stations as follows: 1, 7, 11, 2, 12, 5, 9, 13, 4. This makes it possible to design a hopping pattern that avoids two consecutive interferences.

[0064] In the present invention, it is assumed that the number of base stations is less than the number of frequency channels, which makes it possible to avoid continuous interference between neighboring base stations.

[0065] Furthermore, if there are more base stations, i.e., terrestrial radio devices 14, than there are frequency channels, the hopping patterns are reused after ensuring sufficient distance between each base station and reducing mutual interference to a negligible level.

[0066] As described above, according to this embodiment, it is possible to prevent mutual interference caused by frequency hopping deviations from occurring continuously among multiple terrestrial radio devices 14 that use different frequency hopping pattern sequences. In other words, even if the frequency hopping of multiple terrestrial radio devices 14 is not synchronized, it is possible to set the different terrestrial radio devices 14 to avoid using the same frequency channel continuously as much as possible. This makes it possible to avoid an extreme decrease in the reliability of data communication due to mutual interference between the terrestrial radio devices 14 and the mobile radio devices 15.

[0067] [Modification] Next, a modification of the wireless communication system 100 of the first embodiment will be described. The wireless communication system 200 of the modification differs from the first embodiment in that, in order to increase the reliability of communication between the terrestrial wireless device 14 and the mobile wireless device 15, the same data is transmitted multiple times in succession, and the transmission is successful at least once. In the following description, components that are the same as or equivalent to those of the first embodiment and the like will be assigned the same reference numerals, and their description will be simplified or omitted.

[0068] As shown in Fig. 5, the wireless communication system 100 can estimate the maximum number of consecutive times that mutual interference can occur based on the frequency hopping pattern sequence and the hop change amount arrangement. For example, based on Fig. 5, the wireless communication system 100 may experience a maximum of two consecutive times of interference.

[0069] The wireless communication system 200 transmits using a frequency hopping pattern that prevents three or more consecutive interferences. For example, if the sequence length of the frequency hopping pattern of the wireless communication system 200 is nine, as in Fig. 3, the wireless communication system 200 transmits by dividing the signal into three time-division channels in the first half, three time-division channels in the middle, and three time-division channels in the last half. In other words, a time-division channel with a sequence length of three is transmitted three times in succession.

[0070] In this modification, the wireless communication system 200 divides the time division channel into channels with a sequence length of 3 for transmission, but may divide the time division channel into other sequence lengths as long as mutual interference does not occur. For example, in the frequency hopping pattern of Fig. 3, the sequence length of the time division channel is divided into 3 because mutual interference does not occur more than twice in a row, but if the frequency hopping pattern does not cause mutual interference to occur more than three times in a row, the sequence length of the time division channel may be divided into 4.

[0071] As described above, according to this modification, the wireless communication system 200 transmits data continuously more times than the upper limit number of times that mutual interference occurs consecutively. In other words, the wireless communication system 200 can avoid mutual interference at least once. As a result, even if the frequency hopping of the multiple terrestrial wireless devices 14 is not synchronized, it is possible to create a state in which mutual interference does not occur between the base stations at least once, thereby improving the reliability of data communication.

[0072] The present invention can also take the following aspects. (Aspect 1) A radio device comprising: a change amount calculation unit that calculates a change amount of a frequency channel in a frequency hopping pattern of frequency hopping repeatedly performed by a plurality of radio devices; and a hopping pattern calculation unit that calculates the frequency hopping pattern based on the change amount of the frequency channel, wherein the hopping pattern calculation unit calculates the frequency hopping pattern such that different radio devices do not consecutively use the same frequency channel even if the change amount is the same. (Aspect 2) The radio device according to Aspect 1, wherein the hopping pattern calculation unit calculates the frequency hopping pattern based on the following equation (1): (Aspect 3) The wireless device according to aspect 1 or 2, wherein the change amount calculation unit represents the change amount as a change amount array expressed based on the following equation (2), and the change amount array does not include consecutive identical elements. (Aspect 4) The wireless device according to Aspect 3, wherein the elements included in the change amount array are not the same three times in a row. (Aspect 5) The wireless device according to any one of Aspects 1 to 4, further comprising: an initial value calculation unit that calculates an initial value of the frequency hopping pattern, wherein the hopping pattern calculation unit calculates the frequency hopping pattern based on the initial value and the change amount. (Aspect 6) A frequency hopping pattern generation method that calculates a change amount of a frequency channel of a frequency hopping pattern of frequency hopping repeatedly performed by a plurality of wireless devices, and calculates the frequency hopping pattern based on the change amount of the frequency channel. (Aspect 7) A program that causes a computer to execute: a change amount calculation step that calculates a change amount of a frequency channel of a frequency hopping pattern of frequency hopping repeatedly performed by a plurality of wireless devices; and a hopping pattern calculation step that calculates the frequency hopping pattern based on the change amount of the frequency channel. (Aspect 8) A wireless communication system comprising: a wireless control device that calculates a frequency hopping pattern for frequency hopping repeatedly performed by a plurality of terrestrial wireless devices and controls wireless communication; terrestrial wireless devices that are transmitters or receivers or a combination of a transmitter and a receiver fixed on the ground; and mobile wireless devices that are transmitters or receivers or a combination of a transmitter and a receiver that are carried and operated while moving or stopped at an unspecified location, wherein the wireless control device calculates the frequency hopping pattern so that the same frequency channel is not used consecutively between different terrestrial wireless devices, and the terrestrial wireless devices and the mobile wireless devices perform frequency hopping based on the frequency hopping pattern calculated by the wireless control device.

[0073] REFERENCE SIGNS LIST 11 Radio control device 12 First data transmission device 13 Backhaul network 14 Terrestrial radio device 15 Mobile radio device 16 Second data transmission device 30 Time division channel

Claims

1. a variation calculation unit that calculates a variation of a frequency channel in a frequency hopping pattern of frequency hopping repeatedly performed by a plurality of wireless devices; a hopping pattern calculation unit that calculates the frequency hopping pattern based on the amount of change in the frequency channel, the hopping pattern calculation unit calculates the frequency hopping pattern such that different wireless devices do not consecutively use the same frequency channel even if the change amount is the same; The change amount calculation unit represents the change amount as a change amount array expressed based on the following formula (2): The variation array does not include consecutive identical elements. Radio equipment. [Equation 1]

2. 2. The wireless device according to claim 1, The hopping pattern calculation unit calculates the frequency hopping pattern based on the following equation (1): Radio equipment. [Equation 2]

3. 2. The wireless device according to claim 1, The element included in the variation array is not the same three times in a row. Radio equipment.

4. 2. The wireless device according to claim 1, an initial value calculation unit that calculates an initial value of the frequency hopping pattern, The hopping pattern calculation unit calculates the frequency hopping pattern based on the initial value and the amount of change. Radio equipment.

5. Calculating a change amount of a frequency channel in a frequency hopping pattern of frequency hopping repeatedly performed by a plurality of wireless devices; A frequency hopping pattern generation method for calculating the frequency hopping pattern based on the amount of change in the frequency channel, comprising: The change amount is expressed by a change amount array expressed based on the following formula (2), The variation array does not include consecutive identical elements. A method for generating frequency hopping patterns. [Equation 3]

6. a change amount calculation step of calculating a change amount of a frequency channel of a frequency hopping pattern of frequency hopping repeatedly executed by a plurality of wireless devices; a hopping pattern calculation step of calculating the frequency hopping pattern based on the amount of change in the frequency channel, The change amount is expressed by a change amount array expressed based on the following formula (2), The program, wherein the variation array does not include consecutive identical elements. [Equation 4]

7. a radio control device that calculates a change amount of a frequency channel in a frequency hopping pattern of frequency hopping repeatedly performed by a plurality of terrestrial radio devices and controls radio communication; a ground radio device which is a transmitter or receiver or a combination of a transmitter and a receiver fixed on the ground; A mobile radio device is provided, which is a transmitter or a receiver or a combination of a transmitter and a receiver, and which is carried and operated while moving or stopped at an unspecified location, The wireless control device The change amount is expressed by a change amount array expressed based on the following formula (2), [Equation 5] the variation array does not include consecutive identical elements; The terrestrial radio equipment and the mobile radio equipment perform frequency hopping based on the frequency hopping pattern calculated by the radio control device. Wireless communication system.

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