US20110222520A1

US20110222520A1 - ADVERTISEMENT OF QUALITY OF SERVICE (QoS) INFORMATION FOR NETWORK MANAGEMENT TRAFFICE IN A WIRELESS LOCAL AREA NETWORK (WLAN)

Info

Publication number: US20110222520A1
Application number: US13/045,622
Authority: US
Inventors: Michael Peter Montemurro; Stephen McCann
Original assignee: Research in Motion Ltd
Current assignee: BlackBerry Ltd
Priority date: 2010-03-15
Filing date: 2011-03-11
Publication date: 2011-09-15
Also published as: US11368880B2; JP2013522999A; CN102893690A; TW201210385A; US9615383B2; AU2011228702A1; AU2011228701A1; CN102893689A; TW201208453A; BR112012023395A2; US20210136630A1; KR101501996B1; TWI457029B; EP2548401B1; JP2014131305A; US20190289501A1; US20120008605A2; JP2013523000A; CA2696037A1; BR112012023385A2

Abstract

An access point advertises a management frame quality of service (MFQ) policy that defines an access category used for transmitting a first type of management frame. Each mobile station associated with the access point is to prioritize transmission of management frames according to the MFQ policy advertised by the access point, unless a policy configuration request for the mobile station to prioritize transmission of management frames according to a different MFQ policy has been accepted.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Canadian patent application 2,696,037 filed Mar. 15, 2010, entitled “Advertisement and Dynamic Configuration of WLAN Prioritization States”, the content of which is incorporated by reference in its entirety.

TECHNICAL FIELD

The technology described herein generally relates to wireless local area networks (WLANs), and more particularly, to the handling of network management traffic in a WLAN.

BACKGROUND

The enhanced Distributed Channel Access (EDCA) of the Institute of Electrical and Electronics Engineers (IEEE) standard 802.11 is an enhancement to the original IEEE 802.11 Media Access Control (MAC) sublayer and is a method of medium access described in the standard amendment document IEEE 802.11e. EDCA provides four prioritized queues for transmission, where each queue is associated with a different access category (AC). The four access categories defined, for example, in IEEE standard 802.11e, in decreasing priority, are AC_VO, AC_VI, AC_BE and AC_BK, named for voice traffic, video traffic, best-effort traffic, and background traffic, respectively. The queues use a contention-based mechanism to determine the next frame for transmission. The queue parameters are set such that the high priority queues have a preference for access to the wireless medium.
Management frames are the foundation of network management traffic in a Wireless Local Area Network (WLAN). Current IEEE 802.11 standards dictate that, in any access point (AP) or non-AP station (STA), management frames are to be handled via the EDCA queue of highest priority.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustration of an example network architecture for advertisement of management frame QoS (MFQ) information within a basic service set (BSS);

FIG. 2 is an illustration of an example method to be implemented by an access point (AP) for advertisement of MFQ information;

FIG. 3 is an illustration of an example method to be implemented by an AP for including MFQ information in a downlink frame;

FIG. 4 is an illustration of an example method to be implemented by a station (STA) associated with an AP for handling MFQ information received from the AP in a downlink frame;

FIG. 5 is an illustration of example formatting information for a MFQ element;

FIG. 6 is an illustration of an example method to be performed by a STA associated with an AP for requesting permission from the AP to deviate from MFQ information currently advertised by the AP, receiving a policy configuration response from the AP, and acting on the received policy configuration response;

FIG. 7 is an illustration of an example method to be performed by an AP for receiving a policy configuration request from an associated STA for permission to deviate from MFQ information currently advertised by the AP and for responding to the policy configuration request;

FIG. 8 is an illustration of example formatting for a policy configuration request;

FIG. 9 is an illustration of example formatting for a policy configuration response;

FIG. 10 is an illustration of example formatting for a policy stop message;

FIG. 11 is a block diagram of an example AP;

FIG. 12 is a block diagram of an example STA;

FIG. 13 is a block diagram of a media access control (MAC) sublayer module of an AP; and

FIG. 14 is a block diagram of a MAC sublayer module of a STA.

DETAILED DESCRIPTION

The disclosure can be better understood with reference to the following drawings and description. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the disclosed technology. Moreover, in the figures, like referenced numerals designate corresponding parts or elements throughout the different views. The following description is merely exemplary in nature and is in no way intended to limit the disclosure, its application, or uses. As used herein, the term “module” refers to an Application Specific Integrated Circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or group) and memory that executes one or more software or firmware programs stored in the memory, a combinational logical circuit, and/or other suitable components that provide the described functionality. Herein, the phrase “coupled with” is defined to mean directly connected to or indirectly connected through one or more intermediate components. Such intermediate components may include both hardware and software based components.
Recent amendments to the IEEE 802.11 family of standards have increased the number and type of management frames, resulting in an increase in network management traffic. If all management frames continue to be handled as frames of the highest priority, this may adversely affect overall network performance or the ability to provide Quality of Service (QoS) to data frames or both. For example, it would not be desirable for the transmission of diagnostic reports to reduce the quality of a voice call.
By way of introduction, the disclosure is related to the prioritization of management frames and are merely exemplary in nature. More particularly, the present disclosure describes the implementation of prioritization scheme(s) that define various access categories of different management frames, where each of the access categories is associated with a respective prioritization used for transmission. An access category may be defined for a group of management frame subtypes or for an individual management frame subtype.
In the present disclosure, access categories AC_BK, AC_BE, AC_VI and AC_VO named for background traffic, best-effort traffic, video traffic, and voice traffic, respectively, are used to illustrate the concepts described herein. However, it is contemplated that the list of access categories may be different. If the list of access categories is different, then the number or definition or both of access-category-dependent queues in a compatible media access control (MAC) sublayer will also be different. An access category is a label given to a common set of enhanced distributed channel access (EDCA) parameters that are used, for example, by a station to contend for a channel in order to transmit information with certain priorities. In other words, each respective access category (e.g., AC_BK, AC_BE, AC_VI and AC_VO) is associated with (i.e., characterized by or indicative of) a respective priority used for transmission by a station.
Each data frame generated by an application in a non-access point (non-AP) station (STA) already has an indication of its priority. As used herein, the term “data frame” includes both a content data frame and a signaling data frame. For example, any one or any combination of the following values is an example indication of the priority of a data frame: a user priority assigned to the data frame; the IP-ToS (Internet Protocol—Type of Service) value in an IP header of the data frame; and a Differentiated Services Code Point (DSCP) value in the IP header of the data frame. The classification of a data frame to an access category by a MAC sublayer module of a non-AP STA may be based upon the data frame's indication of priority. For example, data frames having various user priorities may be classified as follows:


	User Priority	Access Category

	001	AC_BK
	010	AC_BK
	000	AC_BE
	011	AC_BE
	100	AC_VI
	101	AC_VI
	110	AC_VO
	111	AC_VO

Conventionally, management frames, in contrast to data frames, do not have an indication of priority, so there is no inherent classification of a management frame to an access category. Management frames are generated within the MAC sublayer module of an AP and/or a STA.
As proposed in the present disclosure, the prioritization scheme includes a default management frame QoS (MFQ) policy, which is a static definition of access categories for management frames. The default MFQ policy is implementable by a MAC sublayer module of an AP or non-AP STA. The default MFQ policy is known to all APs and STAs and is therefore not advertised. An example default MFQ policy includes the following definitions, where the access category of management frames not included in the following table is AC_BE:


		Access
	Management Frame Subtypes	Category

	Beacon	AC_VO
	(Re)Association Request/Response
	Probe Request (individually addressed)
	Probe Response
	Announcement Traffic Indication Message (ATIM)
	Dissassociation
	Authentication
	Deauthentication
	Spectrum management-channel switch announcement
	QoS
	Block Ack
	Public-extended channel switch announcement
	Public-measurement pilot
	Public-TDLS Discovery Response
	Fast BSS Transition
	HT
	SA Query
	Protected Dual of Public Action-extended channel
	switch announcement
	Mesh Action-HWMP Mesh Path Selection	AC_VI
	Self Protected
	Spectrum Management	AC_BE
	Public
	Protected Dual of Public Action
	WNM
	Unprotected WNM
	Mesh Action
	Multihop Action
	Vendor-specific Protected
	Vendor-specific

As proposed in the present disclosure, a MFQ policy will apply to a basic service set (BSS), which comprises an AP and any non-AP STAs associated with the AP. Therefore, the MFQ policy in effect in one BSS may differ from the MFQ policy in effect in a different BSS. In particular, the MFQ policy in effect in a BSS may differ from the default MFQ policy. The MFQ policies in effect in different BSSs belonging to the same extended service set (ESS) may be identical to one another, but this is not necessary. The MFQ policy in effect in a BSS may change over time. The prioritization scheme for management frames of the present disclosure is therefore dynamic in that the prioritization scheme allows for changes over time in the definition of access categories for management frame subtypes.
Furthermore, as proposed herein, the AP of the BSS will determine the MFQ policy that is currently in effect in the BSS and transmit management frames according that policy. The AP advertises MFQ information that describes how the MFQ policy currently in effect in the BSS differs from the default MFQ policy. Therefore, the MFQ policy currently in effect in a BSS may be referred to as the advertised MFQ policy, even though only the differences between the MFQ policy currently in effect in the BSS and the default MFQ policy are advertised. An associated STA is therefore informed of the MFQ policy currently in effect in the BSS through receipt of the advertised MFQ information.
In accordance with the present disclosure, an associated STA may follow the MFQ policy determined by the AP with which the STA is associated. Alternatively, an associated STA may follow the MFQ policy determined by the AP with which the STA is associated unless the STA has successfully negotiated a different MFQ policy with the AP. Compliance of an associated STA to the advertised MFQ policy or to the negotiated MFQ policy is not actually checked by the AP with which the STA is associated, because prioritization of management frames is handled internally in the STA prior to transmission of the frames.
Advertisement of MFQ Policy by AP
FIG. 1 is an illustration of an example network architecture for advertisement of MFQ information by an AP of a wireless local area network (WLAN). The WLAN may be configured using IEEE 802.11 technology, and/or or other wireless communication standards including other WLAN standards, personal area network (PAN) standards, wide area network (WAN) standards, or cellular communication standards or networks for providing wireless network communications.
In the network architecture shown in FIG. 1, a WLAN access point (AP) 10 is coupled to a network 12, possibly through a wired communication interface, a satellite interface, a Worldwide Interoperability for Microwave Access (WiMAX®) communication interface, or any other suitable communication interface. AP 10 broadcasts beacon frames. Stations 14 are WLAN devices that are within range (i.e., within communication range) of AP 10 and are associated with AP 10. AP 10 and stations 14 together form a basic service set (BSS) 16. A basic service set identifier (BSSID) identifies BSS 16, and is included in every management frame sent by AP 10 or STAs 14. The MAC address of AP 10 is often used as the BSSID. The network to which BSS 16 belongs is identified by its network name, referred to as a service set identifier (SSID). Unless hidden, the SSID is included in certain downlink frames, including, for example, beacon frames and probe response frames transmitted by AP 10.
A station (STA) 18 is within range of AP 10 but is not associated with AP 10. STA 18 is therefore not part of the BSS. STA 18 may detect the existence of AP 10 by undergoing a network discovery process to identify the available wireless local area networks within range. In some implementations, the network discovery process includes the receipt by STA 18 of beacon frames broadcasted by AP 10. In some implementations, the network discovery process includes the transmission by STA 18 of a probe request frame and receipt by STA 18 of a probe response frame from AP 10 in response to the probe request frame.
A server 20 is coupled to AP 10 through network 12. In the present implementation, server 20 is local to AP 10. Alternatively, server 20 may be remote to AP 10, and the coupling of server 20 to AP 10 may occur via other networks in addition to network 12. For example, if server 20 is remote to AP 10, the coupling of server 20 to AP 10 may occur via the Internet.
As explained in further detail in this disclosure, AP 10 advertises MFQ information that describes how the current MFQ policy in effect in BSS 16 differs from the default MFQ policy, and this advertisement may be received and interpreted by associated STAs, such as STAs 14, and by non-associated STAs, such as STA 18. Upon receipt of the advertised MFQ policy, a classification of management frames of the associated STA may be adjusted in accordance with the advertised MFQ policy. A non-associated STA, such as STA 18, may use Access Network Query Protocol (ANQP) to query an AP, such as AP 10, for the advertised MFQ policy. For example, a non-associated STA that is actively scanning may issue a probe request or a Generic Advertisement Service (GAS) request on an AP's channel in order to determine what MFQ policy the AP is implementing. However, such a non-associated STA may choose not to follow that MFQ policy. It should be noted that AP 10 transmits management frames according the current MFQ policy in effect (i.e., being implemented) within BSS 16.
FIG. 2 illustrates an example method to be implemented by an AP for advertisement of MFQ information. At 22, the AP creates an advertisement of MFQ information that describes how the current MFQ policy in effect in the BSS differs from the default MFQ policy. At 24, the AP advertises the advertisement, thus advertising the current MFQ policy in effect in the BSS (i.e., the current MFQ policy). For the sake of simplicity and brevity, the present disclosure discusses one format of the advertisement generated by the AP though those skilled in the art will appreciate that other forms of the advertisement are anticipated.
In the example method illustrated in FIG. 3, the advertisement is in the form of a MFQ policy element. The MFQ policy element defines access categories of management frames and, as mentioned above, is used to advertise and exchange MFQ policy between a STA and an AP. The AP generates a MFQ policy element at 26. At 28, the AP includes the MFQ policy element in downlink frames, for example, in beacon frames or in probe response frames or in both. As part of the process of generating a beacon frame and as part of the process of generating a probe response frame, the AP may regenerate the MFQ policy element to reflect the current MFQ policy in effect in the BSS. The MFQ policy element is not reused from an earlier beacon frame or probe response frame. Rather, the MFQ policy element is generated as part of the process of generating the beacon frame or probe response frame in which the MFQ policy element is to be included.
An AP may indicate support for management frame prioritization by setting an appropriate bit, referred to herein as MFQActivated, in the Capabilities field of the Extended Capabilities information element (IE) to a value of 1 or may indicate lack of support for management frame prioritization by setting that bit to a value of 0. One of the currently reserved bits of the Capabilities field of the Extended Capabilities IE (as defined in IEEE Std 802.11-2007) may be used for this purpose. Alternatively, presence of the MFQ policy element in the downlink frame may be an indication to STAs receiving the downlink frame that MFQ is enabled, and lack of presence of the MFQ policy element in the downlink frame may be an indication to STAs receiving the downlink frame that either the AP sending the downlink frame does not support MFQ, or the AP sending the downlink frame supports MFQ and there is no change to the current MFQ policy for the AP to advertise.
When the AP changes its current MFQ policy in effect in the BSS, the change is communicated in all the beacon frames transmitted during the Delivery Traffic Indication Message (DTIM) interval following the MFQ policy change. The change may be indicated, for example, by setting a change bit to a value of 1. The change bit may be part of the MFQ policy element or may be in another part of the beacon frame. Setting the change bit to 1 in all beacon frames transmitted during the DTIM interval following the MFQ policy change will ensure that most, if not all, STAs in the BSS will be informed of a change in MFQ policy for the BSS. For example, even if a STA is in an awake state only for beacon frames that includes DTIMs and is not awake to receive other beacon frames, that STA will still be informed of the change in MFQ policy, and therefore be prompted to check the MFQ policy element in the beacon frame. However, a STA that has set its ReceiveDTIMs parameter to “No” may not receive a beacon frame that informs of a change in MFQ policy for the BSS.
FIG. 4 illustrates an example method to be implemented by a STA associated with an AP for handling MFQ information received from the AP in a downlink frame. At 30, the STA receives a downlink frame that includes a MFQ policy element. At 32, the STA configures itself to implement the advertised MFQ policy. In other words, the STA configures itself to implement the default MFQ policy modified by the content of the MFQ policy element. As such, the STA assigns an access category to each management frame according to an access category assignment indicated in the MFQ policy element (i.e., the advertised MFQ policy).
FIG. 5 illustrates example formatting information for a MFQ policy element. In order that the advertisement may be received by associated STAs and by non-associated STAs, the size of the MFQ policy element complies with any upper limit on the size of an element in non-associated mode. In one implementation, an Element ID field 34 which is 1 octet in length includes a value indicating that the element is a MFQ policy element. A length field 36 which is also 1 octet in length stores the length of the MFQ policy element. The length of the MFQ policy element may vary, because information for multiple deviations from the default MFQ policy may be included in the MFQ policy element. A MFQ policy info field 38, alternatively named “Access Category Assignment Count” field 38, is 1 octet in length and includes a value indicating the number of deviations which are included in the MFQ policy element. MFQ policy info field 38 may also include a change bit to indicate whether the MFQ policy has changed. The “Deviation from default MFQ policy for management frame subtype #1” field 40, alternatively named “Management Prioritization Policy for Category #1” field 40, “Access Category Assignment #1” field 40, or “Access Category Mapping #1” field 40, stores a first deviation to be included in the advertised MFQ policy. Optionally, additional deviations may be provided in fields 42 and 44. Fields 40, 42 and 44 are all of variable length.
Any one or any combination of the following factors may be taken into account when determining a change to a MFQ policy: detection of changes in network conditions, anticipation of changes in network conditions, detection of changes in network loading (at the BSS level or at the ESS level or both), anticipation of changes in network loading (at the BSS level or at the ESS level or both), detection of changes in AP loading, anticipation of changes in AP loading, the presence or lack of a multi-media stream, detection of changes in a multi-media stream, anticipation of changes in a multi-media stream, and other operating conditions.
Negotiated MFQ Policy
An associated non-AP STA may negotiate with the AP with which it is associated in order to deviate from the advertised MFQ policy (i.e., the configured MFQ policy). FIG. 6 illustrates an example method to be performed by a STA associated with an AP for requesting permission from the AP to deviate from the advertised MFQ policy, receiving a response from the AP, and acting on the received response.
The method begins at 46 with a STA implementing the MFQ policy configured in its MAC sublayer module. At 48, the STA transmits a policy configuration request, also referred to herein as an “MFQ Policy Config Request”, to the AP to request a change in the MFQ policy used to transmit management frames between the STA and the AP (i.e., the responding AP). In other words, a MFQ Policy Config Request is used to negotiate a change or modification to the MFQ policy between a STA and an AP with which the STA is associated. The MFQ Policy Config Request transmitted by the STA includes or indicates a change(s) to the MFQ policy being implemented. The policy configuration request may be transmitted in response to a triggering event, for example, a network problem, application-related diagnostics, or a financial transaction. At 50, the STA receives a policy configuration response from the AP.
The policy configuration request (i.e., the MFQ Policy Config Request) includes a MFQ policy element describing how a requested MFQ policy differs from the default MFQ policy. In other words, the MFQ policy element indicates a proposed change with reference to the default MFQ policy. Any one or any combination of the following factors may taken into account when determining a requested MFQ policy: detection of changes in the associated non-AP STA due to diminishing battery power levels, anticipation of changes in the associated non-AP STA due to diminishing battery power levels, detection that a current predicted motion of the non-AP STA will shortly take the non-AP STA out of radio coverage, so the requested MFQ policy prioritizes signaling frames over a poor link.
If, as shown at 52, a policy configuration response, also referred to as a “MFQ Policy Config Response”, from the AP indicates that a policy configuration request has been rejected by the AP (i.e., the proposed change(s) in the MFQ Policy Config Request has (have) been rejected), the STA that transmitted the request may continue at 46 to transmit management frames in accordance with the MFQ policy configured in its MAC sublayer module.
In this document, a “negotiated MFQ policy” is a requested MFQ policy requested in a policy configuration request that has been accepted by the AP. If, as shown at 54, a policy configuration response received from the AP indicates that a policy configuration request has been accepted by the AP (i.e., the proposed change(s) in the MFQ Policy Config Request has (have) been accepted), the STA proceeds at 56 to implement the negotiated MFQ policy by configuring its MAC sublayer module to implement the default MFQ policy modified by the content of the policy element (i.e., the proposed changes) in the policy configuration request that has been accepted. In some implementations, both the STA and the AP may transmit management frames to each other in accordance with the changes to the MFQ policy that were indicated in the MFQ Policy Config Request. The negotiated MFQ policy applies only to the associated STA that made the policy configuration request and does not apply to any other STA in the BSS.
At some point following acceptance of a policy configuration request, the AP may send a policy stop message to the STA that made the policy configuration request. Alternatively, the STA that made the policy configuration request may send a policy stop message to the AP. As long as no policy stop message has been transmitted by the AP to the STA or by the STA to the AP, the STA may continue to implement the negotiated MFQ policy. However, if the STA determines at 58 that a policy stop message has been received from the AP or transmitted by the STA, the STA may at 60 configure its MAC sublayer module according to the MFQ policy currently advertised by the AP. The AP may have changed its advertised MFQ policy during the time that the STA was configured according to the negotiated MFQ policy. After the STA has at 58 received a policy stop message from the AP or transmitted a policy stop message to the AP, the STA may wait for an advertisement of the MFQ policy currently in effect for the BSS in order to configure its MAC sublayer module in accordance with the current advertised MFQ policy.
Optionally, a policy configuration response received from the AP may indicate that the STA should retry its policy configuration request, as shown at 62. In this case, the policy configuration response may include a suggested MFQ policy (not shown) that the AP might accept upon request. At 64, the STA may transmit another policy configuration request to the AP. This policy configuration request may be the same policy configuration request that was transmitted by the STA at 48, or this policy configuration request may include a MFQ policy element received from the AP describing a suggested MFQ policy (not shown) suggested by the AP, or this policy configuration request may include a different MFQ policy element describing a different MFQ policy than the previously requested MFQ policy. After transmitting the other policy configuration request to the AP at 64, the STA receives a new policy configuration response from the AP at 50.
As an alternative to use of the policy stop message, a STA that no longer wishes to follow the negotiated MFQ policy may send to its associated AP a policy configuration request that includes an MFQ policy element identical to the MFQ policy element advertised by the associated AP. It is expected that the AP will accept a policy configuration request that is requesting the MFQ policy currently implemented in the BSS.
As an alternative to use of the policy stop message, an AP that wants a STA to stop following a negotiated MFQ policy may send to the STA a policy configuration request that includes an MFQ policy element identical to the MFQ policy element advertised by the associated AP. It is expected that the STA will interpret the policy configuration request as a command from the associated AP to stop following the negotiated MFQ policy and to begin following the advertised MFQ policy.
FIG. 7 illustrates an example method to be performed by an AP for receiving a policy configuration request from an associated STA for permission to deviate from a MFQ policy currently advertised by the AP and for responding to the request.
The method begins at 66 when the AP receives a policy configuration request from an associated STA. At 68, the AP determines the result of the policy configuration request and includes the result in a policy configuration response to be transmitted to the STA. For example, the AP may determine to accept the policy configuration request or to reject the policy configuration request. Alternatively, the AP may determine that the STA should retry the policy configuration request. In the case that the AP determines that the result of the policy configuration request is retry, the AP may optionally determine at 69 a suggested MFQ policy to include in its policy configuration response to the STA. It is contemplated that such a suggested MFQ policy may be more likely to be accepted by the AP than the requested MFQ policy in the policy configuration request received from the STA at 66.
Following the AP's determination of the result of the policy configuration request at 66 and its optional determination (if the result is retry) of a suggested MFQ policy to describe in a policy configuration response at 68, the AP transmits the policy configuration response to the STA at 70.
FIG. 8 illustrates example formatting information for a policy configuration request. A policy configuration request may be implemented as a particular type of management frame called an action frame. A Category field 72 which is 1 octet in length is set to a value for public action. A Public Action field 73 which is 1 octet in length is set to indicate a policy configuration request frame. A dialog token field 74 which is 1 octet in length is set by the STA to a value to enable the STA to keep track of its policy configuration requests. A MFQ policy element 76 field describes the particular MFQ policy that is being requested.
FIG. 9 illustrates example formatting information for a policy configuration response. A policy configuration response may be implemented as an action frame. Category field 72 is as described above for a policy configuration request. A Public Action field 78 which is 1 octet in length is set to indicate a policy configuration response frame. Dialog token field 74 is as described above for a policy configuration request and has the same value that was used to identify the policy configuration request for which this is a response. A Result Code field 80, alternatively named “Status Code” field 80, includes an indication that the AP accepts or rejects the policy configuration request to which the Dialog Token applies or that the STA should retry a request for a policy. An optional MFQ policy element field 82, applicable when the content of the Result Code field 80 comprises an indication that the STA should retry a request, describes how a suggested MFQ policy differs from the default MFQ policy. The STA may request the suggested MFQ policy in place of the originally requested MFQ policy.
FIG. 10 illustrates example formatting information for a policy stop message. A policy stop message may be implemented as an action frame. Category field 72 is as described above for a policy configuration request. A Public Action field 84 which is 1 octet in length is set to indicate a policy stop message. Dialog token field 74 is as described above for a policy configuration request and has the same value that was used to identify the policy configuration request for which this is a policy stop message.
Implementation of MFQ Policy (Default, Advertised or Negotiated)
An AP or non-AP STA may configure its MAC sublayer module to implement an MFQ policy. The MFQ policy being implemented by the MAC sublayer module may be the default MFQ policy. Alternatively, the MFQ policy being implemented by the MAC sublayer module may be the default MFQ modified by an advertised MFQ policy element. Alternatively, the MFQ policy being implemented by the MAC sublayer module may be the default MFQ policy modified by a MFQ policy element in a policy configuration request that has been accepted. While a management frame is generated within the MAC sublayer module, the management frame will be assigned to an access category as defined by the MFQ policy, and subsequently transmitted, using the respective access category. In the present implementation, the management frame is directed, based on its assigned access category, to one of four EDCA prioritized queues where each of the prioritized queues is associated with a respective access category. As such, in the present implementation, a management frame assigned to AC_VO will be transmitted using a prioritization (i.e., a transmission priority) associated with AC_VO, a management frame assigned to AC_VI will be transmitted using a prioritization associated with AC_VI, a management frame assigned to AC_BE will be transmitted using a prioritization associated with AC_BE, and a management frame assigned to AC_BK will be transmitted using a prioritization associated with AC_BK. In other words, each access category (e.g., AC_VO, AC_VI, AC_BE and AC_BK) is indicative of a distinct prioritization (i.e., transmission priority) used to transmit a particular type or subtype of management frame. Handling of the contents of the prioritized queues may follow IEEE 802.11 scheduling and transmission rules. For example, a frame scheduler schedules frames from the prioritized queues to be passed to the physical (PHY) sublayer module for transmission over a channel of a wireless medium.
FIG. 11 is a block diagram of an example AP 100. AP 10 is an example of AP 100. AP 100 comprises a processor 102 coupled to a memory 104 and to a communication interface 106. Communication interface 106 may be a wired communication interface, a satellite interface, a Worldwide Interoperability for Microwave Access (WiMAX®) communication interface, or any other suitable communication interface. AP 100 also comprises a WLAN interface 108 within a protocol stack 110 that is coupled to processor 102. WLAN interface 108 comprises a logical link control (LLC) sublayer module 112, a MAC sublayer module 114 and a PHY sublayer module 116. The BSSID of AP 100 is stored in WLAN interface 108, possibly in a register 118. The SSID of the WLAN supported by AP 100 is stored in WLAN interface 108, possibly in a register 120. MAC sublayer module 114 may be compatible with IEEE 802.11. AP 100 also comprises an antenna 122 coupled to PHY sublayer module 116. Protocol stack 110 may comprise higher layers 124. ANQP support may be implemented in MAC sublayer module 114.
Memory 104 may store an operating system 126 to be executed by processor 102. Memory 104 may store applications 128 installed in AP 100 to be executed by processor 102. Examples of applications 128 include a configuration application that enables a WLAN administrator to configure parameters of the WLAN, for example, its SSID and BSSID(s). Memory 104 may store code 130 which, when executed by processor 102, results in one or more of the methods illustrated in FIGS. 2, 3, and 7.
A default MFQ policy 132 is not advertised in the BSS. Depending upon implementation, default MFQ policy 132 may be stored in WLAN interface 108 (as illustrated) or in memory 104. Depending upon implementation, an advertised MFQ policy 133 currently implemented by WLAN MAC sublayer 114 may be stored in WLAN interface 108 (as illustrated) or in memory 104. AP 100 is able to advertise how advertised MFQ policy 133 differs from default MFQ policy 132. AP 100 may optionally store data 134 related to one or more policy configuration requests that have previously been received from one or more associated STAs and related to one or more policy configuration responses that have previously been transmitted to one or more associated STAs. Data 134 may be implemented, for example, as records in a table, where the records are maintained on a per-AID (association identifier) basis. Depending upon implementation, data 134 may be stored in WLAN interface 108 (as illustrated) or in memory 104.
AP 100 may comprise other elements that, for clarity, are not illustrated in FIG. 11. Similarly, AP 100 may comprise a subset of the elements illustrated in FIG. 11.
FIG. 12 is a block diagram of an example STA, for example, any one of STAs 14. An STA 200 comprises a processor 202 coupled to a memory 204 and optionally to one or more other wireless communication interfaces 206. For example, wireless communication interfaces 206 may comprise a short-range wireless communication interface such as a wireless personal area network interface, possibly compatible with the Bluetooth Specification Version 4.0 published 30 Jun. 2010 or its official successors. In another example, wireless communication interfaces 206 may comprise a wireless wide area network (WWAN) interface such as for cellular communications. One or more antennas 208 may be coupled to respective ones of the wireless communication interfaces 206. An antenna may be shared among more than one wireless interface.
STA 200 also comprises a WLAN interface 210 within a protocol stack 212 that is coupled to processor 202. WLAN interface 210 comprises a LLC sublayer module 214, a MAC sublayer module 216 and a PHY sublayer module 218. MAC sublayer module 216 may be compatible with IEEE 802.11. STA 200 also comprises an antenna 220 coupled to PHY sublayer module 218. Protocol stack 212 may comprise higher layers 222.
Memory 204 may store an operating system 224 to be executed by processor 202. Memory 204 may store applications 226 installed in STA 200 to be executed by processor 202. For example, applications 226 may comprise a control application to act on MFQ policy elements received from an AP. In a further example, applications 226 may comprise a Voice over Internet Protocol (VoIP) application. In yet another example, applications 226 may comprise a telephony application. Memory 204 may also store data (not shown) used by operating system 224 and applications 226.
Memory 204 may store one or more WLAN connection profiles 228, each identifying a wireless local area network by its SSID, as known in the art.
Memory 204 may store code 230 which, when executed by processor 202, results in one or more of the methods illustrated in FIGS. 4 and 6. Receipt of a downlink frame and handling of MFQ information describing an advertised MFQ policy may be implemented in MAC sublayer module 216. ANQP support may be implemented in MAC sublayer module 216.
A default MFQ policy 232 is not advertised in the BSS. Depending upon implementation, default MFQ policy 232 may be stored in WLAN interface 210 (as illustrated) or in memory 204. Depending upon implementation, a MFQ policy 233 currently implemented by WLAN MAC sublayer 216 may be stored in WLAN interface 210 (as illustrated) or in memory 204. STA 200 may optionally store data 234 related to one or more policy configuration requests made by the STA and related to one or more policy configuration responses received by the STA. STA 200 may store an indication of its requested MFQ policy and then overwrite currently implemented MFQ policy 233 with the negotiated MFQ policy upon receiving acceptance of the policy configuration request.
Memory 204 may store an audio coder-decoder (codec) 238 or a video codec 240 or both. STA 200 may comprise an audio input element 242 and an audio output element 244, both coupled to processor 202. STA 200 may comprise a video input element 246 and a video output element 248, both coupled to processor 202.
STA 200 may comprise a Global Positioning System (GPS) module 250 coupled to processor 202.
STA 200 may comprise one or more user input elements 252 coupled to processor 202. Examples of user input elements include a keyboard, a keypad, a touchscreen, a joystick, a thumbwheel, a roller, a touchpad, a trackpad, a capacitive touch pad, an optical touch pad, and any other type of navigation actuator.
STA 200 may comprise one or more user output elements coupled to processor 202, of which a display 254 is illustrated. In the event that display 254 is a touchscreen, it functions also as a user input element.
STA 200 may comprise one or more alert components 256 coupled to processor 202, to be activated in order to alert a user, for example, by sounding a buzzer, playing a ringtone, emanating light, or vibrating.
STA 200 may include mechanical interfaces, such as a power connector jack, a data interface port such as a Universal Serial Bus (USB) port, a headphone jack, and other mechanical interfaces that are not explicitly shown.
STA 200 comprises a power pack 258 that provides power to the other components of STA 200.
STA 200 may comprise other elements that, for clarity, are not illustrated in FIG. 12. Similarly, STA 200 may comprise a subset of the elements illustrated in FIG. 12.
FIG. 13 is a block diagram of a MAC sublayer module 300 of an AP, for example, MAC sublayer module 114 of AP 100. MAC sublayer module 300 uses a management frame generator 302 to generate management frames which are distributed to different memory queues by a management frame classification unit 304. Distribution to the different memory queues is done according to a MFQ policy 306 currently implemented in the BSS to which the AP belongs. Management frames of the type or types for which MFQ policy 306 defines the access category AC_VO are routed by management frame classification unit 304 through memory queue 308. Management frames of the type or types for which MFQ policy 306 defines the access category AC_VI are routed by management frame classification unit 304 through memory queue 310. Management frames of the type or types for which MFQ policy 306 defines the access category AC_BE are routed by management frame classification unit 304 through memory queue 312. Management frames of the type or types for which MFQ policy 306 defines the access category AC_BK are routed by management frame classification unit 304 through memory queue 314. In some implementations, MFQ policy 306 defines an access category other than the AC_VO access category associated with the highest priority queue 308 for at least one management frame type.
Data frames (content frames and signaling frames) received at MAC sublayer module 300 from an LLC sublayer module (not shown) of the AP, for example, LLC sublayer module 112, may be processed by a packet classification, fragmentation and encapsulation module 316 in MAC sublayer module 300 and then subsequently routed through the same memory queues as the management frames.
A scheduler 318 schedules frames from memory queues 308, 310, 312 and 314 to be passed to a PHY sublayer module of the AP, for example, PHY sublayer module 116. For example, IEEE 802.11e has separate minimum and maximum values for each access category. Within each access category, a random number is generated that represents a wait time as multiplied by a “slot time”. In IEEE 802.11a/g, a slot time is 9 microseconds. Once the wireless medium is quiet or unoccupied, a countdown begins before transmission. Each count is 9 microseconds in real time. For AC_VO queue 308, the countdown begins at a value between 31 and 127. For AC_VI queue 310, the countdown begins at a value between 127 and 255. For AC_BE queue 312, the countdown begins at a value between 255 and 511. For AC_BK queue 314, the countdown begins at a value between 511 and 1023. If the countdown is interrupted, it is paused until the wireless medium is once again quiet, and is then resumed from the value at which it was paused. If the countdowns for different queues begin at the same time, traffic in a higher priority queue will gain access to the wireless medium ahead of traffic in a lower priority queue.
MAC sublayer module 300 further comprises a MFQ policy element generator 320 which generates a MFQ policy element based on MFQ policy 306. As described previously, a MFQ policy element may be included in certain management frames generated by management frame generator 302 to advertise an advertised MFQ policy. For example, a MFQ policy element generated by MFQ policy element generator 320 may be included in a downlink frame such as a beacon frame or a probe response frame that is generated by management frame generator 302. It should be noted that, while not explicitly shown, MAC sublayer module 300 may also implement ANQP support.
FIG. 14 is a block diagram of a MAC sublayer module 400 of a STA, for example, MAC sublayer module 216 of STA 200. MAC sublayer module 400 uses a management frame generator 402 to generate management frames which are distributed to different memory queues by a management frame mapping unit 404. Distribution to the different memory queues is done according to a MFQ policy 406. Management frames of the type or types for which MFQ policy 406 defines the access category AC_VO are routed by management frame classification unit 404 through memory queue 408. Management frames of the type or types for which MFQ policy 406 defines the access category AC_VI are routed by management frame classification unit 404 through memory queue 410. Management frames of the type or types for which MFQ policy 406 defines the access category AC_BE are routed by management frame classification unit 404 through memory queue 412. Management frames of the type or types for which MFQ policy 406 defines the access category AC_BK are routed by management frame classification unit 404 through memory queue 414. In some implementations, MFQ policy 406 defines an access category other than the AC_VO access category associated with the highest priority queue 408 for at least one management frame type.
It is contemplated that MFQ policy 406 is an advertised MFQ policy. It is also contemplated that MFQ policy 406 is a negotiated MFQ policy accepted by an AP with which the STA is associated. It is also contemplated that MFQ policy 406 is the default MFQ policy.
Data frames (content frames and signaling frames) received at MAC sublayer module 400 from an LLC sublayer module (not shown) of the STA, for example, LLC sublayer module 214, may be processed by a packet classification, fragmentation and encapsulation module 416 in MAC sublayer module 400 and then subsequently routed through the same memory queues as the management frames.
A scheduler 418 schedules frames from memory queues 408, 410, 412 and 414 to be passed to a PHY sublayer module of the STA, for example, PHY sublayer module 218. For example, IEEE 802.11e has separate minimum and maximum values for each access category. Within each access category, a random number is generated that represents a wait time as multiplied by a “slot time”. In IEEE 802.11a/g, a slot time is 9 microseconds. Once the wireless medium is quiet or unoccupied, a countdown begins before transmission. Each count is 9 microseconds in real time. For AC_VO queue 408, the countdown begins at a value between 31 and 127. For AC_VI queue 410, the countdown begins at a value between 127 and 255. For AC_BE queue 412, the countdown begins at a value between 255 and 511. For AC_BK queue 414, the countdown begins at a value between 511 and 1023. If the countdown is interrupted, it is paused until the wireless medium is once again quiet, and is then resumed from the value at which it was paused. If the countdowns for different queues begin at the same time, traffic in a higher priority queue will gain access to the wireless medium ahead of traffic in a lower priority queue.
MAC sublayer module 400 further comprises a MFQ policy element generator 420 which generates a MFQ policy element based on a requested MFQ policy. As described previously, the MFQ policy element may be included in a policy configuration request generated by management frame generator 402 to negotiate a deviation from an advertised MFQ policy. It should be noted that, while not explicitly shown, MAC sublayer module 400 may also implement ANQP support.
Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

1. A method for an access point, the method comprising:

advertising a management frame quality of service (MFQ) policy,

wherein the MFQ policy defines an access category used for transmitting a first type of management frame.

2. The method as claimed in claim 1, wherein the access category includes any access category among a plurality of access categories.

3. The method as claimed in claim 1, wherein the access category is indicative of a transmission priority used for transmitting the first type of management frame, the transmission priority being any transmission priority among a plurality of transmission priorities.

4. The method as claimed in claim 3, wherein the transmission priority is not a highest priority of transmission.

5. The method as claimed in claim 3, wherein the MFQ policy further defines a second access category for a second type of management frame, the second access category being indicative of another transmission priority among the plurality of transmission priorities.

6. The method as claimed in claim 1, wherein advertising the MFQ policy comprises:

generating an element comprising an indication of how the MFQ policy differs from a default MFQ policy; and

including the element in one or more downlink frames transmitted by the access point.

7. The method as claimed in claim 1, wherein advertising the MFQ policy comprises:

generating an element that defines the access category for the first type of management frame; and

transmitting the element.

8. The method as claimed in claim 1, the method further comprising:

setting a change bit to a value indicative of a change to the MFQ policy from a previous MFQ policy.

9. The method as claimed in claim 8, the method further comprising:

setting the change bit to a second value indicative of no change once an interval has elapsed following the change.

10. A method for a mobile station within range of an access point, the method comprising:

receiving, from the access point, an advertisement of a management frame quality of service (MFQ) policy,

11. The method as claimed in claim 10, wherein the access category includes any access category among a plurality of access categories.

12. The method as claimed in claim 10, wherein the access category is indicative of a transmission priority used for transmitting the first type of management frame, the transmission priority being any transmission priority among a plurality of transmission priorities.

13. The method as claimed in claim 12, wherein the transmission priority is not a highest priority of transmission.

14. The method as claimed in claim 12, wherein the MFQ policy further defines a second access category for a second type of management frame, the second access category being indicative of another transmission priority among the plurality of transmission priorities.

15. The method as claimed in claim 10, wherein receiving the advertisement comprises:

receiving an element that defines the access category for the first type of management frame.

16. The method as claimed in claim 10, wherein receiving the advertisement comprises:

receiving a downlink frame transmitted by the access point, wherein the downlink frame includes an element comprising an indication of how the MFQ policy differs from a default MFQ policy.

17. The method as claimed in claim 16, wherein the downlink frame is a Generic Advertisement Service response frame, the method further comprising:

transmitting a request to the access point for the MFQ policy prior to receiving the Generic Advertisement Service response frame.

18. The method as claimed in claim 10, the method further comprising:

assigning the access category to management frames of the first type according to the MFQ policy.

19. The method as claimed in claim 18, the method further comprising:

transmitting the management frames using the access category.

20. An access point comprising:

a processor configured to:

advertise a management frame quality of service (MFQ) policy,

21. The access point as claimed in claim 20, wherein the access category includes any access category among a plurality of access categories.

22. The access point as claimed in claim 20, wherein the access category is indicative of a transmission priority used for transmitting the first type of management frame, the transmission priority being any transmission priority among a plurality of transmission priorities.

23. The access point as claimed in claim 22, wherein the transmission priority is not a highest priority of transmission.

24. The access point as claimed in claim 22, wherein the MFQ policy further defines a second access category for a second type of management frame, the second access category being indicative of another transmission priority among the plurality of transmission priorities.

25. The access point as claimed in claim 20, wherein the processor is further configured to:

generate an element that defines the access category for the first type of management frame; and

transmit the element.

26. A mobile station comprising:

a processor configured to:

receive, from an access point, an advertisement of a management frame quality of service (MFQ) policy,

27. The mobile station as claimed in claim 26, wherein the access category includes any access category among a plurality of access categories.

28. The mobile station as claimed in claim 26, wherein the access category is indicative of a transmission priority used for transmitting the first type of management frame, the transmission priority being any transmission priority among a plurality of transmission priorities.

29. The mobile station as claimed in claim 28, wherein the transmission priority is not a highest priority of transmission.

30. The mobile station as claimed in claim 28, wherein the MFQ policy further defines a second access category for a second type of management frame, the second access category being indicative of another transmission priority among the plurality of transmission priorities.

31. The mobile station as claimed in claim 26, wherein the processor is further configured to receive an element that defines the access category for the first type of management frame.

32. The mobile station as claimed in claim 26, wherein the processor is further configured to assign the access category to management frames of the first type according to the MFQ policy.

33. The mobile station as claimed in claim 32, wherein the processor is further configured to transmit the management frames using the access category.