Wireless communication device, wireless communication method, and wireless communication system

Abstract

The present disclosure relates to a wireless communication device, a wireless communication method, and a wireless communication system for performing communication between a plurality of wireless modules. This wireless communication device comprises a plurality of wireless modules and a control circuit. The wireless modules each have a function for performing wireless communication, a function for monitoring the total transmission time for wireless communication in each given observation period, and a function for restricting wireless communication when the total transmission time reaches a given time. The control circuit has a function for determining a start timing of the observation periods so as to be different for each wireless module.

Description

Technical Field

[0001] The present disclosure relates to a wireless communication device, a wireless communication method, and a wireless communication system, and particularly to a wireless communication device, a wireless communication method, and a wireless communication system that perform communication between a plurality of wireless modules.

Background Art

[0002] Conventionally, in the field of wireless communication, a method of expanding an area by relaying a wireless signal using a repeater or the like is known. For example, when two wireless modules prepared in a repeater communicate with terminals in different areas respectively, relaying between the two areas becomes possible by transferring a packet received inside the repeater.

[0003] Here, in order to use two wireless modules in the same housing, it is necessary to avoid wireless interference. Examples to be avoided include a reception failure caused by the other party transmitting a signal while one party is receiving a signal, a collision of received signals caused by both wireless areas becoming hidden terminals, or a transmission failure caused by both parties transmitting signals simultaneously.

[0004] As avoidance means, frequency or time division is known. As frequency division, for example, a method of completely avoiding the above-described collision of wireless signals by each wireless module using sufficiently separated frequency channels is known. As time division, an avoidance method by limiting the total transmission time called duty limit is known.

Prior Art Documents

Non-Patent Documents

[0005]

Non-Patent Document 1

[0006] However, with conventional frequency-based segregation, if the number of available frequency channels is limited, it is not possible to provide multiple channels that are sufficiently far apart. In this case, overlapping or adjacent channels are used, but since each module performs carrier sensing only on the channel used by its own terminal, it cannot detect communication using adjacent channels that are outside its range. As a result, communication proceeds as configured, leading to the problem of collisions between power leaked from adjacent channels and the transmitted wireless signal.

[0007] To solve the aforementioned problems, this disclosure staggers the start timing of the period for monitoring the sum of transmission times to comply with duty cycle limits among multiple wireless modules located within the same enclosure or in very close proximity. Alternatively, it staggers the start timing of the period for monitoring the sum of transmission times among terminal groups communicating with each wireless module. The aim is to provide a wireless communication system that can avoid wireless signal collisions. [Means for solving the problem]

[0008] A first aspect of this disclosure comprises a plurality of wireless modules and control circuits, wherein the wireless modules have a function to perform wireless communication and a function to monitor the sum of the transmission times of wireless communication at regular intervals. Wireless communication is performed by continuously transmitting received traffic until the total transmission time reaches a certain period of time. The sum of the transmission times reached a certain amount of time. and others,Restrict wireless communication The received traffic is then held until the next observation period begins. It is preferable that the wireless communication device has a function, and that the control circuit has a function to determine the start timing of the observation period differently for each wireless module.

[0009] A second aspect of this disclosure is a process in which multiple wireless modules perform wireless communication and a process that monitors the sum of the transmission times of the wireless communication at regular intervals. Wireless communication is performed by continuously transmitting received traffic until the total transmission time reaches a certain period of time. The sum of the transmission times reached a certain amount of time. and others, Restrict wireless communication The received traffic is then held until the next observation period begins. Preferably, the wireless communication method includes a process, and the control circuit includes a process for determining the start timing of the observation period.

[0010] A third aspect of this disclosure is a wireless communication, which monitors the total transmission time of the wireless communication at regular intervals. Wireless communication is performed by continuously transmitting received traffic until the total transmission time reaches a certain period of time. The sum of the transmission times reached a certain amount of time. and others, Restrict wireless communication The received traffic is then held until the next observation period begins. A wireless communication system comprising multiple wireless module units and a control unit that determines the start timing of the observation period is preferable. [Effects of the Invention]

[0011] According to the first to third aspects of this disclosure, it is possible to provide a wireless communication device, a wireless communication method, and a wireless communication system that can avoid collisions of wireless signals by distributing the time periods when traffic is concentrated. [Brief explanation of the drawing]

[0012] [Figure 1] This figure shows the wireless communication timing of multiple wireless modules within the same enclosure, according to the first conventional example. [Figure 2] This figure shows the wireless communication timing of multiple wireless modules within the same enclosure, relating to the second conventional example. [Figure 3] This figure shows the configuration of the wireless communication system according to Embodiment 1 of this disclosure. [Figure 4] This diagram shows the configuration of the wireless communication repeater disclosed herein. [Figure 5] It is a diagram showing the observation period according to Embodiment 1. [Figure 6] It is a diagram showing the start timing of observation in a plurality of wireless modules according to Embodiment 1.

Embodiments for Carrying Out the Invention

[0013] Embodiment 1 Prior to the description of Embodiment 1, when communicating with a plurality of wireless modules, the problems that occurred in the conventional method will be described. First, FIG. 1 is a diagram showing the wireless communication timing by a plurality of wireless modules in the same housing according to the first conventional example. As a first conventional example in which a collision of wireless signals occurs, there is a case where the transmission timings by a plurality of wireless modules included in a repeater accidentally coincide.

[0014] Generally, in an unlicensed frequency band such as a wireless LAN, carrier sense for a fixed time + random time is required. However, if the set random times are the same, signals cannot be detected by each other's carrier sense, so even if simultaneous transmission occurs, they cannot recognize it from each other. Then, since communication proceeds as set, two transmission signals collide at the destination receiving terminal and reception fails. Note that carrier sense is a function of confirming whether a signal is being transmitted from another terminal for a fixed time + random time before transmitting a signal from one's own terminal.

[0015] FIG. 2 is a diagram showing the wireless communication timing by a plurality of wireless modules in the same housing according to the second conventional example. As a second conventional example in which a collision of wireless signals occurs, there is an interference problem caused by a hidden terminal. When the distance between the terminals relayed by a repeater is far, signals of each other cannot be detected by the carrier sense of each terminal, so even if simultaneous progress occurs, they cannot recognize it from each other. Then, since wireless transmission proceeds, when two wireless modules included in the repeater receive respectively, two transmission signals collide and reception fails.

[0016] In order to solve the above-described problems, an object of the present disclosure is to provide a wireless communication system that can avoid collisions of wireless signals by dispersing time zones in which traffic concentrates.

[0017] FIG. 3 is a diagram showing the configuration of a wireless communication system according to Embodiment 1 of the present disclosure. The wireless communication system includes a wireless communication repeater 2. The wireless communication repeater 2 has a repeater 4, which is, for example, a System On Chip (SOC). The repeater 4 relays wireless communication between wireless communication modules 6 and 8, which are wireless modules. The wireless communication modules 6 and 8 are, for example, Network Interface Controllers (NICs).

[0018] The wireless communication module 6 performs wireless communication with a wireless communication master unit 10. Also, the wireless communication module 8 performs wireless communication with a plurality of wireless communication slave units 12. When considering the wireless communication system as a plurality of terminal groups, for example, the wireless communication module 6 and the wireless communication master unit 10 are taken as terminal group 1, and the wireless communication module 8 and the plurality of wireless communication slave units 12 are taken as terminal group 2.

[0019] FIG. 4 is a diagram showing the configuration of the wireless communication repeater of the present disclosure. The wireless communication repeater 2 includes the wireless communication modules 6 and 8 as shown in FIG. 3. The wireless communication modules 6 and 8 have functions of performing wireless communication, monitoring the total transmission time of wireless transmission, and restricting wireless communication when the total transmission time reaches a certain time. Although three or more wireless communication modules may be included, the present disclosure shows a configuration including two.

[0020] [[ID=

[16] ]]The wireless communication repeater 2 includes a control circuit 14. The control circuit 14 controls the observation period and the start timing using management information according to a built-in management program.

[0021] The wireless communication repeater 2 includes a wired communication module 16. The wired communication module 16 has the function of performing wired communication and is used, for example, when performing wired communication with other repeaters. The wireless communication repeater 2 also includes a user interface 18. The user interface 18 is a module used to change the settings of the wireless communication repeater 2 from an external source and is, for example, a controller operated by the user.

[0022] The wireless communication repeater 2 is equipped with a memory 20. The memory 20 contains a control program and management information. The wireless communication repeater 2 is also equipped with a drive 22. The drive 22 has a storage medium and stores the repeater's setting information, etc. Furthermore, the wireless communication repeater 2 is equipped with a timer 24. The timer 24 measures the time related to the repeater's wireless communication.

[0023] Furthermore, the control unit of the device disclosed herein can also be implemented using a computer and a program, and the program can be recorded on a recording medium or provided via a network.

[0024] Figure 5 shows the observation period according to Embodiment 1. In the wireless communication modules 6 and 8 according to Embodiment 1, the total transmission time of wireless transmissions is monitored to ensure that the transmission time during a certain observation period 26 is less than or equal to a certain time in order to limit the total transmission time of wireless transmissions.

[0025] The duty limit is a restriction on the total transmission time, which is legally defined as "the sum of transmission times not exceeding 360 seconds per hour." For example, in the 920MHz band in Japan, a 10% duty limit is imposed, so the sum of transmission time of wireless communication terminals is limited to within 360 seconds per hour. This duty limit is imposed on the premise that wireless communication terminals are equipped with a function to monitor and limit the total transmission time in that band.

[0026] To comply with duty cycle limits, it is more practical to monitor in units of observation periods that can be implemented on the terminal, rather than monitoring the entire sum of transmission time over an hour. For example, monitoring to ensure that the sum of transmission time is within 100 msec for a 1-second observation period, and repeating this process, allows compliance with the 10% duty cycle limit even over long periods such as an hour.

[0027] Figure 6 shows the start timing of observations in multiple wireless modules according to Embodiment 1. Here, when using two wireless modules, an observation period 26 is set in order to limit the total transmission time in order to comply with duty cycle limits.

[0028] As a means of solving the problem in this disclosure, the start timing of the observation period 26 is staggered among multiple wireless modules within the same housing in order to avoid collisions of wireless signals. Specifically, the control circuit 14 determines how much to stagger the start timing of the observation period 26 and transmits this to the wireless communication modules 6 and 8, thereby controlling the start timing of the observation period 26. When the traffic load is heavy relative to the duty cycle limit, it is conceivable that transmissions will be concentrated from the start timing of the period for monitoring the total transmission time until the time limit defined by the duty cycle. By utilizing this and staggering the start timing, the time period in which transmissions are concentrated is distributed among terminals or groups of terminals.

[0029] Let me explain in more detail why the traffic load can be distributed. Ideally, we would like to transmit traffic at all times, but due to duty cycle limitations, it can only be transmitted for a limited percentage of the observation period 26. As a result, traffic is transmitted as much as possible immediately after the start of the observation period 26, and transmission is interrupted once the time limit is exceeded. This state is the traffic concentration 28 shown in Figure 6. By shifting the start timing of the observation period 26, this traffic concentration 28 can be distributed, thereby avoiding signal collisions between wireless modules.

[0030] For example, if the observation period is 1 second, the start timing of the observation period for each wireless module is shifted by 500 msec. For example, as shown in Figure 6, if the observation period 26 is 1 second, the time from T1-1 to T2-1 is set to 500 msec. If the duty limit is 10%, the limit on the total transmission time is 100 msec. Even considering the overhead for access control, the traffic concentration 28 with a high traffic load will only continue for the first 150 msec or so from the start timing. In other words, the total transmission time will be used up during this period, and transmission will be impossible for the remaining 850 msec. Therefore, even if the observation period of another wireless module or terminal group starts at a timing shifted by 500 msec, the wireless signals will not collide.

[0031] Alternatively, the start timing of the observation period 26 is synchronized within a terminal group that includes terminals communicating with each wireless module, while the start timing of the observation period 26 is staggered between different terminal groups. This allows for the dispersion of traffic concentration times 28, even if terminals are hidden from each other, thereby avoiding signal collisions between terminal groups. [Explanation of Symbols]

[0032] 14 Control circuits 26. Observation period

Claims

1. Equipped with multiple wireless modules and control circuits, The aforementioned wireless module The function of performing wireless communication, A function to monitor the total transmission time of the aforementioned wireless communication at regular intervals, The wireless communication is performed by transmitting the received traffic as it is received until the sum of the transmission times reaches a certain period of time, and once the sum of the transmission times reaches the certain period of time, the wireless communication is restricted and the received traffic is held until the next observation period begins. The control circuit has a function to determine the start timing of the observation period to differ for each wireless module. Wireless communication device.

2. Equipped with two of the aforementioned wireless modules, The start timing of the observation period for one wireless module is the timing when half of the observation period for the other wireless module has elapsed. The wireless communication device according to claim 1.

3. Multiple wireless modules, The process of performing wireless communication, A process to monitor the total transmission time of the aforementioned wireless communication at regular intervals, The wireless communication is performed by transmitting the received traffic as it is received until the sum of the transmission times reaches a certain period of time, and once the sum of the transmission times reaches the certain period of time, the wireless communication is restricted and the received traffic is held until the next observation period begins. The control circuit includes a process for determining the start timing of the observation period. Wireless communication method.

4. Equipped with two of the aforementioned wireless modules, The start timing of the observation period for one wireless module is the timing when half of the observation period for the other wireless module has elapsed. The wireless communication method according to claim 3.

5. The start timing of the observation period is determined to be different for each wireless module included in the same terminal group. The wireless communication method according to claim 3.

6. Wireless communication is performed, The sum of the transmission times of the aforementioned wireless communication is monitored at regular intervals. The wireless communication is performed by transmitting the received traffic as it is received until the sum of the transmission times reaches a certain period of time. Once the sum of the transmission times reaches the certain period of time, the wireless communication is restricted and the received traffic is held until the next observation period begins. Multiple wireless module units, A control unit that determines the start timing of the observation period. A wireless communication system equipped with [the following features].

7. The system is equipped with two of the aforementioned wireless module units. The start timing of the observation period for one wireless module is the timing when half of the observation period for the other wireless module has elapsed. The wireless communication system according to claim 6.

8. The start timing of the aforementioned observation period is determined to differ for each wireless module unit included in the same terminal group. The wireless communication system according to claim 6.

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