WO2024013801A1

WO2024013801A1 - Wireless communication system, wireless communication method, and wireless communication device

Info

Publication number: WO2024013801A1
Application number: PCT/JP2022/027259
Authority: WO
Inventors: 花絵大谷; 裕介淺井; ヒランタアベセカラ; 朗岸田; 純一岩谷; 信也大槻; 陸大宮; 泰司鷹取
Original assignee: 日本電信電話株式会社
Priority date: 2022-07-11
Filing date: 2022-07-11
Publication date: 2024-01-18

Abstract

The present disclosure relates to a wireless communication system, a wireless communication method, and a wireless communication device. A wireless communication device according to the present disclosure comprises a base station having a multilink function and a terminal having a multilink function, and is configured such that the base station and the terminal communicate via a plurality of links. The base station comprises an Upper MAC that receives a packet generated in a higher-level layer, and a Lower MAC present in each link, and is configured so as to execute: processing for using at least one out of the links as a priority link including a Lower MAC for which a maximum queuing size is set; processing for, when the priority of the packet is low and the priority link reaches the maximum queuing size, using links other than the priority link as candidates for a packet assignment destination link; processing for determining the packet assignment destination link by predetermined processing; processing for transmitting the packet from the Upper MAC to the Lower MAC of the assignment destination link; and processing for transmitting the packet which the Lower MAC has to the terminal via the link.

Description

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

The present disclosure relates to a wireless communication system, a wireless communication method, and a wireless communication device.

Wireless LAN base stations and terminals use CSMA/CA to access channels and transmit data.

IEEE 802.11be, a wireless LAN communication standard, is equipped with a multi-link function that allows multiple frequency bands to be used together. By using the multilink function, multiple links using multiple frequency bands can be simultaneously formed between a base station and a terminal. This improves throughput and delay characteristics by simultaneously transmitting different data in multiple frequency bands.

When transmitting data, packets generated in the upper layer are first passed to the Upper MAC (Media Access Controller). The Upper MAC passes packets to the Lower MAC that exists for each link. When the Lower MAC acquires the right to transmit a frame, the packet that comes to the forefront in the order of held packets is passed to the physical layer (PHY), and then transmitted.

However, when performing large-capacity communication, the Lower MACs of all links used in the multilink function may already have multiple transmission packets. In this case, it is assumed that a high-priority packet is generated, which is a transmission packet of an application that requires low delay. This high priority packet cannot be immediately passed to the PHY and transmitted using any link. That is, there was a problem in that queuing delays occurred.

In order to solve the above-mentioned problems, the first object of the present disclosure is to provide a wireless communication system that can shorten the queuing delay of high-priority packets.

A second objective of the present disclosure is to provide a wireless communication method that can shorten the queuing delay of high-priority packets.

A third objective of the present disclosure is to provide a wireless communication device that can shorten the queuing delay of high-priority packets.

A first aspect of the present disclosure is a wireless communication system that includes a base station with a multilink function and a terminal with the multilink function, and is configured such that the base station and the terminal communicate via multiple links. The base station includes an Upper MAC that receives packets generated in the upper layer, and a Lower MAC that exists for each link, and connects at least one of the links to the Lower MAC that has a maximum queuing size set. processing to use as a priority link including a priority link, processing to use a link other than the priority link as a candidate for a link to which the packet is to be distributed when the priority of the packet is low and the priority link has reached the maximum queuing size, and a predetermined processing. Executes processing to determine the link to which the packet is to be distributed, processing to transmit the packet from the Upper MAC to the Lower MAC of the distribution destination link, and processing to transmit the packet possessed by the Lower MAC to the terminal via the link. Preferably, the wireless communication system is configured to.

A second aspect of the present disclosure provides a wireless communication system that includes a base station with a multilink function and a terminal with a multilink function, and is configured such that the base station and the terminal communicate via a plurality of links. A wireless communication method in which a base station includes an Upper MAC that receives packets generated in an upper layer and a Lower MAC that exists for each link, and sets at least one of the Lower MACs to a maximum queuing size. a step of using the link as a priority link including the set Lower MAC, and a step of using a link other than the priority link as a candidate link to which the packet is to be distributed if the priority of the packet is low and the priority link has reached the maximum queuing size. , a step of determining the link to which the packet is to be distributed by a predetermined process, a step of transmitting the packet from the Upper MAC to the Lower MAC of the destination link, and transmitting the packet possessed by the Lower MAC to the terminal via the link. Preferably, the wireless communication method includes the step of:

A third aspect of the present disclosure includes an Upper MAC that receives packets generated in an upper layer and a Lower MAC that exists for each link, and at least one of the Lower MACs has a maximum queuing size set. A function to use as a priority link including Lower MAC, a function to select a link other than the priority link as a candidate link for packet distribution when the priority of the packet is low and the priority link has reached the maximum queuing size, and predetermined processing. , a wireless communication system with a function of determining a link to which a packet is to be distributed, a function of transmitting the packet from the Upper MAC to the Lower MAC of the destination link, and a function of transmitting the packet possessed by the Lower MAC via the link. Preferably, it is a communication device.

According to the first, second, and third aspects of the present disclosure, the queuing delay of high-priority packets can be reduced.

1 is a diagram illustrating a configuration example of a wireless communication system without a multilink function. 1 is a diagram illustrating a configuration example of a wireless communication system when there is a multilink function. 3 is a flowchart showing a multi-link setup procedure. FIG. 3 is a diagram illustrating packet categorization processing. 1 is a diagram illustrating a configuration example of a wireless communication system according to Embodiment 1 of the present disclosure. 3 is a flowchart illustrating a packet processing method according to Embodiment 1 of the present disclosure. 1 is a block diagram showing the device configuration of a base station according to Embodiment 1 of the present disclosure. FIG. 1 is a block diagram showing the device configuration of a terminal according to Embodiment 1 of the present disclosure. FIG. 3 is a table showing an example of data held by a priority link management unit according to Embodiment 1 of the present disclosure. FIG. 2 is a diagram illustrating a configuration example of a wireless communication system according to Embodiment 2 of the present disclosure. FIG. 3 is a diagram illustrating a configuration example of a wireless communication system according to Embodiment 3 of the present disclosure. FIG. 7 is a diagram illustrating a configuration example of a wireless communication system according to Embodiment 4 of the present disclosure.

Embodiment 1
[Conventional wireless communication system]
Prior to describing the first embodiment, a conventionally used multilink will be described. FIG. 1 is a diagram showing an example of the configuration of a wireless communication system without a multilink function. That is, the wireless communication system 500 transmits multiple types of packets using one link.

The wireless communication system 500 includes a base station 2. The base station 2 transmits the high priority packet 4 generated in the upper layer to the MAC unit 12. The MAC unit 12 includes a queue 8 . The queue 8 holds received packets in an ordered manner so that they can be transmitted in the order in which they are received. When the frame transmission right is acquired, the order of the packets held in the queue 8 is checked, and the packets are transmitted in order starting from the front row. Note that when the applied wireless communication system is Wi-Fi (registered trademark), the base station corresponds to an access point.

The base station 2 has only one queue 8 because it does not have a multilink function. Therefore, even if a high-priority packet 4 occurs, if the queue 8 already has multiple packets 6, the high-priority packet 4 is ordered so that it becomes the last packet held in the queue 8. I do.

The MAC unit 12 transmits the packet to the PHY 10. More specifically, among the packets, the one that comes to the forefront in the order of the packets held by the queue 8 is transmitted to the PHY 10. That is, the high priority packet 4 transmitted to the PHY 10 is transmitted to the terminal 16 after all the packets 6 held in the queue 8 up to that point have been transmitted. Note that since the base station 2 does not have a multilink function, it also includes only one PHY 10.

As described above, in the wireless communication system 500 that uses only one link, even when the high priority packet 4 occurs, no process is performed to give priority to it.

FIG. 2 is a diagram showing a configuration example of a wireless communication system when there is a multilink function. Here, a wireless communication system 600 that forms three links by using a multilink function will be described.

The wireless communication system 600 includes a base station 2. The base station 2 transmits the high priority packet 4 generated in the upper layer to the MAC unit 12. The MAC unit 12 includes an Upper MAC 18 and

Lower MACs

20a, 20b, and 20c that exist for each link.

The MAC unit 12 first receives the high priority packet 4 at the Upper MAC 18. The Upper MAC 18 distributes the high priority packet 4 to any one of the

Lower MACs

20a, 20b, and 20c. More specifically, the high-priority packet 4 is ordered so that it becomes the last packet held in the queue provided by the assigned Lower MAC. This distribution is performed based on predetermined processing. Here, it is assumed that among the

queues

8a, 8b, and 8c provided in each of the

Lower MACs

20a, 20b, and 20c, processing is performed to allocate to the queue with the shortest waiting time. Note that the waiting time in this case changes depending on the number or size of packets 6 that each queue has.

The MAC unit 12 transmits the packet to the PHY unit 14. This PHY unit 14 includes

PHYs

10a, 10b, and 10c. More specifically, among the packets, those that come to the forefront in the order of the packets held by each of the

queues

8a, 8b, and 8c are transmitted to each of the

PHYs

10a, 10b, and 10c. That is, the high-priority packet 4 is transmitted to the terminal 16 after all the packets 6 held in the sorted queue have been transmitted.

As mentioned above, the high priority packet 4 is distributed to the queue with the shortest waiting time. Therefore, compared to the wireless communication system 500 that uses only one link, it is possible to increase the possibility that transmission to the PHY will be performed with a shorter waiting time.

In this way, throughput and delay characteristics can be improved by transmitting different data simultaneously in multiple frequency bands using the multilink function. However, the Lower MACs of all links used in the multilink function may already have multiple transmission packets. The high-priority packet generated in this case cannot be immediately delivered to the PHY and transmitted no matter which link is used. That is, a problem arises in which a queuing delay occurs. The present disclosure solves this problem.

FIG. 3 is a flowchart showing the multilink setup procedure. Priority

link management units

64 and 74, which will be described later, perform the process shown in FIG. 3 to configure settings so that wireless communication can be performed via specific links. This allows the wireless communication system to establish multi-link communication.

FIG. 4 is a diagram showing packet categorization processing. Wireless communication systems transmit multiple types of packets. Here, a process is shown in which the plurality of types of packets are identified for each traffic in the STA unit, which will be described later.

A packet to which a MAC header is added in the upper layer is input to one of the

queues

22, 24, 26, and 28. The input destination queue is determined by the TID (Traffic Indicator) included in the MAC header. For example, when WME (Wireless Multimedia Extensions) prioritizes, queue 22 is a VO category related to audio, queue 24 is a VI category related to video, queue 26 is a BE category related to best effort, and queue 28 is a BK category related to background. can be identified.

The packets input to each queue are input to the CSMA/

CA sections

32, 34, 36, 38, and 40. Each CSMA/CA unit uses unique access parameters to access the channel and perform CSMA/CA. The unique access parameters are, for example, Cwmax, Cwmin, AIFS, and TXOPlimit. When each CSMA/CA unit obtains the transmission right, it acquires a MAC frame from each queue and outputs it to the internal conflict resolution unit 42.

Note that the CSMA/

CA units

32, 34, 36, and 38 process those that have arrived at the front of the

queues

22, 24, 26, and 28. The CSMA/CA unit 40 processes low delay data.

When multiple CSMA/CA units acquire transmission rights at the same time, the internal conflict resolution unit 42 selects and outputs the one with the highest priority.

[Wireless communication system of the present disclosure]
FIG. 5 is a diagram illustrating a configuration example of a wireless communication system according to Embodiment 1 of the present disclosure. The wireless communication system according to the first embodiment differs from the conventional example in that the maximum queuing size is set in the Lower MAC of at least one link used in the multilink function. Hereinafter, this at least one link will be referred to as a priority link. Here, a wireless communication system 100 that forms three links by using a multilink function will be described.

The wireless communication system 100 transmits packets using the same procedure as the wireless communication system 600. However, the wireless communication system 100 differs from the wireless communication system 600 in that it has a priority link and in the method of allocating packets. Note that here, the link including the Lower MAC 20a is set as the priority link.

This section describes how to sort packets. FIG. 6 is a flowchart illustrating a packet processing method according to Embodiment 1 of the present disclosure. First, in step 100, the Upper MAC 18 receives a packet from an upper layer.

Next, in step 102, it is checked whether the received packet has a high priority. The determination of priority is performed by the MLD unit 59 of the base station, which will be described later. TID may be used for this determination. For example, a method may be considered in which a packet to which a prespecified TID or a TID indicating a higher priority than the TID is assigned is determined to be a "high priority packet." If the priority is high, proceed to step 104. If the priority is not high, proceed to step 106.

In step 104, a transmission link is selected for all links used in the wireless communication system. In the case of the wireless communication system 100, a link to be allocated is selected from all links including each of the

Lower MACs

20a, 20b, and 20c. Note that this selection is performed based on predetermined processing.

In step 106, it is checked whether the queue size of the priority link has reached its upper limit. In the case of the wireless communication system 100, it is checked whether the link including the Lower MAC 20a has reached the maximum queuing size. If the maximum queuing size has not been reached, proceed to step 104. If the maximum queuing size has been reached, proceed to step 108.

In step 108, transmission links are selected for links other than priority links. In the case of the wireless communication system 100, links including the Lower MAC 20a, which is a priority link, are excluded. In other words, a link to be allocated is selected from among the links including the

Lower MACs

20b and 20c. Note that this selection is performed based on predetermined processing.

Here, it is assumed that the predetermined process for selecting a link to which to distribute is a method of distributing to a Lower MAC that has a queue with the shortest waiting time. The priority link has a maximum queuing size set. Therefore, especially when performing large-capacity communication, there is a high possibility that the waiting time will be lower than other links. As a result, the high priority packet 4 is more likely to be distributed to the priority link.

When the high-priority packet 4 is distributed to the priority link, the maximum queuing size is set for the priority link, so the queuing delay is shortened to a certain time or less. If the high-priority packet 4 is not distributed to a priority link, this means that the destination link has a shorter waiting time than the priority link, so the queuing delay is still reduced to a certain time or less. That is, in either case, the queuing delay can be reduced to a certain time or less.

As described above, in the first embodiment, the maximum queuing size is set for a specific link, and then the process shown in the flowchart of FIG. 6 is performed. That is, generated high-priority packets can be delivered to the PHY within a certain queuing time. This makes it possible to shorten the queuing delay no matter when a high-priority packet occurs.

[Details of preferred link settings for this disclosure]
The priority link may be determined based on transmission delay time or PER (Packet Error Rate). For example, the transmission delay time and PER of each link are acquired in advance within the wireless terminal or within a controller attached to the wireless terminal. Then, a method may be considered in which the link with the smallest transmission delay time or PER is selected.

Additionally, the maximum queuing size may be set to a predetermined maximum number of packets that can be accommodated in the link. Alternatively, the queuing time may be set so as not to exceed a certain queuing time based on statistics regarding communication between the base station and the terminal. Examples of statistics related to communication between a base station and a terminal include statistics related to frame transmission status of the base station or communication with other terminals. A specific example of the frame transmission status of the base station is the value obtained by dividing the frame size transmitted within the own terminal by the MCS value. Specific examples of statistics related to communication with other terminals include the expected value of delay time calculated from the PER of the link or the channel usage rate, or the actually measured transmission throughput and delay time.

Note that the above-mentioned priority link and maximum queuing size may be updated at regular intervals. For example, you can first select the link with the lowest channel usage rate at regular intervals, or you can calculate the average queuing time of all links at regular intervals and multiply this by a constant to determine the maximum queuing size. etc. are possible.

By changing the priority link at regular intervals, it is possible to avoid uneven load traffic allocated to each link. Furthermore, it is possible to expect an increase in the probability that a high-priority packet can be assigned to a link with a small delay time.

[Configuration of device included in wireless communication system of the present disclosure]
FIG. 7 is a block diagram showing the device configuration of a base station according to Embodiment 1 of the present disclosure. First, data transmission from the base station 2 to another terminal will be explained.

The base station 2 includes an LLC section 58. The LLC unit 58 is a sublayer that performs logical link control. LLC section 58 outputs the input packet to MLD section 59.

The MLD section 59 is a link management section and includes a data processing section 60. The data processing unit 60 processes data and outputs the results to the base station measurement unit 62 and priority link management unit 64. The base station measurement unit 62 measures elapsed time, PER of each link, packet transmission delay time, and the like.

The priority link management unit 64 selects priority links, manages queuing size, and selects output destination links. Further, the priority link management unit 64 performs the multi-link setup described in FIG. 3. The priority link management section 64 outputs the processed packets to the

STA sections

66a, 66b, and 66c.

The

STA units

66a, 66b, and 66c are transmitting/receiving units, and receive packets input from the priority link management unit 64. Then, the MAC frame included in the packet is transmitted to another terminal as a wireless frame. Note that data transmission and reception with other terminals is performed via an antenna.

Next, data transmission from another terminal to the base station 2 will be explained. The

STA sections

66a, 66b, and 66c output radio frames received from other terminals to the priority link management section 64.

The priority link management unit 64 processes the header and the like from the MAC frame included in the input wireless frame, and outputs the obtained data to the data processing unit 60. The data processing section 60 outputs this data to the LLC section 58.

FIG. 8 is a block diagram showing the device configuration of a terminal according to Embodiment 1 of the present disclosure. First, data transmission from the terminal 16 to another terminal will be explained.

The terminal 16 includes an LLC section 68. LLC section 68 outputs the input packet to MLD section 69 .

The MLD section 69 includes a data processing section 70. The data processing unit 70 processes the packet and outputs the results to the terminal measurement unit 72 and the priority link management unit 74. The terminal measurement unit 72 measures the PER etc. of each link as necessary. This measurement result is notified to a base station measurement unit included in a base station within the wireless communication system. Note that the terminal measuring section 72 may have the same functions as the base station measuring section 62.

The priority link management unit 74 selects priority links, manages queuing size, and selects output destination links. For example, based on information notified from the priority link management unit 64 of the base station 2, a link to be used in communication with the base station 2 is selected. Alternatively, it may have the same function as the priority link management section 64 of the base station based on the information acquired by the terminal measurement section 72. Furthermore, the priority link management unit 74 outputs the processed packets to the

STA units

76a, 76b, and 76c.

The

STA sections

76a, 76b, and 76c receive packets input from the priority link management section 74. Then, the MAC frame included in the packet is transmitted to another terminal as a wireless frame. Note that data transmission and reception with other terminals is performed via an antenna.

Next, data transmission from another terminal to the terminal 16 will be explained. The

STA sections

76a, 76b, and 76c output radio frames received from other terminals to the priority link management section 74.

The priority link management unit 74 processes the header and the like from the MAC frame included in the input wireless frame, and outputs the obtained data to the data processing unit 70. The data processing section 70 outputs this data to the LLC section 68.

FIG. 9 is a table showing an example of data held by the priority link management unit according to Embodiment 1 of the present disclosure. The priority link management section holds various data for each link in order to select priority links. Here, as an example, a data group in a base station including three STA sections is shown.

In this example, STAs 1, 2, and 3 all support the multilink function. However, only STAs 1 and 2 are used for multilink transmission. Further, since the maximum number of packets is set only for STA2, it can be seen that the link including STA2 is a priority link.

The current number of packets in STA2 is 5, which has reached the maximum number of packets. The current number of packets of STA1 is 8, which is greater than that of STA2. Therefore, when using the processing method shown in FIG. 6, if the next generated packet is a high priority packet, it is considered that it will be distributed to STA2.

The value of PER is also held here. It can be seen that the PERs of STAs 1 and 2 are different values. It is also possible to set a priority link based on this PER value.

Embodiment 2
FIG. 10 is a diagram illustrating a configuration example of a wireless communication system according to Embodiment 2 of the present disclosure. The wireless communication system according to the second embodiment differs from the first embodiment in that a plurality of terminals are targets of wireless communication with one base station.

The wireless communication system 200 includes a base station 2. Base station 2 performs wireless communication with

terminals

16a, 16b, and 16c. With this configuration, it is possible to shorten the queuing delay when a high-priority packet occurs even in wireless communication that targets a wide range and targets multiple terminals.

Consider the case where the MCS value, the proportion of high priority frames, or the PER value is referred to when selecting a priority link or determining the queuing size. In this case, the focus may be on one specific terminal, or on each of a plurality of terminals.

Embodiment 3
FIG. 11 is a diagram illustrating a configuration example of a wireless communication system according to Embodiment 3 of the present disclosure. The wireless communication system according to the third embodiment differs from the first embodiment in that a controller that bundles a plurality of base stations is installed.

The wireless communication system 300 includes a controller 46. Controller 46 is connected to

base stations

2a and 2b. The base station 2a performs wireless communication with the terminal 16a. The base station 2b performs wireless communication with the terminal 16b. With this configuration, it is possible to shorten the queuing delay when a high-priority packet occurs even in wireless communication that targets a wide area and includes multiple base stations.

Note that the controller 46 may estimate the transmission delay of high-priority frames between channels, or specify the priority link or maximum queuing size of each base station. At this time, it may be performed based on the congestion status or PER of the channels used by the

base stations

2a and 2b.

Embodiment 4
FIG. 12 is a diagram illustrating a configuration example of a wireless communication system according to Embodiment 4 of the present disclosure. The wireless communication system according to the fourth embodiment differs from the first embodiment in that priority links are synchronized between a specific base station and a specific terminal.

The wireless communication system 400 includes a base station 2 and a terminal 16. The base station 2 and the terminal 16 are set so that their priority links are synchronized. That is, the wireless communication system 400 shows the configuration of the wireless communication system 100 when priority links are synchronized.

An example of a method for synchronizing priority links is a method in which the base station 2 notifies the terminal 16 of the selected priority link and maximum queuing size. Alternatively, a method may be exemplified in which each of the base station 2 and the terminal 16 changes the link number to be a priority link every time a set time elapses. In this case, it is necessary to match conditions such as link number, priority link selection start time, and priority link setting period between the base station 2 and the terminal 16 in advance.

Further, in the case of a wireless communication system configured to use a controller that bundles a plurality of base stations or Upper MACs, an example of a method is to synchronize priority links using the controller. In this case, a method may be considered in which information on priority links and maximum queuing size is notified from the controller to each base station, and from each base station to each terminal. Alternatively, a method may be considered in which the controller notifies both each base station and each terminal of information on the priority link and maximum queuing size.

2, 2a, 2b base station 6

packet

8, 8a, 8b, 8c

queue

16, 16a, 16b, 16c terminal 46

controller

100, 200, 300, 400, 500, 600 wireless communication system

Claims

A wireless communication system comprising a base station having a multi-link function and a terminal having a multi-link function, the base station and the terminal communicating through a plurality of links,
The base station is
an Upper MAC that receives packets generated in the upper layer;
Lower MAC that exists for each link,
a process of using at least one of the links as a priority link including the Lower MAC to which a maximum queuing size is set;
If the priority of the packet is low and the priority link has reached a maximum queuing size, a process of setting a link other than the priority link as a candidate link to which the packet is to be distributed;
A process of determining a link to which the packet is to be distributed by a predetermined process;
a process of transmitting the packet from the Upper MAC to the Lower MAC of the distribution destination link;
a process of transmitting a packet possessed by the Lower MAC to the terminal via the link;
A wireless communications system configured to perform.
The predetermined process is
The wireless communication system according to claim 1, wherein the process selects a link with the shortest waiting time from the candidates for the allocation destination link.
The wireless communication system according to claim 1, wherein the priority link is determined based on transmission delay time or PER.
The maximum queuing size is
determined based on a predetermined maximum number of packets that can be accommodated in the priority link or statistics regarding communication between the base station and the terminal;
The wireless communication system according to claim 1.
The wireless communication system according to claim 1, wherein the priority link and the maximum queuing size are updated at regular intervals.
the terminal includes a plurality of terminals,
The wireless communication system according to claim 1, wherein the base station performs wireless communication with the plurality of terminals.
the base station includes a plurality of base stations,
comprising a controller that controls the plurality of base stations,
The wireless communication system of claim 1, wherein the controller specifies the priority link or the maximum queuing size.
The wireless communication system according to claim 1, wherein a priority link included in the terminal is synchronized with the base station.
A wireless communication method carried out by a wireless communication system comprising a base station having a multi-link function and a terminal having a multi-link function, the base station and the terminal communicating through a plurality of links, ,
The base station is
an Upper MAC that receives packets generated in the upper layer;
a Lower MAC that exists for each link;
using at least one of the Lower MACs as a priority link including the Lower MAC set with a maximum queuing size;
If the priority of the packet is low and the priority link has reached a maximum queuing size, selecting a link other than the priority link as a candidate link to which the packet is to be distributed;
determining a link to which the packet is to be distributed by a predetermined process;
transmitting the packet from the Upper MAC to the Lower MAC of the distribution destination link;
A wireless communication method comprising: transmitting a packet possessed by the Lower MAC to the terminal via the link.
an Upper MAC that receives packets generated in the upper layer;
Equipped with a Lower MAC that exists for each link,
a function of using at least one of the Lower MACs as a priority link including the Lower MAC to which a maximum queuing size is set;
If the priority of the packet is low and the priority link has reached a maximum queuing size, a function that selects a link other than the priority link as a candidate link to which the packet is to be distributed;
a function that determines a link to which the packet is to be distributed through predetermined processing;
a function of transmitting the packet from the Upper MAC to the Lower MAC of the distribution destination link;
A wireless communication device comprising: a function of transmitting a packet possessed by the Lower MAC via the link.