WO2014152853A2

WO2014152853A2 - Method and apparatus to enable direct link setup in opportunistic multi-rat aggregation systems

Info

Publication number: WO2014152853A2
Application number: PCT/US2014/027983
Authority: WO
Inventors: Amith V. Chincholi; Sanjay Goyal; Tan B. LE; Alpaslan Demir
Original assignee: Interdigital Patent Holdings, Inc.
Priority date: 2013-03-14
Filing date: 2014-03-14
Publication date: 2014-09-25
Also published as: WO2014152853A3; TW201442548A

Abstract

A method performed by a multiple radio-access technology (RAT) capable access point (AP), for communicating the direct link capability and RAT capability between a first station (STA) and a second STA is disclosed. The method may comprise the AP receiving a direct link discovery request message from the first STA using a first common enabled RAT. The AP may select a second common enabled RAT for communication with a second STA. The AP may forward the direct link discovery request message to the second STA using the second common enabled RAT. The first common enabled RAT and the second common enabled RAT may be the same. The AP may receive a direct link setup request message from the first STA using the first common enabled RAT and forward the direct link setup request message to the second STA using the second common enabled RAT.

Description

METHOD AND APPARATUS TO ENABLE DIRECT LINK SETUP IN OPPORTUNISTIC MULTI-RAT AGGREGATION SYSTEMS

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. provisional application

No. 61/783,978, filed on March 14, 2013, the contents of which are hereby incorporated by reference herein.

BACKGROUND

[0002] A multiple radio access technology (multi-RAT) device is a device that is capable of supporting data transmissions over more than one radio access technology (RAT). Multi-RAT devices may be infrastructure devices, for example, an access point (AP), a home node B (HNB), a home evolved Node B (H(e)NB), and the like. Multi-RAT devices may also be client devices, for example, a station (STA) in Wi-Fi, a wireless transmit/receive unit (WTRU) in a cellular system, and the like.

[0003] Opportunistic multi-medium access control (MAC) aggregation

(OMMA) allows multi-RAT devices to aggregate multiple RATs operating over independent spectral bands. Aggregation may be performed above the air interface protocol stacks but below the IP layer. This layer may be referred to as the OMMA layer, which may be common to all RATs. The OMMA layer may also be capable of receiving meta-data and link statistic feedback from each RAT.

[0004] Direct link (DL) communication enables devices to communicate data to one another without the use of an AP. In Institute of Electrical and Electronics Engineers (IEEE) 802.11η, STAs with Quality of Service (QoS) facility may transmit frames directly to another STA by setting up data transfer using direct link setup (DLS). In IEEE 802. llz, DLS is known as tunneled direct-link setup (TDLS). TLDS is characterized by the use of signaling frames that are encapsulated in data frames so that the signaling frames may be transmitted through an access point (AP) transparently. Enabling direct link communication between multi-RAT devices which are capable of aggregating two or more RATs is desired.

SUMMARY

[0005] Methods and apparatus for communicating the direct link capability and radio-access technology (RAT) capability between a first multi- RAT capable station (STA) and a second multi-RAT capable STA are disclosed. The first STA and the second STA may not be aware of each other's RAT capabilities to determine which RATs are common between them. Therefore, RAT capability discovery is desirable in order for two multi-RAT devices to communicate with each other directly, using a direct link. In one example, a multiple RAT capable access point (AP) may receive a direct link discovery request message from the first STA using a first common enabled RAT. The AP may select a second common enabled RAT for communication with the second STA and may forwarding the direct link discovery request message to the second STA using the second common enabled RAT. The second STA may send at least one direct link discovery response message using at least one common enabled RAT associated with the first STA, directly to the first STA.

[0006] Methods and apparatus for setting up a direct link between first multi-RAT capable STA and a second multi-RAT capable STA are disclosed. Methods and apparatus for direct link teardown between a first multi-RAT capable STA and a second multi-RAT capable STA are also disclosed. Methods and apparatus for managing the RAT availability between a first multi-RAT capable STA and a second multi-RAT capable STA are disclosed. Methods and apparatus for dynamically switching RATs and methods and apparatus for transferring an opportunistic multi-medium access control (MAC) aggregation (OMMA) mode of a multi-RAT capable STA are also disclosed. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] A more detailed understanding may be had from the following description, given by way of example in conjunction with the accompanying drawings wherein:

[0008] FIG. 1A is a system diagram of an example communications system in which one or more disclosed embodiments may be implemented;

[0009] FIG. IB is a system diagram of an example wireless transmit/receive unit (WTRU) that may be used within the communications system illustrated in FIG. 1A;

[0010] FIG. 1C is a system diagram of an example radio access network and an example core network that may be used within the communications system illustrated in FIG. 1A;

[0011] FIG. 2 is a diagram illustrating a flow of messages of an example direct link setup (DLS) procedure between two stations (STAs);

[0012] FIG. 3 is a diagram illustrating a flow of messages of an example

TDLS procedure between two stations (STAs);

[0013] FIG. 4 is a diagram of an example multi-RAT device architecture;

[0014] FIG. 5 is a diagram of an example multi-RAT capable wireless system;

[0015] FIG. 6 is a flow call of a basic example DL/RAT capability discovery procedure;

[0016] FIG. 7 is an example format of the address fields in the MAC layer frame of a DL Discovery Request frame sent by a DL initiator STA to an AP;

[0017] FIG. 8 is an example TDLS discovery request frame format sent by a DL initiator STA to an AP.

[0018] FIG. 9 is an example TDLS Link Identifier Element format of the

TDLS discovery request frame; [0019] FIG. 10 is an example format of the address fields in the MAC layer frame of a DL Discovery Request frame sent by an AP to a DL responder STA;

[0020] FIG. 11 is an example TDLS discovery response frame format sent by an AP to a DL responder STA;

[0021] FIG. 12 is a flow call of a basic example DL Setup procedure;

[0022] FIG. 13 is an example format of the address fields in the MAC layer frame of a DL Setup Request frame sent by a DL initiator STA to an AP;

[0023] FIG. 14 is an example TDLS setup request frame format sent by a DL initiator STA to an AP;

[0024] FIG. 15 is an example format of the address fields in the MAC layer frame of a DL Setup Request frame sent by an AP to a DL responder STA;

[0025] FIG. 16 is an example format of the address fields in the MAC layer frame of a DL Setup Response frame sent by a DL responder STA to an AP;

[0026] FIG. 17 is an example TDLS setup response frame format sent by a DL responder STA to an AP;

[0027] FIG. 18 is an example format of the address fields in the MAC layer frame of a DL Setup Response frame sent by an AP to a DL initiator STA;

[0028] FIG. 19 is an example format of the address fields in the MAC layer frame of a DL Setup Confirm frame sent by a DL initiator STA to an AP;

[0029] FIG. 20 is an example TDLS Setup Confirm frame format sent by a DL initiator STA to an AP;

[0030] FIG. 21 is an example format of the address fields in the MAC layer frame of a DL Setup Confirm frame sent by an AP to a DL responder STA;

[0031] FIG. 22 is a call flow of an example teardown procedure over the direct path; [0032] FIG. 23 is a call flow of an example teardown procedure through the AP;

[0033] FIG. 24 is an example format of the address fields in the MAC layer frame of a DL Teardown frame sent by a Teardown Initiator STA to an AP;

[0034] FIG. 25 is an example format of the address fields in the MAC layer frame of a DL Teardown frame sent by an AP to a DL Teardown Responder STA;

[0035] FIG. 26 is an example TDLS Teardown frame format;

[0036] FIG. 27 is an example call flow for RAT availability update management;

[0037] FIG. 28 is an example call flow for dynamic RAT switching; and

[0038] FIG. 29 is a call flow of an example OMMA mode transfer procedure.

DETAILED DESCRIPTION

[0039] FIG. 1A is a diagram of an example communications system 100 in which one or more disclosed embodiments may be implemented. The communications system 100 may be a multiple access system that provides content, such as voice, data, video, messaging, broadcast, etc., to multiple wireless users. The communications system 100 may enable multiple wireless users to access such content through the sharing of system resources, including wireless bandwidth. For example, the communications systems 100 may employ one or more channel access methods, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single-carrier FDMA (SC-FDMA), and the like.

[0040] As shown in FIG. 1A, the communications system 100 may include wireless transmit/receive units (WTRUs) 102a, 102b, 102c, 102d, a radio access network (RAN) 104, a core network 106, a public switched telephone network (PSTN) 108, the Internet 110, and other networks 112, though it will be appreciated that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and/or network elements. Each of the WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and/or communicate in a wireless environment. By way of example, the WTRUs 102a, 102b, 102c, 102d may be configured to transmit and/or receive wireless signals and may include user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a pager, a cellular telephone, a personal digital assistant (PDA), a smartphone, a laptop, a netbook, a personal computer, a wireless sensor, consumer electronics, and the like.

[0041] The communications systems 100 may also include a base station

114a and a base station 114b. Each of the base stations 114a, 114b may be any type of device configured to wirelessly interface with at least one of the WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communication networks, such as the core network 106, the Internet 110, and/or the other networks 112. By way of example, the base stations 114a, 114b may be a base transceiver station (BTS), a Node-B, an eNode B, a Home Node B, a Home eNode B, a site controller, an access point (AP), a wireless router, and the like. While the base stations 114a, 114b are each depicted as a single element, it will be appreciated that the base stations 114a, 114b may include any number of interconnected base stations and/or network elements.

[0042] The base station 114a may be part of the RAN 104, which may also include other base stations and/or network elements (not shown), such as a base station controller (BSC), a radio network controller (RNC), relay nodes, etc. The base station 114a and/or the base station 114b may be configured to transmit and/or receive wireless signals within a particular geographic region, which may be referred to as a cell (not shown). The cell may further be divided into cell sectors. For example, the cell associated with the base station 114a may be divided into three sectors. Thus, in one embodiment, the base station 114a may include three transceivers, i.e., one for each sector of the cell. In another embodiment, the base station 114a may employ multiple -input multiple -output (MIMO) technology and, therefore, may utilize multiple transceivers for each sector of the cell.

[0043] The base stations 114a, 114b may communicate with one or more of the WTRUs 102a, 102b, 102c, 102d over an air interface 116, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, infrared (IR), ultraviolet (UV), visible light, etc.). The air interface 116 may be established using any suitable radio access technology (RAT).

[0044] More specifically, as noted above, the communications system

100 may be a multiple access system and may employ one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and the like. For example, the base station 114a in the RAN 104 and the WTRUs 102a, 102b, 102c may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may establish the air interface 116 using wideband CDMA (WCDMA). WCDMA may include communication protocols such as High-Speed Packet Access (HSPA) and/or Evolved HSPA (HSPA+). HSPA may include High- Speed Downlink Packet Access (HSDPA) and/or High-Speed Uplink Packet Access (HSUPA).

[0045] In another embodiment, the base station 114a and the WTRUs

102a, 102b, 102c may implement a radio technology such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which may establish the air interface 116 using Long Term Evolution (LTE) and/or LTE- Advanced (LTE-A).

[0046] In other embodiments, the base station 114a and the WTRUs

102a, 102b, 102c may implement radio technologies such as IEEE 802.16 (i.e., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 IX, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), GSM EDGE (GERAN), and the like. [0047] The base station 114b in FIG. 1A may be a wireless router, Home

Node B, Home eNode B, or access point, for example, and may utilize any suitable RAT for facilitating wireless connectivity in a localized area, such as a place of business, a home, a vehicle, a campus, and the like. In one embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.11 to establish a wireless local area network (WLAN). In another embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another embodiment, the base station 114b and the WTRUs 102c, 102d may utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, etc.) to establish a picocell or femtocell. As shown in FIG. 1A, the base station 114b may have a direct connection to the Internet 110. Thus, the base station 114b may not be required to access the Internet 110 via the core network 106.

[0048] The RAN 104 may be in communication with the core network

106, which may be any type of network configured to provide voice, data, applications, and/or voice over internet protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. For example, the core network 106 may provide call control, billing services, mobile location-based services, pre-paid calling, Internet connectivity, video distribution, etc., and/or perform high- level security functions, such as user authentication. Although not shown in FIG. 1A, it will be appreciated that the RAN 104 and/or the core network 106 may be in direct or indirect communication with other RANs that employ the same RAT as the RAN 104 or a different RAT. For example, in addition to being connected to the RAN 104, which may be utilizing an E-UTRA radio technology, the core network 106 may also be in communication with another RAN (not shown) employing a GSM radio technology.

[0049] The core network 106 may also serve as a gateway for the

WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the Internet 110, and/or other networks 112. The PSTN 108 may include circuit-switched telephone networks that provide plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices that use common communication protocols, such as the transmission control protocol (TCP), user datagram protocol (UDP) and the internet protocol (IP) in the TCP/IP internet protocol suite. The networks 112 may include wired or wireless communications networks owned and/or operated by other service providers. For example, the networks 112 may include another core network connected to one or more RANs, which may employ the same RAT as the RAN 104 or a different RAT.

[0050] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communications system 100 may include multi-mode capabilities, i.e., the WTRUs 102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks over different wireless links. For example, the WTRU 102c shown in FIG. 1A may be configured to communicate with the base station 114a, which may employ a cellular -based radio technology, and with the base station 114b, which may employ an IEEE 802 radio technology.

[0051] FIG. IB is a system diagram of an example WTRU 102. As shown in FIG. IB, the WTRU 102 may include a processor 118, a transceiver 120, a transmit/receive element 122, a speaker/microphone 124, a keypad 126, a display/touchpad 128, non-removable memory 130, removable memory 132, a power source 134, a global positioning system (GPS) chipset 136, and other peripherals 138. It will be appreciated that the WTRU 102 may include any sub- combination of the foregoing elements while remaining consistent with an embodiment.

[0052] The processor 118 may be a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), a plurality of microprocessors, one or more microprocessors in association with a DSP core, a controller, a microcontroller, Application Specific Integrated Circuits (ASICs), Field Programmable Gate Array (FPGAs) circuits, any other type of integrated circuit (IC), a state machine, and the like. The processor 118 may perform signal coding, data processing, power control, input/output processing, and/or any other functionality that enables the WTRU 102 to operate in a wireless environment. The processor 118 may be coupled to the transceiver 120, which may be coupled to the transmit/receive element 122. While FIG. IB depicts the processor 118 and the transceiver 120 as separate components, it will be appreciated that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip.

[0053] The transmit/receive element 122 may be configured to transmit signals to, or receive signals from, a base station (e.g., the base station 114a) over the air interface 116. For example, in one embodiment, the transmit/receive element 122 may be an antenna configured to transmit and/or receive RF signals. In another embodiment, the transmit/receive element 122 may be an emitter/detector configured to transmit and/or receive IR, UV, or visible light signals, for example. In yet another embodiment, the transmit/receive element 122 may be configured to transmit and receive both RF and light signals. It will be appreciated that the transmit/receive element 122 may be configured to transmit and/or receive any combination of wireless signals.

[0054] In addition, although the transmit/receive element 122 is depicted in FIG. IB as a single element, the WTRU 102 may include any number of transmit/receive elements 122. More specifically, the WTRU 102 may employ MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmit/receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals over the air interface 116.

[0055] The transceiver 120 may be configured to modulate the signals that are to be transmitted by the transmit/receive element 122 and to demodulate the signals that are received by the transmit/receive element 122. As noted above, the WTRU 102 may have multi-mode capabilities. Thus, the transceiver 120 may include multiple transceivers for enabling the WTRU 102 to communicate via multiple RATs, such as UTRA and IEEE 802.11, for example.

[0056] The processor 118 of the WTRU 102 may be coupled to, and may receive user input data from, the speaker/microphone 124, the keypad 126, and/or the display/touchpad 128 (e.g., a liquid crystal display (LCD) display unit or organic light- emitting diode (OLED) display unit). The processor 118 may also output user data to the speaker/microphone 124, the keypad 126, and/or the display/touchpad 128. In addition, the processor 118 may access information from, and store data in, any type of suitable memory, such as the non-removable memory 130 and/or the removable memory 132. The nonremovable memory 130 may include random-access memory (RAM), read-only memory (ROM), a hard disk, or any other type of memory storage device. The removable memory 132 may include a subscriber identity module (SIM) card, a memory stick, a secure digital (SD) memory card, and the like. In other embodiments, the processor 118 may access information from, and store data in, memory that is not physically located on the WTRU 102, such as on a server or a home computer (not shown).

[0057] The processor 118 may receive power from the power source 134, and may be configured to distribute and/or control the power to the other components in the WTRU 102. The power source 134 may be any suitable device for powering the WTRU 102. For example, the power source 134 may include one or more dry cell batteries (e.g., nickel- cadmium (NiCd), nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, and the like.

[0058] The processor 118 may also be coupled to the GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) regarding the current location of the WTRU 102. In addition to, or in lieu of, the information from the GPS chipset 136, the WTRU 102 may receive location information over the air interface 116 from a base station (e.g., base stations 114a, 114b) and/or determine its location based on the timing of the signals being received from two or more nearby base stations. It will be appreciated that the WTRU 102 may acquire location information by way of any suitable location- determination method while remaining consistent with an embodiment.

[0059] The processor 118 may further be coupled to other peripherals

138, which may include one or more software and/or hardware modules that provide additional features, functionality and/or wired or wireless connectivity. For example, the peripherals 138 may include an accelerometer, an e-compass, a satellite transceiver, a digital camera (for photographs or video), a universal serial bus (USB) port, a vibration device, a television transceiver, a hands free headset, a Bluetooth® module, a frequency modulated (FM) radio unit, a digital music player, a media player, a video game player module, an Internet browser, and the like.

[0060] FIG. 1C is a system diagram of the RAN 104 and the core network 106 according to an embodiment. As noted above, the RAN 104 may employ an E-UTRA radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 104 may also be in communication with the core network 106.

[0061] The RAN 104 may include eNode-Bs 140a, 140b, 140c, though it will be appreciated that the RAN 104 may include any number of eNode-Bs while remaining consistent with an embodiment. The eNode-Bs 140a, 140b, 140c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In one embodiment, the eNode-Bs 140a, 140b, 140c may implement MIMO technology. Thus, the eNode-B 140a, for example, may use multiple antennas to transmit wireless signals to, and receive wireless signals from, the WTRU 102a.

[0062] Each of the eNode-Bs 140a, 140b, 140c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the uplink and/or downlink, and the like. As shown in FIG. 1C, the eNode-Bs 140a, 140b, 140c may communicate with one another over an X2 interface.

[0063] The core network 106 shown in FIG. 1C may include a mobility management entity gateway (MME) 142, a serving gateway 144, and a packet data network (PDN) gateway 146. While each of the foregoing elements are depicted as part of the core network 106, it will be appreciated that any one of these elements may be owned and/or operated by an entity other than the core network operator.

[0064] The MME 142 may be connected to each of the eNode-Bs 140a,

140b, 140c in the RAN 104 via an Si interface and may serve as a control node. For example, the MME 142 may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, bearer activation/deactivation, selecting a particular serving gateway during an initial attach of the WTRUs 102a, 102b, 102c, and the like. The MME 142 may also provide a control plane function for switching between the RAN 104 and other RANs (not shown) that employ other radio technologies, such as GSM or WCDMA.

[0065] The serving gateway 144 may be connected to each of the eNode

Bs 140a, 140b, 140c in the RAN 104 via the Si interface. The serving gateway 144 may generally route and forward user data packets to/from the WTRUs 102a, 102b, 102c. The serving gateway 144 may also perform other functions, such as anchoring user planes during inter-eNode B handovers, triggering paging when downlink data is available for the WTRUs 102a, 102b, 102c, managing and storing contexts of the WTRUs 102a, 102b, 102c, and the like.

[0066] The serving gateway 144 may also be connected to the PDN gateway 146, which may provide the WTRUs 102a, 102b, 102c with access to packet- switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices.

[0067] The core network 106 may facilitate communications with other networks. For example, the core network 106 may provide the WTRUs 102a, 102b, 102c with access to circuit- switched networks, such as the PSTN 108, to facilitate communications between the WTRUs 102a, 102b, 102c and traditional land-line communications devices. For example, the core network 106 may include, or may communicate with, an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that serves as an interface between the core network 106 and the PSTN 108. In addition, the core network 106 may provide the WTRUs 102a, 102b, 102c with access to the networks 112, which may include other wired or wireless networks that are owned and/or operated by other service providers.

[0068] Herein, the terminology station (STA) includes, but is not limited to, a wireless transmit/receive unit (WTRU), a user equipment (UE), a mobile station, a fixed or mobile subscriber unit, an AP, a pager, a cellular telephone, a personal digital assistant (PDA), a computer, a mobile Internet device (MID) or any other type of user device capable of operating in a wireless environment. When referred to herein, the terminology access point (AP) includes but is not limited to a base station, a Node-B, a site controller, or any other type of interfacing device capable of operating in a wireless environment.

[0069] Direct link (DL) communication enables devices to communicate data to one another without the use of an AP. In IEEE 802.11η, a station (STA) with quality of service (QoS) facility may enable DL communication, i.e., transmitting frames directly to another STA, by setting up data transfer using direct link setup (DLS). FIG. 2 is a diagram illustrating a flow of messages of an example DLS procedure between two stations (STAs). Referring to FIG. 2, a first STA 202 intending to set up direct link with a second STA 204, transmits a request message 210a for the second STA 204 to an access point (AP) 206. The request message 210a may be a DLS request message. The AP 206 transmits the request message 210b to the second STA 204. The second STA 204 transmits a response message 220a to the AP 206, in response to the received request message 210b. The response message 220a may be a DLS response message. The AP 206 transmits the DLS response message 220b to the first STA 202. In this procedure, both request and response messages pass through the AP non-transparently, i.e., the AP directly participates therein and relays the exchange of the DLS request and response messages between the first STA and the second STA, thereby completing the DLS procedure. After a successful DLS, both STAs may use direct link for data transfers using any of the access mechanisms defined in the IEEE 802.11η standard. In addition, secure communication in DLS may be ensured by performing a PeerKey Handshake procedure.

[0070] A STA-initiated or AP-initiated DLS teardown procedure may be used to teardown a direct link set up between a first STA and a second STA. In a STA-initiated tear down, the first STA may send a DLS teardown frame to the second STA via the AP. The DLS teardown frame passes through the AP non-transparently, i.e., the AP directly participates therein and relays the DLS teardown frame to the second STA. STAs may also maintain an inactivity timer for every negotiated DL. If any STA does not receive a DLS response message to a DLS request message before a timeout event, the STA may initiate the DLS teardown procedure.

[0071] In some instances, a STA may not be able to initiate the DLS teardown procedure, e.g., the AP detects that either end of a DLS link, i.e., one of the peer STAs, has left the basic service set (BSS) without teardown of the DLS link. Thus, the AP may initiate the teardown procedure. In an AP- initiated teardown procedure, the AP may remove one or more STAs from the BSS list and send DLS teardown messages to all the peers of the removed STAs.

[0072] DLS in IEEE 802. llz is known as tunneled direct-link setup

(TDLS). TDLS may be characterized by the use of signaling frames that are encapsulated in data frames so that the signaling frames can be transmitted through an AP transparently, i.e., the AP does not directly participate therein. In TDLS, unlike DLS, the AP does not need to be DL aware, nor does the AP have to support the same set of capabilities that will be used on the DL.

[0073] In TDLS, a discovery procedure is used to discover TDLS capable

STAs in the same BSS. A TDLS initiator STA, that is, the STA initiating the direct link setup procedure, may send a TDLS discovery request frame to a unicast destination address (DA) through the AP. A TDLS capable STA that receives the TDLS discovery request frame may send a TDLS discovery response frame to the requesting STA, via the direct path.

[0074] FIG. 3 is a diagram illustrating a flow of messages of an example

TDLS procedure between two STAs. Referring to FIG. 3, a first STA 302 intending to set up direct link with a second STA 304, transmits a setup request message 310 for requesting DLS to the second STA 304. The setup request message may be a TDLS setup request frame. The message may be transmitted through the AP 306 transparently, i.e., the AP 306 simply relays the request message received from the first STA 302 to the second STA 304. The second STA 304, having received the setup request message 310, transmits a setup response message 320 to the first STA 302 in response to the setup request message 310. The setup response message may be a TDLS setup response frame. Again, the message may be transmitted through the AP 306 transparently, i.e., the AP 306 simply relays the setup response message 320 received from the second STA 304 to the first STA 302. The first STA 302, having received the setup response message 320, may transmit a confirm message 330 to the second STA 304, indicating that the setup response frame is successfully received. The confirm message 330 may be a TDLS setup confirm frame. Note that if a STA has security enabled on the link with an AP, a TDLS peer key (TPK) handshake procedure may be performed during the TDLS setup procedure. After the completion of TDLS, the first STA 302 and the second STA 304, which may also be referred to as peer STAs, may send data frames directly to each other. [0075] In a TDLS teardown procedure, a TDLS peer STA may send a

TDLS teardown frame to the respective TDLS peer STA. In most instances, the TDLS teardown frame may be sent over the direct link. However, when the TDLS peer STA is unreachable via the TDLS direct link, the TDLS teardown frame may be sent through the AP.

[0076] Tunneled DL may operate on a different channel from the AP.

The channel on which the AP is operating may be referred to as the base channel. If the DL is switched to a channel that is not the base channel, then this channel may be referred to as the off-channel. TDLS peer STAs may perform a channel switching procedure to switch from base-channel to off- channel or vice versa.

[0077] TDLS also includes power saving mechanisms, for example peer power save mode (PSM) and peer unscheduled automatic power save delivery (U-ASPD). Peer PSM is based on periodically scheduled service periods and peer-U-APSD is based on unscheduled service periods, which may be used between two STAs that have set up TDLS direct link.

[0078] Methods and apparatus for enabling direct link communication between multi-RAT devices which may aggregate two or more RATs by dynamically scheduling IP traffic across them based on instantaneous link quality feedback from RATs is described. The multi-RAT devices may be infrastructure devices, for example, an access point (AP), a home node B (HNB), a home evolved Node B (H(e)NB), and the like. The multi-RAT devices may also be client devices, for example, a station (STA) in Wi-Fi, a wireless transmit/receive unit (WTRU) in a cellular system, and the like.

[0079] FIG. 4 is a diagram of an example multi-RAT device architecture

400. The example architecture of the multi-RAT device illustrated in FIG. 4 enables multi-RAT aggregation using the opportunistic multi-MAC aggregation (OMMA) layer. Referring to FIG. 4, the example device may contain multiple RAT modules 410a-n. Each RAT module 410a-n may be configured to operate on a specific band. For example, RAT module 410a may be 802.11η PHY/MAC RAT operating over 2.4 GHz ISM band, RAT module 410b may be 802.11af PHY/MAC RAT operating over 512MHz-698MHz TV White Space (TVWS) band, RAT module 410c may be a long term evolution (LTE) RAT operating over a licensed 700 MHz band, and RAT 410d may be Bluetooth RAT operating on 2.4GHz ISM band, etc. The device may contain multiple antenna/radio frequency (RF) front-end pairs 420a-n, corresponding to each RAT module 410a-n. Each antenna/RF front-end pair 420a-n may operate on a specific band, for example, antenna/RF front-end pair 420a may operate on a 2.4GHz ISM band radio, antenna/RF front-end pair 420b may operate on a 512MHz-698MHz TVWS band split as a low band radio and a high band radio, antenna/RF-front end pair 420c may operate on an LTE 700MHz radio, etc. The device may contain an OMMA layer module 430, and an IP layer module 440. The OMMA layer module 430 is a common module between the IP layer module 440 and the multiple RAT modules 410a-n. The OMMA layer module 430 is responsible for allocating IP packets to the individual RATs.

[0080] FIG. 5 is a diagram of an example multi-RAT capable wireless system 500. Referring to FIG. 5, the wireless system may consist of a network terminal (NT), e.g., an AP 505, and a number of user terminals (UTs), e.g., STA 510, 515. Both the NT (i.e., AP 505), and the UTs (i.e., STA 510, 515) have the capability of supporting one or more RATs, e.g., K RATs, where all RATs may operate on different spectral bands. Some pairs of UTs (i.e., STA 510, 515), that can communicate with each other over a direct link may use one or more RATs common to them. Bands may be orthogonal and signals on different bands may not interfere with each other. As shown in FIG. 5, the AP 505 is capable of operating on RAT 1 (506), RAT 2 (507), RAT 3 (508), and RAT 4 (509). STA 510 is also capable of operating on RAT 1 (506) and RAT 2 (507) and thus may communicate with AP 505 over those RATs, as shown. STA 515 is capable of operating on RAT 3 (508) and RAT 4 (509), and thus may communicate with the AP 505 over those RATs, as shown. If STA 510 and STA 515 are capable of setting up a direct link between them, a stream of arriving packets at STA 510 and destined for STA 515 may be sent over one or more common RATs between them. STA 510 and 515 have RATs 5 (511) and RAT 6 (512) common between them, and thus may communicate over these RATS, as shown. However, STA 510 and STA 515 may not be aware of each other's RAT capabilities to determine which RATs are common between them. Therefore, RAT capability discovery is desirable in order for two multi-RAT devices to communicate with each other directly.

[0081] RAT capability discovery may be accomplished in different ways, for example by autonomous discovery, infrastructure-based discovery, or similar methodologies. In autonomous discovery, multi-RAT devices may discover each other autonomously and may share their device capabilities and operating parameters with one another before commencing communication. In infrastructure-based discovery, multi-RAT devices may use an infrastructure device in their vicinity, e.g., an AP, to aid with an initial handshake mechanism between the multi-RAT devices and also to support them with periodic and/or aperiodic updates using management signaling to help maintain the direct link.

[0082] A multi-RAT device may utilize a common multi-medium access control (MAC) address for all RATs. Alternatively, a multi-RAT device may use an individual MAC address for each RAT. In either case, the AP may maintain a database storing the RAT capabilities of all associated STAs with their MAC addresses. TABLE 1 is an example RAT capability database at the AP. Similarly, STAs may store the same information for their associated APs.

TABLE 1: RAT Capability Database at the AP

[0083] In order for a multi-RAT device to discover the DL capability and

RAT capability of a peer multi-RAT device, the multi-RAT device may initiate DL/RAT capability discovery. The basic procedure is illustrated in FIG. 6.

[0084] FIG. 6 is a flow call of an example DL/RAT capability discovery procedure. Referring to FIG. 6, there is shown a DL initiator STA 605, a DL responder STA 610, and an AP 601. The AP 601 is common to both the DL initiator STA 605 and the DL responder STA 610. The DL initiator STA 605, that is, the STA initiating the DLS procedure, wants to send a request message to a peer STA in the same BSS , i.e., DL responder STA 610, to discover that peer STA's DL capability and RAT capability. The request message may be a DL discovery request frame. This request message may be transmitted through the AP 601 using TDLS, i.e. using a TDLS discovery request frame. The DL initiator STA 605 may select a common enabled RAT common to both the DL initiator STA 605 and the AP 601, e.g., RAT 3 (S615). The DL initiator STA 605 may send the request message to the AP using the selected common enabled RAT (S620). If a common MAC address is used for all RATs, all address fields in a MAC layer frame in the request message, i.e., address fields for single-RAT devices, may be mapped to a common MAC address. If individual MAC addresses are used for each RAT, address fields in a MAC layer frame may be formatted as shown in FIG 7.

[0085] FIG. 7 is an example format of the address fields in a MAC layer frame of a DL Discovery Request frame sent by a DL initiator STA to an AP. Referring to FIG. 7, the address fields in the MAC layer frame may be formatted to include address field 705, which may be the AP's MAC Address of the selected common RAT between the AP and the DL initiator STA; address field 710, which may be the DL initiator STA's MAC address of the selected common RAT between the AP and the DL initiator STA; address field 715, which may be the DL responder STA's MAC address to which the DL initiator STA wants to make a request for a specific DL responder, or which may be a broadcast address of a RAT; and address field 720, which may be the DL initiator STA's MAC address for the RAT on which it wants to make the request to the DL responder STA. It should be noted that alternative address fields may be used, and those described are only by way of example.

[0086] FIG. 8 is an example TDLS discovery request frame format 800 sent by a DL initiator STA to an AP. The TDLS discovery request frame format 800 may include various information elements 804, which may be ordered as indicated at 802. The example TDLS discovery request frame format 800 illustrated in FIG. 8 may include the following information element fields: Category, Action, Dialog Token, and Link Identifier. Other information elements may also be used.

[0087] FIG. 9 is an example TDLS Link Identifier Element format 900 of the TDLS discovery request frame. The TDLS Link Identifier Element format 900 may include an Element ID field 902, a Length field 904, a BSSID field 906, DL initiator STA Address field 908, and a DL responder STA Address field 910. Other fields may also be used.

[0088] In the case of multi-RAT STAs, the BSSID field 906 and the DL initiator STA address field 908 may be modified. If a common MAC address is used for all RATs, the BSSID field 906 may be modified to contain a single BSSID of an AP and the DL initiator STA Address field 908 may be modified to contain a single common MAC address for the DL initiator STA. If an individual MAC address is used for each RAT, BSSID field 906 may be modified to include all BSSIDs of all RATs at the AP, and DL initiator STA Address field 908 may be modified to contain all MAC addresses of all RATS at the DL initiator STA. With the above described modification to the TDLS Link Identifier Element format 900, the DL initiator STA may send the information of RATs on which it is able to communicate. The DL initiator STA may send this information, either with the MAC address (i.e., DL initiator STA address field 908 in the Link Identifier element) or by adding a new information element in the DL Discovery Request frame format 800. The DL initiator STA may send this information in the format as shown in Table 2.

Table 2 Example format of the element to send RATs information

[0089] Referring back to FIG. 6, in the case of individual MAC addresses for all RATs, the AP 601 may learn about the DL responder STA 610 by matching the Address field 715 of the MAC layer frame of the DL Discovery Request frame, as shown in FIG. 7, with its database which stores the RAT capability (with MAC address) for all STAs. Note that the AP's database is populated with the MAC addresses for each device connected to it during each device's respective association procedures. After learning about the DL responder STA 610, the AP 601 may select a common enabled RAT with the DL responder STA 610, e.g., RAT 2, to forward the DL Discovery Request frame to the DL responder STA 610 (S625). The AP 601 then forwards the DL Discovery Request frame to the DL responder STA 610 using the selected RAT (S630). Address fields in the MAC layer frame of the DL Discovery Request frame sent from the AP 601 to the DL responder STA 610 may be formatted as shown in FIG. 10.

[0090] FIG. 10 is an example format of the address fields in the MAC layer frame of a DL Discovery Request frame sent by an AP to a DL responder STA. Referring to FIG. 10, the address fields in the MAC layer frame of a DL Discovery Request frame sent from an AP to a DL responder STA may be formatted to include address field 1005, which may be the DL responder STA's MAC Address for the selected common RAT chosen by the AP; address field 1010, which may be the AP's MAC address of the selected common RAT between the AP and the DL responder STA; address field 1015, which may be the DL responder STA's MAC address to which the DL initiator STA wants to make a request for a specific DL responder, or which may be a broadcast address of a RAT; and address field 1020, which may be the DL initiator STA's MAC address for the RAT on which it wants to make the request to the DL responder STA. It should be noted that alternative address fields may be used, and those described are only by way of example.

[0091] A DL capable STA that receives a DL Discovery Request frame with a matching BSSID (at least one matching BSSID in the case of multiple BSSIDs) in the Link Identifier element may send a DL Discovery Response frame directly to the requesting STA. Referring back to FIG. 6, the DL responder STA 610 may learn about the RAT capability of the DL initiator STA 605 through the DL Discovery Request frame. As a result, the DL responder STA 610 may select all common RATs, e.g., RAT 1, RAT 5, RAT 6 (S635) and may send the DL Discovery Response frame on all of the common RATs, e.g., RAT 1, RAT 5, RAT6 (S640a-n) directly to the DL initiator STA 605. The DL Discovery Response messages may be sent using TDLS. Some of the common RATs may not be enabled at that time because of link quality or mobility, etc., so sending on all of the common RATs may avoid the loss of the DL Discovery Response frame. On the other side, the DL initiator STA 605 may consider only the first DL Discovery Response frame and may discard all DL Discovery Response frames (if any) received on other RATs from the DL responder STA 610. The DL responder STA 610 may use the MAC address of the RAT (common MAC address or individual MAC address) on which it sends the frame, used by the DL initiator STA 605 and itself in the MAC addressing of the frame. If there is no RAT common to the DL responder STA 610 and the DL initiator STA 605, then no DL Discovery Response frame may be sent.

[0092] FIG. 11 is an example TDLS Discovery Response frame format

1100. The TDLS Discovery Response frame format 1100 may include various information elements 1104, which may be ordered as indicated at 1102. The example TDLS Discovery Response frame format 1100 may include the following information element fields: Category, Action, Dialog Token, Capability, Supported Rates, Extended Supported Rates, Supported Channels, Robust Security Network Information Element (RSNIE), Extended Capabilities, Fast BSS Transition Information Element (FTIE), Timeout Interval, Supported Regulatory Classes, High Throughput (HT) Capabilities, 20/40 BSS Coexistence, and Link Identifier. Other information elements may also be used.

[0093] In the case of a multi-RAT STA, the following fields may be modified. These fields may be designed for all RATs (i.e., DL responder STA's maximum RAT capability) rather than only for single RAT as in the case of TDLS. Supported rates: In the case of a multi-RAT STA, this element may be modified to indicate the rates which are supported by the STA on each RAT separately.

Extended supported rates: In the case of a multi-RAT STA, this element may be present for a RAT whenever there are more than eight supported rates on that RAT, and it may be optional otherwise.

Supported Channels: In the case of a multi-RAT STA, this element may be modified to contain a list of channel subbands in which the multi- RAT STA is capable of operating for each RAT.

Supported Regulatory Classes: In the case of a multi-RAT STA, this element may be modified to contain the information for each RAT.

Security parameters (i.e., RSNIE, FTIE, Timeout Interval in TDLS case): In the case of a multi-RAT STA, each element related to security parameters (e.g. RSNIE, FTIE, Timeout Interval in IEEE 802.11 case) may be modified to contain a corresponding parameter for each RAT. Capabilities (HT capability, Extended Capability, etc., as in TDLS case): In the case of a multi-RAT STA, each capability element may be modified to contain a corresponding parameter for each RAT.

Link Identifier: In the case of a multi-RAT STA, the following fields of the Link Identifier element may be modified.

o BSSID: This field may be modified to contain either a single BSSID of an AP in the case of a common MAC address or all BSSIDs of all RATs at the AP in the case of an individual MAC address for each RAT.

o DL initiator STA address: This field may be modified to contain either the single common MAC address of the DL initiator in the case of a common MAC address or all MAC addresses of all RATs at the DL responder in the case of an individual MAC address for each RAT. [0094] Table 3, illustrated below, is an exemplary view of the format that the DL initiator STA may use to send all of the above modified elements to the DL responder STA.

Table 3 Format to send information for multi-RAT device

[0095] In Table 3, RAT 1, RAT 2, ... RAT N may be the list of the IDs of all the RATs supported by DL initiator STA. With the above modification, the DL initiator STA may also send the information of the RATs on which it is able to communicate. It may send this information in the same manner as discussed for the DL Discovery Request frame. Thus, after completion of the DL discovery process, the DL initiator STA and DL responder STA may know about each other's RAT capability (with MAC addresses). Each STA that knows about the RAT capability of any other STA may store this information in its RAT capability database in a similar way to that shown in Table 1, as illustrated above.

[0096] A method for establishing a DL between two multi-RAT OMMA devices will now be described. FIG. 12 is a flow call of a basic example DLS procedure. Referring to FIG. 12, there is shown a DL initiator STA 1205, a DL responder STA 1210, and an AP 1201. The AP 1201 is common to both the DL initiator STA 1205 and the DL responder STA 1210. To establish a DL, the initiating multi-RAT device, i.e., the DL initiator STA 1205, may send a setup request message to the intended peer multi-RAT OMMA device, i.e., the DL responder STA 1210. The setup request message may be a DL Setup Request frame. This setup request message may also be transmitted through the AP 1201 using TDLS, i.e., using a TDLS Setup Request frame. If the DL Discovery process has been completed (i.e., the DL initiator STA 1205 has received the DL Discovery Response frame) between the DL initiator STA 1205 and DL responder STA 1210, then the DL initiator STA 1205 may choose one of the common RATs with the DL responder STA 1210 and use the MAC address of that common RAT in the DL Setup Request frame as shown in FIG. 13. If the DL Discovery process has not been performed or completed between the DL initiator STA 1205 and DL responder STA, the DL initiator STA still may send a DL Setup Request to the DL responder STA. The MAC addressing may be done in a similar way as the DL Discovery Request as illustrated in FIG. 7.

[0097] Referring to FIG. 12, the DL initiator STA 1205 may select a common enabled RAT, e.g. RAT 3, with the AP 1201 (S1215). The DL initiator STA 1205 may send a DL Setup Request frame to the AP 1201 on the selected RAT (S1220). The DL initiator STA 1205 and the AP 1201 may update the common enabled RAT between them dynamically. In the case of a common MAC address for all RATs, all address fields in the MAC layer frame of the DL Setup Request frame may be mapped to a common MAC address. In the case of an individual MAC address for each RAT, address fields in the MAC layer frame may be formatted as shown in FIG. 13.

[0098] FIG. 13 is an example format of the address fields in the MAC layer frame of a DL Setup Request frame sent by a DL initiator STA to an AP. Referring to FIG. 13, the address fields in the MAC layer frame may be formatted to include address field 1305, which may be the AP's MAC Address of the selected common RAT, as chosen by the DL initiator STA; address field 1310, which may be the DL initiator STA's MAC address of the selected common RAT between the AP and the DL initiator STA; address field 1315, which may be the DL responder STA's MAC address for the selected common RAT chosen by the DL initiator STA; and address field 1320, which may be the DL initiator STA's MAC address for the selected common RAT with the DL responder STA. It should be noted that alternative address fields may be used, and those described are only by way of example.

[0099] FIG. 14 is an example TDLS setup request frame format 1400 sent by a DL initiator STA to an AP. The TDLS setup request frame format 1400 may include various information elements 1404, which may be ordered as indicated at 1402. The example TDLS setup request frame format 1400 illustrated in FIG. 14 may include the following information element fields: Category, Action, Dialog Token, Capability, Supported Rates, Country, Extended Supported Rates, Supported Channels, RSNIE, Extended Capabilities, Quality of Service (QoS) Capability, FTIE, Timeout Interval, Supported Regulatory Classes, HT Capabilities, 20/40 BSS Coexistence, and Link Identifier. Other information elements may also be used.

[0100] In the case of a multi-RAT STA, the following fields may be modified.

• Supported rates: In the case of a multi-RAT STA, this element may be modified to indicate the rates which are supported by the STA on each RAT separately.

• Extended supported rates: In the case of a multi-RAT STA, this element may be present for a RAT whenever there are more than eight supported rates on that RAT, and it may be optional otherwise.

• Supported Channels: In the case of a multi-RAT STA, this element may be modified to contain a list of channel subbands in which the multi- RAT STA is capable of operating for each RAT.

• QoS Capability: In the case of a multi-RAT STA, QoS capability information should be sent for each RAT.

• Supported Regulatory Classes: In the case of a multi-RAT STA, this element may be modified to contain the information for each RAT.

• Security parameters (i.e., RSNIE, FTIE, Timeout Interval in TDLS case): In the case of a multi-RAT STA, each element related to security parameters (e.g. RSNIE, FTIE, Timeout Interval in IEEE 802.11 case) may be modified to contain a corresponding parameter for each RAT.

• Capabilities (HT capability, Extended Capability, etc., as in TDLS case):

In the case of a multi-RAT STA, each capability element may be modified to contain a corresponding parameter for each RAT.

• Link Identifier: In the case of a multi-RAT STA, the following fields of the Link Identifier element may be modified.

o DL initiator STA address: This field may be modified to contain either the single common MAC address of the DL initiator in the case of a common MAC address or all MAC addresses of all RATs at the DL responder in the case of an individual MAC address for each RAT.

[0101] The DL initiator STA may also send the information for RATs on which it is able to communicate. It may send this information in the same manner as described above for the DL Discovery Request frame.

[0102] Referring back to FIG. 12, in the case of individual MAC addresses for all RATs, the AP 1201 may learn about the DL responder STA 1210 by matching the Address field 1315, as shown in FIG. 13, of the MAC layer frame of the DL Setup Request frame (received from the DL initiator STA 1205) with its database which stores the RAT capability (with MAC address) for all STAs. After learning about the DL responder STA 1210, the AP 1201 may select a common enabled RAT, e.g., RAT 2, with the DL responder STA 1210 (S1225). The AP 1201 may forward the DL Setup Request frame to the DL responder STA 1210 using the common enabled RAT (S1230). The address fields in the MAC layer frame of the DL Setup Request frame (sent from the AP 1201 to the DL responder STA 1210) may be formatted as shown in FIG. 15.

[0103] FIG. 15 is an example format of the address fields in the MAC layer frame of a DL Setup Request frame sent by an AP to a DL responder STA. Referring to FIG. 15, the address fields in the MAC layer frame may be formatted to include address field 1505, which may be the DL responder STA's MAC Address for the selected common RAT, as chosen by the AP; address field 1510, which may be the AP's MAC address of the selected common RAT between the AP and the DL responder STA; address field 1515, which may be the "Address 3" field of the received request from the DL initiator STA; and address field 1520, which may be "Address 4" field of the received request from the DL initiator STA. It should be noted that alternative address fields may be used, and those described are only by way of example.

[0104] Referring back to FIG. 12, in response to the receipt of the DL

Setup Request message by the DL responder STA 1210, a setup response message may be sent from the DL responder STA 1210 to the DL initiator STA 1205. The setup message may be a DL Setup Response frame, which may be transmitted through the AP 1201 using TDLS. The DL responder STA 1210 may select a common enabled RAT, e.g., RAT 2, with the AP 1201 on which to send the DL Setup Response frame (S1235). DL responder STA 1210 may send the DL Setup Response frame to the AP 1201 using the common enabled RAT (S1240). The address fields in the MAC layer frame of the DL Setup Response frame may be formatted as shown in FIG. 16.

[0105] FIG. 16 is an example format of the address fields in the MAC layer frame of a DL Setup Response frame sent by a DL responder STA to an AP. Referring to FIG. 16, the address fields in the MAC layer frame may be formatted to include address field 1605, which may be AP's MAC Address for the selected common RAT chosen by the DL responder STA; address field 1610, which may be the DL responder STA's MAC address for the selected common RAT with the AP ; address field 1615, which may be the "Address 4" field of the DL Setup Request; and address field 1620, which may be the "Address 3" field of the DL Setup Request. As described, in the MAC layer frame, the "Address 3" and "Address 4" fields may be copied from the "Address 4" and "Address 3" fields of the received DL Setup Request, respectively. It should also be noted that alternative address fields may be used, and those described are only by way of example.

[0106] FIG. 17 is an example TDLS Setup Response frame format 1700 sent by a DL responder STA to an AP. The TDLS Setup Response frame format 1700 may include various information elements 1704, which may be ordered as indicated at 1702. The example TDLS setup response frame format 1700 illustrated in FIG. 17 may include the following information element fields: Category, Action, Status Code, Dialog Token, Capability, Supported rates, Country, Extended supported rates, Supported Channels, RSNIE, Extended Capabilities, QoS Capability, FTIE, Timeout Interval IE, Supported Regulatory Classes, HT Capabilities, 20/40 BSS Coexistence, Link Identifier. Other information elements may also be used.

[0107] In the case of a multi-RAT STA, the following fields may be modified.

• Status code: In TDLS, five options are listed for a TDLS responder STA (i.e. status code Ό', '37', etc.) to make its response. In the case of multi- RAT STAs, all those options may remain the same for the DL responder with the following modification in option 2 (section 11.21.4 in IEEE 802.11z).

o The DL responder STA may decline the DL Setup Request frame, in which case, the DL responder STA may respond with a DL Setup Response frame with the status code 37 ("The request has been declined"). A DL setup request may be declined when the any of the BSSIDs in the received Link Identifier element does not match any of the BSSIDs of the DL responder STA of the DL responder STA does not find any common RAT with the DL initiator.

Supported rates: In the case of a multi-RAT STA, this element may be modified to indicate the rates which are supported by the STA on each RAT separately.

QoS Capability: In the case of a multi-RAT STA, QoS capability information should be sent for each RAT.

o BSSID: This field may be modified to contain either a single

BSSID of an AP in the case of a common MAC address or all

BSSIDs of all RATs at the AP in the case of an individual MAC address for each RAT.

[0108] The DL responder STA may also send the information for RATs on which it is able to communicate. It may send this information in the same manner as described above for the DL Discovery Request frame.

[0109] Referring back to FIG. 12, in the case of individual MAC addresses for all RATs, the AP 1201 may learn about the DL initiator STA 1205 by matching the Address field 1615 of the MAC layer frame, as shown in FIG. 16, (received from the DL responder STA 1210) with its database which may store the RAT capability (with MAC address) for all STAs. After learning about the DL initiator STA 1205, the AP 1201 may select a common enabled RAT, e.g., RAT 3, with the DL initiator STA 1205 (S1245). The AP 1201 may forward the DL Setup Response frame to the DL initiator STA 1205 using the common enabled RAT (S1250). Address fields in the MAC layer frame of the DL Setup Response frame (from the AP to the DL initiator) may be formatted as shown in FIG. 18.

[0110] FIG. 18 is an example format of the address fields in the MAC layer frame of a DL Setup Response frame sent by an AP to a DL initiator STA. Referring to FIG. 18, the address fields in the MAC layer frame of a DL Setup Response frame sent by an AP to a DL initiator STA may be formatted to include address field 1805, which may be the DL initiator STA's MAC address for the selected common RAT chosen by the AP; address field 1810, which may be the AP's MAC Address for selected common RAT with the DL initiator STA; address field 1815, which may be the "Address 3" field of the received response from the DL responder STA; and address field 1820, which may be the "Address 4" field of the received response from the DL responder STA. It should also be noted that alternative address fields may be used, and those described are only by way of example. [0111] The DL initiator STA may send a DL Setup Confirm frame to the

DL responder STA if it receives the DL Setup Response with status code zero and before timeout (if defined for DL Setup Response) occurs. This message may be transmitted through the AP. Referring back to FIG. 12, the DL initiator STA 1205 may select a common enabled RAT, e.g. RAT 3, with the AP 1201 (S1255). The DL initiator STA 1205 may send a DL Setup Confirm frame to the AP 1201 using the selected common enabled RAT (S1260). The address fields in the MAC layer frame of the DL Setup Confirm frame may be formatted as shown in FIG. 19.

[0112] FIG. 19 is an example format of the address fields in the MAC layer frame of a DL Setup Confirm frame sent by a DL initiator STA to an AP. Referring to FIG. 19, the address fields in a MAC layer frame of a DL Setup Confirm frame sent by a DL initiator STA to an AP may be formatted to include address field 1905, which may be the AP's MAC Address for the selected common RAT chosen by the DL initiator STA; address field 1910, which may be the DL initiator STA's MAC address for the selected common RAT with the AP; address field 1915, which may be the "Address 4" field of the MAC layer frame of the DL Setup Response frame; and address field 1920, which may be the "Address 3" field of the MAC layer frame of the DL Setup Response. As described, in the MAC layer frame, the "Address 3" and "Address 4" fields may be copied from the "Address 4" and "Address 3" fields of the received DL Setup Response, respectively. It should also be noted that alternative address fields may be used, and those described are only by way of example.

[0113] FIG. 20 is an example TDLS Setup Confirm frame format 2000.

The TDLS Setup Confirm frame format 2000 may include various information elements 2004, which may be ordered as indicated at 2002. The example TDLS Setup Confirm frame format 2000 illustrated in FIG. 20 may include the following information element fields: Category, Action, Status Code, Dialog Token, RSNIE, EDCA Parameter Set, FTIE, Timeout Interval IE, HT Operation, and Link Identifier. Other information elements may also be used.

[0114] For a multi-RAT device, modification in a subset of the information elements may be made, similar to those made for the DL Setup Request. In the case of multi-RAT, security parameters (i.e. RSNIE, FTIE, and Timeout Interval IE), EDCA Parameter Set and HT Operation fields of the DL Setup Confirm frame may contain information for all common RATs between the DL initiator STA and the DL responder STA (after getting a successful DL Setup Response frame from the DL responder STA, the DL initiator STA may know about its common RAT capability with the DL responder STA). In the Link Identifier the following fields may be modified.

• BSSID: This field contains either a single BSSID of an AP in the case of a common MAC address or all BSSIDs of all RATs at the AP in the case of an individual MAC address for each RAT.

• DL initiator STA address: This field contains either a single common MAC address of the DL initiator in the case of a common MAC address or all MAC addresses of the common RATs between the DL initiator and the responder in the case of an individual MAC address for each RAT.

[0115] Referring back to FIG. 12, in the case of individual MAC addresses for all RATs, the AP 1201 may learn about the DL responder STA 1210 by matching the Address field 1915 of the MAC layer frame of the DL Setup Confirm frame, as shown in FIG. 19 (received from the DL initiator STA 1205) with its database which may store the RAT capability (with MAC address) for all STAs. After learning about the DL responder STA 1210, the AP 1201 may select a common enabled RAT, e.g., RAT 2, with the DL responder STA 1210 (S1265). The AP 1201 may forward the DL Setup Confirm frame to the DL responder STA 1210 using the selected common enabled RAT (S1270). Address fields in the MAC layer frame of the DL Setup Confirm frame (from the AP to the DL responder STA) may be formatted as shown in FIG. 21.

[0116] FIG. 21 is an example format of the address fields in the MAC layer frame of a DL Setup Confirm frame sent by an AP to a DL responder STA. Referring to FIG. 21, the address fields in a MAC layer frame of a DL Setup Confirm frame sent by an AP to a DL responder STA may be formatted to include address field 2105, which may be the DL responder STA's MAC address for the selected common RAT chosen by the AP; address field 2110, which may be the AP's MAC Address for selected common RAT with the DL responder STA; address field 2115, which may be the "Address 3" field of the received confirm frame from the DL Initiator; and address field 2120, which may be the "Address 4" field of the received confirm frame from the DL Initiator. It should also be noted that alternative address fields may be used, and those described are only by way of example.

[0117] A method for tearing down a direct link between two multi-RAT

OMMA devices will now be described. A DL peer STA (i.e., either the DL initiator STA or the DL responder STA) may send a DL Teardown frame to the intended DL peer STA to tear down a direct link. The DL Teardown frame may be a TDLS Teardown frame. There may be multiple ways to send this frame, for example, over the direct path or through the AP.

[0118] FIG. 22 is a call flow of an example teardown procedure over the direct path. When an intended DL peer STA is reachable via the DL link, a DL Teardown frame may be sent over the direct path. Referring to FIG. 22, there is shown a teardown initiator STA 2205 and a teardown responder STA 2210. The teardown initiator STA 2205 may select a common RAT, e.g. RAT 4, with the intended DL peer STA, i.e., teardown responder STA 2210 (S2220). The teardown initiator STA 2205 may send a DL Teardown Request frame to the teardown responder STA 2210 on the selected common RAT (S2225). In response to the received DL Teardown Request frame, the teardown responder STA 2210 will send a DL Teardown Response frame to the teardown initiator STA 2205 (S2230).

[0119] FIG. 23 is a call flow of an example teardown procedure through the AP. Referring to FIG. 23, there is shown a teardown initiator STA 2305, a teardown responder STA 2310, and an AP 2301 common to both the teardown initiator STA 2305 and the teardown responder STA 2310. The teardown initiator STA 2305 may select a common RAT, e.g. RAT 4, with the intended DL peer STA, i.e., teardown responder STA 2310 (S2320). The teardown initiator STA 2305 may send a DL Teardown Request frame to the teardown responder STA 2310 on the selected common RAT (S2325). In response to the received DL Teardown Request frame, the teardown responder STA 2310 may send a DL Teardown Response frame to the teardown initiator STA 2305 (S2330). If the DL Teardown Response frame is not received within a timeout period (S2335), then the DL Teardown frame may be sent through the AP 2301. The teardown initiator STA 2305 may select a common RAT, e.g., RAT 1, with the AP (S2340). The teardown initiator STA 2305 may send a DL Teardown Request frame to the AP 2301 using the selected common RAT (S2345). The teardown initiator STA may use the MAC address of that common RAT in the DL Teardown frame as shown in FIG 24, which will be described in more detail below. The AP 2301 may select a common RAT, e.g., RAT 3, with the teardown responder STA 2310 (S2350). The AP 2301 may send the DL Teardown Request frame to the teardown responder STA 2310 using the selected RAT (S2355). In response, the teardown responder STA 2310 may send a DL Teardown Response frame to the AP 2301 using the same common RAT (S2360). The AP 2301 may forward the DL Teardown Response frame to the teardown initiator STA 2305 on the RAT common to them (S2365). In response, the teardown initiator STA 2305 may send a DL Teardown Confirm frame to the AP 2301 using the same common RAT (S2370). The AP 2301 may forward the DL Teardown Confirm frame to the teardown responder STA 2310 using the RAT common to the AP 2301 and the teardown responder STA 2310 (S2375). In the case of a common MAC address for all RATs, all address fields in the MAC layer frame of the message may be mapped to the common MAC address of the devices. In the case of an individual MAC address for each RAT, the address fields in the MAC layer frame may be formatted as shown in FIG. 24.

[0120] FIG. 24 is an example format of the address fields in the MAC layer frame of a DL Teardown frame sent by a Teardown Initiator STA to an AP. Referring to FIG. 24, the address fields in the MAC layer frame may be formatted to include address field 2405, which may be the AP's MAC Address for the selected common RAT chosen by the Teardown Initiator STA; address field 2410, which may be the Teardown Initiator STA's MAC address for the selected common RAT with the AP; address field 2415, which may be the Intended DL peer STA's MAC address for the selected common RAT chosen by the Teardown Initiator STA; and address field 2420, which may be the Teardown Initiator STA's MAC address for the selected common RAT with the Intended DL peer STA. It should also be noted that alternative address fields may be used, and those described are only by way of example.

[0121] In the case of individual MAC addresses for all RATs, the AP may learn about the Intended DL peer STA by matching the Address field 2415 of the MAC layer frame of a DL Teardown frame, as shown in FIG. 24, (received from the Teardown Initiator STA) with its database which may store the RAT capability (with MAC address) for all STAs. After learning about the Intended DL peer STA, it may choose a common enabled RAT with the Intended DL peer STA to forward the DL Teardown frame to the Intended DL peer STA. The address fields in the MAC layer frame (from the AP to the DL responder STA) may be formatted as shown in FIG. 25.

[0122] FIG. 25 is an example format of the address fields in the MAC layer frame of a DL Teardown frame sent by an AP to a DL Teardown Responder STA. Referring to FIG. 25, the address fields in the MAC layer frame may be formatted to include address field 2505, which may be the Intended DL peer STA's MAC address for the selected common RAT chosen by the AP; address field 2510, which may be the AP's MAC Address for the selected common RAT with the Intended DL peer STA; address field 2515, which may be the "Address 3" field of the received confirm frame from the Teardown Initiator STA; and address field 2520, which may be the "Address 4" field of the received confirm frame from the Teardown Initiator STA. It should also be noted that alternative address fields may be used, and those described are only by way of example.

[0123] FIG. 26 is an example TDLS Teardown frame format 2600. The

TDLS Teardown frame format 2600 may include various information elements 2604, which may be ordered as indicated at 2602. The example TDLS Teardown frame format 2600 illustrated in FIG. 26 may include the following information element fields: Category, Action, Reason Code, FTIE, and Link Identifier. Other information elements may also be used.

[0124] For a multi-RAT device, the following modifications in a subset of the above fields may be made:

• Security related parameter (i.e., FTIE in TDLS): Information related to any security parameter may be sent for each RAT.

• Link Identifier: In Link Identifier, the following fields may be modified.

o BSSID: This field may contain either the single BSSID of the AP in the case a of common MAC address or all BSSIDs of all RATs at the AP in the case of an individual MAC address for each RAT. o DL initiator STA address: This field may contain either the single common MAC address of the Teardown initiator in the case of a common MAC address or all MAC addresses of common RATs between the Teardown Initiator and the Intended DL peer STA in the case of an individual MAC address for each RAT.

[0125] A method for RAT availability management will now be described. Each DL STA pair may set up DL by signaling their maximum matched RAT Capability at that time. Thus the DL STA pair may know the common maximum RAT capability between them at the time of the DL setup. But, the RAT availability list for the DL STA pair may change with time depending on several factors (e.g., mobility, link quality fluctuation, etc). Thus, there may be a need for dynamic management of the RAT availability for a DL STA pair in which both of the DL peer STAs learn the RAT availability of each other.

[0126] FIG. 27 is an example call flow for RAT availability update management. Referring to FIG. 27, there is shown a first DL Peer STA 2705 and a second DL Peer STA 2710. In the example provided in FIG. 27, the DL Peer STA 2710 is the DL initiator STA and the DL Peer STA 2705 is the DL responder STA. Each DL Peer STA includes an OMMA Controller (i.e., a RAT Update Management Module), an OMMA Scheduler (i.e., a RAT Update Sender), a STA RAT Capability database, and RATs 1-N. It should be noted that the OMMA Scheduler of DL Peer STA 2710 is not shown in FIG. 27 for the purpose of simplicity of illustration. DL Peer STA 2710 sends a sounding/training signal on all common RATs (i.e., common maximum RAT capability) to DL Peer STA 2705 either periodically or aperidoically (S2720a- n). At the DL Peer STA 2710, each RAT that listens to the sounding/training signal may inform or update the OMMA Controller (i.e., RAT Update Management Module) about the RAT availability (S2725a-n). The update or informing may be accomplished through the signal RAT_Capablities_A3 on the A3 interface. The OMMA Controller of DL Peer STA 2705 updates this information of RAT availability in the STA RAT Capability Database of DL Peer STA 2705 (S2730). The update may be accomplished through a STA_RAT_Capability_Update_Al signal on the Al interface. The OMMA Scheduler of DL Peer STA 2705 (i.e., RAT Update Sender) may query the STA RAT Capability Database of DL Peer STA 2705 for RAT availability list of DL Peer STA 2710 (S2735). This query may be through a STA_RAT_Capability_Query_A4 signal on the A4 interface. The STA RAT Capability Database of DL Peer STA 2405 may send a response to the query, indicating the RAT availability of DL Peer STA 2710 (S2740). The OMMA Scheduler of DL Peer STA 2705 selects a common available RAT, e.g., RAT 2 (S2745). The OMMA Scheduler of DL Peer STA 2705 creates a STA_RAT_A variability message that may include the following parameters:

• Source STA_Addr: Self Address;

• Destination STA_Addr: Address of the DL initiator to which it needs to send this message; and

• RATJds: List of Ids of all RATs which are available [RAT_1, RAT_2 ].

The OMMA Scheduler of DL Peer STA 2705 sends the STA_RAT_Availability message, using the selected common available RAT (S2750), to the DL Peer STA 2710 (S2755). At the DL Peer STA 2710, the STA_RAT_Availability message is received at the selected available RAT. The selected common RAT informs the OMMA Controller of DL Peer STA 2710 of the RAT Capabilities of DL Peer STA 2705 (S2760). This may be accomplished through a RAT_Capablities_A3 signal on the A3 interface. The OMMA Controller of DL Peer STA 2710 may update the RAT Availability information in the STA RAT Capability Database for DL Peer STA 2705 (S2765). This may be accomplished through a STA_RAT_Capability_Update_Al signal on Al interface. In this way, the RAT Availability information of any DL STAs pair may be refreshed. The above procedure may be performed periodically (S2770).

[0127] Sometimes in a multi-RAT device, the packet error rate on some

RATs may become too high due to various reasons. In that case, a receiver that is getting high errored packets on a set of RATs may inform the transmitter not to choose that particular set of RATs to transmit to that receiver. Thus, there is a need for dynamic RAT switching for a DL STA.

[0128] FIG. 28 is an example call flow for dynamic RAT switching. Referring to FIG. 28, there is shown a first DL Peer STA 2805 and a second DL Peer STA 2810. In the example provided in FIG. 28, the DL Peer STA 2805 is the transmitting DL STA and the DL Peer STA 2810 is the receiving DL STA. Each DL Peer STA includes an OMMA Controller (i.e., a RAT Update Management Module), an OMMA Scheduler (i.e., a RAT Update Sender), a STA RAT Capability database, and RATs 1-3. The number of RATs shown in FIG. 28 is for illustrative purposes only, and is not intended to be limiting. A DL Peer STA may include any number of RATs. In addition, the OMMA Scheduler of DL Peer STA 2810 is not shown in FIG. 28 for the purpose of simplicity of illustration. As shown in FIG. 28, DL Peer STA 2810 receives a data communication on RATs 1-3 (S2815a-c). DL Peer STA 2810 continuously receives a high packet error rate on RAT 2 (S2820). It should be noted that DL Peer STA 2810 may continuously receive a high packet error rate on another RAT, or a set of RATs. The OMMA Scheduler of DL Peer STA 2810 queries the STA RAT Availability Database of DL Peer STA 2810 for a RAT Availability list of the DL Peer STA 2805 (transmitter of errored packets) (S2825). This may be accomplished through a STA_RAT_Capability_Query_A4 signal on the A4 interface. The STA RAT Availability Database of DL Peer STA 2810 sends a response to the request, providing the RAT Availability list of the DL Peer STA 2805 (S2830). This may be accomplished through a STA_RAT_Capability_Response_A4 signal on the A4 interface. The DL Peer STA 2810 may remove those RAT(s) on which it is getting a high packet error rate from the list (e.g. a packet error rate above a predetermined value). The OMMA Scheduler of DL Peer STA 2810 selects a common available RAT, e.g., RAT 1 (S2835). The selected common available RAT, e.g., RAT 1, will not be the RAT the DL Peer STA continuously received a high packet error rate. The OMMA Scheduler of DL Peer STA 2810 creates a STA_RAT_Availability message to be sent to DL Peer STA 2805. The STA_RAT_Availability message may include the following parameters:

• Source STA_Addr: Address of the DL peer STA which sends this message;

• Destination STA_Addr: Address of the DL peer STA to which it needs to be sent; • RATJds: List of Ids of all RATs which are available [RAT_1, RAT_2 ] and are not receiving a high packet error rate.

The OMMA Scheduler of DL Peer STA 2810 sends the STA_RAT_Availability message, using the selected common available RAT (S2840), to the DL Peer STA 2805 (S2845). On the DL Peer STA 2805 side, the RAT which receives the STA_RAT_Availability message may inform the OMMA Controller of DL Peer STA 2805 (S2850). This may be accomplished through a RAT_Capablities_A3 signal on the A3 interface. The OMMA Controller of DL Peer STA 2805 may update the RAT Availability information in the STA RAT Capability Database of DL Peer STA 2805 for that STA (S2855). This may be accomplished through a STA_RAT_Capability_Update_Al signal on the Al interface. Thus, DL Peer STA 2805 may not be able to use those high packet errored RATs to transmit to the DL Peer STA 2810 before getting any new update in the STA RAT Capability Database for that DL STA receiver. DL Peer STA 2805 may then send data communications on the available RATs, i.e. RAT 1 and RAT 3 (S2860a-b) to DL Peer STA 2810.

[0129] DL peer STAs may have knowledge of the OMMA mode (e.g., transparent or non-transparent ) of each other, for example, the DL receiver may know about the DL transmitter that is using multiple RATs to send IP flow to it, so that it may aggregate all those packets during reception. Thus, a DL peer STA may transfer its OMMA mode of operation to another DL peer STA if needed. In the case of newly associated DL peer STAs, the DL initiator STA may send its OMMA mode to the DL responder STA during the DL establishment procedure in the DL Setup Confirm frame. Alternatively, the DL initiator STA may send its OMMA mode with a new signal containing the mode. The DL initiator STA may send its OMMA mode before the start of any data communication.

[0130] FIG. 29 is a call flow of an example OMMA mode transfer procedure. Referring to FIG. 29, there is shown a first DL Peer STA 2905 and a second DL Peer STA 2910. In the example provided in FIG. 29, the DL Peer STA 2905 is the DL responder STA and the DL Peer STA 2910 is the DL initiator STA. Each DL Peer STA includes an OMMA Controller, an OMMA Scheduler, a STA RAT Capability database, and RATs 1-N. For purposes of explanation, the DL Responder RAT capability database of STA 2905 STA is not shown. In addition, only a selected RAT is depicted for each DL Peer STA. As indicated above, each DL Peer STA may have one or more RATs available. Referring to FIG. 29, the OMMA Controller of DL initiator STA 2910 selects an OMMA mode in which to operate (S2915). The OMMA Controller of DL initiator STA 2910 communicates its mode decision to the OMMA Scheduler of DL initiator STA 2910 (S2920). This may be accomplished through a OMMA_Mode_Decision_A9 signal on the A9 interface. The OMMA Controller of DL initiator STA 2910 may query the STA RAT Capability Database of DL initiator STA 2910 to obtain the available RATs for the DL responder STA 2905 (S2925). This may be accomplished through a

STA_RAT_Capability_Query_Al signal using the Al interface. The STA RAT Availability Database of DL initiator STA 2910 may send a response to the request, providing the RAT Availability list of the DL responder STA 2905 (S2930). The OMMA Controller of DL initiator STA 2910 may select any one of the available RATs on the RAT Availability list (S2935). The OMMA Controller of DL initiator STA 2910 sends the OMMA mode to the selected RAT (S2940). This may be accomplished through a Mode_to_RAT_A3 signal using the A3 interface. The selected RAT sends a new signal containing the OMMA mode decision to the DL responder STA 2905 (S2945). The new signal that contains the mode may be sent using over-the-air signaling. It may have the following parameters:

• Source STA Address: Address of the DL peer STA that generates the message;

• Destination STA Address: Address of the DL peer STA to which it needs to be sent; and

• Mode: Mode information. At the DL responder STA 2905, the mode information received in the signal containing the mode from the DL initiator STA 2910 may be transferred to the OMMA Controller of the DL responder STA 2905 (S2950). This may be accomplished through a Mode_to_Controller_A3 using the A3 interface. The OMMA Controller of the DL responder STA 2905 may signal to the OMMA Scheduler of the DL responder STA 2605 for this mode of operation (S2955). Further, whenever any Peer STA (either the DL initiator STA or DL responder STA) needs to change the current mode of operation (e.g, from aggregation of multiple RATs to only single RAT communication), it may notify the other Peer STA in the same procedure as discussed above.

[0131] EMBODIMENTS

1. A method for use in a station (STA), the method comprising:

sending a message to an access point (AP), wherein the message includes information for at least one of a plurality of radio access technologies (RATs) available to the STA.

2. The method of embodiment 1, wherein the message is a direct link (DL) discovery request message.

3. The method of embodiment 1, wherein the message is a direct link (DL) setup request message.

4. The method of embodiment 2, further comprising:

receiving, at the STA, a DL discovery response message, wherein the discovery response message includes information for at least one of a plurality of RATs available to the STA.

5. The method of embodiment 3, further comprising:

receiving, at the STA, a DL setup response message, wherein the DL response message includes information for at least one of a plurality of radio access technologies (RATs) available to the STA.

6. The method of embodiment 5, further comprising:

sending a DL setup confirm message. 7. The method of embodiment 1, wherein the message is a direct link (DL) teardown message.

8. The method of embodiment 6, wherein the DL setup confirm message comprises an opportunistic multi-medium access control (MAC) aggregation (OMMA) mode of the STA.

9. A method for use in a station (STA), the method comprising:

sending a direct link (DL) teardown message to an intended DL peer

STA, wherein the message includes information for at least one of a plurality of radio access technologies (RATs) available to the STA.

10. The method as in any one of embodiments 1-9, wherein the information comprises the STA's medium access control (MAC) address for a RAT common to the STA and the AP.

11. The method as in any one of embodiments 1-10, wherein the information further comprises the AP's MAC address for a RAT common to the STA and the AP.

12. The method as in any one of embodiments 1-11, wherein the information further comprises the STA's MAC address for a RAT common to the STA and an intended DL peer STA.

13. The method as in any one of embodiments 1-12, wherein the information further comprises an intended peer STA's MAC address for a RAT common to the STA and the intended DL peer STA.

14. The method as in any one of embodiments 1-13, wherein the information further comprises the AP's MAC address for a RAT common to the AP and an intended peer STA.

15. The method as in any one of embodiments 1-14, wherein the information further comprises an intended peer STA's MAC address for a RAT common to the AP and the intended peer STA.

16. The method as in any one of embodiments 1-15, wherein the information further comprises a list of RATs available to the STA. 17. The method as in any one of embodiments 1-16, further comprising:

maintaining a database of a plurality of RAT capabilities of at least one

AP.

18. A method for use in a station (STA), the method comprising:

sending a sounding signal to an intended peer STA via at least one of a plurality of radio access technologies (RATs) common to the STA and the intended peer STA; and

receiving a RAT availability message via a RAT common to the STA and the intended peer STA, wherein the RAT availability message comprises a list of available RATs.

19. A method for use in a station (STA), the method comprising:

querying a data base for a radio access technology (RAT) availability list on a condition that a packet error rate on at least one of a plurality of RATs used by the STA is above a predetermined value;

receiving the RAT availability list;

removing from the availability list the RATs on which the packet error rate is above the predetermined threshold; and

sending an updated availability list to an intended peer STA via at least one of a plurality of RATs common to the STA and the intended peer STA.

20. A method for use in a station (STA), the method comprising:

querying a data base for a radio access technology (RAT) availability list for an intended peer STA;

selecting an available RAT; and

sending a signal containing an opportunistic multi-medium access control (MAC) aggregation (OMMA) mode of the selected RAT to the intended peer STA.

21. A method for use in an access point (AP), the method comprising: receiving a message from a station (STA), wherein the message includes information for at least one of a plurality of radio access technologies (RATs) available to the STA.

22. The method of embodiment 21, wherein the message is a direct link (DL) discovery request message.

23. The method of embodiment 21, wherein the message is a direct link (DL) setup request message.

24. The method of embodiment 22, further comprising:

sending, to an intended peer STA, the DL discovery response message.

25. The method of embodiment 23, further comprising:

sending, to an intended peer STA, the DL setup request message.

26. The method of embodiment 25 further comprising:

receiving a DL setup confirm message from the STA, and

sending a DL setup confirm message to the intended peer STA.

27. The method of embodiment 21, wherein the message is a direct link (DL) teardown message.

28. The method of embodiment 26, wherein the received DL setup confirm message comprises an opportunistic multi-medium access control (MAC) aggregation (OMMA) mode of the STA.

29. The method as in any one of embodiments 21-28, wherein the information comprises the STA's medium access control (MAC) address for a RAT common to the STA and the AP.

30. The method as in any one of embodiments 21-29, wherein the information further comprises the AP's MAC address for a RAT common to the STA and the AP.

31. The method as in any one of embodiments 22-30, wherein the information further comprises the STA's MAC address for a RAT common to the STA and an intended DL peer STA. 32. The method as in any one of embodiments 21-31, wherein the information further comprises an intended peer STA's MAC address for a RAT common to the STA and the intended DL peer STA.

33. The method as in any one of embodiments 21-32 wherein the information further comprises the AP's MAC address for a RAT common to the AP and an intended peer STA.

34. The method as in any one of embodiments 21-33 wherein the information further comprises an intended peer STA's MAC address for a RAT common to the AP and the intended peer STA.

35. The method as in any one of embodiments 21-34 wherein the information further comprises a list of RATs available to the STA.

36. The method as in any one of embodiments 21-35, the method further comprising maintaining a database of a plurality of RAT capabilities of at least one STA.

37. A station (STA) configured to perform at least part of the method as in any one of embodiments 1-20.

38. An access point (AP) configured to perform at least part of the method as in any one of embodiments 21-36.

39. A wireless communication system configured to perform at least part of the method as in any one of embodiments 1-36.

[0132] Although features and elements are described above in particular combinations, one of ordinary skill in the art will appreciate that each feature or element can be used alone or in any combination with the other features and elements. In addition, the methods described herein may be implemented in a computer program, software, or firmware incorporated in a computer- readable medium for execution by a computer or processor. Examples of computer-readable media include electronic signals (transmitted over wired or wireless connections) and computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, a read only memory (ROM), a random access memory (RAM), a register, cache memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magneto -optical media, and optical media such as CD- ROM disks, and digital versatile disks (DVDs). A processor in association with software may be used to implement a radio frequency transceiver for use in a WTRU, UE, terminal, base station, RNC, or any host computer.

Claims

CLAIMS What is claimed is:

1. A method performed by a multiple radio-access technology (RAT) capable access point (AP), for communicating the direct link capability and RAT capability between a first station (STA) and a second STA, the method comprising:

receiving a direct link discovery request message from the first STA using a first common enabled RAT;

selecting a second common enabled RAT for communication with a second STA; and

forwarding the direct link discovery request message to the second STA using the second common enabled RAT.

2. The method of claim 1, wherein the first common enabled RAT and the second common enabled RAT are the same.

3. The method of claim 1, further comprising:

determining the RAT capability of the second STA.

4. The method of claim 3, wherein the determining the RAT capability of the second STA includes comparing the MAC address associated with the second STA with a database, wherein the database includes the RAT capability for all associated STAs.

5. The method of claim 1, wherein the first STA and the second STA are in the same basic service set (BSS).

6. The method of claim 1, wherein the received direct link discovery request message includes a media access control (MAC) address of the common enabled RAT associated with the AP, a MAC address of the common enabled RAT associated with the first STA, a MAC address associated with the second STA.

7. The method of claim 6, wherein the received direct link discovery request message further includes a MAC address of the RAT the first STA desires to use to make the request to the second STA.

8. The method of claim 7, wherein the received direct link discovery request message further includes BSS identities of all RATs associated with the AP and MAC addresses of all RATs associated with the first STA.

9. The method of claim 1, further comprising:

receiving a direct link setup request message from the first STA using the first common enabled RAT ;

forwarding the direct link setup request message to the second STA using the second common enabled RAT;

receiving a direct link setup response message from the second STA using the first common enabled RAT; and

forwarding the direct link setup response message to the first STA using the second common enabled RAT.

10. The method of claim 9, further comprising:

receiving a direct link setup confirm message from the first STA using the first common enabled RAT; and

forwarding the direct link setup confirm message to the second STA using the second common enabled RAT.

11. The method of claim 1, further comprising:

dynamically updating the first common enabled RAT; and dynamically updating the second common enabled RAT.

12. A multiple radio-access technology (RAT) capable access point (AP), for communicating the direct link capability and RAT capability between a first station (STA) and a second STA, the multiple RAT capable AP comprising:

a receiver configured to receive a direct link discovery request message from the first STA using a first common enabled RAT;

a processor configured to select a second common enabled RAT for communication with a second STA; and

transmitter configured to forward the direct link discovery request message to the second STA using the second common enabled RAT.

13. The multiple RAT capable AP of claim 12, wherein the first common enabled RAT and the second common enabled RAT are the same.

14. The multiple RAT capable AP of claim 12, wherein the processor is further configured to determine the RAT capability of the second STA.

15. The multiple RAT capable AP of claim 14, wherein the

determining the RAT capability of the second STA includes comparing the MAC address associated with the second STA with a database, wherein the database includes the RAT capability for all associated STAs.

16. The multiple RAT capable AP of claim 12, wherein the first STA and the second STA are in the same basic service set (BSS).

17. The multiple RAT capable AP of claim 12, wherein the received direct link discovery request message includes a media access control (MAC) address of the common enabled RAT associated with the AP, a MAC address of the common enabled RAT associated with the first STA, a MAC address associated with the second STA.

18. The multiple RAT capable AP of claim 17, wherein the received direct link discovery request message further includes a MAC address of the RAT the first STA desires to use to make the request to the second STA.

19. The multiple RAT capable AP of claim 12, wherein the received direct link discovery request message further includes BSS identities of all RATs associated with the AP, and MAC addresses of all RATs associated with the first STA.

20. The multiple RAT capable AP of claim 12, wherein:

the receiver is further configured to:

receive a direct link setup request message from the first STA using the first common enabled RAT; and

receive a direct link setup response message from the second STA using the second common enabled RAT; and

the transmitter further configured to:

forward the direct link setup request message to the second STA using the second common enabled RAT; and

forward the direct link setup response message to the first STA using the first common enabled RAT.

21. The multiple RAT capable AP of claim 20, wherein:

the receiver is further configured to receive a direct link setup confirm message from the first STA using the first common enabled RAT; and

the transmitter is further configured to forward the direct link setup confirm message to the second STA using the second common enabled RAT.

22. The multiple RAT capable AP of claim 12, wherein: the processor is further configured to:

dynamically update the first common enabled RAT; and

dynamically update the second common enabled RAT.

23. A method performed by a multiple radio-access technology (RAT) capable station (STA), for determining the direct link capability and RAT capability of a second STA, the method comprising:

selecting a first common enabled RAT associated with a multiple RAT capable access point (AP);

sending a direct link discover request message to the AP intended for a second STA using the first common enabled RAT associated with the multiple RAT capable AP;

receiving at least one direct link discovery response message from the second STA using at least one common enabled RAT associated with the second STA.

24. The method of claim 23, wherein the multiple RAT capable AP is common to the first STA and the second STA.

25. The method of claims 23, wherein the first STA and the second STA are in the same basic service set (BSS).

26. The method of claim 23, wherein the direct link discovery request message includes a media access control (MAC) address of the common enabled RAT associated with the AP, a MAC address of the common enabled RAT associated with the first STA, a MAC address associated with the second STA.

27. The method of claim 26, wherein the direct link discovery request message further includes a MAC address of the RAT the first STA desires to use to make the request to the second STA.

28. The method of claim 27, wherein the direct link discovery request message further includes MAC addresses of all RATs associated with the first STA.

29. The method of claim 23, further comprising:

storing RAT capability information of the second STA in a database.

30. The method of claim 23, further comprising:

sending a direct link setup request message to the multiple RAT capable AP using the first common enabled RAT associated with the multiple RAT capable AP;

receiving a direct link setup response message from the multi RAT capable AP using the first common enabled RAT associated with the multiple RAT capable AP; and

sending a direct link setup confirm to the multiple RAT capable AP using the first common enabled RAT associated with the multiple RAT capable AP.