Delay-guaranteed wireless communication terminal and delay-guaranteed wireless communication method

Abstract

To provide a delay time guaranteed wireless communication terminal that guarantees a delay time in a wireless communication system.SOLUTION: A delay time guaranteed wireless communication terminal includes a synchronization information transmitting / receiving unit that wirelessly transmits / receives synchronization information which is information for synchronizing a parent terminal and other child terminals which is one of a plurality of child terminals that wirelessly communicate with a parent terminal in a wireless communication system in a first communication band, a synchronization processing unit that synchronizes with each of the other child terminals after a first predetermined time interval, and controls the timing of transmitting general information which is general information other than the synchronization information by an arbitration point provided at every second predetermined time, and a general information transmission / reception unit that senses that there is no transmission of general information by the other child terminals and transmits the general information wirelessly via a second communication band, and the synchronization processing unit determines whether to transmit the general information by referring to the result of sensing of the general information by the other child terminals by the general information transmission / reception unit, and the general information transmission / reception unit obeys an instruction from the synchronization processing unit.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a delay-guaranteed wireless communication terminal and a delay-guaranteed wireless communication method. [Background technology]

[0002] For example, Non-Patent Document 1 discloses a system that guarantees delay times by performing time synchronization in communications via a wired optical communications network. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] Yunzhuo Wang, Fumihiko Nakamura, Nobuyasu Shiga, Satoshi Yasuda, Nicolas Chauvet, Makoto Naruse; Single-word arbitration optical network using time synchronization; Abstracts of the 80th Autumn Meeting of the Japan Society of Applied Physics, 2019. Summary of the Invention [Problem to be solved by the invention]

[0004] However, the conventional method described in Non-Patent Document 1 is a method for guaranteeing delay times for wired communications, and does not take into consideration application to wireless communications.

[0005] An object of one aspect of an embodiment of the present invention is to provide a delay-guaranteed wireless communication terminal that guarantees a delay time in a wireless communication system. [Means for solving the problem]

[0006] A synchronization information transmitting / receiving unit is one of a plurality of child terminals that wirelessly communicate with a parent terminal in a wireless communication system, and transmits and receives synchronization information, which is information for synchronizing with the parent terminal and the other child terminals, wirelessly via a first communication band, and synchronizes with each of the other child terminals at a first predetermined time interval, and determines a timing for transmitting general information, which is general information other than the synchronization information,A time longer than a time obtained by multiplying the first predetermined time by the number of child terminals, which is the number of the child terminals. Control is performed by arbitration points provided at second predetermined times. By this, the delay time from when the child terminal receives a transmission request from the parent terminal to when the child terminal transmits the general information is controlled. a general information transmitting / receiving unit that detects that no general information is being transmitted by other child terminals and wirelessly transmits the general information via a second communication band, and the general information transmitting / receiving unit transmits the general information to other child terminals via the second communication band. but General information Whether or not you have sent Refer to the results of the sensing For other child terminals Decide whether or not to send general information, If the determination is positive, instruct the general information transmitting / receiving unit to transmit the general information; The general information transmitting and receiving unit includes the synchronization processing unit Transmission of said general information by Follow the instructions and transmits the general information to the other child terminals. A delay-guaranteed wireless communication terminal is provided.

[0007] A delay-guaranteed wireless communication method for one of a plurality of child terminals that wirelessly communicate with a parent terminal in a wireless communication system, comprising: a first step of wirelessly transmitting and receiving synchronization information, which is information for synchronizing with the parent terminal and the other child terminals, via a first communication band; 1. Synchronize at a specified time interval, A second predetermined time longer than a time obtained by multiplying the first predetermined time by the number of child terminals, which is the number of the child terminals. General information, which is general information other than synchronization information, is arbitrated at an arbitration point set at a predetermined time. of send Timing Control By this, the delay time from when the child terminal receives a transmission request from the parent terminal to when the child terminal transmits the general information is controlled. Second step and other child devices but General Information of send Whether or not Refer to the results of the sensing For the other child terminals Whether to instruct the sending of general information That Judgment If the result of the judgment is positive, the transmission of the general information is instructed. and the third step, According to the instruction to transmit the general information, to other child terminals and a fourth step of wirelessly transmitting the general information via the second communication band. Effect of the Invention

[0008] According to the present invention, it is possible to realize a delay-guaranteed wireless communication terminal that guarantees delay time in a wireless communication system. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a block diagram showing a configuration of a wireless communication system including a delay-guaranteed wireless communication terminal according to a first embodiment. [Diagram 2] FIG. 2 is a sequence diagram illustrating functions provided in the wireless communication system according to the first embodiment. [Diagram 3] FIG. 3 is a timing chart for explaining the delay-guaranteed wireless communication function according to the first embodiment. [Figure 4] FIG. 4 is a flowchart showing a processing procedure of delay-guaranteed wireless communication processing according to the first embodiment. [Diagram 5] FIG. 5 is a diagram for explaining the effects of the first embodiment. [Figure 6] FIG. 6 is a conceptual diagram showing a configuration of a wireless communication system including a delay-guaranteed wireless communication terminal according to the second embodiment. [Figure 7] FIG. 7 is a diagram for explaining the effects of the second embodiment. [Figure 8] FIG. 8 is a diagram for explaining the effects of the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] An embodiment of the present invention will be described in detail below with reference to the drawings.

[0011] (First embodiment) Fig. 1 is a block diagram showing a configuration of a wireless communication system including a delay-guaranteed wireless communication terminal (hereinafter, this may be called a child terminal) 2A according to the present embodiment. As shown in Fig. 1, in the wireless communication system according to the present embodiment, for example, a parent terminal 1 and a plurality of delay-guaranteed wireless communication terminals 2 (2A to 2C) communicate with each other wirelessly.

[0012] The parent terminal 1 is, for example, an access point, and includes a parent terminal synchronization information transmitting / receiving unit 5 and a parent terminal general information transmitting / receiving unit 6. The parent terminal synchronization information transmitting / receiving unit 5 and the parent terminal general information transmitting / receiving unit 6 are, for example, programs recorded in a RAM (Random Access Memory) that are called by a CPU (Central Processing Unit).

[0013] The parent terminal synchronization information transmitting / receiving unit 5 transmits and receives synchronization information, which is information for synchronizing with the child terminal 2, wirelessly to and from the child terminal 2 via the first communication band 3. Specifically, the parent terminal 1 transmits and receives synchronization information to and from, for example, the child terminal 2A, as described later.

[0014] Wireless communication via the first communication band 3 is realized by a wireless direction time comparison technique such as Wi-Wi (Wireless two-way interferometry) in the band of, for example, 920 MHz.

[0015] The parent terminal general information transmitting / receiving unit 6 transmits, via the second communication band 4 to the child terminals 2A to 2C, a general information transmission start notification, which is a notification for starting general information, which is general information other than synchronization information.

[0016] The wireless communication via the second communication band 4 is realized by wireless communication using a general wireless LAN, for example, in the 2.4 GHz band. When the child terminals 2A to 2C receive the general information transmission start notification, they start transmitting general information. In the second communication band 4, for example, the transmission speed of the radio wave is the speed of light c, the radius of the radio wave sensitivity limit is the limit radius SR, and the range up to the radio wave sensitivity limit is the radio wave range 10.

[0017] Since the synchronization information handled in the first communication band 3 has a smaller amount of information than the general information handled in the second communication band 4, the first communication band 3 can have a lower frequency band than the second communication band 4.

[0018] Each of the child terminals 2A to 2C is, for example, a smartphone, and includes a synchronization information transmitting / receiving unit 7, a synchronization processing unit 8, and a general information transmitting / receiving unit 9. The synchronization information transmitting / receiving unit 7, the synchronization processing unit 8, and the general information transmitting / receiving unit 9 are, for example, programs recorded in a RAM (Random Access Memory) that are called by a CPU (Central Processing Unit).

[0019] Here, the child terminal 2A will be described. The synchronization information transmitting / receiving unit 7 wirelessly transmits and receives, via the first communication band 3, synchronization information for synchronizing with the parent terminal 1 and the other child terminals 2B and 2C.

[0020] The synchronization processing unit 8 of the child terminal 2A synchronizes with each of the other child terminals 2B and 2C at a first predetermined time T i,j and synchronizes at a second predetermined time T ap The timing of transmitting general information is controlled by arbitration points provided for each device.

[0021] The general information transmitting / receiving unit 9 wirelessly transmits the general information via the second communication band 4. In addition, the general information transmitting / receiving unit 9 senses whether or not there is a radio wave for transmitting the general information in the vicinity of the child terminal 2A, for example.

[0022] In addition, the synchronization processing unit 8 of terminal 2A determines whether or not other child terminals 2B, 2C are transmitting general information by, for example, referring to the results detected by the general information transmitting / receiving unit 9 as to whether or not there are radio waves transmitting general information in the vicinity of child terminal 2A, and decides whether or not to give an instruction to transmit general information.

[0023] Therefore, while the child terminals 2A to 2C are transmitting information, the child terminals 2A to 2C do not transmit information even if a transmission request is made. delay This refers to the maximum time from when child terminal 2A receives a transmission request from parent terminal 1 until when it transmits general information.

[0024] Next, a description will be given with reference to Fig. 2. Fig. 2 is a sequence diagram for explaining functions of the wireless communication system according to this embodiment. In the wireless communication system according to this embodiment, a synchronization process S1 for realizing the function, a general information transmission start process S2 for realizing the general information transmission start function, and general information transmission processes S3 to S5 for realizing the general information transmission function are performed.

[0025] The parent terminal synchronization information transmitting / receiving unit 5 of the parent terminal 1 and the synchronization information transmitting / receiving units 7 of the child terminals 2A to 2C each communicate wirelessly via a first communication band 3. The parent terminal general information transmitting / receiving unit 6 of the parent terminal 1 and the general information transmitting / receiving units 9 of the child terminals 2A to 2C each communicate wirelessly via a second communication band 4. The synchronization information is wirelessly communicated via the first communication band 3, and the general information is wirelessly communicated via the second communication band 4.

[0026] Furthermore, the parent terminal synchronization information transmitting / receiving unit 5 and the parent terminal general information transmitting / receiving unit 6 of the parent terminal 1 exchange information, for example, via a data transmission path, inside the parent terminal 1. The synchronization information transmitting / receiving unit 7 of each of the child terminals 2A to 2C, the synchronization processing unit 8 of each of the child terminals 2A to 2C, and the general information transmitting / receiving unit 9 of each of the child terminals 2A to 2C exchange information, for example, via a data transmission path, inside each of the child terminals 2A to 2C.

[0027] The synchronization process S1 is a process such as P2P (Peer to Peer) in which synchronization is performed between each of the parent terminal 6 and two of the child terminals 2A to 2C, and the parent terminal 6 and the child terminals 2A to 2C are synchronized as a result.

[0028] Specifically, the parent terminal synchronization information transmitting / receiving unit 5 of the parent terminal 1 transmits synchronization information to the synchronization information transmitting / receiving unit 7 of the child terminal 2A (S1A). Next, the synchronization information transmitting / receiving unit 7 of the child terminal 2A transmits synchronization information to the parent terminal synchronization information transmitting / receiving unit 5 of the parent terminal 1 (S1B).

[0029] Here, for example, the synchronization information transmitted by the parent terminal synchronization information transmitting / receiving unit 5 of the parent terminal 1 is the time information of the parent terminal 1, and the synchronization information transmitted by the synchronization information transmitting / receiving unit 7 of the child terminal 2A is the time information with the child terminal 2A. The same applies to the synchronization information transmitted below. The parent terminal 1 and the child terminal 2A synchronize using the time information of the parent terminal 1 and the time information of the child terminal 2A.

[0030] Next, the synchronization information transmitting / receiving unit 7 of the child terminal 2A transmits synchronization information to the synchronization information transmitting / receiving unit 7 of the child terminal 2B (S1C). Next, the synchronization information transmitting / receiving unit 7 of the child terminal 2B transmits synchronization information to the synchronization information transmitting / receiving unit 7 of the child terminal 2A (S1D). The child terminals 2A and 2B perform synchronization using the time information of the child terminal 2A and the time information of the child terminal 2B.

[0031] Next, the synchronization information transmitting / receiving unit 7 of child terminal 2B transmits synchronization information to the synchronization information transmitting / receiving unit 7 of child terminal 2C (S1E). Next, the synchronization information transmitting / receiving unit 7 of child terminal 2C transmits synchronization information to the synchronization information transmitting / receiving unit 7 of child terminal 2B (S1F). Child terminals 2B and 2C perform synchronization using the time information of child terminal 1A and the time information of child terminal 2B.

[0032] After the synchronization process S1 is completed or in parallel with the synchronization process S1, the parent terminal general information transmitting / receiving unit 6 of the parent terminal 1 starts a general information transmission start process S2. Specifically, the parent terminal general information transmitting / receiving unit 6 of the parent terminal 1 transmits a general information transmission start notification to the general information transmitting / receiving unit 9 of each of the child terminals 2A to 2C (S2A to S2C). Note that, for example, after transmitting the general information transmission start notification, the parent terminal general information transmitting / receiving unit 6 of the parent terminal 1 transmits a transmission request to the general information transmitting / receiving unit 9 of each of the child terminals 2A to 2C.

[0033] Upon receiving the general information transmission start notification and transmission request from the parent terminal 1, the general information transmitting / receiving units 9 of the child terminals 2A to 2C start general information transmission processing S3 to S5. In the general information transmission processing S3 to S5, each of the child terminals 2A to 2C transmits general information to each of the other child terminals 2A to 2C.

[0034] As a general information transmission process S3 performed by child terminal 2A, the general information transmitting / receiving unit 9 of child terminal 2A transmits general information to the general information transmitting / receiving units 9 of child terminals 2B and 2C (S3A, S3B). As a general information transmission process S4 performed by child terminal 2B, the general information transmitting / receiving unit 9 of child terminal 2B transmits general information to the general information transmitting / receiving units 9 of child terminals 2A and 2C (S4A, S4B). As a general information transmission process S5 performed by child terminal 2C, the general information transmitting / receiving unit 9 of child terminal 2C transmits general information to the general information transmitting / receiving units 9 of child terminals 2B and 2A (S5A, S5B).

[0035] Next, a description will be given with reference to Fig. 3. Fig. 3 is a timing chart for explaining the delay-guaranteed wireless communication function according to this embodiment. Each of the child terminals 2A to 2C performs delay-guaranteed wireless communication processing based on the delay-guaranteed wireless communication function when transmitting general information to each of the other child terminals 2A to 2C.

[0036] As shown in FIG. 3, when the general information transmission / reception unit 9 of the terminal 2A receives the general information transmission start notification, the synchronization processing unit 8 of the terminal 2A synchronizes with each of the other child terminals 2B and 2C for the first predetermined time T i,j (T 1,2 ,T 2,3 ,T 3,1 ) and synchronize at a second predetermined time T ap The transmission of general information is controlled by arbitration points provided for each device.

[0037] As described above, the general information transmitting / receiving unit 9 of the terminal 2A wirelessly transmits the general information via the second communication band 4. When synchronization is performed based on time information as in this embodiment, for example, at a first predetermined time T i,j By setting the following equation (1), equal communication opportunities are guaranteed among the child terminals 2A to 2C.

[0038] i and j are indexes indicating child terminals 2A to 2C, for example child terminal 2A is 1, child terminal 2B is 2, and child terminal 2C is 3. For child terminals 2A to 2C, there are three combinations of i and j: 1,2, 2,3, and 3,1. In this embodiment, the arbitration point is visited in the order of the indexes of child terminals 2, such as child terminals 2A, 2B, and 2C.

number

[0039] Since the synchronization information includes time information, the first predetermined time T i,j The first predetermined time T i,j As shown in equation (1), is the value obtained by dividing the diameter 2SR of the sensitivity limit for the second communication band 4, centered on the parent terminal 1, by the speed of light c, which is the speed of the medium that propagates through the second communication band.

[0040] In this embodiment, the general information transmission time T packet is a second predetermined time T ap If the guaranteed delay time T delay can be expressed as the following formula (2): Here, the number of child terminals N indicates the number of child terminals 2A to 2C.

number

[0041] The first and second predetermined times T ap The relationship between these is expressed by the following equation (3).

number

[0042] The child terminals 2A to 2C are i,j and there is a second predetermined time T between each arbitration point. ap In addition, while the other child terminals 2A to 2C are transmitting general information, the child terminals 2A to 2C do not transmit general information even if a transmission request is made.

[0043] In this embodiment, the general information transmission time T packet is a second predetermined time T ap Since these values ​​are the same, if child terminals 2A to 2C have transmitted information at the previous arbitration point, they are still transmitting information at the next arbitration point.

[0044] For this reason, the child terminals 2A to 2C cannot transmit information continuously. delay If you wait a few minutes, you'll definitely be able to send general information at some arbitration point.

[0045] Next, a description will be given with reference to Fig. 4. Fig. 4 is a flowchart showing the procedure of delay-guaranteed wireless communication processing according to this embodiment. The description will be given with a focus on the child terminal 2A. First, the synchronization processing unit 8 judges whether or not the general information transmitting / receiving unit 9 has received a transmission request (S11).

[0046] If the general information transmitting / receiving unit 9 does not receive a transmission request and step S11 returns a negative result (S11: NO), the synchronization processing unit 8 waits until a transmission request is received by performing step S11 again.

[0047] When the general information transmitting / receiving unit 9 receives a transmission request and step S11 returns a positive result (S11: YES), the synchronization processing unit 8 determines whether the current point in time is an arbitration point (S12).

[0048] If the current point is not the arbitration point and step S12 returns a negative result (S12: NO), the synchronization processing unit 8 performs step S12 again to wait until the arbitration point is reached.

[0049] If the current point in time is the arbitration point and step S12 returns a positive result (S12: YES), the synchronization processing unit 8 determines whether or not the other child terminals 2B, 2C are transmitting general information by, for example, referring to the result sensed by the general information transmitting / receiving unit 9 as to whether or not there are radio waves transmitting general information in the vicinity of the child terminal 2A (S13).

[0050] If the other child terminals 2B, 2C are transmitting general information and step S13 returns a negative result (S13: NO), the synchronization processing unit 8 waits until an arbitration point is reached by performing step S12 again.

[0051] If the other child terminals 2B, 2C have not transmitted general information and step S13 results in a positive result (S13: YES), the synchronization processing unit 8 instructs the general information transmitting / receiving unit 9 to transmit general information (S13) and terminates the delay-time-guaranteed wireless communication processing.

[0052] Next, an explanation will be given with reference to Fig. 5. Fig. 5 is a diagram for explaining the effect of this embodiment. In Fig. 5, the number of child terminals is, for example, 10. In Fig. 5, the horizontal axis indicates the bandwidth usage rate, and the vertical axis indicates the time from when a packet arrives at the head of the buffer of child terminal 2 until transmission of the packet is completed (hereinafter, this may be referred to as the delay time). In Fig. 5, the guaranteed delay time is 2500 μs.

[0053] Graph 11 shows the simulation results of a conventional wireless communication system such as CSMA / CA (Carrier Sense Multiple Access / Collision Avoidance) when excluding the bottom 10% with the longest delay times, and shows the average value after performing the simulation multiple times.

[0054] Graph 12 shows the results of a simulation of the wireless communication system according to this embodiment when the bottom 10% of delay times are excluded, and shows the average value after performing the simulation multiple times, for example.

[0055] Graph 13 shows the simulation results of the wireless communication system according to this embodiment, including the bottom 10% of systems with the longest delay times, and shows the average value obtained by carrying out the simulation multiple times, for example.

[0056] 5, in a conventional wireless communication system, the delay time diverges beyond the guaranteed delay time when the bandwidth utilization rate is near 0.5, as can be seen from graph 11. In contrast, in the wireless communication system of this embodiment, the delay time does not exceed the guaranteed delay time even when the bandwidth utilization rate is 1, as can be seen from graph 12.

[0057] Furthermore, as can be seen from graph 13, in the wireless communication system of this embodiment, when the bandwidth utilization rate exceeds 0.4, the guaranteed delay time is reached, and even when the bandwidth utilization rate is 0.4 or more, the guaranteed time is reached, so it can be said that delay can be strictly guaranteed.

[0058] As described above, the delay-guaranteed wireless communication terminal 2 according to the present embodiment is capable of guaranteeing the maximum delay time, whereas the conventional method is not capable of guaranteeing the maximum delay time, for example, delay It is possible to guarantee a delay time such as

[0059] For example, two delay-time-guaranteed wireless communication terminals 2 according to this embodiment can be used, one as an operating terminal and the other as an operated terminal, in a surgical system in which the operating terminal and the operated terminal are separated by a wall or the like within the same space.

[0060] (Second embodiment) The explanation will be given with reference to Fig. 6. Fig. 6 is a conceptual diagram showing the configuration of a wireless communication system including a delay-guaranteed wireless communication terminal 2A according to this embodiment. In this embodiment, the synchronization information includes location information in addition to time information, and the first predetermined time T i,j is expressed by the following formula (4): i,j As shown by:

number

[0061] Since the synchronization information includes time information, the first predetermined time T i,j The first predetermined time T i,j is a first predetermined time T i,j varies depending on the distance between the child terminals 2A to 2C and the other child terminals 2A to 2C adjacent to the child terminals 2A to 2C, and the distance d i,j is divided by the speed of light c, which is the speed of the medium through which the second communication band 4 propagates.

[0062] In this embodiment, the first predetermined time T i,j and a second predetermined time T ap The relationship is a first predetermined time T i,j T 1,2 ,…,T i,i+1 ,…,T N-1,N ,T 1,N Considering that it can be expressed as follows:

number

[0063] Next, a description will be given with reference to FIG. 7. FIG. 7 is a diagram for explaining the effect of this embodiment. In FIG. 7, the horizontal axis indicates the number of child terminals, which is the number of child terminals 2. In FIG. 7, the vertical axis indicates the second predetermined time T ap In this embodiment, the second predetermined time Tap is the general information transmission time T packet In FIG. 7, 224 μs is the general information transmission time T packet Let us assume that.

[0064] Graph 14 shows the simulation results of the wireless communication system in the first embodiment. Graph 15 shows the simulation results of the wireless communication system in the present embodiment.

[0065] As shown in graph 14 of FIG. 7, in the wireless communication system of the first embodiment, the second predetermined time T ap is the general information transmission time T packet If the number of entries exceeds this limit, the process will no longer be possible.

[0066] In contrast, as shown in graph 15 of FIG. 7, in the wireless communication system of the present invention, even when the number of child terminals is about 500, the second predetermined time T ap It is possible to suppress the delay to about 10 μs.

[0067] Next, an explanation will be given with reference to Fig. 8. Fig. 8 is a diagram for explaining the effect of this embodiment. Fig. 8 shows a case where the number of child terminals is 500. In Fig. 8, the horizontal axis indicates the bandwidth usage rate, and the vertical axis indicates the delay time of child terminal 2. In Fig. 8, 115000 μs is set as the guaranteed delay time.

[0068] Graph 16 shows the simulation results of the wireless communication system according to the present embodiment when the bottom 10% of delay times are excluded. Graph 17 shows the simulation results of the wireless communication system according to the present embodiment when the bottom 10% of delay times are included.

[0069] As shown in graph 16 of FIG. 8, in the wireless communication system of this embodiment, when the number of child terminals is 500, the delay time is generally about half the guaranteed delay time, excluding the bottom 10% with the longest delay times.

[0070] Furthermore, as shown in graph 17 of FIG. 8, in the wireless communication system of this embodiment, when the number of child terminals is 500, the guaranteed delay time is reached when the bandwidth utilization rate exceeds 0.2, and the guaranteed time is reached even when the bandwidth utilization rate is 0.2 or more, so it can be said that delay can be guaranteed strictly.

[0071] As described above, according to the delay-guaranteed wireless communication terminal 2 of this embodiment, hundreds or thousands of child terminals 2 in a wireless communication system can communicate with each other with the delay time guaranteed.

[0072] In the above embodiment, the parent terminal synchronization information transmitting / receiving unit 5, the parent terminal general information transmitting / receiving unit 6, the synchronization information transmitting / receiving unit 7, the synchronization processing unit 8, and the general information transmitting / receiving unit 9 are described as programs, but the present embodiment is not limited to this. For example, the parent terminal synchronization information transmitting / receiving unit 5, the parent terminal general information transmitting / receiving unit 6, the synchronization information transmitting / receiving unit 7, the synchronization processing unit 8, and the general information transmitting / receiving unit 9 may be implemented by integrated circuits. [Explanation of symbols]

[0073] 1...parent terminal, 2, 2A, 2B, 2C...child terminal, 3...first communication band, 4...second communication band, 5...parent terminal synchronization information transmission / reception unit, 6...parent terminal general information transmission / reception unit, 7...synchronization information transmission / reception unit, 8...synchronization processing unit, 9...general information transmission / reception unit, 10...radio wave range.

Claims

1. One of a plurality of child terminals that wirelessly communicate with a parent terminal in a wireless communication system, a synchronization information transmitting / receiving unit configured to wirelessly transmit and receive synchronization information, which is information for synchronizing with the parent terminal and the other child terminals, via a first communication band; a synchronization processing unit that synchronizes with each of the other child terminals at a first predetermined time interval, and controls the timing of transmitting general information, which is general information other than the synchronization information, by arbitration points provided at second predetermined times longer than the time obtained by multiplying the first predetermined time by the number of child terminals, which is the number of the child terminals, thereby controlling a delay time from when the child terminal receives a transmission request from the parent terminal to when it transmits the general information; a general information transmitting / receiving unit that detects that the general information is not being transmitted by the other child terminals and wirelessly transmits the general information via a second communication band; Equipped with The synchronization processing unit refers to a result of sensing by the general information transmitting / receiving unit as to whether the other child terminal has not transmitted the general information, and determines whether to transmit the general information to the other child terminal. If the determination is positive, the synchronization processing unit instructs the general information transmitting / receiving unit to transmit the general information. the general information transmitting / receiving unit transmits the general information to the other child terminals in accordance with an instruction to transmit the general information by the synchronization processing unit. Latency-guaranteed wireless communication terminal.

2. The synchronization information includes time information, the first predetermined time is a value obtained by dividing a diameter of a sensitivity limit of the parent terminal for the second communication band by a speed of a medium through which the second communication band is propagated; The second predetermined time is equal to a general information transmission time, which is a transmission time per unit packet of the general information.

2. The delay-guaranteed wireless communication terminal according to claim 1.

3. The synchronization information includes time information and location information, The first predetermined time varies depending on the distance between the child terminal and another child terminal adjacent to the child terminal, and is a value obtained by dividing the distance between the other adjacent child terminal and the child terminal by the speed of a medium propagating the second communication band.

2. The delay-guaranteed wireless communication terminal according to claim 1.

4. A delay-guaranteed wireless communication method for one of a plurality of child terminals that wirelessly communicate with a parent terminal in a wireless communication system, comprising: A first step of wirelessly transmitting and receiving synchronization information, which is information for synchronizing with the parent terminal and the other child terminals, via a first communication band; a second step of synchronizing with each of the other child terminals at a first predetermined time interval, and controlling the timing of transmitting general information, which is general information other than the synchronization information, by arbitration points provided at second predetermined time intervals longer than the time obtained by multiplying the first predetermined time interval by the number of child terminals, which is the number of the child terminals, thereby controlling a delay time from when the child terminal receives a transmission request from the parent terminal to when it transmits the general information; A third step of determining whether to instruct the other child terminal to transmit the general information by referring to a result of detection of whether the other child terminal has not transmitted the general information, and instructing the other child terminal to transmit the general information if the determination is positive; a fourth step of wirelessly transmitting the general information to the other child terminal via a second communication band in accordance with the instruction to transmit the general information; Equipped with A delay-guaranteed wireless communication method.

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