Patent Publication Number: US-2020304409-A1

Title: System and methods for supporting low mobility devices in next generation wireless network

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of 62/315,398 filed on Mar. 20, 2016, the contents of which is hereby incorporated by reference herein. 
    
    
     BACKGROUND 
     In wireless communication a wireless transmit/receive unit (WTRU) may travel from one radio access network (RAN) to another. Legacy systems may not adequately address varying degrees of mobility of a WTRU and the resulting consequences of such mobility. For instance, the mobility of the WTRU may be stationary or it may move minimally and infrequently. Legacy systems may not fully address such mobility in the design, handling, and configuration of wireless networks. 
     SUMMARY 
     A method and system for supporting non-IP data routing for low mobility devices in a next generation wireless network is disclosed. The data routing includes performing non-IP data routing within a 3GPP network and IP data routing outside the 3GPP network. The data routing is performed in an Ingress/Egress GW at the border of the networks, wherein the Ingress/Egress GW translates between non-IP data and IP packets. The Egress GW transforms non-IP data to IP packet by allocating, with help of GW Controller, temporary device IP address to the device and maintains the mapping between the Device ID and the temporary device IP. In the downlink, the Ingress GW transforms IP packets to non-IP data by looking up the device&#39;s Device ID using stored mapping information. The routing path is established within the 3GPP network using SDN-based technology and a Device ID/Service ID combination is used as the routing tag. 
     Additionally, the system and apparatus addresses the different types of mobility of a wireless transmit/receive unit (WTRU) in a network. A radio access network (RAN) may send a request for configuration information to a gateway device including a device ID of a WTRU, a service ID, and a RAN address. Once the RAN receives configuration information from the gateway device including a forwarding table, the RAN may be prepared to receive non-IP data from a WTRU including a routing tag. The routing tag may be based on the device ID of a WTRU and service ID. The RAN may transmit the non-IP data received from the WTRU to the gateway device over a routing path based on the routing tag and a forwarding table where the non-IP data is forwarded on to its detention, such as another WTRU or an Application Server. 
    
    
     
       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  is a system diagram of an example communications system in which one or more disclosed embodiments may be implemented; 
         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 ; 
         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 ; 
         FIG. 2  is a system diagram of an example architecture for GTP-based mobility support in LTE EPC; 
         FIG. 3  is a system diagram of an example architecture for supporting non-IP data routing; 
         FIG. 4  shows an example of a high level data protocol stack for supporting a non-IP data routing architecture; 
         FIG. 5  shows an example of a protocol stack for non-IP data routing; 
         FIG. 6  shows an example method of the selection of different Egress GWs for different non-IP data services; 
         FIG. 7  shows an example of a non-IP data protocol/format (NIDP) data format; 
         FIG. 8  shows an example method for performing incoming non-IP data routing; and 
         FIG. 9  shows an example method for performing fast routing path modification. 
     
    
    
     DETAILED DESCRIPTION 
       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. 
     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, an Internet of Things device, a sensor, a server, a collection of computers such as for cloud computing, 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 core network  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 eNode B, a Home Node B, a Home eNode B, a site controller, an access point (AP), a wireless router, and the like. While the base stations  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 Radio Access Network (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. 
     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). 
     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). 
     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). 
     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 1×, 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. 
     The base station  114   b  in  FIG. 1A  may be a wireless router, Home Node B, Home eNode B, or access point, for example, and may utilize any suitable RAT for facilitating wireless connectivity in a localized area, such as a place of business, a home, a vehicle, a campus, and the like. In one embodiment, the base station  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 . 
     The RAN  104 , and more specifically one or more nodes or elements in 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. 
     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. 
     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  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  130 , removable memory  132 , a power source  134 , a global positioning system (GPS) chipset  136 , and other peripherals  138 . It will be appreciated that the WTRU  102  may include any sub-combination of the foregoing elements while remaining consistent with an embodiment. 
     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. 
     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. 
     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), etc.), 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. 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. 
     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  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 . 
     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.    
     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. 
     The core network  106  shown in  FIG. 1C  may include a mobility management entity gateway (MME)  142 , a serving gateway  144 , and a packet data network (PDN) gateway  146 . While each of the foregoing elements are depicted as part of the core network  106 , it will be appreciated that any one of these elements may be owned and/or operated by an entity other than the core network operator. 
     The MME  142  may be connected to each of the eNode-Bs  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 eNode Bs  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-eNode B 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. 
     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 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. 
     Other network  112  may further be connected to an IEEE 802.11 based wireless local area network (WLAN)  160 . The WLAN  160  may include an access router  165 . The access router may contain gateway functionality. The access router  165  may be in communication with a plurality of access points (APs)  170   a ,  170   b . The communication between access router  165  and APs  170   a ,  170   b  may be via wired Ethernet (IEEE 802.3 standards), or any type of wireless communication protocol. AP  170   a  is in wireless communication over an air interface with WTRU  102   d.    
       FIG. 2  shows an example architecture for Gateway Tunnel Protocol (GTP)-based mobility support in LTE Evolved Packet Core (EPC). The mobility management framework of EPC is designed around the “always-on” principle and is built on the network-controlled mobility protocol GTP. In one example there may be data flow  213  back and forth between a WTRU  210  at location a to a PDN  202 . In the example architecture as shown in  FIG. 2  there may also be an MME  203  and S-GW  205  that assist in the data flow  213 . The WTRU  210  is attached to a mobility anchor, such as a P-GW  201 , which is a centralized network entity and remains attached to the same point when the WTRU  210  moves around. The WTRU  210  is allocated an IP address  212  by the P-GW  201  and this IP address  212  is used as the identifier and address locator for WTRU  210 . GTP tunnels  206   a ,  206   b , and  204  are established between the mobility anchor and the WTRU&#39;s serving access network, such as eNB  208   a  and  208   b . When WTRU  210  moves in the network from location a to location b and triggers the serving access network changes, such as the inter-eNB in-session handover or the Tracking Area Update that involves S-GW reallocation, the network will manage/move the WTRU&#39;s  210  GTP tunnels to “follow” the WTRU&#39;s current location, such as going from GTP  208   a  at location a to GTP  208   b  at location b. As long as the incoming data flow  213  travels through the established GTP tunnels  204  and  206   b  after the move to location b, it will find the destined WTRU  210 . The WTRU&#39;s IP address  212  remains unchanged when moving across access networks and the WTRU  210  is unaware of the tunnel management. 
     Data routing within a Third Generation Partnership Project (3GPP) network follows the established GTP tunnels as shown in  FIG. 2 . WTRU&#39;s GTP tunnels are identified by GTP Tunnel IDs in a 3GPP network. For example, for the uplink between the eNB  208   a  and S-GW  205  a GTP Tunnel ID “UL S1-TEID” may be assigned to the GTP tunnel  206   a  and for the uplink between the S-GW  205  and P-GW  201  a GTP Tunnel ID “UL S5-TEID” may be assigned to the GTP tunnel  204 . The Tunnel IDs are carried in the header of each GTP-U data so the GWs can easily find out the next hop for the data routing. 
     The mobility framework as discussed in the example of  FIG. 2  may be utilized and optimized for human communication where a WTRU is a smartphone and assumes the smartphone may need to roam at a certain speed. One goal of the system design may be to achieve service continuity when a WTRU is mobile at high speeds. There is no differentiation in mobility support for WTRUs that have various mobility levels. A universal mobility framework is applied to all WTRUs, regardless of their mobility levels or whether they need service continuity or not. 
     In the discussion for mobility framework of a next generation network, the requirement for “mobility on demand” is emphasized. There are at least two use cases for mobility on demand. In a first use case, WTRUs may comprise different device types and uses, and may have different mobility levels (e.g., some WTRUs may move at high speed while other WTRUs may follow nomadic patterns or may be stationery) and different mobility levels may require different mobility support. In a second use case, different applications and services running on a WTRU may require different mobility support. For example, some applications may handle the mobility events on the application layer and would not need the traditional network layer mobility support. 
     In order to support “mobility on demand” the following considerations may need to be addressed: how to support mobility on demand and different types of mobility; the types of mobility a system should support (e.g. high mobility, medium mobility, low mobility, no mobility and mobility on demand); how to determine the type of WTRU mobility (e.g. by what characteristics/method); and/or how to obtain information (e.g. application&#39;s needs, WTRU capabilities, used services) in order to determine the appropriate type of mobility of the WTRU. 
     Examples of different “mobility levels” or mobility may include any one or a combination of the following: mobility supported over a given area within a single RAN node; a mobility level supported within a single RAN node (i.e. equivalent to an eNodeB); mobility supported between RAN nodes in a RAN registration area (i.e. equivalent to a TA in EPC); mobility supported in the service area of a control plane or user plane CN entity (i.e. equivalent to an MME pool area or a Serving GW service area in an EPC); mobility supported within a given RAT or combination of RATs integrated on the RAN level (e.g. LTE and 5G RAT); or mobility supported between more than one access technologies. 
     In summary, the mobility framework in next generation network may need to address different mobility levels and provide appropriate solutions. In particular, the mobility support for low mobility WTRUs or stationary WTRUs may need to be accommodated in a next generation network. 
     Within a GTP-based 3GPP network, data routing follows pre-established GTP tunnels. The tunnel IDs are included in each GTP-U header so GWs are able to easily find the next hop. 
     Alternative methods compared to GTP based mobility management may be used for low mobility WTRUs because IP anchoring may not be necessary in situations where WTRUs are stationary or only move within a very limited area, especially when the WTRUs may not require perfect service continuity. Additionally, establishing GTP tunnels may require a significant amount of signaling and there may be a problem if there are a high number of low mobility WTRUs. Data routing mechanisms within a 3GPP core network for low mobility WTRUs should be addressed because GTP is unlikely to be used for mobility management for low mobility WTRUs and when GTP tunnels are not available. 
     For IP data routing, alternative routing mechanisms may be used for low mobility WTRUs. It is possible that one or more low mobility WTRUs may also use non-IP data communication. For example, one or more low mobility WTRUs may be low cost devices that do not have an IP stack. Also, an IP packet may have a large header overhead which may not be desirable for a large amount of low mobility WTRUs. As a result, methods and systems as discussed herein may be used to support non-IP data routing for low mobility WTRUs. 
     In one embodiment routing data may be based on a non-IP address within a 3GPP network. In such an embodiment the non-IP data may still be routed over an IP network because data infrastructure is mostly IP based outside a 3GPP network. Such an embodiment may follow general principles of the next generation core network, including 5G and New Radio technologies, such as complete CP/UP separation, virtualized network functions, network slicing, and software defined networking (SDN) based routing. Also, such an implementation may be efficient and not incur much overhead. 
     In one example data routing may be addressed by dissecting it into two sections: non-IP routing within a 3GPP network and IP routing outside the 3GPP network. An Ingress/Egress GW at the border of these two sections may translate between non-IP data and IP packets. The Ingress/Egress GW may transform non-IP data to IP packets by allocating, with the help of a GW Controller, temporary device IP addresses to WTRUs and maintain mapping between a Device ID and the temporary device IP. In the downlink, the Ingress/Egress GW may transform IP packets to non-IP data by looking up a WTRU&#39;s Device ID using stored mapping information. In one example a routing path within the 3GPP network may be established using SDN-based technology and the Device ID/Service ID combination is used as the routing tag. 
       FIG. 3  shows an example architecture for supporting non-IP data routing for a non-IP WTRU. In  FIG. 3  the whole routing path is divided into two parts: a non-IP routing part  311  and an IP routing part  312 . The non-IP routing part  311  is within a 3GPP network, between the RAN  304  (i.e. a node or element) or Access Gateway and the Ingress/Egress GW  307 . The IP routing part  312  is between the 3GPP Ingress/Egress GW  307  and the destination, such as a Service/Application Server  310  or a peer WTRU (not shown) of the outside PDN  309 . WTRUs  301   a - d  may send non-IP data through the non-IP routing domain part  311  and an IP routing domain part  312  to a destination such as a Service/App Server  310 . 
     In  FIG. 3  the architecture for non-IP data routing assumes the infrastructure network outside the 3GPP network is IP-based. However, if the infrastructure network outside the 3GPP network is non-IP based (e.g., it uses a different non-IP protocol than that within a 3GPP network), the same systems and methods described herein may be applied. 
     As seen in  FIG. 3 , each non-IP WTRU  301   a - d  is assigned an Ingress Gateway  307 , which receives all the incoming data from outside a PDN  309  and forwards it to a non-IP WTRU such as  301   a , and an Egress Gateway  307 , which terminates all the outgoing data from the non-IP WTRU  301   a  and forwards it to the destination outside the PDN  307 . The Ingress/Egress GW  307  may be separate (not shown) or combined in a physical entity. 
     The Ingress/Egress GW  307  of the non-IP WTRU  301   a  is assigned by the GW Controller  306 . The GW Controller  306  may also select one or more other routing GWs  305  to form a non-IP routing path between the RAN  304  and the Ingress/Egress GW  307 . The GW Controller  306  may also configure, possibly using SDN-based APIs, routing tables in the other routing GWs  305  that are in the non-IP routing path to make sure that the non-IP data is routable between the RAN  304  and the Ingress/Egress GW  307 . The GW Controller  306  may need to query a Service DNS  308  to obtain the IP of the destination Service/App Server  310  in the outside PDN  309 . 
     The non-IP WTRUs  301   a  &amp;  301   b  may directly connect to the network or indirectly connect through a Capillary GW to the network such as WTRUs  301   c  &amp;  301   d . The non-IP WTRUs  301   a - d  may register with the local RAN  304  or the Mobility Control Function  303  in the core network. After the device registration, the RAN  304  or the Mobility Control Function  303  interacts with the selected GW Controller  306  to establish the non-IP routing path. 
     One or more of the main functions described in relation to  FIG. 3  may be instances of virtualized network functions, and the functions may be organized into a network slice that is targeted for non-IP services. Further, the GWs&#39; control plane functions and user plane functions may not be separated as illustrated in  FIG. 3 , but instead may reside in one GW entity. 
     Also in  FIG. 3 , at the boundary of the non-IP routing part  311  and the IP routing part  312 , the non-IP data may be transformed to IP data or vice-versa by the Egress/Ingress GW  307 , possibly with the control of the GW Controller  306 . 
       FIG. 4  shows an example of a non-IP data protocol/format (NIDP) data format. A NIDP may be defined so that the forwarding tables in the routing path may be established following the protocol. The NIDP  401  header may contain the Service ID  403  or the combination of the Device ID  402  and Service ID  403  as the routing tag. To enable non-IP data forwarding based on the NIDP header  401 , the Device ID and Service ID should be included in each non-IP data from a WTRU. Service priority information  404  may also be included in the NIDP header  401 . The NIDP header  401  may be followed by the NIDP payload  405  comprising of an application data payload  406 . A more complex header design than the example NIDP header shown in  FIG. 4  may include security or ciphering information. 
       FIG. 5  shows an example of a high level data protocol stack for supporting a non-IP data routing architecture such as that shown in  FIG. 3 . WTRU  501  may have an App  502  that must communicate data to the App server  516  through a RAN  505  and an Ingress/Egress GW  510 . SDN-based routing, such as Openflow routing, may be used for the non-IP data routing part within a 3GPP core network. Each gateway may have a separate non-IP data routing or forwarding table. The WTRU  501  may also have NIDP  503  and RAN Air Interface  504 . The WTRU  501  communicates over an air interface  520  with the RAN  505 . A GW Controller may configure each GW in the path, from the RAN  505  to the selected Egress GW  510 , with a forwarding table entry that points the data to the proper next hop. The Ingress/Egress GW  510  may have the following protocol stack layers: App  513 , NIDP  511 , UDP  514 , Layer  2  or Layer  3   512 , IP  515 , and Layer  2   520  and may comprise any technology that can carry IP over it, such as MPLS, ATM, and the like. The App Server  516  may have the following protocol stack layers: App  517 , UDP  518 , IP  519 , and Layer  2   521  and may comprise any technology that can carry IP over it, such as MPLS, ATM, and the like. 
       FIG. 6  shows an example method for performing outgoing non-IP data routing. For this example, it is assumed that a non-IP WTRU has already selected the network/network slice and the RAN. 
     At  607 , the non-IP WTRU  601  registers with the network or network slice. Either the RAN  602  or certain Mobility Control Function (MCF) in the core network may handle such a registration. The registration identifies the Device ID, together with its location to the network. 
     At  608 , upon receiving the WTRU&#39;s  601  registration request, the RAN  602  or MCF may select a GW Controller  603  and request the GW Controller  603  to establish the non-IP data routing path for the WTRU  601  which may include information like the Device ID, Service ID, RAN address, and the like. 
     At  609 , the GW Controller  603  selects the Egress GW  604  and any other necessary routing GWs. At  610  the GW Controller  603  also configures those GWs (including the RAN  602  or access gateway) with Device-ID based forwarding tables; the forwarding tables may comprise mappings between a Device-ID and the next hop address such that a GW can determine the next hop address by looking up the Device ID in the table. 
     At  611  the WTRU  601  sends non-IP data to the RAN  602 , the NIDP data header provides the Device ID which will be used by the routing GWs to forward the data to the Egress GW  604 . 
     At  612  the non-IP data arrives at the Egress GW  604 , and if the Egress GW  604  has no routing context for the Device ID, then at  613  the Egress GW  604  makes a request for a temporary IP address for the WTRU  601  to the GW Controller  603 . At  614  the GW Controller  603  assigns the requested temporary IP address to the WTRU  601 . At  615  the GW Controller also queries the DNS server  605  using the service ID that is provided in the NIDP data to obtain the destination IP address. 
     At  616  the Egress GW  604  receives an IP assignment response from the GW Controller  603 , containing information such as the temporary device IP address, destination IP, and the like. At  617  the Egress GW  604  uses this temporary device IP address and the destination IP to transform the NIDP data into an IP routable packet, and then at  618  the Egress GW  604  forwards the IP packet to the destination server  606 . 
     In view of the process as explained in  FIG. 6 , one purpose of device registration may be for a WTRU to provide the network with the “Device ID” and “Service ID” of the WTRU which will form the routing tags to be used in non-IP data routing. Device registration may also identify the WTRU&#39;s location, e.g. in the form of the connected RAN or access gateway&#39;s Layer  2  address. The location information may be used by the GW Controller to configure the route for the incoming data. 
     The “Device ID” and “Service ID” could take many forms: it could be a text string, an URI, IMEI number, a public cryptography key (as considered in relation to the Host Identity Protocol (HIP)), or the like. 
     Note that the WTRU may indicate one or multiple Service IDs in the registration and that priorities may also be linked with each Service ID. 
     Besides the Device ID and Service ID(s), other necessary capability indications such as “low-mobility” indication, “non-IP data device” indication, “outgoing data only” flag, “incoming data only” flag and “outgoing and incoming data” flag may also be signaled to the network during the registration. The WTRU may also report its reachability related parameters such as Power Saving Mode or extend DRX settings. 
     Device registration may be handled by the RAN or other network entities such as Mobility Control Function. There may also be other procedures such as device authentication, authorization procedure combined with the device registration procedure. 
       FIG. 7  shows an example of the selection of different Egress GWs for different non-IP data services. Each non-IP WTRU  760  should to be assigned an Egress GW, such as Egress GW  706  or  708 . An Egress GW may sit at the border between 3GPP core network and outside PDN as shown in  FIG. 3 . An Egress GW terminates the non-IP data transmission and transforms it into IP routable packets and forwards the packets to the destination in the IP network, as discussed herein. 
     The selection of an Egress GW, such as Egress GW  706  or  708 , may be performed by the GW Controller  701 , or other network entities/functions such as Mobility Control Function. In one embodiment the GW Controller  701  performs this task since the GW Controller  701  also needs to select other routing GWs between the RAN  703  and the selected Egress GW, as well as configure the routing tables in those GWs. If other entities/functions perform the Egress GW selection, the GW Controller  701  needs to be informed of the address of the selected GW. 
     The selection of the Egress GW may be triggered by device registration or some other procedure. Upon device registration, the RAN  703 , or the MCF (not shown), may send a “routing request” to the GW Controller  701  and then the GW Controller  701  will select the Egress GW, such as Egress GW  706  or  708  and other necessary routing GWs between the RAN  703  and the selected Egress GW. The selection of the GWs may also be delayed until the WTRU  702  sends its first non-IP data. 
     The selection of an Egress GW may be based on the Service ID received from the routing request. It is possible that an Egress GW may not support all non-IP data services but a fraction of them, so the selected Egress GW should cater for the indicated Service ID. If multiple Service IDs are indicated, the GW Controller may select the same or different Egress GWs for each Service ID. The GW Controller  701  may also need to query the DNS for the IP address of the Device ID before it may select the Egress GW. 
     In one embodiment when the WTRU  702  sends non-IP data with Service ID 1   710 , the non-IP data is routed by the GW Controller through Routing GW 1   704 , Routing GW 2   705 , and arrives at the Egress GW  706  where it will be sent off to its ultimate destination using an IP service. In another embodiment when the WTRU  702  sends non-IP data with Service ID 1   709  the non-IP data is routed by the GW Controller  701  to through Routing GW 1   604 , Routing GW 2   707 , and arrives at the Egress GW  708  where it will be sent off to its ultimate destination using an IP service. 
     In one embodiment, there may be a process for assigning a temporary device IP and performing Destination IP query. When NIDP data arrives at a Egress GW, the Egress GW may check whether it has the context for the Device ID and whether an IP address is available. If not, the Egress GW may request the GW Controller to assign a temporary IP address for that WTRU. The GW Controller may have its own IP address pool for this function. It may also utilize another entity such as a DHCP server for this purpose. 
     The GW Controller may also be requested to resolve the destination IP for the Service ID by utilizing a DNS service. The transport port numbers (e.g., UDP port) may also need to be obtained. 
     It is also possible that the GW Controller has already performed temporary IP allocation and destination IP resolution when the routing request is received for the WTRU, and stored them with the WTRU&#39;s context. The GW Controller will return this information to the Egress GW when requested. 
     The GW Controller may modify or release the WTRU&#39;s temporary IP upon certain conditions. For example, if the Ingress or Egress GW reports a long time of inactivity for the WTRU the GW Controller may release the temporary IP assignment and use it for another WTRU. The WTRU may or may not receive a network indication of the temporary IP address change depending on whether the application server can handle such an IP change. 
     It is also possible that the Egress GW may perform the IP address allocation and destination IP resolution on its own, without the help of the GW Controller. 
     In another embodiment, the assignment of a source IP address by the GW Controller node may be based on the service type or service ID included in the IP assignment request message. The GW Controller node may check the service ID included in the request message where the source IP is being requested and, in turn, the urgency or priority of the request acquired from this information. The IP address version (IPv4 or IPv6), type of IP address (temporary address or permanent IP address), and QoS associated with this IP address/connection (DSCP value) may then be decided by the GW Controller. 
     If the decision by the GW node is to assign a temporary IP address, some other parameters may need to be defined to clarify the scope of a temporary IP address, such as the validity of the temporary IP address. The Egress GW may be notified about the length of temporary IP address presence. The notification may be in terms of time units (e.g. seconds or minutes) or alternatively it may be in terms of a WTRU connection state where a particular IP address may be used as long as the WTRU is in connected mode. A new IP address may need to be requested every time the WTRU experiences a state transition between idle and connected modes. 
     Alternatively, the GW Controller may decide to assign a permanent IP address for some Service IDs or type. Low latency type services, such as health monitoring applications and V2X services, are some instances where the GW Controller may assign a permanent IP address. The permanent IP address may be valid during the life time of the device registration. As long as the WTRU is attached or registered to the network, the GWs may be able to use the same permanent source IP address for all the outgoing packets for that particular WTRU. 
     With the assigned temporary device IP address, the resolved destination IPs, and UDP port numbers, the Egress GW may transform the received NIDP data into IP packets, using the device IP as the source IP address, and forward them to the outside IP network. 
       FIG. 8  shows an example of a method for performing incoming non-IP data routing. If the WTRU  801  has sent outgoing data to the outside IP network, either to an application server or a peer WTRU  801 , the incoming data should have the WTRU&#39;s temporary IP address as the destination address. If the WTRU  801  has not sent outgoing data before, there is no way for the server or other peer WTRUs to send IP packet to the 3GPP network. In this latter case the server may need to trigger the non-IP WTRU  801  to send outgoing data first, such as at  805  where the WTRU  801  sends an application registration message to the RAN  802  including the Device ID and the Service ID. 
     At  806  the RAN  802  sends a routing request to the GW Controller  803  with the information received in the application registration message as well as the RAN address. At  807  the GW Controller  803  may assign the temporary device IP and resolve the destination IP. At  808  this mapping information may then be sent to the Ingress GW  804  from the GW Controller  803 . In one example the mapping information may include a concordance of Device ID/Service ID to Device IP/Destination IP. At  809  the Ingress stores this mapping information for use when information destined for the WTRU  801 . 
     At  810  incoming data may come in for a non-IP WTRU  801  at the Ingress GW  804 . The Ingress GW  804  may be implicitly selected after the temporary IP assignment as discussed herein. In one embodiment the Ingress GW is the same GW as the Egress GW, but in another embodiment a separate Ingress GW may also be possible. Other routing GWs (not shown) between the RAN  802  and the Ingress GW  804  for incoming data may also be selected together with the GW selections for outgoing data. Similarly, routing GWs for incoming data may or may not be the same as the routing GWs for the outgoing data. In other words, the routing path for incoming data may or may not be identical as the path for outgoing data. 
     The forwarding table configuration in the GWs for incoming data may also be performed together with the configuration for outgoing data. If this is not the case and a GW in the routing path cannot find the forwarding entry for the received incoming data, the GW may request the GW Controller  803  to update the forwarding table. 
     Also at  810  when the IP packets that carry the non-IP application data payload arrive at the Ingress GW  804 , the Ingress GW  804  makes a reverse mapping at  811  from the IP header information (source IP address, destination IP address) to the Device ID and Service ID. The mapping information may be created at  809  when the temporary device IP address is assigned and stored in the Ingress GW  804 . Using the Device ID and Service ID, at  812  the Ingress GW  804  may transform the receiving IP packets into NIDP data format and forward them to the RAN  802  following the pre-configured routing path. At  813  the RAN  802  completes the process by delivering the incoming data that was converted to NIDP data to the non-IP WTRU  801 . 
     In another embodiment, IP address assignment service may be exposed to the Application Server. If the Application Server has a packet destined to a particular WTRU and is unaware of the destination IP address, the Application Server may request the destination IP address via an API message through an exposure function. The exposure function may then contact the GW Controller to request the WTRU source IP address. The GW function may assign the WTRU a source IP address upon receiving this request from the exposure function. The newly assigned source IP address may then be sent to the exposure function by the GW Controller. An API response message may provide the IP address to the Application Server. When the Application Server sends the DL IP packet, it may include the received IP address as the destination address in the IP header of the packet. This embodiment assumes the exposure layer is cognizant of the mapping between the external Device ID used by the Application Server in the API request and the Device ID and/or Service ID. The exposure function&#39;s message for IP address assignment may include the internal Device ID and the service ID based on the mapping. 
     When a non-IP WTRU moves from its previously connected RAN to a new RAN, the data routing needs to be modified so that the data arrives at the new RAN. The new RAN may trigger the GW Controller to modify the outgoing and incoming routing after the WTRU registers with the new RAN, similar to what has been described herein. However, one drawback of this method is that the routing path modification by the GW Controller may introduce significant delay and cause disruption of service. 
     Accordingly, in one embodiment when a WTRU moves to a new RAN, the WTRU may continue to use most of the original routing path that had already been established between the previous RAN and Egress/Ingress GW, and only the hop between the previous RAN and the first routing GW is changed to the hop between the new RAN and the first routing GW. In this embodiment the “first routing GW” may be defined as the closest GW in the routing path, or if defined from the perspective of the Ingress GW to the RAN, it is the last routing GW in the path. 
       FIG. 9  shows an example method for performing fast routing path modification when a WTRU moves to a New RAN from a Previous RAN.  906  shows the previous routing path of non-IP data for WTRU  901  prior to the move to a new RAN  903 . At  907 , for outgoing data, the new RAN  903  receives the first routing GW address from device registration by the WTRU  901  and uses it at  908  to establish its own mapping of a routing entry and point it to the first routing GW  904  for the WTRU  901 . Alternatively, the New RAN  903  retrieves the address of the WTRU&#39;s  901  first routing GW from the Previous RAN  902 . At the first routing GW  904 , the source of the previous hop (being either the Previous RAN  902  or the New RAN  903 ) does not matter because the routing is filtered with the Device ID and Service ID tag so the data is correctly forwarded to the destination without any change. 
     At  910  when the first routing GW  904  receives the outgoing data from a different RAN address, the first routing GW  904  modifies its downlink routing table to point it to the corresponding new RAN address. This is because the same GW is used as the “first routing GW” for both outgoing and incoming data and other routing GWs in the path may still be different for incoming and outgoing data. For the incoming data, however, the routing table at the first routing GW  904  is modified so the routing entry for the Device ID/Service ID points to the New RAN  903  instead of the Previous RAN  902 . At  909 , because the routing entry modification is triggered by the outgoing data, the New RAN  903  may need to send fake outgoing data to trigger routing entry modification instead of waiting for real outgoing data from the WTRU. At  911  the new routing path after the WTRU  901  has switched to the new RAN  903  is complete. 
     The same routing path modification procedure may be repeated when the WTRU moves to another RAN and so on. After a few modifications the original routing path may not be the most optimal path, but it should be acceptable considering that a low-mobility WTRU may roams in a limited area, infrequently, or not at all. 
     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.