Low-latency service transmission method and system

Abstract

The embodiment of the present invention relates to the field of communications, and discloses a low-latency service transmission method and system, wherein the method includes: identifying whether the current service to be transmitted is a low-latency service; and giving priority to the identified low-latency service. The present application scheme can avoid conflicts and interferences between different types of services by pre-identifying whether the service to be transmitted is a low-latency service and distinguishing between low-latency services and non-low-latency services, thereby ensuring the stability of low-latency service transmission. If it is confirmed that the service to be transmitted is a low-latency service, the identified low-latency service is given priority, thereby ensuring the transmission quality and stability of the low-latency service.

Description

Technical Field

[0001] The present invention relates to the field of communications, and in particular to a low-delay service transmission method and system. Background Art

[0002] Wi-Fi standards have been committed to improving the peak rate and capacity of the network. However, in high-density scenarios such as airports, hotels, stadiums, and multi-residential apartments, previous Wi-Fi standards cannot guarantee stable network latency and low latency performance. Some emerging applications, such as telemedicine, virtual reality (VR), industrial control, logistics, and robotics, have strict requirements on network latency and require the network to be able to transmit large amounts of data in real time and with predictability. In addition, many IoT applications also require the network to support massive device access. For this type of low latency traffic, the network needs to be able to transmit data in a very short time to ensure the smoothness and real-time experience of the user. If the network latency is too high, users may encounter problems such as screen freezes, intermittent sound, and operation failures, which will affect the normal operation of the business.

[0003] In order to meet the needs of low-latency services, Wi-Fi protocols are constantly being improved and optimized to enhance network performance and flexibility. Among them, the next-generation Wi-Fi technology, Wi-Fi 8, takes ultra-high reliability (Ultra-High Reliability, UHR) of data transmission as its core goal. How to improve the reliability of low-latency service transmission by designing a UHR solution is an issue that needs to be addressed urgently. Summary of the invention

[0004] The purpose of the embodiments of the present invention is to provide a low-latency service transmission method and system, which can reduce the maximum value and fluctuation range of network transmission delay as much as possible, so as to achieve the effect of improving the transmission reliability of low-latency services.

[0005] In order to solve the above technical problems, an embodiment of the present invention provides a low-latency service transmission method, comprising:

[0006] Identify whether the service to be transmitted is a low-latency service;

[0007] And, prioritize the identified low-latency services.

[0008] An embodiment of the present invention further provides a low-delay service transmission system, comprising:

[0009] An access point AP and a station, wherein the access point AP and the station are used to jointly execute the low-delay service transmission method as described above.

[0010] Compared with the prior art, the embodiments of the present invention can avoid conflicts and interferences between different types of services by pre-identifying whether the service to be transmitted is a low-latency service based on the Enhanced Distributed Channel Access (EDCA) function of the existing WiFi system, and distinguishing between low-latency services and non-low-latency services, thereby ensuring the stability of low-latency service transmission. If the service to be transmitted is confirmed to be a low-latency service, the identified low-latency service is processed preferentially, thereby ensuring the transmission quality and stability of the low-latency service. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 The specific process of the low-delay data transmission method according to the embodiment of the present invention is as follows: Figure 1 ;

[0012] Figure 2 The specific process of the low-delay data transmission method according to the embodiment of the present invention is as follows: Figure 2 ;

[0013] Figure 3 is an EDCA parameter set element according to an embodiment of the present invention. Figure 1 ;

[0014] Figure 4 is a diagram of AC_LL Parameter Record fields according to an embodiment of the present invention;

[0015] Figure 5 is a mapping relationship diagram from ACI to AC according to an embodiment of the present invention;

[0016] Figure 6 is a diagram of a multi-user EDCA parameter set element according to an embodiment of the present invention;

[0017] Figure 7 The specific process of the low-delay data transmission method according to the embodiment of the present invention is as follows: Figure 3 ;

[0018] Figure 8 is an EDCA parameter set element according to an embodiment of the present invention. Figure 2 ;

[0019] Fig. 9 This is a schematic diagram of low-delay service transmission according to an embodiment of the present invention. Figure 1 ;

[0020] Fig.10 This is a schematic diagram of low-delay service transmission according to an embodiment of the present invention. Figure 2;

[0021] Fig.11 This is a schematic diagram of low-delay service transmission according to an embodiment of the present invention. Figure 3 ;

[0022] Fig.12 This is a schematic diagram of low-delay service transmission according to an embodiment of the present invention. Figure 4 ;

[0023] Fig.13 This is a schematic diagram of low-delay service transmission according to an embodiment of the present invention. Figure 5 ;

[0024] Fig.14 The preemption indication frame structure according to the embodiment of the present invention is Figure 1 ;

[0025] Fig.15 The preemption indication frame structure according to the embodiment of the present invention is Figure 2 ;

[0026] Fig.16 This is a schematic diagram of low-delay service transmission according to an embodiment of the present invention. Figure 5 ;

[0027] Fig.17 is the BSR control subfield format according to an embodiment of the present invention Figure 1 ;

[0028] Fig.18 is the BSR control subfield format according to an embodiment of the present invention Figure 2 ;

[0029] Fig.19 is the BSR control subfield format according to an embodiment of the present invention Figure 3 . DETAILED DESCRIPTION

[0030] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the following will be described in detail with reference to the accompanying drawings. However, it will be appreciated by those skilled in the art that in the various embodiments of the present invention, many technical details are provided in order to enable the reader to better understand the present application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical scheme claimed in the present application can be implemented.

[0031] In order to meet the needs of low-latency services and improve throughput, the WiFi protocol has introduced some new technologies and functions, such as OFDMA (Orthogonal Frequency Division Multiple Access), MU-MIMO (Multi-User Multiple Input Multiple Output), and multi-AP coordination. The R-TWT (Restricted-Target wake time) mechanism is also proposed in Wi-Fi7, which protects and prioritizes low-latency traffic by allocating R-TWT SP (Service Period) and overlapping quiet intervals. R-TWT enables the basic service combination BSS to use enhanced medium access protection and resource reservation to provide more reliable predictable delays for delay-sensitive services on wireless links.

[0032] The next generation of Wi-Fi technology, Wi-Fi 8, aims to provide ultra-high reliability (UHR: Ultra High Reliability) wireless communications. It is further developed on the basis of IEEE 802.11be (i.e. Wi-Fi 7) to meet the stringent requirements of emerging applications such as Industry 4.0, Industrial Internet of Things, autonomous driving, telemedicine, etc. These applications require the network to be able to transmit large amounts of data with extremely low latency and extremely high reliability to ensure security and efficiency. Therefore, improving the reliability of low-latency service transmission is an urgent problem to be solved. This application designs a UHR solution to reduce the tail and jitter of the delay distribution, reduce the maximum value and fluctuation range of the network transmission delay, so as to improve the reliability of low-latency traffic transmission.

[0033] One embodiment of the present invention relates to a low-delay service transmission method, such as Figure 1 As shown, the low-latency service transmission method provided in this embodiment includes the following steps.

[0034] Step 101: Identify whether the service currently to be transmitted is a low-latency service.

[0035] Specifically, in IT, latency is the time between a user request and the completion of the request, and low latency traffic refers to the ability of an optimized computer network to process large amounts of data messages with minimal delay. Many applications require low latency to help applications run faster and more smoothly, thereby improving user experience and increasing customer satisfaction. Based on the above characteristics of low latency, in order to ensure the immediacy and reliability of low-latency service transmission, it is possible to distinguish between low-latency services and non-low-latency services, and identify whether the current service to be transmitted is a low-latency service.

[0036] Step 102: Prioritize the identified low-latency services.

[0037] Specifically, the basic principle of Enhanced Distributed Channel Access (EDCA) is to classify and schedule data frames according to different Quality of Service (QoS) requirements, which are divided into four access categories / access categories (AC), namely voice service (AC_VO), video service (AC_VI), best effort (AC_BE) and background traffic (AC_BK).

[0038] Each AC has a corresponding queue for storing data frames of the corresponding type. Each AC also has a set of corresponding EDCA parameters for controlling the behavior of the AC when competing for channels. EDCA parameters include AIFS (arbitration frame interval), CWmin (minimum contention window), CWmax (maximum contention window), TXOP (transmission opportunity), etc. Taking voice and video as examples, they require shorter AIFS and smaller CWmin / CWmax during transmission to reduce waiting time and collision probability and improve transmission success rate. At the same time, they require longer TXOP to allow continuous transmission of multiple data frames to improve throughput and efficiency.

[0039] In other words, the setting of EDCA parameters can reflect the importance and characteristics of different types of services. After identifying that the service to be transmitted is a low-latency service, in order to ensure the stability of low-latency service transmission and avoid conflicts and interference between different types of services, the identified low-latency service can be prioritized. The priority treatment method can be designed by designing EDCA parameters that enable it to be transmitted first.

[0040] Compared with the related art, the present application, based on the EDCA of the existing WiFi system, can avoid conflicts and interferences between different types of services by pre-identifying whether the service to be transmitted is a low-latency service and distinguishing between low-latency services and non-low-latency services, thereby ensuring the stability of low-latency service transmission. If the service to be transmitted is confirmed to be a low-latency service, the identified low-latency service is processed preferentially, thereby ensuring the transmission quality and stability of the low-latency service.

[0041] Another embodiment of the present application relates to a low-latency service transmission method, such as Figure 2As shown, the low-latency service transmission method in this embodiment is a detailed description of the aforementioned embodiment, and the specific contents are as follows.

[0042] Step 201: Create an independent access category with the highest priority for the low-latency service in advance and set the EDCA parameters of the access category.

[0043] Specifically, based on the EDCA strategy in the current WiFi system, a new access category, or access category (AC), is designed for low-latency services. It can be named AC_LL (Low Latency), which is specifically used for the transmission of low-latency services. Since the existing EDCA has four types of ACs, namely, voice service (AC_VO), video service (AC_VI), best effort (AC_BE), and background traffic (AC_BK), an independent access category with the highest priority, AC_LL, can be created in advance for low-latency services, so that it has the highest priority, that is, the service priority of AC_LL is higher than that of AC_VO, AC_VI, AC_BE, and AC_BK.

[0044] At the same time, since the EDCA parameters of each AC include AIFS (arbitration frame interval), CWmin (minimum contention window), CWmax (maximum contention window), TXOP (transmission opportunity), etc. After creating an independent highest priority access category AC_LL for low-latency services, set the corresponding EDCA parameters for the access category AC_LL.

[0045] Step 202: Determine whether the service to be transmitted is a low-latency service according to the access category of the service to be transmitted.

[0046] Specifically, after creating an independent access category AC_LL for the low-latency service, it is possible to determine whether the service to be transmitted is a low-latency service according to the access category of the service to be transmitted. That is, it is determined whether the access category of the service to be transmitted is AC_LL. If so, it is determined that the service to be transmitted is a low-latency service; if not, it is determined that the service to be transmitted is not a low-latency service.

[0047] Step 203: Prioritize the identified low-delay services according to the EDCA parameters of their corresponding access categories.

[0048] Specifically, corresponding to the highest priority access type AC_LL of low-delay services, the EDCA parameters of AC_LL can be set as follows: AC_LL has the shortest AIFS (Arbitration Inter-Frame Spacing), that is, AIFS[AC_LL] = SIFS + AIFSN * Slot Time, where the AISFN of AC_LL should not be greater than the AISFN value of AC_VO, that is, AISFN ≤ 2, thereby reducing the waiting time before competing for the channel. AC_LL has the smallest contention window: CWmin (minimum contention window) and CWmax (maximum contention window), that is, CWmin[AC_LL] ≥ CWmin[AC_VO], CWmax[AC_LL] ≤ CWmax[AC_VO], thereby reducing the collision probability and backoff time when competing for the channel. Wherein, CWmin[AC_VO] = (aCWmin+1) / 4-1, CWmax[AC_VO] = (aCWmin+1) / 2-1. This application does not impose any specific restrictions on CWmin and CWmax, and they can be adjusted according to actual needs in the application. For example, when CWmin=15, CWmin[AC_VO]=3, CWmax[AC_VO]=7, then CWmin[AC_LL]≥3, CWmax[AC_LL]≤7, and the corresponding specific configuration can be: CWmin[AC_LL]=2, CWmax[AC_LL]=6. AC_LL has the longest TXOP (transmission opportunity), TXOP limit[AC_LL]≥TXOP limit[AC_VO], so that multiple data frames can be sent continuously to improve throughput and efficiency.

[0049] Accordingly, the configuration of the EDCA parameter set element also needs to be updated, and the fields corresponding to AC_LL need to be added, such as Figure 3 As shown in the figure, the AC_LL Parameter Record field has the same structure as other AC types, as shown in the figure. Figure 4 In addition, the mapping of ACI (AC Index) to AC also adds 1 bit to AC_LL, as shown in the following figure. Figure 5 Similarly, for multi-user EDCA parameter configuration, the AC_LL field should also be added synchronously, as shown in the following figure. Figure 6 As shown, the structure of MU AC_LLParameter Record is the same as that of other access types.

[0050] In one example, the low-latency service includes at least: a predictable low-latency service and an event-driven low-latency service.

[0051] At this time, the execution process corresponding to the above step 201 can be: setting access categories and EDCA parameters of access categories for predictable low-latency services and event-driven low-latency services respectively in advance; wherein the priority of the access category of the event-driven low-latency service is higher than the priority of the access category of the predictable low-latency service.

[0052] Specifically, low-latency services can be further subdivided into predictable low-latency services and event-driven low-latency services (also called bursty low-latency services) according to their characteristics and needs. In this case, in the AC_LL category, it can also be further divided into two subcategories, corresponding to predictable low-latency services and event-driven low-latency services, that is, access categories and EDCA parameters of access categories can be set in advance for predictable low-latency services and event-driven low-latency services.

[0053] For predictable low-latency services, since their transmission time and data volume are fixed or known, corresponding resources can be allocated and scheduled in advance. However, for event-driven low-latency services, since their transmission time and data volume are random or unknown, resources need to be allocated and scheduled with priority when they occur. Based on the characteristics of predictable low-latency services and event-driven low-latency services, the priority of the access category of event-driven low-latency services is set higher than that of the access category of predictable low-latency services.

[0054] Compared with the related art, the above embodiment of the present application creates an independent access category with the highest priority for low-latency services in advance and sets the EDCA parameters of the access category. When it is determined that the service to be transmitted is a low-latency service, the low-latency service is preferentially processed according to the EDCA parameters corresponding to the newly defined access category of the low-latency service. The low-latency service reduces the waiting time before competing for the channel through the shortest AIFS, reduces the collision probability and backoff time when competing for the channel through the smallest contention window, and allows multiple data frames to be sent continuously through the longest TXOP, thereby improving throughput and efficiency. That is, by creating the highest priority access category for low-latency services and setting the EDCA parameters of the access category, when the transmitted service is a low-latency service, it can be ensured that the low-latency service is processed preferentially, thereby improving the reliability of low-latency service transmission.

[0055] Another embodiment of the present application relates to a low-latency service transmission method, such as Figure 7 As shown, the low-latency service transmission method in this embodiment can serve as a supplementary implementation of the aforementioned implementation, and the specific contents are as follows.

[0056] Step 301: Map the identified access category of the low-latency service to the existing access category with the highest priority.

[0057] Specifically, on the basis that EDCA has four types of ACs, namely voice service (AC_VO), video service (AC_VI), best effort (AC_BE) and background traffic (AC_BK), since AC_VO has the highest priority among the above four ACs, low-latency services can be mapped to the highest priority access category AC_VO. In this way, no matter what the original priority of the low-latency service is, it will be uniformly mapped to AC_VO. Correspondingly, low-latency services will also use the EDCA parameters corresponding to AC_VO, including AIFS, CWmin, CWmax, TXOP limit, etc.

[0058] Step 302: Prioritize the identified low-latency services according to the mapped EDCA parameters of the access category.

[0059] Specifically, when the identified low-latency services are given priority according to the EDCA parameters of the mapped access category AC_VO, the low-latency services have the EDCA parameters of AC_VO, namely, a shorter AIFS and a smaller CWmin / CWmax to reduce waiting time and collision probability and improve transmission success rate; a longer TXOP to allow continuous transmission of multiple data frames to improve throughput and efficiency.

[0060] In one example, when the above step 301 is executed, that is, after the access category of the low-latency service is mapped to the existing access category with the highest priority, the low-latency service transmission method in this embodiment further includes:

[0061] Reconfigure the EDCA parameters of the mapped access category;

[0062] At this time, the above step 302: giving priority to the identified low-latency services according to the EDCA parameters of the mapped access category is specifically as follows:

[0063] The identified low-latency services are given priority according to the reconfigured EDCA parameters of the mapped access categories.

[0064] Specifically, after the AC of the low-latency service is mapped to AC_VO, more stringent EDCA parameters are also configured for the low-latency service mapped to AC_VO. The parameter values ​​can refer to the following method: AISFN≤2; CWmin[AC_VO]≥(aCWmin+1) / 4-1; CWmax[AC_VO]≤(aCWmin+1) / 2-1; and the TXOP limit is not less than the original TXOP limit of AC_VO. After the reconfiguration is completed, the identified low-latency service is prioritized according to the reconfigured EDCA parameters of the mapped access category.

[0065] In another example, the low-latency service includes at least: a predictable low-latency service and an event-driven low-latency service.

[0066] At this time, the execution steps for reconfiguring the EDCA parameters of the mapped access categories may be: after mapping the access categories of the predictable low-latency service and the event-driven low-latency service respectively, the EDCA parameters of the two mapped access categories are reconfigured differently so that the event-driven low-latency service has a higher priority than the access category of the predictable low-latency service.

[0067] Specifically, low-latency services can be further subdivided into predictable low-latency services and event-driven low-latency services (also referred to as bursty low-latency services) according to their characteristics and needs. For predictable low-latency services, since their transmission time and data volume are fixed or known, corresponding resources can be allocated and scheduled in advance. For event-driven low-latency services, since their transmission time and data volume are random or unknown, resources need to be allocated and scheduled immediately when they occur. Based on the characteristics of predictable low-latency services and event-driven low-latency services, after the access categories of predictable low-latency services and event-driven low-latency services are mapped separately, the EDCA parameters of the two mapped access categories can be reconfigured differently, and the priority of the access category of the event-driven low-latency service can be set higher than the priority of the access category of the predictable low-latency service.

[0068] In another example, the EDCA parameter includes a flag bit for indicating whether the current access category can be allocated with a low-delay service.

[0069] At this time, the specific execution process of step 301 may be:

[0070] The access category of the identified low-latency service is mapped to an existing access category whose identification bit indicates that the low-latency service can be allocated and has a higher priority.

[0071] Specifically, a higher access category refers to an access category with a higher priority than the access category originally corresponding to the low-latency service. The EDCA parameter contains a flag bit for indicating whether the current access category can be allocated with a low-latency service. The flag bit is a reserved bit in each AC parameter record in the existing EDCA parameter set element, which is used to indicate whether the current access type can be allocated with a low-latency service. Therefore, the reserved bit in each AC parameter record in the existing EDCA parameter set element can be reused, such as Figure 8 As shown in the figure, when Low Latency Indication is 1, it means that the current AC allows low-latency services with a lower priority than it to be mapped to the current AC category, which is divided into four access categories with priorities: AC_VO higher than AC_VI higher than AC_BE higher than AC_BK. Low-latency services are allocated to higher-priority ACs based on their own latency requirements, rather than being mapped based on the configured TID.

[0072] For example, if the TID of the current low-latency service corresponds to AC_BK, and the Low Latency Indication of AC_VI is 1 at this time, the STA can classify the data packets of the current low-latency service into the AC_VI category. If the Low Latency Indication of AC_VO is also 1 at this time, the STA can consider mapping to AC_VO or AC_VI according to the emergency situation of the current low-latency service. On the contrary, if the Low Latency Indication is 0, it means that the current AC category does not support cross-category low-latency service mapping.

[0073] In another example, step 102 may include the following steps:

[0074] Pre-set a time threshold and a data volume threshold for describing the tolerable delay of the low-latency service; map the access category of the identified low-latency service to the existing access category according to the relationship between the maximum time value and the maximum data volume value of the tolerable delay indicated in the configuration information of the low-latency service and the time threshold and the data volume threshold;

[0075] The smaller the time value is than the time threshold, and / or the larger the data volume value is than the data volume threshold, the higher the priority of the corresponding mapped existing access category is;

[0076] The identified low-latency services are processed preferentially according to the EDCA parameters of the mapped access category.

[0077] Specifically, when mapping the access category of the low-latency service, the mapping method on the STA side can be: judging whether to upgrade the mapped access category (AC) according to the urgency of the low-latency service and the data volume of the low-latency service. Two thresholds can be set. LatencyTh is used to judge the urgency of the low-latency service, that is, when the maximum tolerable delay configured by the low-latency service is less than LatencyTh, it means that the low-latency service is more urgent; set the second threshold LLPacketSizeTh. When the data volume of the low-latency service is greater than LLPacketSizeTh, it means that the data volume of the low-latency service is large and needs to be processed first.

[0078] Based on the two thresholds of LatencyTh and LLPacketSizeTh, the STA side can follow any one of the following three solutions when performing access category (AC) mapping for judging low-latency services.

[0079] Solution 1: When the maximum delay that a low-latency service can bear is less than LatencyTh, or the amount of low-latency service data is greater than LLPacketSizeTh, the access category (AC) mapped to the low-latency service can be upgraded. In this solution, if a low-latency service that meets one of the above two conditions should be mapped to AC_BK, and if the LowLatency Indication of AC_VI is 1, the mapped access category of the low-latency service can be raised to AC_VI.

[0080] Solution 2: When the maximum tolerable delay of the low-latency service is less than LatencyTh, and the amount of low-latency service data is greater than LLPacketSizeTh, the access category (AC) mapped to the low-latency service can be upgraded. In this solution, if the low-latency service that meets both of the above conditions should be mapped to AC_BK, and if the Low Latency Indication of AC_VI is 1, the mapped access category of the low-latency service can be raised to AC_VI.

[0081] Solution 3: When either the condition that the low-latency service can bear the maximum delay is less than LatencyTh or the condition that the low-latency service data volume is greater than LLPacketSizeTh is met, the access category (AC) mapped to the low-latency service can be upgraded by one level; when both conditions are met, the access category (AC) mapped to the low-latency service can be upgraded by two levels. For example, if a low-latency service that meets both conditions should be mapped to AC_BK, and if the LowLatency Indication of AC_VO is 1, the mapped access category (AC) of the low-latency service can be upgraded to AC_VO.

[0082] In addition, if the target mapping access category Low Latency Indication of the low-latency service is configured as 0, that is, cross-category low-latency service mapping is rejected, the low-latency service can try to map to the next higher priority access category, or stop cross-category mapping, that is, continue to map to the access category it should be mapped to.

[0083] Compared with the related technologies, this embodiment maps the access category of the identified low-latency service to the existing access category with the highest priority, and gives priority to the identified low-latency service according to the EDCA parameters of the mapped access category. It can provide the highest priority and optimal resource allocation for the low-latency service, ensure the transmission quality and stability of the low-latency service, and avoid the degradation of user experience and service interruption due to excessive network delay. At the same time, it can provide the low-latency service with a shorter waiting time and a smaller collision probability, reduce the number of retransmissions and retransmission delays of data frames, save transmission time and bandwidth resources, provide the low-latency service with longer transmission opportunities and greater throughput, and adapt to low-latency services of different types and scales.

[0084] Another embodiment of the present application relates to a low-latency service transmission method. The low-latency service transmission method in this embodiment is a supplement to the previous embodiment. This embodiment involves low-latency service transmission when low-latency services are generated on different devices. The specific contents are as follows.

[0085] When the low-latency service is a low-latency service sent by the TXOP holder, the low-latency service transmission method is as follows:

[0086] When the low-latency service is a low-latency service sent by the TXOP holder, the step of giving priority to the identified low-latency service may include:

[0087] After the TXOP holder completes the transmission of the non-low-latency service being transmitted, it immediately inserts the transmission of the low-latency service, and then receives the BA containing the feedback of the non-low-latency service replied by the receiving end of the non-low-latency service.

[0088] Specifically, when a TXOP holder (which can be an AP or a non-AP STA) is transmitting data and a low-latency service data packet arrives and needs to be sent immediately, the TXOP holder immediately inserts the transmission of the low-latency service after completing the transmission of the non-low-latency service being transmitted, and then receives the BA (Block ACK) containing feedback of the non-low-latency service replied by the receiving end of the non-low-latency service.

[0089] In one example, when the non-low-latency service and the low-latency service are sent to the same receiving end, the BA replied by the receiving end and received by the TXOP holder also includes feedback of the low-latency service.

[0090] Specifically, if low-latency services and non-low-latency services are sent to the same receiver, the transmitter should include the low-latency services when sending Block Ack Request (BAR). Correspondingly, the receiver's BA should also include the feedback of the low-latency services, that is, the low-latency services and non-low-latency services only need to reply with one BA. Fig. 9 As shown in the figure, while the AP (Access Point) is transmitting a non-low-latency data packet to STA1 (Station), it receives a data packet for low-latency services to STA1. At this time, after the transmission of the non-low-latency data packet is completed, the low-latency data packet is inserted and sent together. Correspondingly, STA1 combines the reception results of the non-low-latency data packet and the low-latency data packet in the same BA and feeds them back to the AP.

[0091] In another example, when the non-low-latency service and the low-latency service are sent to two different receiving ends, the TXOP holder transmits the non-low-latency service being transmitted, and then further includes:

[0092] The TXOP holder requests the receiving end of the non-low-latency service to suspend the feedback of BA. After the low-latency service transmission is completed and the BA fed back by the receiving end of the low-latency service is obtained, the TXOP holder sends a BAR to the receiving end of the non-low-latency service in order to obtain the BA fed back by the receiving end.

[0093] Specifically, Fig.10 As shown, if the AP has a low-latency data packet to send to another STA, STA1 suspends BA feedback. After the low-latency service transmission is completed, the AP sends a BAR to STA1 to request BA feedback.

[0094] In another example, when the low-latency service is a low-latency service sent by the TXOP holder, the identified low-latency service is preferentially processed, including:

[0095] After receiving the data packet of the low-latency service, the TXOP holder immediately interrupts the currently transmitted non-low-latency service and starts transmitting the low-latency service. After the transmission is completed, according to the delay requirement of the interrupted non-low-latency service, if there is no timeout, the interrupted non-low-latency service will continue to be transmitted. If there is a timeout, the interrupted non-low-latency service will be retransmitted.

[0096] When the low-latency service is a low-latency service sent by the TXOP responder, that is, when the TXOP responder (which can be an AP or a non-AP STA) receives a data packet sent by the TXOP holder and encounters a burst of low-latency service data packets that need to be sent immediately, the TXOP responder needs to complete the reception and reply of the data packet within the channel resources granted by the TXOP holder, while also considering the transmission of the low-latency service data packet. At this time, the low-latency service transmission method is as follows:

[0097] In one example, when the low-latency service is a low-latency service sent by a TXOP responder, and the TXOP responder is an access point AP and the TXOP holder is a station other than the access point AP, the identified low-latency service is preferentially processed, including:

[0098] The AP sends a first preemption indication to the site to instruct the site to interrupt the non-low-latency service that the AP is transmitting; the site sends confirmation information of the first preemption indication to the AP; after receiving the confirmation information of the first preemption indication, the AP starts to transmit the low-latency service to the receiving end.

[0099] Specifically, when the TXOP responder is an AP, such as Fig.11 As shown, at this time, the AP is receiving data from the TXOP holder STA1, and the AP has a low-latency service data packet to transmit to STA1. Since STA1 owns the current TXOP, the AP cannot send a data packet directly, but needs to first notify STA1 that it has a low-latency service that needs to be transmitted first. Therefore, the AP needs to send a preemption indication (PreEmptInd) to STA1, informing STA1 that it has a low-latency service that needs to preempt the current TXOP, and requires STA1 to interrupt its current transmission. STA1 receives PreEmptInd and replies with an acknowledgment message (ACK) to the AP. The purpose of the preemption indication is mainly to notify the device that has a low-latency service to transmit that it can transmit the low-latency service. After receiving the preemption indication, the low-latency service can be transmitted after a SIFS (Short Inter-Frame Space) duration. Similarly, if the target of the AP's low-latency service data packet is another STA (station), such as STA2, the content and sending method of the preemption indication are the same as the above process, and this application will not repeat them here. The preemption indication PreEmptInd can be sent as a separate control frame or management frame (such as Action Frame), or it can be attached to other control frames (such as CTS) or management frames. This application does not impose specific restrictions on the sending form of the preemption request (PreEmptReq) and the preemption indication (PreEmptInd).

[0100] In another example, when the low-latency service is a low-latency service sent by a TXOP responder, and the TXOP responder is a station other than an access point AP, and the TXOP holder is an access point AP, the identified low-latency service is preferentially processed, including:

[0101] The station sends a first preemption request to the AP to request the AP to agree that the station preempts the current TXOP;

[0102] If the AP agrees that the station preempts the current TXOP, the AP will interrupt the transmission of non-low-latency services between the AP and the station and send a second preemption indication to the station. After receiving the second preemption indication, the station starts to send low-latency services to the AP.

[0103] If the AP does not agree that the station preempts the current TXOP, the AP ignores the first preemption request and continues to transmit non-low-latency traffic between the station and the AP.

[0104] Specifically, when the TXOP responder is a non-AP STA, STA1 has a low-latency service data packet to transmit to the AP, but the TXOP holder is the AP. Fig.12 As shown, STA1 needs to send a preemption request (PreEmptReq) to AP, requesting AP to agree to preempt the current TXOP. After receiving PreEmptReq, AP can decide whether to agree to preempt according to its own strategy. If the preemption is agreed, AP needs to send a preemption indication PreEmptInd to the requesting STA1, and notify the current TXOP holder to interrupt the transmission. If the preemption is not agreed, AP ignores PreEmptReq and continues the current transmission. PreEmptReq can be sent as a separate control frame or management frame (such as Action Frame), or it can be attached to other control frames (such as RTS) or management frames. The PreEmptInd fed back by AP can be sent as a separate control frame or management frame (such as Action Frame), or it can be attached to other control frames (such as CTS) or management frames. This application does not impose specific restrictions on the sending form of the preemption request (PreEmptReq) and the preemption indication (PreEmptInd).

[0105] In another example, when the low-latency service is a low-latency service sent by a third-party site that is not a TXOP holder and a TXOP responder, the identified low-latency service is prioritized, including:

[0106] The third-party station sends a second preemption request to the AP in the TXOP to request the AP to agree that the third-party station preempts the current TXOP;

[0107] If the AP agrees that the third-party station preempts the current TXOP, the AP will interrupt the transmission of non-low-latency services between the stations in the TXOP and send a second preemption indication to the third-party station. After receiving the second preemption indication, the third-party station starts to send low-latency services to the AP.

[0108] If the AP does not agree that the third-party station preempts the current TXOP, the AP ignores the second preemption request and continues to transmit non-low-latency traffic with the stations in the TXOP.

[0109] Specifically, when the low-latency service comes from a third-party station (STA), that is, the low-latency service is neither the TXOP holder nor the TXOP responder's transmission data, such as Fig.13 As shown. AP is transmitting data to STA1. At this time, STA2 has a low-latency service data packet to transmit to AP. STA2 needs to send a preemption request (PreEmptReq) to AP, requesting AP to agree to preempt the current TXOP. After receiving PreEmptReq, AP can decide whether to agree to preempt according to its own strategy. If the preemption is agreed, AP needs to send a preemption consent feedback PreEmptInd to the requesting STA2. If the preemption is not agreed, AP ignores PreEmptReq and continues the current transmission. PreEmptReq can be sent as a separate control frame or management frame (such as Action Frame), or it can be attached to other control frames (such as RTS) or management frames. The PreEmptInd fed back by AP can be sent as a separate control frame or management frame (such as Action Frame), or it can be attached to other control frames (such as CTS) or management frames. This application does not impose specific restrictions on the sending form of the preemption request (PreEmptReq) and the preemption indication (PreEmptInd).

[0110] Accordingly, the design of the preemption request (PreEmptReq) and the preemption indication (PreEmptInd) may be specifically performed with reference to the following settings.

[0111] When the preemption indication frame is sent as an independent frame to a device that has low-latency services to transmit and implement preemption, the preemption indication frame structure can refer to Fig.14 The Frame Control field is used to identify the frame type and subtype, as well as other control bits. There are two options for the frame type and subtype:

[0112] Solution 1: Use the preemption indication frame as a control frame (such as CTS), then the frame type field should be configured as 01 and the subtype should be configured as 0000.

[0113] Solution 2: Use the preemption indication frame as a management frame (such as Action Frame). The frame type field should be configured as 00 and the subtype field should be configured as 0111.

[0114] Accordingly, the Duration field is used to specify the duration of the low-latency service data packet in microseconds; the RA field is used to specify the MAC address of the receiving device; the TA field is used to specify the MAC address of the sending device; and the Control Info field is used to carry other control information, such as delay requirement information, OMI (Operation mode Indication) information, and SM (Spatial Multiplexing) power save parameters. The Control Info field is optional and is configured according to the needs of the low-latency service. Among them, the delay requirement of the low-latency service is the latest acceptable sending time for the low-latency service. If it is necessary to switch the working mode, the OMI information can be included in the Control Info field to indicate the target working mode and other parameters. If it is necessary to update the relevant parameters of SM power save, the SM power save element can be included in the Control Info field to indicate the sleep and wake-up cycles between the AP and the STA.

[0115] When the preemption indication frame is used as a feedback frame for a preemption request, the TA field can be omitted to save bandwidth and reduce latency. In this case, the frame format can be as follows: Fig.15 As shown. When the TXOP holder has a frame to transmit to the device that needs to be preempted, the preemption indication can be attached to the existing frame for transmission to reduce additional overhead. For example, if the TXOP holder has a control frame such as RTS or BAR to transmit at this time, the preemption indication can be attached to the control frame for transmission together, without the need to send a separate preemption indication frame.

[0116] The main purpose of the preemption request is to inform the TXOP holder or AP that it has a low-latency service to transmit, and inform the data volume of the low-latency service, as well as the recommended working mode, SM Power save and other parameter configurations. If the TXOP holder or AP agrees to preempt the transmission of the low-latency service, it will send PreEmptInd to indicate that it agrees to the preemption operation and give the corresponding parameter configuration.

[0117] Similar to the preemption indication PreEmptInd, the preemption request PreEmptReq also has two forms. One is sent as an independent frame. The format of the preemption request frame is the same as Fig.14Similar, the difference lies in the configuration of the Frame Control field. In the frame format of the preemption request PreEmptReq, the Frame Control field is used to identify the frame type and subtype, as well as other control bits. There are two options for the frame type and subtype:

[0118] Solution 1: Use the preemption request frame as a control frame (such as RTS). The frame type field should be configured as 01 and the subtype field should be configured as 0001.

[0119] Solution 2: Use the preemption request frame as a management frame (such as an Action Frame). The frame type field should be configured as 00 and the subtype field should be configured as 1111.

[0120] Accordingly, when the device that needs to be preempted has other frames to send, the preemption request PreEmptReq can be attached to the existing frame for transmission to reduce additional overhead. For example, if the device that needs to be preempted happens to have control frames such as CTS, BA, BSR to transmit, the preemption request can be attached to the current control frame for transmission, without sending a separate preemption request frame.

[0121] In one example, when there are at least two stations that simultaneously send the first preemption request to the AP, the identified low-latency service is preferentially processed, including:

[0122] The AP prioritizes the low-latency services to be transmitted at each site according to the maximum time value and maximum data volume value of the tolerable delay of the low-latency services to be transmitted at each site, and sends a second preemption indication to the corresponding site in order from high to low priority. After receiving the second preemption indication, each site starts to send low-latency services to the AP in turn.

[0123] Specifically, the devices with low-latency services to be transmitted uniformly send preemption requests (PreEmptReq) to the AP, that is, when there are at least two sites that send the first preemption request to the AP at the same time, the AP prioritizes the low-latency services to be transmitted at each site according to the maximum time value and maximum data volume value of the tolerable delay of the low-latency services to be transmitted at each site, and sends a second preemption indication to the corresponding site in order from high to low priority. After receiving the second preemption indication, each site starts to send low-latency services to the AP in turn. Among them, the urgency of the low-latency service can be judged by multiple factors such as the delay information in PreEmptReq, whether the low-latency service is a predictable low-latency service (predictable low latency traffic) or an event-driven low-latency service (event-based low latency traffic), and the data volume of the low-latency service. The judgment method is similar to the method recorded in the aforementioned embodiment. The AP side can determine the order of low-latency service processing based on the following two judgment results: setting two thresholds, LatencyTh is used to judge the urgency of the low-latency service, that is, when the maximum tolerable delay configured for the low-latency service is less than LatencyTh, it means that the low-latency service is more urgent; setting the second threshold LLPacketSizeTh, when the data volume of the low-latency service is greater than LLPacketSizeTh, it means that the low-latency service data volume is large and needs to be processed first.

[0124] In another example, when there are at least two stations that simultaneously send the first preemption request to the AP, the identified low-latency service is preferentially processed, including:

[0125] The AP sends a second preemption indication to the station that competes for the channel based on a preset competition strategy to instruct the station to start sending low-latency services to the AP, and sends an interruption indication to the station that is currently transmitting non-low-latency services to instruct the station to suspend the current transmission of non-low-latency services or prohibit participating in channel competition.

[0126] Specifically, the device with low-latency service competes for the channel according to the competition strategy of the prior art (802.11be), that is, when there are at least two stations that send the first preemption request to the AP at the same time, the device that competes for the channel transmits data packets of the low-latency service. At this time, the AP can send an interrupt indication to the device without low-latency service to suspend transmission or instruct it not to participate in channel competition. The interrupt indication can be attached to the beacon frame (Beacon) or other broadcast frame for transmission.

[0127] In one example, after the low-latency service is transmitted, the low-latency service transmission method also includes: if there is still a margin in the current TXOP, continue to transmit the interrupted non-low-latency service; if the current TXOP is exhausted, retransmit the interrupted non-low-latency service.

[0128] Specifically, in order to ensure the transmission quality of low-latency services, when low-latency services preempt the channel resources of other services being transmitted, resulting in the loss or damage of data packets of these services, a corresponding remediation mechanism is required to ensure the data integrity and reliability of the preempted services. By judging whether there is still margin in the current TXOP, it is determined whether to continue to transmit the interrupted non-low-latency services. If there is still margin in the current TXOP, the interrupted non-low-latency services are continued to be transmitted; if the current TXOP is exhausted, the interrupted non-low-latency services are retransmitted.

[0129] Accordingly, considering that the reason for the retransmission of the interrupted non-low-latency service is that the resources are preempted by the low-latency service, not because of the bad channel conditions or other inherent factors, for the retransmission of the data packets of the non-low-latency service, in order to minimize the negative impact of the preemption, it can be assigned a higher priority and retransmitted first.

[0130] In one example, when retransmitting an interrupted non-low-latency service, the backoff window of the non-low-latency service is configured to be smaller than the backoff window before the interruption, and / or the access category of the non-low-latency service is mapped to the access category with the highest priority.

[0131] Specifically, when retransmitting an interrupted non-low-latency service, a smaller backoff window CW (smaller than the backoff window before the interruption) can be configured for the non-low-latency service so that the non-low-latency service has a greater probability of competing for the right to channel access and completing the transmission.

[0132] Alternatively, the priority of the interrupted non-low-latency service is mapped to the access category with the highest priority, namely AC_VO. In this way, no matter what the priority originally assigned to the retransmitted data is, it will be uniformly mapped to AC_VO. Correspondingly, the low-latency service will also use the EDCA parameters corresponding to AC_VO, including AIFS, CWmin, CWmax, TXOP limit, etc. It should be noted that the method of assigning a higher priority to the non-low-latency service whose retransmission is interrupted can be similar to the above-mentioned method of assigning the highest priority to the low-latency service. It is only necessary to replace the low-latency service in the above scheme with the interrupted non-low-latency service in this embodiment, and this application will not repeat it here.

[0133] In another example, if the transmission process of a low-latency service fails, the identified low-latency service is given priority, including: retransmitting the low-latency service that failed to transmit, and the number of retransmissions is not greater than a retransmission threshold.

[0134] Specifically, when the low-latency service device seizes the channel and transmits data, there may also be a transmission failure. In order to ensure the transmission quality of the low-latency service and minimize the impact on the interrupted service and other devices, this embodiment imposes certain restrictions on the retransmission mechanism of the low-latency service. When the low-latency service that fails to transmit is retransmitted, the number of retransmissions is not greater than the retransmission threshold. For example, a maximum retransmission threshold LLRetryLimit can be set for the low-latency service. If the number of retransmissions of the low-latency service exceeds the threshold, the low-latency service will stop retransmission and release channel resources to allow other services to have a chance to transmit. There are two ways to configure the maximum retransmission threshold LLRetryLimit. One is to use the existing parameter in the current system: dot11ShortRetryLimit, but it should be noted that the configuration of this parameter for the low-latency service should be different from that for the non-low-latency service, for example, the number of retransmissions of the low-latency service can be higher. Another configuration method is to configure the number of retransmissions for the low-latency service alone, for example, define a new parameter dot11LLShortRetryLimit for the retransmission of the low-latency service alone.

[0135] Regarding the value of the retransmission threshold for low-latency services, in order to ensure the transmission stability of higher priority data, data packets with higher access category priority or stricter latency requirements should be allowed a higher number of retransmissions. Therefore, event-driven low-latency services should have larger LLRetryLimit values ​​than predictable low-latency services. Low-latency services with stricter latency requirements should also have higher LLRetryLimit values. For example, a latency requirement interval or threshold can be set. If the latency requirement of the current low-latency service is less than the threshold, or within a certain interval, a higher LLRetryLimit value is configured.

[0136] In addition, during the retransmission process of low-latency services, low-latency service devices are allowed to change parameter configurations such as MCS (Modulation and Coding Scheme) and OMI to adapt to changes in channel quality and reduce the bit error rate and packet loss rate of data packets, but this will also reduce the transmission rate and throughput.

[0137] In another example, if the TXOP occupied by the low-latency service is about to be exhausted, but the low-latency data has not been transmitted yet, the identified low-latency service is given priority, which also includes: the station transmitting the low-latency service sends a first preemption request to the AP to request the AP to agree to the station preempting the next TXOP, and after the request is approved, continues to transmit the low-latency service in the next TXOP.

[0138] If the low-latency service has been transmitted and there is still room in the occupied TXOP, the identified low-latency service is given priority, which also includes: the station transmitting the low-latency service sends a first sharing request to the AP to request the AP to agree to share the remaining room in the occupied TXOP for the AP or other stations to transmit data.

[0139] Specifically, the device transmitting the low-latency service / station transmitting the low-latency service sends the first preemption request in the current TXOP to request the AP to agree that the station preempts the next TXOP, and after the request is agreed, it reserves the next TXOP and continues to transmit the low-latency service in the next TXOP. Fig.16 As shown, STA2 can send PreEmptReq in the AP's TXOP, reserve the following TXOP, and send low-latency data packets in the following TXOP. If there is still room in TXOP after the low-latency data packet is transmitted, the TXOP can be shared with AP or other STAs to transmit data. The above settings can ensure that low-latency service devices have priority in transmitting data in the next TXOP, avoiding the overhead and uncertainty of competing for channels again.

[0140] In another example, if the TXOP occupied by the low-latency service is about to be exhausted, but the low-latency data has not been transmitted, the identified low-latency service is given priority, which also includes: the station transmitting the low-latency service competes for the subsequent TXOP within the current TXOP to continue transmitting the low-latency service in the subsequent TXOP.

[0141] The station transmitting the low-latency service starts to compete for the subsequent transmission opportunity within the current TXOP. The competition strategy can be as described in the above embodiment: configure a higher priority AC for the low-latency service or classify it into a new AC with the highest priority, so that it has a shorter backoff time, shorter AIFS and longer TXOP limit in the competition channel, so that it has a greater probability of competing for the subsequent transmission opportunity and can send more data frames. Similarly, if there is still room in the TXOP after the low-latency service transmission is completed, the TXOP can be shared with the AP or other STA to transmit data, thereby reducing the time for the low-latency service device to wait for the next TXOP to start, and there is no need to send additional preemption requests.

[0142] Compared with the related art, the above-mentioned embodiments of the present application take into account the situations that may arise during the transmission of low-latency services and design the preemption strategy, conflict handling and retransmission mechanism of low-latency services during the preemption process of low-latency services, so as to ensure the reliability of low-latency service transmission while also ensuring the data integrity and reliability of the preempted services and channel resources, avoid wasting extra waiting time, save channel resources, reduce the computing burden and control complexity of the AP, and improve the robustness and scalability of the system.

[0143] Another embodiment of the present application relates to a low-latency service transmission method. This embodiment is a supplement to the aforementioned embodiment and specifically relates to the following contents.

[0144] Under the 802.11ax standard, the AP uses orthogonal frequency division multiplexing (OFDMA) technology to divide the channel into multiple resource units (RUs), allowing different terminals to occupy different RUs to achieve multi-user parallel transmission. The AP can optimize the allocation of RU resources from a global perspective during uplink and downlink transmission.

[0145] In a downlink multi-user orthogonal frequency division multiplexing (OFDMA) mechanism, in one example, the identified low-latency services are prioritized, including:

[0146] In the downlink multi-user orthogonal frequency division multiplexing mechanism, the access point AP preferentially allocates resource units RU or spatial streams to the station to receive low-latency services, and completes the transmission of low-latency services with the station based on the preferentially allocated resource units or spatial streams. Specifically, for the downlink multi-user OFDMA operation, when the AP has multiple data frames to be sent to multiple STAs respectively, it is up to the AP to decide how to allocate RU or spatial streams to different STAs. If the AP side has low-latency services to transmit at this time, the AP side should preferentially allocate RU or stream to the STA to receive low-latency services.

[0147] In an example, under the orthogonal frequency division multiplexing mechanism of uplink multiple users, the identified low-latency services are given priority, including:

[0148] In the uplink multi-user orthogonal frequency division multiplexing mechanism, the access point AP allocates resources to each site based on the buffer status feedback BSR obtained from each site; among them, resource units are preferentially allocated to sites that contain information about low-latency services in the BSR; sites that need to be allocated resources are notified through trigger frames, and service transmission is completed with each site based on the allocated resource units.

[0149] Specifically, for uplink multi-user OFDMA, in order to allocate resources, the AP can actively request or passively collect the terminal's cache status (i.e., BSR feedback). The AP performs global resource allocation based on the BSR information, and after the allocation is completed, it initiates a transmission process through the trigger frame mechanism. At this time, if there is a low-latency service to be transmitted on the STA side, it can be notified through BSR. Based on the received low-latency service information, the AP can prioritize the allocation of RUs or spatial streams to the STA with low-latency services to be sent, and notify each STA that needs to be allocated resources through the trigger frame.

[0150] In one example, a method for transmitting information of a low-latency service based on a BSR includes:

[0151] A bit indicating low-latency services is added to the BSR control subfield format. When the bit is configured as a preset value, the service corresponding to the high-priority access category indicated in the ACI high subfield is a low-latency service, and the corresponding Queue Size High corresponds to the queue length of the low-latency service. When the bit is configured as a non-preset value, it indicates that there is no low-latency service in the queue. The preset value is 1 or 0.

[0152] Specifically, Fig.17 As shown, the ACI high subfield in the existing BSR control subfield format specifies the high-priority AC determined by the STA. For a STA with a low-priority service to transmit, this field should specify the AC corresponding to the low-priority service, and the corresponding Queue Size High should also be configured with the Queue size corresponding to the low-priority service. The ACI Bitmap subfield corresponds to four different access categories, namely: B0 corresponds to AC_BE, B1 corresponds to AC_BK, B2 corresponds to AC_VI, and B3 corresponds to AC_VO.

[0153] Specifically, when indicating low-latency services in the BSR feedback sent by each site, 1 bit can be added to the BSRcontrol subfield format to indicate the low-latency service Low Latency Indication (the bit indicating the low-latency service). That is, if the Low Latency Indicationsubfield is 1, it means that the service corresponding to the high-priority AC indicated in the ACI high subfield is a low-latency service, and the corresponding Queue Size High also corresponds to the queue length of the low-latency service. If the Low Latency Indicationsubfield is 0, it means that there is no low-latency service in the queue. The BSR control subfield format is as follows: Fig.18 It should be noted that regarding the configuration of the Lowlatency indication subfield, considering the forward compatibility of the WiFi protocol, if this parameter is not configured, it means that special processing for low-latency services is not supported.

[0154] In another example, a method for transmitting information of a low-latency service based on a BSR includes: creating an independent access category with the highest priority for the low-latency service in advance;

[0155] Add the relevant bits of the access category for low-latency services in the ACI bitmap and ACI High of the BSR control subfield format, and update the mapping table of the ACI bitmap.

[0156] Specifically, an independent access category AC_LL with the highest priority is created in advance for low-latency services, and the EDCA parameters of the access category are set. The corresponding BSR control subfield format should also be adjusted accordingly. Fig.19 As shown, first, the access category of low-latency services needs to be added to the ACI bitmap, and the corresponding ACI High should also add the ACI corresponding to the low-latency service access category, so the ACI bitmap and ACI High need to increase 1 bit each. Correspondingly, the mapping of the ACI bitmap also needs to be updated as follows: B0 corresponds to AC_BE, B1 corresponds to AC_BK, B2 corresponds to AC_VI, B3 corresponds to AC_VO, and B4 corresponds to AC_LL.

[0157] The access categories of low-latency services may include: an access category of event-driven low-latency services and an access category of predictable low-latency services, and the priority of the access category of event-driven low-latency services is higher than the priority of the access category of predictable low-latency services. That is, the two TIDs corresponding to the access type AC_LL of the low-latency service may be respectively predictable low-latency services and event-driven low-latency services, and the event-driven low-latency services should have a higher priority than the predictable low-latency services.

[0158] In addition, the 802.11ax standard also provides an optional random access mechanism (UORA: Uplink OFDMA Random Access). Under this mechanism, the allocation of RU resources in the uplink UL-OFDMA link is not controlled by the AP, but is obtained by the terminal through UORA competition. This access mechanism does not rely on the terminal to feedback BSR information in real time.

[0159] In another example, under the random access mechanism in the uplink multi-user OFDM, the identified low-latency services are given priority, including:

[0160] In the random access mechanism of orthogonal frequency division multiplexing of uplink multi-users, the access point AP allows the station to transmit low-latency services to directly select the minimum value of OCW from the trigger frame sent by the access point AP to perform the backoff step, or the access point AP configures a separate OCW value for the station to transmit low-latency services, so that the station can successfully compete for resources, so that the station can complete the transmission of low-latency services with the access point AP based on the resource unit competed for.

[0161] Specifically, in the UORA mechanism, a frequency domain backoff technology (i.e., OFDMA back-off, OBO) is adopted. In the OBO technology, the AP first sends a trigger frame. The OCW (OFDMA contention window) field in the trigger frame (within the UORA Parameter Set Information field) indicates the range of the contention window and identifies the RU resources that can be used for random access (i.e., eligible RA-RUs, RUs that can be used for Random Access). The interrupt selects a random number in the OCW and subtracts its own random number from the number of RUs that can be competed in this round until the result is 0. If the terminal obtains 0 after subtraction, it indicates that the competition is successful and a random RU is selected for occupation. If the terminal does not obtain 0 after subtraction, it indicates that the competition has failed, and the value is retained and subtracted in the next round.

[0162] The Association Identifier (AID) is a unique identifier assigned by the AP to the STA when the AP and the STA establish a connection. The AID field is also included in the User Info field of the trigger frame (each RU has an AID indication). This AID field indicates whether the RU can be used for random access, specifically including:

[0163] If AID = 0, it means that this RU is used for one or more associated terminals to perform random access;

[0164] If AID = 2045, it means that this RU can be used for one or more unassociated terminals to perform random access;

[0165] If AID = X, where 0 < X < 2045, it means that this RU is for the specific STA with AID = X to access;

[0166] Based on the above policy, when a certain STA has low-latency services to transmit, the AP can configure a specific dedicated RU for this STA to use. The specific method is as follows: First, this STA needs to send an indication of low-latency services to notify the AP that it has low-latency services to send. This indication of low-latency services can be sent to the AP based on the BSR in the above text, or the method designed by the PreEmptReq in Embodiment 2 can be used to inform the AP that it has low-latency services to send and requires the allocation of a dedicated RU. In addition, the AP can also configure dedicated RU resources for such STAs according to the transmission of historical services. For example, if a certain STA often has low-latency services in transmission, or if the current low-latency service is a predictable low-latency service, dedicated RU resources can be configured for such STAs.

[0167] On the other hand, in the OBO technology, the STA selects a random number based on the OCW configuration in the trigger frame sent by the AP and starts the backoff process. To ensure the fast access of low-latency services, low-latency services should be allowed to directly select the minimum value of OCW for the backoff process. The range of OCW can be expressed as [OCWmin, OCWmax]. Therefore, for the STA that wants to send low-latency services, it can fixedly select OCWmin as the initial value of the backoff. Or a separate OCW can also be configured for low-latency services, that is, OCW_LL = [OCWmin_LL, OCWmax_LL]. This OCW_LL should be a smaller value than the conventional OCW configuration, that is, OCWmin_LL ≤ OCWmin, OCWmax_LL ≤ OCWmax.

[0168] Compared with the related art, the above-mentioned embodiment of the present invention combines the transmission of low-latency services with orthogonal frequency division multiplexing (OFDMA) technology, and adds 1 bit in the BSR control subfield format to indicate the low-latency service Low Latency Indication or adds a new access category in the uplink and downlink multi-user OFDMA operations, so that the AP can preferentially allocate RU to the STA with low-latency services to be processed based on the received low-latency service information, and further ensure the reliability of low-latency service transmission under orthogonal frequency division multiplexing.

[0169] Another embodiment of the present invention relates to a low-latency service transmission system, including an access point AP and a station, wherein the access point AP and the station are used to jointly execute the low-latency service transmission method as described in any of the above embodiments. The specific implementation of the low-latency service transmission method has been recorded in the above embodiments, and this application will not repeat it here.

[0170] The contents of the above embodiments can be combined with each other without contradiction. Ordinary technicians in this field can understand that the above implementation methods are specific embodiments of the present invention, and in actual applications, the contents of the above embodiments can be changed in various forms and details without departing from the spirit and scope of the present invention.

Claims

1. A low-latency service transmission method, characterized in that: include: Identify whether the service to be transmitted is a low-latency service; as well as, Prioritize the identified low-latency services; The prioritizing of the identified low-latency services includes: Map the access category of the identified low-latency service to an access category with a higher priority, and process it preferentially according to the EDCA parameters of the mapped access category; The EDCA parameter includes a flag for indicating whether the current access category can be allocated with a low-latency service; Mapping the identified access category of the low-latency service to an access category with a higher priority includes: Determine the original access category of the low-latency service according to the TID of the identified low-latency service, and map the access category of the identified low-latency service to the first access category whose existing identification bit indicates that the low-latency service can be allocated and has a higher priority than the original access category; If there is a second access category with a higher priority than the first access category and the identification bit indicates that low-latency services can be allocated, the identified low-latency services are mapped from the first access category to the second access category according to the urgency of the identified low-latency services.

2. The method according to claim 1, characterized in that: Identify whether the service to be transmitted is a low-latency service; And, prioritize identified low-latency services, including: Create an independent access category with the highest priority for low-latency services in advance and set the EDCA parameters for the access category; Determine whether the service to be transmitted is a low-latency service according to the access category of the service to be transmitted; The identified low-latency services are processed preferentially according to the EDCA parameters of their corresponding access categories.

3. The method according to claim 2, characterized in that The low-latency service includes at least: predictable low-latency service and event-driven low-latency service; The step of pre-creating an independent access category with the highest priority for the low-latency service and setting EDCA parameters for the access category includes: Access categories and EDCA parameters of the access categories are set in advance for the predictable low-latency service and the event-driven low-latency service respectively; wherein the priority of the access category of the event-driven low-latency service is higher than the priority of the access category of the predictable low-latency service.

4. The method according to claim 1, characterized in that Map the access categories of identified low-latency services to access categories with higher priority, including: The identified access category of the low-latency service is mapped to the existing access category AC_VO with the highest priority.

5. The method according to claim 4, characterized in that When mapping the access category of the low-latency service to the existing access category with the highest priority, the method further includes: Reconfigure the EDCA parameters of the mapped access category; The prioritizing the identified low-latency services according to the mapped EDCA parameters of the access category includes: The identified low-latency services are given priority according to the reconfigured EDCA parameters of the mapped access categories.

6. The method according to claim 5, characterized in that The low-latency service includes at least: predictable low-latency service and event-driven low-latency service; The reconfiguring of the EDCA parameters of the mapped access category includes: After the access categories of the predictable low-latency service and the event-driven low-latency service are mapped respectively, the EDCA parameters of the two mapped access categories are reconfigured differently so that the event-driven low-latency service has a higher priority than the access category of the predictable low-latency service.

7. The method according to claim 1, characterized in that The prioritizing of the identified low-latency services includes: Pre-set time thresholds and data volume thresholds for describing the delay that low-latency services can tolerate; According to the relationship between the maximum time value and the maximum data volume value of the tolerable delay indicated in the configuration information of the low-latency service and the time threshold and the data volume threshold, the access category of the identified low-latency service is mapped to the existing access category; wherein, the smaller the time value is than the time threshold, and / or the larger the data volume value is than the data volume threshold, the higher the priority of the corresponding existing access category mapped thereto; The identified low-latency services are processed preferentially according to the EDCA parameters of the mapped access category.

8. The method according to claim 1, characterized in that When the low-latency service is a low-latency service sent by a TXOP holder, the prioritizing the identified low-latency service includes: The TXOP holder immediately inserts the transmission of the low-latency service after completing the transmission of the non-low-latency service being transmitted, and then receives a BA containing feedback of the non-low-latency service replied by the receiving end of the non-low-latency service.

9. The method according to claim 8, characterized in that When the non-low-latency service and the low-latency service are sent to the same receiving end, the BA replied by the receiving end and received by the TXOP holder also includes feedback of the low-latency service.

10. The method according to claim 8, characterized in that When the non-low-latency service and the low-latency service are sent to two different receiving ends, after the TXOP holder completes the transmission of the non-low-latency service being transmitted, the following steps are further included: The TXOP holder requests the receiving end of the non-low-latency service to suspend the feedback of BA. After the low-latency service transmission is completed and the BA fed back by the receiving end of the low-latency service is obtained, the TXOP holder sends a BAR to the receiving end of the non-low-latency service in order to obtain the BA fed back by the receiving end.

11. The method according to claim 1, characterized in that: When the low-latency service is a low-latency service sent by a TXOP holder, the prioritizing the identified low-latency service includes: After receiving the data packet of the low-latency service, the TXOP holder immediately interrupts the currently transmitted non-low-latency service and starts transmitting the low-latency service. After the transmission is completed, according to the delay requirement of the interrupted non-low-latency service, if there is no timeout, the interrupted non-low-latency service will continue to be transmitted. If there is a timeout, the interrupted non-low-latency service will be retransmitted.

12. The method according to claim 1, characterized in that When the low-latency service is a low-latency service sent by a TXOP responder, and the TXOP responder is an access point AP and the TXOP holder is a station other than the access point AP, the step of giving priority to the identified low-latency service includes: The AP sends a first preemption indication to the station to instruct the station to interrupt the non-low-latency service being transmitted by the AP; The station sends confirmation information of the first preemption indication to the AP; after receiving the confirmation information of the first preemption indication, the AP starts to transmit the low-latency service to the receiving end.

13. The method according to claim 1, characterized in that When the low-latency service is a low-latency service sent by a TXOP responder, and the TXOP responder is a station other than an access point AP, and the TXOP holder is an access point AP, the prioritizing the identified low-latency service includes: The station sends a first preemption request to the AP to request the AP to agree that the station preempts the current TXOP; If the AP agrees that the station preempts the current TXOP, the AP will interrupt the transmission of the non-low-latency service between the AP and the station, and send a second preemption indication to the station. After receiving the second preemption indication, the station starts to send the low-latency service to the AP. If the AP does not agree that the station preempts the current TXOP, the AP ignores the first preemption request and continues to transmit non-low-latency traffic with the station.

14. The method according to claim 1, characterized in that When the low-latency service is a low-latency service sent by a third-party site that is not a TXOP holder and a TXOP responder, the prioritizing the identified low-latency service includes: The third-party station sends a second preemption request to the AP in the TXOP to request the AP to agree that the third-party station preempts the current TXOP; If the AP agrees that the third-party station preempts the current TXOP, the AP will interrupt the transmission of non-low-latency services between the station and the TXOP, and send a second preemption indication to the third-party station. After receiving the second preemption indication, the third-party station starts to send low-latency services to the AP. If the AP does not agree that the third-party station preempts the current TXOP, the AP ignores the second preemption request and continues to transmit non-low-latency traffic with the stations in the TXOP.

15. The method according to any one of claims 12 to 14, characterized in that: The preemption request and the preemption indication are sent as separate control frames or management frames, respectively, or are sent attached to other control frames or management frames.

16. The method according to claim 13, characterized in that When there are at least two stations that simultaneously send the first preemption request to the AP, the identified low-latency service is preferentially processed, including: The AP prioritizes the low-latency services to be transmitted at each site according to the maximum time value and maximum data volume value of the tolerable delay of the low-latency services to be transmitted at each site, and sends a second preemption indication to the corresponding site in order from high to low priority. After receiving the second preemption indication, each site starts to send low-latency services to the AP in turn.

17. The method according to claim 13, characterized in that When there are at least two stations that simultaneously send the first preemption request to the AP, the identified low-latency service is preferentially processed, including: The AP sends a second preemption indication to the station that competes for the channel based on a preset competition strategy to instruct the station to start sending low-latency services to the AP, and sends an interruption indication to the station that is currently transmitting non-low-latency services to instruct the station to suspend the current transmission of non-low-latency services or prohibit participating in channel competition.

18. The method according to any one of claims 12 to 14, characterized in that: After the low-latency service is transmitted, the method further includes: If there is still margin in the current TXOP, the interrupted non-low-latency service continues to be transmitted; if the current TXOP is exhausted, the interrupted non-low-latency service is retransmitted.

19. The method according to claim 18, characterized in that When retransmitting an interrupted non-low-latency service, the backoff window of the non-low-latency service is configured to be smaller than the backoff window before the interruption, and / or the access category of the non-low-latency service is mapped to the access category with the highest priority.

20. The method according to any one of claims 12 to 14, characterized in that: If the transmission process of the low-latency service fails, the identified low-latency service is preferentially processed, including: The low-latency service that fails in transmission is retransmitted, and the number of retransmissions is not greater than a retransmission number threshold.

21. The method according to any one of claims 12 to 14, characterized in that: If the TXOP occupied by the low-latency service is about to be exhausted, but the low-latency service has not been fully transmitted, the prioritizing the identified low-latency service further includes: The station transmitting the low-latency service sends a first preemption request to the AP to request the AP to agree that the station preempts the next TXOP, and after the request is agreed, continues to transmit the low-latency service in the next TXOP.

22. The method according to any one of claims 12 to 14, characterized in that: If the TXOP occupied by the low-latency service is about to be exhausted, but the low-latency service has not been fully transmitted, the prioritizing the identified low-latency service further includes: The station transmitting the low-delay service competes for the following TXOP in the current TXOP to continue transmitting the low-delay service in the following TXOP.

23. The method according to any one of claims 12 to 14, characterized in that: If the low-latency service has been transmitted and the occupied TXOP has a margin, the prioritizing the identified low-latency service also includes: The station transmitting the low-latency service sends a first sharing request to the AP to request the AP to agree to share the remaining capacity of the seized TXOP for the AP or other stations to transmit data.

24. The method according to claim 1, characterized in that The prioritizing of the identified low-latency services includes: In the orthogonal frequency division multiplexing mechanism of downlink multi-user, the access point AP preferentially allocates resource units or spatial streams to the site to receive the low-latency service, and completes the transmission of the low-latency service with the site based on the preferentially allocated resource units or spatial streams.

25. The method according to claim 1, characterized in that The prioritizing of the identified low-latency services includes: In the uplink multi-user OFDM mechanism, the access point AP allocates resources to each site based on the buffer status feedback BSR obtained from each site. Among them, resource units are preferentially allocated to sites that contain information about low-latency services in the BSR. The stations that need to be allocated resources are notified through trigger frames, and the service transmission is completed with each station based on the allocated resource units.

26. The method according to claim 25, characterized in that The method of transmitting low-latency service information based on BSR includes: A bit indicating low-latency services is added to the BSR control subfield format. When the bit is configured as a preset value, the service corresponding to the high-priority access category indicated in the ACI high subfield is a low-latency service, and the corresponding Queue Size High corresponds to the queue length of the low-latency service; when the bit is configured as a non-preset value, it indicates that there is no low-latency service in the queue; The preset value is 1 or 0.

27. The method according to claim 25, characterized in that The method of transmitting low-latency service information based on BSR includes: Create independent, highest-priority access classes in advance for low-latency services; The bits related to the access category of the low-latency service are added to the ACI bitmap and ACI High of the BSR control subfield format, and the mapping table of the ACI bitmap is updated.

28. The method according to claim 27, characterized in that The access category of the low-latency service includes: an access category of event-driven low-latency service and an access category of predictable low-latency service, and the priority of the access category of the event-driven low-latency service is higher than the priority of the access category of the predictable low-latency service.

29. The method according to claim 25, characterized in that The prioritizing of the identified low-latency services includes: In the random access mechanism of orthogonal frequency division multiplexing of uplink multi-users, the access point AP allows the station to transmit low-latency services to directly select the minimum value of OCW from the trigger frame sent by the access point AP to perform the backoff step, or the access point AP configures a separate OCW value for the station to transmit low-latency services, so that the station can successfully compete for resources, so that the station can complete the transmission of low-latency services with the access point AP based on the resource unit competed for.

30. A low-latency service transmission system, characterized in that: It comprises an access point AP and a station, wherein the access point AP and the station are used to jointly execute the low-delay service transmission method as described in any one of claims 1 to 29.

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