Communication device and communication method

Abstract

This communication device comprises: a communication unit that transmits frames over a plurality of links having different frequency bands; and a control unit that determines, during the execution of channel scan, not to execute channel scan over at least one link among the plurality of links.

Description

Communication apparatus and communication method

[0001] The present disclosure relates to a communication apparatus and a communication method.

[0002] IEEE 802.11be has been established as a standard for wireless LANs. MLO is one of the technologies used in IEEE 802.11be. In conventional WiFi (registered trademark), one terminal device (also referred to as a non-AP STA or simply a STA) communicates with a base station (also referred to as an AP) using one frequency band, whereas in MLO, one terminal device (also referred to as a non-AP MLD) communicates with one base station (also referred to as an AP MLD) using a plurality of frequency bands. A non-AP MLD is a device integrating STAs for a plurality of frequency bands, and an AP MLD is a device integrating APs for a plurality of frequency bands.

[0003] Note that LAN is an abbreviation for local area network. IEEE is an abbreviation for Institute of Electrical and Electronics Engineers. MLO is an abbreviation for multilink operation. STA is an abbreviation for station. AP is an abbreviation for access point. MLD is an abbreviation for multi-link device. In the following description, a non-AP MLD may be simply referred to as a STA, and an AP MLD may be simply referred to as an AP. In the context of MLO, a STA may be interpreted as a non-AP MLD, and an AP may be interpreted as an AP MLD.

[0004] Patent Document 1 proposes a technique in which a terminal scans a wireless LAN access point between intervals of streaming communication.

[0005] Japanese Unexamined Patent Application Publication No. 2007-306375

[0006] While a terminal performs channel scanning, communication is temporarily interrupted, and thus there is a problem that frame delay and / or loss may occur.

[0007] Non-limiting embodiments of the present disclosure contribute to providing a communication apparatus and a communication method that can reduce the occurrence of frame delay and / or loss caused by channel scanning.

[0008] A communication device according to one embodiment of the present disclosure includes a communication unit that transmits frames over a plurality of links with different frequency bands, and a control unit that, in the execution of a channel scan, decides not to perform a channel scan on at least one of the plurality of links.

[0009] A communication method according to one embodiment of the present disclosure involves a communication device transmitting frames over a plurality of links with different frequency bands, and deciding not to perform a channel scan on at least one of the plurality of links during the execution of a channel scan.

[0010] These comprehensive or specific embodiments may be implemented as a system, apparatus, method, integrated circuit, computer program, or recording medium, or as any combination of a system, apparatus, method, integrated circuit, computer program, and recording medium.

[0011] According to one embodiment of the present disclosure, it is possible to reduce the occurrence of frame delay and / or loss caused by channel scanning.

[0012] Further advantages and effects of one embodiment of this disclosure will be made apparent from the specification and drawings. Such advantages and / or effects are provided by several embodiments and features described in the specification and drawings, but not all of them are necessarily provided in order to obtain one or more identical features.

[0013] Figure 1 shows an example of the configuration of a wireless system according to the first embodiment. Figure 2 explains the aggregation method in MLO. Figure 3 explains the duplication method in MLO. Figure 4 explains packet reordering in MLO. Figure 5 explains the scan operation according to the second embodiment. Figure 6 shows an example of the sequence of a wireless system according to the third embodiment. Figure 7 explains the selection of links to scan according to the fourth embodiment. Figure 8 shows an example of the hardware configuration of a terminal.

[0014] The embodiments of this disclosure will be described in detail below, with reference to the drawings as appropriate. However, some unnecessarily detailed explanations may be omitted. For example, detailed explanations of already well-known matters and redundant explanations of substantially identical configurations may be omitted. This is to avoid the following explanation becoming unnecessarily verbose and to facilitate understanding for those skilled in the art.

[0015] The attached drawings and the following description are provided to enable a person skilled in the art to fully understand this disclosure, and are not intended to limit the subject matter described in the claims. In this disclosure, "and / or" may be written as " / ".

[0016] [First Embodiment] <System Configuration> Figure 1 is a diagram showing an example of the configuration of a wireless system 1 according to the first embodiment. As shown in Figure 1, the wireless system 1 includes a base station 11 and terminals 12a and 12b.

[0017] The base station 11 and terminals 12a and 12b perform wireless communication based on a wireless LAN. For example, the base station 11 and terminals 12a and 12b perform wireless communication based on MLO, one of the technologies used in IEEE 802.11be.

[0018] The number of base stations 11 and terminals 12a and 12b is not limited to the example in Figure 1. Base station 11 may also be called AP or communication device. Terminal 12 may also be called STA or communication device. In the following, if terminals 12a and 12b are not distinguished, they may simply be referred to as terminal 12.

[0019] <MLO> Figure 2 is a diagram illustrating the MLO. In Figure 2, the same components as in Figure 1 are denoted by the same reference numerals.

[0020] As shown in Figure 2, the base station 11 has an MLD 21. The terminal 12 has an MLD 22. MLD stands for multilink device.

[0021] MLD21 has three physical layers (PHY1 to PHY3), three lower MAC layers (Lower MAC1 to Lower MAC1), and one upper MAC layer (Upper MAC). Similarly, MLD22 has three physical layers (PHY1 to PHY3), three lower MAC layers (Lower MAC1 to Lower MAC3), and one upper MAC layer (Upper MAC).

[0022] MLD21 and MLD22 can establish up to three links. For example, as shown in Figure 2, PHY1 and Lower MAC1 of MLD21 and PHY1 and Lower MAC1 of MLD22 establish a 2.4GHz link. PHY2 and Lower MAC2 of MLD21 and PHY2 and Lower MAC2 of MLD22 establish a 5GHz link. PHY3 and Lower MAC3 of MLD21 and PHY3 and Lower MAC3 of MLD22 establish a 6GHz link. In other words, terminal 12 can communicate with base station 11 using three different frequency bands simultaneously.

[0023] The number of frequency bands in an MLO is not limited to three. The frequency bands used in an MLO are not limited to 2.4 GHz, 5 GHz, and 6 GHz. A link may be referred to as a channel. The lower MAC layer and upper MAC layer may be referred to as MAC layers.

[0024] For simplicity, the following explanation assumes that the MLO has three links. Furthermore, the frequency bands for these three links are assumed to be 2.4GHz, 5GHz, and 6GHz. Note that IEEE 802.11be MLO utilizes three frequency bands: 2.4GHz, 5GHz, and 6GHz.

[0025] <Communication Methods in MLO> Aggregation and duplication are considered as communication methods in MLO.

[0026] • Communication method in MLO: Aggregation method Figure 3 is a diagram illustrating the aggregation method in MLO. Figure 3 shows the MLDs 21 and 22 explained in Figure 2. In Figure 3, for the sake of simplicity, the aggregation method is explained assuming that the number of MLO links is 2.

[0027] In the aggregation scheme, different frames are transmitted across multiple links with different frequency bands. For example, as shown in Figure 3, frames 1, 3, 5, 7, and 9 are transmitted from MLD 21 to MLD 22 on link 3, and frames 2, 4, 6, 8, and 10 are transmitted from MLD 21 to MLD 22 on link 2. Frames, packets, data, and signals can be used interchangeably.

[0028] In aggregation, different frames are transmitted across multiple links with different frequency bands, thereby increasing the capacity of data communication.

[0029] • Communication method in MLO: Duplication method Figure 4 is a diagram illustrating the duplication method in MLO. Figure 4 shows the MLDs 21 and 22 explained in Figure 2. In Figure 4, for the sake of simplicity, the number of MLO links is assumed to be 2 when explaining the duplication method.

[0030] In the duplication method, the same frame is transmitted across multiple links with different frequency bands. For example, as shown in Figure 4, frames 1, 2, 3, 4, and 5 are transmitted from MLD 21 to MLD 22 on link 3, and frames 1, 2, 3, 4, and 5 are transmitted from MLD 21 to MLD 22 on link 2.

[0031] In the duplication method, the same frame is transmitted across multiple links, thereby improving the reliability of data communication.

[0032] <Handover> Handover is one of the technologies that ensures the stability of communication between a terminal and a base station. Handover ensures communication stability by switching the connection to another base station with better signal strength. For example, if a terminal moves or the signal strength deteriorates due to obstacles, it will switch the connection to another base station with better signal strength. Signal strength, signal condition, and signal quality can be used interchangeably.

[0033] During a handover, the terminal performs a channel scan to detect surrounding base stations. For example, the terminal scans all channels except the connected channel. There are two methods for channel scanning: active scanning and passive scanning.

[0034] • Active Scan: In active scan, the terminal sends a Probe Request frame and waits to receive a Probe Response frame from the base station.

[0035] Active scanning takes approximately 10-30ms per channel. For example, if a device scans all channels in the 5GHz band, it would take "20ms x 20 channels = 400ms".

[0036] Note that Probe Request frames, Probe Request signals, and Probe Requests can be used interchangeably. Probe Response frames, Probe Response signals, and Probe Responses can be used interchangeably.

[0037] • Passive Scanning: In passive scanning, the terminal waits to receive Beacon frames that the base station periodically transmits.

[0038] Beacon frames are generally transmitted at approximately 100ms intervals, meaning each channel takes more than 100ms. For example, if a device scans all channels in the 5GHz band, it will take more than 2 seconds (100ms x 20 channels).

[0039] Furthermore, Beacon frames, Beacon signals, and Beacons can be used interchangeably.

[0040] <Consideration> As explained in the <Handover> section above, a channel scan involves frequency switching. Therefore, if a terminal performs a channel scan simultaneously on all MLO links, data communication may be unavailable during the channel scan, potentially causing packet delays or losses.

[0041] Therefore, the first embodiment provides a technology to reduce packet delay / loss caused by communication interruptions due to channel scanning.

[0042] In this disclosure, the terms "link," "frequency band," and "band" may be used interchangeably. Similarly, "channel scan" and "scan" may be used interchangeably.

[0043] <Scanning Method in MLO> The terminal does not perform scans on each link of the MLO simultaneously. The terminal performs scans in a distributed manner, link by link. For example, when performing a scan, the terminal decides not to perform a scan on at least one of the multiple links. In other words, when performing a scan, the terminal performs scans on a number of links less than the number of links in the multiple links (for example, 3 links in the case of 2.4GHz, 5GHz, and 6GHz) (for example, one or two links).

[0044] The channels to be scanned may be all channels targeted by the link performing the scan, or only some of them. While the MAC layer of the terminal controls the execution of the scan, an interface can be provided to instruct the terminal's MAC layer on parameters such as the link to be scanned, the target channels, and the time spent per channel, allowing an external management entity (e.g., an application or higher layer) to control these parameters. The management entity can then instruct the timing of the scan, the channels to be scanned, and the time spent per channel for each link. This allows applications to control which links are scanned and when, and makes it easier to prevent simultaneous scanning of all links.

[0045] For example, when performing scanning on 2.4 GHz, 5 GHz, and 6 GHz links (all links), the terminal performs scanning in a distributed manner on a per-link basis. For example, the terminal determines not to perform scanning on the 5 GHz and 6 GHz links among the 2.4 GHz, 5 GHz, and 6 GHz links, and performs scanning on the 2.4 GHz link.

[0046] When the scanning of the 2.4 GHz link is completed, the terminal determines not to perform scanning on the 6 GHz and 2.4 GHz links among the 2.4 GHz, 5 GHz, and 6 GHz links, and performs scanning on the 5 GHz link.

[0047] When the scanning of the 5 GHz link is completed, the terminal determines not to perform scanning on the 2.4 GHz and 5 GHz links among the 2.4 GHz, 5 GHz, and 6 GHz links, and performs scanning on the 6 GHz link.

[0048] In the above example, the terminal can transmit packets on the 5 GHz and 6 GHz links even while performing scanning on the 2.4 GHz link. The terminal can transmit packets on the 2.4 GHz and 6 GHz links even while performing scanning on the 5 GHz link. The terminal can transmit packets on the 2.4 GHz and 5 GHz links even while performing scanning on the 6 GHz link. That is, the terminal can transmit packets without interruption even when performing scanning on a plurality of links.

[0049] Furthermore, during the scan described above, information such as the availability and parameters of links other than the one being scanned may be obtained from the detected AP. This information can be obtained by sending a Probe Request frame containing a Multi-Link element and receiving a Probe Response frame containing a Multi-Link element from the AP in the case of an active scan, or by receiving a Beacon frame containing a Multi-Link element from the AP in the case of a passive scan. For example, if information about 5GHz is obtained during a scan of a 2.4GHz link, this information may be used to adjust the scan time on the 5GHz link or to cancel the scan on the 5GHz link. Additionally, information about links other than the one being scanned may be used to determine which links to execute the MLD Association request (also called a multi-link setup request) during a handover, and to select which links to include in the multi-link setup with the handover AP and to enable / disable those links.

[0050] <Summary of the First Embodiment> When the terminal performs a scan, it decides not to perform the scan on at least one of the multiple links. This allows the terminal to avoid interruptions in packet transmission due to scanning and reduce packet delay / loss.

[0051] [Second Embodiment] When a scan is performed in MLO, packet reordering may occur. In this case, packet delay may occur, for example, due to the WiFi sorting function.

[0052] Figure 5 illustrates packet reordering in MLO. Figure 5 shows the MLO aggregation schemes for 2.4GHz and 5GHz. The rectangles between the STA (terminal) and AP (base station) in Figure 5 represent packets transmitted from the STA to the AP, with the numbers within the rectangles indicating the packet order. The rectangle to the right of the AP represents packets received by the AP, with the numbers within the rectangles indicating the packet order.

[0053] For example, the STA performs a scan on a 2.4GHz link. In this case, as shown by arrow A5a in Figure 5, the STA cannot perform data communication while scanning. Therefore, as shown by callout A5b in Figure 5, packet delays / reordering may occur. Also, in the AP, as shown by callout A5c in Figure 5, even if packet "7" is received first, output will wait until packet "6" is received, which may cause processing delays.

[0054] Therefore, the second embodiment provides a technique for reducing packet delays that may occur in MLO. The differences from the first embodiment will be described below.

[0055] <In the case of aggregation> Figure 6 is a diagram illustrating the scan operation according to the second embodiment. In Figure 6, the same components as in Figure 2 are denoted by the same reference numerals. The MLD22 may be considered as a device that integrates STAs of multiple frequency bands (three in Figure 6). Note that in the example in Figure 6, the 6GHz link (STA) is not used.

[0056] As described in the first embodiment, the MLD 22 (terminal) does not perform scans simultaneously on each link of the MLO. In the case of Figure 6, the MLD 22 does not perform scans on 5GHz while performing scans on 2.4GHz. In the example of Figure 6, as mentioned above, the 6GHz link is unused.

[0057] The upper MAC layer of MLD22 stops enqueuing the transmit buffer (lower MAC layer) of the link on which the scan will be performed before the scan is executed. For example, the upper MAC layer of MLD22 stops enqueuing the transmit buffer on a 2.4GHz link, as shown by arrow A6a in Figure 6.

[0058] In addition, MLD21 (base station) may instruct MLD22 not to send transmissions to MLD22 on the link on which the scan is to be performed. To achieve these actions, the TID-To-Link Mapping (TTLM) procedure may be used. In the procedure for requesting TTLM configuration / modification from a terminal, MLD22 sends a TID-To-Link Mapping Request frame to MLD21 to configure the mapping between Traffic Identifiers (TIDs) and each link. The traffic to be transmitted and its transmit buffer are associated with TIDs, and each link is enabled / disabled for transmission or reception for each TID. Before the scan is performed, the above actions can be achieved by disabling the link on which the scan will be performed and enabling other links for TIDs corresponding to traffic to be transmitted or received during the scan period. Alternatively, the link on which the scan will be performed may be disabled for all TIDs, regardless of whether transmission or reception is planned. Transmit buffers and queues may be used interchangeably.

[0059] The upper MAC layer of MLD22 transmits outgoing packets of traffic that were being sent on the scanning link (the link from which enqueuing has been stopped) on another link. Any link that is configured to have the TID of that traffic enabled in TTLM can be used as the other link. For example, as shown by arrow A6b in Figure 6, the upper MAC layer of MLD22 transmits packets 6, 8, and 10, which were intended to be sent on the 2.4GHz link, on the 5GHz link.

[0060] The upper MAC layer of MLD22 appropriately rearranges the transmission order of packets and outputs them to the lower MAC layer. For example, as shown in Figure 6, the upper MAC layer of MLD22 controls the order of packets during scanning so that they become packets 5, 6, ..., 10.

[0061] After scanning, the upper MAC layer of MLD22 resumes enqueuing packets to the transmit buffer. This resumption is achieved by enabling the link that was disabled during scanning in the TTLM configuration. For example, after scanning, the upper MAC layer of MLD22 alternately enqueues packets to the 2.4GHz transmit buffer and the 5GHz transmit buffer according to the aggregation scheme.

[0062] <In the case of the duplication method> The following explains the differences from the aggregation method.

[0063] As described above, in the aggregation method, the upper MAC layer of MLD22 rearranges the packets appropriately (according to the aggregation method) and outputs them to the lower MAC layer. In the duplication method, the upper MAC layer of MLD22 discards packets on the link being scanned (the link from which enqueuing has stopped). In the case of the duplication method, the same packets that were scheduled to be sent on the scanned link are sent on another link, so it is acceptable for the packets to be discarded.

[0064] <Summary of the second embodiment> In the aggregation method, the MLO terminal transmits packets to be sent on the link where scanning is performed, on the link where scanning is not performed, while scanning is being performed. This allows the MLO terminal to reduce packet delays that may occur due to the reordering of packets.

[0065] In the duplication scheme, MLO terminals discard packets sent on the link during a scan. This allows MLO terminals to reduce packet delays that may occur due to packet reordering.

[0066] [Third Embodiment] The base station cannot determine whether or not a terminal is scanning. Therefore, the base station may send packets to a terminal on a link that is being scanned.

[0067] Therefore, in the third embodiment, the terminal notifies the base station of the start of the scan before performing the scan, and notifies the base station of the end of the scan after the scan is completed.

[0068] In the scan start notification, the start time of the scan and the time required for the scan may be notified, or the scheduled end time of the scan may be notified, in which case the scan end notification may be omitted. Instead of a scan notification, a link unavailable notification may be given. In that case, the start of the link unavailable period is notified before the scan is performed, and the end of the link unavailable period or the fact that the link has become available is notified after the scan is completed. Alternatively, the duration of the link unavailable period may be notified together with the start of the link unavailable period. Instead of a link unavailable notification, the TTLM procedure described in Implementation Mobile 1 may be used to request the deactivation of the link on which the scan will be performed, with respect to the transmission from the base station to the terminal. In the description of this embodiment and its modifications, the scan start notification may be read as a link unavailable period start notification or a link deactivation notification. The scan end notification may be read as a link unavailable period end notification or a link activation notification. The following describes the parts that differ from the first embodiment.

[0069] <Sequence> Figure 7 shows an example of a sequence of a wireless system according to the third embodiment. Base station 1 shown in Figure 7 represents the base station before handover. Base station 2 represents a base station that may be the handover destination.

[0070] Before starting a scan (channel change), the terminal notifies base station 1 of the start of the scan on the link where the scan will be started (executed) (step S1).

[0071] When base station 1 receives a notification that a scan has started, it stops transmitting packets on the link from which the notification was received to the terminal that sent the scan start notification (step S2).

[0072] After notifying the start of the scan in S1, the terminal changes the channel (step S3).

[0073] The terminal sends a Probe Request to base station 2 (step S4).

[0074] The terminal determines whether or not it has received a Probe Response from base station 2 (step S5).

[0075] If the terminal receives a Probe Response from base station 2 (Yes in S5), it notifies base station 1 that the scan has ended (step S6). When base station 1 receives the notification that the scan has ended, it terminates the packet transmission stop process.

[0076] On the other hand, if the terminal does not receive a Probe Response from base station 2 (No. in S5), it changes channels (step S7) and sends a Probe Request (step S8). When base station 1 receives a notification that the scan has ended, it does not terminate the packet transmission stop process. The above process is repeated until the terminal receives a Probe Response and sends a notification that the scan has ended to base station 1.

[0077] In the sequence shown in Figure 7, when the terminal receives a Probe Response from base station 2, it notifies base station 1 that the scan is complete and terminates the scan, but is not limited to this. Even when the terminal receives a Probe Response from base station 2, it may perform a channel change (scan) on all or some of the channels.

[0078] Furthermore, although the sequence in Figure 7 shows only one base station to be scanned (only base station 2 is shown), it is not limited to this. For example, after the scan start notification (step S1), the terminal may change channels (step S3) and send a single Probe Request to multiple base stations (e.g., broadcast). The terminal may then receive Probe Responses from multiple base stations. In this way, the terminal may discover multiple base stations.

[0079] Furthermore, in the sequence shown in Figure 7, the terminal performs a channel change (step S7) when it does not receive a Probe Response (No. in S5), but it is not limited to this. For example, even if the terminal receives a Probe Response from base station 2, it may perform a channel change (step S7) and send a Probe Request to a base station other than base station 2. This allows the terminal to discover multiple base stations. Note that if the terminal continues the channel change (scan) even after receiving a Probe Response, the terminal does not send a scan completion notification to base station 1 until it has finished continuing the channel change, so that base station 1 does not send a packet to the terminal. The terminal may perform (continue) channel changes on all available channels, or it may perform channel changes on some of the available channels.

[0080] <Summary of the Third Embodiment> Before starting a scan, the terminal notifies the base station of the start of the scan on the link in which the scan will be performed, and after finishing the scan, it notifies the base station of the end of the scan on the link in which the scan was performed. After receiving notification of the start of the scan, the base station stops transmitting packets on the link in which the scan is performed until it receives notification of the end of the scan. As a result, the terminal does not have to receive packets on the link in which the scan is being performed, and packet exchange / loss can be reduced.

[0081] <Modification 1 of the Third Embodiment> In the above, the terminal notified the base station of the start and end of the scan on the link on which the scan was performed, but it is not limited to this. The terminal may also notify the base station of the start and end of the scan on a link other than the link on which the scan was performed. In this case, the terminal notifies the base station of the information of the link on which the scan was performed. The base station stops transmitting packets on the notified link.

[0082] <Modification 2 of the Third Embodiment> In the above description, an example was shown in which the base station is notified of the start of the scan in an active scan, and after the scan is completed, the base station is notified of the end of the scan. However, the invention is not limited to this. The third embodiment can also be applied to passive scans. For example, when a terminal receives a Beacon frame and starts a scan, it notifies the base station of the start of the scan on the link on which the scan is performed. After the scan is completed, the terminal notifies the base station of the end of the scan on the link on which the scan was performed.

[0083] [Fourth Embodiment] The fourth embodiment describes the method for selecting (determining) the link to perform the scan. The following describes the differences from the first embodiment.

[0084] In this disclosure, "unused link" may mean that the link is not connected to a base station or is not being used for communication. "In use link" may mean that the link is connected to a base station or is being used for communication. Unused links may occur, for example, when the link is disconnected due to terminal movement or obstacles, or immediately after the terminal is powered on. Unused and disconnected links can be used interchangeably. In use and connected links can be used interchangeably.

[0085] <When all links are unused> Figure 8 is a diagram illustrating the selection of links to scan according to the fourth embodiment. In Figure 8, the same components as in Figure 2 are denoted by the same reference numerals. The “scan” shown in Figure 8 indicates the scanning frequency of the terminal within a certain time period.

[0086] Radio waves travel further at lower frequencies. Therefore, the MLD22 (terminal) is better able to find low-frequency links among the multiple links in MLO. Accordingly, the MLD22 prioritizes scanning the lowest frequency 2.4GHz link, then the next highest priority for scanning the 5GHz link, and then the next highest priority for scanning the 6GHz link.

[0087] For example, as shown in "scan" in Figure 8, the MLD22 sets the scan frequency to be highest at 2.4 GHz, then to 5 GHz, and then to 6 GHz.

[0088] <If some links are unused> MLD22 will scan the unused links, but will not scan the links that are in use.

[0089] For example, in Figure 8, the 2.4GHz and 5GHz links are in use, and the 6GHz link is unused. In this case, the MLD22 will not perform a scan on the 2.4GHz and 5GHz links, but will perform a scan on the 6GHz link.

[0090] If there are multiple unused links, the terminal will prioritize scanning the link with the lowest frequency band among the multiple unused links, similar to the case described above under "When all links are unused."

[0091] <When all links are in use> The MLD22 selects which links to scan based on the radio wave conditions of each link in use. The scan frequency may be set higher for the selected links. For links other than the selected link, scanning will not be performed, or the scan frequency will be set lower than that of the selected link. For example, the MLD22 selects which links to scan based on the following radio wave conditions: ・RSSI (Received Signal Strength Indicator) ・Base station / terminal utilization rate and loss rate (error rate)

[0092] For example, MLD22 will determine if the RSSI of the 5GHz link is below a threshold among the 2.4GHz, 5GHz, and 6GHz links. In other words, it will determine if there is a high probability that the 5GHz link connection will be interrupted. In this case, MLD22 will perform a scan on the 5GHz link.

[0093] For example, MLD22 will determine if the utilization rate of the 5GHz link among the 2.4GHz, 5GHz, and 6GHz links is above a threshold. In other words, it will determine if there is a high probability that the 5GHz link connection will be interrupted. In this case, MLD22 will perform a scan on the 5GHz link.

[0094] For example, MLD22 will determine if the loss rate of the 5GHz link among the 2.4GHz, 5GHz, and 6GHz links exceeds a threshold. In other words, it will determine if there is a high probability that the 5GHz link connection will be interrupted. In this case, MLD22 will perform a scan on the 5GHz link.

[0095] <Summary of the fourth embodiment> When all of multiple links are unused, the terminal prioritizes scanning links with lower frequency bands. This allows the terminal to establish links earlier, potentially reducing packet delays and losses.

[0096] If some of the multiple links are unused, the terminal will perform a scan on the unused links. This allows the terminal to maintain communication on the links in use while enabling connections on the unused links, potentially reducing packet delay and loss.

[0097] If all links are in use, the terminal selects which link to scan based on the signal strength of each link. This allows the terminal to establish a link earlier and potentially reduce packet delay and loss.

[0098] <Modification 1 of the Fourth Embodiment> In the above cases of <when ​​all links are unused> and <when ​​some links are unused>, the MLD 22 prioritizes scanning in order of decreasing frequency band, but is not limited to this. The MLD 22 may prioritize selecting the links of channels found in the previous or past scan and perform the scan.

[0099] <Modification 2 of the fourth embodiment> The terminal may perform a scan when stopped. This is because scanning when stopped makes it easier to find a link (base station). The terminal can determine whether or not it is moving using position detection sensors such as an accelerometer and GPS (Global Positioning System) that it is equipped with.

[0100] <Modification 3 of the Fourth Embodiment> In the above cases of <when ​​all links are unused> and <when ​​some links are unused>, the MLD 22 prioritizes scanning in order of decreasing frequency band, but is not limited to this. The MLD 22 may prioritize scanning the 6GHz link, which has the highest frequency band, then the 5GHz link, which has the next highest frequency band, and then the 2.4GHz link, which has the next highest frequency band. For example, the MLD 22 may prioritize scanning at 6GHz, then at 5GHz, and then at 2.4GHz. In this case, links with higher communication speeds may be preferentially connected.

[0101] [Hardware Configuration] Figure 9 shows an example of the hardware configuration of terminal 12. As shown in Figure 9, terminal 12 has a control unit 31, a communication unit 32, and a storage unit 33.

[0102] The control unit 31 controls the entire terminal 12. The control unit 31 may be composed of a processor, such as a CPU (central processing unit). The functions of the MLD 22 may be implemented by the control unit 31.

[0103] The communication unit 32 communicates with the base station 11. For example, the communication unit 32 communicates with the base station 11 using aggregation and duplication methods. The communication unit 32 also communicates with the device that is the communication partner of the terminal 12. The communication unit 32 may include a transmitting unit that transmits frames and a receiving unit that receives frames.

[0104] The storage unit 33 stores the operating system (OS) program, middleware program, and application program to be executed by the control unit 31. The storage unit 33 also stores various data necessary for processing by the control unit 31. The storage unit 33 may be, for example, an SSD (solid state drive), RAM (Random Access Memory), flash memory, ROM (Read Only Memory), and / or an HDD (hard disk drive).

[0105] While embodiments have been described above with reference to the drawings, this disclosure is not limited to such examples. It will be apparent to those skilled in the art that various modifications or alterations can be conceived within the scope of the claims. Such modifications or alterations are also understood to fall within the technical scope of this disclosure. Furthermore, the components in the embodiments may be combined in any way without departing from the spirit of this disclosure.

[0106] In the embodiments described above, the notation "...part" used for each component may be replaced with other notations such as "...circuitry," "...assembly," "...device," "...unit," or "...module."

[0107] This disclosure can be implemented in software, hardware, or software in conjunction with hardware. Each functional block used in the description of the above embodiments may be implemented in part or in whole as an integrated circuit (LSI), and each process described in the above embodiments may be controlled in part or in whole by a single LSI or a combination of LSIs. An LSI may consist of individual chips, or it may consist of a single chip that includes some or all of the functional blocks. An LSI may have data inputs and outputs. Depending on the degree of integration, LSIs may be referred to as ICs, system LSIs, super LSIs, or ultra LSIs.

[0108] The integrated circuit implementation method is not limited to LSIs; it may also be implemented using dedicated circuits, general-purpose processors, or dedicated processors. Furthermore, a Field Programmable Gate Array (FPGA) that can be programmed after LSI manufacturing, or a reconfigurable processor that allows for the reconfiguration of the connections and settings of circuit cells within the LSI, may also be used. This disclosure may be implemented as digital or analog processing.

[0109] Furthermore, if advancements in semiconductor technology or related technologies lead to the emergence of integrated circuit technologies that can replace LSIs, then naturally, these technologies can be used to integrate functional blocks. The application of biotechnology, for example, is a possibility.

[0110] This disclosure is applicable to all types of devices, systems, and equipment having communication capabilities (collectively referred to as communication equipment). Communication equipment may include a radio transceiver and a processing / control circuit. The radio transceiver may include a receiver and a transmitter, or both as functions. The radio transceiver (transmitter, receiver) may include an RF (Radio Frequency) module and one or more antennas. The RF module may include an amplifier, an RF modulator / demodulator, or similar. Non-exclusive examples of communication devices include telephones (mobile phones, smartphones, etc.), tablets, personal computers (PCs) (laptops, desktops, notebooks, etc.), cameras (digital still / video cameras, etc.), digital players (digital audio / video players, etc.), wearable devices (wearable cameras, smartwatches, tracking devices, etc.), game consoles, digital book readers, telehealth / telemedicine devices, vehicles or mobile transport with communication capabilities (cars, airplanes, ships, etc.), and combinations of the above-mentioned devices.

[0111] Communication devices are not limited to portable or movable devices, but also include all kinds of non-portable or fixed devices, devices, and systems, such as smart home devices (appliances, lighting fixtures, smart meters or measuring instruments, control panels, etc.), vending machines, and any other "things" that may exist on an IoT (Internet of Things) network.

[0112] Communication includes data communication via cellular systems, wireless LAN systems, and communication satellite systems, as well as data communication using combinations of these.

[0113] Furthermore, the communication device also includes devices such as controllers and sensors that are connected to or linked to a communication device that performs the communication functions described in this disclosure. For example, this includes controllers and sensors that generate control signals and data signals used by the communication device that performs the communication functions of the communication device.

[0114] Furthermore, communication equipment includes infrastructure facilities such as base stations, access points, and any other devices, devices, and systems that communicate with or control the aforementioned non-limited types of equipment.

[0115] All disclosures in the specification, drawings, and abstract contained in the Japanese application No. 2025-048669, filed on March 24, 2025, are incorporated herein by reference.

[0116] This disclosure is useful for wireless LANs that utilize MLO.

[0117] 1 Wireless system 11 Base stations 12, 12a, 12b Terminals 21, 22 MLD 31 Control unit 32 Communication unit 33 Storage unit

Claims

1. A communication device comprising: a communication unit that transmits frames on multiple links with different frequency bands; and a control unit that, in the execution of a channel scan, decides not to perform a channel scan on at least one of the multiple links.

2. The communication device according to claim 1, wherein, in a first communication method for transmitting different frames on multiple links with different frequency bands, the communication unit transmits frames to be transmitted on the link where the channel scan is performed on the link where the channel scan is not performed while the channel scan is being performed.

3. The communication device according to claim 1, wherein the communication unit, in a second communication method in which the same frame is transmitted on multiple links with different frequency bands, discards frames to be transmitted on the link in which a channel scan is performed while the channel scan is being performed.

4. The communication device according to claim 1, wherein the control unit notifies the base station of the start of a channel scan before starting a channel scan, and notifies the base station of the end of a channel scan after finishing a channel scan.

5. The communication device according to claim 1, wherein, if all of the plurality of links are unused, the control unit gives a higher priority to performing a channel scan on links with lower frequency bands.

6. The communication device according to claim 1, wherein the control unit performs a channel scan on unused links when some of the plurality of links are unused.

7. The communication device according to claim 1, wherein the control unit selects a link to perform a channel scan on according to the radio wave conditions of each link when all of the plurality of links are in use.

8. A communication method comprising a communication device that transmits frames on multiple links with different frequency bands, and in performing a channel scan, decides not to perform a channel scan on at least one of the multiple links.

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