Patent Publication Number: US-9900759-B2

Title: Method and apparatus for peer discovery in a wireless communication network

Description:
CLAIM OF PRIORITY UNDER 35 U.S.C. §119 
     The present application for patent claims priority to Provisional Application No. 61/258,131 entitled “METHOD AND APPARATUS FOR MULTI-PROTOCOL DEVICE DISCOVERY IN WIRELESS LOCAL AREA NETWORKS (WLAN)” filed Nov. 4, 2009, and Provisional Application No. 61/292,395 entitled “METHOD AND APPARATUS FOR MULTI-PROTOCOL DEVICE DISCOVERY IN WIRELESS LOCAL AREA NETWORKS (WLAN)” filed Jan. 5, 2010, both of which are assigned to the assignee hereof and hereby expressly incorporated by reference herein. 
    
    
     BACKGROUND 
     Field 
     This disclosure relates generally to apparatus and methods for device discovery in a wireless communication network, and more particularly, the disclosure relates to peer device discovery in WLAN systems based on the IEEE 802.11 protocol (WiFi). 
     Background 
     In many telecommunication systems, communications networks are used to exchange messages among several interacting spatially-separated devices. The various types of networks may be classified in different aspects. In one example, the geographic scope of the network could be over a wide area, a metropolitan area, a local area, or a personal area, and the corresponding networks would be designated as wide area network (WAN), metropolitan area network (MAN), local area network (LAN), or personal area network (PAN). Networks also differ in the switching/routing technique used to interconnect the various network nodes and devices (e.g. circuit switching vs. packet switching), in the type of physical media employed for transmission (e.g. wired vs. wireless), or in the set of communication protocols used (e.g. Internet protocol suite, SONET (Synchronous Optical Networking), Ethernet, etc.). 
     One important characteristic of communications networks is the choice of wired or wireless media for the transmission of electrical signals among the constituents of the network. In the case of wired networks, tangible physical media such as copper wire, coaxial cable, fiber optic cable, etc. are employed to propagate guided electromagnetic waveforms which carry message traffic over a distance. Wired networks are a static form of communications networks and are typically favored for interconnection of fixed network elements or for bulk data transfer. For example, fiber optic cables are often the preferred transmission media for very high throughput transport applications over long distances between large network hubs, such as, hulk data transport across or between continents over the Earth&#39;s surface. 
     On the other hand, wireless networks are often preferred when the network elements are mobile with dynamic connectivity needs or if the network architecture is formed in an ad hoc, rather than fixed, topology. Wireless networks employ intangible physical media in an unguided propagation mode using electromagnetic waves in the radio, microwave, infrared, optical, etc. frequency bands. Wireless networks have the distinct advantage of facilitating user mobility and rapid field deployment compared to fixed wired networks. However, usage of wireless propagation requires significant active resource Management among the network users and higher levels of mutual coordination and cooperation for compatible spectrum utilization. 
     SUMMARY 
     The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects, and is intended to neither identify key or critical elements of all aspects nor delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later. 
     In an aspect, a method of peer discovery in a communications network, comprising generating a discovery request configured to identify a Tunneled Direct Link Setup (TDLS) capable peer device, transmitting the discovery request, and determining if a discovery response is received in response to the discovery request. 
     In another aspect, at least one processor configured to perform peer device discovery in a communications network comprises a first hardware module for generating a discovery request configured to identify a Tunneled Direct Link Setup (TDLS) capable peer device. Further, the at least one processor includes a second module for transmitting the discovery request, and a third module for determining if a discovery response is received in response to the discovery request. 
     In a further aspect, a computer program product for peer device discovery in a communications network comprises a non-transitory computer-readable medium, including a first set of codes executable for causing a computer to generate a discovery request configured to identify a Tunneled Direct Link Setup (TDLS) capable peer device. The non-transitory computer-readable medium further includes a second set of codes executable for causing the computer to transmit the discovery request, and a third set of codes executable for causing the computer to determine if a discovery response is received in response to the discovery request. 
     In another aspect, an apparatus for peer device discovery in a communications network comprises means for generating a discovery request configured to identify a Tunneled Direct Link Setup (TDLS) capable peer device, means for transmitting the discovery request, and means for determining if a discovery response is received in response to the discovery request. 
     In an additional aspect, a user station apparatus for peer device discovery in a communications network comprises a discovery request generator to generate a discovery request configured to identify a Tunneled Direct Link Setup (TDLS) capable peer device, a communications component to transmit the discovery request, and a discovery response determiner to determine if a discovery response is received in response to the discovery request. 
     Moreover, additional aspects may include a method for detecting and responding to discovery requests as described herein. Further aspects in this regard may include at least one processor comprising modules to perform the detecting and responding to the discovery request, a computer program product comprising computer readable medium including instructions executable by a computer to detect and respond to the discovery request, or an apparatus comprising means for or components for detecting and responding to the discovery request. 
     To the accomplishment of the foregoing and related ends, the one or more aspects comprise the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative features of the one or more aspects. These features are indicative, however, of but a few of the various ways in which the principles of various aspects may be employed, and this description is intended to include all such aspects and their equivalents. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosed aspects will hereinafter be described in conjunction with the appended drawings, provided to illustrate and not to limit the disclosed aspects, wherein like designations denote like elements, wherein dashed lines around components indicate optional elements, and in which: 
         FIG. 1  is a schematic diagram of an aspect of a wireless communication network including stations implementing discovery protocols described herein; 
         FIG. 2  is a block diagram of an aspect of a probe request that may be used in an aspect of the system of  FIG. 1 ; 
         FIG. 3  is a block diagram of an aspect of a probe response that may be used in an aspect of the system of  FIG. 1 ; 
         FIG. 4  is a block diagram of an aspect of a format of a base station set identifier (BSSID) element used in the system of  FIG. 1 ; 
         FIG. 5  is a block diagram of an aspect of a format of an Association Element used in the system of  FIG. 1 : 
         FIG. 6  is a block diagram of an aspect of an encapsulated discovery request that may be used in an aspect of the system of  FIG. 1 ; 
         FIG. 7  is a block diagram of an aspect of an encapsulated discovery response that may be used in an aspect of the system of  FIG. 1 ; 
         FIG. 8  is table of an aspect of elements of a format of a TDLS discovery request frame with a Basic Service Set Identifier (BSSID) element that may be used in an aspect of the system of  FIG. 1 ; 
         FIG. 9  is table of an aspect of elements of a format of a TDLS discovery response frame with a Basic Service Set Identifier (BSSID) element that may be used in an aspect of the system of  FIG. 1 ; 
         FIG. 10  is a block diagram of an aspect of a Link Identifier element that may be used in an aspect of the system of  FIG. 1 ; 
         FIG. 11  is a table of an aspect of contents of Link identifier fields that may be included in a discovery request and a discovery response frame used in an aspect of the system of  FIG. 1 ; 
         FIG. 12  is a table of an aspect of elements of a format of a TDLS discovery request frame with a Link Identifier element that may be used in an aspect of the system of  FIG. 1 ; 
         FIG. 13  is a table of an aspect of a format of a TDLS discovery response frame with a Link Identifier element that may be used in an aspect of the system of  FIG. 1 ; 
         FIG. 14  is a block diagram of an aspect of an Association Element, which contains information about the current association of a device, and which may be used in an aspect of the system of  FIG. 1 ; 
         FIG. 15  is a message flow diagram of an aspect of a method of Tunneled Direct Link Setup (TDLS) discovery exchange; 
         FIG. 16  is a message flow diagram of an aspect of TDLS discovery based on a broadcast TDLS setup request, followed by a TDLS setup that starts with a unicast TDLS setup request; 
         FIG. 17  is a table of an aspect of a format of possible frames used in a TDLS discovery; 
         FIG. 18  is a message flow diagram of an aspect of a Broadcast discovery request with a direct discovery response; 
         FIG. 19  is a message low diagram of an aspect of a Unicast discovery request with a direct response; 
         FIG. 20  is a message flow diagram of an aspect of a TDLS broadcast discovery with a response through the AP combined with unicast discovery with a direct response; 
         FIG. 21  is a message flow diagram of an aspect of a TDLS discovery procedure based on Probe Request and Probe Response; 
         FIG. 22  is a message flow diagram of another aspect of a TDLS discovery procedure based on Probe Request and Probe Response; 
         FIG. 23  is a message flow diagram of another aspect of a TDLS discovery procedure based on Probe Request and Probe Response, including echoing of the Probe Request; 
         FIG. 24  is a flowchart of an aspect of a method of peer device discovery in a communications network; 
         FIG. 25  is schematic diagram of an aspect of a station (STA) for performing Tunneled Direct Link Setup (TDLS) discovery in a wireless communication network; and 
         FIG. 26  is a schematic diagram of another aspect of a station (STA) for performing Tunneled Direct Link Setup (TDLS) discovery in a wireless communication network. 
     
    
    
     DETAILED DESCRIPTION 
     Various aspects are now described with reference to the drawings. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of one or more aspects. It may be evident, however, that such aspect(s) may be practiced without these specific details. 
     Referring to  FIG. 1 , in one example, popular wireless network technologies include various types of wireless local area networks (WLANs). A WLAN  100  may be used to interconnect nearby devices together, employing widely used networking protocols such as WiFi or, more generally, a member of the IEEE 802.11 wireless protocol family. 
     In one aspect, a WLAN  100  is comprised of various stations (STA), which are the components which access the wireless network. In one example, there are two types of stations (STAs): access points  102  and clients  104 ,  106 . In general, an access point serves as a hub or base station for the WLAN and a client serves as a user of the WLAN. For example, a client may be a laptop computer, a personal digital assistant (PDA), a mobile phone, etc. In one example, a client connects to an access point via a WiFi (e.g., IEEE 802.11 protocol) compliant wireless link to obtain general connectivity to the Internet or to other wide area networks. 
     In one aspect, 802.11 wireless networks may operate in two modes: infrastructure mode and ad-hoc mode. In infrastructure mode, a client or station (STA) connects to an access point (AP) which serves as a hub for connecting with other wireless clients to the network infrastructure, including, for example, Internet access. Infrastructure mode uses a client-server architecture to provide connectivity to the other wireless clients. In ad-hoc mode, wireless clients have direct connections to each other in a peer-to-peer architecture. In one aspect, 802.11 wireless networks generate a periodic Beacon signal which broadcasts wireless network characteristics (e.g., maximum data rate, encryption status, AP MAC address, SSID, etc.) to all nearby clients. For example, the SSID identifies a particular wireless network. An acronym list of some terminologies used is presented here. 
     Acronym List 
     AP Access Point 
     A 1  Address  1   
     A 2  Address  2   
     A 3  Address  3   
     BSS Basic Service Set 
     BSSID Basic Service Set Identifier 
     DTIM Delivery Traffic Indication Map 
     IE Information Element 
     IEEE Institute of Electrical and Electronics Engineers 
     L2 Layer 2 
     MAC Media Access Control 
     OUI Organizationally Unique Identifier 
     P2P Peer-to-Peer 
     SNAP Subnetwork Access Protocol 
     SSID Service Set Identifier 
     STA Station 
     TDLS Tunneled Direct Link Setup 
     TSF Timing Synchronization Function 
     WFA WiFi Alliance 
     WFD WiFi Display 
     WiFi Wireless Fidelity 
     In one aspect, the wireless protocol IEEE 802.11z defines a protocol which allows wireless 802.11 stations (STAs) that are associated with the same Access Point (AP) to set up a direct link, e.g. a wireless peer-to-peer connection, between them. The protocol is referred to as Tunneled Direct Link Setup (TDLS). The TDLS setup messages are encapsulated in a specific Ethertype, so that they can be tunneled through any AP. In one example, the Ethertype is a field within an Ethernet frame which indicates the protocol encapsulated within the frame payload. This is useful in particular because APs do not have to be upgraded for TDLS to be used between two STAs. TDLS direct links can be set up between two TDLS capable STAs without need to upgrade the AP. 
     Currently, TDLS assumes that discovery of other STAs in the same Basic Service Set (BSS) (e.g. associated with the same AP) is based on detecting source and destination addresses and sending a TDLS setup request without prior knowledge of the intended peer STA&#39;s capabilities. However, it is desirable to have a more deterministic method of discovery&#39;, so that a list of potential peer STAs that are TDLS capable can be available before attempting a TDLS direct link setup. 
     Accordingly, referring to back to  FIG. 1 , in an aspect, the described apparatus and methods include a peer discovery component  108  at one or more stations, such as at clients  104  and  106 , to manage discovery of, and communication with, one or more other peer STAs. In an aspect, for example, peer discovery component  108  may be one or any combination of hardware, software, firmware, executable instructions, or data, executable to facilitate discovery of one or more peer STAs and initiate and/or establish setup of a TDLS direct link  109 . In an aspect, peer discovery component  108  may include a discovery request generator  110  configured to generate a discovery request  112  for information on potential peer STAs. For example, in an aspect, discovery request  112  may include a discovery request frame having a particular format, and the discovery request frame may be encapsulated for transparent transmission through another STA, such as access point  102 , as will be discussed in more detail below. Further, for example, in a different aspect, discovery request  112  may include or be appended to a probe request, or a beacon, transmitted as part of a Peer-to-Peer (P2P) discovery protocol. In this case, for example, discovery request  112  may include a TDLS capability indication, and optionally may include association information, as will be discussed in more detail below. 
     Moreover, peer discovery component  108  may additionally include a discovery response determiner  114  configured to determine if a discovery response  116  has been received. In an aspect, for example, discovery response  116  may include, or may provide an inference for determining a TDLS capability indication  118  of one or more peer STAs providing the discovery response  116 , e.g. a discovered station or stations. Such a discovered station may be considered a peer device. TDLS capability indication  118  may be used for identifying a TDLS capable STA, TDLS capabilities of the identified STA, and/or any other parameters for establishing a TDLS communication, e.g. TDLS direct link  109 , with the identified STA. 
     Additionally, peer discovery component  108  may additionally include a discovery response generator  120  configured to generate discovery response  116 , such as based upon receipt of discovery request  112  from another STA. In other words, STA  106  may operate discovery response generator  120  to generate discovery response  116  in reply to receiving discovery request  112  from STA  104 . Alternatively, or in addition, STA  104  may operate discovery response generator  120  to generate a second discovery response in reply to detecting or receiving a second discovery request from another device. 
     Moreover, peer discovery component  108  may further include a peer communication initiator  122  to establish communication with another peer STA. For example, in an aspect, peer communication initiator  122  is include protocols to initiate or to perform establishment of a TDLS communication with another STA based on STA information  118  received in discovery response  116 . 
     For example, in the case of  FIG. 1 , if STA  104  transmits discovery request  112  that is received by STA  106 , then STA  106  may generate discovery response  116  and transmit discovery response  116  for receipt by STA  104 . Based on TDLS capability indication  118 , STA  104  may then establish TDLS direct link  109  with STA  106 . 
     Thus, the apparatus and methods of the described aspects provide a deterministic method of discovery, so that a list of potential peer STAs that are TDLS capable can be available before attempting a TDLS direct link setup. 
     In one aspect, with the advent of new connection types for WiFi devices, such as Peer-to-Peer (P2P) and Tunneled Direct Link Setup (TDLS), there is a need for device and service discovery over multiple connection protocols. Discovery refers to a computer protocol that facilitates obtaining access to a wireless device or service. TDLS is defined in the IEEE 802.11z protocol. Peer-to-Peer (P2P) protocol is currently also referred to as Wireless Fidelity (WiFi) Alliance (WFA) Direct. TDLS and P2P may likely become transport mechanisms for WFA Display (WFD). WFD is a WFA certification label for wireless connections with a display. 
     Referring to  FIGS. 2 and 3 , in one aspect, peer discovery component  108  ( FIG. 1 ) may achieve discovery of potential TDLS peer devices by piggybacking TDLS discovery on P2P device discovery. P2P device discovery is based on a Probe Request/Probe Response exchange between the P2P devices on a so called social channel. For the purpose of TDLS peer STA discovery performed by peer discovery component  108  ( FIG. 1 ), discovery request  112  and/or discovery response  116  may include the Probe Request frame  130  and/or Probe Response frame  132  including respective TDLS capability indication  119 , corresponding to the requesting STA, and/or TDLS capability indication  118 , corresponding to the responding STA. 
     In one aspect, the respective TDLS capability indication  118  or  119  may be a portion of a capability element  134  or  136 , respectively. For example, where capability element  134  or  136  comprises Extended Capabilities element, the respective TDLS capability indication  118  or  119  may be a bit inside the Extended Capabilities element. Further, for example, the TDLS capability bit may be bit  37  of the Capabilities field of the Extended Capabilities element. In another example, the TDLS capability indication  118  or  119  may not be physically present, but may be inferred from a WFD capability indication  138  or  140  that is included in the Probe Request/Response frame  130 / 132 , if TDLS is a mandatory part of WFD certification. In yet another example, the TDLS capability indication  118  or  119  may be inferred from a separate TDLS capability element, e.g. a specific type of capability element  134  or  136 , which may be included in the Probe Request/Response frame  130 / 132 . 
     The Peer-to-Peer (P2P) discovery procedure may also yield the Basic Service Set Identifier (BSSID) of an AP with which the TDLS capable device is currently associated. In one aspect, Basic Service Set in the IEEE 802.11 protocol is comprised of one access point (AP) and all associated stations (STA). To this end, referring to  FIGS. 2 and 3 , the current BSSID  146  or  148 , corresponding to the requesting or the responding STA, respectively, may be included in the Probe Request/Response frames  130 / 132  transmitted as part of P2P discovery, in the form of a BSSID element  142  or  144 . 
     Referring to  FIG. 4 , an example of a BSSID element format  200 , such as for BSSID element  142  or  144  of  FIGS. 2 and 3 , includes the following:
         The Element ID field  202  identifies the BSSID element, as defined in Table 7-26 of 802.11-2007 protocol definition   The Length field  204  is set to 6   The BSSID field  206  is set to the MAC address of the AP to which the STA is currently associated       

     Other information about the current association may be included in the Probe Request/Response  130  or  132  by including an Association Element  150  or  152 . The Association Element  150  or  152  may contain information about a current association of the device (e.g., the respective STA) sending the Probe Request/Response frame  130  or  132 . 
     Referring to  FIG. 5 , an example of an Association Element format  300 , such as for association element  150  or  152  of  FIGS. 2 and 3 , includes the following:
         Element ID field  302  identifies the Association element, as defined in Table 7-26 of 802.11-2007 protocol definition   Length field  304  is set to 7+n   BSSID field  306  is set to the MAC address of the AP to which the STA is currently associated (It is noted the BSSID field  306  of association element format  300  may be the same as BSSID field  206  of BSSID element format  200  of  FIG. 4 )   Channel field  308  is set to the channel of the association   SSID field  310  is set to the SSID of the association. The Service Set Identifier, SSID, is the human readable name of the network.       

     In one aspect, a Service Set Identifier specifies a particular 802.11 wireless network, either local or enterprise. Adding a BSSID element  142 / 144  or an Association element  150 / 152  to the Probe Request/Response  130 / 132  may need to be defined at the WiFi Alliance (WFA), for example as part of the WFA TDLS specification, since regular 802.11 STAs do not send Probe Responses, and the Probe Requests are destined only for APs, e.g. AP  102  (not for other STAs, e.g. STA  104  or  106 ). In P2P mode, which is defined entirely within the WFA, STAs sending Probe Requests/Response frames to other STAs are part of the P2P discovery. The TDLS capability bit, e.g. as referred to above with regard to TDLS capability indication  118  or  119 , is to be defined by the Institute of Electrical and Electronics Engineers (IEEE) since the TDLS capability bit requires the definition of a bit inside a field that is controlled by the IEEE. 
     It should be understood that although capability element  134  and  136 , BSSID element  142  and  144 , and association element  150  and  152  are described with reference to probe request  130  and probe response  132 , respectively, these elements may also be present in discovery request  112  and discovery response  116  of  FIG. 1 . In other words, discovery request  112  and discovery response  116  of  FIG. 1  may include one or more of capability element  134  and  136 , BSSID element  142  and  144 , or association element  150  and  152  in a TDLS discovery process that is not associated with a P2P discovery process. 
     In one example, if a discovered STA, e.g. STA  106  of  FIG. 1 , indicates that it is currently associated with an AP, e.g. AP  102  of  FIG. 1 , and the scanning STA, e.g. STA  104  of  FIG. 1 , is capable of associating with that AP, the scanning STA may associate with the AP and form a TDLS direct link, e.g. link  109  of  FIG. 1 , with the discovered STA, rather than start a P2P network with the discovered STA. Advantages of forming a TDLS direct link  109  are that concurrent access with the AP is likely to be easier, and there is no need to enter new credentials, in order to connect to the discovered STA (because the credentials for the AP were available at the scanning STA). 
     In one aspect, a scanning STA that wants to connect to a discovered STA which is associated with an AP has two options. A first option is to start a P2P network with the discovered STA. The P2P network may be started on the same channel as is used for the association with the AP, to simplify concurrent operation by the discovered STA. A second option is that the scanning STA associates to the AP and then sets up a TDLS direct link with the discovered STA. When the scanning STA has credentials for the AP, this process will require no user interaction. When the scanning STA does not have security credentials for the AP, this process will include the user/STA associating with the AP, either by entering the security credentials, or by push-button configuration, etc. One skilled in the art would understand that many techniques for establishing security credentials can be used without affecting the spirit or scope of the present disclosure. 
     In another aspect, if the scanning STA is currently associated with the same AP as the discovered STA, the scanning STA may be able to communicate through the AP (since most APs allow their associated STAs to communicate peer-to-peer). In one aspect, whether direct STA-to-STA communication is possible can be tested by sending a TDLS discovery frame, e.g. discovery request  112  of  FIG. 1 , to the discovered STA, through the AP. For example, the discovered STA sends a TDLS discovery response, e.g. discovery response  116  of  FIG. 1 , when it receives the discovery request. In one example, peer discovery component  108  of the scanning STA of  FIG. 1  may maintain a timer corresponding to the transmission of discovery request  112 , and when a response timeout occurs, e.g. when the timer expires, the scanning STA assumes that STA-to-STA communications are blocked by the AP. In another aspect, the type of security of the link  109  between the STA and the AP may be indicated in the Association Element, e.g. in association element  150  or  152  in  FIGS. 2 and 3 . 
     Referring to  FIGS. 6 and 7 , in one aspect, peer discovery component  108  ( FIG. 1 ) may be configured to generate and transmit encapsulated discovery request  160  and/or encapsulated discovery response  162 . For example, encapsulated discovery request  160  and encapsulated discovery response  162  correspond to discovery request  112  and discovery response  116 , respectively, each contained within an encapsulation  164  and  166 , respectively. For example, in an aspect, encapsulation  164  and  166  may be a message or frame format that allows discovery request  112  and discovery response  116  to be transparently transmitted through another STA, such as through access point  102  of  FIG. 1 . For instance, encapsulation  164  and  166  may include, but is not limited to a layer 2 (L2) encapsulation. Accordingly, encapsulated discovery request  160  and encapsulated discovery response  162  define two new TDLS frames for the purpose of TDLS discovery. 
     In one aspect, the encapsulated TDLS discovery request/response frames  160  and  162  may include at least a respective Basic Service Set Identifier (BSSID) element  168  and  170 , which identifies a respective BSSID  172  and  174  of the Media Access Control (MAC) address of the AP to which the STA sending the TDLS discovery request frame  160  or discovery response frame  162  is associated. It is noted that BSSID element  168  and  170  may have the same format as BSSID element format  200  of  FIG. 4 , and/or may be the same as BSSID elements  142  and  144  of  FIGS. 2 and 3 , respectively. 
       FIG. 8  illustrates an example of encapsulated TDLS discovery request frame format  500 , such as may be used for encapsulated TDLS discovery request frame  160 , including Basic Service Set Identifier (BSSID) element  168 . Further, encapsulated TDLS discovery request frame format  500  may include various other information elements  504 , as described at  506 , and which may be ordered as indicated at  502 . And,  FIG. 9  illustrates an example TDLS discovery response frame format  600 , such as may be used for encapsulated TDLS discovery response frame  162 , including Basic Service Set Identifier (BSSID) element  170 . Further, encapsulated TDLS discovery response frame format  600  may include various other information elements  604 , as described at  606 , and which may be ordered as indicated at  602 . 
     Referring back to  FIGS. 6 and 7 , instead of respective BSSID elements  168  and  170 , the existing Link Identifier element  176  and  178  as defined in 802.11z may be respectively included in the encapsulated TDLS discovery request and response frames  160  and  162 . 
       FIG. 10  illustrates an example of a Link Identifier element format  700 , such as may be used for Link Identifier element  176  and  178  of  FIGS. 6 and 7 , with the following definitions: element ID  702  that identifies the link identifier element; length field  704  that identifies a length, e.g. which may be set to be 18; and address fields  705 , such as but not limited to, a BSSID field  706  (which may be the same as or similar to previously discussed BSSID fields), a TDLS initiator STA Address field  708 , and a TDLS responder STA address  710 , which may be set depending on whether the element is included in a discovery request or in a discovery response. 
       FIG. 11  is a table  800  that includes example contents  802  and  804  of Link Identifier address fields  705  included in encapsulated discovery request frame  160  and encapsulated discovery response frame  164  of  FIGS. 6 and 7 . 
       FIG. 12  illustrates an example TDLS discovery request frame format  900 , such as may be used for encapsulated discovery request frame  160  of  FIG. 6 , including Link Identifier element  176 . Further, encapsulated TDLS discovery request frame format  900  may include various other information elements  904 , as described at  906 , and which may be ordered as indicated at  902 . 
     Also,  FIG. 13  illustrates an example TDLS discovery response frame format  1000 , such as may be used for encapsulated discovery response frame  162  of  FIG. 7 , including a Link Identifier element  178 . Further, encapsulated TDLS discovery response frame format  1000  may include various other information elements  1004 , as described at  1006 , and which may be ordered as indicated at  1002 . 
     Referring back to  FIGS. 6 and 7 , in one aspect, encapsulated discovery request frame  160  and encapsulated discovery response frame  162  each may include a respective association element  180  and  182 , which includes other information regarding a current association of the respective STA. For example, association element  180  and  182  may include information such as, but not limited to, the type of security (e.g. security type) on the link with the AP, the operating channel, the operating channel bandwidth, the current PHY rate from the AP, the current PHY rate to the AP, etc. It is noted that association element  180  and  182  may be the same as, or similar to, association element  150  and  152  of  FIGS. 2 and 3 . 
       FIG. 14  illustrates an example of an Association Element format  1100 , which contains information about the current association of a device. For example, association element format  1100  may include one or more information elements  1101  including, but not limited to, one or more of an element ID field  1102 , a length field  1104 , a BSSID field  1106  (which may be the same as or similar to the previously discussed BSSID fields), a STA address field  1108 , a type of security field  1110 , an operating channel field  1112 , an operating bandwidth field  1114 , a PHY rate to AP field  1116 , a PHY rate from AP field  1118 , and an SSID field  1120 . 
     In one aspect, information elements  1101  that are related to device type discovery or service discovery (including vendor specific elements) are added to the discovery frames. The TDLS discovery request/response frames  160  and  162  ( FIGS. 6 and 7 ) may include some or all of the information elements  1101  that would typically be included in a Probe Request/Response frame as transmitted by a STA. STAs only transmit Probe Response frames when they operate as a P2P device. 
     In one aspect, the TDLS discovery request frame  160  ( FIG. 6 ) is transmitted to a broadcast address, so that any device in the network layer 2 domain can receive it. Devices in the same network layer 2 domain could be devices associated with the AP, but also devices connected through the wired interface of the AP and wireless devices that are associated with another AP. 
     In another aspect, STAs that receive a TDLS discovery request frame  160  ( FIG. 6 ) and are TDLS capable may respond with the TDLS discovery response frame  162  ( FIG. 7 ). A TDLS discovery response frame  162  may not be transmitted when the BSSID  172  (or, another BSSID value from one of the other elements that may be included in discovery request  160 ) indicated in the TDLS discovery request frame  160  does not match its own BSSID  174  (or, another BSSID value from one of the other elements that associated with discovery response  160  or the responding STA). The 802.11z protocol currently does not allow a TDLS direct link  109  ( FIG. 1 ) to be set up between STAs that are associated with different BSSIDs. Thus, referring back to  FIG. 6 , the TDLS discovery request  160  may include an indication  184  of whether a response should be sent or not in case of a non-matching BSSID. 
     In another aspect, the channel  1012  of the current association is included in the TDLS discovery request/response  160  or  162 . When the channels are the same, this indicates that the STAs can set up a TDLS direct link  109  ( FIG. 1 ) even when the BSSIDs, e.g.  172  and  174 , are different. In another aspect, the TDLS discovery request frame is sent immediately after associating with an AP. The TDLS discovery request frame may be sent at regular intervals, for instance, once per minute. The TDLS discovery request frame may be sent to a unicast address. A TDLS discovery request frame may be sent to a unicast address (A 1 =BSSID, A 2 =STA address, A 3 =unicast address). The unicast address to which a TDLS discovery request frame is transmitted may be obtained after a MAC Service Data Unit (MSDU) has been transmitted to or received from this address. 
     In another aspect, the TDLS capability indication  118  or  119  ( FIG. 1 ) is implied by receiving a TDLS discovery request frame  160  or response frame  162 . But, similar to the disclosure above with respect to  FIGS. 2 and 3 , a specific TDLS capability element, e.g. capability element  134  or  136 , may be included in the TDLS discovery request/response  112 / 116 , including the encapsulated TDLS discovery request/response  160 / 162 . For example, the TDLS capability may be signaled as part of an Extended Capability element that is included in the TDLS discovery request/response. 
     In another aspect, information elements that are contained in the TDLS setup request/response frames are also contained in the TDLS discovery request/response frames. For the purpose of discovery, in one example, the TDLS setup rules are modified as follows: A TDLS setup request frame is transmitted to the Broadcast address, which designates the frame as a discovery frame (e.g. the transmitting of a TDLS setup request frame to a group address designates the setup request frame as a discovery frame). When receiving a broadcast TDLS setup request frame, a device that supports TDLS responds with a unicast TDLS setup response frame. In an aspect, a TDLS setup confirm frame may not be transmitted in response to a received TDLS setup response frame that responded to the broadcast TDLS setup request frame. Setup requests and corresponding responses can be matched using a dialog token, e.g. a token used to identify messages relating to the same dialog or message exchange. Reusing the TDLS setup frames for discovery eliminates the need to define new frames within the 802.11z protocol. 
     When the TDLS setup request frame is used for TDLS discovery, the start of a direct link may be initiated by sending a TDLS setup confirm frame (in which case the confirm frame is the only frame needed to start the direct link). Either STA (either requester or responder) may transmit a TDLS setup confirm frame in order to activate the TDLS direct link. However, a TDLS setup confirm frame does not have to be transmitted between two TDLS-capable STAs after TDLS discovery, because the TDLS STAs may never actually exchange any data. In one aspect, the state for all received broadcast TDLS setup requests and associated TDLS setup responses are stored at the STAs. 
     Accordingly, when the TDLS setup request and the TDLS setup response frames are used for discovery, it may be necessary to send another TDLS setup request frame (and possibly a corresponding TDLS setup response frame and a TDLS setup confirm frame) to actually set up a direct link. This reduces the burden of having to keep track of the capabilities of all STAs from which a received a TDLS setup request/response frame was received that was part of a TDLS discovery exchange. 
     Further, in an aspect, potential TDLS peer STAs can be discovered by sending a broadcast discovery request, wherein the discovery request information is encapsulated in a layer 2 (L2) encapsulation. Additionally, for example, in one aspect, the discovery responses are sent to the unicast address of the requesting STA, wherein the discovery information is also encapsulated in the L2 encapsulation. 
       FIG. 15  illustrates an example flow diagram of a TDLS discovery exchange  400 . In the example, TDLS discovery exchange  400  is based on the newly defined TDLS discovery and response frames  160  and  162  ( FIGS. 6 and 7 ). At  401 , STA 1   104  transmits a broadcast TDLS discovery request frame  408  to the AP  102 , including address information A 1 =BSSID, A 2 =STA 1 , and A 3 =Broadcast. At  403  and  405 , the AP  102  forwards the TDLS discovery request frame  410  to the broadcast address, e.g. A 1 =Broadcast, A 2 =BSSID, A 3 =STA 1 . STA 2   106  receives the broadcast TDLS discovery request frame  410  from the AP  102 . STA 2   106  is TDLS capable and, at  407 , responds with a TDLS discovery response frame  412 , with address information A 1 =BSSID, A 2 =STA 2 , A 3 =STA 1 . In other words, STA 2   106  includes in the response frame  412  at least its current BSSID, and possibly other information regarding its current association or its capabilities (such as a device type or a device type element). At  409 , the AP  102  forwards the response frame  414  to STA 1   104 , with address information A 1 =STA 1 , A 2 =BSSID, A 3 =STA 2 . The response frame  414  is received by STA 1 , which subsequently adds STA 2   106  to the list of TDLS capable peer STAs. The BSSID included inside the payload of the TDLS discovery response  414  is the same as the BSSID to which STA 1   104  is associated. 
       FIG. 16  illustrates an example flow diagram of a TDLS discovery message flow  1200  based on a broadcast TDLS setup request, followed by a TDLS setup that starts with a unicast TDLS setup request. At  1201 , STA 1   104  transmits a broadcast TDLS setup request frame  1208  to the AP  102 , including address information A 1 =BSSID, A 2 =STA 1 , and A 3 =Broadcast. At  1203  and  1205 , the AP  102  forwards the TDLS setup request frame  1210  to the broadcast address, e.g. A 1 =Broadcast, A 2 =BSSID, A 3 =STA 1 . STA 2   106  receives the broadcast TDLS setup request frame  1210  from the AP  102 . STA 2   106  is TDLS capable and, at  1207 , responds with a TDLS setup response frame  1212 , with address information A 1 =BSSID, A 2 =STA 2 , A 3 =STA 1 . At  1209 , the AP  102  forwards the setup response frame  1214  to STA 1   104 , with address information A 1 =STA 1 , A 2 =BSSID, A 3 =STA 2 . The setup response frame  1214  is received by STA 1 . 
     At  1211 , STA 1   104  transmits a unicast TDLS setup request frame  1216  to the AP  102 , including address information A 1 =BSSID, A 2 =STA 1 , and A 3 =STA 2 , based on the TDLS response frame  1214  received at  1209 . At  1213 , the AP  102  forwards the TDLS setup request frame  1218  to the unicast address, e.g. A 1 =STA 2 , A 2 =BSSID, A 3 =STA 1 . STA 2   106  receives the unicast TDLS setup request frame  1218  from the AP  102 . At  1215 , STA 2   106  responds with a TDLS setup response frame  1220 , with address information A 1 =BSSID, A 2 =STA 2 , A 3 =STA 1 . At  1217 , the AP  102  forwards the setup response frame  1222  to STA 1   104 , with address information A 1 =STA 1 , A 2 =BSSID, A 3 =STA 2 . The setup response frame  1222  is received by STA 1 , and at  1219  STA 1  transmits a TDLS setup confirm frame  1224 , with unicast address A 1 =BSSID, A 2 =STA 1 , A 3 =STA 2 . At  1221 , AP  102  forwards setup response frame  1224 , with address A 1 =STA 2  , A 2 =BSSID, A 3 =STA 1 , to STA 2  for setting up a TDLS link. 
     In one aspect, a TDLS setup request frame that is received from a broadcast or multicast address may be interpreted as part of a TDLS discovery exchange, which implies that the information elements contained in it do not have to be stored at the receiver(s), except temporarily for the purpose of generating the corresponding TDLS setup response frame. In another aspect, to further indicate that the TDLS setup request frame is part of a discovery exchange and not part of a setup exchange, a TDLS discovery element may be included in the TDLS setup request frame, or a predefined Dialog Token value may be used in the TDLS setup request frame. 
     In another aspect, the TDLS discovery frames may include one or more device type elements that indicate a primary and/or secondary purpose of the device. Examples of device types include, but are not limited to, computer, input device (e.g., mouse, keyboard, etc.), display, camera, smartphone, etc. A TDLS discovery response may be transmitted only when a requested device type as present in the discovery request matches the device type at the receiving STA. 
     In one example, the determination of which information elements are included in a TDLS Setup Request frame and a TDLS Setup Response frame may be by whether they are used for TDLS discovery or used for TDLS link setup. In one aspect, for TDLS discovery, a Probe Request frame may be encapsulated in the TDLS Ethertype, and transmitted to the broadcast address or a unicast address. In addition to the regular information elements, the Probe Request may contain a Link Identifier, which specifies the MAC address of the transmitter STA and the BSSID. Other association parameters may be included also, such as the channel of the association, the current PHY rate from the AP, the type of security on the link with the AP, etc. The received Probe Responses will indicate whether the STA is TDLS capable through the Extended Capability element, or the TDLS capability may be inferred because the STA was able to parse the encapsulated Probe Request and respond with an encapsulated Probe Response. The Probe Response may contain a Link Identifier element that contains the TDLS initiator STA address, the BSSID of the TDLS responder STA, and the TDLS responder STA address. In one example, the Probe Response is encapsulated in a TDLS frame. One skilled in the art would understand that the association parameters listed herein are not exclusive and that others not mentioned herein may be included without affecting the scope or spirit of the present disclosure. 
       FIG. 17  is a table  1300  including examples of possible frames  1302  used in a TDLS discovery, e.g. a TDLS discovery request  1304  or a TDLS discovery response  1306 . In one example, all the frames use the TDLS encapsulation, or any other L2 encapsulation based on a proprietary Subnetwork Access Protocol Organizationally Unique Identifier (SNAP OUI), a proprietary. Ethertype with SNAP OUI 000000h, or any encapsulation layer on top of an Ethertype. SNAP is a 802.11 protocol for extending the Service Access Point field to specify more protocols. In one aspect, the Discovery Request is sent to the broadcast address (e.g., unicast to the AP, then broadcast by the AP), and the Discovery Response is sent to the unicast source address of the STA that transmitted the Discovery Request. In one example, two new TDLS frames, e.g. the encapsulated TDLS discovery request and response frames  160  and  162  ( FIGS. 6 and 7 ), are defined. 
     As previously discussed, both of these frames may contain an information element that identifies the STA transmitting the frame and it&#39;s BSSID. Other elements may be included as well. In one example, a TDLS Discovery Request is transmitted to the broadcast address after association to an AP. The received TDLS Discovery Response is then stored in a list of TDLS capable peer STAs. Information from the TDLS Discovery Request may also be stored in this list. In one example, a TDLS direct link is set up when traffic is exchanged with STAs in this list, or when a WiFi Display (WFD) link is set up with one of the STAs in this list. 
     TDLS direct links may be set up with multiple STAs in one setup, for example, by sending a broadcast TDLS Setup Request frame, receiving one or more TDLS Setup Response frames, and responding with a TDLS Setup Confirm frame to STAs with which a TDLS Direct Link should be set up. This may include all the STAs that sent a TDLS Setup Response. Group-wise TDLS direct link setup may combine TDLS discovery with TDLS link setup. 
     TDLS discovery through the AP does not yield information about the current distance between the potential peer STAs, which requires a frame exchange directly between the STAs. in a direct frame exchange, it is not known when the other STA is in the “awake” state because the other STA maybe in a power save mode and not awake. Thus, to circumvent this issue, the TDLS discovery request frame may indicate that the TDLS discovery response frame may be transmitted directly to the requesting STA. 
       FIG. 18  illustrates an example flow diagram  1400  showing a Broadcast discovery request with a direct discovery response. At  1401 , STA 1   104  transmits a broadcast. TDLS discovery request frame  1408  to the AP  102 , including address information A 1 =BSSID, A 2 =STA 1 , and A 3 =Broadcast. 
     The requesting STA, e.g. STA 1 , stays in active mode for some time after sending the request. The duration of the awake time may be indicated inside the request frame, for instance with reference to the Timing Synchronization Function (TSF). In one aspect, the TSF is a timing synchronization messaging system where each participating STA exchanges beacon frames. A start time of the awake time may be indicated as well. STAs that are associated with the same AP share the same timing reference, or TSF. When the indicated awake time has expired, the responding STA can send a discovery response through the AP, or it may send no response at all. When the response is sent through the AP, the STA sending the response may include an indication why it was unable to send the response directly. The requesting STA may in this case follow up with a unicast discovery request. 
     At  1403  and  1405 , the AP  102  forwards the TDLS discovery request frame  1410  to the broadcast address, e.g. A 1 =Broadcast, A 2 =BSSID, A 3 =STA 1 . STA 2   106  receives the broadcast TDLS discovery request frame  1410  from the AP  102 . STA 2   106  is TDLS capable. 
     At  1407 , STA 2  responds with a direct transmission of TDLS discovery response frame  1412 , with address information A 1 =BSSID, A 2 =STA 2 , A 3 =STA 1 , and optionally with a direct transmission indicator information element  1414 , such as a public action type, to STA 1 . The response frame  1412  is received by STA 1 , which subsequently adds STA 2   106  to the list of TDLS capable peer STAs. 
     In one example, a direct response  1412  is sent only when the requesting STA is associated with the same BSSID or when it is associated on the same channel. Otherwise, the response may be sent through the AP. In one example, a direct response is retried only for a limited number of time since the requesting STA may not be reachable directly. The direct response may include channel sounding information and/or transmit power information. The direct response may also include other information elements, for example, which specify the capabilities at the responding STA. 
     In one example, the TDLS discovery request frame  1412  includes direct transmission indicator information element  1414  that indicates if the response frame must be transmitted through the AP or through a direct path. In one aspect, the TDLS discovery response frame  1412  transmitted over the direct path is a management frame of subtype Public Action. Public Action frames (as defined in IEEE P802.11 rev mb) are received by STAs also when no association or direct link exists between the sender and the receiver of the frame. Hence, the designation “public”. A scanning STA may transmit multiple broadcast TDLS discovery request frames, e.g.  1408 , to increase the probability that STAs which skip Delivery Traffic Indication Map (DTIM) beacons may receive them. Some STAs skip the DTIM beacons to increase sleep time and reduce the standby power consumption. 
     In one example, the STA transmits a broadcast TDLS discovery request frame  1408  after association or after a refresh option, to provide a recent list of nearby devices that had been selected at the STA. The received TDLS discovery response frame  1412  indicates which STAs can be reached through the AP, or which STAs are actually nearby, when the response is sent directly. 
       FIG. 19  illustrates an example of a message exchange  1500  including a Unicast discovery request to one or more selected target STAs, with a direct response. In one example, the target STAs are selected from a list obtained after receiving a discovery response through the AP based on a previously transmitted broadcast discovery request. At  1501 , STA 1   104  transmits a unicast TDLS discovery request frame  1508  to the AP  102 , including address information A 1 =BSSID, A 2 =STA 1 , and A 3 =STA 2 , thereby directing a unicast message to STA 2 . At  1503 , the AP  102  forwards the TDLS discovery request frame  1510  to the unicast address, e.g. A 1 =STA 2 , A 2 =BSSID, A 3 =STA 1 , thereby unicasting the message to STA 2 . STA 2   106  receives the unicast TDLS discovery request frame  1510  from the AP  102 . STA 2   106  is TDLS capable, for example, as noted above based on a prior discovery response. Accordingly, at  1505 , STA 2  responds with a direct transmission of TDLS discovery response frame  1512 , with address information A 1 =STA 1 , A 2 =STA 2 , A 3 =BSSID, and optionally with a direct transmission indicator information element  1414 , such as a public action type as discussed above, to STA 1 . The response frame  1512  is received by STA 1 . 
       FIG. 20  illustrates an exemplary message flow  1600  including a TDLS broadcast discovery with a response through the AP combined with unicast discovery with a direct response. The TDLS discovery procedure may be based on existing Probe Request and Probe Request frames, for example, in the following way. At  1601 , the TDLS Discovery Request frame  1608  encapsulates a Probe Request frame body, which is sent to the Broadcast address via the AP  102 . At  1603  and  1605 , AP  102  forwards the TDLS Discovery Request frame  1610 , e.g. based on  1608  but with a revised address. At  1607  and  1609 , the TDLS Discovery Response frame  1612  is a plain Probe Response frame, without additional encapsulation. TDLS Discovery Request frame  1608  with the Probe Request frame body and TDLS Discovery Response frame  1612  with Probe Response frame may contain a BSSID element that specifies the BSSID and the address of the STA sending the TDLS Discovery Request frame, and optionally a Channel element that indicates the channel on which the STA is currently associated with an AP. The TDLS capability is signaled by setting the appropriate capability bit in the Extended Capability element contained in the Probe Request and Probe Response frame bodies. The Probe Response may include the BSSID in the A 3  field or the STA 2  address. 
     At  1611 , STA 1   104  transmits a unicast TDLS discovery request frame  1616  to the AP  102 , including address information A 1 =BSSID, A 2 =STA 1 , and A 3 =STA 2 , thereby directing a unicast message to STA 2 . At  1613 , the AP  102  forwards the TDLS discovery request frame  1618  with new addressing, e.g. the unicast address, A 1 =STA 2 , A 2 =BSSID, A 3 =STA 1 , thereby unicasting the message to STA 2 . STA 2   106  receives the unicast TDLS discovery request frame  1618  from the AP  102 . STA 2   106  is TDLS capable, for example, as noted above based on the prior discovery response. Accordingly, at  1615 , STA 2  responds with a direct transmission of TDLS discovery response frame  1620 , with address information A 1 =STA 1 , A 2 =STA 2 , A 3 =BSSID to STA 1 . The response frame  1620  is received by STA 1 . 
     Referring to  FIGS. 21 and 22 , example message flows  1700  and  1800  are illustrated for the TDLS discovery procedure based on Probe Request and Probe Response, respectively. An exemplary Probe Request frame body is defined in IEEE 802.11-2007, clause 7.2.3.8, and in WiFi_P2P_Technical_Specification_v1.00.pdf, clause 4.2.2. An exemplary Probe Request frame body is defined in IEEE 802.11-2007, clause 7.2.3.9, and in WiFi_P2P_Technical_Specification_v1.00.pdf, clause 4.2.3. 
     In  FIG. 21 , at  1701 , the TDLS Discovery Request frame  1708  encapsulates a Probe Request frame body, to STA 1  which is sent to the Broadcast address via the AP  102 . At  1703  and  1705 , AP  102  forwards the TDLS Discovery Request frame  1710 , e.g. based on  1708  but with a revised address information A 1 =STA 1 , A 2 =STA 2 , A 3 =BSSID to STA 1 . At  1707 , STA 2  directly transmits to STA 1 , e.g. over a wireless communication link that does not include AP  102 , a TDLS discovery response  1712 , such as a Probe Response frame body with address information A 1 =STA 1 , A 2 =STA 2 , A 3 =BSSID. 
     In  FIG. 22 , at  1801 , the TDLS Discovery Request frame  1808  encapsulates a Probe Request frame body, which is sent to the Broadcast address via the AP  102 . At  1803  and  1805 , AP  102  forwards the TDLS Discovery Request frame  1810 , e.g. based on  1808  but with a revised address. At  1807 , STA 2  directly transmits a probe response  1812 , with address information A 1 =STA 1 , A 2 =STA 2 , A 3 =STA 2 , to STA 1 . 
     Referring to  FIG. 23 , a message flow diagram  1900  illustrates a method of an AP facilitating P2P discovery by echoing received Probe Requests after the Delivery Traffic Indication Map (DTIM) Target Beacon Transmission Time (TBTT). The contents of the Probe Request frame may be copied without changes, including the address fields. Broadcast traffic is transmitted after the DTIM beacon when one or more STAs associated with the AP are in power save mode, which allows for P2P capable STAs to enter a power save mode while they remain discoverable by scanning P2P devices. At  1901  and  1903 , STA 1  transmits Probe Request frames  1908  with address information A 1 =Broadcast, A 2 =STA 1 , A 3 =a wildcard BSSID. As used herein, a “wildcard BSSID” refers to a generic BSSID used to represent all BSSIDs. In other words, the wildcard BSSID is somewhat like a broadcast address. For example, any device that receives a Probe Request with a wildcard BSSID will send a probe response, because the wildcard BSSID in the Probe Request matches the BSSID associated with the device. 
     After sending Probe Request frame  1908 , the scanning P2P device, e.g. STA 1   102 , should remain listening on the channel until at least some time after the DTIM TBTTs  1914  of the APs on the channel, or for a time that typically is the time between DTIM beacons. At  1903  and  1905 , AP  102  echoes the Probe Request frame  1908  to all STAs, e.g. STA 1  and STA 2 , a time period after the DTIM TBTTs  1914  of the AP. The AP forwarding received Probe Requests  1908  (in particular those with P2P related information elements) thereby allows P2P capable devices, e.g. STA 1 , to enter a power save mode once associated, while they remain discoverable by other P2P devices based on the echoed Probe Requests. An AP that forwards received (P2P) Probe Requests  1908  should indicate this power save mode related information or echoing information to the associated STAs (for instance by setting a capability bit). Further, at  1909 , STA 2  may directly transmit Probe Response  1912 , with address information A 1 =STA 1 , A 2 =STA 2 , A 3 =STA 2 , to STA 1  in order to initiate establishment of communication. 
     Referring to  FIG. 24 , based on the foregoing descriptions, in an aspect, a method  2400  for performing peer device discovery in a communication network includes generating a discovery request configured to identify a Tunneled Direct Link Setup (TDLS) capable peer device (Block  2402 ). Further, method  2400  includes transmitting the discovery request (Block  2404 ). Additionally, method  2400  includes determining if a discovery response is received in response to the discovery request (Block  2406 ). 
     In an aspect of method  2400 , the generating the discovery request (Block  2402 ) may further include encapsulating the discovery request in a data frame (Block  2403 ). For example, the encapsulating enables the discovery request to be transparent to an access point. Accordingly, the transmitting (Block  2404 ) may further include transmitting to the access point (Block  2405 ). For example, the access point may then forward the discovery request on to other stations associated with the access point, wherein the encapsulating allows for the access point to forward the discovery request even if the access point is not configured to understand the discovery request. 
     In another aspect of method  2400 , the generating the discovery request (Block  2402 ) may further include appending a TDLS capability information to a probe request or to a beacon (Block  2407 ). For example, the probe request or the beacon may be based on P2P discovery. Accordingly, the transmitting (Block  2404 ) may further include transmitting the probe request or beacon including the TDLS capability information (Block  2409 ). Additionally, the determining if a discovery response is received (Block  2406 ) may also include receiving the discovery response including a TDLS capability information appended to a probe response (Block  2411 ). 
     Referring to  FIG. 25 , in one aspect, any of the illustrated stations STAs, e.g. STAs  102 ,  104 , and/or  106  of  FIG. 1 , may be represented by station  2000 . Station  2000  includes a processor  2001  for carrying out processing functions associated with one or more of components and functions described herein. Processor  2001  can include a single or multiple set of processors or multi-core processors. Moreover, processor  2001  can be implemented as an integrated processing system and/or a distributed processing system. 
     Station  2000  further includes a memory  2002 , such as for storing local versions of applications being executed by processor  2001 . Memory  2002  can include any type of memory usable by a computer, such as random access memory (RAM), read only memory (ROM), tapes, magnetic discs, optical discs, volatile memory, non-volatile memory, and any combination thereof. 
     Further, station  2000  includes a communications component  2003  that provides for establishing and maintaining communications with one or more parties utilizing hardware, software, and services as described herein. Communications component  2003  may carry communications between components on station  2000 , as well as between station  2000  and external devices, such as devices located across a communications network and/or devices serially or locally connected to station  2000 . For example, communications component  2000  may include one or more buses, and may further include transmit chain components and receive chain components associated with a transmitter and receiver, respectively, operable for interfacing with external devices. 
     Additionally, station  2000  may further include a data store  2004 , which can be any suitable combination of hardware and/or software, that provides for mass storage of information, databases, and programs employed in connection with aspects described herein. For example, data store  2004  may be a data repository for applications not currently being executed by processor  2001 . 
     Station  2000  may additionally include a user interface component  2005  operable to receive inputs from a user of station  2000 , and further operable to generate outputs for presentation to the user. User interface component  2005  may include one or more input devices, including but not limited to a keyboard, a number pad, a mouse, a touch-sensitive display, a navigation key, a function key, a microphone, a voice recognition component, any other mechanism capable of receiving an input from a user, or any combination thereof. Further, user interface component  2005  may include one or more output devices, including but not limited to a display, a speaker, a haptic feedback mechanism, a printer, any other mechanism capable of presenting an output to a user, or any combination thereof. 
     Additionally, in some aspects, station  2000  may include peer discovery component  108  configured to discovery and initiate or establish a TDLS communication with another peer device, such as another station. Peer discovery component  108  includes all or some portion of the functionality described above, such as with regard to  FIG. 1  as well as the other various aspects described with regard to the various message flow diagrams included herein. For example,  FIGS. 4, 12, and 14-19  illustrate various implementations for generating such discovery requests and for determining such discovery responses. 
     Referring to  FIG. 26 , based on the foregoing descriptions, an apparatus  2600  for performing Tunneled Direct Link Setup (TDLS) discovery in a wireless communication network may reside at least partially within a station, such as an access point and/or a client or mobile node. For example, apparatus  2600  may include, or be a portion of, stations  102 ,  104  and  106  of  FIG. 1 . It is to be appreciated that apparatus  2600  is represented as including functional blocks, which can be functional blocks that represent functions implemented by a processor, software, or combination thereof (e.g., firmware). Apparatus  2600  includes a logical grouping  2602  of electrical components that can act in conjunction. For instance, logical grouping  2602  can include means for generating a discovery request configured to identify a Tunneled Direct Link Setup (TDLS) capable peer device  2604 . For example, referring to  FIG. 1 , means for generating discovery request  2604  may include peer discovery component  108  and/or discovery request generator  110 . Alternatively, or in addition, referring to  FIG. 25 , means for generating discovery request  2604  may include processor  2001 . Further, logical grouping  2602  can include means for transmitting the discovery request  2606 . For example, referring to  FIG. 1 , means for transmitting the discovery request  2606  may include peer discovery component  108  and/or discovery request generator  110 . Alternatively, or in addition, referring to  FIG. 25 , means for transmitting the discovery request  2606  may include processor  2001  and/or communications component  2003 , or a portion thereof, such as a transmitter. Additionally, logical grouping  2602  can include means for determining if a discovery response is received in response to the discovery request  2608 . For example, referring to  FIG. 1 , means for determining receipt of discovery response  2608  may include peer discovery component  108  and/or discovery response determiner  114 . Alternatively, or in addition, referring to  FIG. 25 , means for determining receipt of discovery response  2608  may include processor  2001  and/or communications component  2003 , or a portion thereof, such as a receiver. 
     In an aspect of apparatus  2600 , the means for generating the discovery request  2604  may further include means for encapsulating the discovery request in a data frame  2605 . For example, encapsulating enables the discovery request to be transparent to an access point. For example, referring to  FIG. 1 , means for encapsulating the discovery request in a data frame  2605  may include peer discovery component  108  and/or discovery request generator  110 . Alternatively, or in addition, referring to  FIG. 25 , means encapsulating the discovery request in a data frame  2605  may include processor  2001 . Accordingly, the means for transmitting  2606  may further include means for transmitting to the access point  2607 . For example, the access point may then forward the discovery request on to other stations associated with the access point, wherein the encapsulating allows for the access point to forward the discovery request even if the access point is not configured to understand the discovery request. 
     In another aspect of apparatus  2600 , the means for generating the discovery request  2604  may further include means for appending a TDLS capability information to a probe request or to a beacon  2609 . For example, the probe request or the beacon may be based on P2P discovery. For example, referring to  FIG. 1 , means for appending TDLS capability information to a probe request or to a beacon  2609  may include peer discovery component  108  and/or discovery request generator  110 . Alternatively, or in addition, referring to  FIG. 25 , means for appending TDLS capability information to a probe request or to a beacon  2609  may include processor  2001 . Accordingly, the means for transmitting  2606  may further include means for transmitting the probe request or beacon including the TDLS capability information  2611 . Additionally, the means for determining if a discovery response is received  2608  may also include means for receiving the discovery response including a TDLS capability information appended to a probe response  2613 . 
     In an aspect, apparatus  2600  may include at least one processor or one or more modules of a processor operable to perform the means described above. 
     Additionally, apparatus  2600  may include a memory  2616  that retains instructions for executing functions associated with electrical components  2604 ,  2606 , and optionally  2608 , and  2605 ,  2607 ,  2609 ,  2611 , and  2613 . While shown as being external to memory  2616 , it is to be understood that one or more of electrical components  2604 ,  2606 , and optionally  2608 , and  2605 ,  2607 ,  2609 ,  2611 , and  2613 , may exist within memory  2616 . For example, in an aspect, memory  2616  may include memory  2002  and/or data store  2004  of  FIG. 25 . 
     As used in this application, the terms “component,” “module,” “system” and the like are intended to include a computer-related entity, such as but not limited to hardware, firmware, a combination of hardware and software, software, or software in execution. For example, a component may be, but is not limited to being, a process running on a processor, a processor, an object, an executable, a thread of execution, a program, and/or a computer. By way of illustration, both an application running on a computing device and the computing device can be a component. One or more components can reside within a process and/or thread of execution and a component may be localized on one computer and/or distributed between two or more computers. In addition, these components can execute from various computer readable media having various data structures stored thereon. The components may communicate by way of local and/or remote processes such as in accordance with a signal having one or more data packets, such as data from one component interacting with another component in a local system, distributed system, and/or across a network such as the Internet with other systems by way of the signal. 
     Furthermore, various aspects are described herein in connection with a terminal, which can be a wired terminal or a wireless terminal. A terminal can also be called a system, device, subscriber unit, subscriber station, mobile station, mobile, mobile device, remote station, remote terminal, access terminal, user terminal, terminal, communication device, user agent, user device, or user equipment (UE). A wireless terminal may be a cellular telephone, a satellite phone, a cordless telephone, a Session Initiation Protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA), a handheld device having wireless connection capability, a computing device, or other processing devices connected to a wireless modem. Moreover, various aspects are described herein in connection with a base station. A base station may be utilized for communicating with wireless terminal(s) and may also be referred to as an access point, a Node B, or some other terminology. 
     Moreover, the term “or” is intended to mean an inclusive “or” rather than an exclusive “or.” That is, unless specified otherwise, or clear from the context, the phrase “X employs A or B” is intended to mean any of the natural inclusive permutations. That is, the phrase “X employs A or B” is satisfied by any of the following instances: X employs A; X employs B; or X employs both A and B. In addition, the articles “a” and “an” as used in this application and the appended claims should generally be construed to mean “one or more” unless specified otherwise or clear from the context to be directed to a singular form. 
     The techniques described herein may be used for various wireless communication systems such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA and other systems. The terms “system” and “network” are often used interchangeably. A CDMA system may implement a radio technology such as Universal Terrestrial Radio Access (UTRA), cdma2000, etc. UTRA includes Wideband-CDMA (W-CDMA) and other variants of CDMA. Further, cdma2000 covers IS-2000, IS-95 and IS-856 standards. A TDMA system may implement a radio technology such as Global System for Mobile Communications (GSM). An OFDMA system may implement a radio technology such as Evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM , etc. UTRA and E-UTRA are part of Universal Mobile Telecommunication System (UMTS). 3GPP Long Term Evolution (LTE) is a release of UMTS that uses E-UTRA, which employs OFDMA on the downlink and SC-FDMA on the uplink. UTRA, E-UTRA, UMTS, LTE and GSM are described in documents from an organization named “3rd Generation Partnership Project” (3GPP). Additionally, cdma2000 and UMB are described in documents from an organization named “3rd Generation Partnership Project 2” (3GPP2). Further, such wireless communication systems may additionally include peer-to-peer (e.g., mobile-to-mobile) ad hoc network systems often using unpaired unlicensed spectrums, 802.xx wireless LAN, BLUETOOTH and any other short- or long-range, wireless communication techniques. 
     Various aspects or features will be presented in terms of systems that may include a number of devices, components, modules, and the like. It is to be understood and appreciated that the various systems may include additional devices, components, modules, etc. and/or may not include all of the devices, components, modules etc. discussed in connection with the figures. A combination of these approaches may also be used. 
     The various illustrative logics, logical blocks, modules, and circuits described in connection with the embodiments disclosed herein may be implemented or performed with a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but, in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. Additionally, at least one processor may comprise one or more modules operable to perform one or more of the steps and/or actions described above. 
     Further, the steps and/or actions of a method or algorithm described in connection with the aspects disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium may be coupled to the processor, such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. Further, in some aspects, the processor and the storage medium may reside in an ASIC. Additionally, the ASIC may reside in a user terminal. In the alternative, the processor and the storage medium may reside as discrete components in a user terminal. Additionally, in some aspects, the steps and/or actions of a method or algorithm may reside as one or any combination or set of codes and/or instructions on a machine readable medium and/or computer readable medium, which may be incorporated into a computer program product. 
     In one or more aspects, the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored or transmitted as one or more instructions or code on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A storage medium may be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer. Disk and disc, as used herein, includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and blu-ray disc where disks usually reproduce data magnetically, while discs usually reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media. 
     While the foregoing disclosure discusses illustrative aspects and/or embodiments, it should be noted that various changes and modifications could be made herein without departing from the scope of the described aspects and/or embodiments as defined by the appended claims. Furthermore, although elements of the described aspects and/or embodiments may be described or claimed in the singular, the plural is contemplated unless limitation to the singular is explicitly stated. Additionally, all or a portion of any aspect and/or embodiment may be utilized with all or a portion of any other aspect and/or embodiment, unless stated otherwise.