WO2023203689A1

WO2023203689A1 - Wireless communication system, wireless communication control method, and base station

Info

Publication number: WO2023203689A1
Application number: PCT/JP2022/018310
Authority: WO
Inventors: 純一岩谷; 笑子篠原; 裕介淺井; 泰司鷹取; 知之山田; 芳孝清水
Original assignee: 日本電信電話株式会社
Priority date: 2022-04-20
Filing date: 2022-04-20
Publication date: 2023-10-26

Abstract

This wireless communication system comprises: a wireless terminal that comprises a plurality of wireless modules for performing wireless communication in channels differing from one another; a base station that performs wireless communication with the plurality of wireless modules; and a plurality of relay devices that relay the wireless communication between the base station and each of the plurality of wireless modules. The wireless terminal uses one of the plurality of wireless modules as a usage module and stops data transmission from wireless modules other than the usage module. The base station determines a usage schedule for each of the plurality of wireless modules such that the transmission time ratio of each of the plurality of wireless modules of the wireless terminal does not exceed a prescribed upper limit. In addition, the base station notifies each wireless module of information relating to the determined usage schedule. Each wireless module operates as the usage module in accordance with the usage schedule determined by the base station.

Description

Wireless communication system, wireless communication control method, and base station

The present invention relates to a technology for controlling a wireless terminal that performs wireless communication by switching between multiple channels.

Wireless communication systems including base stations and wireless terminals are known. A typical example of a wireless communication system is a public wireless LAN (Local Area Network). In a wireless LAN for public use, for example, a use case is assumed in which data is transmitted from a base station to a wireless terminal such as a computer terminal or a smartphone terminal. Furthermore, with the spread of IoT (Internet of Things) terminals in recent years, use cases for transmitting data from a wireless terminal to a base station are increasing.

In connection with wireless communication for IoT, the use of unlicensed Sub-1 GHz band has been institutionalized in various countries around the world (see Non-Patent Document 1). In Japan, the 920 MHz band is allocated as a frequency band for electronic tag systems. For example, LPWA (Low Power Wide Area) wireless communication systems such as LoRa (registered trademark) and WiSUN (registered trademark) are known as active electronic tag systems. Furthermore, the use of IEEE 802.11ah, which is one of the wireless LAN standards, is also being considered.

Since the number of frequency channels is limited in the 920 MHz band, there may be cases where wireless communication is performed while changing the channel to be used.

For example, in Japan, there is a limit on the total transmission time when using the 920 MHz band, and the total transmission time per hour must be within 360 seconds. Because the wireless communication device limits data transmission to comply with this total transmission time limit, throughput is also limited. However, for a case of a wireless communication device that switches between two non-overlapping channels, a total transmission time of up to 360 seconds for each channel per hour, or 720 seconds in total, is allowed. Therefore, in order to improve throughput, it is conceivable to perform wireless communication while changing the channel used by the housing of the wireless communication device.

Consider the case where a wireless terminal transmits data to a base station via a relay device. In situations where there is a restriction on the transmission time rate for each channel, throughput can be improved by switching the channel used by a wireless terminal. However, complicated processing is required to switch the channel used within the wireless module included in the wireless terminal.

One object of the present invention is to provide a technology that can simplify the process of switching channels used by a wireless terminal.

The first aspect relates to wireless communication systems.
The wireless communication system is
a wireless terminal including a plurality of wireless modules that perform wireless communication on mutually different channels;
A base station that performs wireless communication with multiple wireless modules,
A plurality of relay devices that relay wireless communication between each of the plurality of wireless modules and a base station are provided.
The wireless terminal uses one of the plurality of wireless modules as a used module, and stops data transmission from wireless modules other than the used module.
The base station is
determining a usage schedule for each of the plurality of wireless modules so that the transmission time rate of each of the plurality of wireless modules of the wireless terminal does not exceed a predetermined upper limit;
It is configured to notify the wireless terminal of usage schedule information.
Each of the plurality of wireless modules operates as a usage module according to a usage schedule determined by the base station.

The second aspect relates to a wireless communication control method that controls wireless communication between a wireless terminal and a base station via a plurality of relay devices.
A wireless terminal includes a plurality of wireless modules that perform wireless communication using different channels, uses one of the wireless modules as a used module, and stops data transmission from wireless modules other than the used module.
The plurality of relay devices relay wireless communication between each of the plurality of wireless modules and the base station.
The wireless communication control method is
In the base station, determining a usage schedule for each of the plurality of wireless modules such that the transmission time rate of each of the plurality of wireless modules of the wireless terminal does not exceed a predetermined upper limit;
Notifying usage schedule information from a base station to a wireless terminal;
and operating each of the plurality of wireless modules as a usage module according to a usage schedule determined by the base station.

The third aspect relates to a base station that performs wireless communication with wireless terminals via a plurality of relay devices.
A wireless terminal includes a plurality of wireless modules that perform wireless communication using different channels, uses one of the wireless modules as a used module, and stops data transmission from wireless modules other than the used module.
The plurality of relay devices relay wireless communication between each of the plurality of wireless modules and the base station.
The base station includes a control unit.
The control section is
determining a usage schedule for each of the plurality of wireless modules so that the transmission time rate of each of the plurality of wireless modules of the wireless terminal does not exceed a predetermined upper limit;
The information on the usage schedule is notified to the wireless terminal, and each of the plurality of wireless modules is configured to operate as a usage module according to the usage schedule.

According to the present invention, a wireless terminal includes a plurality of wireless modules that perform wireless communication using mutually different channels. By switching the module in use among a plurality of wireless modules, the channel used for wireless communication can be easily changed. Since there is no need to switch channels within a single wireless module, it is possible to simplify the processing required for channel switching.

FIG. 1 is a block diagram showing the basic configuration of a wireless communication system according to an embodiment. 3 is a timing chart for explaining an overview of data transmission control involving module switching processing according to an embodiment. FIG. 2 is a block diagram for explaining an overview of a control unit according to an embodiment. It is a block diagram showing an example of composition of a control part concerning an embodiment. 1 is a block diagram showing a configuration example of a wireless communication system according to an embodiment. FIG. 2 is a conceptual diagram for explaining a first processing example by a control unit according to an embodiment. 5 is a timing chart for explaining a first processing example by a control unit according to an embodiment. 7 is a flowchart illustrating a first processing example by the control unit according to the embodiment. FIG. 7 is a conceptual diagram for explaining a second example of processing by the control unit according to the embodiment. 7 is a timing chart for explaining a second example of processing by the control unit according to the embodiment. 7 is a flowchart illustrating a second example of processing by the control unit according to the embodiment. FIG. 7 is a conceptual diagram for explaining a third example of processing by the control unit according to the embodiment. It is a flowchart which shows the 3rd example of processing by a control part concerning an embodiment.

Embodiments of the present invention will be described with reference to the accompanying drawings.

1. Overview of wireless communication system 1-1. Basic Configuration FIG. 1 is a block diagram showing the basic configuration of a wireless communication system 1 according to the present embodiment. The wireless communication system 1 includes a wireless terminal 10, a base station 20, and a plurality of relay devices 30. The wireless terminal 10 and the base station 20 perform wireless communication with each other via the relay device 30. In other words, relay device 30 relays wireless communication between wireless terminal 10 and base station 20. The relay device 30 also makes it possible to accommodate wireless terminals 10 that are far away from the base station 20. For example, the wireless communication system 1 is a wireless LAN system. For example, the wireless communication system 1 performs wireless communication using the unlicensed Sub-1 GHz band. For example, the wireless communication system 1 performs wireless communication using the 920 MHz band.

The wireless terminal 10 according to the present embodiment can perform wireless communication by switching between multiple channels (frequency channels). More specifically, the wireless terminal 10 includes a plurality of wireless modules 11 that perform wireless communication using different channels that do not overlap with each other. Each wireless module 11 includes, for example, a network interface controller (network interface card). The plurality of wireless modules 11 are each connected to the plurality of relay devices 30. That is, the plurality of wireless modules 11 perform wireless communication with the single base station 20 via each of the plurality of relay devices 30. In other words, the plurality of relay devices 30 relay wireless communication between each of the plurality of wireless modules 11 and the single base station 20.

In the example shown in FIG. 1, the wireless terminal 10 includes a first wireless module 11-1 and a second wireless module 11-2. The first wireless module 11-1 is set to perform wireless communication on the first channel CH-1. The first wireless module 11-1 is connected to the first relay device 30-1 and performs wireless communication with the base station 20 via the first relay device 30-1 on the first channel CH-1. On the other hand, the second wireless module 11-2 is set to perform wireless communication on a second channel CH-2 that does not overlap with the first channel CH-1. The second wireless module 11-2 is connected to the second relay device 30-2 and performs wireless communication with the base station 20 via the second relay device 30-2 on the second channel CH-2.

1-2. Module Switching Process By switching the wireless module 11 used by the wireless terminal 10, the channel used for wireless communication can be easily switched. One of the plurality of wireless modules 11 that is selectively used is hereinafter referred to as a "used module 11S." The usage module 11S can also be called a "selection module". Further, the process of switching the used module 11S in the wireless terminal 10 will be referred to as "module switching process" hereinafter.

The wireless terminal 10 uses one of the plurality of wireless modules 11 as the module 11S to transmit data. More specifically, the wireless terminal 10 includes a plurality of wireless modules 11, as well as an upper layer 12 and a selector 13. The selector 13 receives transmission data from the upper layer 12 and outputs the transmission data to the usage module 11S. The selector 13 does not send the transmission data to any wireless module 11 other than the used module 11S. The used module 11S transmits transmission data from the upper layer 12, and the wireless modules 11 other than the used module 11S stop data transmission.

Next, consider a situation where there is a restriction (upper limit) on the transmission time rate for each channel used by the wireless terminal 10. For example, in Japan, there is a limit on the total transmission time when using the 920 MHz band, and the total transmission time per hour must be within 360 seconds. For a case that switches between two non-overlapping channels, a total transmission time of 360 seconds for each channel per hour, for a total of 720 seconds, is allowed. Therefore, in order to improve throughput, module switching processing that switches the module 11S used in the wireless terminal 10 is effective.

FIG. 2 is a timing chart for explaining an overview of data transmission control accompanied by module switching processing according to the present embodiment. Here, switching between the first wireless module 11-1 (first channel CH-1) and the second wireless module 11-2 (second channel CH-2) will be considered.

During the period from time t1 to time t2, the first wireless module 11-1 is selected as the module to be used 11S. Data transmission from the first wireless module 11-1 is permitted, but data transmission from the second wireless module 11-2 is prohibited. That is, the period from time t1 to t2 is a transmission permission period PA for the first wireless module 11-1, and a transmission prohibition period PB for the second wireless module 11-2. The wireless terminal 10 uses the first wireless module 11-1 as the usage module 11S, and performs wireless communication with the base station 20 on the first channel CH-1 via the first relay device 30-1. On the other hand, the wireless terminal 10 stops data transmission from the second wireless module 11-2.

At time t2, the wireless terminal 10 switches the module 11S in use from the first wireless module 11-1 to the second wireless module 11-2.

During the period from time t2 to time t3, the second wireless module 11-2 is selected as the module to be used 11S. Data transmission from the second wireless module 11-2 is permitted, but data transmission from the first wireless module 11-1 is prohibited. That is, the period from time t2 to t3 is a transmission prohibited period PB for the first wireless module 11-1, and a transmission permitted period PA for the second wireless module 11-2. The wireless terminal 10 uses the second wireless module 11-2 as the usage module 11S, and performs wireless communication with the base station 20 on the second channel CH-2 via the second relay device 30-2. On the other hand, the wireless terminal 10 stops data transmission from the first wireless module 11-1.

At time t3, the wireless terminal 10 switches the module 11S in use from the second wireless module 11-2 to the first wireless module 11-1. The period from time t3 to t4 is the same as the period from time t1 to t2.

The transmission permission period PA does not overlap between the first wireless module 11-1 and the second wireless module 11-2. Furthermore, the transmission prohibition period PB does not overlap between the first wireless module 11-1 and the second wireless module 11-2.

Note that the transmission time rate of each wireless module 11 can be calculated from the transmission time of each wireless module 11 in the measurement period PM.

In order to realize the module switching process described above, the wireless communication system 1 according to the present embodiment includes a "control unit 100" that manages and controls the module switching process.

FIG. 3 is a block diagram for explaining an overview of the control unit 100. The control unit 100 monitors and manages the transmission time and transmission time rate of each of the plurality of wireless modules 11 (multiple channels) of the wireless terminal 10 . Then, the control unit 100 determines a usage schedule for each of the plurality of wireless modules 11 so that the transmission time rate of each of the plurality of wireless modules 11 of the wireless terminal 10 does not exceed a predetermined upper limit. For example, the usage schedule includes a transmission permission period PA assigned to each wireless module 11. The usage schedule can also be called transmission timing. Although various examples can be considered as triggers for module switching processing, the usage schedule is determined so that at least the transmission time rate of each wireless module 11 does not exceed a predetermined upper limit.

Furthermore, the control unit 100 controls the wireless terminal 10 to perform module switching processing according to the determined usage schedule. That is, the control unit 100 controls the wireless terminal 10 to switch the usage module 11S according to the determined usage schedule. The wireless terminal 10 switches the usage module 11S according to the usage schedule determined by the control unit 100. Each wireless module 11 operates as a usage module 11S according to the usage schedule determined by the control unit 100.

1-3. Effects As described above, according to the present embodiment, the wireless terminal 10 includes a plurality of wireless modules 11 that perform wireless communication using mutually different channels. By switching the used module 11S between the plurality of wireless modules 11, the channel used for wireless communication can be easily changed. Since there is no need to switch channels within a single wireless module 11, it is possible to simplify the processing required for channel switching. Furthermore, since restarting the wireless terminal 10 is not required for channel switching, communication interruption time is reduced and service quality is prevented from deteriorating.

Furthermore, according to the present embodiment, the control unit 100 determines the usage schedule of each wireless module 11 so that the transmission time rate of each wireless module 11 of the wireless terminal 10 does not exceed a predetermined upper limit. Since the control unit 100 accurately manages the transmission time rate of each wireless module 11, it is possible to use each channel up to the upper limit of the transmission time rate. That is, it becomes possible to expand the transmission time rate of the wireless terminal 10 as a whole and effectively improve throughput.

Furthermore, according to this embodiment, since the wireless terminal 10 includes a plurality of wireless modules 11, redundancy is ensured and reliability is improved.

Furthermore, according to this embodiment, the relay device 30 also makes it possible to accommodate a wireless terminal 10 that is far away from the base station 20.

2. Configuration Example of Control Unit FIG. 4 is a block diagram showing a configuration example of the control unit 100 according to the present embodiment. In the example shown in FIG. 4, the control unit 100 includes one or more processors 110 (hereinafter simply referred to as "processors 110") and one or more storage devices 120 (hereinafter simply referred to as "storage devices 120"). It is a computer equipped with. For example, processor 110 includes a CPU (Central Processing Unit). The storage device 120 stores various information necessary for processing by the processor 110. Examples of the storage device 120 include volatile memory, nonvolatile memory, HDD (Hard Disk Drive), SSD (Solid State Drive), and the like.

The control program 130 is a computer program executed by the processor 110. The functions of the control unit 100 are realized by the processor 110 executing the control program 130. Control program 130 is stored in storage device 120. The control program 130 may be recorded on a computer-readable recording medium. The control program 130 may be provided to the control unit 100 via a network.

Module switching management information 200 is stored in the storage device 120. Module switching management information 200 is information for managing module switching processing. For example, the module switching management information 200 includes the transmission time and transmission time rate of each of the plurality of wireless modules 11 of the wireless terminal 10. The module switching management information 200 may include a usage schedule for each of the plurality of wireless modules 11. For example, the usage schedule includes a transmission permission period PA (eg, a combination of start time and duration) assigned to each wireless module 11. The usage schedule can also be called transmission timing.

The storage device 120 may further store relay device status information 300. Relay device status information 300 indicates the status of each relay device 30 connected to base station 20. Relay device status information 300 includes identification information of each relay device 30. Further, the relay device status information 300 includes information (number, etc.) of the wireless terminals 10 and wireless modules 11 under each relay device 30. As another example, the relay device status information 300 may include the distance between each relay device 30 and the subordinate wireless terminal 10. As yet another example, the relay device status information 300 may include the traffic status and transmission time rate of each relay device 30. As yet another example, the relay device status information 300 may include the used channel and transmission power of each relay device 30. The control unit 100 communicates with each relay device 30 and acquires relay device status information 300 from each relay device 30.

3. Processing example when the base station includes a control unit It is complicated and inefficient for the wireless terminal 10 itself to manage the transmission time rate of each wireless module 11 and determine the usage schedule of each wireless module 11. Therefore, below, a case where the base station 20 includes the control unit 100 will be considered.

FIG. 5 is a block diagram showing a configuration example of the wireless communication system 1 when the base station 20 includes the control unit 100. Since the base station 20 includes the control unit 100, it becomes possible to efficiently determine the usage schedule of each wireless module 11 of each wireless terminal 10. Moreover, complicated processing in the wireless terminal 10 is not necessary.

Hereinafter, the processing in the wireless communication system 1 shown in FIG. 5 will be described in detail.

3-1. First Processing Example FIG. 6 is a conceptual diagram for explaining a first processing example by the control unit 100 included in the base station 20. FIG. 7 is a timing chart for explaining a first processing example by the control unit 100 included in the base station 20.

The control unit 100 monitors the transmission time and transmission time rate of each of the plurality of wireless modules 11 of the wireless terminal 10, and updates the module switching management information 200 (see FIG. 4). Further, the control unit 100 determines a usage schedule for each of the plurality of wireless modules 11. For example, the control unit 100 basically determines the usage schedule of each wireless module 11 so that the usage module 11S is switched at regular intervals. However, the control unit 100 determines the usage schedule of each wireless module 11 based on the module switching management information 200 so that the transmission time rate of each wireless module 11 does not exceed a predetermined upper limit. Although the trigger for the module switching process is arbitrary, the usage schedule is determined so that at least the transmission time rate of each wireless module 11 does not exceed a predetermined upper limit.

The usage schedule includes a transmission permission period PA assigned to each wireless module 11, that is, a transmission permission period PA during which each wireless module 11 operates as a usage module 11S. The transmission permission period PA is defined, for example, by a combination of a start time and a duration. The transmission permission period PA is set so as not to overlap among the plurality of wireless modules 11.

The control unit 100 instructs the wireless terminal 10 to switch the usage module 11S according to the determined usage schedule. More specifically, the control unit 100 generates schedule information SKD indicating the determined usage schedule, and notifies the wireless terminal 10 of the schedule information SKD. Each of the plurality of wireless modules 11 operates as a usage module 11S according to a usage schedule determined by the control unit 100. That is, the wireless terminal 10 switches the usage module 11S according to the usage schedule determined by the control unit 100.

In the examples shown in FIGS. 6 and 7, the first wireless module 11-1 and the second wireless module 11-2 of the wireless terminal 10 are connected to the first relay device 30-1 and the second relay device 30-2, respectively. It is connected.

The control unit 100 determines a usage schedule regarding the first wireless module 11-1. At this time, the control unit 100 determines the usage schedule of the first wireless module 11-1 based on the module switching management information 200 so that the transmission time rate of the first wireless module 11-1 does not exceed a predetermined upper limit. do. Then, the control unit 100 transmits first schedule information SKD-1 regarding the usage schedule of the first wireless module 11-1 to the first relay device 30-1 connected to the first wireless module 11. The first relay device 30-1 receives the first schedule information SKD-1 and transmits the first schedule information SKD-1 to the first wireless module 11-1. That is, the control unit 100 notifies the first schedule information SKD-1 to the first wireless module 11-1 via the first relay device 30-1. At this time, TWT (Target Wake Time) may be used. The first wireless module 11-1 operates as the usage module 11S according to the first schedule information SKD-1 determined by the control unit 100. That is, the first wireless module 11-1 operates as the usage module 11S during the transmission permission period PA determined by the control unit 100. The first relay device 30-1 relays wireless communication between the base station 20 and the first wireless module 11-1 according to the first schedule information SKD-1.

Additionally, the control unit 100 determines a usage schedule regarding the second wireless module 11-2. At this time, the control unit 100 determines the usage schedule of the second wireless module 11-2 based on the module switching management information 200 so that the transmission time rate of the second wireless module 11-2 does not exceed a predetermined upper limit. do. Then, the control unit 100 transmits second schedule information SKD-2 regarding the usage schedule of the second wireless module 11-2 to the second relay device 30-2 connected to the second wireless module 11. The second relay device 30-2 receives the second schedule information SKD-2 and transmits the second schedule information SKD-2 to the second wireless module 11-2. That is, the control unit 100 notifies the second wireless module 11-2 of the second schedule information SKD-2 via the second relay device 30-2. At this time, TWT may be used. The second wireless module 11-2 operates as the usage module 11S according to the second schedule information SKD-2 determined by the control unit 100. That is, the second wireless module 11-2 operates as the usage module 11S during the transmission permission period PA determined by the control unit 100. The second relay device 30-2 relays wireless communication between the base station 20 and the second wireless module 11-2 according to the second schedule information SKD-2.

The control unit 100 may also consider the timing of downlink traffic from the base station 20 and determine the schedule to match the timing of downlink traffic from the base station 20.

During communication, the control unit 100 may update the usage schedule of each wireless module 11. For example, the control unit 100 grasps the communication quality and traffic situation of the base station 20. The traffic situation may include the transmission time rate of the base station 20. The control unit 100 updates the usage schedule of each wireless module 11 based on the communication quality and traffic situation of the base station 20. Then, the control unit 100 notifies the wireless module 11 of schedule information SKD indicating the updated usage schedule.

FIG. 8 is a flowchart showing a first processing example by the control unit 100 included in the base station 20.

In step S110, the control unit 100 determines whether a connection state update notification has been received from any relay device 30. The connection state update notification is a notification indicating that the connection state between the relay device 30 and the wireless terminal 10 (wireless module 11) has been updated. If a connection state update notification is received (step S110; Yes), the process proceeds to step S111.

In step S111, the control unit 100 determines a usage schedule for each wireless module 11 under the relay device 30. At this time, the usage schedule of each wireless module 11 is determined so that the transmission permission periods PA do not overlap among the multiple wireless modules 11.

In step S112, the control unit 100 notifies the corresponding wireless module 11 of schedule information SKD indicating the usage schedule via the relay device 30.

According to the first processing example, the control unit 100 determines the usage schedule of each wireless module 11 so that the transmission time rate of each wireless module 11 of the wireless terminal 10 does not exceed a predetermined upper limit. Since the control unit 100 accurately manages the transmission time rate of each wireless module 11, it is possible to use each channel up to the upper limit of the transmission time rate. That is, it becomes possible to expand the transmission time rate of the wireless terminal 10 as a whole and effectively improve throughput.

Furthermore, since the base station 20 includes the control unit 100, it is possible to efficiently determine the usage schedule of each wireless module 11 of each wireless terminal 10. Moreover, complicated processing in the wireless terminal 10 is not necessary.

3-2. Second Processing Example In the second processing example, the connection process between the wireless module 11 and the relay device 30 will be considered in particular. When the wireless module 11 connects to the relay device 30, it is assumed that a plurality of relay devices 30 exist as connection destination candidates. In this case, the control unit 100 specifies the optimal one from among the plurality of relay devices 30 (connection destination candidates).

More specifically, the control unit 100 constantly monitors the status of each relay device 30 connected to the base station 20 and updates the relay device status information 300 (see FIG. 4). For example, the relay device status information 300 includes information on the wireless terminals 10 and wireless modules 11 under each relay device 30. As another example, the relay device status information 300 includes the traffic status of each relay device 30 and the transmission time rate as a relay device.

The control unit 100 sets the priority of each relay device 30 based on the relay device status information 300. For example, the control unit 100 grasps the congestion status of the relay device 30 based on the available bandwidth, the number of connected terminals, and the like. Then, the control unit 100 lowers the priority of the relay device 30 with less available radio resources. As another example, if there is also a restriction on the transmission time rate regarding the downlink traffic from the relay device 30 to the wireless terminal 10, the control unit 100 grasps the current status of the downlink traffic and the transmission time rate. Then, the control unit 100 lowers the priority of the relay device 30 with less margin in the transmission time rate. Then, the control unit 100 selects a relay device 30 to which the wireless module 11 is connected according to the priority of each relay device 30.

A second processing example will be described with reference to FIGS. 9 and 10. In the example shown in FIGS. 9 and 10, the base station 20 is connected to a first relay device 30-1, a second relay device 30-2, and a third relay device 30-3.

The first wireless module 11-1 of the wireless terminal 10 transmits a connection destination inquiry INQ to the nearby relay device 30. Upon receiving the connection destination inquiry INQ, each relay device 30 transmits a connection destination inquiry notification NTF to the control unit 100. In response to the connection destination inquiry notification NTF, the control unit 100 selects the connection destination of the first wireless module 11-1 from among the relay devices 30 that are not connected to other wireless modules 11. At this time, the control unit 100 sets the priority of each relay device 30 based on the relay device status information 300, and selects the connection destination of the first wireless module 11-1 according to the priority. Here, for example, the first relay device 30-1 has the highest priority and is selected. The control unit 100 instructs the selected first relay device 30-1 to respond to the first wireless module 11-1. According to the instruction from the control unit 100, the first relay device 30-1 returns a response RES to the first wireless module 11-1, which is the connection destination inquiry source. As a result, connection processing is performed between the first wireless module 11-1 and the first relay device 30-1.

Thereafter, the second wireless module 11-2 of the wireless terminal 10 transmits a connection destination inquiry INQ to the nearby relay device 30. Upon receiving the connection destination inquiry INQ, each relay device 30 transmits a connection destination inquiry notification NTF to the control unit 100. In response to the connection destination inquiry notification NTF, the control unit 100 selects the connection destination of the second wireless module 11-2 from among the relay devices 30 that are not connected to other wireless modules 11. At this time, the control unit 100 sets the priority of each relay device 30 based on the relay device state information 300, and selects the connection destination of the second wireless module 11-2 according to the priority. Here, for example, the second relay device 30-2 has the highest priority and is selected. The control unit 100 instructs the selected second relay device 30-2 to respond to the second wireless module 11-2. According to the instruction from the control unit 100, the second relay device 30-2 returns a response RES to the second wireless module 11-2, which is the connection destination inquiry source. As a result, connection processing is performed between the second wireless module 11-2 and the second relay device 30-2.

FIG. 11 is a flowchart showing a second example of processing by the control unit 100 included in the base station 20.

In step S120, the control unit 100 determines whether a connection destination inquiry notification NTF has been received from at least one relay device 30. The connection destination inquiry notification NTF is a notification indicating that the relay device 30 has received the connection destination inquiry INQ from the wireless module 11. If the connection destination inquiry notification NTF is received (step S120; Yes), the process proceeds to step S121.

In step S121, the control unit 100 sets the priority of each relay device 30 based on the relay device status information 300. Then, the control unit 100 selects one relay device 30 to which the wireless module 11 is connected based on the priority of each relay device 30.

In step S122, the control unit 100 instructs the selected relay device 30 to respond to the wireless module 11 that is the connection destination inquiry source.

As explained above, according to the second processing example, it is possible to appropriately select the connection destination of the wireless module 11 according to the state of the relay device 30 (traffic, transmission time rate, etc.). Become. By combining the first processing example and the second processing example described above, it is possible to further efficiently improve throughput.

3-3. Third Processing Example FIG. 12 is a conceptual diagram for explaining a third processing example by the control unit 100 included in the base station 20. In the third processing example, the control unit 100 determines at least one of the channel used and the transmission power of each relay device 30.

More specifically, the control unit 100 constantly monitors the status of each of the multiple relay devices 30 connected to each of the multiple wireless modules 11, and updates the relay device status information 300 (see FIG. 4). For example, the relay device status information 300 includes information on the wireless terminals 10 and wireless modules 11 under each relay device 30. As another example, the relay device status information 300 includes the distance between each relay device 30 and the subordinate wireless terminal 10. As yet another example, the relay device status information 300 includes the traffic status and used channels of each relay device 30.

The control unit 100 determines at least one of the channel used and the transmission power of each relay device 30 based on the relay device status information 300. For example, the control unit 100 increases the transmission power of the relay device 30 as the distance between the relay device 30 and the subordinate wireless terminal 10 increases. As another example, the control unit 100 may determine the channels used by each relay device 30 so that the channels used do not overlap among the plurality of relay devices 30. As still another example, the control unit 100 may determine the channel to be used by each relay device 30 based on the communication state and communication quality between the base station 20 and each relay device 30.

The control unit 100 instructs each relay device 30 to operate according to the determined usage channel/transmission power. More specifically, the control unit 100 generates relay device control information CON indicating the used channel/transmission power determined for each relay device 30. Then, the control unit 100 notifies each relay device 30 of the relay device control information CON. Each relay device 30 operates according to the used channel/transmission power indicated by the relay device control information CON.

For example, the control unit 100 generates first relay device control information CON-1 indicating the used channel/transmission power determined for the first relay device 30-1. Then, the control unit 100 notifies the first relay device 30-1 of the first relay device control information CON-1. The first relay device 30-1 operates according to the used channel/transmission power indicated by the first relay device control information CON-1. The same applies to the second relay device 30-2.

FIG. 13 is a flowchart showing a third example of processing by the control unit 100 included in the base station 20.

In step S130, the control unit 100 determines whether a connection state update notification has been received from any relay device 30. The connection state update notification is a notification indicating that the connection state between the relay device 30 and the wireless terminal 10 (wireless module 11) has been updated. If a connection status update notification is received (step S130; Yes), the process proceeds to step S131.

In step S131, the control unit 100 determines at least one of the channel used and the transmission power of the relay device 30 based on the relay device state information 300.

In step S132, the control unit 100 instructs the relay device 30 to operate according to the determined usage channel/transmission power.

According to the third processing example, it is possible to improve communication quality by controlling the transmission power of the relay device 30 and the channels used.

3-4. Fourth Processing Example A combination of two or more of the first to third processing examples described above is also possible. For example, a combination of the first, second, and third processing examples is also possible.

1...Wireless communication system, 10...Wireless terminal, 11...Wireless module 11, 11-1...First wireless module, 11-2...Second wireless module, 11S...Using module, 12...Upper layer, 13...Selector, 20 ...Base station, 30...Relay device, 30-1...First relay device, 30-2...Second relay device, 100...Control unit, 110...Processor, 120...Storage device, 130...Control program, 200...Module switching Management information, 300...Relay device status information, CON...Relay device control information, INQ...Connection destination inquiry, NTF...Connection destination inquiry notification, PA...Transmission permission period, PB...Transmission prohibition period, SKD...Schedule information

Claims

a wireless terminal including a plurality of wireless modules that perform wireless communication on mutually different channels;
a base station that performs wireless communication with the plurality of wireless modules;
a plurality of relay devices that relay the wireless communication between each of the plurality of wireless modules and the base station,
The wireless terminal uses one of the plurality of wireless modules as a used module, and stops data transmission from wireless modules other than the used module,
The base station is
determining a usage schedule for each of the plurality of wireless modules such that a transmission time rate of each of the plurality of wireless modules of the wireless terminal does not exceed a predetermined upper limit;
configured to notify information of the usage schedule to the wireless terminal,
Each of the plurality of wireless modules operates as the usage module according to the usage schedule determined by the base station. The wireless communication system.
The wireless communication system according to claim 1,
The plurality of wireless modules include a first wireless module,
The plurality of relay devices include a first relay device connected to the first wireless module,
The base station determines the usage schedule regarding the first wireless module, and notifies the first wireless module of information on the usage schedule regarding the first wireless module via the first relay device;
the first wireless module operates as the usage module according to the usage schedule for the first wireless module;
The first relay device relays the wireless communication between the base station and the first wireless module. A wireless communication system.
The wireless communication system according to claim 2,
The usage schedule regarding the first wireless module includes a transmission permission period during which the first wireless module operates as the usage module,
The first wireless module operates as the usage module during the transmission permission period determined by the base station.
The wireless communication system according to claim 1,
The plurality of wireless modules include a first wireless module,
The base station further includes:
retaining relay device status information indicating the status of each relay device connected to the base station;
When there is a connection destination inquiry from the first wireless module, selecting a first relay device as a connection destination of the first wireless module based on the relay device status information;
configured to instruct the selected first relay device to respond to the first wireless module;
The first wireless module connects to the first relay device selected by the base station. A wireless communication system.
The wireless communication system according to claim 1,
The base station further includes:
retaining relay device status information indicating the status of each of the plurality of relay devices;
determining at least one of a used channel and transmission power of each of the plurality of relay devices based on the relay device state information;
A wireless communication system configured to instruct each of the relay devices to operate according to at least one of the determined channel to be used and the determined transmission power.
A wireless communication control method for controlling wireless communication between a wireless terminal and a base station via a plurality of relay devices, the method comprising:
The wireless terminal includes a plurality of wireless modules that perform wireless communication on mutually different channels, uses one of the plurality of wireless modules as a used module, and stops data transmission from wireless modules other than the used module. ,
The plurality of relay devices relay the wireless communication between each of the plurality of wireless modules and the base station,
The wireless communication control method includes:
In the base station, determining a usage schedule for each of the plurality of wireless modules so that a transmission time rate of each of the plurality of wireless modules of the wireless terminal does not exceed a predetermined upper limit;
Notifying information of the usage schedule from the base station to the wireless terminal;
A wireless communication control method comprising: operating each of the plurality of wireless modules as the usage module according to the usage schedule determined by the base station.
A base station that performs wireless communication with wireless terminals via multiple relay devices,
The wireless terminal includes a plurality of wireless modules that perform wireless communication on mutually different channels, uses one of the plurality of wireless modules as a used module, and stops data transmission from wireless modules other than the used module. ,
The plurality of relay devices relay the wireless communication between each of the plurality of wireless modules and the base station,
The base station includes a control unit,
The control unit includes:
determining a usage schedule for each of the plurality of wireless modules such that a transmission time rate of each of the plurality of wireless modules of the wireless terminal does not exceed a predetermined upper limit;
A base station configured to notify information of the usage schedule to the wireless terminal and cause each of the plurality of wireless modules to operate as the usage module according to the usage schedule.
The base station according to claim 7,
The plurality of wireless modules include a first wireless module,
The control unit further includes:
retaining relay device status information indicating the status of each relay device connected to the base station;
In response to a connection destination inquiry from the first wireless module to each of the relay devices, selecting a first relay device as a connection destination of the first wireless module based on the relay device status information;
The base station is configured to instruct the selected first relay device to respond to the first wireless module.