Multicast service transmission method and device suitable for multi-link

Abstract

The application is suitable for multicast service transmission method and device of multi-link. Multicast service indication information sent by a first AP of an AP MLD is used to indicate whether an AP of the AP MLD has multicast service. The AP is the first AP or other AP of the AP MLD. A first STA of a STA MLD can know whether the first AP or the other AP has multicast service, which improves the flexibility of multicast service notification of the AP. The multicast service indication information is used to indicate whether each AP of a plurality of or all APs of the AP MLD has multicast service. The first STA can know whether the plurality of APs has multicast service, which avoids each STA of the STA MLD from listening to whether each AP has multicast service, thereby saving the power consumption of the STA MLD. The application can be applied to a wireless local area network system supporting IEEE 802.11ax next generation WiFi EHT protocol, such as 802.11be and other 802.11 series protocols.

Description

Technical Field

[0001] This application relates to the field of communication technology, and in particular to a method and apparatus for multicast service transmission applicable to multiple links. Background Technology

[0002] To significantly improve the service transmission rate of wireless local area network (WLAN) systems, the IEEE (Institute of Electrical and Electronics Engineers) 802.11ax standard, building upon existing Orthogonal Frequency Division Multiplexing (OFDM) technology, further adopts Orthogonal Frequency Division Multiple Access (OFDMA) technology. OFDMA technology supports multiple nodes simultaneously transmitting and receiving data, thereby achieving multi-site diversity gain. In addition, the U.S. Federal Communications Commission (FCC) has opened a new free frequency band of 5925-7125MHz, hereinafter referred to as the 6GHz band. Therefore, the operating range of 802.11ax devices has been extended from 2.4GHz and 5GHz to 2.4GHz, 5GHz, and 6GHz.

[0003] IEEE 802.11ax next-generation WiFi protocol - Extremely High Throughput (EHT) devices, due to backward compatibility, will also support the operating spectrum of 802.11ax devices, namely the 2.4GHz, 5GHz, and 6GHz bands. IEEE 802.11ax next-generation WiFi protocol - EHT devices utilize the newly opened and free 6GHz band, allocating channels based on this band, and can support bandwidth exceeding the maximum bandwidth supported by 160MHz in 5GHz, for example, 320MHz.

[0004] In addition to ultra-high bandwidth, next-generation WiFi-EHT devices based on IEEE 802.11ax can also improve peak throughput by increasing the number of streams, such as up to 16 streams, and by cooperating across multiple frequency bands (2.4GHz, 5GHz, and 6GHz). On the same frequency band, peak throughput can also be improved and service transmission latency reduced by cooperating across multiple channels. This article refers to multiple frequency bands or multiple channels collectively as multi-link.

[0005] IEEE 802.11ax next-generation WiFi-EHT devices use multi-link cooperation technology to aggregate discontinuous links to create ultra-large bandwidth. Besides aggregating greater bandwidth, multi-link cooperation also allows for the simultaneous transmission of data packets carrying the same service to the same site. This significantly improves transmission speed. However, for downlink multicast service transmission, each site in the multi-link device needs to periodically be active to monitor whether each access point in the access point multi-link device is sending downlink multicast services, resulting in higher energy consumption. Summary of the Invention

[0006] This application provides a method and apparatus for multicast service transmission applicable to multiple links, which helps to save power consumption of multi-link equipment at sites.

[0007] In a first aspect, this application provides a method for transmitting multicast services applicable to multiple links. In this method, the first access point (AP) of the access point multilink device (AP MLD) generates multicast service indication information, which is used to indicate whether one or more APs of the AP MLD have multicast services; the first AP sends the multicast service indication information.

[0008] In one implementation, multicast service indication information is used to indicate whether an AP in the AP MLD has multicast service, which can be either the first AP or other APs in the AP MLD. This implementation improves the flexibility of multicast service notification compared to a method where sites managed by the first AP can only know whether the first AP has multicast service.

[0009] In another implementation, the multicast service indication information is used to indicate whether each AP in the AP MLD has multicast service. Compared with the method where the station managed by the first AP can only know whether the first AP has multicast service, this implementation avoids the need for each STA in the STA MLD to periodically listen for the corresponding AP to have multicast service. That is, in this implementation, one station of the STA MLD can know whether multiple APs have multicast service, thereby saving the power consumption of the STA MLD.

[0010] In another implementation, the multicast service indication information is used to indicate whether each AP in the AP MLD has multicast service. Compared with the method where the station managed by the first AP can only know whether the first AP has multicast service, this implementation avoids the need for each STA in the STA MLD to periodically listen for the corresponding AP to have multicast service. That is, in this implementation, one station of the STA MLD can know whether each AP has multicast service, thereby saving the power consumption of the STA MLD.

[0011] In one implementation, each bit of the multicast service indication information corresponds to each AP in one or more APs of the AP MLD; each bit is used to indicate whether the AP corresponding to the bit has multicast service, or the value of each bit is used to indicate whether the AP corresponding to the bit has multicast service.

[0012] In another implementation, each bit of the multicast service indication information corresponds to each AP in the AP MLD; each bit is used to indicate whether the AP corresponding to the bit has multicast service, or the value of each bit is used to indicate whether the AP corresponding to the bit has multicast service.

[0013] In one implementation, the correspondence between each bit of the multicast service indication information and each AP of the AP MLD, or the correspondence between each bit of the multicast service indication information and each AP in one or more APs of the AP MLD, can be configured through the association response frame or management frame between the STA MLD and the AP MLD.

[0014] In another implementation, the correspondence between each bit of the multicast service indication information and each AP in the AP MLD, or the correspondence between each bit of the multicast service indication information and each AP in one or more APs of the AP MLD, is predefined. In another implementation, the multicast service indication information is a portion of the bits in the partial virtual bitmap field of the service indication bitmap TIM element.

[0015] In one implementation, the multicast service indication information is a portion of consecutive bits in the virtual bitmap field. For example, if the multicast service indication information is bits 1 to 7 in the virtual bitmap field, bits 1 to 7 in the virtual bitmap field can be used to indicate whether each AP of the AP MLD has multicast service.

[0016] In another embodiment, the multicast service indication information is a portion of non-contiguous bits in the virtual bitmap field. For example, if the multicast service indication information is bits 1, 2, and 4 in the virtual bitmap field, then bits 1, 2, and 4 in the virtual bitmap field can be used to indicate whether each AP of the AP MLD has multicast service.

[0017] In one implementation, the first AP of the AP MLD generates association identifier configuration information, which indicates the association identifier corresponding to each AP of the AP MLD; the first AP sends the association identifier configuration information. Each AP's AID corresponds to each bit of the multicast service indication information. That is, each bit of the multicast service indication information is used to indicate whether the AP with the corresponding AID has multicast service. This association identifier configuration information can be sent to the STA MLD via an association response frame or a management frame.

[0018] In another implementation, the AID corresponding to the first bit or the start bit of the portion of consecutive bits corresponding to the multicast service indication information is predefined. That is, the first bit or the start bit of this portion of consecutive bits is predefined. Alternatively, the start bit position of the multicast service indication information in the partial virtual bit map field of the TIM element is predefined. Alternatively, the AIDs of each AP in the AP MLD are continuously assigned starting from AIDx, and AIDx is predefined. In this implementation, the multicast service indication information is a portion of consecutive bits in the partial virtual bit map field of the service indication bitmap TIM element.

[0019] In the AP MLD, the association identifier assigned to each AP is different from the association identifier assigned to the site associated with each AP. That is, the association identifier assigned to each AP in the AP MLD cannot be reassigned by each AP to the sites it manages. However, the AIDs assigned by different APs to the sites they manage are relatively independent; that is, different APs can assign the same AID to the sites they manage.

[0020] Additionally, if one or more APs in the AP MLD are operating in multi-BSSID mode and are transmitting BSSIDs, then in both implementation methods described above, the AIDs of each AP in the AP MLD are continuously assigned starting from AIDx, where x equals max{2^(N1), 2^(N2), ..., 2^(N... y ), …, 2^(N) n )}; where n is the number of APs transmitting BSSIDs in the AP MLD, N y It is the value of the maximum basic service set identifier (BSSID) indicator field in the Multiple BSSID element of the AP broadcasting the y-th transmitting BSSID in the AP MLD.

[0021] Alternatively, in the AP MLD, the AIDs of each AP are continuously assigned starting from AIDx, where x equals max{2^(N1), 2^(N2), ..., 2^(N... y ), …, 2^(N) n)};n is the number of APs in the AP MLD, N y It is the value of the maximum basic service set identifier (BSSID) indicator field in the Multiple BSSID element broadcast by the y-th AP in the AP MLD, where the maximum BSSID indicator field value is 0 by default for non-transport APs or APs not operating in multiple BSSID mode.

[0022] In other words, the starting bit or the first bit of a subset of consecutive bits in the virtual bit field corresponding to the multicast service indication information is bit x, where x equals max{2^(N1), 2^(N2), ..., 2^(N... y ), …, 2^(N) n Alternatively, the AID corresponding to the first bit or the first bit of a contiguous set of bits in the virtual bit field corresponding to the multicast service indication information is AIDx, where x equals max{2^(N1), 2^(N2), ..., 2^(N... y ), …, 2^(N) n )}. Where n and N y The physical meaning can be found in the above description, and will not be elaborated here.

[0023] Furthermore, the multicast service indication information corresponds to a portion of the bits in the virtual bitmap field of the TIM element. Therefore, the first AP determines the offset and length fields in the TIM element based on the start byte N1 and end byte N2 in the service indication virtual bitmap field of the multicast service indication information; the first AP can then send these offset and length fields. This allows the stations associated with the first AP in the STA MLD to determine whether the AP corresponding to each bit of the multicast service indication information has multicast service based on the multicast service indication information, offset, and length fields.

[0024] Optionally, in this embodiment, the multicast service indication information can be compressed using an offset. In one implementation, if each bit of the multicast service indication information corresponds to an AP that is allocated sequentially according to the link identifier size of each AP in the AP MLD, and multiple APs with consecutive link identifiers do not have multicast services, then the multicast service indication information may only include the bits corresponding to other APs besides these multiple APs. That is, the multicast service indication information sent by the first AP may include the bits corresponding to other APs besides these multiple APs.

[0025] For ease of explanation, the multicast service indication information generated by the first AP is referred to as the first multicast service indication information, and the multicast service indication information sent by the first AP is referred to as the second multicast service indication information. The second multicast service indication information may be the same as the first multicast service indication information, or the second multicast service indication information may be a subset of the bits of the first multicast service indication information. The offset of the second multicast service indication information relative to the first multicast service indication information is simply referred to as the offset of the second multicast service indication information.

[0026] If the APs corresponding to the bits before byte N1 and all bits after byte N2 of the first multicast service indication information do not have multicast services, where N1 is greater than or equal to 0 and N2 is greater than or equal to 1, then the second multicast service indication information consists of all bits starting from byte N1 and ending at byte N2 of the first multicast service indication information.

[0027] Therefore, the length of the second multicast service indication information sent by the first AP is N2-N1+1; the offset of the second multicast service indication information is N1 / 2. Thus, when the station managed by the first AP in the STA MLD receives this length and offset, it can determine that the received second multicast service indication information is used to indicate whether the APs corresponding to bits N1*8 to ((N2+1)*8-1) have multicast services, and whether the APs corresponding to all bits from bit 0 to bit N1*8-1 do not have multicast services, and whether the APs corresponding to bit (N2+1)*8 and all bits thereafter do not have multicast services.

[0028] In this application, bit 'a' refers to the a-th bit, for example, bit 0 refers to the 0th bit.

[0029] If none of the APs corresponding to bits N0*8-1 to N1*8-1 of the first multicast service indication information have multicast services, and none of the APs corresponding to bits N2*8 and the bits thereafter also have multicast services, then the second multicast service indication information consists of the bits starting from byte 0 of the first multicast service indication information and ending at byte N0-1, plus the bits starting from byte N1 and ending at byte N2. Therefore, the length of the second multicast service indication information sent by the first AP is N0+N2-N1+1, and the offset is N1-N0. Consequently, when the station managed by the first AP in the STA MLD receives this length and offset, it can determine that the received second multicast service indication information indicates whether the APs corresponding to bits 0 to (N0-1)*8-1 and bits (N1-1)*8+1 to N2*8+1 have multicast services, while none of the APs corresponding to bits (N0-1)*8 to (N1-1)*8 have multicast services.

[0030] In another implementation, when multiple APs with consecutive associated identifiers do not have multicast services, the virtual bitmap fields may omit the bits corresponding to these associated identifiers. This involves using the offset in the TIM element to reduce the number of bits representing multicast service indication information in some virtual bitmap fields. Assume the multicast service indication information is represented by a portion of the virtual bitmap fields in the TIM element.

[0031] If the AP corresponding to the AID of the bits before byte N1 and all bits after byte N2 in the Service Indication Virtual Bitmap field does not have multicast service, where N1 is greater than or equal to 0 and N2 is greater than or equal to 1, then the multicast service indication information is all bits starting from byte N1 and ending at byte N2 in the Service Indication Virtual Bitmap field. Therefore, the length field of the TIM element sent by the first AP is N2-N1+1+3 and the offset of the TIM element is (1 / 2)N1. Furthermore, the station managed by the first AP in the STA MLD determines, based on the received length and offset, whether the multicast service indication information is used to indicate whether the APs corresponding to the AIDs of bits N1*8 to ((N2+1)*8-1) have multicast service, and determines that the APs corresponding to the AIDs of all bits from bit 0 to bit N1*8-1 do not have multicast service, and the APs corresponding to the AIDs of bit (N2+1)*8 and all bits after it do not have multicast service.

[0032] If none of the APs corresponding to the AIDs of all bits in the Service Indication Virtual Bitmap field (bytes N0 to N1-1) have multicast services, then the multicast service indication information consists of the bits starting from byte 0 and ending at byte N0-1, and the bits starting from byte N1 and ending at byte N2. Therefore, the length field of the TIM element sent by the first AP is N0+N2-N1+1+3, and the offset of the TIM element is (N1-N0)1 / 2. Consequently, the station managed by the first AP in the STA MLD can determine, based on this length field and offset of the received TIM element, whether the APs corresponding to the AIDs of bits 0 to (N0-1)*8-1 and (N1-1)*8+1 to N2*8+1 have multicast services, and that none of the APs corresponding to the AIDs of bits (N0-1)*8 to (N1-1)*8 have multicast services.

[0033] Optionally, the multicast service indication information sent by the first AP is carried in the Service Indication Bitmap (DTIM) beacon frame. Further, the first AP sends the multicast service after the DTIM beacon frame.

[0034] Optionally, for beacon frames, this multicast service indication information may be carried only in DTIM beacon frames. Optionally, this multicast service indication information may also be carried in other frames such as TIM beacon frames, management frames, data frames, and control frames.

[0035] Optionally, if the multicast service indication information is carried in a TIM beacon frame, management frame, data frame, or control frame, and if the first AP has a multicast service, the first AP can also send a service indication bitmap DTIM beacon frame and the multicast service following the DTIM beacon frame.

[0036] Secondly, this application also provides a method for multicast service transmission applicable to multiple links, described from the perspective of a site multi-link device (STA MLD). In this method, the first site (STA) of the STA MLD receives multicast service indication information from an AP MLD, the multicast service indication information being used to indicate whether one or more APs of the AP MLD have multicast services.

[0037] Optionally, the first STA can determine or know whether one or more APs have multicast services based on the multicast service indication information.

[0038] In one implementation, multicast service indication information is used to indicate whether an AP in an AP MLD has multicast services, and this AP is either a first AP or another AP in the AP MLD. In this implementation, the first STA can know whether the first AP or other APs in the AP MLD have multicast services, improving the flexibility of multicast service notification.

[0039] In another implementation, the multicast service indication information is used to indicate whether each AP in the AP MLD has multicast service. In this implementation, the first STA can know whether multiple APs have multicast service, avoiding the need for each STA in the STA MLD to periodically listen for multicast service in its corresponding AP, thereby saving power consumption of the STA MLD.

[0040] In another implementation, the multicast service indication information is used to indicate whether each AP in the AP MLD has multicast service. In this implementation, the first STA can know whether each AP in the AP MLD has multicast service, avoiding the need for each STA in the STA MLD to periodically listen for multicast service in its corresponding AP, thereby saving power consumption of the STA MLD.

[0041] In one implementation, the first STA of the STA MLD is a station operating on the main link. The first STA of the STA MLD receives multicast service indication information from the AP MLD, including: the first STA of the STA MLD listens on the main link for multicast service indication information from an AP of the AP MLD.

[0042] Optionally, for beacon frames, this multicast service indication information may be carried only in DTIM beacon frames.

[0043] Optionally, the multicast service indication information may be carried in other frames such as TIM beacon frames, management frames, data frames, or control frames.

[0044] Optionally, the multicast service indication information is carried in other frames such as TIM beacon frames, management frames, data frames, or control frames. The first STA can receive the DTIM beacon frame and receive the multicast service after the DTIM beacon frame. Correspondingly, for other STAs in the STAMLD, if they know from the multicast service indication information that the corresponding AP also has multicast service, then the other STAs can receive the DTIM beacon frame and receive the multicast service after the DTIM beacon frame.

[0045] Optionally, the multicast service is carried in the DTIM beacon frame, and the first STA can receive the multicast service after the DTIM beacon frame; correspondingly, for other STAs in the STA MLD, if they know from the multicast service indication information that the corresponding AP also has a multicast service, then the other STAs can receive the DTIM beacon frame and receive the multicast service after the DTIM beacon frame.

[0046] In another implementation, if the first STA determines that the AP on the link where the first STA is operating has multicast service, then it can receive the Transmit Service Indication Bitmap (DTIM) beacon frame from the AP and the multicast service following the DTIM beacon frame on that link.

[0047] In one embodiment, each bit of the multicast service indication information corresponds to each AP in the AP MLD; the value of each bit is used to indicate whether the AP corresponding to that bit has multicast service. For a detailed description of this embodiment, please refer to the relevant content in the first aspect above, which will not be elaborated here.

[0048] In another implementation, the multicast service indication information is a portion of the bits in the virtual bitmap field of the Service Indication Bitmap (TIM) element. For a detailed explanation of this implementation, please refer to the relevant content in the first aspect above, which will not be elaborated upon here.

[0049] In another embodiment, the multicast service indication information is a portion of consecutive bits in the virtual bitmap field of the Service Indication Bitmap (TIM) element. For a detailed description of this embodiment, please refer to the relevant content of the first aspect above, which will not be elaborated upon here.

[0050] Because some bits in the virtual bitmap field correspond to AIDs that are assigned to sites, and these bits are used to indicate whether the corresponding site has unicast services, in this implementation, the association identifier assigned to each AP in the AP MLD is different from the association identifier assigned to the site associated with each AP. That is, the association identifier assigned to each AP in the AP MLD cannot be reassigned by each AP to the sites it manages. However, the AIDs assigned by different APs to the sites they manage are relatively independent; that is, different APs can assign the same AID to the sites they manage.

[0051] In one embodiment, the first STA in the STA MLD receives association identifier configuration information, which indicates the association identifier (AID) corresponding to each AP in the AP MLD; the AID of each AP corresponds to each bit of the multicast service indication information; the first STA determines the AID corresponding to each AP in the AP MLD based on the association identifier configuration information. For a more detailed description of this embodiment, please refer to the relevant content of the first aspect above, which will not be elaborated here.

[0052] In another implementation, the AID corresponding to the first bit of the consecutive bits in the virtual bitmap field corresponding to the multicast service indication information is predefined. For a detailed explanation of this implementation, please refer to the relevant content in the first aspect above, which will not be elaborated upon here.

[0053] In another embodiment, the AID corresponding to the first bit of the partial consecutive bits is AIDx; where x equals max{2^(N1), 2^(N2), ..., 2^(N... y ), …, 2^(N) n )}; where n is the number of APs with transmission basic service set identifiers in the AP MLD, N y It is the value of the largest basic service set identifier (BSSID) indicator field in the Multiple BSSID element broadcast by the APy transmitting the BSSID. y This is the y-th AP transmitting its BSSID in the AP MLD. For a detailed explanation of this implementation, please refer to the relevant content in the first aspect above; it will not be elaborated upon here.

[0054] Optionally, in this embodiment, the multicast service indication information can be compressed using an offset. In one implementation, if each bit of the multicast service indication information corresponds to an AP allocated sequentially according to the link identifier size of each AP in the AP MLD, and multiple APs with consecutive link identifiers do not have multicast services, then the multicast service indication information may only include bits corresponding to APs other than those multiple APs. That is, the multicast service indication information sent by the first AP may include bits corresponding to APs other than those multiple APs. For a detailed description of this implementation, please refer to the relevant content of the first aspect above, which will not be elaborated here.

[0055] Thirdly, this application provides an access point for an access point multi-link device. This access point has some or all of the functions of the first AP in the AP MLD example described in the first aspect above. For example, the access point of the access point multi-link device may have some or all of the functions in some or all of the embodiments in this application, or it may have the functions of any one embodiment in this application implemented individually. The functions can be implemented by hardware or by hardware executing corresponding software. The hardware or software includes one or more units or modules corresponding to the above functions.

[0056] In one implementation, the access point of the access point multi-link device may include a processing unit and a communication unit. The processing unit is configured to support the access point of the access point multi-link device in performing the corresponding functions in the above-described method. The communication unit is used to support communication between the access point of the access point multi-link device and other devices. The access point of the access point multi-link device may also include a storage unit, which is coupled to the processing unit and the sending unit, and stores the necessary computer programs and data of the access point multi-link device.

[0057] In one embodiment, the access point of the access point multi-link device includes:

[0058] The processing unit is used to generate multicast service indication information, which is used to indicate whether one or more APs of APMLD have multicast services.

[0059] The communication unit is used to send the multicast service indication information.

[0060] As can be seen, in the access point of this multi-link device, the multicast service indication information generated by the processing unit can indicate whether it or other APs have multicast services, and then be sent by the communication unit to the site multi-link device. This allows any site in the site multi-link device to listen to the multicast service indication information, improving the flexibility of multicast service notification. In addition, when the multicast service indication information indicates whether each or more APs in the AP MLD have multicast services, it allows any site in the site multi-link device to know whether multiple APs have multicast services, avoiding the need for each site in the site multi-link device to check whether there are multicast services on its own link, thereby saving power consumption of the site multi-link device.

[0061] As an example, the processing unit can be a processor, the communication unit can be a transceiver or a communication interface, and the storage unit can be a memory.

[0062] In another embodiment, the access point of the access point multi-link device includes:

[0063] The processor is used to generate multicast service indication information, which is used to indicate whether one or more APs of APMLD have multicast services.

[0064] The transceiver is used to send the multicast service indication information.

[0065] As can be seen, in the access point of this multi-link device, the multicast service indication information generated by the processor can indicate whether it or other APs have multicast services, and then be sent by the transceiver to the site multi-link device. This allows any site in the site multi-link device to listen for this multicast service indication information, improving the flexibility of multicast service notification. In addition, when this multicast service indication information indicates whether each or more APs in the AP MLD have multicast services, it allows any site in the site multi-link device to know whether multiple APs have multicast services, avoiding the need for each site in the site multi-link device to check whether there are multicast services on its own link, thus saving power consumption of the site multi-link device.

[0066] Optionally, the access point of the multi-link device can also implement any one or more of the first aspects described above, which will not be detailed here.

[0067] Fourthly, this application also provides a site for a site multi-link device. This site has some or all of the functions of the first STA of the STA MLD described in the example of the method described in the second aspect above. For example, the site of the site multi-link device may have the functions of some or all of the embodiments in this application, or it may have the functions of any one embodiment in this application implemented individually. The functions can be implemented by hardware or by hardware executing corresponding software. The hardware or software includes one or more units or modules corresponding to the above functions.

[0068] In one embodiment, the site structure of the multi-link device may include a processing unit and a communication unit. The processing unit is configured to support the site of the multi-link device in performing the corresponding functions in the above-described method. The communication unit is used to support communication between the site of the multi-link device and other devices. The site of the multi-link device may also include a storage unit, which is coupled to the processing unit and the transmitting unit, and stores the necessary computer programs and data of the site of the multi-link device.

[0069] In one embodiment, the site of the site multi-link device includes:

[0070] The communication unit is configured to receive multicast service indication information from the AP MLD, the multicast service indication information being used to indicate whether one or more APs of the AP MLD have multicast services.

[0071] Optionally, the site for the multi-link device may also include a processing unit;

[0072] The processing unit is used to determine whether one or more APs have multicast services based on the multicast service indication information.

[0073] As can be seen, in the multi-link device of this site, the processing unit can determine whether one or more APs are providing multicast services based on the multicast service indication information. In other words, the multi-link device of this site can not only determine whether its own associated APs are providing multicast services, but also whether other APs in the AP MLD are providing multicast services, thus improving the flexibility of multicast service notification. Furthermore, the multicast service indication information indicates whether multiple APs or each AP in the AP MLD are providing multicast services. This means that any STA in the multi-link device of this site can determine whether multiple APs or each AP in the AP MLD are providing multicast services, avoiding the need for each STA in the STA MLD to listen for multicast service information, thus saving power consumption for the STA MLD.

[0074] As an example, the processing unit can be a processor, the communication unit can be a transceiver or a communication interface, and the storage unit can be a memory.

[0075] In another embodiment, the site of the site multi-link device includes:

[0076] The transceiver is used to receive multicast service indication information from the AP MLD, the multicast service indication information being used to indicate whether one or more APs of the AP MLD have multicast services.

[0077] Optionally, the site for the multi-link device may also include a processor;

[0078] The processor is configured to determine whether one or more APs have multicast services based on the multicast service indication information.

[0079] As can be seen, in this multi-link device, the processor can determine whether one or more APs are providing multicast services based on the multicast service indication information. In other words, the multi-link device can not only determine whether its own associated APs are providing multicast services, but also whether other APs in the AP MLD are providing multicast services, thus improving the flexibility of multicast service notification. Furthermore, the multicast service indication information indicates whether multiple APs or each AP in the AP MLD are providing multicast services; that is, any STA in the STA MLD can determine whether multiple APs or each AP in the AP MLD are providing multicast services, avoiding the need for each STA in the STA MLD to listen for multicast service information from its corresponding AP, thus saving power consumption for the STA MLD.

[0080] Optionally, the site of the multi-link device can also implement any one or more of the second aspect described above, which will not be detailed here.

[0081] Fifthly, embodiments of the present invention provide a computer-readable storage medium for storing a computer program, which, when run in a communication device, executes the multicast service transmission method applicable to multiple links described in the first aspect.

[0082] In a sixth aspect, embodiments of the present invention provide a computer-readable storage medium for storing a computer program, which, when run in a communication device, executes the multicast service transmission method applicable to multiple links described in the second aspect above.

[0083] In a seventh aspect, this application also provides a computer program product including a computer program, which, when run on a communication device, causes the communication device to perform the multicast service transmission method applicable to multiple links described in the first aspect.

[0084] Eighthly, this application also provides a computer program product including a computer program, which, when run on a communication device, causes the communication device to perform the multicast service transmission method applicable to multiple links described in the second aspect above.

[0085] Ninthly, this application provides a chip system including at least one processor and an interface for supporting any AP of the AP MLD, such as a first AP, to implement the functions involved in the first aspect, for example, determining or processing at least one of the data and information involved in the above methods. In one possible design, the chip system further includes a memory for storing computer programs and data necessary for the AP of the AP MLD. The chip system may be composed of chips or may include chips and other discrete devices.

[0086] In a tenth aspect, this application provides a chip system including at least one processor and an interface for supporting any STA of the STA MLD, such as a first STA, to implement the functions involved in the second aspect, for example, determining or processing at least one of the data and information involved in the above methods. In one possible design, the chip system further includes a memory for storing computer programs and data necessary for the STA of the STA MLD. The chip system may be composed of chips or may include chips and other discrete devices. Attached Figure Description

[0087] Figure 1 This is a schematic diagram of the structure of an AP MLD and a STA MLD provided in an embodiment of this application;

[0088] Figure 2 This is a schematic diagram of a frame format of a TIM element provided in an embodiment of this application;

[0089] Figure 3(a) is a schematic diagram of the structure of a communication system 100 provided in an embodiment of this application;

[0090] Figure 3(b) is a schematic diagram of the structure of a communication system 200 provided in an embodiment of this application;

[0091] Figure 3(c) is a schematic diagram of the structure of a communication system 300 provided in an embodiment of this application;

[0092] Figure 4 This is a schematic diagram of a multicast service transmission method 100 provided in an embodiment of this application;

[0093] Figure 5 This is a flowchart illustrating a multicast service transmission method 200 applicable to multiple links provided in an embodiment of this application.

[0094] Figure 5a This is a schematic diagram of the MLD parameter field in a multicast service transmission method applicable to multiple links provided in an embodiment of this application;

[0095] Figure 5b This is a schematic diagram of the capability information field in a multicast service transmission method applicable to multiple links provided in an embodiment of this application;

[0096] Figure 5c This is a schematic diagram of another capability information field in a multicast service transmission method applicable to multiple links provided in an embodiment of this application;

[0097] Figure 5d This is a schematic diagram of an RNR element in a multicast service transmission method applicable to multiple links provided in an embodiment of this application;

[0098] Figure 5e This is a schematic diagram of the TBTT information field in a multicast service transmission method applicable to multiple links provided in an embodiment of this application;

[0099] Figure 6 This is a schematic diagram of a multicast service transmission method 300 applicable to multiple links provided in an embodiment of this application;

[0100] Figure 7 This is a flowchart illustrating a multicast service transmission method 400 applicable to multiple links provided in an embodiment of this application.

[0101] Figure 8 This is a schematic diagram of a partial virtual bitmap field provided in an embodiment of this application;

[0102] Figure 9 This is a schematic diagram of a multicast service transmission method 500 applicable to multiple links provided in an embodiment of this application;

[0103] Figure 10 This is a schematic diagram of the frame format of a BSSID element provided in an embodiment of this application;

[0104] Figure 11 This is a schematic diagram of the structure of a communication device 100 provided in an embodiment of this application;

[0105] Figure 12 This is a schematic diagram of the structure of a communication device 200 provided in an embodiment of this application;

[0106] Figure 13 This is a schematic diagram of the structure of a communication device 300 provided in an embodiment of this application;

[0107] Figure 14 This is a schematic diagram of the structure of a chip provided in an embodiment of this application. Detailed Implementation

[0108] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.

[0109] To better understand the multicast service transmission method and related apparatus applicable to multiple links disclosed in the embodiments of this application, the relevant concepts of the embodiments of this application are first described.

[0110] 1. Multi-link devices

[0111] The wireless communication system applicable to the embodiments of this application can be a wireless local area network (WLAN) or a cellular network. The multicast service transmission method can be implemented by a communication device in the wireless communication system or a chip or processor in the communication device. The communication device can be a wireless communication device that supports parallel transmission across multiple links, for example, called a multi-link device or a multi-band device. Compared to devices that only support single-link transmission, multi-link devices have higher transmission efficiency and higher throughput.

[0112] A multi-link device includes one or more affiliated STAs. An affiliated STA is a logical site that can operate on a single link. The affiliated site can be an Access Point (AP) or a non-Access Point Station (non-AP STA). For ease of description, this application refers to a multi-link device with an affiliated AP as a multi-link AP, a multi-link AP device, or an AP multi-link device (AP MLD), and a multi-link device with an affiliated non-AP STA as a multi-link STA, a multi-link STA device, or a STA multi-link device (STA MLD). For ease of description, "a multi-link device includes affiliated STAs" is also briefly described in this embodiment as "a multi-link device includes STAs."

[0113] It is worth noting that a multi-link device includes multiple logical sites, each of which operates on a single link, but multiple logical sites are allowed to operate on the same link.

[0114] Multilink devices can implement wireless communication by following the 802.11 series of protocols. For example, they can follow Extremely High Throughput (EHT) stations or 802.11be-based or compatible stations to communicate with other devices. Of course, other devices can be multilink devices or not.

[0115] For example, the multi-link device in the embodiments of this application can be a single-antenna device or a multi-antenna device. For instance, it can be a device with two or more antennas. The embodiments of this application do not limit the number of antennas included in the multi-link device. In the embodiments of this application, the multi-link device can allow services of the same access type to be transmitted on different links, and even allow the same data packets to be transmitted on different links; it can also disallow services of the same access type to be transmitted on different links, but allow services of different access types to be transmitted on different links.

[0116] For example, a multi-link device is a device with wireless communication capabilities. This device can be a complete machine or a chip or processing system installed in a complete machine. Devices with these chips or processing systems installed can implement the methods and functions of the embodiments of this application under the control of these chips or processing systems. For example, the STA MLD in the embodiments of this application has wireless transceiver capabilities and can support the 802.11 series of protocols, enabling communication with AP MLDs or other STAMLDs or single-link devices. For example, the STA MLD is any user communication device that allows users to communicate with APs and thus with WLANs. For example, the STA MLD can be a user device that can connect to the Internet, such as a tablet, desktop, laptop, notebook computer, ultra-mobile personal computer (UMPC), handheld computer, netbook, personal digital assistant (PDA), or mobile phone, or an IoT node in the Internet of Things, or an in-vehicle communication device in the Internet of Vehicles. The STA MLD can also be a chip and processing system in the aforementioned terminals.

[0117] The AP MLD in this application embodiment is a device that provides services to the STA MLD and can support the 802.11 series of protocols. For example, the AP MLD can be a communication server, router, switch, bridge, or other communication entity. Alternatively, the AP MLD can include various forms of macro base stations, micro base stations, relay stations, etc. Of course, the AP MLD can also be the chip and processing system in these various forms of devices, thereby realizing the methods and functions of this application embodiment. Furthermore, multi-link devices can support high-speed, low-latency transmission. With the continuous evolution of wireless LAN application scenarios, multi-link devices can be applied to more scenarios, such as sensor nodes in smart cities (e.g., smart water meters, smart electricity meters, smart air quality monitoring nodes), smart devices in smart homes (e.g., smart cameras, projectors, displays, televisions, speakers, refrigerators, washing machines, etc.), nodes in the Internet of Things (IoT), entertainment terminals (e.g., AR, VR wearable devices), smart devices in smart offices (e.g., printers, projectors, etc.), vehicle-to-everything (V2X) devices, and some infrastructure in daily life scenarios (e.g., vending machines, supermarket self-service navigation kiosks, self-checkout machines, self-service ordering machines, etc.). This application embodiment does not impose special restrictions on the specific forms of STA MLD and AP MLD; these are merely illustrative examples. The 802.11 protocol can be a protocol that supports or is compatible with 802.11be.

[0118] The frequency bands in which multi-link devices can operate may include, but are not limited to: sub 1GHz, 2.4GHz, 5GHz, 6GHz and high frequency 60GHz.

[0119] For example, the multi-link device in the embodiments of this application can be a single-antenna device or a multi-antenna device. For instance, the multi-link device in the embodiments of this application can be a device with two or more antennas. The embodiments of this application do not limit the number of antennas included in the multi-link device. Figure 1 The diagram shows the structure of AP MLD with multiple antennas and STA MLD with a single antenna. The 802.11 standard focuses on the physical layer (PHY) and media access control (MAC) layer in AP MLD and STA MLD.

[0120] 2. Link Identifier

[0121] A link identifier represents a station operating on a link. In other words, if there is more than one station on a link, more than one link identifier is needed to represent them. The link mentioned below sometimes also refers to the station operating on that link.

[0122] During data transmission, AP MLD and STA MLD can use link identifiers to identify a link or stations on a link. Before communication, AP MLD and STA MLD can negotiate or communicate the correspondence between link identifiers and links or stations on links. Therefore, during data transmission, it is not necessary to transmit a large amount of signaling information to indicate links or stations on links; carrying the link identifier is sufficient, reducing signaling overhead and improving transmission efficiency.

[0123] In one example, the management frames sent by the AP MLD when establishing a basic service set (BSS), such as beacon frames, carry an element that includes multiple link identification information fields. These fields indicate the correspondence between a link identifier and a station operating on the corresponding link. The link identification information field includes not only the link identifier but also one or more of the following: Media Access Control (MAC) address, operation set, and channel number. One or more of these elements can identify a link. For the AP, the AP's MAC address is its BSSID (basic service set identifier). In another example, during multi-link device association, the AP MLD and STA multi-link devices negotiate multiple link identification information fields. Multi-link device association refers to one association between one AP of the AP MLD and one STA of the STA MLD. This association allows multiple STAs of the STA MLD to associate with multiple APs of the AP MLD, with each STA associated with one AP.

[0124] In subsequent communications, the AP MLD or STA multi-link device will use a link identifier to represent a station within the STA multi-link device. The link identifier can also represent one or more attributes of the station, including its MAC address, operating set, and channel number. The MAC address can be replaced with the association identifier of the associated AP MLD. Optionally, if multiple stations operate on a single link, the link identifier (a numeric ID) represents not only the operating set and channel number of the link but also the identifier of the station operating on that link, such as the station's MAC address or association identifier (AID).

[0125] 3. Business Indicator Bitmap Elements

[0126] Both Traffic Indication Map (TIM) beacon frames and Delivery Traffic Indication Map (DTIM) beacon frames carry Traffic Indication Map (TIM) elements. The frame format of the TIM element field is as follows: Figure 2 As shown, where:

[0127] Element identifier (ID) field: used for identification Figure 2 The element shown is a TIM element.

[0128] Length field: Used to indicate the length of the TIM element. The total length after calculating this field is the total length of the DTIM count field, DTIM period field, bitmap control field, and part of the virtual bitmap field, in bytes.

[0129] The DTIM count field indicates how many TIM beacon frames are remaining before the next DTIM beacon frame arrives, even for the current beacon frame carrying this TIM element. In other words, the DTIM count field is a count value that changes. When the value of the DTIM count field is 0, it indicates that the current beacon frame is a DTIM beacon frame; when the value of the DTIM count field is not 0 or is non-zero, it indicates that the current beacon frame is a TIM beacon frame.

[0130] The DTIM period field indicates the duration of the DTIM beacon frame period, i.e., the arrival interval, which is measured in units of the DTIM beacon frame period. For example, if the DTIM period is set to 1, then the DTIM count in each TIM element field is equal to 0, meaning that each beacon frame is a DTIM beacon frame.

[0131] Bitmap control field: such as Figure 2 As shown, bit 0 in the Bitmap control field is used to indicate whether the access point (AP) sends multicast data services after sending the DTIM beacon frame. In other words, if bit 0 in the Bitmap control field of the DTIM beacon frame indicates whether the AP buffers multicast services and whether the multicast service is not sent through the multicast AID; bits 1 to 7 in the Bitmap control field are used to indicate the offset of the partial virtual bitmap, which is in bytes (i.e., 8 bits).

[0132] Partial Virtual Bitmap: Each bit in the partial virtual bitmap field corresponds to an association identifier (AID), used to indicate whether the site corresponding to that AID has unicast services. Alternatively, each bit in the partial virtual bitmap field corresponds to a multicast AID, used to indicate whether a group of sites corresponding to the multicast AID has downlink services. The partial virtual bitmap field is a subset of the tracecindication virtual bitmap field, which is 251 bytes long and used to indicate whether the sites corresponding to AID 0 to AID 2007 have downlink services.

[0133] The element ID field, length field, DTIM count field, DTIM period field, and bitmap control field each occupy 1 byte.

[0134] Although the embodiments in this application are primarily illustrated using an IEEE 802.11-based network as an example, those skilled in the art will readily understand that the various aspects of this application can be extended to other networks employing various standards or protocols, such as BLUETOOTH, high-performance radio LAN (HIPERLAN) (a wireless standard similar to IEEE 802.11, primarily used in Europe), and wide area networks (WANs), wireless local area networks (WLANs), personal area networks (PANs), or other networks now known or developed in the future. Therefore, regardless of the coverage area and wireless access protocol used, the various aspects provided in this application can be applied to any suitable wireless network.

[0135] Figure 3(a) illustrates a communication system 100 applied in this application embodiment, using a wireless local area network (WLAN) as an example. The communication system 100 includes a station 101 and a station 102. Station 101 and station 102 can communicate via multiple links to improve throughput. Station 101 can be a multi-link device, and station 102 can be a single-link device or a multi-link device, etc. In one scenario, station 101 is an AP MLD, and station 102 is a STA MLD or a station (e.g., a single-link station). In another scenario, station 101 is a STA MLD, and station 102 is an AP (e.g., a single-link AP) or an AP MLD. In yet another scenario, station 101 is an AP MLD, and station 102 is an AP MLD or an AP; in yet another scenario, station 101 is a STA MLD, and station 102 is a STA MLD or a STA (e.g., a single-link station). Of course, the WLAN may also include other devices. The number and types of devices illustrated in Figure 3(a) are merely exemplary.

[0136] Figures 3(b) and 3(c) show schematic diagrams of the communication system 200 and communication system 300, respectively. The communication system 200 and communication system 300 are illustrated using the example of a multi-link device in a wireless local area network communicating with other devices through multiple links.

[0137] Figure 3(b) illustrates a scenario of communication between AP MLD and STA MLD. AP MLD includes AP1 and AP2, and STA MLD includes STA1 and STA2. AP MLD and STA MLD communicate in parallel using link 1 and link 2.

[0138] Figure 3(c) illustrates a scenario where AP MLD601 communicates with STAs MLD602, MLD603, and STA604. AP MLD601 includes subordinate APs 601-1 to 601-3; STA MLD602 includes three subordinate STAs: STA602-1, STA602-2, and STA602-3; STA MLD603 includes two subordinate STAs: STA603-1 and STA603-2; STA604-1 and STA604 are single-link devices. AP MLD601 can communicate with STA MLD602 via links 1, 2, and 3; communicate with STA MLD603 via links 2 and 3; and communicate with STA604 via link 1. In one example, STA604 operates in the 2.4 GHz band; in STA MLD603, STA603-1 operates in the 5 GHz band, and STA603-2 operates in the 6 GHz band; in STA MLD602, STA602-1 operates in the 2.4 GHz band, STA602-2 operates in the 5 GHz band, and STA602-3 operates in the 6 GHz band. AP601-1 in AP MLD601, operating in the 2.4 GHz band, can transmit uplink or downlink data with STA604 and STA602-2 in STA MLD602 via link 1. AP601-2 in AP MLD601, operating in the 5 GHz band, can transmit uplink or downlink data with STA603-1 in STA MLD603, operating in the 5 GHz band, via link 2, and can also transmit uplink or downlink data with STA602-2 in STA MLD602, operating in the 5 GHz band, via link 2. AP601-3, operating in the 6GHz band in AP MLD601, can transmit uplink or downlink data with STA602-3, operating in the 6GHz band in STA MLD602, via link 3. It can also transmit uplink or downlink data with STA603-2 in STA MLD via link 3.

[0139] It should be noted that Figure 3(b) only shows that the AP MLD supports two frequency bands, and Figure 3(c) only illustrates that the AP MLD601 supports three frequency bands (2.4GHz, 5GHz, 6GHz), with each frequency band corresponding to one link. The AP MLD601 can operate on one or more links among Link 1, Link 2, or Link 3. On the AP side or STA side, the link here can also be understood as the station operating on that link. In practical applications, the AP MLD and STA MLD can also support more or fewer frequency bands, that is, the AP MLD and STA MLD can operate on more or fewer links. This application embodiment does not limit this.

[0140] Currently, single-link devices, such as STAs in energy-saving mode, determine whether multicast traffic indication (DTIM) beacon frames are expected after sending a DTIM beacon frame by periodically listening to DTIM beacon frames and using bit 0 in the bitmap control field. However, in multi-link scenarios, if bit 0 in the bitmap control field is also used to determine whether multicast traffic indication (DTIM) is expected after a DTIM beacon frame, then... Figures 3(a) to 3(c) In the communication system shown, each STA in the STA MLD periodically listens for TIM beacon frames on the link. By checking the value of bit 0 in the bitmap control field of the TIM beacon frame it listens for, it determines whether the AP on that link will send multicast service after sending the DTIM beacon frame. If multicast service is available, the STA receives the multicast service sent by the AP after the corresponding DTIM beacon frame. This multicast service is sent immediately after the DTIM beacon frame, for example, after the SIFS (short inter-framespace) interval from the end of the DTIM beacon frame.

[0141] In the 802.11 protocol, a STA typically has two operating modes: a non-energy-saving mode and an energy-saving mode. When a STA operates in non-energy-saving mode, it remains in an active state (also known as a wake-up state) regardless of whether data is being transmitted. When a STA operates in energy-saving mode, it remains in an active state when transmitting data with the AP; otherwise, it remains in a doze state to conserve power. Whether a STA is in energy-saving mode can be determined by sending a frame to the AP. Setting the energy-saving bit in the frame control field of the MAC header to 1 indicates that the STA is in energy-saving mode, while setting it to 0 indicates that the STA is in non-energy-saving mode.

[0142] like Figure 4The multicast service transmission method 100 shown in Figure 3(c) takes communication between AP MLD601 and STA MLD602 as an example. STA 602-1 of STA MLD602 needs to listen to TIM beacon frame 1 on link 1 to determine whether AP601-1 will send multicast service 1 after DTIM beacon frame 1 through bit 0 in the bit map control field of TIM beacon frame 1. STA 602-2 of STA MLD602 needs to listen to TIM beacon frame 2 on link 2 to determine whether AP601-2 will send multicast service 2 after DTIM beacon frame 2 through bit 0 in the bit map control field of TIM beacon frame 2. STA 602-3 of STA MLD602 needs to listen to TIM beacon frame 3 on link 3 to determine whether AP601-3 will send multicast service 3 after DTIM beacon frame 3 through bit 0 in the bit map control field of TIM beacon frame 3. It is evident that if the number of links in the STA MLD602 continues to increase, the power consumption of the STA MLD602 will increase significantly.

[0143] Therefore, how to reduce the power consumption of STA MLD has become an urgent problem to be solved.

[0144] The multicast service transmission method applicable to multiple links provided in this application can reduce the power consumption of STA MLD. The following is a detailed description with reference to the accompanying drawings.

[0145] The embodiments of this application are described in two examples, Example 1 and Example 2. The difference between Example 1 and Example 2 is that Example 1 focuses on how each bit of the multicast service indication information indicates whether the AP corresponding to that bit has multicast service; while Example 2 focuses on how the multicast service indication information is a portion of the bits in the partial virtual bitmap field of the TIM element.

[0146] Example 1

[0147] Figure 5 This application illustrates a method 200 for multicast service transmission applicable to multiple links, provided by an embodiment of the present application. This method 200 is illustrated using an example implemented in a communication system composed of an AP MLD and a STA MLD. The AP MLD includes one or more APs, with the first AP being any one of the APs; the STA MLD includes one or more STAs, with the first STA being any one of the STAs. As described above, a multi-link association can be established between the AP MLD and the STAMLD. This method 200 for multicast service transmission applicable to multiple links may include, but is not limited to, the following steps:

[0148] Step S201: The first AP of AP MLD generates multicast service indication information;

[0149] The first AP is any AP in AP MLD.

[0150] The multicast service indication information may be referred to as the multicast service indication field or multicast service indication, and this application embodiment does not limit it. The description of the multicast service indication information includes the following two statements: (1) The multicast service indication information is used to indicate whether one or more APs of AP MLD have multicast services; (2) The multicast service indication information is used to indicate whether one or more APs of AP MLD send multicast services after the DTIM beacon frame; In another example, the description of the multicast service indication information includes the following two statements: (3) The multicast service indication information is used to indicate whether one or more APs of AP MLD buffer multicast services; (4) The multicast service indication information is used to indicate that the multicast services of one or more APs of AP MLD are not sent out in the form of multicast AID. This application embodiment will use statement (1) as an example for subsequent explanation.

[0151] On the one hand, multicast services can include multicast management frames and multicast data frames, where the type of the frame is indicated by the type field identifier in the frame control field of the MAC header; on the other hand, multicast services can be divided into broadcast services and multicast services, that is, the multicast services sent by the AP are sent to the site associated with the AP or the site associated with the AP in the form of broadcast or multicast.

[0152] Within the same AP MLD, each AP independently transmits multicast management frames on its own operating link; each AP also transmits the same multicast data frames to each corresponding STA in its associated STA MLD on its own operating link. It is understood that the multicast management frames are link-level and do not need to be received by legacy sites on other links or by STA MLDs that have not established an association on that link, thus saving power consumption for the corresponding sites. Furthermore, each AP in the AP MLD transmitting the same multicast data frames on each link avoids the loss of multicast data frames by sites in single-radio STA MLDs, or in other words, avoids frequent link switching by single-radio STA MLDs to receive multicast data frames. In one optional implementation, multicast service indication information is used to indicate whether an AP in the AP MLD has multicast service. This AP can be the first AP or any other AP in the AP MLD besides the first AP. For example, in Figure 3(c), the first AP is AP601-1. The multicast service indication information generated by AP601-1 can be used to indicate whether AP601-2 in AP MLD601 has multicast service; or, the multicast service indication information generated by AP601-1 can be used to indicate whether AP601-1 in AP MLD601 has multicast service.

[0153] In another optional implementation, the multicast service indication information is used to indicate whether multiple APs in the AP MLD have multicast services. These multiple APs can be some or all APs in the AP MLD. For example, in Figure 3(c), the first AP is AP601-1, which generates the multicast service indication information. This multicast service indication information can be used to indicate whether AP601-1 and AP601-2 in AP MLD 601 have multicast services; or, the multicast service indication information can be used to indicate whether AP601-1, AP601-2, and AP601-3 in AP MLD 601 have multicast services.

[0154] In one optional implementation, each bit of the multicast service indication information corresponds to each AP in the AP MLD. The value of each bit indicates whether the AP corresponding to that bit has multicast service; or each bit indicates whether the AP corresponding to that bit has multicast service. Optionally, each bit of the multicast service indication information corresponds to each AP in the AP MLD according to the size of the link identifier operated by each AP in the AP MLD. In other words, the high-low order of the bits in the multicast service indication information corresponds to the size order of the link identifier, which is the link identifier operated by each AP in the AP MLD.

[0155] In another implementation, the bits of the multicast service indication information correspond one-to-one with each link (or each AP in the AP MLD). For example, each bit of the multicast service indication information is used together with each link identifier. Optionally, each bit of the multicast service indication information is located in the target beacon transmission time (TBTT) information field of the Reduced Neighbor Report (RNR) element. Specifically, the TBTT information field is supplemented with information such as... Figure 5a The MLD (Multi-Link Device) parameter subfield shown includes the Multi-Link Device ID, Link ID, Change Sequence, and Multicast Service Indicator. The Multi-Link Device ID indicates the MLD where the reported AP resides; the Link ID identifies the sequence number of the reported AP within the AP MLD; the Change Sequence indicates the update count value of the reported AP's critical BSS parameters; and the Multicast Service Indicator indicates whether the reported AP has multicast services, and this indicator can occupy 1 bit. Optionally, multicast services may include multicast management frame services and multicast data frame services. In one implementation, two fields are used to indicate the multicast management frame service and the multicast data frame service, for example, each occupying 1 bit. Specifically, these are called multicast management frame service indicator and multicast data frame service indicator, used to indicate whether the reported AP has the corresponding multicast management frame service and multicast data frame service, respectively. In another implementation, only one of the multicast management frame service and multicast data frame service can be indicated using one field. For example, the multicast management frame service indicator field can be used to indicate whether the reported AP has the corresponding multicast management frame service, or the multicast data frame service indicator field can be used to indicate whether the reported AP has the corresponding multicast data frame service.

[0156] Optionally, the AP sending the multicast service indication information can still indicate whether the AP is using downlink multicast services using the existing method, namely bit 0 in the bitmap control field of the TIM element.

[0157] Typically, RNR elements are used to enable unassociated sites to discover surrounding APs, while associated sites may ignore interpreting the RNR element. Therefore, this application provides a method to indicate whether there is a multicast service indication in the RNR element, which is implemented through the capability information field in the beacon frame or probe response frame. A multicast service flag is added to the capability information field to indicate whether at least one reported AP in the RNR element has multicast service. This multicast service flag can be indicated using 1 bit; for example, setting 1 bit of the multicast service flag to 1 indicates that at least one reported AP has multicast service. As an equivalent alternative, 1 bit can also be set to 0 to indicate that at least one reported AP has multicast service. See details. Figure 5b As shown, a multicast service flag is added to the capability information field in the probe response frame. When it indicates a value of "multicast service available", it can instruct associated or unassociated sites to interpret the RNR element. Figure 5b The capability information field shown may also include a Change Number Updated Flag (CSN updated flag), which indicates whether the value of the Change Number field of the reported AP has changed. When it indicates that at least one reported AP has changed its Change Number field value, it can instruct the associated or unassociated site to interpret the RNR element.

[0158] Or in another implementation, see Figure 5c As shown, an RNR flag is added to the capability element to indicate whether at least one reported AP has a changed sequence number field value or has multicast service. This indicates whether the station interprets the RNR element. The RNR flag can be represented by 1 bit. When the RNR flag is set to 1, it indicates that at least one reported AP has multicast service or that at least one reported AP has a changed sequence number field value, instructing associated or unassociated stations to interpret the RNR element. Alternatively, the RNR flag can be set to 1, or a value of 0 can be used to indicate that at least one reported AP has multicast service or that at least one reported AP has a changed sequence number field value.

[0159] The above Figure 5b and Figure 5cIn the two implementation methods shown, the capability information fields also include ESS (extended service set), IBSS (independent basic service set), Privacy, Short Preamble, Spectrum Management, QoS (quality of service), Short Slot Time, APSD (automatic powersave delivery), Radio Measurement, and EPD (Ethertype Protocol Discrimination), as detailed in the 802.11 REVmd D3.0 protocol. At the site end, such as associated sites or associated site MLDs, the 1-bit multicast service flag or 1-bit RNR flag added to the capability element in the beacon frame can be used to select whether to parse the RNR element, or to always parse the RNR element by default.

[0160] To better understand the embodiments of this application, the RNR elements mentioned in the above embodiments are explained as follows:

[0161] Reduced Neighbor Report Element: APs carry reduced neighbor report elements in management frames, such as beacon frames and probe response frames. During a scan, the STA receives management frames sent by APs and obtains information about surrounding APs based on the reduced neighbor report element, then selects a suitable AP to associate with.

[0162] Specifically, the RNR element typically carries one or more Neighbor AP info fields, which describe information about one or more neighboring APs and their respective BSSs. This information will be referred to below as the simplified neighboring AP information. Figure 5d The figure illustrates a simplified instruction format, including the fields of the simplified neighbor reporting element:

[0163] The TBTT (Target Beacon Transmission Time, TBTT) info header field carries the following information:

[0164] The TBTT info Field Type field indicates the type of TBTT info. Together with the TBTT info length field, it indicates the format of the TBTT info field.

[0165] The Filtered Neighbor AP field indicates whether the SSIDs of all BSSs carried in the Neighbor APinfo field match the SSIDs in the Probe Request frame.

[0166] Reserved field (1 bit).

[0167] The TBTT info count field indicates the number of TBTT info fields contained in the TBTT info set.

[0168] TBTT info Length field: Indicates the length of each TBTT info field. The specific information format for different lengths is shown in Table 1.

[0169] Table 1

[0170]

[0171]

[0172] The following shows the specific format of the TBTT info field when the TBTT information length is 12 bytes, such as... Figure 5e As shown:

[0173] Neighbor AP TBTT offset field: indicates the offset of the beacon transmission time between the neighboring AP and the reporting AP.

[0174] BSS Identifier (BSSID) field: Indicates the BSS identifier corresponding to this neighboring AP.

[0175] Short SSID field: Indicates the service set identifier to which the neighboring AP belongs.

[0176] 20MHz power spectral density indicates the power transmitted under default conditions, with units of dBm / MHz. Power spectral density (PSD) is equivalent isotropically radiated power (EIRP).

[0177] BSS Parameter field: Indicates relevant parameters of neighboring APs, such as... Figure 5e It contains the following information:

[0178] The recommended use field for the OCT (Option Channel Tunneling) mechanism indicates that the neighboring AP expects to exchange management-type MPDUs with it via the OCT mechanism.

[0179] Same SSID field: Indicates whether the neighboring AP and the reporting AP have the same SSID.

[0180] Multiple Basic Service Set Identifier (BSSID) field: Indicates whether the neighboring AP belongs to a set of multiple BSSIDs.

[0181] Transmitted BSSID field: If the neighboring AP is part of a multiple BSSID set, it further indicates whether the neighboring AP is a Transmitted BSSID or a non-transmitted BSSID.

[0182] The "Member Of ESS With 2.4 / 5GHz Co-Located AP" field indicates whether the neighboring AP is co-located with a 2.4 / 5GHz AP (i.e., not a 6GHz only AP) and is a member of an extended service set.

[0183] The Unsolicited Probe Response Active field indicates whether the neighboring AP has enabled active probe response.

[0184] Co-located AP field: Indicates whether the neighboring AP and the reporting AP are co-located.

[0185] For example, the MLD601 AP includes three APs. The multicast service indication information consists of three bits. These three bits correspond to the three APs in descending order of their respective link identifiers. Assuming the link identifiers of the three APs are as follows: AP601-1's link identifier is 3, AP601-2's is 2, and AP601-3's is 1, then the first bit of the multicast service indication information corresponds to AP601-1, the second bit to AP601-2, and the third bit to AP601-3. If the multicast service indication information is 011, it indicates that AP601-1 has no multicast service, while AP601-2 and AP601-3 do. Alternatively, these three bits can also correspond to the three APs in ascending order of their respective link identifiers.

[0186] In one optional implementation, the number of bits in the multicast service indication information can also be a fixed value. Of this fixed number of bits, all bits except those corresponding to the number of APs can be set to zero by default; for example, it can be fixed at 4 bits, where the first 3 bits (starting from the most significant bit) correspond to the 3 APs in the AP MLD, and the next bit is set to zero. That is, this fixed number of bits can be more than the number of APs in the AP MLD.

[0187] S202, The first AP sends the multicast service indication information;

[0188] S203, the first STA in STA MLD receives the multicast service indication information;

[0189] In this context, the first STA refers to a site managed by the first AP or a nearby site. Sites near the first AP include sites managed by the first AP and unassociated sites. The following description uses AP-managed sites as an example to illustrate the multicast service transmission method described in this application. Optionally, the first STA can be any site of the STA MLD, and can determine whether each AP or some APs in the AP MLD have multicast services. Therefore, any site of the STA MLD can receive multicast service indication information from its associated AP.

[0190] S204. The first STA determines whether one or more APs in the AP MLD have multicast services based on the multicast service indication information.

[0191] In one embodiment, the multicast service transmission method applicable to multiple links further includes: for an AP MLD with multicast service, the AP can send the multicast service after the next DTIM beacon frame to be sent after the multicast service indication information; correspondingly, a station of the STA MLD operating on the link of the AP can receive the DTIM beacon frame on the link and receive the subsequent multicast service. Specifically, a station of the STA MLD operating on the link of the AP can receive and parse the multicast management frame after the DTIM beacon frame on the link, and discard the multicast data frames after the DTIM beacon frames on other links not located on the link of the first STA. At this time, the first STA of the STA MLD has received the corresponding multicast data frame on its link. Optionally, the DTIM frame is the next DTIM beacon frame after the multicast service indication information. Optionally, if the first AP also has multicast services, the multicast service can be sent after the next DTIM beacon frame to be sent after the multicast service indication information; correspondingly, the first STA can receive the DTIM beacon frame after the multicast service indication information and receive the multicast service after the DTIM beacon frame.

[0192] In embodiments of the present invention, the multicast service indication information may be carried in management frames, such as beacon frames, TIM frames, data frames, or control frames, or other frames.

[0193] Optionally, the multicast service indication information can be located within a DTIM beacon frame, which is the same DTIM beacon frame containing the multicast service indication information. In other words, the multicast service indication information sent by the first AP can be located solely within a DTIM beacon frame. Specifically, for an AP MLD with multicast service, the AP can send the multicast service after the next DTIM beacon frame to be sent following the multicast service indication information. Correspondingly, the station corresponding to this AP, knowing from the multicast service indication information that the AP has multicast service, can receive the DTIM beacon frame and then receive the multicast service. Specifically, a station in the STA MLD operating on the link of this AP can receive and parse the multicast management frame following the DTIM beacon frame on that link, discarding multicast data frames following DTIM beacon frames on other links not on the link where the first STA is located. At this point, the first STA in the STA MLD has already received the corresponding multicast data frame on its link. Optionally, if the first AP also has multicast services, it can send multicast services after a DTIM beacon frame carrying multicast service indication information; correspondingly, the first STA can receive multicast services after a DTIM beacon frame carrying the multicast service indication information.

[0194] For example, assuming the communication system 300 shown in Figure 3(c), the multicast service indication information sent by AP601-2 in AP MLD601 is 111, and the first bit of this multicast service indication information corresponds to AP601-1, the second bit corresponds to AP601-2, and the third bit corresponds to AP601-3. As shown in Figure 3(c), AP601-2 communicates with STA603-1 in STA MLD603 and STA602-2 in STA MLD602 through link 2. Therefore, STA603-1 and STA602-2 can detect the multicast service indication information 111 sent by AP601-2.

[0195] In one implementation, for STA MLD602, STA602-2 can determine that AP601-1, AP601-2, and AP601-3 all have multicast services. Therefore, STA602-1, which operates on link 1 of AP601-1, listens for DTIM beacon frame 1 and subsequent multicast service 1; STA602-2, which operates on link 2 of AP601-2, listens for DTIM beacon frame 2 and subsequent multicast service 2; and STA602-3, which operates on link 3 of AP601-3, listens for DTIM beacon frame 3 and subsequent multicast service 3.

[0196] In another implementation, if the multicast service indication information is carried in the DTIM beacon frame, then STA602-2, which receives the DTIM beacon frame, can receive the multicast service after the DTIM beacon frame; while other STAs of STA MLD602 still need to receive the DTIM beacon frames on their respective links, as well as the subsequent multicast services.

[0197] Optionally, STA604 can also detect the multicast service indication information from Link 1. However, if STA604 does not care whether other APs indicated by the multicast service indication information have multicast services, it may not receive the multicast services from these APs. If STA604 cares whether other APs indicated by the multicast service indication information have multicast services, such as if STA604 has frequency band selection reception capability, then STA604 can know whether other APs have multicast services based on the multicast service indication information.

[0198] For STA MLD603, STA603-1 can determine that AP601-1, AP601-2, and AP601-3 all have multicast services. However, there is no station in STA MLD603 operating on link 1 of AP601-1. Therefore, STA603-1, operating on link 2 of AP601-2, listens for DTIM beacon frame 2 and subsequent multicast service 2; STA603-2, operating on link 3 of AP601-3, listens for DTIM beacon frame 3 and subsequent multicast service 3.

[0199] In another implementation, if the multicast service indication information is carried in the DTIM beacon frame, then STA603-1, which receives the DTIM beacon frame, can receive multicast services after the DTIM beacon frame; while other STAs of STA MLD603 still need to receive the DTIM beacon frames on their respective links, as well as the subsequent multicast services.

[0200] It is worth noting that the eavesdropping mentioned in this invention can also be understood as receiving.

[0201] Figure 6 This example illustrates a multicast service transmission method 300 suitable for multiple links between AP MLD601 and STA MLD602, such as... Figure 6 As shown, STA MLD602 can listen to the multicast service indication information sent by AP601-2 via STA602-2, and thus determine whether AP601-1 and AP601-3 have multicast services, as described above. Figure 4 In the multicast service transmission method 100 shown, each STA in STA MLD602 needs to listen for the TIM beacon frame sent by AP MLD601 on its own link in order to know whether AP MLD601 will send multicast service after the DTIM beacon frame. This greatly saves the power consumption of STA MLD602.

[0202] As can be seen, in this embodiment of the application, the first AP of the AP MLD can generate and send multicast service indication information. This multicast service indication information can indicate whether an AP in the AP MLD has multicast service. This AP can be the first AP or other APs in the AP MLD besides the first AP. This allows a STA in the STA MLD to know whether its associated AP has multicast service, or whether other APs in the AP MLD have multicast service. Compared to the method where each STA in the STA MLD can only listen to whether its associated AP has multicast service, this embodiment of the application improves the flexibility of AP MLD in notifying multicast services.

[0203] In this embodiment, the first AP of the AP MLD can generate and send multicast service indication information. This multicast service indication information can indicate whether each AP or some APs in the AP MLD have multicast services, thus allowing a single station in the STA MLD to know whether multiple APs have multicast services. Compared to the method in the STA MLD where each STA can only listen to whether its associated AP has multicast services, this embodiment helps to reduce the power consumption of the STA MLD.

[0204] In this embodiment of the application, one or more APs in the AP MLD can send multicast service indication information, and one or more STAs in the STAMLD can listen for multicast service indication information. The following describes the optional implementation methods.

[0205] Scenario 1: The AP sending multicast service indication information and the STA listening for multicast service indication information.

[0206] In one optional implementation, each AP in the AP MLD sends multicast service indication information, and any STA in the STA MLD can listen to the multicast service indication information on one of the links, or any multiple STAs in the STA MLD can listen to the multicast service indication information on their respective working links. For example, in Figure 3(c), AP601-1 and AP601-3 can also execute steps S201 and S202 respectively to send multicast service indication information, and any one or more STAs in the STA MLD 602 ​​can listen to the multicast service indication information on the corresponding link. The AP corresponding to each bit in the multicast indication information sent by each AP is fixed. If multiple STAs in the STA MLD 602 ​​listen to the multicast service indication information on the corresponding link, then these multiple STAs can be all or some of the STAs in the STA MLD. It can be seen that this implementation greatly improves the flexibility of the STA MLD in listening to multicast service indication information. Furthermore, allowing one or some STAs in the STA MLD to listen to multicast service indication information can also reduce the power consumption of the STA MLD to a certain extent.

[0207] In another optional implementation, the first STA in steps S203 and S204 can be a station operating on the main link in the STA MLD, and the first STA in the STA MLD listens to the multicast service indication information sent by the AP operating on the main link.

[0208] In another optional implementation, the first STA in steps S203 and S204 is a station operating on the main link in the STA MLD. Optionally, the STA MLD can inform the AP MLD of its own operating main link. For example, a station in the STA MLD located on the main link informs its corresponding AP in the AP MLD of its link identifier. In this way, the AP operating on the main link in the AP MLD sends multicast service indication information, while other APs do not need to send it. This helps save the power consumption of the AP MLD or allows the AP MLD to send multicast service indication information more effectively, such as by repeatedly sending it on multiple links.

[0209] The following describes the implementation method by which the AP MLD learns about the main link where the STA MLD is working.

[0210] In one implementation, the AP MLD can obtain the identification information of the main link determined by the STA MLD. For example, the identification information of the main link may include one or more of the following: the operation class and channel number corresponding to the main link; or, the MAC address (or BSSID) of the main link; or, the identifier (ID) of the main link. This application embodiment does not limit the specific content of the main link identification information; any information that can uniquely identify a station operating on the main link can be considered the main link identification information described in this application embodiment. The MAC address of the main link can be the MAC address of the STA operating on the main link, or the MAC address of the AP operating on the main link. When the MAC address of the main link is the MAC address of the AP operating on the main link, the MAC address of the main link can also be called the BSSID.

[0211] In one implementation, when the AP MLD and STA MLD are not associated, the AP MLD obtaining the identification information of the primary link may include: the AP MLD receiving an association request frame from the STA MLD. The link from which the AP MLD receives the association request frame is the primary link determined by the STA MLD, or the association request frame received by the AP MLD carries the link identification information of the primary link determined by the STA MLD. That is, the AP MLD can determine the station on the link where the association request frame is received (or the station that sent the association request frame) as the link identifier of the primary link; or, the AP MLD obtains the link identification information of the primary link carried in the association request frame.

[0212] In another implementation, when the AP MLD and STA MLD are already associated, the AP MLD obtains the link identification information of the primary link. This can include the AP MLD receiving a message frame from the STA MLD, which carries the link identification information of the primary link determined by the STA MLD. This message frame can be a management frame, a data frame, or a control frame, etc.

[0213] Understandably, in this implementation, the message frame is used to inform the AP MLD of the primary link after the STA MLD has been replaced; that is, the primary link identification information carried in the message frame is the link identification information of the replaced primary link. Optionally, the management frame may also include a replacement count to indicate the countdown to the primary link replacement.

[0214] Optionally, the AP MLD can also select a link as the primary link, and the link identifier of the primary link is used to indicate that the AP is operating on the primary link. The AP needs to send the link identifier of the primary link to its associated site or surrounding sites. In step S201, if the first AP is the AP operating on the primary link, then the multicast service indication information sent by the first AP can be used to indicate whether the first AP operating on the primary link has multicast services; or the multicast service indication information can be used to indicate whether the AP operating on the secondary link has multicast services; or the multicast service indication information can be used to indicate whether the first AP operating on the primary link has multicast services, and whether the AP operating on the secondary link has multicast services. Here, the secondary link is a link operated by other APs besides the first AP in the AP MLD, or the secondary link includes links other than the primary link among multiple links.

[0215] In this embodiment, the multicast service indication information sent by the first AP can be part or all of the bits of the multicast service indication information generated by the first AP. Specifically, sending only part of the bits of the multicast service indication information generated by the first AP helps to save signaling overhead. This embodiment is described below.

[0216] In this implementation, each bit of the multicast service indication information corresponds to a specific AP in the AP MLD. If the APs corresponding to the bits before the N1th bit of the multicast service indication information do not have multicast services, and the APs corresponding to the bits after the N2th bit also do not have multicast services, then the multicast service indication information sent by the first AP may only include bits N1 to N2. Here, N1 can be greater than or equal to 0 and less than the total number of bits in the generated multicast service indication information, and N2 can be greater than N1 and less than or equal to the total number of bits in the generated multicast service indication information. This implementation method is beneficial for saving signaling overhead. Furthermore, in this case, the multicast service indication information also includes an offset and a length field. The offset is used to indicate N1, and the length is used to indicate N2-N1+1 of the multicast service information.

[0217] For ease of explanation, the multicast service indication information generated by the first AP will be referred to as the first multicast service indication information, and the multicast service indication information sent by the first AP will be referred to as the second multicast service indication information. The second multicast service indication information may be the same as the first multicast service indication information, or the second multicast service indication information may be a subset of the bits of the first multicast service indication information.

[0218] If the second multicast service indication information consists of only a portion of the bits in the first multicast service indication information, the first AP also needs to send an offset and a length. This offset and length are used in the STA MLD to determine which APs correspond to the bits in the second multicast service indication information. The offset of the second multicast service indication information relative to the first multicast service indication information is simply referred to as the offset of the second multicast service indication information. If the second multicast service indication information consists of all the bits in the first multicast service indication information, the first AP may or may not send the offset and length.

[0219] The first multicast service indication information includes bits corresponding to each AP in the AP MLD. Furthermore, the correspondence between each bit of the first multicast service indication information and each AP in the AP MLD can be notified through the aforementioned management frame, or predefined based on the size of the link identifier operated by each AP. That is, the total number of bits in the first multicast service indication information can be equal to the total number of APs in the AP MLD. Optionally, the AP MLD can determine the one-to-one correspondence between each bit of the first multicast service indication information and each AP based on the size of the link identifier operated by each AP in the AP MLD.

[0220] The following discussion covers two cases, namely Case 2.1 and Case 2.2, where the second multicast service indication information is a subset of the first multicast service indication information.

[0221] Case 2.1: The second multicast service indication information starts from byte N1 of the first multicast service indication information and ends at byte N2. All bits of N1 are greater than or equal to 0 and N2 is greater than or equal to N1.

[0222] If the AP corresponding to all bits from bit 0 to bit N1*8-1 of the first multicast service indication information does not have multicast service, and the AP corresponding to bit (N2+1)*8 and all bits thereafter does not have multicast service, then the second multicast service indication information sent by the first AP can be all bits starting from byte N1 and ending at byte N2 of the first multicast service indication information.

[0223] In this scenario, the length of the second multicast service indication information sent by the first AP is N2-N1+1; the offset of the second multicast service indication information is N1. Therefore, when the station managed by the first AP in the STA MLD receives this length and offset, it can determine that the received second multicast service indication information is used to indicate whether the APs corresponding to bits N1*8 to ((N2+1)*8-1) have multicast services, and whether the APs corresponding to all bits from bit 0 to bit N1*8-1 do not have multicast services, and whether the APs corresponding to bit (N2+1)*8 and all bits thereafter do not have multicast services.

[0224] For example, suppose the first multicast service indication information is three bytes long, where each bit in byte 0 corresponds to an AP that does not have multicast service, and each bit in byte 2 corresponds to an AP that does not have multicast service. Then, the second multicast service indication information can consist of only the bits of byte 1. Therefore, the length of the second multicast service indication information is one byte, and the offset is one byte. Thus, after receiving the second multicast service indication information along with its length and offset, the first STA can determine that each bit in the second multicast service indication information indicates whether the APs corresponding to bits 8 to 15 have multicast service, and that the APs corresponding to each bit in byte 0 and byte 2 do not have multicast service.

[0225] In another implementation, in order to reduce the signaling overhead required to transmit the offset, i.e., to reduce the number of bits required to indicate the offset, the offset of the second multicast service indication information can be set to N1 / 2, where N1 is required to be an even number of bytes.

[0226] For example, if the offset sent by the first AP is 0 and the length is 1 byte, then the second multicast service indication information sent by the first AP includes bits 0 to 7 from the first multicast service indication information. Thus, the first STA can determine whether the APs corresponding to bits 0 to 7 have multicast services based on the values ​​of bits 0 to 7. If the offset sent by the first AP is 1 and the length is 1 byte, then the second multicast service indication information sent by the first AP includes byte 2 from the first multicast service indication information, i.e., bits 16 to 22. Thus, the first STA can determine whether the APs corresponding to bits 16 to 22 have multicast services based on the values ​​of bits 16 to 22.

[0227] For example, if the offset sent by the first AP is 0, the length is 1 byte, and the second multicast service indication information is 01100110, and bits 0 to 7 correspond to AP1 to AP8 in the AP MLD respectively, then the first STA can know that AP1, AP4, AP5, and AP8 do not have multicast services, while AP2, AP3, AP6, and AP7 do. Optionally, if bit 0 is predefined to have no meaning, i.e., it does not correspond to any AP, then bits 1 to 7 correspond to AP1 to AP7 in the AP MLD respectively, and the first STA can know that AP1, AP2, AP5, and AP6 have multicast services, while AP3, AP4, and AP7 do not.

[0228] As can be seen, in Scenario 1, the correspondence between each AP in the AP MLD and each bit in the first multicast service indication information is determined through predefined or management frame notification. This, in turn, facilitates the fact that the second multicast service indication information consists of only a portion of the bits in the first multicast service indication information, thus saving signaling overhead.

[0229] Case 2.2: The second multicast service indication information is the bits that start from byte 0 of the first multicast service indication information and end at byte N0-1, and the bits that start from byte N1 of the first multicast service indication information and end at byte N2.

[0230] In this scenario, the APs corresponding to bits N0*8-1 to N1*8-1 of the first multicast service indication information do not have multicast services, and the APs corresponding to bits N2*8 and the bits thereafter also do not have multicast services. Therefore, the second multicast service indication information sent by the first AP consists of the bits starting from byte 0 of the first multicast service indication information and ending at byte N0-1, and the bits starting from byte N1 of the first multicast service indication information and ending at byte N2.

[0231] Correspondingly, the length of the second multicast service indication information sent by the first AP is N0+N2-N1+1, and the offset of the second multicast service indication information is N1-N0. Then, when the station managed by the first AP in the STA MLD receives this length and offset, it can determine that the received second multicast service indication information is used to indicate whether the APs corresponding to bits 0 to (N0-1)*8-1 and bits N1*8+1 to N2*8-1 have multicast services, while the APs corresponding to bits (N0-1)*8 to (N1-1)*8 do not have multicast services.

[0232] In one implementation, to save the number of bits required for the offset, the offset of the second multicast service indication information sent by the first AP is half of the actual offset. Therefore, in this case, the offset sent by the first AP is (N1-N0) / 2, and the length is N0+N2-N1+1 bytes. Furthermore, since the offset is (N1-N0) / 2, it is required that: if N0 is odd, then N1 is also odd; if N0 is even, then N1 is also even.

[0233] Example 2

[0234] Figure 7 A flowchart illustrating a multicast service transmission method 400 applicable to multiple links is shown. In this multicast service transmission method 400, the multicast service indication information is a portion of the bits in the virtual bitmap field of the service indication bitmap (TIM) element. That is, the multicast service indication information is... Figure 2 The image shows a portion of the bits in a virtual bitmap field. For example... Figure 7 As shown, the multicast service transmission method 400 applicable to multiple links includes, but is not limited to, the following steps:

[0235] S401, AP MLD's first AP generates multicast service indication information;

[0236] S402, The first AP sends a TIM element;

[0237] The TIM element can be carried in beacon frames or other management frames, such as TIM frames. A portion of the virtual bitmap field in the TIM element includes the multicast service indication information; that is, the multicast service indication information is a subset of bits in the virtual bitmap field of the service indication bitmap TIM element.

[0238] Additionally, as described in Embodiment 1, optionally, for beacon frames, multicast service indication information may be carried only in DTIM beacon frames. Alternatively, multicast service indication information may be carried in other frames such as management frames, data frames, or control frames.

[0239] For example, Figure 8 It shows Figure 2 Each bit of the middle part of the virtual bitmap field, taking a 251-byte virtual bitmap field as an example, consists of 8 bits per byte. Figure 8 As shown, byte 0 includes bits 0 to 7, byte 1 includes bits 8 to 15, ..., and so on, and byte 250 includes bits 2000 to 2007.

[0240] In one implementation, the multicast service indication information is a portion of consecutive bits in the virtual bitmap field, such as the multicast service indication information being... Figure 8 Bits 1 to 7 in a portion of the virtual bitmap field can be used to indicate whether each AP in the AP MLD has multicast service.

[0241] In another embodiment, the multicast service indication information is a portion of non-contiguous bits in the virtual bitmap field, such as the multicast service indication information being... Figure 8 Bits 1, 2, and 4 in the partial virtual bitmap field can be used to indicate whether each AP in the AP MLD has multicast service.

[0242] S403, the first STA of the STA MLD receives the TIM element;

[0243] S404. The first STA reads the multicast service indication information from the virtual bitmap field of the TIM element and determines whether one or more APs in the AP MLD have multicast services.

[0244] For a detailed explanation of step S401, please refer to the above. Figure 5 The explanation of step S201 in the multicast service transmission method 200 shown will not be detailed here.

[0245] Optionally, the multi-link multicast service transmission method 400 further includes: for an AP that is determined to have multicast service, the STA in the STAMLD operating on the link of the AP receives the multicast service after the DTIM beacon frame.

[0246] In one example, multicast service indication information can be carried in any beacon frame, including TIM beacon frames and DTIM beacon frames. In this case, the aforementioned DTIM beacon frame is either the DTIM beacon frame following the TIM beacon frame, or it is the DTIM beacon frame carrying the multicast service indication information.

[0247] Another example is that the multicast service indication information is carried only in the DTIM beacon frame of the beacon frame. In this case, the DTIM beacon frame is the DTIM beacon frame carrying the multicast service indication information.

[0248] Optionally, the multicast service indication information may also be carried in other frames such as management frames, data frames, or control frames.

[0249] Specifically, for how to operate other APs in AP MLD and other STAs in STA MLD, please refer to the description in the embodiment section, which will not be detailed here.

[0250] As mentioned above Figure 2 As explained, the partial virtual bitmap is a subset of bits in the service indication virtual bitmap field, with each bit corresponding to an AID. Therefore, in this embodiment, the AP MLD assigns AIDs to each AP it includes, and then uses the bits corresponding to these AIDs in the partial virtual bitmap field to indicate whether the AP with that AID has multicast service; that is, the multicast service indication information is the bits corresponding to these AIDs. The AID assigned to an AP cannot be used by any AP in the AP MLD to assign to its associated site.

[0251] As can be seen, the multi-link multicast service transmission method 400 carries multicast service indication information through a portion of the virtual bit map field in the beacon frame, which can improve the flexibility of multicast service notification. Furthermore, when the multicast service indication information indicates whether multiple APs have multicast services, it can also reduce the power consumption of the STA MLD.

[0252] Assuming the communication system 300 shown in Figure 3(c), the AIDs of AP601-1 to AP601-3 in AP MLD601 are AID1, AID2, and AID3, respectively. These AID1, AID2, and AID3 correspond to three bits of a portion of the virtual bitmap field in the TIM beacon frame. For example... Figure 9 The multicast service transmission method 500 applicable to multiple links shown involves AP601-2 sending beacon frame 2, in which a portion of the virtual bitmap field carries multicast service indication information. STA602-1 listens to this beacon frame 2 on link 2. Reading the three bits corresponding to AID1, AID2, and AID3 from the portion of the virtual bitmap field of beacon frame 2, which is 111, STA602-1 can determine that AP601-1 to AP601-3 all have multicast services after the corresponding DTIM beacon frames. Therefore, STA602-1 to STA602-3 can each listen for subsequent multicast services on their respective operating links. This implementation avoids STA602-1 and STA602-3 periodically listening to beacon frames in STA MLD602 to determine if the corresponding AP has multicast services, thus saving power consumption in STA MLD602.

[0253] Optionally, if the multicast service indication information is only carried in the DTIM beacon frame, then the STA602-1 that receives the DTIM beacon frame can receive multicast services after the DTIM beacon frame; while other STAs of STA MLD602 still need to receive the DTIM beacon frames on their respective links, as well as the subsequent multicast services.

[0254] The following discussion covers two methods for AID configuration. Method 1 describes how the AP MLD explicitly assigns AIDs to each of its included APs, using association identifier configuration information. Method 2 describes how the AP MLD implicitly assigns AIDs to each of its included APs, where the AID corresponding to the first bit of a subset of consecutive bits in the virtual bitmap field corresponding to the multicast service indication information is predefined. This method can be further divided into two cases: Case 3.1 describes how to predefine the AIDs corresponding to APs when the APs in the AP MLD are not operating in multi-BSSID (Basic Service Set Identifier) ​​mode; Case 3.2 describes how to assign AIDs to each AP in the AP MLD when one or more APs in the AP MLD are operating in multi-BSSID mode. In this case, the virtual bitmap field of the TIM element also needs to assign AIDs to multiple APs in the multi-basic service set identifier set. Therefore, the AIDs assigned to each AP in the AP MLD cannot be the same as the AIDs assigned to multiple APs in the multi-basic service set identifier set. In other words, the bits corresponding to each AP in the virtual bitmap field of the AP MLD do not overlap with the bits corresponding to multiple non-transmission APs in the multi-basic service set identifier set.

[0255] Method 1: AP MLD explicitly assigns AIDs to each AP it includes.

[0256] Optionally, the AID configuration method includes, but is not limited to, the following steps: The first AP in the AP MLD generates association identifier configuration information, which indicates the association identifier corresponding to each AP in the AP MLD. Specifically, the association identifier configuration information includes one or more association identifier sub-configuration information, wherein the association identifier sub-configuration information for an AP includes the AP's AID and the AP's AID. Optionally, the association sub-configuration information can be carried in a sub-element or field storing single AP information in an MLD element used for information on multiple APs in the MLD; the first AP sends the association identifier configuration information. Each bit of the multicast service indication information is used to indicate whether the AP with the corresponding AID has multicast service; each AP's AID corresponds to each bit of the multicast service indication information.

[0257] The first AP that generates and sends the associated identification configuration information and the first AP that generates and sends the multicast service indication information in step S201 can be the same AP in the AP MLD, or they can be different APs in the AP MLD.

[0258] In one implementation, when the AP MLD and STA MLD are not associated, the association identification configuration information can be carried in the association response frame sent by the STA MLD. In another implementation, when the AP MLD and STA MLD are associated, the association identification configuration information can be carried in the management frame sent by the STA MLD.

[0259] In this implementation, since the AP MLD assigns AIDs to each AP, the multicast service indication information can be a portion of bits in a partial virtual bitmap, which can be continuous or non-continuous.

[0260] Furthermore, since some bits in the virtual bitmap field correspond to AIDs that are assigned to stations, and these bits are used to indicate whether the corresponding station has unicast services, in this embodiment, the association identifier assigned to each AP in the AP MLD is different from the association identifier assigned to the station associated with each AP. That is, the association identifier assigned to each AP in the AP MLD cannot be reassigned by each AP to the station it manages. However, the AIDs assigned by different APs to the stations they manage are relatively independent, that is, the AIDs assigned by different APs to the stations they manage can be repeated. For example, assuming the communication system 300 shown in Figure 3(c), the AIDs assigned to AP601-1 to AP601-3 in AP MLD601 are AID1, AID2, and AID3, respectively, then AID1, AID2, and AID3 cannot be reassigned to the stations associated with AP601-1 to AP601-3, such as STA in STA MLD602, STA in STA MLD603, and STA604. However, the AID assigned by AP601-1 to STA602-1 in STA MLD602 can be the same as the AID assigned by AP601-2 to STA602-2 in STA MLD602. Since STA602-1 and STA602-2 operate on different links (link 1 and link 2 respectively), the two will not be confused due to their identical AIDs.

[0261] Optionally, since the STAs in the STA MLD reside in different Basic Service Sets (BSS), the AP MLD can assign an AID to each STA MLD, meaning that all STAs in the STA MLD share a single AID without confusion. Alternatively, the AP MLD can assign an AID to each STA in the STA MLD, meaning that each STA in the STA MLD has its own unique AID.

[0262] As can be seen, this implementation method, by assigning AIDs to each AP in the AP MLD, utilizes a portion of the virtual bitmap field in the TIM element to inform the STA MLD whether each AP in the AP MLD has multicast services. Compared to the method in the multicast service processing method 100 described above, which uses bits 0 in the bitmap control field of the TIM beacon frame on each link to inform the APs on their respective links whether they have multicast services, this implementation method can improve the flexibility of multicast service notification. Furthermore, when the multicast service indication information indicates whether multiple APs have multicast services, it can also reduce the power consumption of the STA MLD.

[0263] For example, assuming the communication system 300 shown in Figure 3(c), the AIDs assigned to AP601-1 to AP601-3 in AP MLD601 are AID1, AID2, and AID3, respectively. AID1, AID2, and AID3 correspond to three bits of the virtual bitmap field in the TIM element.

[0264] Optionally, multiple AIDs assigned to multiple APs in the AP MLD can be consecutive;

[0265] Optionally, some virtual bitmap fields may not carry the multicast service indication information of the AP (called the reporting AP) that sent the virtual bitmap field, but may carry the multicast service indication information of other APs in the MLD where the reporting AP is located. The multicast service indication information of the reporting AP is still indicated by bit 0 in the bitmap control field.

[0266] There are two implementation methods for the "not carrying" part of the virtual bitmap field. One is that the virtual bitmap field carries the bit corresponding to the reporting AP, but this bit is reserved and has no meaning. The other is that the virtual bitmap field does not carry the bit corresponding to the reporting AP, which is applicable to other embodiments of the present invention and will not be described further.

[0267] Method 2: AP MLD implicitly assigns AIDs to each AP it includes.

[0268] When an AP MLD implicitly assigns AIDs to its constituent APs, it needs to consider whether any APs in the AP MLD are operating in a Multiple Basic Service Set Identifier (MPS) mode, and whether any APs operating in that MPS mode are transport APs. Therefore, Method 2 discusses two cases: Case 3.1 discusses how to assign AIDs to the constituent APs when no APs in the AP MLD are operating in MPS mode; Case 3.2 discusses how one or more APs in the AP MLD are operating in MPS mode, and at least one AP is a transport AP in the MPS mode.

[0269] To facilitate understanding, we will first explain the relevant concepts of Basic Service Set Identifier (BSSID).

[0270] In one implementation, the Multiple Basic Service Set Identifier (BSSID) set can be understood as a collection of cooperating Access Points (APs). All cooperating APs use the same operation set, channel number, and antenna interface. Within this multiple BSSID set, only one AP has a transmitted BSSID, while the others are non-transmitted BSSID APs. The information of the multiple BSSID set (i.e., the multiple BSSID elements) is carried in beacon frames, probe response frames, or neighbor reports sent by APs with transmitted BSSIDs. The BSSID information of an AP with a nontransmitted BSSID is derived by the site through the aforementioned beacon frames, probe response frames, or the Multiple BSSID element in neighbor reports. Specifically, the BSSID of an AP with a nontransmitted BSSID is calculated by combining the BSSID of the AP transmitting the BSSID with the BSSID Index field in the Multiple BSSID-Index element of its Nontransmitted BSSID profile. For details, please refer to the Draft 802.11REVmd_D3.0 protocol.

[0271] In another implementation, the multiple BSSID set can be understood as consisting of multiple APs. Each AP manages one BSS, and different APs can have different SSIDs and permissions, such as security mechanisms or transmission opportunities.

[0272] In the multiple BSSID set, only the AP with the BSSID "Transmitted BSSID" can send beacon frames and probe response frames. Therefore, if the probe request frame sent by the STA is to an AP with the BSSID "Nontransmitted BSSID" in the multiple BSSID set, then the AP with the BSSID "Transmitted BSSID" in the multiple BSSID set needs to help respond by sending a probe response frame.

[0273] In a set of multiple APs with multiple BSSIDs, one AP's BSSID is configured as a Transmitted BSSID, and the AP with the Transmitted BSSID can be called a Transmitted AP; the BSSIDs of the other APs are configured as Nontransmitted BSSIDs, and the APs with the Nontransmitted BSSIDs can be called Nontransmitted APs.

[0274] Among them, the frame format of multiple BSSID elements is as follows: Figure 10 As shown, a multi-BSSID element includes an element ID field, a length field, a maximum BSSID indicator field, and optional sub-element fields. The maximum BSSID indicator field indicates the maximum number n of BSSIDs contained in the multi-BSSID set. The optional sub-element fields include information about the BSSIDs of APs with non-transmitted BSSIDs.

[0275] The maximum number of APs allowed in a multi-BSSID set is 2^(N) n ), N n yes Figure 7 The value indicated by the MaxBSSID Indicator field in the multi-BSSID element shown is used to indicate the value. Therefore, bits 1 to 2^(N) of the service indicator virtual bitmap field can be used. n )-1 are respectively assigned to the APs with non-transport BSSIDs in this multi-BSSID set to indicate NonTxBSS IDs (identifiers) from 1 to 2. nDoes the AP with a nontransmitted BSSID of -1 have multicast service? The value of NonTxBSSID is equal to the value of the BSSID Index field in the Multiple BSSID-Index element of the nontransmitted BSSID profile within the Multiple BSSID element. The nontransmitted BSSID profile is an optional sub-element field.

[0276] Case 3.1: In the AP MLD, no AP is operating in the multi-basic service set identification mode.

[0277] In one implementation, each bit of the multicast service indication information as described in section S201 above corresponds to each AP of APMLD, so the starting bit position of the multicast service indication information in the partial virtual bit map field of the TIM element can be determined in a predefined manner.

[0278] In other words, the AIDs of each AP in the AP MLD are assigned consecutively starting from AIDx, for example, based on the size of the link identifier that each AP is working on, from largest to smallest or smallest to largest. Here, AIDx is predefined. Alternatively, the first bit or starting bit of the virtual bitmap field in the TIM element for this multicast service indication information is predefined.

[0279] In this embodiment, some bits in the virtual bitmap field of the TIM element corresponding to the multicast service indication information are continuous, that is, some continuous bits in the virtual bitmap field of the TIM element corresponding to the multicast service indication information.

[0280] For example, the AP MLD implicitly assigns AIDs to its multiple APs, that is, it assigns a default consecutive AID to each AP in the AP MLD. For example, by default, it assigns consecutive AIDs to each AP in the AP MLD starting from AID 1. Assuming that the AP MLD has 3 APs: AP1, AP2 and AP3, then by default, AP1, AP2 and AP3 are assigned AID1, AID2 and AID3 respectively.

[0281] The default order of AID allocation follows the order of the link identifiers of each AP. Assuming that the link identifiers of AP1, AP2 and AP3 are link identifier 3, link identifier 2 and link identifier 1 respectively, then by default, AID3, AID2 and AID1 will be assigned to AP1, AP2 and AP3 respectively.

[0282] As can be seen, this implementation does not require informing the managed sites of the AID corresponding to each AP through the association response frame or management frame described in the above implementation. Instead, the site side knows the AID by default, which helps to save signaling overhead.

[0283] In addition, since non-transport APs in a multi-BSSID set cannot send beacon frames, this implementation also applies to one or more APs in an APMLD that are operating in multi-BSSID mode, but the one or more APs are non-transport APs, that is, no AP in the MLD is a transport AP in the multi-BSSID set.

[0284] Optionally, a portion of the virtual bitmap field may not carry the multicast service indication information of the AP sending that portion of the virtual bitmap field (referred to as the reporting AP), but may carry the multicast service indication information of other APs in the MLD where the reporting AP resides. The multicast service indication information of the reporting APs is still indicated by bit 0 in the bitmap control field. In this case, the bits corresponding to the multicast service indication information in the portion of the virtual bitmap field are still consecutive; only the multicast service indication information of the reporting AP is skipped. For example, AP1, AP2, and AP3 in the AP MLD are implicitly assigned to AID1, AID2, and AID3, respectively, or bits 1 to 3 in the corresponding service indication virtual bitmap field. If AP1 sends multicast service indication information, this information only includes the multicast service indications of AP2 and AP3, using bits 1 to 2 in the portion of the virtual bitmap field; if AP2 sends multicast service indication information, this information only includes the multicast service indications of AP1 and AP3, using bits 1 to 2 in the portion of the virtual bitmap field.

[0285] Case 3.2: One or more APs in the AP MLD are operating in multi-BSSID mode, and at least one other AP is a transport AP in the multi-BSSID set.

[0286] Assuming there are n APs in the AP MLD that transmit BSSIDs, and the value indicated by the MaxBSSID Indicator field of the multi-BSSID set to which the y-th AP with a transmitting BSSID belongs is Ny, then the bits corresponding to each AP in the AP MLD are configured or predefined from bit x of the service indicator virtual bit map field. Alternatively, assuming there are n APs in the AP MLD, or n APs belonging to multiple BSSID sets, where Ny is 0 for APs not operating in multi-BSSID mode, and Ny is 0 for APs operating in multi-BSSID mode but not transmitting BSSIDs; the Ny of an AP operating in multi-BSSID mode and transmitting BSSIDs is equal to the value indicated by the MaxBSSID Indicator field of its multi-BSSID set.

[0287] In one implementation, the multicast service indication information starts with bit x in the service indication virtual bitmap field, where x equals max{2^(N1), 2^(N2), ..., 2^(N... y ), …, 2^(N) n )}.

[0288] In other words, the AID corresponding to the first bit of a contiguous set of bits in the virtual bitmap field corresponding to the multicast service indication information is AIDx. Alternatively, the AIDs of each AP in the AP MLD are continuously allocated starting with AIDx. x equals max{2^(N1), 2^(N2), ..., 2^(N... y ), …, 2^(N) n Alternatively, the bits corresponding to each AP in the service indication virtual bit bit diagram of the AP MLD are configured or predefined starting from bit x. Where x equals max{2^(N1), 2^(N2), ..., 2^(N... y ), …, 2^(N) n )}.

[0289] For example, the AP MLD has two APs, AP1 and AP2. Both AP1 and AP2 operate in multiple BSSID mode and transmit BSSIDs. The maximum BSSID indicator field in the multiple BSSID element sent by AP1 is 3, while the maximum BSSID indicator field in the multiple BSSID element sent by AP2 is 2. Therefore, the maximum number of APs with non-transmitted BSSIDs in the multiple BSSID set supported by AP1 is 7, while the maximum number of APs with non-transmitted BSSIDs in the multiple BSSID set supported by AP2 is 3. Thus, the starting AID of the AID assigned by the AP MLD to AP1 and AP2 is AID8, or the starting bit in the service indication virtual bitmap field of AP1 and AP2 is bit 8.

[0290] Furthermore, this implementation also applies to situations where one or more APs in the AP MLD are operating in multi-BSSID mode. Optionally, a portion of the virtual bitmap field may not carry multicast service indication information of the AP sending that portion of the virtual bitmap field (referred to as the reporting AP), but may carry multicast service indication information of other APs in the MLD where the reporting AP resides. The multicast service indication information of the reporting APs is still indicated by bit 0 in the bitmap control field. In this case, the bits corresponding to the multicast service indication information in the portion of the virtual bitmap field are still consecutive; only the multicast service indication information of the reporting APs is skipped. In the example above, the starting bit of AP1 and AP2 in the service indication virtual bitmap field is bit 8, and AP1 and AP2 in the AP MLD correspond to bits 8 to 9 in the service indication virtual bitmap field. If AP1 sends a multicast service indication message, the multicast service indication message will only include AP2's multicast service indication, and bit 8 in the partial virtual bitmap field will be used; if AP2 sends a multicast service indication message, the multicast service indication message will only include AP1's multicast service indication, and bit 8 in the partial virtual bitmap field will be used.

[0291] Similarly, the multi-link multicast service transmission methods 400 and 500 can also be implemented as described in the multi-link multicast service transmission method 200, where one or more APs in the AP MLD send a beacon frame carrying multicast service indication information, and one or more STAs in the STA MLD listen to the beacon frame. The difference lies in that the multicast service indication information in the multi-link multicast service transmission methods 400 and 500 is carried in a portion of the virtual bitmap field within the TIM element. Accordingly, one or more APs in the AP MLD can send the beacon frame, and any number of STAs in the STA MLD can listen to the beacon frame. This implementation significantly improves the flexibility of the STA MLD in listening to multicast service indication information. Furthermore, allowing one or more STAs in the STA MLD to listen to the multicast service indication information can also reduce the power consumption of the STA MLD. Optionally, the multicast service indication information is only carried in the DTIM beacon frame.

[0292] In another implementation, the first STA in steps S203 and S204 can be a station operating on the main link in the STA MLD, and the first STA in the STA MLD listens for beacon frames sent by the AP operating on the main link.

[0293] In another implementation, the first STA in steps S203 and S204 is a station operating on the main link in the STA MLD. Optionally, the STA MLD can inform the AP MLD of its own operating main link. For example, a station in the STA MLD located on the main link informs its corresponding AP in the AP MLD of its link identifier. In this way, the AP operating on the main link in the AP MLD sends beacon frames, while other APs do not need to send them. This helps save the power consumption of the AP MLD or allows the AP MLD to send multicast service indication information more effectively, such as by repeatedly sending it on multiple links.

[0294] In addition, the implementation method of how AP MLD learns about the main link of STA MLD operation can be found in the above description, and will not be described in detail here.

[0295] Similarly, in the multi-link multicast service transmission method 400 and 500, the multicast service indication information sent by the first AP may include bits corresponding to the AID of some APs, or bits corresponding to the AID of some sites, to save the bit overhead required by the TIM element. Assume the multicast service indication information is a partial virtual bitmap field in the TIM element, where the partial virtual bitmap field is a subset of bits of the service indication virtual bitmap field, and the AP service indication virtual bitmap field is neither sent nor carried in the TIM element. The following discusses the length field, offset, and partial virtual bitmap field (i.e., multicast service indication information) in the TIM element in two cases, namely cases 4.1 and 4.2.

[0296] Case 4.1: Case 3.1 applicable to both Method 1 and Method 2.

[0297] In other words, the relevant content in section 4.1 applies to situations where the APs in the AP MLD are not operating in multi-BSSID mode, or where some are operating in multi-BSSID mode but are non-transmission APs. Optionally, it can also apply to other situations.

[0298] The multicast service indication information consists of all bits starting with byte N1 and ending with byte N2 in the service indication virtual bit map field, where N1 is greater than or equal to 0 and N2 is greater than or equal to N1.

[0299] In this scenario, by employing the compression method in the protocol, when multiple APs with consecutive associated identifiers do not have multicast services, some virtual bitmap fields may omit the bits corresponding to these associated identifiers. This is achieved by using the offset in the TIM element to reduce the number of bits representing multicast service indication information in some virtual bitmap fields.

[0300] If the site corresponding to the AID whose bits before the largest even-numbered byte N1 and all bits after the smallest byte N2 in the Service Indication Virtual Bitmap field have not received downlink services or the AP corresponding to the AID has not sent multicast services, then the multicast service indication information is all bits starting from byte N1 and ending at byte N2 in the Service Indication Virtual Bitmap field.

[0301] To reduce the signaling overhead required to send the offset, i.e., to reduce the number of bits required to indicate the offset, the offset of the multicast service indication information can be set to N1 / 2, where N1 is an even-numbered byte number.

[0302] Therefore, the length field of the TIM element sent by the first AP is N2-N1+1+3, and the offset of the TIM element is (1 / 2)N1. Then, the station managed by the first AP in the STA MLD receives this length and offset, and determines that the multicast service indication information is used to indicate that the station corresponding to the AID from bit N1*8 to bit ((N2+1)*8-1) has not received downlink service or the AP corresponding to the AID has not sent multicast service. It determines that the AP corresponding to the AID of all bits from bit 0 to bit N1*8-1 has no multicast service, and the AP corresponding to the AID of bit (N2+1)*8 and all bits thereafter has no multicast service.

[0303] For example, if the offset in the TIM element sent by the first AP is 0 and the length field is 4 bytes (i.e., the partial virtual bitmap is 1 byte), then the multicast service indication information sent by the first AP is bits 0 to 7 in the partial virtual bitmap field. Thus, if the AP's AID is within the range of AIDs corresponding to bits 16 to 23, the first STA can determine whether the AP with the corresponding AID in bits 0 to 7 has multicast service based on the values ​​of bits 0 to 7. If the AP's AID is not within the range of AIDs corresponding to bits 0 to 7, then that AP does not send multicast service to its associated site or surrounding sites.

[0304] For example, if the first AP sends an offset of 1 and a length of 4 bytes (i.e., the partial virtual bitmap is 1 byte), then the multicast service indication information sent by the first AP is byte 2 of the partial virtual bitmap field, i.e., bits 16 to 23. Thus, if the AP's AID is within the range of AIDs corresponding to bits 16 to 23, the first STA can determine whether the AP with the corresponding AID in bits 16 to 23 has multicast service based on the values ​​of bits 16 to 23. If the AP's AID is not within the range of AIDs corresponding to bits 16 to 23, then that AP does not send multicast service to its associated site or surrounding sites.

[0305] For example, if the offset sent by the first AP is 0, the length is 4 bytes, part of the virtual bitmap field is 01100110, and bits 0 to 7 correspond to AP1 to AP8 in the AP MLD, then the first STA can know that AP1, AP4, AP5, and AP8 do not have multicast services, while AP2, AP3, AP6, and AP7 do. Optionally, if bit 0 is predefined to have no meaning, i.e., it does not correspond to any AP, then bits 1 to 7 correspond to AP1 to AP7 in the AP MLD, and the first STA can know that AP1, AP2, AP5, and AP6 have multicast services, while AP3, AP4, and AP7 do not.

[0306] Case 4.2: Applicable to Case 3.2 in Method 2 above.

[0307] In other words, the relevant content of scenario 4.2 applies to situations where one or more APs in the AP MLD are operating in multi-BSSID mode and one AP is a transmission AP. Optionally, it may also apply to other scenarios.

[0308] Method A: The multicast service indication information is located in a partial virtual bitmap field, which consists of bits starting at byte 0 and ending at byte N2 of the service indication virtual bitmap field. N2 is the smallest byte number such that all values ​​from bit (N2+1)*8 to bit 2007 in the service indication virtual bitmap field are 0. The largest byte number in the service indication virtual bitmap field is 251, corresponding to a maximum AID of 2^251-1 = 2007. At this point, the offset is 0, and the length field is N2+1+3.

[0309] Method B: The multicast service indication information is located in the partial virtual bitmap field, wherein the partial virtual bitmap field consists of the bits that start from byte 0 of the service indication virtual bitmap field and end at byte N0-1, and the bits that start from byte N1 of the service indication virtual bitmap field and end at byte N2.

[0310] The maximum number of bytes in the Service Indication Virtual Bitmap field is 251, corresponding to a maximum AID of AID2007. In this scenario, if the sites corresponding to AIDs N0*8-1 to N1*8-1 in the Service Indication Virtual Bitmap field do not receive downlink services or the APs corresponding to those AIDs do not send multicast services, and the sites corresponding to AIDs N2*8 to 2007 do not receive downlink services or the APs corresponding to those AIDs do not send multicast services, then the multicast service indication information sent by the first AP may include bits starting from byte 0 and ending at byte N0-1 in the Service Indication Virtual Bitmap field; and bits starting from byte N1 and ending at byte N2 in the Service Indication Virtual Bitmap field. Additionally, if N0 is odd, then N1 is also odd; if N0 is even, then N1 is also even.

[0311] In this case, the offset of the TIM element is (N1-N0) / 2, and the length field is N0+N2-N1+4 bytes. Additionally, since the offset is (N1-N0) / 2...

[0312] Additionally, if the AP MLD contains APs operating in multi-BSSID mode that transmit BSSIDs, and assuming that the maximum value of the MaxBSSID Indicator field for each AP operating in multi-BSSID mode and transmitting BSSIDs is n, then in this case, the minimum byte number of N0 must satisfy N0*8-2. n -N_AP<8, where N_AP is the number of APs included in the AP MLD or the number of APs minus 1. In this case, the offset is (N1-N0) / 2 bytes, and the length is N0+N2-N1+4 bytes.

[0313] In the embodiments provided above, the methods provided by the embodiments of this application have been described from the perspectives of AP MLD and STA MLD, respectively. To implement the functions of the methods provided in the embodiments of this application, AP MLD and STA MLD may include hardware structures and software modules, and may implement the above functions in the form of hardware structures, software modules, or a combination of hardware structures and software modules. One of the above functions can be executed in the form of hardware structures, software modules, or a combination of hardware structures and software modules. The following will combine... Figures 11 to 14 The communication device described in this application is described in detail. The communication device is an access point of an access point multi-link device or a site of a site multi-link device. Further, the communication device can be a device in an AP MLD; or, the communication device can be a device in a STA MLD.

[0314] Figure 11 A schematic block diagram of a communication device 100 is shown, which corresponds to any AP MLD or any AP of an AP MLD described in any of the above-described methods 200 to 500 for multicast service transmission over multiple links. Optionally, the communication device 100 is... Figures 3(a) to 3(c) AP MLD in the AP or the device therein;

[0315] The communication device 100 includes:

[0316] The processing unit 101 is used to generate multicast service indication information, which is used to indicate whether one or more APs of AP MLD have multicast services.

[0317] The communication unit 102 is used to send the multicast service indication information.

[0318] As can be seen, in the communication device 100, the multicast service indication information generated by the processing unit 101 can indicate whether it or other APs have multicast services, and then be sent by the communication unit 102 to the site multilink device. This allows any site in the site multilink device to listen to the multicast service indication information, improving the flexibility of multicast service notification. In addition, when the multicast service indication information indicates whether each or more APs in the AP MLD have multicast services, it allows any site in the site multilink device to know whether multiple APs have multicast services, avoiding the need for each site in the site multilink device to check whether there are multicast services on its own link, thereby saving power consumption of the site multilink device.

[0319] In one implementation, each bit of the multicast service indication information corresponds to each AP in the AP MLD; the value of each bit is used to indicate whether the AP corresponding to that bit has multicast service. This is specifically as described in the above method embodiment. Figures 5 to 6 The relevant content in the illustrated embodiments.

[0320] In addition, the multicast service indication information sent by the transceiver may be a portion of the multicast service indication information generated by the processor, as described in Cases 2.1 to 2.2, which will not be elaborated here.

[0321] In another implementation, the multicast service indication information is a portion of bits in the Partial Virtual Bit Map field of the Service Indication Bitmap (TIM) element. Alternatively, the multicast service indication information is a portion of consecutive bits in the Partial Virtual Bit Map field of the Service Indication Bitmap (TIM) element.

[0322] As can be seen, in this implementation, the AP MLD assigns an AID to each of its included APs, and then uses the bits corresponding to these AIDs in a partial virtual bitmap to indicate whether the AP with the AID has multicast service; that is, the multicast service indication information is the bits corresponding to these AIDs. See the above method embodiment section for details. Figures 7 to 9 The relevant content is shown below.

[0323] In addition, whether the AID corresponding to each AP in the AP MLD is explicitly assigned or implicitly predefined, or when it is necessary to consider how to determine the AID corresponding to each AP in the AP MLD when the AP MLD is working in multi-BSSID mode and is transmitting BSSID, please refer to Method 1 and Method 2 in the above method embodiment section, which will not be described in detail here.

[0324] For example, if the AID corresponding to each AP in the AP MLD is explicitly assigned, then in this communication device, the processing unit 101 is further used to generate association identifier configuration information, which is used to indicate the association identifier AID corresponding to each AP in the AP MLD; the AID of each AP corresponds to each bit of the multicast service indication information; the communication unit 102 is further used to send the association identifier configuration information.

[0325] In addition, in this embodiment, since the AID corresponding to some bits in some virtual bitmap fields is the AID of the site, the associated identifier AID corresponding to each bit of the multicast service indication information is different from the AID of the site managed by each AP in the AP MLD.

[0326] For example, the AID corresponding to the first bit of a subset of consecutive bits in the subset of virtual bitmap fields corresponding to the multicast service indication information is predefined.

[0327] For example, the AID corresponding to the first bit of a portion of consecutive bits in the virtual bit map field of the service indication bitmap TIM element corresponding to the multicast service indication information is AIDx;

[0328] The x is equal to max{2^(N1), 2^(N2), ..., 2^(N... y ), …, 2^(N) n )}; where n is the number of APs in the AP MLD that transmit Basic Service Set Identifier (BSSID), N y It is an AP that transmits BSSID. y The value of the largest Basic Service Set Identifier (BSSID) indicator field in the Multiple BSSID element of the broadcast, wherein the AP transmitting the BSSID... y It is the y-th AP in the AP MLD that transmits the BSSID.

[0329] In the communication device 100, the communication unit 102 is also used to send a Service Indication Bitmap (DTIM) beacon frame and the multicast service following the DTIM beacon frame. Specifically, the communication unit 102 can perform this operation when the AP where the communication device 100 is located has multicast service.

[0330] It should be understood that the communication device 100 described in the embodiments of this application can correspondingly execute the multi-link multicast service transmission method 200 to the multi-link multicast service transmission method 500 in the embodiments of this application, and the above-mentioned operations or functions of each unit in the communication device 100 are respectively for implementing Figure 5 and Figure 7 For the sake of brevity, the corresponding processes of each method in the code will not be elaborated here.

[0331] Figure 12 A schematic block diagram of a communication device 200 is shown. The communication device 200 corresponds to any of the STA MLDs described in the above-described methods 200 to 500 for multicast service transmission over multiple links, or any STA of a STA MLD, or a STA of a STA MLD operating on the main link. Optionally, the communication device 200 is... Figure 1 The STA MLD shown here is a STA or a device therein; or the communication device 200 is Figures 3(a) to 3(c) STA MLD of STA or device therein;

[0332] The communication device 200 includes:

[0333] Communication unit 201 is used to receive multicast service indication information from AP MLD, wherein the multicast service indication information is used to indicate whether one or more APs of AP MLD have multicast services;

[0334] Processing unit 202 is used to determine whether one or more APs have multicast services based on the multicast service indication information.

[0335] As can be seen, in the communication device 200, the processing unit 202 can determine whether one or more APs have multicast services based on the multicast service indication information. That is, the communication device 200 can not only determine whether its associated APs have multicast services, but also whether other APs in the AP MLD have multicast services, thereby improving the flexibility of multicast service notification. Furthermore, the multicast service indication information indicates whether multiple APs or each AP in the AP MLD have multicast services; that is, any STA in the STA MLD where the communication device 200 is located can determine whether multiple APs or each AP in the AP MLD have multicast services, avoiding the need for each STA in the STA MLD to listen for multicast service status, thus saving power consumption in the STA MLD where the communication device 200 is located.

[0336] In one embodiment, the STA corresponding to the communication device 200 is a station of the STA MLD operating on the main link. In this way, the communication unit 201 receives multicast service indication information from the AP MLD, specifically: the communication unit 201 listens for multicast service indication information from one AP of the AP MLD on the main link. This embodiment helps other STAs of the STA MLD avoid periodically listening for this multicast service indication information, thereby saving power consumption of the STA MLD.

[0337] How the communication device 200 determines the main link can be found in the description of the above method embodiments, and will not be detailed here.

[0338] In one embodiment, the communication unit 201 is further configured to receive a Transmit Service Indication Bitmap (DTIM) beacon frame and subsequent multicast services. In this embodiment, the communication unit 201 can perform this operation when the processing unit 202 determines that its corresponding AP has multicast services.

[0339] In one implementation, each bit of the multicast service indication information corresponds to each AP in the AP MLD; the value of each bit is used to indicate whether the AP corresponding to that bit has multicast service. This is specifically as described in the above method embodiment. Figures 5 to 6 The relevant content in the illustrated embodiments.

[0340] In addition, the multicast service indication information sent by the transceiver may be a portion of the multicast service indication information generated by the processor, as described in Cases 2.1 to 2.2, which will not be elaborated here.

[0341] In another implementation, the multicast service indication information is a portion of bits in the Partial Virtual Bit Map field of the Service Indication Bitmap (TIM) element. Alternatively, the multicast service indication information is a portion of consecutive bits in the Partial Virtual Bit Map field of the Service Indication Bitmap (TIM) element.

[0342] As can be seen, in this implementation, the AP MLD assigns an AID to each of its included APs, and then uses the bits corresponding to these AIDs in a partial virtual bitmap to indicate whether the AP with the AID has multicast service; that is, the multicast service indication information is the bits corresponding to these AIDs. See the above method embodiment section for details. Figures 7 to 9 The relevant content is shown below.

[0343] In addition, whether the AID corresponding to each AP in the AP MLD is explicitly assigned or implicitly predefined, or when it is necessary to consider how to determine the AID corresponding to each AP in the AP MLD when the AP MLD is working in multi-BSSID mode and is transmitting BSSID, please refer to Method 1 and Method 2 in the above method embodiment section, which will not be described in detail here.

[0344] For example, if the AID corresponding to each AP in the AP MLD is explicitly assigned, then in the communication device 200, the communication unit 201 is further configured to receive association identifier configuration information, which is used to indicate the association identifier AID corresponding to each AP in the AP MLD; the AID of each AP corresponds to each bit of the multicast service indication information; the processing unit 202 is further configured to determine the AID corresponding to each AP in the AP MLD according to the association identifier configuration information.

[0345] In addition, in this embodiment, since the AID corresponding to some bits in some virtual bitmap fields is the AID of the site, the associated identifier AID corresponding to each bit of the multicast service indication information is different from the AID of the site managed by each AP in the AP MLD.

[0346] For example, the AID corresponding to the first bit of a subset of consecutive bits in the subset of virtual bitmap fields corresponding to the multicast service indication information is predefined.

[0347] For example, the AID corresponding to the first bit of a portion of consecutive bits in the virtual bit map field of the service indication bitmap TIM element corresponding to the multicast service indication information is AIDx;

[0348] The x is equal to max{2^(N1), 2^(N2), ..., 2^(N... y ), …, 2^(N) n )}; where n is the number of APs transmitting BSSID in the AP MLD, N y It is an AP that transmits BSSID. y The value of the Maximum Basic Service Set Identifier (BSSID) field in the Multiple BSSID element broadcast, and the AP of the transmitted BSSID. y It is the y-th AP in the AP MLD that transmits the BSSID.

[0349] It should be understood that the communication device 200 described in the embodiments of this application can correspondingly execute the multi-link multicast service transmission method 200 to the multi-link multicast service transmission method 500 in the embodiments of this application, and the above-mentioned operations or functions of each unit in the communication device 200 are respectively for implementing Figure 5 and Figure 7 For the sake of brevity, the corresponding processes of one STA or the first STA in the STA MLD in each method are not described in detail here.

[0350] Figure 13A schematic block diagram of a communication device 300 is shown. In one implementation, the communication device 300 corresponds to any of the methods described in the multicast service transmission methods 200 to 500 applicable to multiple links, specifically the AP MLD, or any AP of the AP MLD. Optionally, the communication device 300 may be... Figure 1 The AP MLD in the AP or the device therein; or the communication device 300 is Figures 3(a) to 3(c) The AP in the AP MLD or a device therein. Optionally, the communication device 300 is a chip, chip system, or processor, etc., that implements the above method embodiments. The communication device 300 can be used to implement the methods described in the above method embodiments, and for details, please refer to the description in the above method embodiments.

[0351] In another implementation, the communication device 300 corresponds to any of the STA MLDs described in the above-mentioned methods 200 to 500 for multicast service transmission applicable to multiple links, or any STA of the STA MLD, or a STA of the STA MLD operating on the main link. Optionally, the communication device 300 may be... Figure 1 The STA of the STA MLD or the device therein; or the communication device 300 is Figures 3(a) to 3(c) The STA in the STA MLD or a device therein. Optionally, the communication device 300 is a chip, chip system, or processor, etc., that implements the above method embodiments. The communication device 300 can be used to implement the methods described in the above method embodiments, and for details, please refer to the description in the above method embodiments.

[0352] The communication device 300 may include one or more processors 301. The processor 301 may be a general-purpose processor or a dedicated processor, such as a baseband processor or a central processing unit (CPU). The baseband processor can be used to process communication protocols and communication data, while the CPU can be used to control the communication device (e.g., base station, baseband chip, terminal, terminal chip, DU or CU, etc.), execute computer programs, and process data from the computer programs.

[0353] The communication device 300 may further include a transceiver 305. The transceiver 305, also known as a transceiver unit, transceiver, or transceiver circuit, is used to implement transmission and reception functions. The transceiver 305 may include a receiver and a transmitter. The receiver, also known as a receiver circuit, is used to implement a receiving function; the transmitter, also known as a transmitter or transmitting circuit, is used to implement a transmitting function. Optionally, the communication device 300 may further include an antenna 306.

[0354] Optionally, the communication device 300 may include one or more memories 302, which may store instructions 304, which may be computer programs that can be executed on the communication device 300 to cause the communication device 300 to perform the methods described in the above method embodiments. Optionally, the memories 302 may also store data. The communication device 300 and the memories 302 may be provided separately or integrated together.

[0355] For the communication device 300 used to implement the AP MLD in the multi-link multicast service transmission method 200 to multi-link multicast service transmission method 500 in the above method embodiments:

[0356] Processor 301 can be used to execute Figure 5 Step S201 in the process; Figure 7 Step S401; Optional implementation of the AID corresponding to the AP in Method 1 and Method 2 above, such as generating associated identifier configuration applicable to multicast service transmission method information for multiple links.

[0357] Transceiver 305 is used to perform Figure 5 Step S202 in the process; Figure 7 Step S402; Optional implementation of the AID corresponding to AP in Method 1 and Method 2 above, such as sending associated identifier configuration information.

[0358] For the communication device 300 used to implement the STA function of the STA MLD in the multi-link multicast service transmission method 200 to multi-link multicast service transmission method 500 in the above method embodiments:

[0359] Transceiver 305 is used to perform Figure 5 Step S203 in the process; Figure 7 Step S403; Optional implementation of the AID corresponding to the AP in Method 1 and Method 2 above, such as receiving associated identifier configuration information.

[0360] Processor 301 can be used to execute Figure 5 Step S204 in the process; Figure 7 Step S404; an optional implementation of determining the AID of AP in Method 1 and Method 2 above, such as determining the association identifier of each AP of AP MLD based on the association identifier configuration information.

[0361] In one implementation, the processor 301 may include a transceiver for implementing receiving and transmitting functions. For example, the transceiver may be a transceiver circuit, an interface, or an interface circuit. The transceiver circuit, interface, or interface circuit for implementing receiving and transmitting functions may be separate or integrated. The aforementioned transceiver circuit, interface, or interface circuit can be used for reading and writing code / data, or it can be used for transmitting or relaying signals.

[0362] In one implementation, processor 301 may store instructions 303, which may be a computer program. The computer program 303 runs on processor 301 and causes communication device 300 to perform the methods described in the above method embodiments. The computer program 303 may be embedded in processor 301; in this case, processor 301 may be implemented in hardware.

[0363] In one implementation, the communication device 300 may include circuitry capable of performing the functions of transmitting, receiving, or communicating as described in the foregoing method embodiments. The processor and transceiver described in this application can be implemented on integrated circuits (ICs), analog ICs, radio frequency integrated circuits (RFICs), mixed-signal ICs, application-specific integrated circuits (ASICs), printed circuit boards (PCBs), electronic devices, etc. The processor and transceiver can also be manufactured using various IC process technologies, such as complementary metal-oxide-semiconductor (CMOS), n-metal-oxide-semiconductor (NMOS), positive-channel metal-oxide-semiconductor (PMOS), bipolar junction transistors (BJTs), bipolar CMOS (BiCMOS), silicon-germanium (SiGe), gallium arsenide (GaAs), etc.

[0364] The communication device described in the above embodiments may be an AP MLD or an AP of an AP MLD, but the scope of the communication device described in this application is not limited to this, and the structure of the communication device may vary. Figure 13 The communication device may be a standalone device or part of a larger device. For example, the communication device may be:

[0365] (1) Independent integrated circuit IC, or chip, or chip system or subsystem;

[0366] (2) A collection of one or more ICs, optionally including storage components for storing data and computer programs;

[0367] (3) ASIC, such as modem;

[0368] (4) Modules that can be embedded in other devices;

[0369] (5) Receivers, terminals, smart terminals, cellular phones, wireless devices, handheld devices, mobile units, vehicle-mounted devices, network devices, cloud devices, artificial intelligence devices, etc.

[0370] (6) Others, etc.

[0371] For cases where the communication device can be a chip or a chip system, please refer to [link / reference]. Figure 14 The diagram shows the structure of the chip. The chip shown in Figure 14 includes a processor 401 and an interface 402. There can be one or more processors 401, and multiple interfaces 402.

[0372] For the function of the AP MLD in the chip used to implement the multi-link multicast service transmission method 200 to 500 in the above method embodiments:

[0373] In one implementation,

[0374] Processor 401 is used to generate multicast service indication information, which is used to indicate whether one or more APs of AP MLD have multicast services;

[0375] Interface 402 is used to send the multicast service indication information.

[0376] As can be seen, in this chip, the multicast service indication information generated by the processor can indicate whether it or other APs have multicast services, and then be sent by the transceiver to the site multilink device. This allows any site in the site multilink device to listen for the multicast service indication information, improving the flexibility of multicast service notification. Furthermore, when this multicast service indication information indicates whether each or more APs in the AP MLD have multicast services, it allows any site in the site multilink device to know whether multiple APs have multicast services, avoiding the need for each site in the site multilink device to check for multicast services on its own link, thus saving power consumption of the site multilink device.

[0377] Optionally, the chip can also perform the AP function of AP MLD in multi-link multicast service transmission method 200 to multi-link multicast service transmission method 500, which will not be described in detail here.

[0378] The chip is used to implement the STA function of the STA MLD in the multi-link multicast service transmission method 200 to multi-link multicast service transmission method 500 in the above method embodiments.

[0379] In one implementation, interface 402 is used to receive multicast service indication information from AP MLD, wherein the multicast service indication information is used to indicate whether one or more APs of AP MLD have multicast services.

[0380] Optionally, the processor 401 is configured to determine whether the one or more APs have multicast services based on the multicast service indication information.

[0381] As can be seen, in this chip, the processor can determine whether one or more APs are providing multicast services based on multicast service indication information. In other words, this chip can not only determine whether its associated APs are providing multicast services, but also whether other APs in the AP MLD are providing multicast services, thus improving the flexibility of multicast service notification. Furthermore, the multicast service indication information indicates whether multiple APs or each AP in the AP MLD are providing multicast services. This means that any STA in the STA MLD where the chip is located can determine whether multiple APs or each AP in the AP MLD are providing multicast services, avoiding the need for each STA in the STA MLD to listen for multicast service information, thus saving power consumption in the STA MLD where the chip is located.

[0382] Optionally, the chip can also perform the STA function of STA MLD in multi-link multicast service transmission method 200 to multi-link multicast service transmission method 500, which will not be described in detail here.

[0383] Those skilled in the art will also understand that the various illustrative logical blocks and steps listed in the embodiments of this application can be implemented by electronic hardware, computer software, or a combination of both. Whether such functionality is implemented through hardware or software depends on the specific application and the overall system design requirements. Those skilled in the art can implement the described functionality using various methods for each specific application, but such implementation should not be construed as exceeding the scope of protection of the embodiments of this application.

[0384] This application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a computer, implements the functions of any of the above method embodiments.

[0385] This application also provides a computer program product that, when executed by a computer, implements the functions of any of the above method embodiments.

[0386] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented, in whole or in part, as a computer program product. The computer program product includes one or more computer programs. When the computer program is loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer program can be stored in a computer-readable storage medium or transferred from one computer-readable storage medium to another. For example, the computer program can be transferred from one website, computer, server, or data center to another via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium accessible to a computer or a data storage device such as a server or data center that integrates one or more available media. The available media may be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., high-density digital video discs (DVDs)), or semiconductor media (e.g., solid-state disks (SSDs)).

[0387] Those skilled in the art will understand that the various numerical designations such as "first," "second," etc., involved in this application are merely for the convenience of description and are not intended to limit the scope of the embodiments of this application, nor do they indicate the order of sequence.

[0388] At least one in this application can also be described as one or more, and multiple can be two, three, four or more, and this application does not impose any limitation. In the embodiments of this application, for a technical feature, the technical features in that technical feature are distinguished by "first", "second", "third", "A", "B", "C" and "D", and there is no order or size among the technical features described by "first", "second", "third", "A", "B", "C" and "D".

[0389] The correspondences shown in the tables of this application can be configured or predefined. The values ​​of the information in each table are merely examples and can be configured to other values; this application is not limited to these values. When configuring the correspondences between information and parameters, it is not necessarily required to configure all the correspondences shown in each table. For example, the correspondences shown in some rows of the tables in this application may not be configured. Furthermore, appropriate modifications and adjustments can be made based on the above tables, such as splitting, merging, etc. The names of the parameters shown in the headings of the above tables can also use other names that the communication device can understand, and the values ​​or representations of the parameters can also be other values ​​or representations that the communication device can understand. In the implementation of the above tables, other data structures can also be used, such as arrays, queues, containers, stacks, linear lists, pointers, linked lists, trees, graphs, structures, classes, heaps, hash tables, or hash tables, etc.

[0390] The term "predefined" in this application can be understood as definition, pre-defined, stored, pre-stored, pre-negotiated, pre-configured, solidified, or pre-burned.

[0391] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0392] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0393] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for multicast service transmission applicable to multiple links, characterized in that, The method includes: The first access point (AP) of the access point multilink device (AP MLD) generates multicast service indication information. The AP MLD and the site multilink device (STA MLD) have multiple associated links. The AP MLD includes multiple APs, where one AP corresponds to one of the associated links. The first AP is one of the multiple APs. The multicast service indication information indicates whether the multiple APs of the AP MLD have multicast services. The multicast service indication information includes a portion of bits from a partial virtual bitmap field in the service indication bitmap (TIM) element. The portion of bits in the partial virtual bitmap field are consecutive bits. The number of bits in the portion of the partial virtual bitmap field corresponding to the AP MLD is a fixed value. One or more bits in the portion of the partial virtual bitmap field corresponding to the AP MLD, excluding the bits corresponding to the APs of the AP MLD, are set to zero by default. The bits corresponding to the APs of the AP MLD do not include the bits corresponding to the first AP. The first AP sends the multicast service indication information.

2. The method according to claim 1, characterized in that, The multicast service indication information is used to indicate whether each AP of the AP MLD has multicast service.

3. The method according to claim 1 or 2, characterized in that, The associated identifier AID corresponding to each bit of the multicast service indication information is different from the AID of each site managed by each AP in the AP MLD.

4. A method for multicast service transmission suitable for multiple links, characterized in that, The method includes: A first STA of a Site Multilink Device (STA MLD) receives multicast service indication information from an Access Point MLD (AP MLD). The STA MLD comprises multiple STAs; multiple associated links exist between the STA MLD and the AP MLD; wherein one STA corresponds to one of the associated links; the multicast service indication information indicates whether multiple APs of the AP MLD have multicast services; the multicast service indication information includes a portion of bits from a partial virtual bitmap field in a Service Indication Bitmap (TIM) element, wherein the portion of bits in the partial virtual bitmap field are consecutive bits; the number of bits in the portion of the partial virtual bitmap field corresponding to the AP MLD is a fixed value; one or more bits in the portion of the partial virtual bitmap field corresponding to the AP MLD, except for the bits corresponding to the APs of the AP MLD, are set to zero by default; wherein the bits corresponding to the APs of the AP MLD do not include the bits corresponding to the first AP; the first AP is one of the multiple APs of the AP MLD. The first station (STA) determines whether multiple APs of the AP MLD have multicast services based on the multicast service indication information.

5. The method according to claim 4, characterized in that, The first station STA in the STA MLD is a station operating on the main link. The first site STA of the STA MLD receives multicast service indication information from the AP MLD, including: The first STA of the STA MLD listens for multicast service indication information from an AP of the AP MLD on the main link.

6. The method according to claim 4 or 5, characterized in that, The multicast service indication information is carried in the Transmit Service Indication Bitmap (DTIM) beacon frame.

7. The method according to claim 6, characterized in that, The method further includes: The first station (STA) receives the multicast service after receiving the DTIM beacon frame.

8. A first access point AP in an access point multi-link device (AP MLD), characterized in that, The AP MLD includes multiple access points (APs), and the AP MLD has multiple associated links with the site multi-link device (STA MLD); wherein, one of the multiple APs corresponds to one of the multiple associated links; the first AP is one of the multiple APs; the first access point AP of the access point multi-link device (AP MLD) includes a transceiver and a processor; The processor is configured to generate multicast service indication information, which indicates whether multiple APs of the AP MLD have multicast services. The multicast service indication information includes a portion of bits from a partial virtual bitmap field within a service indication bitmap (TIM) element. These partial virtual bitmap bits are consecutive bits. The number of bits in the partial virtual bitmap field corresponding to the AP MLD is a fixed value. One or more bits in the partial virtual bitmap field corresponding to the AP MLD, excluding the bits corresponding to the APs of the AP MLD, are set to zero by default. The bits corresponding to the APs of the AP MLD do not include the bits corresponding to the first AP. The transceiver is used to send the multicast service indication information.

9. The first access point AP of the access point multi-link device AP MLD according to claim 8, characterized in that, The multicast service indication information is used to indicate whether each AP of the AP MLD has multicast service.

10. The first access point AP of the access point multi-link device AP MLD according to claim 8 or 9, characterized in that, The associated identifier AID corresponding to each bit of the multicast service indication information is different from the AID of each site managed by each AP in the AP MLD.

11. A site STA of a Site Multilink Device (STA MLD), characterized in that, The STA MLD includes multiple STAs; the STA MLD has multiple associated links with the Access Point Multilink Device (AP MLD); the site is one of the sites in the site multilink device associated with the AP MLD, wherein one of the multiple STAs corresponds to one of the multiple associated links; the site STA of the site multilink device includes a transceiver; The transceiver is configured to receive multicast service indication information from the AP MLD, the multicast service indication information indicating whether multiple APs of the AP MLD have multicast services; the multicast service indication information includes a portion of bits in a partial virtual bitmap field of a service indication bitmap (TIM) element, the portion of bits in the partial virtual bitmap field being consecutive bits; the number of bits in the portion of bits in the partial virtual bitmap field corresponding to the AP MLD is a fixed value; one or more bits in the portion of bits in the partial virtual bitmap field corresponding to the AP MLD, except for the bits corresponding to the APs of the AP MLD, are set to zero by default; wherein, the bits corresponding to the APs of the AP MLD do not include the bits corresponding to the first AP; the first AP is one of the multiple APs of the AP MLD; The site STA of the site multi-link device STA MLD can determine whether multiple APs of the AP MLD have multicast services based on the multicast service indication information.

12. The site STA of the site multi-link device STA MLD according to claim 11, characterized in that, The site of the multi-link device operates on the main link. The transceiver receives multicast service indication information from the AP MLD, specifically: The transceiver is used to listen for multicast service indication information from an AP MLD on the main link.

13. The site STA of the Site Multi-Link Device (STA MLD) according to claim 11, characterized in that, The multicast service indication information is carried in the Transmit Service Indication Bitmap (DTIM) beacon frame.

14. The site STA of the site multi-link device STA MLD according to claim 13, characterized in that, The transceiver is also used to receive multicast services following the DTIM beacon frame.

15. A chip system, characterized in that, It includes at least one processor and an interface; the processor operates to cause a first access point in the access point multilink device to perform the method of any one of claims 1 to 3.

16. A chip system, characterized in that, It includes at least one processor and an interface; the processor operates to cause a site in a site multilink device to perform the method of any one of claims 4 to 7.

17. A computer-readable storage medium, characterized in that, Used to store a computer program that, when run on a computer, causes the computer to perform the method as described in any one of claims 1 to 3; or, to perform the method as described in any one of claims 4 to 7.

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