Abstract:
A method and apparatus of offloading traffic in a wireless communication system is disclosed. The wireless communication system, for example, an evolved Node-B (eNB) comprises a transmitter, a receiver, and a processor. The transmitter is configured to transmit, to a wireless transmit/receive unit (WTRU), a broadcast system information (SI) message of a Long Term Evolution (LTE) system indicating that traffic off-load (TO) is supported. The transmitter is further configured to, after transmitting the broadcast SI message, transmit a non-access stratum (NAS) message to the WTRU, wherein the NAS message indicates that a TO service is available for the WTRU. The receiver is configured to receive, from the WTRU, a signaling for initiating TO service in response to at least the transmitted NAS message. The processor, operatively coupled to the transmitter and the receiver, is configured to communicate using the TO service while maintaining at least one bearer with the WTRU.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of U.S. patent application Ser. No. 12/987,644, filed on Jan. 10, 2011, which claims the benefit of U.S. Provisional Patent Application No. 61/293,423 filed on Jan. 8, 2010, and U.S. Provisional Patent Application No. 61/304,199 filed on Feb. 12, 2010, the contents of which are hereby incorporated by reference herein. 
     
    
     BACKGROUND 
       [0002]    Selected internet protocol (IP) traffic offload (SIPTO) is a method to offload traffic from a wireless communication system operator&#39;s core network to a defined IP network that is close to a point of attachment to the access point of a wireless transmit receive unit (WTRU). When reference is made to a core network with respect to the data plane, the nodes under consideration include the serving gateway (SGW) and the packet data network gateway (PDW) in, for example, a long term evolution (LTE) compliant system, or the serving general packet radio service (GPRS) support node (SGSN) and gateway GPRS support node (GGSN) in a universal mobile telephone system (UMTS) terrestrial radio access network (UTRAN), although the disclosure herein is not limited to any one network architecture or technology. The goal of SIPTO is to offload some of the IP traffic from traversing these nodes. 
         [0003]    SIPTO may require that a WTRU may process both offloaded traffic and non-offloaded, or non-SIPTO, traffic that goes through the operators network. SIPTO may be used in, for example, a UTRAN, an evolved UTRAN (E-UTRAN) and a macro cell with a home eNodeB (HeNB), for example. 
       SUMMARY 
       [0004]    A method and apparatus of performing selective internet protocol (IP) offload (SIPTO) or local IP access (LIPA) is disclosed. A wireless transmit receive unit (WTRU) receives a broadcast message from a Node-B. Then the WTRU receives a message from the Node-B that SIPTO service, or LIPA service is available for that WTRU. The WTRU then communicates using the SIPTO or LIPA service. 
         [0005]    A method an apparatus for receiving a paging message for SIPTO or LIPA services is also disclosed. The paging message includes an indicator that indicates that the message is for SIPTO or LIPA communications. The indicator may be a temporary mobile subscriber identity (TMSI) assigned by the network specifically for SITPO or LIPA communications. The indicator may also be a single bit designated to indicate that a paging message is a for SIPTO or LIPA traffic. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    A more detailed understanding may be had from the following description, given by way of example in conjunction with the accompanying drawings wherein: 
           [0007]      FIG. 1A  is a system diagram of an example communications system in which one or more disclosed embodiments may be implemented; 
           [0008]      FIG. 1B  is a system diagram of an example wireless transmit/receive unit (WTRU) that may be used within the communications system illustrated in  FIG. 1A ; 
           [0009]      FIG. 1C  is a system diagram of an example radio access network and an example core network that may be used within the communications system illustrated in  FIG. 1A ; 
           [0010]      FIG. 2  is an example architecture of a wireless network configured to perform SIPTO; 
           [0011]      FIG. 3  is an example flow diagram of procedure for indicating support of SIPTO services; 
           [0012]      FIG. 4  is an example flow diagram of a procedure for triggering delivery of SIPTO service; 
           [0013]      FIG. 5  is an example flow diagram of a procedure for stopping delivery of SIPTO services; and 
           [0014]      FIG. 6  is an example flow diagram of a paging procedure using SIPTO. 
       
    
    
     DETAILED DESCRIPTION 
       [0015]      FIG. 1A  is a diagram of an example communications system  100  in which one or more disclosed embodiments may be implemented. The communications system  100  may be a multiple access system that provides content, such as voice, data, video, messaging, broadcast, etc., to multiple wireless users. The communications system  100  may enable multiple wireless users to access such content through the sharing of system resources, including wireless bandwidth. For example, the communications systems  100  may employ one or more channel access methods, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single-carrier FDMA (SC-FDMA), and the like. 
         [0016]    As shown in  FIG. 1A , the communications system  100  may include wireless transmit/receive units (WTRUs)  102   a,    102   b,    102   c,    102   d,  a radio access network (RAN)  104 , a core network  106 , a public switched telephone network (PSTN)  108 , the Internet  110 , and other networks  112 , though it will be appreciated that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and/or network elements. Each of the WTRUs  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 netbook, a personal computer, a wireless sensor, consumer electronics, and the like. 
         [0017]    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 core network  106 , the Internet  110 , and/or the networks  112 . By way of example, the base stations  114   a,    114   b  may be a base transceiver station (BTS), a Node-B, a Home Node B, a Home, 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. 
         [0018]    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, etc. 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. 
         [0019]    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, etc.). The air interface  116  may be established using any suitable radio access technology (RAT). 
         [0020]    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 Packet Access (HSDPA) and/or High-Speed Uplink Packet Access (HSUPA). 
         [0021]    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 UMTS Terrestrial Radio Access (E-UTRA), which may establish the air interface  116  using Long Term Evolution (LTE) and/or LTE-Advanced (LTE-A). 
         [0022]    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 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), GSM EDGE (GERAN), and the like. 
         [0023]    The base station  114   b  in  FIG. 1A  may be a wireless router, Home Node B, Home , or access point, for example, and may utilize any suitable RAT for facilitating wireless connectivity in a localized area, such as a place of business, a home, a vehicle, a campus, and the like. In one embodiment, the base station  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, etc.) 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 core network  106 . 
         [0024]    The RAN  104  may be in communication with the core network  106 , which may be any type of network configured to provide voice, data, applications, and/or voice over internet protocol (VoIP) services to one or more of the WTRUs  102   a,    102   b,    102   c ,  102   d.  For example, the core network  106  may provide call control, billing services, mobile location-based services, pre-paid calling, Internet connectivity, video distribution, etc., and/or perform high-level security functions, such as user authentication. Although not shown in  FIG. 1A , it will be appreciated that the RAN  104  and/or the core network  106  may be in direct or indirect communication with other RANs that employ the same RAT as the RAN  104  or a different RAT. For example, in addition to being connected to the RAN  104 , which may be utilizing an E-UTRA radio technology, the core network  106  may also be in communication with another RAN (not shown) employing a GSM radio technology. 
         [0025]    The core network  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 internet protocol suite. The networks  112  may include wired or wireless communications networks owned and/or operated by other service providers. For example, the networks  112  may include another core network connected to one or more RANs, which may employ the same RAT as the RAN  104  or a different RAT. 
         [0026]    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. 
         [0027]      FIG. 1B  is a system diagram of an example WTRU  102 . As shown in  FIG. 1B , the WTRU  102  may include a processor  118 , a transceiver  120 , a transmit/receive element  122 , a speaker/microphone  124 , a keypad  126 , a display/touchpad  128 , non-removable memory  106 , removable memory  132 , a power source  134 , a global positioning system (GPS) chipset  136 , and other peripherals  138 . It will be appreciated that the WTRU  102  may include any sub-combination of the foregoing elements while remaining consistent with an embodiment. 
         [0028]    The processor  118  may be a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), a plurality of microprocessors, one or more microprocessors in association with a DSP core, a controller, a microcontroller, Application Specific Integrated Circuits (ASICs), Field Programmable Gate Array (FPGAs) circuits, any other type of integrated circuit (IC), a state machine, and the like. The processor  118  may perform signal coding, data processing, power control, input/output processing, and/or any other functionality that enables the WTRU  102  to operate in a wireless environment. The processor  118  may be coupled to the transceiver  120 , which may be coupled to the transmit/receive element  122 . While  FIG. 1B  depicts the processor  118  and the transceiver  120  as separate components, it will be appreciated that the processor  118  and the transceiver  120  may be integrated together in an electronic package or chip. 
         [0029]    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. It will be appreciated that the transmit/receive element  122  may be configured to transmit and/or receive any combination of wireless signals. 
         [0030]    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 . 
         [0031]    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. 
         [0032]    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  106  and/or the removable memory  132 . The non-removable memory  106  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). 
         [0033]    The processor  118  may receive power from the power source  134 , and may be configured to distribute and/or control the power to the other components in the WTRU  102 . The power source  134  may be any suitable device for powering the WTRU  102 . For example, the power source  134  may include one or more dry cell batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, and the like. 
         [0034]    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. It will be appreciated that the WTRU  102  may acquire location information by way of any suitable location-determination method while remaining consistent with an embodiment. 
         [0035]    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. 
         [0036]      FIG. 1C  is a system diagram of the RAN  104  and the core network  106  according to an embodiment. As noted above, the RAN  104  may employ an E-UTRA radio technology to communicate with the WTRUs  102   a,    102   b,    102   c  over the air interface  116 . The RAN  104  may also be in communication with the core network  106 . 
         [0037]    The RAN  104  may include eNode-Bs  140   a,    140   b,    140   c,  though it will be appreciated that the RAN  104  may include any number of eNode-Bs while remaining consistent with an embodiment. The eNode-Bs  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 eNode-Bs  140   a,    140   b,    140   c  may implement MIMO technology. Thus, the eNode-B  140   a,  for example, may use multiple antennas to transmit wireless signals to, and receive wireless signals from, the WTRU  102   a.    
         [0038]    Each of the eNode-Bs  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 uplink and/or downlink, and the like. As shown in  FIG. 1C , the eNode-Bs  140   a,    140   b,    140   c  may communicate with one another over an X2 interface. 
         [0039]    The core network  106  shown in  FIG. 1C  may include a mobility management gateway (MME)  142 , a serving gateway  144 , and a packet data network (PDN) gateway  146 . While each of the foregoing elements are depicted as part of the core network  106 , it will be appreciated that any one of these elements may be owned and/or operated by an entity other than the core network operator. 
         [0040]    The MME  142  may be connected to each of the eNode-Bs  142   a,    142   b,    142   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. 
         [0041]    The serving gateway  144  may be connected to each of the s  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- handovers, triggering paging when downlink 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. 
         [0042]    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. 
         [0043]    The core network  106  may facilitate communications with other networks. For example, the core network  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 core network  106  may include, or may communicate with, an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that serves as an interface between the core network  106  and the PSTN  108 . In addition, the core network  106  may provide the WTRUs  102   a,    102   b,    102   c  with access to the networks  112 , which may include other wired or wireless networks that are owned and/or operated by other service providers. 
         [0044]      FIG. 2  shows an example LTE system  200  configured to provide SIPTO services. The system includes a WTRU  210  in communication with an eNB  220  that is located in a radio access network (RAN)  225 . The eNB  220  is also in communication with S-GW  230 , which is also in communication with L-PGW  235  and a core network (CN)  240 . The CN  240  includes an MME  245  and a P-GW  250 . 
         [0045]    The WTRU  210  communicates with the eNB  220  over a wireless air interface  255 . The eNB  220  also communicates with the S-GW  230  over an S1-U interface  260 . The S-GW  230  communicates with the L-PGW  235  over an S 5  interface  265 , and with the P-GW  250  over an S5 interface  270 . The S-GW  230  also communicates with the MME  245  over an S11 interface  275 . Two traffic streams are also shown, a SIPTO traffic stream  280  that is routed through the S-GW  230  to the L-PGW  265 , and a CN traffic stream  285  that is routed through the S-GW  230  to the P-GW  250  in the CN  240 . 
         [0046]    The eNB  220  may also be a HeNB configured to perform SIPTO in a home network of the user of the WTRU  210 . In that case, traffic may be offloaded locally to a user&#39;s home network. The home network may be an IP network that is connected to other devices such as a printer, a television, and a personal computer, for example. These nodes on the home network may be using private addressing. 
         [0047]    Also the system  200  may be configured to provide Local IP Access (LIPA). While many of the features disclosed herein are described with regard to SIPTO, they may also be applied to LIPA and SIPTO systems for HeNBs. For example, SIPTO or LIPA may include single or multiple packet data network (PDN) connections, deployment behind network address translation (NAT), and the like. 
         [0048]    Furthermore, for traffic going through the mobile operator&#39;s core network, the S-GW  230  user plane functions may be located within the CN  240 . Also, mobility management signalling between a WTRU  210  and the network may be handled in the CN  240 . Session management signalling, such as bearer setup, for LIPA or SIPTO traffic, and traffic going through the CN  240  may terminate in the CN  240 . Also, reselection of a WTRU&#39;s offload point for SIPTO traffic that is geographically or topologically close to the WTRU  210  may be possible during idle mode mobility procedures. 
         [0049]    The SIPTO system may include a local gateway that is close to a WTRU&#39;s point of attachment to the access network. The local gateway may perform IP traffic offload based on some policy or configuration, for example, based on the IP address destination. IP traffic may go through the local gateway rather than through the operator&#39;s core network via, for example, an S-GW and a P-GW or via an SGSN and a GGSN (not pictured). 
         [0050]    Depending on the network technology, a local break point or local gateway may be in the HeNB subsystem or in a radio network controller (RNC). Also, the SGSN may be responsible for both control and user plane in some networks, while the user and control planes are taken care of by a mobility management entity (MME) and an SGW in others. 
         [0051]    A local gateway, such as the L-PGW  235 , may have certain functionalities of a PDW/GGSN. For example, the local gateway may have the following functionalities IP address allocation, direct tunneling with the RAN  225  in connected mode, per WTRU policy based packet filtering, of rate policing/shaping. In order to perform SIPTO transfers to a network, such as a local network or Intranet, for example, a proper PDN connection may be required. A WTRU may set an access point name (APN) to a specific value when requesting a PDN connection or when requesting the establishment of a packet data protocol (PDP) context. 
         [0052]      FIG. 3  is a flow diagram showing an example trigger procedure  300  for the WTRU to communicate using SIPTO or LIPA services. First, the eNode B broadcasts an indication of support of SIPTO or LIPA to indicate that such a service is available in a network for some WTRUs, at  310 . The eNode B may then send a NAS message to a WTRU indicating that SIPTO or LIPA service is allowed for that WTRU, at  320 . The WTRU may then communicate using the SIPTO or LIPA service, at  330 . 
         [0053]    It should be noted that the service indication of support for SIPTO or LIPA service may be broadcasted on a per cell basis, or for another area such as a routing area or tracking area. The indication may be broadcast in a system information message, for example. Further, the cell may be a CSG cell in the case of LIPA. The cell may also provide an indication of the availability of SIPTO or LIPA services in a NAS message such as an Attach Accept, TAU Accept, or RAU Accept for example. 
         [0054]    The WTRU may also provide an indication of SIPTO or LIPA capability to the network. This may be useful whether the WTRU supports SIPTO or LIPA for macro cells, for HeNBs, or both. A WTRU and/or the network may also provide an indication of support for SIPTO or LIPA in an LTE system only, UTRAN only, or both, or also any other combination of systems including non-3GPP access. 
         [0055]    The availability of SIPTO or LIPA service, the level of support, the type of system, and the like may also be provided to the WTRU using an access network discovery and selection function (ANDSF). This may be provided as a policy that helps the WTRU change or use certain access technologies. 
         [0056]    The indicators described herein may be used relative to a target system or cell. For example, when the WTRU is performing inter-system change or packet switched (PS) handover from one network to another, such as from LTE to UTRAN, the indication of SIPTO or LIPA support in the target system may be included in a mobility message such as the MobilityFromEUTRACommand. The indication may also be transmitted upon release of a radio resource control (RRC) connection with redirection information. The WTRU may use the indication to trigger a PDP context activation to a certain GGSN or PDN connection to a specific PDW for inter-system change from UTRAN to E-UTRAN, for example. The WTRU may also be provided with a default access point name (APN) or it may derive the APN based on its location. Alternatively, the APN may be left undetermined or set to a random or unknown value. The network may choose the appropriate gateway based on some policies. Indicators may also be used in an intra-system handover. The indications may be forwarded to the upper layers, such as the NAS, in order to initiate any signaling that is needed for SIPTO or LIPA services. 
         [0057]    An indication about the support of SIPTO or LIPA for CSG cells may be used. The WTRU may maintain the indication for all or some of its CSG IDs in, for example, a white list, maintained by the access stratum, or a radio resource control (RRC) entity. Alternatively, the WTRU may maintain the indication for all or some of its CSG IDs in the USIM, the allowed operator list maintained by the Non access stratum (NAS), or the operator controlled list maintained by NAS. 
         [0058]    The WTRU may be informed if the local gateway that serves the WTRU for SIPTO or LIPA is standalone or collocated with a CSG cell. The WTRU may deactivate its PDN connection(s) either locally or by signaling the network (MME  245  or SGSN) when the WTRU leaves its previous cell where SIPTO or LIPA was provided. Moreover, the deactivation may avoid paging the WTRU for SIPTO or LIPA traffic when the WTRU is in idle mode. 
         [0059]      FIG. 4  shows an example procedure  400  for triggering delivery of SIPTO service. The procedure begins when the WTRU enters a specific area, such as routing area (RA), tracking area (TA) or Local Area (LA) or camps on a CSG cell, at  410 . Then the WTRU or network initiates the signaling for SIPTO, or the WTRU starts receiving SIPTO service, at  420 . 
         [0060]    The initiation of SIPTO or LIPA service occurs when the offload of traffic occurs. The WTRU may be unaware of the offload process. SIPTO or LIPA initiation may also occur when the signaling that might be needed in order to offload selected traffic occurs, for example, when a new PDN connection is needed. 
         [0061]    The WTRU may trigger SIPTO or LIPA services when the WTRU enters a specific tracking area identity (TAI) or routing area identity (RAI), or a specific service area. Alternatively, the WTRU may use an indication it receives in a TAU Accept or a RAU Accept message in order to take specific action, such as the establishment of a new PDN connection or activation of a new PDP context, for example. 
         [0062]    A trigger may occur when the WTRU camps on, or goes to, a CSG cell. The WTRU may trigger a PDN connection even if it is unaware of whether SIPTO or LIPA is supported on a CSG cell. Otherwise, the WTRU may use the indications as set forth herein, for each CSG identity, to determine triggering of any necessary signaling for SIPTO, such as establishment of a new PDN connection or PDP context activation, for example. Alternatively, this may be done upon manual selection of CSG or macro cells. 
         [0063]    A trigger may occur when a WTRU receives indications from the network that SIPTO or LIPA service is available using, for example, dedicated signaling such as an EPS mobility management (EMM) information message or other NAS or radio resource control (RRC) messages. 
         [0064]    If the establishment of a new PDN connection, activation of a new PDP context or modification of any bearer/context is required for SIPTO or LIPA, the network may also initiate the procedures. For example, a PDN connection may be initiated by a WTRU. The network may initiate a PDN connection towards the WTRU when the network decides to deliver SIPTO or LIPA services to the WTRU. This may be achieved using a session management message. Alternatively, the network may directly send a message, such as an Activate Default EPS Bearer Context to the WTRU. A similar message may be sent in a UTRAN for PDP context activation. The network may include the APN of the gateway that is performing traffic offload for the WTRU. Moreover, the network may add an EPS session management (ESM) cause to indicate that the connection is for SIPTO or LIPA service. 
         [0065]    The WTRU may use any of the indicators disclosed herein to display to the user of the WTRU any relevant information that is related to SIPTO or LIPA. The user may use the information for many purposes, such as starting specific services, local file transfer, and the like. 
         [0066]    The WTRU may provide preferences regarding traffic, such as preferences as to which traffic should be offloaded. Other triggers may be related to quality of service (QoS). Any degradation in received QoS may trigger the start of a SIPTO procedure so that traffic is diverted away from the CN. 
         [0067]    At each connection establishment, the RAN may provide at least one IP address to the network nodes. The network nodes may then choose a local gateway for SIPTO or LIPA. However, at the point of connection establishment, the RAN may not know what data type, that is, SIPTO or non-SIPTO, will be sent by the WTRU . Several gateways may be made ready as potential paths or routes for SIPTO or LIPA traffic. Alternatively, a HeNB gateway (GW) may receive at least the first user plane packet before it may suggest a routing path or a local gateway for SIPTO or LIPA. Alternatively, the choice of path or gateway may be made for each bearer context or PDP context. An HeNB GW, or any other node that needs to take an action for SIPTO or LIPA service provision, such as the RAN, may decide whether packets should not go through the core network based on mappings to certain bearer or contexts which are known to be SIPTO or LIPA affected. Specific bearers may be known to carry SIPTO or LIPA traffic or non-SIPTO traffic. 
         [0068]    The same triggers defined in relation to starting SIPTO or LIPA service may also be used to stop the delivery of SIPTO or LIPA services. The network may stop the offload of selected traffic, possibly without the WTRU being aware of the stopping of the service. The network may also stop the exchange of signaling between the WTRU and the network, such as a request to disconnect from a PDN or to deactivate a PDP context. The signaling may be triggered by either the network or the WTRU. In addition, the WTRU and network may initiate an end to SITPO or LIPA service delivery based on an expiration of a timer. For example, when no user data is exchanged for a specific configurable or default time, the timer may expire and SIPTO or LIPA service may be closed. 
         [0069]      FIG. 5  shows an example procedure  500  for the WTRU to stop LIPA services if the WTRU&#39;s subscription on a CSG expires. The WTRU is connected to a CSG and communicates using LIPA services, at  510 . The WTRU is handed over from a CSG from which LIPA service was provided, to a target cell on which LIPA service is not provided, at  520 . Then, the WTRU may deactivate any PDN connection locally without signaling to the MME, at  530 . Alternatively, the deactivated bearers may be signaled in other messages, such as TAU or RAU requests and responses, for example. 
         [0070]    The WTRU or a user of the WTRU may provide preferences about what traffic should not be offloaded. Other triggers are possible and may be related to QoS. For example, any degradation in received QoS may cause a stop of SIPTO or LIPA and traffic may be diverted via the core network. 
         [0071]      FIG. 6  shows an example procedure  600  for performing paging in a SIPTO enabled system. The procedure starts when the WTRU receives a paging message including an indication that the paging message is for SIPTO and a CSG ID, at  610 . Then the WTRU responds to the paging for SIPTO service message, at  620 . Then the network establishes resources for SITPO bearers and the WTRU maintains non-SIPTO bearers, at  630 . 
         [0072]    The network may indicate to the WTRU that a paging message, sent via RRC signaling, is due to SIPTO or LIPA traffic. A specific SIPTO or LIPA identifier (ID) may be used for the page to differentiate the SIPTO or LIPA page from other pages. The ID may be similar to a temporary mobile subscriber identity (TMSI) such as an S-TMSI or a P-TMSI, and may be assigned by the network when the SIPTO or LIPA service is initiated. The network may allocate this ID in a message, such as an NAS message. The NAS message may be, for example, an Attach Accept, TAU Accept, RAU Accept, and the like. Additionally, a new core network domain identifier in the RRC paging message may be used to indicate that the paging is for SIPTO or LIPA. Also, a bit may be used to indicate that a paging message is for SIPTO or LIPA traffic. 
         [0073]    The WTRU may respond to the paging for SIPTO or LIPA by sending a message, such as the NAS Service Request message, for example, or another message for similar purposes. An establishment cause may be used when a WTRU is requesting an RRC connection or NAS signaling connection for SIPTO or LIPA traffic. 
         [0074]    If the WTRU requests an RRC connection, a NAS signaling connection, or a mobile originating or terminating SIPTO or LIPA traffic and sends a message, such as a Service Request message or other message with a similar purpose, the radio and S1 bearers may not be established for enhanced packet service (EPS) bearer contexts that are used for traffic that goes through the CN. In addition, the WTRU may not deactivate the EPS bearer contexts for which no radio or S1 bearers were established, and maintains the existing non-SIPTO bearers. The WTRU and the network may use other signaling, such as an RRC message (RRCConnectionReconfiguration) for example, to establish radio and S1 bearers for CN traffic when it is available. The WTRU may also trigger establishment of radio and S1 bearers by sending a message, such as an NAS or an RRC message. 
         [0075]    In an embodiment, MME or SGSN functionality may be located in a local gateway. The local gateway may host a part of the total MME responsibilities that may be in the CN. Some of the local MME functions may include paging for SIPTO traffic and termination of a signaling point for SIPTO or LIPA and both mobility and session management signaling, for example. The local MME may communicate with the CN&#39;s MME in order to update certain WTRU contexts in the network, such as establishment of new bearers for SIPTO or LIPA traffic and disconnecting of PDN connections, for example. 
         [0076]    The local gateway or any other local functionality, such as the traffic offload point function, for example, may maintain some mobility management contexts for the WTRUs such as an S-TMSI, M-TMSI, or P-TMSI and an international mobile subscriber identity (IMSI), routing area identifier (RAI) and tracking area identifier (TAI), for example. The local functionality may be useful where the local functionality may contact the WTRU via paging to provide information to nodes such as the RNC or RRC, for example. 
         [0077]    The WTRU may also deactivate idle mode signaling reduction (ISR) when LIPA traffic on a home or enterprise network is started or when SIPTO traffic on a home cell, enterprise CSG cells or macro cell is started. The deactivation may avoid the need to page the WTRU if the WTRU reselects between two systems and if the LIPA/SIPTO traffic cannot be routed to the target system. 
         [0078]    In addition, the WTRU may initiate a tracking or routing area update procedure to inform the MME or SGSN, respectively, that the WTRU has left its previous cell where LIPA or SIPTO was activated. This may require a new update type. The network and the WTRU may deactivate all related contexts and IP addresses. Alternatively, the network and the WTRU may maintain all related contexts and IP addresses. If the related contexts and IP address are maintained, the WTRU may not be paged for LIPA/SIPTO if the traffic cannot be routed to the WTRU&#39;s current location. However, if the SIPTO or LIPA traffic may be routed across the RAN, the WTRU may not deactivate ISR when SIPTO or LIPA is initiated. The WTRU may decide on activation or deactivation based on a configuration or on indications from the network. 
         [0079]    Although features and elements are described above in particular combinations, one of ordinary skill in the art will appreciate that each feature or element can be used alone or in any combination with the other features and elements. In addition, the methods described herein may be implemented in a computer program, software, or firmware incorporated in a computer-readable medium for execution by a computer or processor. Examples of computer-readable media include electronic signals (transmitted over wired or wireless connections) and computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, a read only memory (ROM), a random access memory (RAM), a register, cache memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, and optical media such as CD-ROM disks, and digital versatile disks (DVDs). A processor in association with software may be used to implement a radio frequency transceiver for use in a WTRU, UE, terminal, base station, RNC, or any host computer.