Network allocation vector (NAV) setting method and device

Abstract

A network allocation vector (NAV) setting method includes, after a first access point (AP) of a multi-access point (MAP) system sends a request frame to a second AP of the MAP system to indicate that the first AP intends to share a transmission resource with the second AP, indicating that the second AP accepts use of the transmission resource shared by the first AP in response to a response frame sent from the second AP, and managing at least one of a basic NAV of a non-access point working station (STA) and an internal basic service set (intra-BSS) NAV according to the response frame, wherein the non-access point STA is associated with one of the first AP and the second AP.

Description

Technical field

[0001] The present invention relates to wireless communications, and more particularly, to a method and apparatus for processing network allocation vector (NAV) settings in a multiple access point (MAP) system. [Background Technology]

[0002] In a MAP system, multiple access points (APs) form a coordination group. These APs in the same MAP system can be regarded as member APs and can serve associated clients simultaneously. Specifically, the member APs of the same MAP system are able to share transmission resources, such as transmission opportunities (TXOPs) and target wake time (TWT) service periods (SPs), so that specific services can benefit from overlapping basic service sets (OBSS) interference mitigation and predictable transmission (TX) and reception (RX) behaviors. For example, the member APs of the same MAP system can perform joint transmission (JT) to clients associated with one or more member APs in the MAP system. For another example, the member APs of the MAP system can perform coordinated frequency division multiple access (FDMA) transmission, in which the transmission band is shared by the member APs for concurrent (at least partially time overlapping) and independent transmission on different sub-bands. For another example, the member APs of the MAP system can perform coordinated beamforming (CBF) on the same or partially overlapping frequency bands.

[0003] NAV is a virtual carrier sensing mechanism designed to reduce the need for physical carrier sensing on the air interface to save power. The Medium Access Control (MAC) frame header contains a duration field that specifies the transmission time that the wireless medium will be busy. A non-AP station (STA) monitoring the wireless medium reads the duration field and sets its NAV, which is an indicator of the time the non-AP STA must delay accessing the wireless medium. With the development of the IEEE 802.11 standard, two types of NAV were proposed, including basic NAV (i.e., inter-BSS NAV) and intra-basic service set (intra-BSS) NAV. The basic NAV is maintained and updated by receiving physical layer protocol data units (inter-PPDUs) or PPDUs that cannot be classified as inter-PPDUs or intra-PPDUs, while the intra-BSS NAV is maintained and updated only by intra-PPDUs. Therefore, when a non-AP STA supports both NAVs, an innovative NAV setting design is required to properly manage the basic NAV and intra-BSS NAV to regulate transmission behavior during sharing in a MAP system. [Summary of the invention]

[0004] An object of the present invention is to provide a method and apparatus for processing NAV settings in a MAP system.

[0005] According to a first aspect of the present invention, an exemplary network allocation vector (NAV) setting method is disclosed. The exemplary NAV setting method includes: after a first access point (AP) of a multiple access point (MAP) system sends a request frame to a second AP of the MAP system indicating that the first AP intends to share transmission resources with the second AP, in response to a response frame sent from the second AP indicating that the second AP accepts to use the transmission resources shared by the first AP, managing at least one of a basic NAV and an intra-basic service set (intra-BSS) NAV of a non-AP station (STA) according to the response frame, wherein the non-AP STA is associated with one of the first AP and the second AP.

[0006] According to a second aspect of the present invention, an exemplary network allocation vector (NAV) setting method is disclosed. The exemplary NAV setting method includes: after a first access point (AP) of a multiple access point (MAP) system sends a request frame to a second AP of the MAP system indicating that the first AP intends to share transmission resources with the second AP, in response to a response frame sent from the second AP indicating that the second AP refuses to use the transmission resources shared by the first AP, managing one of a basic NAV and an intra-basic service set (intra-BSS) NAV of a non-access point station (STA) according to the response frame, wherein the non-access point STA is associated with one of the first AP and the second AP.

[0007] According to a third aspect of the present invention, an exemplary non-access point (non-AP) station (STA) is disclosed. The exemplary non-AP STA includes a network interface circuit and a control circuit. The network interface circuit is configured to receive a response frame sent from a second access point (AP) in a multiple access point (MAP) system, indicating that the second AP accepts to use transmission resources shared by a first AP in the MAP system, after the first AP sends a request frame to the second AP indicating that the first AP intends to share transmission resources with the second AP. The control circuit is configured to manage at least one of a basic network allocation vector (NAV) and an intra-basic service set (intra-BSS) NAV of the non-AP STA based on the response frame, wherein the non-AP STA is associated with one of the first AP and the second AP.

[0008] These and other objects of the present invention will become apparent to those skilled in the art after reading the following detailed description of the preferred embodiments taken in conjunction with the figures and illustrations.

Brief Description of the Drawings

[0009] Figure 1 is a schematic diagram of a wireless communication system according to an embodiment of the present invention.

[0010] Figure 2 is a schematic diagram of a Wi-Fi system according to an embodiment of the present invention.

[0011] Figure 3 is a schematic diagram of a first NAV setting scenario according to an embodiment of the present invention.

[0012] Figure 4 is a schematic diagram of a second NAV setting scenario according to an embodiment of the present invention.

[0013] Figure 5 is a schematic diagram of a third NAV setting scenario according to an embodiment of the present invention. [Specific implementation method]

[0014] Certain terms are used in the following description and claims to refer to specific components. As skilled artisans will appreciate, electronic device manufacturers may refer to components by different names. This document does not intend to distinguish between components that differ in name but function. In the following description and claims, the terms "include" and "comprise" are used in an open-ended manner and should be interpreted as meaning "including, but not limited to..." Additionally, the term "couple" is intended to indicate either an indirect or direct electrical connection. Thus, if one device is coupled to another, that connection may be through a direct electrical connection or through an indirect electrical connection via other devices and connections.

[0015] Figure 1 1 is a schematic diagram of a wireless communication system according to an embodiment of the present invention. The wireless communication system 100 may be a Wi-Fi system that complies with the IEEE 802.11ax standard, the IEEE 802.11be standard, or the next generation Wi-Fi standard. The wireless communication system 100 includes multiple APs and multiple non-AP STAs. For simplicity and brevity, only Figure 1 104 and a non-AP STA 106 are shown. In this embodiment, APs 102 and 104 are member APs of the same MAP system, with AP 102 being a shared AP and intending to share its transmission resources with the shared AP (e.g., AP 104). For example, AP 102 uses frames, such as Multi-User Request to Send (MU-RTS) frames, to acquire a TXOP or continue an existing TXOP and intends to share the TXOP with other APs in the same MAP system. In this way, these APs can perform coordinated transmissions, such as joint transmissions, coordinated FDMA, or coordinated beamforming. In the following, the terms "AP" and "member AP" are used interchangeably.

[0016] AP 102 sends a request frame REQ to AP 104 to indicate that AP 102 intends to share its transmission resources for certain coordinated transmissions. In response to receiving the request frame REQ, AP 104 sends a response frame RSP to AP 102 to accept or reject the sharing request issued by AP 102. The request frame REQ may be a MU-RTS frame carrying sharing parameters. For example, the sharing parameters may include a sharing method (e.g., coordinated time division multiple access (TDMA), coordinated orthogonal frequency division multiple access (OFDMA), joint transmission, or coordinated beamforming), a time of a sharing period (e.g., a start time, duration, and end time), and / or coordinated beamforming parameters (e.g., a target (candidate) STA identifier (ID) and a beam change requirement indication). However, these are for illustrative purposes only and are not intended to limit the present invention.

[0017] The response frame RSP may be a Clear to Send (CTS) frame or any other response frame. The response frame RSP may carry an indication explicitly indicating whether AP 104 accepts or rejects the sharing request issued by AP 102. In an alternative design for accepting the sharing request issued by AP 102, the act of sending the response frame RSP may implicitly indicate that the sharing request was accepted by AP 104 if the response frame RSP is not a Contention-Free End (CF-end) frame. In an alternative design for rejecting the sharing request issued by AP 102, the act of not sending the response frame RSP (i.e., a "no transmission" response frame RSP) may implicitly indicate that the sharing request was rejected by AP 104 or that the request frame REQ failed to be received. When a request frame REQ is sent to AP 104 without receiving a response frame RSP from AP 104, AP 102 may use a Prioritized Interframe Space (PIFS) recovery procedure to access the wireless medium for subsequent transmission to an internal BSS station. In another alternative design of rejecting the sharing request issued by AP 102, AP 104 may send a CF-end frame as a response frame RSP.

[0018] The non-AP STA 106 supports the proposed NAV setting scheme and is a client that can associate with the MAP system through coordinated association. In this embodiment, the non-AP STA 106 can associate with one of the APs 102 and 104 of the MAP system. Figure 1As shown, non-AP STA 106 includes a processor 112, a memory 114, a control circuit 116, and a network interface circuit 117. The network interface circuit 117 may be a transceiver including a TX circuit 118 and an RX circuit 120. The memory 114 is used to store program code. The processor 112 is used to load and execute program code to manage non-AP STA 106. The control circuit 116 is used to control wireless communications with an associated AP. For example, the control circuit 116 controls the TX circuit 118 of the network interface circuit 117 to process uplink (UL) traffic and controls the RX circuit 120 of the network interface circuit 117 to process downlink (DL) traffic.

[0019] Non-AP STA 106 can maintain two NAVs: a basic NAV (i.e., inter-BSS NAV) and an intra-BSS NAV. In this embodiment, non-AP STA 106 is a client associated with an AP in a MAP system. When non-AP STA 106 (specifically, RX circuitry 120 of network interface circuitry 117) hears a request frame REQ sent from AP 102 (e.g., TXOP owner) 104, control circuitry 116 can manage at least one of the basic NAV and the intra-BSS NAV of non-AP STA 106 based on the request frame REQ. Alternatively, when non-AP STA 106 (specifically, RX circuitry 120 of network interface circuitry 117) hears a response frame RSP sent from AP 104 to AP 102 (e.g., TXOP owner), control circuitry 116 can manage at least one of the basic NAV and the intra-BSS NAV of non-AP STA 106 based on the response frame RSP. By properly setting the basic NAV and the intra-BSS NAV, transmission behavior during sharing in the MAP system can be well-regulated. The proposed NAV setting solution will be described in detail below with reference to the accompanying drawings.

[0020] Figure 2 2 is a schematic diagram of a Wi-Fi system according to an embodiment of the present invention. The Wi-Fi system 200 includes multiple APs AP1 and AP2 in the same MAP system, and also includes multiple non-access points STA1, STA2, STA3, and STA4. Non-access points STA1 and STA3 are associated with AP AP1. Non-access points STA2 and STA4 are associated with AP AP2. Non-access point STA STA3 is a hidden node of AP AP2. Non-access point STA STA4 is a hidden node of AP AP1. It is assumed that AP AP1 may be Figure 1 In the AP 102 shown in FIG, AP AP2 may be Figure 1That is, AP AP1 intends to share its transmission resources with AP AP2 for some coordinated transmission. Figure 1 The non-access point STA 106 shown in FIG may be one of the non-access point STAs STA1-STA4. That is, each non-access point STA STA1-STA4 supports the proposed NAV setting scheme and may have Figure 1 The same circuit structure as shown in .

[0021] Please combine Figure 2 and Figure 3 See. Figure 3 FIG2 is a schematic diagram illustrating a first NAV setting scenario according to an embodiment of the present invention. In this first NAV setting scenario, a sharing request is accepted. AP AP1 sends a request frame REQ to AP AP2. Since non-access points STA1 and STA3 are associated with AP AP1, they can hear the request frame REQ and treat it as an internal BSS frame. Therefore, each non-access point STA1 and STA3 sets its internal BSS NAV based on the duration information carried in the request frame REQ.

[0022] Since non-access point STA2 is not a hidden node in AP AP1, it can hear the request frame REQ. Since non-access point STA2 is not associated with AP AP1, it treats the request frame REQ as an inter-BSS frame. Therefore, non-access point STA2 sets its basic NAV based on the duration information carried in the request frame REQ. Since non-access point STA4 is a hidden node in AP AP1, it cannot hear the request frame REQ. Therefore, non-access point STA4 does not set its basic NAV.

[0023] After receiving the request frame REQ from AP1, AP2 sends a response frame RSP to indicate that AP2 accepts the use of AP1's shared transmission resources. Since non-access point STA1 is not a hidden node of AP2, it can hear the response frame RSP. Since the response frame RSP explicitly or implicitly indicates that AP2 accepts the use of AP1's shared transmission resources, non-access point STA1 treats AP2's transmissions, including the response frame RSP, as an internal BSS. Therefore, based on the response frame RSP indicating acceptance of sharing, non-access point STA1 does not need to set its basic NAV. Since non-access point STA3 is a hidden node of AP2, it cannot hear the response frame RSP. Therefore, non-access point STA3 does not need to set its basic NAV. Specifically, since non-access point STA3 can only hear the request frame REQ, it only sets its internal BSS NAV.

[0024] Since non-access point STA2 is associated with access point AP2, it can hear the response frame RSP. Since the response frame RSP explicitly or implicitly indicates that access point AP2 accepts the use of transmission resources shared by access point AP1, non-access point STA2 considers AP1's transmissions to be within the intra-BSS rather than the inter-BSS. Therefore, in response to the response frame RSP indicating acceptance of sharing, non-access point STA2 sets its intra-BSS NAV and further discontinues its basic NAV previously set in response to the request frame REQ sent by access point AP1. Alternatively, in response to the response frame RSP, non-access point STA2 sets its intra-BSS NAV and further disregards its basic NAV previously set in response to the request frame REQ sent by access point AP1. In other words, non-access point STA2 can retain the basic NAV set before access point AP2 sends the response frame RSP, but disregard it when transmission is required or requested.

[0025] Since non-access point STA4 is associated with access point AP2, it can hear the response frame RSP. Since the response frame RSP explicitly or implicitly indicates that access point AP2 accepts the use of transmission resources shared by access point AP1, non-access point STA4 considers AP1's transmission to be within the intra-BSS rather than the inter-BSS. Therefore, based on the response frame RSP indicating acceptance of sharing, non-access point STA4 sets its intra-BSS NAV. Specifically, since non-access point STA4 can only hear the response frame RSP, it only sets its intra-BSS NAV.

[0026] See also Figure 2 Combine Figure 4 . Figure 4 FIG2 is a schematic diagram illustrating a second NAV setting scenario according to an embodiment of the present invention. In this second NAV setting scenario, the sharing request is rejected. Access point AP1 sends a request frame REQ to access point AP2. Since non-access point STAs STA1 and STA3 are associated with access point AP1, they can hear the request frame REQ and treat it as an intra-BSS frame. Therefore, each non-access point STA1 and STA3 sets its intra-BSS NAV based on the duration information carried in the request frame REQ.

[0027] Since non-access point STA2 is not a hidden node from access point AP1, it can hear the request frame REQ. Since it is not associated with access point AP1, it treats the request frame REQ as an external basic service set (IBSS) frame. Therefore, non-access point STA2 sets its basic NAV based on the duration information carried in the request frame REQ. Since non-access point STA4 is a hidden node from access point AP1, it cannot hear the request frame REQ. Therefore, non-access point STA4 does not set its basic NAV.

[0028] After receiving the request frame REQ from access point AP1, access point AP2 sends a response frame RSP, indicating that access point AP2 refuses to use the transmission resources shared by access point AP1. Since non-access point STA1 is not a hidden node of access point AP2, non-access point STA1 can hear the response frame RSP. Since the response frame RSP explicitly indicates that access point AP2 refuses to use the transmission resources shared by access point AP1, non-access point STA1 is aware that there will be no transmissions from access point AP2 during the TXOP currently held by access point AP1. Therefore, based on the response frame RSP indicating the refusal of sharing, non-access point STA1 does not need to set its basic NAV. Since non-access point STA3 is a hidden node of access point AP2, non-access point STA3 cannot hear the response frame RSP. Therefore, non-access point STA3 does not need to set its basic NAV. Specifically, since non-access point STA3 can only hear the request frame REQ, non-access point STA3 only sets its intra-BSS NAV.

[0029] Since non-access point STA2 is associated with access point AP2, it can hear the response frame RSP. Since the response frame RSP explicitly instructs access point AP2 to refuse to use the transmission resources shared by access point AP1, non-access point STA2 is aware that there are no transmissions from access point AP2 during the TXOP currently owned by access point AP1. Therefore, based on the response frame RSP indicating the refusal of sharing, non-access point STA2 does not need to set its internal basic service set (intra-BSS) NAV. Specifically, during the TXOP currently owned by access point AP1, non-access point STA2 only considers AP1's transmissions as external to the basic service set (inter-BSS).

[0030] Since non-access point STA4 is associated with access point AP2, it can hear the response frame RSP. Since the response frame RSP explicitly instructs access point AP2 to refuse to use the transmission resources shared by access point AP1, non-access point STA4 is aware that there will be no transmissions from access point AP2 during the TXOP currently held by access point AP1. Therefore, based on the response frame RSP indicating the refusal of sharing, non-access point STA4 does not need to set its internal basic service set intra-BSS NAV. Specifically, non-access point STA4 can only hear the response frame RSP but does not set its internal basic service set intra-BSS NAV.

[0031] See also Figure 2 and Figure 5 . Figure 5 FIG2 is a schematic diagram illustrating a third NAV setting scenario according to an embodiment of the present invention. In this third NAV setting scenario, the sharing request is rejected. The difference between this third NAV setting scenario and the second NAV setting scenario is that AP AP2 does not respond to AP AP1's REQ as an indication of sharing rejection (or an indication of failure to receive the request frame REQ). AP AP1 sends a request frame REQ to AP AP2. Since non-access point STAs STA1 and STA3 are associated with AP AP1, they can both hear the request frame REQ and treat it as an inner BSS frame. Therefore, each non-access point STA STA1 and STA3 sets its inner BSS NAV based on the duration information carried in the request frame REQ. Since non-access point STA2 is not a hidden node of AP AP1, it can hear the request frame REQ. Since non-access point STA2 is not associated with AP AP1, it treats the request frame REQ as an outer BSS frame. Therefore, non-access point STA2 sets its basic NAV based on the duration information carried in the request frame REQ. Since non-access point STA4 is a hidden node in AP AP1, it cannot hear the request frame REQ. Therefore, non-access point STA4 does not set its base NAV. After receiving the request frame REQ from AP AP1, AP AP2 does not send a response frame. Since non-access point STAs STA1-STA4 cannot receive the response frame from AP AP2, no changes to the base NAV or internal BSSNAV introduced by the response frame are made.

[0032] Those skilled in the art will readily appreciate that many modifications and variations can be made to the apparatus and method while retaining the teachings of the present invention. Therefore, the above disclosure should be interpreted only in accordance with the scope of the appended claims.

Claims

1. A method for setting a network allocation vector (NAV), comprising: After a first access point AP of a multi-access point system sends a request frame to a second access point of the multi-access point system to indicate that the first access point intends to share transmission resources with the second access point, In response to a response frame sent from the second access point to indicate that the second access point accepts to use the transmission resources shared by the first access point, managing at least one of a basic NAV and an intra-BSS NAV of a non-access point STA according to the response frame, wherein the non-access point STA is associated with one of the first access point and the second access point. 2 . The NAV setting method as claimed in claim 1 , wherein the non-access point STA is associated with the first access point.

3. The NAV setting method of claim 2 , wherein managing at least one of the basic NAV and the internal BSSNAV according to the response frame comprises: According to the response frame, the basic NAV is not set. 4 . The NAV setting method as claimed in claim 1 , wherein the non-access point STA is associated with the second access point.

5. The NAV setting method according to claim 4, further comprising: The basic NAV is set in response to the request frame sent from the first access point.

6. The NAV setting method of claim 5 , wherein managing at least one of the basic NAV and the internal BSSNAV according to the response frame comprises: According to the response frame, the internal BSS NAV is set and the basic NAV is stopped.

7. The NAV setting method of claim 5 , wherein managing at least one of the basic NAV and the internal BSSNAV according to the response frame comprises: Based on the response frame, the internal BSS NAV is set and the basic NAV is ignored.

8. The NAV setting method of claim 4 , wherein managing at least one of the basic NAV and the internal BSSNAV according to the response frame comprises: The internal BSS NAV is set according to the response frame.

9. A method for setting a network allocation vector (NAV), comprising: After a first access point AP of a multi-access point system sends a request frame to a second access point of the multi-access point system to indicate that the first access point intends to share transmission resources with the second access point, In response to a response frame sent from the second access point to indicate that the second access point refuses to use the transmission resources shared by the first access point, managing one of a basic NAV and an intra-BSS NAV of a non-access point STA according to the response frame, wherein the non-access point STA is associated with one of the first access point and the second access point.

10. The NAV setting method as claimed in claim 9, wherein the non-access point STA is associated with the first access point.

11. The NAV setting method of claim 10 , wherein managing one of the basic NAV and the internal BSSNAV according to the response frame comprises: According to the response frame, the basic NAV is not set.

12. The NAV setting method as claimed in claim 9, wherein the non-access point STA is associated with the second access point.

13. The NAV setting method according to claim 12, further comprising: The basic NAV is set in response to the request frame sent from the first access point.

14. The NAV setting method of claim 13 , wherein managing one of the basic NAV and the internal BSSNAV according to the response frame comprises: According to the response frame, the internal BSS NAV is not set.

15. The NAV setting method of claim 12 , wherein managing one of the basic NAV and the internal BSSNAV according to the response frame comprises: According to the response frame, the internal BSS NAV is not set.

16. Non-AP stations (STAs) include: a network interface circuit configured to receive a response frame sent from a second access point (AP) of a multiple access point system to indicate that the second AP accepts to use transmission resources shared by a first AP of the MAP system, after the first AP sends a request frame to the second AP to indicate that the first AP intends to share the transmission resources with the second AP; and The control circuit is configured to manage at least one of a basic network allocation vector (NAV) and an intra-BSS (NAV) within a basic service set (BSS) of the non-AP STA according to the response frame, wherein the non-AP STA is associated with one of the first AP and the second AP. The non-AP STA of claim 16 , wherein the non-AP STA is associated with the first AP.

18. The non-AP STA of claim 17, wherein the control circuit does not set the basic NAV according to the response frame.

19. The non-AP STA of claim 16, wherein the non-AP STA is associated with the second AP.

20. The non-AP STA of claim 19, wherein the control circuit sets the intra-BSS NAV according to the response frame.

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