Patent Publication Number: US-10321347-B2

Title: Method and apparatus for integrating different radio access technologies using carrier aggregation

Description:
This application is a continuation of U.S. patent application Ser. No. 15/076,101 filed Mar. 21, 2016, which is a continuation of U.S. patent application Ser. No. 13/646,160 filed Oct. 5, 2012, which issued as U.S. Pat. No. 9,294,926 on Mar. 22, 2016, which claims the benefit of U.S. Provisional Application No. 61/544,853, filed Oct. 7, 2011, and U.S. Provisional Application No. 61/653,753, filed May 31, 2012, the contents of which are hereby incorporated by reference herein. 
    
    
     FIELD OF THE INVENTION 
     This application is related to wireless communications. 
     BACKGROUND 
     Recent growth in data traffic driven by mobile applications on smart phone devices, tablets, and the like has continued to strain the capacity of today&#39;s networks. Therefore, network operators are increasingly utilizing un-licensed WiFi spectrum to cope with such network congestion, and this trend is expected to accelerate further as traffic demand continues to grow. 
     The use of unlicensed spectrum is a cost-effective means to add the needed capacity, given the limited availability and high cost of licensed spectrum. Currently, a wireless local area network (WLAN) may be integrated as a separate access network to the third generation partnership project (3GPP) evolved packet core (EPC). This may result in extra costs for deploying the complete WLAN access network, and impact the 3GPP core network entities. Existing WiFi offload solutions may be based on this deployment model of distinct 3GPP and WLAN access networks using a common core with selective switching of flows based on operator/user policies. 
     Other solutions are possible that result in a tighter integration and aggregation of 3GPP access network components with WLAN access networks without any impact to and reusing the same 3GPP core network elements. These solutions may enhance the overall user experience without degrading quality of service (QoS), mobility, security and power management when capacity is expanded to unlicensed spectrum. 
     It would be desirable to achieve such optimized capacity extension without duplicating any functionality already provided by 3GPP core network elements, (e.g., through use of opportunistic carrier aggregation at the edge of radio network, i.e., in the evolved Node-B (eNB)), while minimizing any changes to the WLAN access network/air-interface. 
     SUMMARY 
     Methods and apparatuses are described. A method of configuring a Radio Resource Control (RRC)_Connected wireless transmit/receive unit (WTRU) for wireless local area network (WLAN) cell measurement includes receiving, by the WTRU, an RRCConnectionReconfiguration message. The RRCConnectionReconfiguration message includes a measurement configuration that includes at least one wireless local area network (WLAN) measurement object on which the WTRU is to perform measurement and at least one measurement reporting configuration including at least an indication that measurement reporting is to be at least one of periodic and event-triggered. At least one measurement is performed on the at least on WLAN measurement object. A measurement report is provided based on the at least one measurement reporting configuration. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more detailed understanding may be had from the following description, given by way of example in conjunction with the accompanying drawings wherein: 
         FIG. 1A  shows an example communications system in which one or more described embodiments may be implemented; 
         FIG. 1B  shows an example wireless transmit/receive unit (WTRU) that may be used within the communications system shown in  FIG. 1A ; 
         FIG. 1C  shows an example radio access network and an example core network (CN) that may be used within the communications system shown in  FIG. 1A ; 
         FIG. 2  shows an example evolved Node-B (eNB) with multiple millimeter-wave (mmW) base stations (mBs), highlighting the mmW layer; 
         FIG. 3  shows an example overall Evolved Universal Terrestrial Radio Access Network (E-UTRAN) architecture with access point (AP); 
         FIG. 4  shows an example overall E-UTRAN architecture with AP, non co-located deployment; 
         FIG. 5  shows an example overall E-UTRAN architecture with AP, non co-located deployment; 
         FIG. 6  shows an example overall E-UTRAN architecture with AP, co-located deployment with AP gateway (GW) node; 
         FIG. 7  shows an example overall E-UTRAN architecture with AP, non co-located deployment with AP GW; 
         FIG. 8  shows an example collection of basis service set (BSSs) forming an extended service set (ESS); 
         FIG. 9  shows an example user-plane protocol stack view; 
         FIG. 10  shows an example medium access control (MAC) layer aggregation across long term evolution (LTE) and Institute of Electrical and Electronics Engineers (IEEE) 802.11 radio access technologies (RATs); 
         FIG. 11  shows an example uplink (UL) transport channels for an LTE and IEEE 802.11 RAT aggregated system; 
         FIG. 12  shows an example downlink (DL) transport channels for an LTE and IEEE 802.11 RAT aggregated system; 
         FIG. 13  shows an example architecture for below the MAC aggregation across LTE and IEEE 802.11 RATs; 
         FIG. 14  shows an example DL protocol stack view for below the MAC aggregation across LTE and IEEE 802.11 RATs; 
         FIG. 15  shows an example UL protocol stack view for below the MAC aggregation across LTE and IEEE 802.11 RATs; 
         FIG. 16  shows an example wireless local area network (WLAN) Abstraction Layer relation to other wireless transmit/receive unit (WTRU) protocol layers; 
         FIG. 17  shows an example LTE access stratum-service management entity (AS-SME); 
         FIG. 18  shows an example Measurement Report Field format for Beacon Report; 
         FIGS. 19A and 19B  show an example message sequence flow and procedure for measurement configuration and execution; 
         FIG. 20  shows an example procedure of the LTE AS-SME measurement processing; 
         FIGS. 21A and 21B  show an example cellular integration with 802.11 initial mobility domain association; 
         FIG. 22  shows an example cellular-assisted initial mobility domain association; 
         FIG. 23  shows an example cellular-assisted initial mobility domain association without WLAN authentication; 
         FIG. 24  shows an example of implicit transitioning between short service interval (SI) and long SI, and their alignment with LTE short discontinuous reception (DRX) and long DRX; 
         FIG. 25  shows an example message sequence flow and procedure for cellular-assisted 802.11 RAT addition and inter AP transfer for uplink; 
         FIGS. 26A and 26B  show an example of fast inter AP transition, no cellular layer assistance; 
         FIGS. 27A and 27B  show an example of cellular assisted AP to AP transfer; 
         FIGS. 28A and 28B  show an example of cellular assisted AP to AP transfer with optimized security procedures; 
         FIG. 29  shows an example of cellular-assisted fast BSS transition without WLAN authentication; and 
         FIG. 30  shows an example timeline for a combined logical channel prioritization (LCP) execution and IEEE 802.11 transmissions. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1A  shows an example communications system  100  in which one or more described embodiments may be implemented. The communications system  100  may be a multiple access system that provides content, such as voice, data, video, messaging, broadcast, and the like, 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. 
     As shown in  FIG. 1A , the communications system  100  may include WTRUs  102   a,    102   b,    102   c,    102   d,  a radio access network (RAN)  104 , a core network (CN)  106 , a public switched telephone network (PSTN)  108 , the Internet  110 , and other networks  112 , though it will be appreciated that the described embodiments contemplate any number of WTRUs, base stations, networks, and/or network elements. Each of the WTRUs  102   a,    102   b,    102   c,    102   d  may be any type of device configured to operate and/or communicate in a wireless environment. By way of example, the WTRUs  102   a,    102   b,    102   c,    102   d  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 notebook, a personal computer, a wireless sensor, consumer electronics, and the like. 
     The communications systems  100  may also include a base station  114   a  and a base station  114   b.  Each of the base stations  114   a,    114   b  may be any type of device configured to wirelessly interface with at least one of the WTRUs  102   a,    102   b,    102   c,    102   d  to facilitate access to one or more communication networks, such as the CN  106 , the Internet  110 , and/or the other networks  112 . By way of example, the base stations  114   a,    114   b  may be a base transceiver station (BTS), a Node-B, an evolved Node-B (eNB), a Home Node-B (HNB), a Home eNB (HeNB), a site controller, an access point (AP), a wireless router, and the like. While the base stations  114   a,    114   b  are each depicted as a single element, it will be appreciated that the base stations  114   a,    114   b  may include any number of interconnected base stations and/or network elements. 
     The base station  114   a  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, and the like. The base station  114   a  and/or the base station  114   b  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  114   a  may be divided into three sectors. Thus, in one embodiment, the base station  114   a  may include three transceivers, i.e., one for each sector of the cell. In another embodiment, the base station  114   a  may employ multiple-input multiple-output (MIMO) technology and, therefore, may utilize multiple transceivers for each sector of the cell. 
     The base stations  114   a,    114   b  may communicate with one or more of the WTRUs  102   a,    102   b,    102   c,    102   d  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, and the like). The air interface  116  may be established using any suitable radio access technology (RAT). 
     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  114   a  in the RAN  104  and the WTRUs  102   a,    102   b,    102   c  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 (DL) packet access (HSDPA) and/or high-speed uplink (UL) packet access (HSUPA). 
     In another embodiment, the base station  114   a  and the WTRUs  102   a,    102   b,    102   c  may implement a radio technology such as evolved UTRA (E-UTRA), which may establish the air interface  116  using long term evolution (LTE) and/or LTE-Advanced (LTE-A). 
     In other embodiments, the base station  114   a  and the WTRUs  102   a,    102   b,    102   c  may implement radio technologies such as IEEE 802.16 (i.e., worldwide interoperability for microwave access (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000 evolution-data optimized (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 RAN (GERAN), and the like. 
     The base station  114   b  in  FIG. 1A  may be a wireless router, HNB, HeNB, or AP, 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  114   b  and the WTRUs  102   c,    102   d  may implement a radio technology such as IEEE 802.11 to establish a wireless local area network (WLAN). In another embodiment, the base station  114   b  and the WTRUs  102   c,    102   d  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  114   b  and the WTRUs  102   c,    102   d  may utilize a cellular-based RAT, (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, and the like), to establish a picocell or femtocell. As shown in  FIG. 1A , the base station  114   b  may have a direct connection to the Internet  110 . Thus, the base station  114   b  may not be required to access the Internet  110  via the CN  106 . 
     The RAN  104  may be in communication with the CN  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  102   a,    102   b,    102   c,    102   d.  For example, the CN  106  may provide call control, billing services, mobile location-based services, pre-paid calling, Internet connectivity, video distribution, and the like, 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 CN  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 CN  106  may also be in communication with another RAN (not shown) employing a GSM radio technology. 
     The CN  106  may also serve as a gateway for the WTRUs  102   a,    102   b,    102   c,    102   d  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 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 CN connected to one or more RANs, which may employ the same RAT as the RAN  104  or a different RAT. 
     Some or all of the WTRUs  102   a,    102   b,    102   c,    102   d  in the communications system  100  may include multi-mode capabilities, i.e., the WTRUs  102   a,    102   b,    102   c,    102   d  may include multiple transceivers for communicating with different wireless networks over different wireless links. For example, the WTRU  102   c  shown in  FIG. 1A  may be configured to communicate with the base station  114   a,  which may employ a cellular-based radio technology, and with the base station  114   b,  which may employ an IEEE 802 radio technology. 
       FIG. 1B  shows an example WTRU  102  that may be used within the communications system  100  shown in  FIG. 1A . As shown in  FIG. 1B , the WTRU  102  may include a processor  118 , a transceiver  120 , a transmit/receive element, (e.g., an antenna),  122 , a speaker/microphone  124 , a keypad  126 , a display/touchpad  128 , a non-removable memory  130 , a removable memory  132 , a power source  134 , a global positioning system (GPS) chipset  136 , and 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. 
     The processor  118  may be a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), a microprocessor, one or more microprocessors in association with a DSP core, a controller, a microcontroller, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) circuit, an 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. 1B  depicts the processor  118  and the transceiver  120  as separate components, the processor  118  and the transceiver  120  may be integrated together in an electronic package or chip. 
     The transmit/receive element  122  may be configured to transmit signals to, or receive signals from, a base station (e.g., the base station  114   a ) 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. The transmit/receive element  122  may be configured to transmit and/or receive any combination of wireless signals. 
     In addition, although the transmit/receive element  122  is depicted in  FIG. 1B  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 . 
     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. 
     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 non-removable 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). 
     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), and the like), solar cells, fuel cells, and the like. 
     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  114   a,    114   b ), and/or determine its location based on the timing of the signals being received from two or more nearby base stations. The WTRU  102  may acquire location information by way of any suitable location-determination method while remaining consistent with an embodiment. 
     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. 
       FIG. 1C  shows an example RAN  104  and an example CN  106  that may be used within the communications system  100  shown in  FIG. 1A . As noted above, the RAN  104  may employ an E-UTRA radio technology to communicate with the WTRUs  102   a,    102   b,    102   c  over the air interface  116 . The RAN  104  may also be in communication with the CN  106 . 
     The RAN  104  may include eNBs  140   a,    140   b,    140   c,  though it will be appreciated that the RAN  104  may include any number of eNBs while remaining consistent with an embodiment. The eNBs  140   a,    140   b,    140   c  may each include one or more transceivers for communicating with the WTRUs  102   a,    102   b,    102   c  over the air interface  116 . In one embodiment, the eNBs  140   a,    140   b,    140   c  may implement MIMO technology. Thus, the eNB  140   a,  for example, may use multiple antennas to transmit wireless signals to, and receive wireless signals from, the WTRU  102   a.    
     Each of the eNBs  140   a,    140   b,    140   c  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 UL and/or DL, and the like. As shown in  FIG. 1C , the eNBs  140   a,    140   b,    140   c  may communicate with one another over an X2 interface. 
     The CN  106  shown in  FIG. 1C  may include a mobility management entity (MME)  142 , a serving gateway  144 , and a packet data network (PDN) gateway (GW)  146 . While each of the foregoing elements is depicted as part of the CN  106 , it will be appreciated that any one of these elements may be owned and/or operated by an entity other than the CN operator. 
     The MME  142  may be connected to each of the eNBs  140   a,    140   b,    140   c  in the RAN  104  via an S1 interface and may serve as a control node. For example, the MME  142  may be responsible for authenticating users of the WTRUs  102   a,    102   b,    102   c,  bearer activation/deactivation, selecting a particular serving gateway during an initial attach of the WTRUs  102   a,    102   b,    102   c,  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. 
     The serving gateway  144  may be connected to each of the eNBs  140   a,    140   b,    140   c  in the RAN  104  via the S1 interface. The serving gateway  144  may generally route and forward user data packets to/from the WTRUs  102   a,    102   b,    102   c.  The serving gateway  144  may also perform other functions, such as anchoring user planes during inter-eNB handovers, triggering paging when DL data is available for the WTRUs  102   a,    102   b,    102   c,  managing and storing contexts of the WTRUs  102   a,    102   b,    102   c,  and the like. 
     The serving gateway  144  may also be connected to the PDN gateway  146 , which may provide the WTRUs  102   a,    102   b,    102   c  with access to packet-switched networks, such as the Internet  110 , to facilitate communications between the WTRUs  102   a,    102   b,    102   c  and IP-enabled devices. 
     The CN  106  may facilitate communications with other networks. For example, the CN  106  may provide the WTRUs  102   a,    102   b,    102   c  with access to circuit-switched networks, such as the PSTN  108 , to facilitate communications between the WTRUs  102   a,    102   b,    102   c  and traditional land-line communications devices. For example, the CN  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 CN  106  and the PSTN  108 . In addition, the CN  106  may provide the WTRUs  102   a,    102   b,    102   c  with access to other networks  112 , which may include other wired or wireless networks that are owned and/or operated by other service providers. 
     Even in un-licensed spectrum, higher frequencies enable use of large bandwidth to achieve very high data rates. While making use of larger bandwidth has always been a part of meeting predictions based on Cooper&#39;s Law, additional spectrum has always been added at the “lower” frequencies (i.e., below 3 GHz). This has had an approximately linear impact on total capacity. However, there is a synergetic effect to be exploited at higher frequencies, namely spatial reuse. In order to close the link budget for a millimeter wave (mmW) band, highly directional antennas may be required. For example, in IEEE 802.11 such a system using 60 GHz may be introduced in IEEE 802.11ad.  FIG. 2  shows an evolved Node-B (eNB)  200  with access points (AP)  205  with, for example, multiple mmW layers  210  or any 802.11 RAT or spectrum, to multiple WTRUs  215 . 
     The millimeter wave (mmW) hotspot concept (mmW hotspot) project envisions that the mmW layer may be tightly coupled with an LTE system, using a carrier aggregation approach. For such an mmW plus an advanced LTE (LTE-A) hybrid system, mmW carriers may be seen as secondary carriers. Services to a mmW hotspot capable wireless transmit/receive unit (WTRU) may be provided over mmW and LTE bands simultaneously. Overlapping coverage from multiple mmW base stations (mBs)/access points (APs) may be deemed possible. Data is routed by the network to the mB(s) with better reach based on feedback. Thus, mmW feedback may be carried by LTE-A. 
     In such a system, all control signaling such as system information, paging, random access channel (RACH) access, radio resource control (RRC) and non-access stratum (NAS) signaling, (signaling radio bearers), and multicast traffic may be provided via LTE-A. In one embodiment, low throughput and delay sensitive traffic may also be provided via LTE-A, and high throughput traffic may be routed via an mmW system, such as IEEE 802.11ad or its successors. Optimal scheduling of data may be based on traffic class, link availability, user-class, and load balancing. This may be enabled by dynamic scheduling (at or near transmission timing interval (TTI) level) between LTE-A and mmW bands. 
     Although the descriptions provided below use LTE as an example 3GPP air-interface to aid understanding, a similar mechanism may be applied to high speed packet access (HSPA) or other air-interfaces to achieve tighter integration with IEEE 802.11 The alternatives and modifications required for the logical channel prioritization (LCP) algorithm may be handled separately from the architecture alternatives. It is presumed that the each architectural alternative may use any of the LCP modification alternatives. 
     Described herein are example network architectures for enabling tight integration of a 3GPP radio access network (RAN) and an Institute of Electrical and Electronics Engineers (IEEE) 802.11 system. In the below descriptions, the AP may refer to an 802.11 device (e.g. 802.11ad) and the eNB may refer to the cellular node. These defined logical interfaces may operate over any physical interfacing options, and may be configured to operate over existing or new Layer  2  or Layer  3  messaging, (e.g. Internet Protocol (IP) or General packet radio service (GPRS) Tunneling Protocol (GTP)). Each AP node may be optionally managed by an AP Management System (AP-MS), which provides an operations, administration and maintenance (OAM) interface to support startup, initial configuration and management of AP nodes. It is assumed that the eNB-AP link is secure. 
     As stated above,  FIG. 2  shows an example architecture  200  that includes an evolved Node-B (eNB)  202  with APs  205 . The APs  205  may communicate with WTRUs  215  over, for example, multiple mmW layers  210  or any 802.11 RAT or spectrum. 
       FIG. 3  shows an example overall Evolved Universal Terrestrial Radio Access Network (E-UTRAN) architecture  300  with AP. In a co-located deployment, an AP  305  and eNB  310  are assumed to be physically located in the same box, such that there is no physical link required to communicate between the two entities. The two entities may be physically the same device, but logically defined as two functional entities, wherein the eNB  310  is responsible for LTE Radio Access Network (RAN) operation on the licensed LTE spectrum and the AP  305  is responsible for operation in the unlicensed (e.g. mmW) band. 
     The AP  305  may introduce additional logical interfaces to Mobility Management Entity/Serving Gateway (MME/S-GW)  315  and  317  and neighboring Access Point (AP) nodes  320 . These additional interfaces may include a Sx interface  330  which may support configuration of the AP  305  from the MME/S-GW node  315  or  317 . In another example, Sx  330  may be further split into a Sx-MME and Sx-U, where Sx-MME is the interface to the MME node and Sx-U is the interface to the S-GW node of the MME/S-GW node  315  or  317 . In another example, a S1  332  interface may be extended with additional configuration messages or parameters to allow operation and management of the AP node  305 . 
     Another example interface that may be included is an AP-X2 interface  335  between the AP nodes. This may be a logical interface between the AP nodes  305  and  320 , which may be further split into AP-X2-Control and AP-X2-Data to carry control plane and user plane messaging, respectively, between the AP nodes  305  and  320 . The eNB  310  may communicate with another eNB  312  via X2 interface  339 . 
     The architecture  300  may further include an AP Management System (AP-MS)  350  which provides an operations, administration and maintenance (OAM) interface  355  to support startup, initial configuration and management of AP nodes  305  and  320 . 
       FIG. 4  shows an overall E-UTRAN architecture  400  with APs  405  and  407  in a non-co-located deployment. The APs  405  and  407  are in communication with eNBs  410  and  412 , all of which are in communication with MME/S-GWs  415  and  417 . The AP nodes  405  and  407  may have the following logical interfaces to the other nodes in the E-UTRAN sub-system. These may include a Sx interface  430  which may support configuration of the APs  405  and  407  from the MME/S-GW nodes  415  and  417 . In another example, the Sx may be further split into Sx-MME and Sx-U, where Sx-MME is the interface to the MME and Sx-U is the interface to the S-GW of the MME/S-GW nodes  415  and  417 . The Sx may be equivalent to a S1-C interface for AP nodes. In another example, a S1  432  interface may be extended with additional configuration messages or parameters to allow operation and management of the AP nodes  405  and  407 . In particular, the MME may have a direct interface to the AP nodes to configure the WTRU context to the AP node, bearer context, quality fo service (QoS) profiles, and the like. 
     The APs  405  and  407  may have an AP-X2 interface  335  between them. This interface may be further split into AP-X2-Control and AP-X2-Data to carry control plane and user plane messaging respectively between the AP nodes  405  and  407 . The AP-X2  435  link may be for neighbor interference management and 802.11 band (re-)configuration. The X2′  437  may define the logical interface between eNB  412  and AP  405 , for example. It may be split into X2′-C and X2′-U interfaces. The eNB  410  may communicate with another eNB  412  via X2 interface  439 . 
     These defined logical interfaces may operate over any physical interfacing options, and may be configured to operate over existing or new Layer  2  or Layer  3  messaging (e.g. IP or GTP). 
     The APs may obtain configuration from the AP-MS using two different methods which are applicable to both the co-located and non-co-located examples described herein. One example method uses a direct interface to the AP-MS. In this scenario, the AP may have a connection to the IP network, i.e., at startup the AP node may be connected to the IP network and maintain an independent IP address. This allows for a direct interface to the AP-MS. Another example method uses an eNB interface to the AP-MS. In this scenario, the AP does not have a direct connection to the IP network, but has a cellular interface to obtain initial configuration from the eNB. The eNB connects to the AP-MS and provides configuration to the AP node when it attaches to the network using the cellular connection. The AP node could either directly or indirectly, (through the eNB), connect to the rest of the E-UTRAN components. 
       FIG. 5  shows an example overall E-UTRAN architecture  500  with APs  505  and  507  in a non-co-located deployment. The APs  505  and  507  are in communication with eNBs  510  and  512 , all of which are in communication with MME/S-GWs  515  and  517 . The AP nodes  505  and  507  may have the following logical interfaces to the other nodes in the E-UTRAN sub-system. These may include a Sx interface  530  which may support configuration of the APs  505  and  507  from the MME/S-GW nodes  515  and  517 . In another example, the Sx may be further split into Sx-MME and Sx-U, where Sx-MME is the interface to the MME and Sx-U is the interface to the S-GW of the MME/S-GW nodes  515  and  517 . In another example, a S1  532  interface may be extended with additional configuration messages or parameters to allow operation and management of the AP nodes  505  and  507 . The X2′  537  may define the logical interface between eNB  512  and AP  505 , for example. The eNB  510  may communicate with another eNB  512  via X2 interface  539 . 
     The APs  505  and  507  may an AP-X2 interface  535  between them. This interface may be further split into AP-X2-Control and AP-X2-Data to carry control plane and user plane messaging respectively between the AP nodes  505  and  507 . 
     Described herein is the X2′ interface. This interface may define the logical interface between eNB and AP as shown herein above in  FIGS. 4 and 5 . It may be split into X2′-C and X2′-U interfaces. In both the co-located and non co-located deployments, the X2′-C is a logical interface between the AP and the eNB for exchanging control signaling for management, co-ordination and configuration between the eNB and the AP nodes. For example, the X2′-C messaging could be carrying configuration for initial setup. 
     In an example method, the X2′-C messaging may be exchanged using radio resource control (RRC) protocol over wired link or wireless cellular link. This may require extension of RRC messages or new messages to support or enable bring-up, operation and management of AP nodes. 
     In another example method, the AP may send a RRC connection request message to get a connection with the eNB. The RRC connection request method may have an additional message indicator to specify if the AP requires resources for the backhaul data-plane or not. The AP may further indicate capabilities including the back-haul and access capabilities. The RRC connection setup message may be extended to include the configuration parameters for AP operation in access link, basic service set ID (BSSID), 802.11 options, and the like. Further additional messaging may be added to authenticate the AP and exchange security parameters required for AP operation. The X2′-C messaging may be initially sent over RRC signaling using the cellular connection and later transitioned to control messaging over the backhaul RAT used. The X2′-C interface may be a wired interface to carry control signaling over a wired link. 
     Alternatively, the X2′-C messaging may be exchanged using new signaling protocol sent over a GTP over IP link over a generic L 2 /L 1  stack, (wired or wireless). The X2′-C protocol may carry access configuration parameters and WTRU authentication parameters. 
     Described herein is the X2′-U interface between the eNB and the AP node. In the non co-located deployment, the X2′-U may be a logical interface for data-plane messaging between the eNB and the AP node. In an example, the X2′-U interface may carry radio link control (RLC) packet data units (PDUs) or medium access control (MAC) service data units (SDUs) that need to be sent to the WTRU through the AP node. The X2′-U interface may be a per-WTRU, per-Radio Bearer (or EPC bearer) per WTRU, or for only per UE interface. 
     The X2′-U interface may be implemented using wired or wireless backhaul. The backhaul may be implemented using GTP over IP network over any L 2 /L 1  stack. In an example, the back-haul may use cellular data plane. In another example, the backhaul may use a wireless mesh architecture with multiple hops between the eNB and the AP node. In another example, the X2′-U messaging may be used to carry RLC user-plane traffic for individual WTRUs over GTP over User Datagram Protocol (UDP) over IP. 
     Described herein is the AP gateway (GW) node.  FIG. 6  shows an example E-UTRAN architecture  600  with an AP  605  in a co-located deployment with an AP GW node  609 . In another example, the AP  605  may be co-located as described herein above with an eNB  610 . The eNB  610  may communicate with another eNB  612  via a X2 interface  639 , and with MME/S-GW  615  and  617  via S1 interfaces  632 . The AP  605  may communicate with AP GW  609  and MME/S-GW  615  and  617  via Sx interfaces  630 . The AP may use the Sx interface  630 , to communicate between the AP  605  and the EPC to support a large number of APs in a scalable manner, for example, AP  607 . The AP GW  609  serves as a concentrator for the C-Plane, specifically the Sx-MME interface. The Sx-U interface from the AP  605  may be terminated at the AP GW  609 , or a direct logical U-Plane connection between the eNB  610  and the S-GW of MME/S-GW  615  or  617  may be used. 
       FIG. 7  shows an example overall E-UTRAN architecture  700  with an AP  705  in a non-co-located deployment with AP-GW  709 . AP  705  and AP  707  are in communication with an eNB  710  via an X2′ interface  737  and are in communication with each other via an AP-X2 interface  738 , i.e. the data from  705  and  707  may be routed either directly back to an eNB via X2′ or though a multi-hop connection via AP-X2 and then to X2′. The eNB  710  may communicate with an eNB  712  via an X2 interface  739  and with MME/S-GW  715  and  717  via a S1 interface  732 . The AP GW  709  may communicate with AP  705  and  707  and MME/S-GW  715  and  717  via an Sx interface  730 . 
     Described herein are example deployment structures using 802.11 basic service set (BSS)/extended service set (ESS) configurations. The 802.11 APs associated with a particular eNB may form an ESS and share the same service set ID (SSID). The APs and their associated WTRUs, (also called stations—STAs), form a Basic Service Set (BSS) and are identified by a unique BSSID. The BSSs are connected to each other via the distribution system, which also may connect them to the internet. 
       FIG. 8  shows an example system  800  including a collection of BSSs forming an ESS and how the ESS structure relates to the hybrid cellular-WLAN architecture. In particular, an ESS  705  may include an eNB  810  that is connected to Internet  808 . The eNB  810  may be connected to a WTRU  815 , and to AP  820  and AP  830  via an X2′ interface  812 . The AP  820  may have a corresponding BSS  822  which may include WTRUs  825  and  827  in communication with AP  820 . The AP  830  may have a corresponding BSS  832  which may include WTRU  835  in communication with AP  830 . 
     A few variations may be possible as far as WTRU-to-AP mutual authentication and communication security are concerned. In an example, the AP and the WTRU authenticate to each other and exchange security keys based on the original 802.11 procedure, but with the authentication and key exchange messages flowing from the AP to the authentication server, (residing in the eNB), over the X2′ interface. In another example, the mutual authentication procedure may be simplified because the WTRU and the AP have secure connections to the eNB. This allows the authentication procedure to be truncated to a simple two-message challenge text/response exchange, or may be skipped altogether. 
       FIG. 9  shows a user-plane protocol stack view  900  for a WTRU  901 , AP  902  and eNB  903 . This protocol stack view  900  may apply to both the co-located and non-co-located deployments. The WTRU protocol stack  905  may include a Packet Data Convergence Protocol (PDCP) entity  910 , a radio link control (RLC) entity  911 , a LTE MAC entity  912 , a LTE PHY entity  913 , a WLAN MAC entity  914  and a WLAN PHY entity  915 . The AP protocol stack  920  may include a Relay entity  921 , a WLAN MAC entity  922 , a WLAN PHY entity  923 , a GPRS Tunneling protocol user plane (GTP-U) entity  924 , an UDP entity  925 , an IP entity  926 , an L 2  entity  927  and an L 1  entity  928 . The eNB protocol stack may  930  may include a PDCP entity  931 , a RLC entity  932 , a LTE MAC entity  933 , a LTE PHY entity  934 , a GTP-U entity  935 , an UDP entity  936 , an IP entity  937 , an L 2  entity  938  and an L 1  entity  939 . 
     The user-plane protocol stack between the WTRU  901  and the AP  902  may use the 802.11 MAC  914 ,  922  and the 802.11 PHY layers  915 ,  923 , respectively, for the WLAN link  940 . The user-plane protocol stack between the AP  902  and the eNB  903  may use GTP-U  924 ,  935 , respectively, for the X2′-U interface  950 . The LTE MAC  912 ,  933  and PHY  913 ,  934  in the WTRU  901  and the eNB  903  may communicate over the Uu interface. 
     The L 1  and L 2  layers on the X2′-U interface are unspecified. Any PHY protocol running over a medium such as, but not limited to, optical fiber, Ethernet, microwave, millimeter wave or cellular-based backhaul and its accompanying Layer-2 protocols may be applicable. 
     Methods and apparatus (i.e., architecture) are described herein to enable tight integration of a 3GPP radio access network (RAN) and an IEEE 802.11 system. To achieve tighter integration, aggregation may be performed at or above MAC layer or below the MAC layer. 
       FIG. 10  shows MAC architecture  1000  for MAC layer aggregation between LTE and IEEE 802.11 air-interfaces. Carrier aggregation with IEEE 802.11 may be transparent to layers above the MAC entity, (for example, radio link control (RLC) entities  1005 , packet data convergence protocol (PDCP) entities  1010 , and the like). The MAC entity or functionality may be split into an upper MAC module  1015 , (or common MAC), an LTE-A lower MAC module/entity  1020  and IEEE 802.11 MAC module/entity  1030 , which may interface with the upper MAC module/entity  1015  via a “glue (WLAN Abstraction) layer or entity”  1040 . The upper MAC module/entity  1015  may hide the details of specific RAT related aspects from layers above the MAC entity. The upper MAC module/entity  1015  may interface with the RLC entities  1005 . An LTE radio resource control (RRC) module/entity  1025  may configure and control the upper MAC module/entity  1015 , along with the LTE-A lower MAC module/entity  1020 , an IEEE 802.11 lower MAC module/entity  1030  and an IEEE 802.11 physical layer/entity (PHY)  1035 . The IEEE 802.11 protocol interactions with LTE layers may be abstracted using the glue layer/entity  1040 . 
     The upper MAC module  1015  may provide a service access point (SAP) to the RLC entities  1005 , map logical channel data to the LTE-A lower MAC module  1020  or the IEEE 802.11 lower MAC module  1030 . Logical channel prioritization (LCP) may be part of the upper MAC module  1015  if performing combined LCP or hybrid LCP options, or may be absent if performing split LCP. 
     LCP may be part of the LTE-A lower MAC module  1020  if performing split LCP, and absent if performing combined LCP or hybrid LCP options. MAC frame processing is implemented by the multiplexing of MAC service data units (SDUs) from one or different logical channels onto transport blocks (TBs) to be delivered to the physical layer on transport channels, and demultiplexing of MAC SDUs from one or different logical channels from TBs delivered from the physical layer on transport channels. The LTE-A lower MAC module  1020  and the IEEE 802.11 lower MAC module  1030  may implement access schemes, channel quality monitoring, link adaptation, modulation and coding scheme (MCS) selection, scheduling information reporting and error correction through hybrid automatic repeat reauest (HARQ)/IEEE 802.11 retransmission. 
     The WLAN abstraction or glue layer/entity  1040  may provide a configuration for the IEEE 802.11 carrier/AP, and abstract details of IEEE 802.11 RAT implementation from LTE. In particular, the glue layer/entity  1040  may hide details specific to 802.11 MAC/PHY, provide interface for user data exchange, provide mechanisms to obtain information related to buffer occupancy, and provide an interface for 802.11 RAT to provide information as to how much data it can potentially transmit within a given time period. 
     The glue layer/entity  1040  may also enable application programming interfaces (APIs) to send and receive both control and data plane aspects. Control plane aspects may include configuration/re-configuration, activation/deactivation, discontinuous reception (DRX), neighbor AP and radio resource management (RRM) measurements, and the like. Data plane aspects may include scheduling related information, (modulation coding scheme (MCS), transmission opportunity (TXOP) per access class (AC), maximum packet size, grant periods and the like), higher layer data handling and associated success/failure indications, discard handling, and the like. The glue layer  1040  may also provide translation between LTE formats and IEEE 802.11 formats, provide and control first-in first-out FIFO data buffers for derandomizing data flows, and execute an LCP algorithm the case of a split LCP. 
     The glue/WLAN Abstraction layer/entity  1040  may also provide details specific to 802.11 MAC/PHY, interface for user data exchange, mechanisms to obtain information related to buffer occupancy, and an interface for 802.11 RAT to provide info as to how much data it can potentially transmit within a given time period. Further, it may provide QoS translation and configuration translation for example related to Measurement configuration etc. 
     Logical channel to transport channel mapping may also be implemented as part of the glue layer  1040 . The IEEE 802.11 carrier may provide another transport channel both as a UL shared channel (UL-SCH) as shown in  FIG. 11  and as a DL-SCH as shown in  FIG. 12 . In particular,  FIG. 11  shows UL transport channels for an LTE and IEEE 802.11 RAT aggregated system  1100  that includes at least a 802.11 UL-SCH  1105  mapped to a dedicated traffic channel (DTCH)  1110  and  FIG. 12  shows DL transport channels for an LTE and IEEE 802.11 RAT aggregated system  1200  that includes at least a 802.11 DL-SCH  1205  mapped to a dedicated traffic channel (DTCH)  1210 . 
       FIG. 13  shows architecture  1300  for MAC aggregation across LTE and IEEE 802.11 RATs. Architecture  1300  illustrates a MAC entity  1305  that service upper layers  1310  and lower layers  1320 . Service to the upper layers  1310  is provided in the form of logical channels that may include a paging control channel (PCCH)  1330 , a multicast control channel (MCCH)  1331 , a multicast traffic channel (MTCH)  1332 , a broadcast control channel (BCCH)  1333 , a common control channel (CCCH)  1334 , a dedicated control channel (DCCH)  1335 , and a dedicated traffic channel ( 1336 ). The upper layers  1310  further include a MAC-control entity  1315 . Service to the lower layers  1320  is provided in the form of transport channels which may include a paging channel (PCH)  1340 , a multicast channel (MCH)  1341 , a broadcast channel (BCH)  1342 , a DL-SCH  1343 , an UL-SCH  1344 , an 802.11 PHY  1345  and a random access channel (RACH)  1346 . 
     The MAC entity  1305  may include a logical channel prioritization (LCP) entity  1350  connected to a (de) multiplexing entity  1352  which in turn is connected to a hybrid automatic repeat request (HARQ) entity  1354  and an IEEE 802.11 transport or HARQ entity  1356 . The MAC entity  1305  may further include a de-multiplexing entity  1358  and a random access control entity  1360 . A control entity  1370  is connected to the LCP  1350 , (de) multiplexing entity  1352 , HARQ  1354 , 802.11 transport entity  1356 , de-multiplexing entity  1358  and random access control entity  1360 . In particular, the 802.11 transport entity  1356  may be perceived to be another HARQ entity from an LTE MAC point of view. The name IEEE 802.11 HARQ is meant to imply that an IEEE 802.11 RAT implements HARQ features such as incremental redundancy/chase combining and the like. The data interface between LTE MAC and IEEE 802.11 is configured so that a transport block may be built by an LTE MAC and provided to an IEEE 802.11 RAT for transmission. A transport block from the 802.11 transport entity  1356  may be transmitted using the 802.11 MAC and PHY layers. 
       FIG. 14  shows a DL protocol stack view  1400  for MAC aggregation across LTE and IEEE 802.11 RATs and  FIG. 15  shows a UL protocol stack view  1500  for below MAC aggregation across LTE and IEEE 802.11 RATs. The DL protocol stack view  1400  includes a PDCP entity  1410 , a RLC entity  1415  and a MAC entity  1420 . The PDCP entity  1410  may include Robust header compression (ROHC) entities  1430  and security entities  1432 . The RLC entity  1415  may include at least segmentation/ARQ entities  1434  and segmentation entities  1436 . The MAC entity  1420  may include an unicast scheduling/priority handling entity  1440  connected to multiplexing entities  1442  . . .  1444 , which in turn are connected to HARQ entities  1450  and an 802.11 transport or HARQ entity  1452 . 
     The UL protocol stack view  1500  includes a PDCP entity  1510 , a RLC entity  1515  and a MAC entity  1520 . The PDCP entity  1510  may include Robust header compression (ROHC) entities  1530  and security entities  1532 . The RLC entity  1515  may include at least segmentation/ARQ entities  1534 . The MAC entity  1520  may include a scheduling/priority handling entity  1540  connected to a multiplexing entity  1542 , which in turn is connected to HARQ entities  1550  and an 802.11 HARQ entity  1552 . 
     For MAC aggregation, MAC may be configured to use a semi-static grant size based on the IEEE 802.11 RAT average data capabilities, or IEEE 802.11 may provide MAC with a data size each TTI that it is capable of transmitting. This data size may be derived based on the IEEE 802.11 protocol. If the 802.11 modem is capable of operating in more than one channel/band simultaneously, (for example, when 802.11n and 802.11ad are operating simultaneously in 802.11 tri-mode device), then a separate 802.11 Transport Entity may be defined for each 802.11xx that is active, (both in uplink and downlink). 
     Described herein is the glue layer or WLAN abstraction layer. The glue layer or entity provides an abstraction between the LTE AS and the IEEE 802.11 RAT. The logical entities of the glue layer include a user plane and a control plane/LTE service management entity (SME). The user plane may be responsible for data buffering, flow control, quality of service mapping, scheduling feedback, (MCS, TXOP per access class (AC), grant size, packet size, and the like), discard handling and execution of an LCP algorithm in the case of split LCP. The control plane/LTE access stratum-service management entity (AS-SME) may be responsible for configuration/reconfiguration of an IEEE 802.11 carrier, activation/deactivation, DRX configuration and radio resource management (RRM) measurement configuration. 
       FIG. 16  shows an example architecture  1600  for MAC layer aggregation across LTE and IEEE 802.11 RATs by using a glue layer control entity  1605 , (in the control plane) and a glue layer data entity  1610 , (in the user plane). The glue layer control entity  1605  may include a mapping function  1606  and a LTE SME entity  1608 . The glue layer data entity  1610  may include a mapping function  1612  and a buffer management entity  1614 . The LTE SME entity  1608  is connected to the mapping function  1612 . 
     Architecture  1600  may further include a LTE RRC  1620  connected to glue layer control entity  1605  and to LTE PDCP/RLC/Upper MAC entity  1625 , which in turn receives data from the application data plane  1627 . The LTE PDCP/RLC/Upper MAC entity  1625  is also connected to the glue layer data entity  1610  and a LTE MAC entity  1630 . The glue layer data entity  1610  is further connected to a 802.11 MAC entity  1640 , which in turn is connected to the mapping function  1606  and to a 802.11 PHY entity  1645 . The LTE MAC  1630  is connected to a LTE PHY  1650 . 
     In the glue layer control entity  1605 , the LTE RRC entity  1620  may be extended to allow aggregation of the two RATs, (IEEE 802.11 and LTE). The LTE SME  1608  provides an abstraction to provide a mapping from the LTE configuration to the IEEE 802.11 layer. 
     When carrier aggregation is used for tighter integration of LTE and 802.11 RAT, 802.11 RAT is assumed to be configured as a secondary carrier. LTE may be configured as the primary carrier and may perform all LTE functionalities. 
       FIG. 17  shows an example LTE stack  1700  which may include a LTE AS-SME  1705 . The LTE stack  1700  may include a RRC entity  1710 , a PDCP entity  1715 , a RLC entity  1720 , a MAC entity  1725  and a PHY entity  1730 . For LTE plus IEEE 802.11 carrier aggregation, the LTE AS may act as the SME that interfaces to the IEEE 802.11 MAC layer management entity (MLME). This entity or module  1705  may interact closely with the existing LTE RRC entity  1710 . The LTE AS-SME  1705  may also be viewed as part of an RRC layer or the glue layer. 
     RRC messages received from the network related to a IEEE 802.11 RAT  1740  may be forwarded to the LTE AS-SME  1715  for configuring and maintaining the IEEE 802.11 RAT  1740 , (measurement control, and the like), as required. The LTE AS-SME  1705  may also receive updates from the IEEE 802.11 RAT  1740  and translate them to RRC messages as required to be transmitted to the network. 
     Different methods for configuration of the IEEE 802.11 RAT  1740  may be used depending on the availability of WTRU location information at the network. In an example, location of the WTRU is known to the network with a high degree of precision via methods such as assisted satellite positioning, Cell ID based positioning, observed time difference of arrival, or others. Then, based on its prior knowledge of AP locations and current AP traffic conditions, the network can make a determination of the optimum AP for the WTRU to associate with. All 802.11 RAT pre-data transfer steps including authentication, authorization and key management, traffic stream (TS) setup and association are performed between the 802.11 RAT in the WTRU and the chosen AP through the LTE network. The WTRU may directly start frame exchanges with the AP via contention based or contention free mechanisms. In case of quality of service (QoS) enabled AP and WTRU, multiple frames may be transmitted in an efficient manner via polled or contention-based transmission opportunity (TXOP). 
     In another example, when WTRU location is unknown or known with insufficient precision, the 802.11 RAT in the WTRU is provided a list of channels to scan and obtain a list of reachable APs that are available on them by the eNB via cellular link. This instruction appears as a Beacon Request to the 802.11 RAT, which then responds with the received channel power indicator (RCPI), received channel to noise indicator (RSNI), receiver antenna ID and timing synchronization function (TSF) offset of each observed BSS. The reported information may result from passive scanning of beacon or measurement pilot frames or from probe responses received in response to a probe request to neighboring APs. The LTE AS-SME then interprets and translates this information to a RRC report which is sent to the network. Based on the reported information and other information such as AP traffic loads that is already known, the network may choose one of the APs and recommend it to the WTRU to associate with. Similar to the first example, all pre-data transfer steps including authentication, authorization and key management, TS setup and association are performed between the 802.11 RAT in the WTRU and the chosen AP through the LTE network. The WTRU may directly start frame exchanges with the AP at the next transmission opportunity (TXOP). Measurement configuration and reports are described herein below. 
     A variation of the second example involves the eNB supplying the 802.11 RAT in the WTRU with the SSID of a preferred ESS. Then the WTRU transmits a Probe Request frame including the specified SSID. In response, only those APs that receive the Probe Request and share the particular SSID would respond with Probe Response frames that would enable the WTRU to perform signal strength measurements as described above. This reduces the amount of time the WTRU has to wait to receive all Probe Responses from neighboring APs, since APs that are not part of the ESS would not respond to the Probe Request frame. A further optimization of this process is possible due to cellular layer controls as follows. Upon receiving the Probe Request from the WTRU, APs that are a part of the corresponding ESS report to the eNB their traffic load and other parameters such as signal strength of the received Probe Request. Based on this information the eNB directs all or some of the APs to respond with Probe Response frames and also schedules their transmission. The WTRU is also notified about the number of Probe Response frames to expect. This will reduce the scan time as the APs do not have to contend for channel access to transmit the Probe Responses and the WTRU need not wait till the end of the probe response timeout period to receive all responses. 
     In another example, an IEEE 802.11 AP related configuration may be provided by the network to a WTRU as part of an RRC message. This message may be forwarded to the LTE AS-SME, which uses the provided configuration information to configure an IEEE 802.11 RAT. This message may consist of one or more IEEE 802.11 service set identifiers (SSIDs), channel(s) used by AP(s) under consideration, and other similar details required by IEEE 802.11 RAT to associate with an IEEE 802.11 AP. The IEEE 802.11 RAT in a WTRU may be instructed to perform scanning and obtain details of APs that are available. The IEEE 802.11 RAT may provide this information to the LTE AS-SME, which may interpret and translate this information to an RRC report. This message may then be sent to the network. Based on RRM and other admission criteria, the network may then choose one of the APs and recommend it to the WTRU to associate with. After reception of this RRC message via the LTE AS-SME, the IEEE 802.11 RAT may start an association with this particular AP. 
     A mapping function may be provided by the LTE SME entity to translate LTE RRC messaging to IEEE 802.11 control and management functions. 
     Described herein are measurement methods for the 802.11 carrier. The 802.11 carrier is presented to the LTE AS a secondary cell (SCell). As such, measurements of the 802.11 signal strength and quality must be performed to provide the necessary SCell measurements for cell detection and configuration/deletion. 
     The WTRU reports measurement information in accordance with the measurement configuration as provided by the network. The network may provide the measurement configuration applicable for the WTRU in RRC_CONNECTED by means of dedicated signaling, i.e., using the RRCConnectionReconfiguration message. 
     For an IEEE 802.11 channel, the WTRU may be requested to perform intra-frequency measurements of different BSSs that reside on the configured channel, and inter-frequency measurements of identified BSSs on different channels/bands. 
     For all of the measurements on the IEEE 802.11 channel, measurement gaps may be provided to allow the WTRU associated with a BSS to obtain measurements on other BSSs and/or channels. Additionally, if measurement pilots are used by neighbor BSSs, the measurement configuration may include a pattern and the periodicity of measurement pilots, pilot configuration, and the like. Measurement pilots may be designed to support rapid discovery of BSS and neighbor AP signal strengths. They may be transmitted at a configurable interval that is a fraction of the beacon period. 
     Measurement objects and gaps, (configuration elements), may be enhanced to include an 802.11 channel measurement. Measurement objects include objects on which the WTRU would perform measurements. For intra-frequency and inter-frequency measurement, this would map to an 802.11 channel in a certain band. For example, in the industrial, scientific and medical (ISM) 2.4 GHz band, any of the 20 MHz channels, such as channel  1 ,  6 ,  11 , may be configured as a measurement object. Measurement gaps are periods that the WTRU may use to perform measurements. These gaps are configured with the knowledge that the IEEE 802.11 AP may not perform transmissions at these times for the WTRU (i.e., DRX operation in IEEE 802.11). 
     A new RAT-specific IEEE 802.11 measurement object (MeasObject80211) as shown in Table 1 may be added to provide the following additional configuration to allow IEEE 802.11 measurements as a neighbor and/or secondary cell. IEEE 802.11 measurement objects (MeasObject80211) may additionally include configuration to measurement neighbor cells (BSSs), including BSS list in the channel, frequency of measurement pilot and offset relative to beacon of serving AP, beacon periodicity and offset relative to beacon of serving AP, and other configuration details for measuring neighbor BSSs. 
     
       
         
           
               
             
               
                 TABLE 1 
               
               
                   
               
             
            
               
                 -- ASN1START 
               
            
           
           
               
               
            
               
                 MeasObject80211 ::= 
                 SEQUENCE { 
               
               
                   carrierFreq 
                   ARFCN-Value80211, 
               
               
                   allowedMeasBandwidth 
                   AllowedMeasBandwidth, 
               
               
                   neighCellConfig 
                   NeighCellConfig, 
               
            
           
           
               
               
               
            
               
                   offsetFreq 
                   Q-OffsetRange 
                 DEFAULT dB0, 
               
            
           
           
               
               
            
               
                   -- Cell list 
                   
               
            
           
           
               
               
               
               
            
               
                   cellsToRemoveList 
                   CellIndexList 
                 OPTIONAL, 
                 --Need ON 
               
               
                   cellsToAddModList 
                   CellsToAddModList 
                 OPTIONAL, 
                 --Need ON 
               
            
           
           
               
               
            
               
                   -- Black list 
                   
               
            
           
           
               
               
               
               
            
               
                   blackCellsToRemoveList 
                   CellIndexList 
                 OPTIONAL, 
                 --Need ON 
               
               
                   blackCellsToAddModList 
                   BlackCellsToAddModList 
                 OPTIONAL, 
                 -- Need ON 
               
            
           
           
               
               
            
               
                 } 
                   
               
               
                 CellsToAddModList ::= 
                 SEQUENCE (SIZE (1..maxCellMeas)) OF CellsToAddMod 
               
               
                 CellsToAddMod ::=  SEQUENCE { 
                   
               
               
                   cellIndex 
                   INTEGER (1..maxCellMeas), 
               
               
                   BSS         BSS-CONFIG 
                   
               
               
                   cellIndividualOffset 
                 Q-OffsetRange 
               
               
                 } 
                   
               
               
                 BlackCellsToAddModList ::= 
                 SEQUENCE (SIZE (1..maxCellMeas)) OF BlackCellsToAddMod 
               
               
                 BlackCellsToAddMod ::=  SEQUENCE { 
                   
               
               
                   cellIndex 
                   INTEGER (1 maxCellMeas), 
               
            
           
           
               
            
               
                   BSS         BSS-CONFIG 
               
               
                 } 
               
            
           
           
               
               
            
               
                 MeasCycleSCell-r10 ::= 
                 ENUMERATED {0,5,10,20,30,xxxx} [Measurement period when  
               
            
           
           
               
            
               
                 the 802.11 carrier is configured as a secondary cell. Time in ms] 
               
               
                 } 
               
               
                   
               
            
           
         
       
     
     In order to facilitate neighbor cell measurements, the AP may send the WTRU a Beacon Request action frame including but not limited to the following parameters: channel identifier, Beacon Interval, TSF Offset, measurement duration. At the end of the measurement duration the WTRU responds with a Beacon Report action frame with BSSIDs of all observed BSSs on the channel, (if wildcard BSSID was used by serving AP in Beacon Request), and corresponding measurements including, but not limited to, the Received channel Power Indicator (RCPI), the Received Signal to Noise Indicator (RSNI), and receiver antenna ID.  FIG. 18  shows the Measurement Report Field format  1800  for a Beacon Report which contains a RCPI  1805  and RSNI  1810 . 
     The neighbor BSS Beacon periodicity and offset reported by the AP may enable the WTRU to calculate the Target Beacon Transmission Time (TBTT) of the neighbor AP. This enables the WTRU to make a determination of when to switch channels if the measurement corresponds to a non-operating channel. The AP will not transmit to the WTRU during this interval. In order to avoid the situation of all associated WTRUs simultaneously listening to Beacon transmission on a non-operating channel, which would preclude any data transmission on the BSS over that duration, the AP may schedule the measurement cycles of the WTRUs in such a way that they do not all coincide in time. 
     The use of Measurement Pilot frames, which are action frames including most of the information present in the Beacon frame and transmitted more frequently than Beacon frames, allows for rapid discovery of neighbor BSSs and also may enable neighbor BSS measurements with higher periodicity. The serving AP may signal the periodicity and offset of neighbor AP Measurement Pilot frames, when they are used, instead of Beacon frames, thereby enabling smaller measurement latency. 
     In case of event-based triggering, the 802.11 carrier may be configured to report measurements when the measurement goes over A 3 , (neighbor measurement is better than primary cell by an offset), A 6 , (neighbor measurement is better than secondary cell by an offset threshold), or new events might need to be defined to allow 802.11 RAT to additionally indicate channel utilization threshold, and the like. 
     The threshold quantities may be defined in information element (IE) IE Threshold80211. The threshold configuration parameters may include the following values, including but not limited to the RSSI, channel utilization, number of observed BSSs, and so on. 
       FIGS. 19A and 19B  show an example method  1900  for configuring 802.11 measurements via a LTE AS, and for performing and reporting those measurements back to the eNB. As shown, the method  1900  operates or interacts between an eNB  1905 , 802.11 BSS  1910 , and a WTRU  1915  that may include a LTE AS-SME  1917  and an 802.11 MLME  1919 . A new measurement object type for 802.11 measurements may be introduced that contains the SSID and/or BSSID and channel list for the 802.11 systems compatible with LTE, as would be configured by the service providers. In addition, the reportConfig80211 configuration element may be introduced to configure event triggered and/or periodic measurement. 
     The eNB  1905  may send a measurement configuration message to the LTE AS-SME  1917  ( 1920 ). A message confirmation message may be sent by the LTE AS-SME  1917  to the eNB  1905  to confirm receipt of the measurement confirmation message for the 802.11 SCell ( 1922 ). The LTE AS-SME  1917  may then create and send an MLME-SCAN.request ( 1924 ) to initiate searching for infrastructure BSS&#39;s that belong the service providers system ( 1926 ). Once the 802.11 MAC/PHY in the WTRU detects a valid 802.11 SCell, it may send the results to the LTE AS-SME  1917  ( 1928 ). The LTE AS-SME  1917  may then initiate measurements by sending a MLME-MEASURE request to the 802.11 MLME  1919  ( 1930 ). The measurements are taken ( 1932 ) and a confirmation message may be sent to the LTE AS-SME ( 1934 ). The LTE AS-SME  1917  may then process the measurement results ( 1936 ) and send a measurement report to the eNB  1905 , (for example, the RRC), ( 1938 ). The measurement report may be sent every measurement period or based on event reporting, (depending on configuration). 
     Based on these measurements, the eNB  1905  may configure an appropriate secondary cell (SCell) ( 1940 ) and send a RRCConnectionReconfiguration message to the LTE AS-SME  1917  initiate 802.11 association ( 1942 ). The LTE AS-SME  1917  may send a MLNE.Associate message to the 802.11 MLME  1919  ( 1944 ), which in turn may start the association and authentication process between the LTE AS-SME  1917  and the 802.11 MLME  1919  ( 1946 ). The eNB  1905  may send a MAC SCell Activation Control Element message to the LTE AS-SME  1917  to activate the SCell ( 1948 ). Data transfer between the 802.11 BSS  1910  and the 802.11 MLME may then take place ( 1950 ). 
     The measurement procedures may continue and may be used to trigger SCell addition/deletion, (activation/deactivation). For example, the LTE AS-SME  1917  may initiate measurements by sending a MLME-MEASURE request to the 802.11 MLME  1919  ( 1952 ). The measurements are taken ( 1954 ) and a confirmation message may be sent to the LTE AS-SME ( 1956 ). The LTE AS-SME  1917  may then process the measurement results ( 1958 ) and send a measurement report to the eNB  1905 , (for example, the RRC), ( 1960 ). Based on the measurement report, the eNB  1905  may send a MAC SCell Deactivation Control Element message ( 1962 ). 
       FIG. 20  shows an example method for LTE AS-SME measurement processing  2000 . In general, the LTE AS-SME measurement processing ensures that LTE RRC measurement entity receives measurement reports at the Layer  1  reporting interval. Typically this may be a 200 msec interval, (Tmeasurement_period_80211=200 msec). As 802.11 beacons are detected by the 802.11 MAC/PHY, the Beacon Reports are sent to the LTE AS-SME and processed. The procedure provides averaging for the RCPI and RSNI. Once the measurement period has expired, RCPI and RSNI are mapped to the RSRP and RSRQ measurements, respectively. As an alternative, the RRC signaling may be updated for an 802.11 measurement report and contain the RCPI and RSNI results directly. As another feature of the LTE AS-SME measurement processing, the number of Beacon Reports in the averaging interval may be counted. If too few Beacon Reports (MeasurementCount&lt;Min80211Measurements) are received, it may be assumed that the channel may be too congested. In this case the minimum RCPI and RSNI are assumed such that the channel may be deemed unfavorable. 
     The parameters are initialized to zero ( 2005 ). This may include setting the AverageRCPI, AverageRSNI, Tmeasure and MeasurementCount to zero. The parameter Tmeasure is a timer of for layer one measurement reporting and the parameter MeasurementCount tallies the number of reports received in the averaging interval. If the timer is still running ( 2010 , yes), measurements are taken and sent to the LTE AS-SME. The LTE AS-SME may then compute the AverageRCPI, and AverageRSNI ( 2015 ). The parameters MeasurementCount and Tmeasure are also incremented. If the timer has expired ( 2010 , no), it is determined if the number of measurements made, (as counted by MeasurementCount), is less than the minimum threshold ( 2020 ). The RCPI and RSNI are set to zero if MeasurementCount is lower than the threshold. The RCPI and RSNI are then mapped to the RSRP and RSRQ measurements, respectively ( 2025 ). The measurement report may be sent to the eNB via RRC signaling. 
     Described herein is 802.11 carrier management and in particular, adding and removing 802.11 carriers.  FIGS. 21A and 21B  show an example flowchart  2100  for addition and removal of the 802.11 carriers without cellular assistance. In particular,  FIGS. 21A and 21B  show cellular integration with 802.11 initial mobility domain association. The decision to add an 802.11 carrier may be made by the eNB, based on considerations such as network load or to switch traffic corresponding to a certain quality of service (QoS) Class Identifier (QCI). The choice of which AP to associate with for a WTRU, when multiple APs are within its communication range, may be also made by the eNB. 
     Initially, a WTRU  2103  may be attached to the network ( 2109 ). At system start-up an AP  2105  may be configured by its serving eNB  2107  with operational parameters, (such as SSID, Beacon Interval, authentication and security procedures, operational band in case of multi-mode AP, channel number, and the like), via X2′ messaging ( 2110 ). The eNB  2107  may then inform the WTRU  2103  to be ready for 802.11 carrier addition ( 2112 ). This may trigger activation of proximity indication sensing by the WTRU  2103  or energizing its 802.11 transceiver ( 2114 ). The 802.11 radio may be generally in powered off state to conserve power. 
     The WTRU may send an “entering” proximity indication when it determines it may be near an AP, (based on autonomous search procedures). The proximity indication may include the BSSID and channel number used during previous session. The eNB may configure the WTRU with relevant measurement configuration including the channel number, (in case it has changed since the WTRU&#39;s last visit), and the target beacon transmission time (TBTT), so that the WTRU may minimize its channel scan time. These steps may not be performed in case the WTRU has not previously visited the BSS. 
     In case proximity indication may be not triggered or if the AP linked to the proximity indication may be non-useable, the eNB may configure the WTRU with a list of channels and the corresponding TBTTs for the WTRU to scan ( 2116 ). 
     The WTRU may scan the indicated channels for Beacon and Measurement Pilot frames. Measurement pilots may be designed to support rapid discovery of BSS and neighbor AP signal strengths. They may be transmitted at a configurable interval that may be a fraction of the beacon period. The WTRU  2103  may send a Measurement Report that may include a list of BSSIDs of observed APs and their corresponding signal quality in terms of received channel power indicator (RCPI), received signal to noise indicator (RSNI) or some other pre-configured measure ( 2118 ). The eNB  2105  may then respond with the chosen AP from the list sent by the WTRU  2103  ( 2120 ). This choice may be based on parameters such as link quality at the WTRU and traffic load at the APs. The authentication and security procedures used by the AP may also be included in the message to the WTRU. 
     The WTRU  2103  and AP  2105  may undergo beamforming training if operating as part of a directional multi-gigabit (DMG)BSS, (operational frequency greater than 45 GHz) ( 2122 ). The WTRU  2103  may then perform authentication ( 2124 ), association ( 2126 ), security key exchange ( 2128 ), and QoS resource allocation ( 2130 ) with the indicated/target AP  2105 . The indicated/target AP  2105  may inform the eNB  2105  of successful WTRU association and QoS allocation ( 2132 ). Data transmission proceeds between the WTRU  2103  and the AP  2105  for the chosen QoS classes. 
     The 802.11 carrier may be deleted by the WTRU when instructed to do so by the eNB by transmitting a disassociate frame to the AP, or when it moves outside the communication range of the AP, (indicated by missed beacon frames). In either case, carrier deletion may be reported to the eNB. 
       FIG. 22  shows an example flowchart  2200  for addition and removal of the 802.11 carriers without cellular assistance. In particular,  FIG. 22  shows cellular-assisted initial mobility domain association. The procedure to add 802.11 carriers may be considerably simplified due to the prior establishment of secure links from an eNB  2205  to a WTRU  2203  ( 2210 ) and from the eNB  2205  to an AP  2207 . The WTRU  2203  may use proximity indication processing as described herein above ( 2212  and  2214 ). The eNB  2205  may configure the WTRU  2203  with relevant measurement configuration including a list of channels as described herein above ( 2216 ). 
     The WTRU  2203  may scan the indicated channels for Beacon and Measurement Pilot frames. Measurement pilots may be designed to support rapid discovery of BSS and neighbor AP signal strengths. They may be transmitted at a configurable interval that may be a fraction of the beacon period. The WTRU  2203  may send a Measurement Report that may include a list of BSSIDs of observed APs and their corresponding signal quality in terms of received channel power indicator (RCPI), received signal to noise indicator (RSNI) or some other pre-configured measure ( 2218 ). The eNB  2205  may then respond with the chosen AP from the list sent by the WTRU  2203  ( 2220 ). 
     The secure link from the WTRU  2203  to the AP  2207  through the eNB  2205 , (that follows cellular authentication procedures), allows the WTRU-to-AP authentication procedure to be truncated or even eliminated. Also, Packet Data Convergence Protocol (PDCP) layer security provided by the cellular network obviates the need for 802.11 key exchange and security procedures as shown in  FIG. 21 . 
     Post target AP identification by the eNB, possible beamforming training in DMG BSS ( 2222 ), association processing ( 2224 ) and QoS resource request processing may be accomplished by messages between the WTRU  2203  and the AP  2207  transmitted through the eNB  2205 . The WTRU  2203  and the AP  2207  mutually authenticate each other by means of challenge query and response messages that have been previously delivered to each node by the eNB  2205  ( 2225 ). This reduces the authentication procedure to a two-message exchange. The target AP  2207  may inform the eNB  2205  of successful WTRU association and QoS allocation ( 2226 ). Data transmission may proceed between the WTRU  2203  and the AP  2207  for the chosen QoS classes ( 2228 ). 
       FIG. 23  shows an example flowchart  2300  for cellular-assisted initial mobility domain association without WLAN authentication. Secure links from an eNB  2305  to a WTRU  2303  ( 2310 ) and from the eNB  2305  to an AP  2307  are in existence. The WTRU  2303  may use proximity indication processing as described herein above ( 2312  and  2314 ). The eNB  2305  may configure the WTRU  2303  with relevant measurement configuration including a list of channels as described herein above ( 2316 ). 
     The WTRU  2303  may scan the indicated channels for Beacon and Measurement Pilot frames. Measurement pilots may be designed to support rapid discovery of BSS and neighbor AP signal strengths. They may be transmitted at a configurable interval that may be a fraction of the beacon period. The WTRU  2303  may send a Measurement Report that may include a list of BSSIDs of observed APs and their corresponding signal quality in terms of received channel power indicator (RCPI), received signal to noise indicator (RSNI) or some other pre-configured measure ( 2318 ). The eNB  2305  may then respond with the chosen AP from the list sent by the WTRU  2303  ( 2320 ). As described herein above, the secure link from the WTRU  2303  to the AP  2307  through the eNB  2305  allows the WTRU-to-AP authentication procedure to be truncated or even eliminated. 
     Post target AP identification by the eNB  2305 , possible beamforming training in DMG BSS ( 2322 ), association processing ( 2324 ) and QoS resource request processing may be accomplished by messages between the WTRU  2303  and the AP  2307  transmitted through the eNB  2305 . The mutual authentication procedure may be eliminated due to pre-authentication of the WTRU  2303  and the AP  2307  to the eNB  2305  and PDCP-level encryption already in use at the cellular layer. The target AP  2307  may inform the eNB  2305  of successful WTRU association and QoS allocation ( 2326 ). Data transmission may proceed between the WTRU  2203  and the AP  2307  for the chosen QoS classes ( 2328 ). 
     Described herein are the messaging details. The function of the WLAN Abstraction layer may be to map the above configuration into 802.11 configurations. Configuration parameters for adding an AP via RRC configuration messages are shown as an example. In particular, a RRC Reconfiguration message with information element (IE) Scell-80211-AddMod element would map to request to associate with a certain 802.11 channel, BSS, and with provided MAC configuration parameters. Scell-80211 Remove would map to request to disassociate with an 802.11 channel. 
     In an example, a new element may be added to the SCellToAddMod-r10 IE to include an 802.11 carrier as shown in Table 2. 
     
       
         
           
               
               
             
               
                 TABLE 2 
               
               
                   
               
             
            
               
                 SCellToAddMod-r10 ::= 
                  SEQUENCE { 
               
               
                    sCellIndex-r10 
                            SCellIndex-r10, 
               
               
                    cellIdentification-r10 
                      SEQUENCE { 
               
               
                       physCellId-r10 
                              PhysCellId, 
               
               
                       dl-CarrierFreq-r10 
                            ARFCN-ValueEUTRA 
               
            
           
           
               
            
               
                    } 
               
            
           
           
               
               
            
               
                  802.11Carrier  
                 SEQUENCE { 
               
               
                       channelMHz 
                   ARFCN-Value80211 
               
            
           
           
               
            
               
                 } 
               
               
                 ARFCN-Value80211 information element 
               
               
                 -- ASN1START 
               
            
           
           
               
               
            
               
                 ARFCN-Value80211 ::= 
                      INTEGER (0..maxEARFCN80211) 
               
            
           
           
               
            
               
                 -- ASN1STOP 
               
               
                   
               
            
           
         
       
     
     Common radio resource configuration for 802.11 may require extension of RadioResourceConfiguration IEs as shown in the example in Table 3. 
     
       
         
           
               
             
               
                 TABLE 3 
               
               
                   
               
             
            
               
                 RadioResourceConfigCommonSCell-r10 ::= SEQUENCE { 
               
               
                     -- DL configuration as well as configuration applicable for DL and UL 
               
            
           
           
               
               
            
               
                      nonUL-Configuration-r10 
                        SEQUENCE { 
               
            
           
           
               
               
               
            
               
                   
                 -- 1: Cell characteristics 
                   
               
               
                   
                 dl-Bandwidth-r10 
                        ENUMERATED {n6, n15, n25, n50, 
               
            
           
           
               
            
               
                 n75, n100}, 
               
            
           
           
               
               
               
            
               
                   
                 -- 2: Physical configuration, general 
                   
               
               
                   
                 antennaInfoCommon-r10 
                        AntennaInfoCommon, 
               
               
                   
                 mbsfn-SubframeConfigList-r10 
                     MBSFN-SubframeConfigList   OPTIONAL, 
               
            
           
           
               
            
               
                     -- Need OR 
               
            
           
           
               
               
               
            
               
                   
                 -- 3: Physical configuration, control 
                   
               
               
                   
                 phich-Config-r10 
                        PHICH-Config, 
               
            
           
           
               
               
            
               
                   
                 -- 4: Physical configuration, physical channels 
               
            
           
           
               
               
               
            
               
                   
                 pdsch-ConfigCommon-r10 
                        PDSCH-ConfigCommon, 
               
               
                   
                 tdd-Config-r10 
                            TDD-Config 
               
            
           
           
               
            
               
                            OPTIONAL    -- Cond TDD 
               
            
           
           
               
               
               
            
               
                   
                 80211-Config-XX 
                                80211-Config 
               
            
           
           
               
            
               
                            OPTIONAL 
               
               
                     }, 
               
               
                     -- UL configuration 
               
            
           
           
               
               
            
               
                     ul-Configuration-r10 
                        SEQUENCE { 
               
            
           
           
               
               
               
            
               
                   
                 ul-FreqInfo-r10 
                        SEQUENCE { 
               
            
           
           
               
               
            
               
                            ul-CarrierFreq-r10 
                            ARFCN-ValueEUTRA 
               
            
           
           
               
               
               
            
               
                   
                 OPTIONAL,   -- Need OP 
                   
               
            
           
           
               
               
            
               
                            ul-Bandwidth-r10 
                        ENUMERATED {n6, n15, 
               
            
           
           
               
               
            
               
                 n50, n75, n100}  
                 OPTIONAL,   -- Need OP                                
               
            
           
           
               
               
            
               
                            additionalSpectrumEmission-r10 
                     AdditionalSpectrumEmission 
               
            
           
           
               
               
               
            
               
                   
                 }, 
                   
               
               
                   
                 p-Max-r10 
                            P-Max 
               
            
           
           
               
            
               
                            OPTIONAL,   -- Need OP 
               
            
           
           
               
               
               
            
               
                   
                 uplinkPowerControlCommonSCell-r10 
                     UplinkPowerControlCommonSCell-r10, 
               
            
           
           
               
               
            
               
                   
                 -- A special version of IE UplinkPowerControlCommon may be introduced 
               
            
           
           
               
               
               
            
               
                   
                 -- 3: Physical configuration, control 
                   
               
               
                   
                 soundingRS-UL-ConfigCommon-r10 
                     SoundingRS-UL-ConfigCommon, 
               
               
                   
                 ul-CyclicPrefixLength-r10 
                 UL-CyclicPrefixLength, 
               
            
           
           
               
               
            
               
                   
                 -- 4: Physical configuration, physical channels 
               
            
           
           
               
               
               
            
               
                   
                 prach-ConfigSCell-r10 
                        PRACH-ConfigSCell-r10 
               
            
           
           
               
               
            
               
                     OPTIONAL,   -- Cond TDD-OR 
                   
               
            
           
           
               
               
               
            
               
                   
                 pusch-ConfigCommon-r10 
                     PUSCH-ConfigCommon 
               
            
           
           
               
            
               
                     } 
               
            
           
           
               
               
            
               
                                    OPTIONAL,  
                 -- Need OR 
               
            
           
           
               
            
               
                 .... 
               
               
                 } 
               
               
                   
               
            
           
         
       
     
     The 80211Config-XXX element and associated PhysicalConfigChannelScell80211-Config IE may include 802.11 specific configuration parameters, including but not limited to, channel ID, BSS ID, channel bandwidth, security configuration, (pairwise cipher suite count and pairwise cipher suite list), and AP related parameters, (supported rates, Block acknowledgement configuration, and the like). 
     In addition, the 802.11 configuration elements may also include configuration 80211-MAC-Config element which allows configuration/reconfiguration of 802.11 MAC may include discontinuous reception (DRX) configuration and buffer status report (BSR) configuration. 
     Described herein is QoS mapping. In order to support multiple QoS requirements, different bearers may be set up within the Evolved Packet System (EPS), each being associated with a QoS. Each bearer may have an associated QoS Class Identifier (QCI). Each QCI may be characterized by priority, packet delay budget and acceptable packet loss rate. The QCI label for a bearer determines how it may be handled in the eNB. Nine such QCIs have been standardized along with their associated characteristics. 
     On the other hand, QoS requirements in 802.11 may be met via four access categories (ACs). These are labeled AC_VO, AC_VI, AC_BE and AC_BK. Several different mapping strategies may be possible from cellular QoS to 802.11 QoS, including AC identifiers (ACI)-to-AC mapping, Priority-to-AC mapping and Packet Delay Budget-to-AC mapping. Table 4 shows illustrative mappings from QCI to AC. 
     
       
         
           
               
               
               
               
               
             
               
                   
                 TABLE 4 
               
               
                   
                   
               
               
                   
                   
                 QoS  
                   
                 Wi-Fi 
               
               
                   
                   
                 Class 
                 Access 
                 Multimedia 
               
               
                   
                   
                 Identifier 
                 Category 
                 (WMM) 
               
               
                   
                 Priority 
                 (QCI) 
                 (AC) 
                 designation 
               
               
                   
                   
               
             
            
               
                   
                 1 
                 5 
                 AC_VO 
                 Voice 
               
               
                   
                 2 
                 1 
                   
                   
               
               
                   
                 3 
                 3 
                 AC_VI 
                 Video 
               
               
                   
                 4 
                 2 
                   
                   
               
               
                   
                 5 
                 4 
                 AC_BE 
                 Best Effort 
               
               
                   
                 6 
                 6 
                   
                   
               
               
                   
                 7 
                 7 
                 AC_BK 
                 Background 
               
               
                   
                 8 
                 8 
                   
                   
               
               
                   
                 9 
                 9 
               
               
                   
                   
               
            
           
         
       
     
     QoS differentiation in 802.11 may involve different back-off windows and priorities for the ACs, both of which impact packet latency. But it lacks procedures resulting in different packet error rates for the ACs. This may be affected by assigning different retransmission attempt limits for each AC, according to its packet error rate requirement. These parameters may be pre-configured at the AP and the WTRU, and may be chosen so that the 802.11 packet error rates for the ACs correspond to those for LTE ACIs. 
     Described herein is DRX configuration. Typical EUTRA DRX-Config may support configuration of DRX for 802.11 carriers. The 802.11 carrier may be configured, (via WLAN Abstraction Layer), to ensure that either a contention period or a power save multi-poll (PSMP) frame may be starting in the channel when any such WTRU comes out of a DRX period for the 802.11 carrier. Note that WTRU may be still required to maintain sync with the 802.11 carrier. For the case that the AP may be co-located with the eNB, synchronization without frequent measurements may be maintained via the LTE carriers. When the WTRU comes out of DRX, it may also perform radio resource management (RRM) measurements as configured using LTE AS-SME. 
     The DRX and discontinuous transmission (DTX) parameters may be communicated by the LTE AS-SME to the 802.11 SME in the WTRU, which then schedules the appropriate listen interval with the AP via legacy power save mode. This may require the DRX Off duration to be an integer multiple of the beacon interval. Further, the QoS parameters may be communicated to the 802.11 QoS, which may be used it to create a traffic specification (TSPEC) with the AP by sending an add traffic stream (ADDTS) frame. This may allow the WTRU to create a scheduled PSMP stream with the AP. A PSMP frame may be sent by the AP according to the service period, (i.e., packetization period sought by the WTRU), and may be synchronized to the scheduled power save period being used. In effect this creates mini-schedules for the medium, 8 milliseconds at a time, which may include uplink and downlink transmission times for the WTRU. The transceiver may shut down for all other times. 
     The Scheduled-PSMP sequence may be appropriate for applications such as conversational voice and video which generate a fairly steady flow of frames. However, applications such as internet surfing and e-mail that produce bursty traffic and long periods of inactivity are better served by a two-level idle duration structure. 
     An example implicit method of transitioning between the two modes is described herein. At the time of initial TSPEC creation and flow admittance by the AP, a schedule of Service Periods (SPs) and Service Intervals (SIs) may be established for the traffic stream (TS). During these SPs, the AP may schedule PSMP sequences to communicate with all WTRUs that have overlapping SPs. The SPs are scheduled with appropriate intervening SI to satisfy the QoS requirements of the particular TS. The WTRU and AP may transition to a pre-configured long SI if a pre-configured number of consecutive Uplink Transmission Times (UTTs) and Downlink Transmission Times (DTTs) pass without any uplink or downlink frames for the WTRU. 
     The WTRU then wakes up after every long SI interval to check for any downlink frames at the AP or to transmit any waiting frames in its own buffer. The AP also buffers frames for the WTRU during the long SI interval. The presence of frames in the uplink or downlink buffers causes the AP and WTRU to transition to the (short) SI. It may be conceivable to maintain different sets of parameters, (number of empty UTTs and DTTs to transition to long SI, long SI duration), for different access categories (ACs). Finally, the SI and long SI durations may be assigned identical values as the short DRX and long DRX cycles of LTE for inter-RAT alignment of activity cycles.  FIG. 24  shows an example diagram  2400  for implicit transitioning between (short) SI  2405  and long SI  2410 , and their alignment with LTE short DRX  2415  and long DRX  2420 . 
     Described herein is a user plane WLAN abstraction layer entity. The user-plane WLAN Abstraction layer entity may perform the following functions: assist in translation of scheduling related information, (MCS, TXOP per AC, max packet size, grant periods and the like), from 802.11 RAT to LTE; translate between LTE formats and 802.11 formats such as QoS; provide and control first in first out (FIFO) data buffers for de-randomizing data flows; and execute LCP algorithm in case of split LCP. 
     Described herein is scheduling and grant management. The WLAN Abstraction Layer interfaces with the 802.11 MAC and provides information on how much data it may potentially transmit within a given time period to the LTE Upper MAC entity. The WLAN Abstraction Layer may operate in a persistent scheduling mode or a dynamic scheduling mode. In persistent scheduling mode, where semi-static schedule covering a longer duration than an LTE sub-frame may be used. This mode may be suitable for applications generating a steady flow of packets such as conversational voice and video. In dynamic scheduling mode, where scheduling per individual time-unit such as a LTE sub-frame may be followed. This mode may be suitable for applications that generate bursty traffic such as internet surfing and e-mail. 
     In the persistent scheduling mode, a traffic stream (TS) may be set up with the AP based on the QoS parameters of the access category via a TSPEC. Then the AP schedules periodic service periods (SPs) with appropriate parameters, (duration and periodicity), to satisfy the QoS requirements. The AP shall try to schedule downlink transmissions to a WTRU with which it has already established scheduled SPs within the same SP. Performing uplink and downlink transmissions meant for a particular WTRU in the same SP results in improved transmission efficiency. Additional frames in either direction may be scheduled dynamically. 
     A TS may be set up by the exchange of an Add Traffic Stream (ADDTS) request and an ADDTS response between an AP and WTRU. Both the ADDTS request and ADDTS response frames contain the TSPEC element that specifies the traffic characteristics and QoS requirements of the requested TS. The ADDTS response frame also may include a schedule element, which specifies the SP schedule information. If the AP does not have adequate resources to meet the requested QoS, the TS setup may be rejected, and this may be indicated in the ADDTS response frame. At a later time, the schedule for a SP may be changed by sending a schedule frame with revised parameters. 
     Uplink or downlink transmissions may also be scheduled dynamically by starting a controlled access phase (CAP) by the AP, in response to a non-empty downlink buffer or a BSR from the WTRU. The AP may gain access to the channel by waiting for a shorter duration than other contending stations after the end of any ongoing transmission. 
     Described herein is buffer management. The WLAN Abstraction layer user-plane entity may maintain a set of FIFO data buffers as a mechanism to flow control data between the LCP entity in the upper MAC and the 802.11 MAC entity. It may also be required to interface with the 802.11 flow control indications and use the available room in the data buffers as input to determine the next grant that may be reported to the Upper MAC. 
     The BSR reported on the LTE carriers may be either configured to account for data that may be buffered for IEEE 802.11 UL, account for data buffer for LTE UL, account for data that may be buffered for IEEE 802.11 UL less the anticipated data that will be transmitted in the next scheduled PSMP UL, account for the data in the LTE UL plus data present in the glue layer buffer UL, or account for the data in the LTE UL+ data present in the WLAN Abstraction Layer buffer UL. 
     UL transmissions in the PSMP sequence may carry QoS messages indicating additional data remains. The information may be translated into a B SR-like report to the LTE upper stack. 
     The buffer status report may be augmented to take into account a 802.11 secondary carrier. This is applicable in the case of Split LCP, where a group of logical channels are ear-marked to be transmitted on 802.11 RAT. Several logical channel groups (LCGs) may be assigned to be transmitted over 802.11 secondary carrier(s). In the case of Combined and hybrid LCP, existing BSR mechanisms from LTE Release 10 may suffice. 
     Described herein are user data transfer over cellular and WLAN RATs.  FIG. 25  provides an example flowchart  2500  of uplink user plane procedures for cellular-controller 802.11 RAT addition and cellular-controlled Inter AP transfer. The entities involved are a WTRU  2505 , a source AP  2510 , a eNB  2515 , a target AP  2520  and a Serving Gateway (S-GW)/packet data network gateway (P-GW)  2525 . Upon initial start-up, the WTRU  2505  attaches to the network (1). At a later time, the WTRU  2505  may associate with the source AP  2510  (2). The association procedure may be implemented as described herein above, where association may be done without cellular assistance, association may be done with cellular assistance, and association may be done with cellular assistance and with bypassed WLAN authentication. This may be followed by data segmentation using the examples described herein below, where three different logical channel prioritization (LCP) versions are described: combined LCP, split LCP and hybrid LCP. 
     A radio link control (RLC) entity/layer at the eNB  2515  may receive packet data units (PDUs) from the cellular and WLAN RATs, and may performs PDU reordering of out-of-sequence PDUs (4). Based on factors including, but not limited to, changing channel conditions and network load balancing, the eNB  2515  may decide to transfer the WTRU  2505  association from the current/source AP  2510  to another/target AP  2520  within the same ESS (5). Cellular-controlled inter-AP transfer may be performed, either with or without cellular layer assistance (6). Inter-AP transfer procedural details and various methods are described herein. 
     The user-plane, X2′-U, switch from the source AP  2510  to the target AP may follow one of two methods. In a first method, the X2′-U link to the source AP  2510  may be interrupted upon eNB  2515  determination of inter AP transfer initiation. The user-plane may be restored to the target AP  2520  after the source AP  2510  receives a disassociate frame from the WTRU as described herein below for inter AP transfer procedures. 
     To limit data interruption duration, the second method allows user-plane data to be delivered to the source AP  2510  right up to the point of disassociation, at which time the user-plane traffic may be re-directed to the target AP  2520 . In both methods, the RLC entity/layer retransmissions are expected to recover any lost data during the switch from the source AP  2510  to the target AP  2515 . 
     Described herein is an 802.11 inter AP transfer.  FIGS. 26A and 26B  are an example flowchart  2600  for performing an inter AP transfer with cellular assistance. The entities involved are a WTRU  2605 , a current AP  2610 , a target AP  2615  and an eNB  2620 . Initially, the WTRU  2605  is attached to the cellular network after energizing ( 2622 ). When the WTRU  2605  is within range of an 802.11 AP, for example current AP  2610 , the WTRU  2605  associates with the current AP  2610  via one of the three methods described herein above ( 2624  and  2626 ). The WTRU  2605  may then at a later time determine that it must transition to the target AP  2615  due to link quality deterioration with the current AP  2610  ( 2628 ). 
     The Fast BSS Transition (FT) procedure may allow quick transition from one AP to another by performing the pre-association steps while being attached to the current AP  2610  ( 2630 ). The FT procedure may include the four-way handshake for key distribution followed by antenna beamforming training if operating in a DMG BSS ( 2632 ). The WTRU  2605  may send a disassociate message or signal to the current AP  2610  ( 2634 ), which in turn informs the eNB  2620  of the disassociation ( 2636 ). A reassociation request may then be sent by the WTRI  2605  to the target AP  2615  ( 2638 ), which in turn may send a reassociation response to the WTRU  2605  ( 2640 ). The target AP  2615  may inform the eNB  2620  of WTRU association and new quality of service (QoS) resource allocation ( 2642 ). A successful secure session is established between the WTRU  2605  and the target AP  2615  ( 2644 ). 
       FIGS. 27A and 27B  show an example flowchart  2700  for fast Inter AP transition with cellular layer assistance. The entities involved are a WTRU  2705 , a current AP  2710 , a target AP  2715  and an eNB  2720 . In general, the AP to AP transfer messages are passed through the eNB  2720 . The FT messages from the WTRU  2705  are encapsulated in radio resource control (RRC) messages to the eNB  2720 , which are then forwarded to the target AP  2715  on a X2′ interface. 
     Initially, the WTRU  2705  is attached to the cellular network after energizing ( 2722 ). When the WTRU  2705  is within range of an 802.11 AP, for example current AP  2710 , the WTRU  2705  associates with the AP  2710  via one of the three methods described herein above ( 2724  and  2726 ). The WTRU  2705  may then at a later time determine that it must transition to the target AP  2715  due to link quality deterioration with the current AP  27610  ( 2728 ). 
     The Fast BSS Transition (FT) procedure may allow quick transition from one AP to another by performing the pre-association steps while being attached to the current AP  2710  ( 2730 ). As stated above, the FT messages from the WTRU  2705  are encapsulated in RRC messages to the eNB  2720 , which are then forwarded to the target AP  2715  on a X2′ interface. Similarly, messages from the target AP  2715  are first sent to the eNB  2720  before being sent to the WTRU  2705 . The FT procedure may include the four-way handshake for key distribution followed by antenna beamforming training if operating in a DMG BSS ( 2732 ). The WTRU  2705  may send a disassociate message or signal to the current AP  2710  ( 2734 ), which in turn informs the eNB  2720  of the disassociation ( 2736 ). A reassociation request may then be sent by the WTRU  2705  to the target AP  2715  ( 2738 ), which in turn may send a reassociation response to the WTRU  2705  ( 2740 ). In this instance, the reassociation request may go directly to the target AP  2715 , as the FT procedure followed by beamforming has already been executed. The target AP  2715  may inform the eNB  2720  of WTRU association and new quality of service (QoS) resource allocation ( 2742 ). A successful secure session is established between the WTRU  2705  and the target AP  2715  ( 2744 ). 
     Described herein is a method for AP to AP transfer with cellular assistance and optimized security procedures. In this instance, the reassociation and security key exchange steps are optimized due to prior establishment of secure links from an eNB to a current AP and from the eNB to a target AP. The secure link from the WTRU to the current AP through the eNB, (that follows from cellular authentication procedures), allows the WTRU-to-AP authentication procedure to be truncated or even eliminated. Also, the PDCP layer security provided by the cellular network obviates the need for 802.11 key exchange and security procedures. Two examples of the optimized procedure are described herein below. 
       FIGS. 28A and 28B  show an example flowchart  2800  for AP to AP transfer with cellular assistance and optimized security procedures. The entities involved are a WTRU  2805 , a current AP  2810 , a target AP  2815  and an eNB  2820 . As before, the WTRU  2805  is attached to the cellular network after energizing ( 2822 ). When the WTRU  2805  is within range of an 802.11 AP, for example current AP  2810 , the WTRU  2805  associates with the AP  2810  via one of the three methods described herein above ( 2824  and  2826 ). The WTRU may then determine that it needs to transition to a target AP  2815  by proximity indication ( 2828 ) or by measuring the quality of the periodically received beacon of measurement pilot frames from all APs within communication range ( 2830 ). Antenna beamforming training may be performed with the target AP  2815  if it may be part of a DMG BSS ( 2832 ). 
     An association request, which may include QoS Resource Request, may originate from the eNB  2820  to the target AP  2815  ( 2834 ). This may be possible because QoS parameters of the traffic streams sought to be transferred to the target AP  2815  are available with the eNB  2820 . The target AP  2815  may send an association response to the eNB  2820  ( 2836 ). The eNB  2820  may then inform the WTRU  2805  of successful reassociation with the target AP  2815  ( 2840 ) and then facilitate the truncated authentication procedure described herein above ( 2842 ). The eNB  2820  may send a disassociate message to the current AP  2810  ( 2844 ). A successful secure session is established between the WTRU  2805  and the target AP  2815  ( 2846 ). 
     Described herein is an example method of cellular assisted AP to AP transfer with optimized security procedures without WLAN authentication. This may be similar to the cellular-assisted, optimized AP to AP transfer procedure described herein with respect to  FIG. 28 . However, similar to the initial association procedure without authentication described herein, the authentication steps are skipped due to pre-authentication of the WTRU, current AP and target AP to the eNB and prior establishment of secure links from the eNB to the WTRU, current AP and target AP. Security key exchange may also be skipped due to PDCP-level encryption already in use at the cellular layer. 
       FIG. 29  shows an example flowchart  2900  of cellular assisted AP to AP transfer with optimized security procedures without WLAN authentication. The entities involved are a WTRU  2905 , a current AP  2910 , a target AP  2915  and an eNB  2920 . As before, the WTRU  2905  is attached to the cellular network after energizing ( 2822 ). When the WTRU  2905  is within range of an 802.11 AP, for example current AP  2910 , the WTRU  2905  associates with the AP  2910  via one of the three methods described herein above ( 2924  and  2926 ). The WTRU may then determine that it needs to transition to a target AP  2915  by proximity indication ( 2928 ) or by measuring the quality of the periodically received beacon of measurement pilot frames from all APs within communication range ( 2930 ). Antenna beamforming training may be performed with the target AP  2915  if it may be part of a DMG BSS ( 2932 ). 
     An association request, which may include QoS Resource Request, may originate from the eNB  2920  to the target AP  2915  ( 2934 ). This may be possible because QoS parameters of the traffic streams sought to be transferred to the target AP  2915  are available with the eNB  2920 . The target AP  2915  may send an association response to the eNB  2920  ( 2936 ). The eNB  2920  may then inform the WTRU  2905  of successful reassociation with the target AP  2915  ( 2938 ). The eNB  2920  may send a disassociate message to the current AP  2910  ( 2940 ). A successful secure session is established between the WTRU  2905  and the target AP  2915  ( 2942 ). 
     Several types of Logical channel prioritization (LCP) are proposed below. Depending on the deployment and application scenarios, any of the LCP types may be used. Any LCP type mentioned below may be used with either MAC level aggregation or below the MAC aggregation. 
     Combined LCP may be performed across all logical channels at an LTE TTI interval rate. This type of LCP algorithm ensures that data is prioritized irrespective of which underlying RAT the data is carried on. At each LTE TTI, a combined LCP algorithm may be invoked. Grants for each of the LTE component carriers may be available at this point. Depending on the IEEE 802.11 protocol used, a different set of grant related information may be fed by an IEEE 802.11 RAT. 
     When a distributed coordinated function (DCF) is used, there may be no grant guarantees in IEEE 802.11 In such a case, an IEEE 802.11 RAT may provide the maximum data packet it can send based on its current CSI feedback, its data rate capabilities, and the like, to the combined LCP algorithm as input. When using an IEEE 802.11e amendment, an IEEE 802.11 RAT may provide the maximum data packet it can send for each access category based on TXOP limit, its current CSI feedback, and its data rate capabilities and the like to the combined LCP algorithm as an input. In this case, an IEEE 802.11 RAT may be providing a maximum data packet it can send for each of the four access categories specified by IEEE 802.11e. The RRC may provide additional information to a MAC layer on how to map different access categories to logical channel priorities. 
     When a dedicated grant is possible as part of an IEEE 802.11 protocol used, (for example IEEE 802.11ad), an IEEE 802.11 RAT may provide the grant information and maximum data packet it can send based on its current CSI feedback, its data rate capabilities, and the like, to a combined LCP algorithm as input. 
     Most IEEE 802.11 protocols are not time slotted and are not TTI aligned to an LTE air-interface. Since the combined LCP algorithm may be executed at an LTE TTI rate, these aspects have to be accounted for in the glue layer. As can be seen from the illustration  3000  in  FIG. 30 , a combined LCP algorithm may be executed every LTE TTI  3005 , and an IEEE 802.11 RAT may provide feedback with regard to its capability to transmit in that TTI. Also an IEEE 802.11 RAT may not be able to gain access to the channel every LTE TTI, but may get access at different points shown as A, B and C. 
     There may be some aspects that are inherently different for IEEE 802.11 protocols that have to be taken into account for a combined LCP algorithm. Once a certain amount of data is provided to an IEEE 802.11 RAT to be transmitted, either due to contention or channel conditions or retransmissions, the IEEE 802.11 RAT may not be able to deliver this data as compared to an LTE air-interface, where a grant guarantees a TXOP. Due to the above mentioned reasons, if the internal buffers provided by the IEEE 802.11 RAT are deemed full based on a threshold, the IEEE 802.11 RAT may project the maximum data rate it can transmit in a given LTE TTI to be potentially less, (including zero bits), than what it may actually transmit in that time interval. 
     This LCP method may also lead to out of sequence packets at the radio link control (RLC) layer or entity. For baseline LTE Release 8 (R8)/10 (R10) RLC-acknowledge mode (AM), this is not an issue as it is capable of handling out-of-sequence packet data units (PDUs). If RLC re-segmentation is used, care must be taken in how the timer t-Reordering value is set as different segments might take different paths, (via cellular or 802.11 links). Baseline LTE R8/R10 RLC-unacknowledged mode (UM) may also be capable of handling out-of-sequence UM PDUs. This is handled again by using timer t-Reordering. The timer t-Reordering may be configured per RLC entity. 
     In split LCP, logical channels may either be mapped to LTE or IEEE 802.11 RAT, but not to both at the same time. Thus, certain traffic, (identified by specific logical channels), may be mapped to be carried over an IEEE 802.11 RAT at a configuration time. This mapping may not change on a TTI basis, but may be allowed to be updated on a much coarser scale, (for example using RRC (re)configuration messaging). 
     An LTE MAC may perform LCP similar to a baseline, for the logical channels that are mapped to LTE. An IEEE 802.11 RAT may perform LCP based on the logical channels that are mapped to IEEE 802.11 This LCP for IEEE 802.11 may be executed in the glue layer using data from each logical channel, such as buffer occupancy, SDU sizes and the like, and logical channel priority information provided during configuration along with MCS, TXOP and grant period information from an IEEE 802.11 stack. 
     In hybrid LCP, an LTE stack may first execute its LCP to satisfy prioritized bit rate (PBR) requirements for all logical channels in that TTI and also maximum bit rate (MBR) requirements for some channels to the extent that the LTE grant allows it. The remaining MBR data for each of the remaining logical channels may be provided to an IEEE 802.11 RAT for transmission. The IEEE 802.11 RAT may perform LCP for the MBR data for the logical channels it is provided with in that time interval. Hybrid LCP may lead to out-of-order packet arrival at the receiver, and since RLC supports out-of-order reception, this may not be an issue. 
     Described herein are radio resource management for 802.11 CA with 3GPP RAN. In order for the network to understand the load for different APs and channels within a particular AP, the network may use existing measurements as defined in IEEE 802.11 protocols or configured as described herein above. 
     The LTE AS-SME may configure measurements in the WTRU and obtain measurement reports as needed. If an LTE node and AP are integrated, (either co-located or non-co-located), the LTE node may request its AP to perform measurements related to BSS transition capability. Using a BSS transition management query, BSS transition management request, or BSS transition management response frames, the AP may be able to query the WTRU of neighboring APs and how the WTRU ranks the neighboring APs. 
     The AP may provide this information to a network management entity in an LTE node, which may use it for load balancing purposes. This mechanism may also take the WTRU&#39;s view and which APs it prefers. Based on this information and other RRM inputs, the LTE node may request the WTRU to disassociate with the AP that it is currently associated with to move to a different AP. 
     The network management entity may also request the AP to configure measurements at the WTRU to understand the channel load by configuring channel load measurement reports. These measurements may be measured using either physical or virtual carrier sense mechanisms at the WTRU. The WTRU may report these as a percentage of channel busy time over a measured period. The network may also use this information for load balancing purposes. 
     As an alternative technique, an AP may signal to another AP a request for a channel load report, assuming an AP supports performing channel load measurements. Since an AP may be a superset of a WTRU, it may support the measurement of the capabilities of a WTRU if these are implemented in the AP. 
     In order to monitor an IEEE 802.11 link, an IEEE 802.11 link layer feedback mechanism may be used to report to the RRC layer whether the link is up or down via the glue layer or WLAN abstraction layer. As part of the WLAN abstraction layer, a UL and DL data buffer may be set up to de-randomize the data flow through the glue layer. In the DL, data from LTE higher layers, (i.e., transport blocks), may be deposited in the buffer, and glue layer buffer status (GBS) may be visible to the LTE MAC. A GBS may also be available for the UL so that the LTE MAC knows when UL data is available to be fetched. If the DL GBS for a WTRU is not reduced by the IEEE 802.11 MAC for a specified period, and UL data does not arrive in the IEEE 802.11 carrier, a link failure may be deduced by LTE and the data in the DL glue layer buffer may be ‘canceled’ from the IEEE 802.11 flow and redirected to a LTE carrier. 
     Multiple methods may be available to explicitly test the link. Such tests may be configured in the IEEE 802.11 carrier, via the WLAN abstraction layer, by LTE. The results of such tests may be sent to the LTE layer for additional processing and determination of the availability of the link for that WTRU. Such methods may include a probe request/response, Request to Send and Clear to Send (RTS/CTS) exchanges, and an MCS request/response. IEEE 802.11 may also know that the link is up due to recent unsolicited feedback from the WTRU. For example, if the WTRU sends an unsolicited MCS feedback in the last M mSec, then the link may be considered to be functioning. The IEEE 802.11 may also have a missing positive acknowledgement (ACK)/negative acknowledgement (NACK), (or other response missing responses), that may indicate that the link is lost or of low quality and send that information, (via the WLAN abstraction layer) to the LTE stack. Any of these mechanisms may be used to report to the RRC/LTE AS-SME layer of link failure. 
     In some deployments, the IEEE 802.11 AP may not be co-located with the LTE eNB, and may appear as a downlink only channel, such that the feedback (MAC ACK/NACKs, CQI, measurements) from the IEEE 802.11 channel are fed back to the LTE eNB. This may require an additional translation entity in the WTRU that encapsulates and sends the IEEE 802.11 feedback from an IEEE 802.11 MAC at the receiving end to the LTE uplink channel. 
     The power amplifier (PA) configuration for a WTRU may be signaled to an LTE system, (e.g., as part of capability class information). In the event that a single PA is used to support both an IEEE 802.11 carrier and an LTE carrier, the maximum transmit (Tx) power for the capability class may need to consider the sum of the Tx powers in both carriers. 
     In an example, if an IEEE 802.11 transmission has started before an LTE UL grant is determined by the WTRU and the transmission may still exist at the time the LTE transmission starts, the Tx power of the IEEE 802.11 transmission may not be reduced when the LTE transmission starts. The power of the LTE transmission with any backoff may be computed as usual except that the maximum Tx power in the UL power control (PC) algorithm may be reduced by the amount of the power used in the IEEE 802.11 transmission. 
     In another example, if an LTE transmission has started before a scheduled IEEE 802.11 UL is detected and the transmission will still exist at the time that IEEE 802.11 transmission starts, the Tx power of the LTE transmission may not be reduced when the IEEE 802.11 transmission starts. Alternatively, the power of the IEEE 802.11 transmission may be unchanged as long as the increased total power is below the Pmax of the PA. Otherwise, the IEEE 802.11 transmission may be reduced to the available power or aborted. LTE may facilitate this by controlling an attenuator in the feed of the PA. 
     If an LTE transmission has started and there is insufficient headroom for any unscheduled IEEE 802.11 transmission, the IEEE 802.11 transmission may be reduced to the available power or aborted. LTE may facilitate this by controlling an attenuator in the feed of the PA. Alternatively, a NAV counter may be incremented at the beginning of the LTE transmission by an amount sufficient to ensure no IEEE 802.11 unscheduled transmissions are possible. 
     Although features and elements are described above in particular combinations, one of ordinary skill in the art will appreciate that each feature or element may 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.