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

Abstract

The present disclosure relates to a wireless communication system, a wireless communication method, and a wireless communication device. The present disclosure relates to a wireless communication system, a wireless communication method, and a wireless communication device. A wireless communication system of the present disclosure comprises: a base station with a multilink function; and a terminal with a multilink function, wherein the base station and the terminal communicate with each other 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 is configured to execute: a process of using at least one of the Lower MACs as a free link; a process of transmitting high-priority packets with high priorities from the Upper MAC to the Lower MAC of the free link; a process of transmitting non-priority packets excluding the high-priority packets from the Upper MAC to the Lower MAC other than free links; and a process of transmitting a packet possessed by the Lower MAC to the terminal via a link.

Description

[Technical Field]

[0001] The present disclosure relates to a wireless communication system, a wireless communication method, and a wireless communication device. [Background technology]

[0002] Wireless LAN base stations and terminals use CSMA / CA to access channels and transmit data.

[0003] The wireless LAN communication standard IEEE 802.11be is equipped with a multi-link function that allows multiple frequency bands to be used simultaneously. By using the multi-link function, multiple links using multiple frequency bands can be formed simultaneously between a base station and a terminal. This allows different data to be transmitted simultaneously over multiple frequency bands, improving throughput and delay characteristics.

[0004] When transmitting data, packets generated in the upper layer are first passed to the Upper MAC (Media Access Controller). The Upper MAC passes the packet to the Lower MAC, which exists for each link. When the Lower MAC acquires the right to transmit a frame, the packet that has come to the front of the queue in order of its holdings is passed to the PHY (Physical) layer, which is the physical layer, and then transmitted. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] IEEE802.11 2020 IEEE Standard for Information Technology-Telecommunications and Information Exchange between SystemsLocal and Metropolitan Area Networks-Specific Requirements [Non-patent document 2] IEEE802.11be D2.0 Draft Standard for Information technology- Telecommunications and information exchange between systems Local and metropolitan area networks- Specific requirements Summary of the Invention [Problem to be solved by the invention]

[0006] However, when performing high-volume communications, there are cases where the Lower MACs of all links used by the multi-link function already have multiple packets being transmitted. In this case, suppose a high-priority packet, which is a transmission packet for an application that requires low latency, is generated. This high-priority packet cannot be immediately handed over to the PHY for transmission, regardless of which link is used. In other words, there is a problem of queuing delays.

[0007] In order to solve the above-mentioned problems, a first object of the present disclosure is to provide a wireless communication system that can reduce queuing delay of high-priority packets.

[0008] A second object of the present disclosure is to provide a wireless communication method that can reduce queuing delay of high-priority packets.

[0009] A third object of the present disclosure is to provide a wireless communication device that can reduce queuing delay of high-priority packets. [Means for solving the problem]

[0010] A first aspect of the present disclosure is a wireless communication system comprising a base station having a multi-link function and a terminal having a multi-link function, and configured so that the base station and the terminal communicate via a plurality of links, wherein the base station preferably comprises an Upper MAC that receives packets generated in a higher layer and a Lower MAC that exists for each link, and is configured to perform the following processes: a process of using at least one of the Lower MACs as an available link; a process of causing the Upper MAC to transmit high-priority packets to the Lower MAC of the available link; a process of causing the Upper MAC to transmit non-priority packets excluding high-priority packets to the Lower MAC other than the available link; and a process of causing the Lower MAC to transmit packets held by the Lower MAC to the terminal via the link.

[0011] A second aspect of the present disclosure is a wireless communication method performed by a wireless communication system including a base station having a multi-link function and a terminal having a multi-link function, and configured so that the base station and the terminal communicate via multiple links, wherein the base station includes an Upper MAC that receives packets generated in a higher layer and a Lower MAC that exists for each link, and the wireless communication method preferably includes the steps of using at least one of the Lower MACs as an available link, transmitting high-priority packets from the Upper MAC to the Lower MAC of the available link, transmitting non-priority packets excluding the high-priority packets from the Upper MAC to the Lower MAC other than the available link, and transmitting the packets held by the Lower MAC to the terminal via the link.

[0012] A third aspect of the present disclosure is preferably a wireless communication device that includes an Upper MAC that receives packets generated in a higher layer and a Lower MAC that exists for each link, and that has the following functions: a function of using at least one of the Lower MACs as an available link; a function of transmitting high-priority packets from the Upper MAC to the Lower MAC of the available link; a function of transmitting non-priority packets other than high-priority packets from the Upper MAC to a Lower MAC other than the available link; and a function of transmitting packets held by the Lower MAC via the link. [Effects of the Invention]

[0013] According to the first, second and third aspects of the present disclosure, it is possible to reduce queuing delay of high priority packets. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 10 is a diagram illustrating an example of the configuration of a wireless communication system without a multi-link function. [Figure 2] FIG. 1 is a diagram illustrating an example of the configuration of a wireless communication system having a multi-link function. [Figure 3] 10 is a flowchart showing a multi-link setup procedure. [Figure 4] FIG. 10 is a diagram illustrating a packet categorization process. [Figure 5] 1 is a diagram illustrating a configuration example of a wireless communication system according to a first embodiment of the present disclosure. [Figure 6] 4 is a flowchart illustrating a packet processing method according to the first embodiment of the present disclosure. [Figure 7] 10 is a first flowchart showing a process of selecting an available link. [Figure 8] 10 is a second flowchart showing the process of selecting an available link. [Figure 9] 1 is a block diagram showing a device configuration of a base station according to a first embodiment of the present disclosure. [Figure 10]1 is a block diagram showing a device configuration of a terminal according to a first embodiment of the present disclosure. [Figure 11] 10 is a table illustrating an example of data held by an available link management unit according to the first embodiment of the present disclosure. [Figure 12] FIG. 10 is a diagram illustrating a configuration example of a wireless communication system according to a second embodiment of the present disclosure. [Figure 13] FIG. 11 is a diagram illustrating a configuration example of a wireless communication system according to a third embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0015] Embodiment 1 [Conventional wireless communication system] Before describing the first embodiment, a conventionally used multi-link will be described. Fig. 1 is a diagram showing an example of the configuration of a wireless communication system without a multi-link function. That is, a wireless communication system 500 transmits multiple types of packets using a single link.

[0016] The wireless communication system 500 includes a base station 2. The base station 2 transmits a high-priority packet 4 generated in an upper layer to a MAC unit 12. The MAC unit 12 includes a queue 8. The queue 8 holds received packets in an ordered manner so that the packets can be transmitted in the order in which they were received. When a 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 packet. When the wireless communication system used is Wi-Fi (registered trademark), the base station corresponds to an access point.

[0017] Because the base station 2 does not have a multi-link function, it has only one queue 8. Therefore, even if a high-priority packet 4 occurs, if the queue 8 already contains multiple packets 6, the high-priority packet 4 is ordered so that it becomes the last of the packets held by the queue 8.

[0018] The MAC unit 12 transmits the packets to the PHY 10. More specifically, the packet that has arrived at the front of 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 packets 6 held in the queue 8 up to that point have been transmitted. Note that the base station 2 does not have a multi-link function and therefore has only one PHY 10.

[0019] As described above, in the wireless communication system 500 using only one link, even if a high priority packet 4 occurs, no processing is performed to give priority to the packet.

[0020] 2 is a diagram showing an example of the configuration of a wireless communication system with a multi-link function. Here, a wireless communication system 600 that forms three links by utilizing the multi-link function will be described.

[0021] The wireless communication system 600 includes a base station 2. The base station 2 transmits a high priority packet 4 generated in an upper layer to a MAC unit 12. The MAC unit 12 includes an upper MAC 18 and lower MACs 20a, 20b, and 20c that exist for each link.

[0022] 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 one of the Lower MACs 20a, 20b, and 20c. More specifically, the high priority packet 4 is ordered so that it becomes the last of the packets held in the queue of the Lower MAC to which it was distributed. This distribution is performed based on a predetermined process. Here, it is assumed that the process is to distribute the packet to the queue with the shortest waiting time out of the queues 8a, 8b, and 8c that each of the Lower MACs 20a, 20b, and 20c has. Note that the waiting time in this case varies depending on the number or size of packets 6 held in each queue.

[0023] The MAC unit 12 transmits the packets to the PHY unit 14. This PHY unit 14 includes PHYs 10a, 10b, and 10c. More specifically, among the packets, the packets that arrive at the front of the queues 8a, 8b, and 8c are transmitted to the PHYs 10a, 10b, and 10c, respectively. That is, the high-priority packet 4 is transmitted to the terminal 16 after all the packets 6 held in the assigned queues have been transmitted.

[0024] As described above, the high-priority packet 4 is assigned to the queue that minimizes the waiting time, which increases the likelihood that the packet will be transmitted to the PHY with a shorter waiting time than in the wireless communication system 500 that uses only one link.

[0025] In this way, by using the multi-link function to simultaneously transmit different data over multiple frequency bands, throughput and delay characteristics can be improved. However, there are cases where the Lower MACs of all links used with the multi-link function already have multiple packets to transmit. In this case, the generated high-priority packet cannot be immediately passed to the PHY for transmission, regardless of which link is used. In other words, a problem occurs in which queuing delays occur. The present disclosure solves this problem.

[0026] Fig. 3 is a flowchart showing the multi-link setup procedure. The free link management units 64 and 74, which will be described later, perform the process shown in Fig. 3 to set up wireless communication via specific links. This allows the wireless communication system to establish multi-link communication.

[0027] 4 shows a process for categorizing packets. A wireless communication system transmits multiple types of packets. This shows a process for identifying the multiple types of packets by traffic in the STA unit (described later).

[0028] Packets with a MAC header added at a higher layer are input to one of queues 22, 24, 26, and 28. The destination queue is determined by the TID (Traffic Indicator) included in the MAC header. For example, when WME (Wireless Multimedia Extensions) assigns priorities, queue 22 can be identified as the VO category related to voice, queue 24 as the VI category related to video, queue 26 as the BE category related to best effort, and queue 28 as the BK category related to background.

[0029] Packets input to each queue are input to CSMA / CA units 32, 34, 36, 38, and 40. Each CSMA / CA unit accesses the channel using its own access parameters and performs CSMA / CA. The unique access parameters include, for example, Cwmax, Cwmin, AIFS, and TXOPlimit. When each CSMA / CA unit obtains the transmission right, it acquires a MAC frame from its queue and outputs it to the internal collision resolution unit 42.

[0030] The CSMA / CA units 32, 34, 36 and 38 process data that arrives at the front of the queues 22, 24, 26 and 28. The CSMA / CA unit 40 processes low-delay data.

[0031] When multiple CSMA / CA units simultaneously acquire the transmission right, the internal conflict resolution unit 42 selects and outputs the one with the highest priority.

[0032] [Wireless communication system of the present disclosure] 5 is a diagram illustrating a configuration example of a wireless communication system according to a first embodiment of the present disclosure. The wireless communication system according to the first embodiment differs from conventional systems in that it maintains a state in which there are no packets in the Lower MAC corresponding to at least one link used in the multi-link function. Hereinafter, this link will be referred to as an empty link. Hereinafter, a wireless communication system 100 that forms three links by utilizing the multi-link function will be described.

[0033] The wireless communication system 100 transmits packets in 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 an idle link and in the method of allocating packets. Note that, here, the link including the Lower MAC 20a is considered to be an idle link.

[0034] The method for selecting an available link may be to alternate available links at regular intervals. Alternatively, a link that has lost Lower MAC packets during wireless communication may be designated as a new available link. Available links may be set independently for each base station 2 and terminal 16.

[0035] 6 is a flowchart showing a packet processing method according to the first embodiment of the present disclosure. First, in step 100, the Upper MAC 18 receives a packet from an upper layer.

[0036] Next, in step 102, it is confirmed whether the priority of the received packet is high. The priority is determined by the MLD unit 59 of the base station, which will be described later. This determination may be made using the TID. For example, a method may be considered in which a packet assigned a pre-specified TID or a TID indicating a higher priority than that TID is determined to be a "high priority packet." Another method may be to pre-specify a TID for an idle link, and determine a packet that matches that TID or a packet assigned a TID indicating a higher priority than that TID as a "high priority packet." If the priority is high, proceed to step 104. If the priority is not high, proceed to step 106.

[0037] In step 104, the packet is transmitted to the available link. The packet processed in step 104 is the high-priority packet 4. That is, in the case of the wireless communication system 100, the high-priority packet 4 is transmitted to the link including the Lower MAC 20a. This allows the high-priority packet 4 to be immediately delivered to the PHY unit 14.

[0038] In addition, there may be cases where a high-priority packet already exists in the free link and the queue size of the link other than the free link is smaller than the queue size of the free link. In such cases, processing may be performed to transmit the high-priority packet 4 to the link other than the free link.

[0039] In step 106, the packet is transmitted to a link other than the idle link. The packet processed in step 106 is packet 6, which has a low priority. That is, in the case of wireless communication system 100, packet 6 is transmitted to the link including Lower MAC 20b or 20c. This maintains the idle link in a state where no packets exist.

[0040] As described above, at least one link used by the multi-link function is always kept free. When a high-priority packet is generated, it is sent to that free link. This allows the high-priority packet to be sent immediately, thereby reducing queuing delays. Another effect is that a FIFO can be achieved without changing the waiting order of packets within the MAC unit 12.

[0041] [Detailed settings for free links in this disclosure] Figure 7 is a first flowchart showing the process of selecting an available link. This shows a processing method for switching available links at regular intervals. In addition, numbers 1 to n are assigned in advance to the n links used in the multi-link function.

[0042] In step 108, the time for the n-th link starts to be counted up. That is, time t is set to t = 0. After a certain period of time has elapsed, in step 110, time t is counted up to t + 1.

[0043] In step 112, it is checked whether time t has reached a certain time T. If time T has been reached, the process proceeds to step 114. If time T has not been reached, the process returns to step 110 and the process is repeated.

[0044] In step 114, the free link is changed from the nth link to the n+1th link. Then, the process returns to step 108 and the entire process is repeated for the n+1th link. This allows free links to be rotated in order.

[0045] While Figure 7 shows an example in which free links are changed at predetermined intervals, free links may also be changed based on a time allocation determined based on information that changes over time. This time allocation may also be determined based on the proportion of high-priority packets observed on each link. The proportion of high-priority packets observed on each link refers to the proportion of high-priority packets, including those sent by other terminals, on the channel used by a certain link. In this case, the greater the proportion of high-priority packets, the shorter the time set for free links.

[0046] The time allocation may be determined based on the ratio of the total number of packets passing through each link. In this case, the larger the ratio of the total number of packets, i.e., the greater the traffic, the shorter the time set for the idle link.

[0047] The time allocation may also be determined based on the saturation level or packet error rate (PER) of the channel used by each link. In this case, the higher the packet saturation level or PER, the shorter the time allocated to the idle link.

[0048] By appropriately changing available links based on information that changes over time, it becomes easier to select a link with the shortest delay time at that time, which increases the possibility of improving the efficiency of wireless communication.

[0049] Although the embodiment has been described in which all links used in the multi-link function are candidates for selection of idle links, there may be some links that are not candidates for selection of idle links. The links that are not candidates for selection may be determined based on the channel saturation degree or PER value of the link.

[0050] As described above, by appropriately changing available links, it is possible to avoid imbalances in the load traffic assigned to each link. This makes it possible to avoid occupying specific channels, for example, when links used for the multi-link function use different channels.

[0051] 8 is a second flowchart showing the process of selecting an unused link. This flowchart shows a processing method for selecting a link from which packets of the Lower MAC address have disappeared during wireless communication as a new unused link. In this case, it is preferable to set a specific link as an unused link only when wireless communication starts.

[0052] First, as in step 116, packet transmission on a certain link is completed. Then, as in step 118, it is confirmed whether the queue of that link has become empty. That is, at that timing, it is confirmed whether the link being used by the MAC unit 12 has no packets in the queue. If it has become empty, the process proceeds to step 120, where the link is selected as an available link. If it has not become empty, this process is completed, and the available link is not changed.

[0053] If multiple links become vacant at the same time, a possible method is to select a link with a small PER or CW value, or a link with a low frame collision probability. The frame collision probability may be calculated, for example, based on information held by the base station 2. Examples of the held information include time series prediction based on past wireless frame arrival times, the number of frame arrivals, and the number of ACK reception failures.

[0054] Although the embodiment has been described in which all links used in the multi-link function are candidates for selection of idle links, there may be some links that are not candidates for selection of idle links. The links that are not candidates for selection may be determined based on the channel saturation degree or PER value of the link.

[0055] 8, it is possible that queues other than the link set at the start of wireless communication do not become empty and the free link cannot be changed. In this case, the link initially set as the free link may continue to be used as the free link.

[0056] As described above, in the process of Figure 8, a link that has become empty during wireless communication is switched to an empty link. This eliminates the need to intentionally set the link to zero packets, thereby reducing queuing delay time. Furthermore, since a link that has no packets has a short delay time, selecting this makes it easier to select a link with a short delay time at that time.

[0057] [Configuration of devices included in the wireless communication system of the present disclosure] 9 is a block diagram showing the device configuration of a base station according to the first embodiment of the present disclosure. First, data transmission from the base station 2 to other terminals will be described.

[0058] The base station 2 includes an LLC unit 58. The LLC unit 58 is a sublayer that performs logical link control. The LLC unit 58 outputs input packets to an MLD unit 59.

[0059] The MLD unit 59 is a link management unit and includes a data processing unit 60. The data processing unit 60 processes data and outputs the results to a base station measurement unit 62 and an available link management unit 64. The base station measurement unit 62 measures the elapsed time, the PER of each link, etc.

[0060] The free link management unit 64 selects a free link. The free link management unit 64 also performs the multi-link setup described with reference to Fig. 3. Furthermore, the free link management unit 64 outputs the processed packets to the STA units 66a, 66b, and 66c.

[0061] The STA units 66a, 66b, and 66c are transmitting / receiving units that receive packets input from the available link management unit 64. Then, they transmit MAC frames contained in the packets as wireless frames to other terminals. Note that data transmission and reception with other terminals is performed via antennas.

[0062] Next, a description will be given of data transmission from other terminals to the base station 2. The STA units 66a, 66b, and 66c output wireless frames received from other terminals to the available link management unit 64.

[0063] The available 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 unit 60 outputs this data to the LLC unit 58.

[0064] 10 is a block diagram showing the device configuration of a terminal according to the first embodiment of the present disclosure. First, data transmission from terminal 16 to another terminal will be described.

[0065] The terminal 16 includes an LLC unit 68. The LLC unit 68 outputs the input packet to an MLD unit 69.

[0066] The MLD unit 69 includes a data processing unit 70. The data processing unit 70 processes packets and outputs the results to a terminal measurement unit 72 and an available link management unit 74. The terminal measurement unit 72 measures the PER of each link as necessary. The measurement results are notified to a base station measurement unit included in a base station within the wireless communication system. The terminal measurement unit 72 may have the same functions as the base station measurement unit 62.

[0067] The available link management unit 74 selects a priority link. For example, it selects a link to be used for communication with the base station 2 based on information notified from the available link management unit 64 of the base station 2. Alternatively, it may have the same function as the available link management unit 64 of the base station based on information acquired by the terminal measurement unit 72. Furthermore, the available link management unit 74 outputs processed packets to the STA units 76a, 76b, and 76c.

[0068] The STA units 76a, 76b, and 76c receive packets input from the available link management unit 74. Then, they transmit MAC frames contained in the packets as wireless frames to other terminals. Note that data transmission and reception with other terminals is performed via antennas.

[0069] Next, a description will be given of data transmission from other terminals to the terminal 16. The STA units 76a, 76b, and 76c output wireless frames received from other terminals to the free link management unit 74.

[0070] The available 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 unit 70 outputs this data to the LLC unit 68.

[0071] 11 is a table illustrating an example of data stored in an available link management unit according to the first embodiment of the present disclosure. The available link management unit stores various data for each link in order to select an available link. As an example, a data set for a base station equipped with three STA units is shown here.

[0072] In this example, STA1, 2, and 3 all support the multi-link function. The link including STA1 is set as an idle link. The time count of the link including STA1 is 3, and it is expected that the idle link will be changed to another STA when the switching time count reaches 10.

[0073] The PER values ​​are also stored here. The PER values ​​of STA1, STA2, and STA3 are different. It is also possible to set idle links based on these PER values.

[0074] Embodiment 2 12 is a diagram illustrating a configuration example of a wireless communication system according to a second embodiment 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.

[0075] The wireless communication system 200 includes a base station 2. The base station 2 performs wireless communication with terminals 16a and 16b. This configuration makes it possible to reduce queuing delays when high-priority packets occur, even in wireless communication that targets a wide area, such as when multiple terminals are involved.

[0076] In this case, the base station 2 and the terminals 16a and 16b may independently select an available link, or the base station and the terminals may synchronize with each other. Figure 12 shows an example in which the available links are synchronized between the base station and the terminals.

[0077] A method for synchronizing free links between a base station and a terminal may be to notify the terminal of the selected free link from the corresponding base station. Alternatively, parameters related to changes in free links between the base station and the terminal may be set to the same value, resulting in synchronization. In this case, parameters include the link number, free link selection open time, free link setup time, etc.

[0078] When selecting an available link based on high-priority frames or PER values, a specific terminal or multiple terminals may be selected, such as the terminal with the highest transmission MCS value or the terminal with the highest load throughput value.

[0079] Embodiment 3 13 is a diagram illustrating a configuration example of a wireless communication system according to a third embodiment of the present disclosure. The wireless communication system according to the third embodiment differs from the first embodiment in that a controller that aggregates a plurality of base stations is installed.

[0080] The wireless communication system 300 includes a controller 46. The controller 46 is connected to base stations 2a and 2b. The base station 2a performs wireless communication with a terminal 16a. The base station 2b performs wireless communication with a terminal 16b. With this configuration, even in wireless communication covering a wide area such as multiple base stations, it is possible to reduce queuing delays when high-priority packets occur.

[0081] In this case, the selection of free links may be set independently by the base station and the terminal, or may be set so as to be synchronized between the base station and the terminal. Figure 13 shows an example in which free links are set so as to be synchronized between the base station and the terminal.

[0082] Furthermore, the controller 46 may be used to synchronize available links between the base stations and the terminals. For example, the controller 46 may notify the base stations 2a and 2b of available links. The base stations 2a and 2b may then notify the terminals 16a and 16b of available links, respectively. Alternatively, the controller 46 may notify both the base stations 2a and 2b and the terminals 16a and 16b of available links. [Explanation of symbols]

[0083] 2, 2a, 2b base station 4 High Priority Packets 6 packets 16, 16a, 16b terminals 46 Controller 100, 200, 300, 500, 600 wireless communication systems

Claims

1. 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 being configured to communicate with each other via a plurality of links, The base station an Upper MAC that receives packets generated in an upper layer; a Lower MAC present for each of the links; a process of using at least one of the Lower MACs as a free link; A process of transmitting a high-priority packet from the Upper MAC to the Lower MAC of the free link; a process of transmitting non-priority packets other than the high-priority packets from the upper MAC to a lower MAC other than the free link; A process of transmitting a packet held by the Lower MAC to the terminal via the link; 1. A wireless communication system configured to perform

2. The wireless communication system according to claim 1 , wherein the base station is further configured to perform a process of switching the idle link at predetermined time intervals.

3. The base station is further configured to change the predetermined time so as to eliminate imbalance in packets flowing through the plurality of links.

3. The wireless communication system according to claim 2.

4. The base station is further configured to perform a process of switching the free link to a link that has become free of packets during wireless communication.

10. The wireless communication system of claim 1.

5. the terminal includes a plurality of terminals; The base station performs wireless communication with the plurality of terminals.

10. The wireless communication system of claim 1.

6. the base station includes a plurality of base stations; a controller for controlling the plurality of base stations; The controller specifies the free link.

10. The wireless communication system of claim 1.

7. A wireless communication method performed 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 being configured to communicate via a plurality of links, The base station an Upper MAC that receives packets generated in an upper layer; a Lower MAC present for each of the links; using at least one of the Lower MACs as a free link; a step of transmitting a high-priority packet having a high priority from the Upper MAC to the Lower MAC of the idle link; transmitting non-priority packets other than the high-priority packets from the upper MAC to a lower MAC other than the idle link; causing the terminal to transmit the packet held by the Lower MAC via the link; A wireless communication method comprising:

8. an Upper MAC that receives packets generated in an upper layer; Lower MAC for each link Equipped with a function of using at least one of the Lower MACs as a free link; a function of transmitting high-priority packets from the Upper MAC to the Lower MAC of the idle link; a function of transmitting non-priority packets other than the high-priority packets from the upper MAC to a lower MAC other than the free link; a function of transmitting packets held by the Lower MAC via the link; A wireless communication device comprising:

Images