Uplink Delay Indication Method and Access Point

Abstract

An uplink (UL) delay indication method, comprising: an access point (AP) collects delay information associated with communication with at least one non-AP station (STA), without asking the at least one non-AP station (STA) for delay measurement; performs statistical analysis on the delay information to generate at least one uplink delay indicator.

Description

[0001] Related References

[0002] This disclosure is part of a non - provisional patent application and claims priority to U.S. Provisional Patent Application No. 63 / 038,942, filed on June 15, 2020, the entire content of which is incorporated herein by reference. Technical Field

[0003] This disclosure generally relates to wireless communication, and more particularly, to methods and apparatuses for collecting delay information and generating uplink delay indicators on the access point side. Background Art

[0004] Unless otherwise indicated herein, the methods described in this section are not prior art to the claims listed below and are not admitted to be prior art by inclusion in this section.

[0005] In a Wireless Fidelity (WiFi) communication system, an access point (AP) can provide various statistical information on downlink (DL) delay, such as transmission delay, queue delay, and channel access delay. DL delay statistics can be provided to non - AP stations (STAs) so that each non - AP STA can use such DL delay information to select a basic service set (BSS) or link to associate with. The delay statistics obtained on the AP side are only for DL traffic. Since most information is available on the non - AP STA side, it is typically difficult for the AP side to know the uplink (UL) delay. Therefore, an innovative design is needed to enable the AP side to provide a UL delay indicator without asking the non - AP STA side for delay measurements. Summary of the Invention

[0006] The following summary of the invention is illustrative only and not intended to be limiting in any way. That is, the following overview is provided to introduce concepts, highlights, benefits, and advantages of the novel and non - obvious technologies described herein. The selected implementations are further described in the detailed description below. Accordingly, the following overview is not intended to identify essential features of the claimed subject matter nor to be used to determine the scope of the claimed subject matter.

[0007] One object of the present invention is to provide methods and apparatuses for collecting delay information and generating uplink delay indicators on the access point side.

[0008] According to a first aspect of the present invention, an exemplary uplink (UL) delay indication method is disclosed. The exemplary UL delay indication method includes: collecting, by an access point (AP), delay information associated with communication with at least one non-AP station (STA) without asking the at least one non-AP station for delay measurement; performing statistical analysis on the delay information to generate at least one uplink delay indicator.

[0009] According to a second aspect of the present invention, an exemplary access point (AP) is disclosed. The exemplary AP includes a data collection circuit and a data processing circuit. The data collection circuit is arranged to collect delay information associated with communication with at least one non-AP station (STA) without asking the at least one non-AP station for delay measurement. The data processing circuit is configured to perform statistical analysis on the delay information to generate at least one uplink delay indicator.

[0010] According to a third aspect of the present invention, an exemplary uplink (UL) delay indication method is disclosed. The exemplary UL delay indication method includes: collecting, by an access point (AP), delay information associated with communication with at least one non-AP station (STA), where the delay information is not provided by the at least one non-AP station; performing statistical analysis on the delay information to generate at least one uplink delay indicator.

[0011] After reading the following detailed description of the preferred embodiments shown in the various figures and drawings, these and other objects of the present invention will undoubtedly become apparent to those of ordinary skill in the art. Description of the Drawings

[0012] Figure 1 A diagram showing a Wi-Fi communication system according to an embodiment of the present invention.

[0013] Figure 2 A diagram showing a first AP-side UL delay information collection design according to an embodiment of the present invention.

[0014] Figure 3 A diagram showing a second AP-side UL delay information collection design according to an embodiment of the present invention.

[0015] Figure 4 A diagram showing a diagram of a third AP-side UL delay information collection design according to an embodiment of the present invention.

[0016] Figure 5 A diagram showing a diagram of a fourth AP-side UL delay information collection design according to an embodiment of the present invention.

[0017] Figure 6 A diagram showing a diagram of a fifth AP-side UL delay information collection design according to an embodiment of the present invention.

[0018] Figure 7 A diagram showing a design for collecting UL delay information on the sixth AP side according to an embodiment of the present invention. Detailed implementation

[0019] In the following description and claims, specific terms are used which refer to specific elements. As those skilled in the art will appreciate, electronic device manufacturers may refer to an element by a different name. This document is not intended to distinguish between elements that have different names but the same function. In the following description and claims, the terms "comprising" and "including" are used in an open-ended manner and should therefore be interpreted as "including but not limited to...". Additionally, the term "coupled" is intended to mean an indirect or direct electrical connection. Thus, if a device is coupled to another device, that connection may be through a direct electrical connection, or through an indirect electrical connection via other devices and connections.

[0020] Figure 1 A diagram of a Wireless Fidelity (WiFi) communication system according to an embodiment of the present invention. The WiFi communication system 100 has a plurality of wireless communication devices, including an Access Point (AP) 102 and one or more non-AP Stations (STA) 104_1 - 104_N (N ≧ 1). For example, the AP 102 and the non-AP STA 104_1 - 104_N comply with the IEEE 802.11ax and IEEE 802.11be standards. In this embodiment, the AP 102 includes a controller 106, a Receiver (RX) circuit 108, and a Transmitter (TX) circuit 110, where the controller 106 is coupled to the RX circuit 108 and the TX circuit 110, and includes a data acquisition circuit 112 and a data processing circuit 114. It should be noted that Figure 1 only the elements relevant to the present invention are shown. In practice, the AP 102 is allowed to include additional elements for implementing other specified functions. The AP 102 communicates with the non-AP STA 104_1 - 104_N via the RX circuit 108 and the TX circuit 110. For example, the RX circuit 108 can be used to process the uplink (UL) traffic 102 from any one of the non-AP STA 104_1 - 104_N to the AP, and the TX circuit 110 can be used to process the downlink (DL) traffic from the AP 102 to any one of the non-AP STA 104_1 - 104_N.

[0021] The data acquisition circuit 112 is arranged to acquire the latency information INF_L associated with the communication of the non-AP STAs 104_1 - 104_N without querying the non-AP STAs 104_1 - 104_N for latency measurement. The latency information INF_L is locally acquired by the AP 102. In other words, the latency information INF_L is acquired by the AP 102 itself, rather than provided by the non-AP STAs 104_1 - 104_N. The data processing circuit 114 is coupled to the data acquisition circuit 112 and is arranged to perform a statistical analysis on the latency information INF_L to generate one or more uplink latency indicators IND. There is no limitation on the algorithm for performing the statistical analysis on the acquired latency information INF_L. For example, the statistics of the latency information INF_L can cover the average value, percentile, histogram, etc. Referring to the accompanying drawings, further details of the proposed AP-side UL latency indicator scheme are described.

[0022] In a first exemplary UL latency indicator design, each UL latency indicator IND generated from the data processing circuit 114 is a buffer state-based UL latency indicator. The AP 102 can use trigger frames to trigger UL traffic, and triggered-based (TB) UL transmissions become more important. The buffer state of the non-AP STA 104_i (1 ≤ i ≤ N) can be reported in a request or non-request manner and can be carried by the Quality of Service (QoS) control field or the High Throughput (HT) control field. For example, the Media Access Control (MAC) header of a MAC frame includes a QoS control field and an HT control field, where the length of the QoS control field is 2 octets and the length of the HT control field is 4 octets. Regarding the 16-bit QoS control field, bits 0 - 3 represent the Traffic Identifier (TID). When bit 4 of the QoS control field is set to 1, the queue size subfield is specified in bits 8 - 15 of the QoS control field. The QoS control field exists in QoS data frames and QoS Nullframes and can be used to carry the buffer state of the non-AP STA through the queue size subfield. For example, the queue size subfield indicates the number of buffered traffic of a given traffic category (TC) or traffic stream (TS) at the non-AP STA that sends the frame containing this subfield. In other words, the queue size subfield (bits 8 - 15) carries the buffer state of the TID (bits 0 - 3) of the non-AP STA.

[0023] The HT control field always appears in the Control Wrapper frame, as well as in QoS data frames, QoS null frames, and management frames. The HT control field has three variants: the HT variant, the Very High Throughput (VHT) variant, and the HE variant. The variant format is distinguished by the values of the first two bits B0 and B1 of the HT control field. When the first two bits B0 and B1 are 1, it indicates that the HT control field contains the HE variant. The HE variant of the HT control field has an A-Control subfield set by bits B2 - B31 of the HT control field. The Aggregate Control (A-Control) subfield of the HE variant is 30 bits long, and the Control Identifier (ID) subfield (4 bits) of the A-Control subfield can indicate that the Control Information subfield (26 bits) of the A-Control subfield carries a buffer status report (BSR) by specifying a value (e.g., control ID = 3).

[0024] The non-AP STA 104_i (1 ≤ i ≤ N) can report its buffer status in a requested manner. For example, when receiving a buffer status report polling (BSRP) frame from the AP 102, the non-AP STA 104_i (1 ≤ i ≤ N) can respond to the control field of the BSRP frame using the A-Control BSR in the HT control field or the QueueSize (QS) in QoS. In addition, the non-AP STA 104_i (1 ≤ i ≤ N) is allowed to report its buffer status in an unsolicited way. For example, the non-AP STA 104_i (1 ≤ i ≤ N) can actively report its buffer status using the A-Control BSR in the HT control field or the QS in the QoS control field when there is no BSRP from the AP 102.

[0025] Figure 2It is a diagram designed for collecting the UL delay information on the first AP side according to an embodiment of the present invention. In this embodiment, the TX circuit 110 of the AP 102 can send a BSRP frame 202 to the non-AP STA 104_i (1≤i≤N), the RX circuit 108 of the AP 102 can receive a BSR (which is the requested BSR) 204 from the non-AP STA 104_i, and then the TX circuit 110 of the AP 102 can send a trigger frame (TF) 206 to the non-AP STA 104_i to trigger the transmission of an uplink trigger-based physical layer protocol data unit (UL TBPPDU) 208. Specifically, the BSRP / BSR pair provides a protocol for the AP 102 to obtain the buffer status of each access category (AC) on the non-AP STA 104_i, so that the AP 102 can send a trigger frame to trigger the uplink traffic from the non-AP STA 104_i. The delay between the arrival of the requested BSR 204 and the response to the trigger frame 206 can be regarded as the UL delay. The delay information INF_L collected by the data acquisition circuit 112 may include a time delay, which is the time delay between the moment T1 when the AP 102 receives the BSR (which is the requested BSR) 204 and the moment T2 when the AP 102 sends the trigger frame 206. The AP 102 sends the trigger frame 206 in response to the BSR (which is the requested BSR) 204 to trigger the UL traffic from the non-AP STA 104_i.

[0026] Figure 3 It is a diagram designed for collecting the UL delay information on the second AP side according to an embodiment of the present invention. In this embodiment, the non-AP STA 104_i (1≤i≤N) can use an unsolicited BSR to report the buffer status of each of its ACs to the AP 102. Refer to Figure 3, the RX circuit 108 of the AP 102 receives a BSR (which is an unsolicited BSR) 302 from a non-AP STA 104_i (1 ≤ i ≤ N). Then, the TX circuit 110 of the AP 102 can send a trigger frame (TF) 304 to the non-AP STA 104_i to trigger the transmission of a UL TB PPDU 306. The latency from the arrival of the unsolicited BSR 302 to the response of the trigger frame 304 can be regarded as the UL latency. The latency information INF_L collected by the data acquisition circuit 112 may include the time delay between the moment T3 when the AP 102 receives the BSR (which is an unsolicited BSR) 302 and the moment T4 when the AP 102 sends the trigger frame 304. The AP 102 sends the trigger frame 304 in response to the BSR (which is an unsolicited BSR) 302 to trigger UL traffic from the non-AP STA 104_i.

[0027] The latency INF_L is collected by the AP 102 itself and records multiple time delays, each representing the BSR-based UL latency between the AP 102 and one of the non-AP STAs 104_1 - 104_N. As described above, the data processing circuit 114 performs statistical analysis on the latency information INF_L to generate one or more uplink latency indicators IND. In some embodiments of the present invention, the data processing circuit 114 may generate a UL latency indicator IND for each access category (AC).

[0028] The BSR can be solicited or unsolicited. In some embodiments of the present invention, the data processing circuit 114 may generate a UL latency indicator IND as the UL latency indicator based on the solicited BSR, and may generate another UL latency indicator IND as the UL latency indicator based on the unsolicited BSR. Specifically, the data processing circuit 114 generates a first UL latency indicator by performing statistical analysis on the time delays, each time delay being between the moment when the AP 102 receives the solicited BSR and the moment when the AP 102 sends a trigger frame in response to the solicited BSR; and further generates a second UL latency indicator by performing statistical analysis on the time delays, each time delay being between the moment when the AP 102 receives the solicited BSR and the moment when the AP 102 sends a trigger frame in response to the unsolicited BSR.

[0029] The buffer status can also be reported by using the QoS control field. The latency information INF_L is collected by the AP 102 itself and records multiple time delays, each time delay representing the QoS-based UL latency between the AP 102 and one of the non-AP STAs 104_1 - 104_N.

[0030] Figure 4FIG. is a diagram designed for collecting UL delay information on the third AP side according to an embodiment of the present invention. In this embodiment, the TX circuit 110 of the AP 102 can send the BSRP frame 202 to the non-AP STA 104_i (1 ≤ i ≤ N), the RX circuit 108 of the AP 102 can receive the QS (which is the requested QS) 404 from the non-AP STA 104_i, and then the TX circuit 110 of the AP 102 can send a trigger frame (TF) 206 to the non-AP STA 104_i to trigger the transmission of the UL TB PPDU 208. The delay between the arrival of the requested QS 404 and the response to the trigger frame 206 can be regarded as the UL delay. The delay information INF_L collected by the data acquisition circuit 112 can include the time delay between the moment T1' when the AP 102 receives the QS (which is the requested QS) 404 and the moment T2' when the AP 102 sends the trigger frame 206. The AP 102 sends the trigger frame 206 in response to the QS (which is the requested QS) 404 to trigger the UL traffic from the non-AP STA 104_i.

[0031] Figure 5 FIG. is a diagram designed for collecting UL delay information on the fourth AP side according to an embodiment of the present invention. In this embodiment, the non-AP STA 104_i (1 ≤ i ≤ N) can report its buffer status to the AP 102 using an unsolicited QS. Referring to Figure 5 , the RX circuit 108 of the AP102 receives the QS (which is the unsolicited QS) 502 from the non-AP STA 104_i (1 ≤ i ≤ N), and then the TX circuit 110 of the AP 102 can send a trigger frame (TF) 304 to the non-AP STA 104_i to trigger the transmission of the UL TB PPDU 306. The delay between the arrival of the unsolicited QS 502 and the response to the trigger frame 304 can be regarded as the UL delay. The delay information INF_L collected by the data collection circuit 112 can include the time delay between the moment T3' when the AP 102 receives the QS (which is the unsolicited QS) 502 and the moment T4' when the AP102 sends the trigger frame 304. The AP102 sends the trigger frame 304 in response to the QS (which is the unsolicited QS) 502 to trigger the UL traffic from the non-AP STA 104_i.

[0032] In a second exemplary UL delay indicator design, each UL delay indicator IND generated from the data processing circuit 114 is a periodic UL traffic delay indicator. The current BSRP / BSR provides a protocol for the AP to obtain the buffer status of each access category (AC) on the non-AP STA, so that the AP can send trigger frames to trigger uplink traffic. However, using BSRP / BSR cannot meet the requirements of delay-sensitive traffic applications, such as game control and industrial automation. Specifically, for delay-sensitive and periodic UL traffic, waiting for the AP's BSRP is not sufficient to meet the jitter requirement and cannot guarantee the latency. To solve this problem, the Aggregation Control (A-Control) subfield can be used for the transmission of traffic indication between the AP and the non-AP STA. For example, the first two bits B0 and B1 of the HT control field are 1, and the HE variant of the HT control field has an A-Control subfield set by bits B2 - B31 of the HT control field, where the control ID subfield (4 bits) of the A-Control subfield is set by a specified value to indicate that the traffic indication information is carried by the control information subfield (up to 26 bits) of the A-Control subfield. It should be noted that the traffic indication information carried by the A-Control subfield is only informative and is not used to negotiate with the AP.

[0033] In this embodiment, the UL traffic required by delay-sensitive traffic applications can be periodic UL traffic, and the traffic indication information can include multiple parameters to describe the characteristics of the periodic traffic. For example, the traffic indication information carried by the control information subfield of the A-Control subfield can include parameters such as "Period", "Delta Period", and "TrafficSize". The parameter "Period" indicates the period of the periodic traffic. "Delta Period" indicates the incremental time from the current frame carrying the A-control subfield to the moment when the non-AP STA 104_i (1 ≤ i ≤ N) transmits the periodic traffic. The parameter "Traffic Size" indicates the traffic size of the periodic traffic. Ideally, with the traffic indication information carried by the A-Control subfield, the characteristics of the periodic UL traffic required by delay-sensitive traffic applications are known to the AP 102, and the AP 102 can allocate appropriate resources in advance and can trigger UL transmissions from the non-AP STA 104_i in a timely manner.

[0034] Figure 6This is a diagram designed according to the fifth AP - side UL delay information collection in an embodiment of the present invention. The RX circuit 108 of AP 102 receives traffic indication information sent from non - AP STA 104_i (1 ≤ i ≤ N), where the traffic indication information is carried by the control information sub - field of the A - Control sub - field, and includes timing information of the UL traffic requested by non - AP STA 104_i. For example, the UL traffic requested by non - AP STA 104_i can be periodic UL traffic required by a delay - sensitive traffic application running on non - AP STA 104_i. The timing information of the periodic UL traffic can include the parameter "Period" (indicating the period P of the periodic UL traffic), and the parameter "Delta Period" (indicating the incremental time from the current frame carrying the A - Control sub - field to the moment when non - AP STA 104_i sends the periodic UL traffic). Thus, AP 102 can refer to the sent traffic indication information to know that at time T5 a trigger frame is requested to trigger UL traffic from non - AP STA 104_i, and at time T7 another trigger frame is requested to trigger UL traffic from non - AP STA 104_i. However, due to interference, the occupation of transmission opportunities (TXOP) of other non - AP STAs, and / or the scheduling of the AP, AP 102 may not be able to trigger non - AP STA 104_i on time. The jitter from the request start time of the trigger frame can be used as an indicator of how AP 102 can serve the requests of non - AP STAs and can be regarded as the UL delay. In this embodiment, the delay information INF_L collected by the data collection circuit 112 includes the time delay between the moment T5 when the trigger frame 602 is requested by the traffic indication information and the moment T6 when AP 102 actually sends the trigger frame 602 to trigger UL traffic from non - AP STA 104_i, and the time delay between the moment T7 when the trigger frame 604 is requested by the traffic indication information and the moment T8 when AP 102 actually sends this trigger frame 604 to trigger UL traffic from non - AP STA 104_i. The data processing circuit 114 performs statistical analysis on the delay information INF_L (including jitter information) to generate an uplink delay indicator IND. In other words, the statistics of the jitter provide UL delay information for the periodic UL traffic requested by non - AP STAs.

[0035] Figure 7This is a diagram designed according to the sixth AP - side UL delay information collection of the embodiments of the present invention. The target wake time (TWT) allows the STA to manage the activities in the BSS by scheduling the STA to operate at different times, in order to minimize contention and reduce the amount of time required for the STA using the power management mode to wake up. For example, each non - AP STA 104_i (1 ≤ i ≤ N) can negotiate a single TWT with the AP 102, and can have a specified service period (SP), during which the non - AP STA can wake up to receive DL traffic 102 from the AP or transmit UL traffic to the AP 102. Any single TWT SP designated for the non - AP STA 104_i is a determined time period for DL / UL transmission. As Figure 7 shown, a single TWT SP 702 agreed upon between the AP 102 and the non - AP STA 104_i should start at time T9. However, due to interference, TXOP occupancy of other non - AP STAs, and / or scheduling of the AP, the AP 102 may not be able to initialize the single TWT SP 702 on time. The jitter from the SP start time to the actual frame exchange can be used as an indicator of how the AP 102 serves the single TWT of the non - AP STA, and can be regarded as the UL delay. In the third exemplary UL delay indicator design, each UL delay indicator IND generated from the data processing circuit 114 is a single TWT SP delay indicator. Therefore, the waiting time information INF_L collected by the data acquisition circuit 112 includes the time delay between the start time T9 of the single TWT 702 designated for the non - AP STA 104_i and the moment T10 when the AP 102 starts the actual frame exchange with the non - AP STA 104_i during the single TWT 702. The data processing circuit 114 performs a statistical analysis on the waiting time information INF_L (which includes jitter information) to generate the UL delay indicator IND. In other words, the statistics of the jitter provide the delay information of the single TWN agreed upon between the AP and the non - AP STA.

[0036] Those skilled in the art will easily observe that various modifications and changes can be made to the apparatus and methods while retaining the teachings of the present invention. Therefore, the above disclosure should be construed as being limited only by the limitations and boundaries of the appended claims.

Claims

1. An uplink delay indication method, comprising: Collecting, by an access point, delay information associated with communication with at least one non-access point station without querying the at least one non-access point station for delay measurement; Performing statistical analysis on the delay information to generate at least one uplink delay indicator and receiving a buffer status from one of the at least one non-access point stations; Wherein the delay information includes: A time delay between a moment when the access point receives the buffer status and a moment when the access point sends a trigger frame in response to the buffer status to trigger uplink traffic from the one of the at least one non-access point stations.

2. The uplink delay indication method according to claim 1, wherein The at least one uplink delay indicator is calculated by the access point.

3. The uplink delay indication method according to claim 1, characterized in that The step of performing statistical analysis on the delay information to generate the at least one uplink delay indicator includes: Generating an uplink delay indicator for each access category.

4. The uplink delay indication method according to claim 1, characterized in that The step of performing statistical analysis on the delay information to generate the at least one uplink delay indicator includes: Generating a first uplink delay indicator by performing statistical analysis on a plurality of time delays, each time delay being between a moment when the access point receives a requested buffer status and a moment when the access point sends a trigger frame in response to the requested buffer status; and Generating a second uplink delay indicator by performing statistical analysis on a plurality of time delays, each time delay being between a moment when the access point receives an unsolicited buffer status and a moment when the access point sends a trigger frame in response to the unsolicited buffer status.

5. An uplink delay indication method, comprising: Collecting, by an access point, delay information associated with communication with at least one non-access point station without querying the at least one non-access point station for delay measurement; Performing statistical analysis on the delay information to generate at least one uplink delay indicator, and Receiving traffic indication information from one of the at least one non-access point stations, wherein the traffic indication information contains timing information of uplink traffic and is carried by a control information subfield in an aggregation control (A-Control) subfield; Wherein, the delay information includes: A time delay between a moment when a trigger frame is requested by the traffic indication information and a moment when the access point sends the trigger frame to trigger the uplink traffic from the one of the at least one non-access point stations.

6. The uplink delay indication method according to claim 5, wherein The traffic indication information carried by the aggregation control subfield is informative and is not used for negotiation with the access point.

7. The uplink delay indication method according to claim 5, characterized in that, A delay-sensitive traffic application requires the uplink traffic.

8. The uplink delay indication method according to claim 5, wherein The uplink traffic is periodic uplink traffic.

9. An uplink delay indication method, comprising: Collecting, by an access point, delay information associated with communication with at least one non-access point station without querying the at least one non-access point station for delay measurement; Performing statistical analysis on the delay information to generate at least one uplink delay indicator, wherein the delay information includes: A time delay between a start time of a single target wake time service period designated for one of the at least one non-access point station and a moment when the access point starts an actual frame exchange with the one of the at least one non-access point station during the single target wake time service period.

10. An access point, comprising: A data acquisition circuit arranged to acquire delay information associated with communication with at least one non-access point station without interrogating the at least one non-access point station for delay measurement; A data processing circuit arranged to perform statistical analysis on the delay information to generate at least one uplink delay indicator; A receiver circuit arranged to receive a buffer status from one of the at least one non-access point station; And A transmitter circuit arranged to send a trigger frame in response to the buffer status to trigger uplink traffic from the one of the at least one non-access point station; Wherein the delay information includes: A time delay between a moment when the access point receives the buffer status and a moment when the access point sends the trigger frame.

11. The access point according to claim 10, characterized in that, The data processing circuit is arranged to generate an uplink delay indicator for each access category.

12. The access point according to claim 10, characterized in that, The data processing circuit is arranged to: generate a first uplink delay indicator by performing statistical analysis on a plurality of time delays, each time delay between a moment when the access point receives a requested buffer status and a moment when the access point sends a trigger frame in response to the requested buffer status; And generate a second uplink delay indicator by performing statistical analysis on a plurality of time delays, each time delay between a moment when the access point receives an unsolicited buffer status and a moment when the access point sends a trigger frame in response to the unsolicited buffer status.

13. An access point, comprising: A data acquisition circuit arranged to acquire delay information associated with communication with at least one non-access point station without interrogating the at least one non-access point station for delay measurement; A data processing circuit arranged to perform statistical analysis on the delay information to generate at least one uplink delay indicator; A receiver circuit arranged to receive traffic indication information from one of the at least one non-access point station, wherein the traffic indication information contains timing information of uplink traffic and is carried by a control information subfield in an aggregation control (A-Control) subfield; And A transmitter circuit arranged to send a trigger frame to trigger uplink traffic from the one of the at least one non-access point station; Wherein, the delay information includes: A time delay between a moment when a trigger frame is requested by the traffic indication information and a moment when the access point sends the trigger frame.

14. The access point according to claim 13, characterized in that, The traffic indication information carried by the aggregation control subfield is informative and not used for negotiation with the access point.

15. The access point according to claim 13, characterized in that, A delay-sensitive traffic application requires the uplink traffic.

16. The access point according to claim 13, characterized in that, The uplink traffic is periodic uplink traffic.

17. An access point, comprising: A data acquisition circuit, which is arranged to acquire delay information associated with communication with at least one non-access point station, without interrogating the at least one non-access point station for delay measurement; A data processing circuit, which is arranged to perform statistical analysis on the delay information to generate at least one uplink delay indicator, wherein the delay information includes: A time delay, which is between a start time of a single target wake-up time service period designated for one of the at least one non-access point stations and a moment when the access point starts an actual frame exchange with the one of the at least one non-access point stations during the single target wake-up time service period.

Images