Method and apparatus of maintaining forbidden tracking area list

Method and device for maintaining list of prohibited tracking areas

METHOD AND APPARATUS OF MAINTAINING FORBIDDEN TRACKING AREA LIST

The disclosed embodiments generally relate to wireless communication, and more specifically, to a method for maintaining a tracking area (TA) list in a new radio (NR) system.

Over the years, wireless communication networks have grown exponentially. The Long-Term Evolution (LTE) system provides a high peak data rate, low latency, increased system capacity, and low operating cost due to a simplified network architecture. The LTE system, also known as the 4G system, also provides seamless integration with older wireless networks, such as GSM, CDMA, and Universal Mobile Telecommunication System (UMTS). In the LTE system, the evolved universal terrestrial radio access network (E-UTRAN) includes a plurality of evolved nodes that communicate with a plurality of mobile base stations (called user equipment (UE)). eNodeb or eNB). The third-generation mobile communication project (3GPP) network usually includes a mixture of 2G/3G/4G systems. The Next Generation Mobile Network (MGMN) board of directors has decided to focus future NGMN activities on defining the end-to-end requirements of the 5G New Radio (NR) system.

When the UE is connected, the network is in the small base station Know the location of the UE at the (small cell) level. When the UE is in an idle state, the website knows the location of the UE at the tracking area (TA) level. A tracking area code (TAC) is a unique code assigned to a TA by each operator, and a tracking area identifier (TAI) is composed of a PLM ID and a TAC. When the UE is connected to the LTE/NR network, the UE obtains a TAI list. This list shows the tracking area in which the UE is located and in which the UE can travel. The LTE/NR network needs to have updated location information about the UE in an idle state to find out which TA a specific UE is located in. Each time the UE moves between TAs, the UE notifies the LTE/NR network of its current location by sending a tracking area update (TAU) request message in EPS or a registration request message in 5GS.

Mobility management in the 5G NR system has two types of TAI lists-allowed or disallowed TAI lists and prohibited TAI lists. When the UE connects to the network and receives an error during the registration process, the TAI is added to the prohibited TAI list. Maintain the prohibited TAI list in the UE, and when the UE is turned off, or when the universal integrated circuit card (universal integrated circuit card, UICC) containing SIM/USIM is removed, the UE resets the prohibited TAI list, or The UE periodically resets the prohibited TAI list. In the subsequent registration process, the network can provide the UE with the allowed tracking area. If one or more tracking areas in the prohibited TAI list are received from the network, the allowed tracking areas can be removed from the prohibited TAI list. However, if the UE is registered for emergency services, the tracking area may not be removed. In addition, the network can provide the allowed tracking area to the UE via a configuration update command. A suitable process for the maintenance and updating of the prohibition of the TAI list is required.

A method of maintaining an appropriate TAI list is disclosed. The UE receives a service area list including one or more allowed TAIs. The service area list can be carried by a configuration update command or a registration acceptance message in response to a registration request. The UE compares whether any of the allowed TAIs has a match in the forbidden TAI list. Therefore, the UE removes any allowed TAI with a matching TAI from the list of forbidden TAIs. In one embodiment, the UE sends a registration request message to initiate a registration process. If the registration process is successful, the UE receives a registration acceptance message, which also carries a service area list. The UE may remove the allowed TAI with a matching TAI from the forbidden TAI list. However, if the UE is registered for emergency services, the UE will not remove the allowed TAI from the forbidden TAI list.

In one embodiment, the UE maintains an identification list of prohibited areas in a mobile communication network. The prohibited TAI list includes a TA list in which the UE is prohibited from receiving services from the network. The UE receives a service area list from the network. The service area list includes at least one allowed TAI. When a removal condition is met, the UE removes the allowed TAI from the forbidden TAI list. The removal condition includes that the UE finds a match of the allowed TAI in the forbidden TAI list. In one embodiment, the service area list is carried by a configuration update command message transmitted from the network. In another embodiment, the service area list is carried by a registration acceptance message from the network in response to a registration request message. If the UE is registered for emergency services including or not including the PDU session, the UE does not remove the allowed TAI from the forbidden TAI list.

With the method of the present invention, it is judged whether the removal condition is satisfied, When the removal condition is met, removing the corresponding TAI from the prohibited TAI list can better maintain the prohibited TAI list.

Other embodiments and advantages are described in the detailed description below. The content of the invention is not intended to limit the present invention, and the present invention is limited by the scope of the patent application.

<p>100, 201, 302, 402: network</p><p>110: core network</p><p>111: Application Server</p><p>113: Packet Data Network Gateway</p><p>114, 301, 401: User Equipment UE</p><p>115, 211: base station BS</p><p>116: Serving GW</p><p>117: MME/AMF</p><p>120: wireless access network</p><p>140: UE maintains a list of prohibited TAIs</p><p>202, 212: memory</p><p>203, 213: Processor</p><p>204, 214: RF transceiver</p><p>205, 215: Antenna</p><p>210, 220: Program instructions</p><p>221, 231: Registered circuit</p><p>222: TAI list maintenance circuit</p><p>223, 233: configuration and control circuit</p><p>232: Action Management Circuit</p><p>260, 280: Agreement Stack</p><p>270: System modules and circuits</p><p>290: Control function modules and circuits</p><p>311~361, 411~451, 501~524, 601~603: steps</p>

The drawings show embodiments of the present invention, in which the same symbols indicate the same elements.

Figure 1 shows an exemplary EPS/5GS network that supports UE registration and maintenance of the Tracking Forbidden Area Identity (TAI) list according to a novel aspect.

Figure 2 shows a simplified block diagram of a user equipment (UE) consistent with an embodiment of the present invention.

Figure 3 shows a first embodiment of adding or removing TAI from the prohibited TAI list according to a novel aspect.

Figure 4 shows a second embodiment of adding or removing TAI from the prohibited TAI list according to a novel aspect.

Figure 5 shows a detailed flow chart of the UE maintaining the prohibited TAI list in the LTE/NR network according to a novel aspect.

Figure 6 is a flowchart of a method for the UE to maintain a list of prohibited TAIs according to a novel aspect.

Reference will now be made in detail to some embodiments of the invention, examples of which are shown in the accompanying drawings.

Figure 1 shows an exemplary 4G LTE or 5G New Radio (NR) 100 network that supports UE registration and maintenance of the Tracking Forbidden Area Identity (TAI) list according to a novel aspect. The LTE/NR network 100 includes an application server 111, which provides various services by communicating with a plurality of UEs including a user equipment (UE) 114. In the example in Figure 1, the application server 111 and the packet data network gateway (PDN GW or P-GW) 113 are part of the core network CN 110. The UE 114 and its serving base station BS 115 are part of the radio access network RAN 120. The RAN 120 provides radio access for the UE 114 via radio access technology (RAT). The application server 111 communicates with the UE 114 through the PDN GW 113, the serving GW 116, and the BS 115. The mobility management entity (MME) or access and mobility management function (AMF) 117 communicates with the BS 115, the serving GW 116 and the PDN GW 113 for wireless in the LTE/NR network 100 Access and mobile management of access devices. Via different RAT/CN, UE 114 can be equipped with one or more radio frequency (RF) transceivers for different application services. The UE 114 may be a smart phone, a wearable device, an Internet of Things (IoT) device, a tablet computer, and the like.

EPS and 5GS networks are packet-switched (PS) Internet Protocol (IP) networks. This means that the network delivers all data services in IP packets and provides users with always-connected IP connectivity. When the UE joins the EPS/5GS network, the Packet Data Network (PDN) address (that is, the address that can be used on the PDN) is allocated to the UE for its connection to the PDN catch. EPS refers to the "IP access connection" of the UE as an evolved packet system (EPS) bearer, which is the connection between the UE and the P-GW. The P-GW is a preset gateway used for the UE's IP access. EPS has defined a default EPS bearer to provide always-on IP connectivity. The UE can establish additional data radio bearers for data communications. However, in some cases, the UE may receive services from the network without establishing a dedicated PDN connection.

When the UE is turned on, it searches for the network to connect to. Once the UE selects the desired network, it will try to access the network and try to register with the network. In order to facilitate the network selection process, the UE may have an operator-controlled PLMN selector list and a user-controlled PLMN selector list stored on the SIM/USIM card. The UE can use all information related to network selection stored on the SIM/USIM, such as HPLMN, operator-controlled PLMN selector list, user-controlled PLMN selector list, and prohibited PLMN list. When the network rejects the UE's registration attempt, the PLMN identification is written into the list of prohibited PLMNs stored in the data archived on the SIM/USIM. If successful registration is achieved on the PLMN in the forbidden PLMN list, then the above-mentioned PLMN identification is removed from the list. The prohibited PLMN list is used to avoid unnecessary registration attempts.

Except for PLMN, the network knows the location of the UE in the tracking area (TA). The tracking area identifier (TAI) is composed of a PLMN ID and a tracking area code (TAC). The action management in the 5G NR system has two types of TAI lists-including a service area list that allows or disallows a TAI list and a forbidden TAI list. When the UE connects to the network and receives an error during the registration process, a TAI is added to the prohibited TAI list. Maintain a list of prohibited TAIs in the UE, and reset the prohibition by the UE when the UE is turned off or when the UICC including SIM/USIM is removed TAI list, or periodically reset the prohibited TAI list. In the subsequent registration process, the network can provide the UE with the allowed tracking area. If one or more tracking areas in the list are received from the network, the tracking areas can be removed from the prohibited TAI list. However, if the UE is registered for emergency services, the tracking area may not be removed. In addition, through the configuration update command, the network can provide the UE with the allowed tracking area.

According to a novel aspect, a method of maintaining an appropriate tracking prohibited area identifier (TAI) list is disclosed. As indicated by 140 in Figure 1, UE 114 maintains a list of prohibited TAIs. The UE 114 receives a service area list or a tracking area list including one or more allowed tracking areas from the MME/AMF 117. The service area list can be carried by a configuration update command or a registration acceptance message in response to a registration request. The UE 114 compares whether any allowed tracking area has a matching TAI in the forbidden TAI list. Therefore, the UE 114 removes any allowed tracking area with a matching TAI from the prohibited TAI list. In a specific embodiment, the UE 114 sends a registration request message to the MME/AMF 117 to initiate the registration process. If the registration process is successful, the UE 114 receives a registration acceptance message, which may also carry a service area list with one or more allowed tracking areas. The UE 114 may remove the allowed tracking area with a matching TAI from the prohibited TAI list. However, if the UE 114 is registered for emergency services with/without PDU callback, the UE 114 will not remove the allowed tracking area from the forbidden TAI list.

Figure 2 shows a simplified block diagram of a wireless device (such as the UE 210 and the network entity 211) consistent with the embodiment of the present invention. The network entity 211 may be a base station combined with MME or AMF. Network entity 211 has an antenna 215. It transmits and receives radio signals. The radio frequency RF transceiver module 214 is coupled with the antenna, receives the RF signal from the antenna 215, converts it into a baseband signal, and sends it to the processor 213. The RF transceiver 214 also converts the baseband signal received from the processor 213, converts it into an RF signal, and sends it to the antenna 215. The processor 213 processes the received baseband signals and wakes up different functional modules to execute the features in the base station 211. The memory 212 stores program instructions 220 and data to control the operation of the base station 211. In the example in FIG. 2, the network entity 211 also includes a set of control function modules and a circuit 290. The registration circuit 231 handles the registration process. The action management circuit 232 handles action management functions. The configuration and control circuit 233 provides different parameters to configure and control the UE.

Similarly, the UE 201 has a memory 202, a processor 203, and a radio frequency (RF) transceiver module 204. The RF transceiver 204 is coupled with the antenna 205, receives the RF signal from the antenna 205, converts it into a baseband signal, and sends it to the processor 203. The RF transceiver 204 also converts the baseband signal received from the processor 203, converts it into an RF signal, and sends it to the antenna 205. The processor 203 processes the received baseband signal and calls different functional modules and circuits to execute the features in the UE 201. The memory 202 stores data executed by the processor and program instructions 210 to control the operation of the UE 201. For example, suitable processor modules include dedicated processors, digital signal processors (DSP), multiple microprocessors, one or more microprocessors related to the DSP core, controllers, microcontrollers, dedicated Integrated circuit (ASIC), field programmable gate array (FPGA) circuit, and other types of integrated circuit (IC) and/or state machines. The software-related processor can be used to implement and configure the features of the UE 201.

UE 201 also includes a set of functional tasks that implement UE 201 Functional modules and control circuits. The protocol stack 260 includes a non-access-stratum (Non-Access-Stratum, NAS) for communicating with the MME or AMF entity connected to the core network, and a radio resource control (Radio Resource Control, for high-level configuration and control). Referred to as RRC) layer, packet data aggregation protocol/radio link control (PDCP/RLC) layer, medium access control (MAC) layer, and physical (PHY) layer. The system module and circuit 270 can be implemented and configured by software, firmware, and/or a combination thereof. When executed by the processor via the program instructions included in the memory, the functional modules and circuits interact with each other to allow the UE 201 to perform the functional tasks and features in the embodiment and the network. In one example, the system module and the circuit 270 include a registration circuit 221 that performs a registration process with the network, a TAI list maintenance circuit 222 that handles the forbidden TAI list addition, removal and resetting in the memory, processing configuration and control parameters The configuration and control circuit 223.

Figure 3 shows a first embodiment of prohibiting the addition or removal of TAI from the TAI list according to a novel aspect. The UE 301 is located in the tracking area of the network with access and mobility management function (AMF) entities. In step 311, the UE 301 maintains a prohibited TAI list including a list of tracking area identifiers. In the 5G NR network, the list of prohibited TAs is also called the list of "5GS roaming prohibited tracking area" or "5GS area service provision prohibited tracking area" list. If the TAI is included in the prohibited TAI list, the UE is prohibited from roaming or receiving services in the corresponding tracking area. In step 321, the UE 301 sends a registration request message to the network 302 to request a service. In step 331, the UE 310 receives a registration rejection message from the network 302, for example, due to network errors. Therefore, in step 341, the UE 301 adds the TAI of the tracking area to the prohibited TAI list.

Subsequently, in step 351, the UE 301 receives a configuration update command from the network 302. When the network recovers from network errors or the network changes its strategy, the network can send such an update command. The configuration update command provides the UE 301 with a list of service areas with allowed tracking areas including one or more TAIs. In step 361, upon accepting this service area list, the UE 301 compares whether one or more TAI values received in the service area list of the allowed tracking area is equal to the TAI value stored in the prohibited TAI list. If one or more matches of TAI values are found in the forbidden TAI list, then in step 361, the UE 301 removes those equal TAI values from the forbidden TAI list.

Figure 4 shows a second embodiment of adding or removing TAI from the prohibited TAI list according to a novel aspect. The UE 401 is located in the tracking area of the network 402, which has an access and mobility management function (AMF) entity. In step 411, the UE 401 maintains a prohibited TAI list including a tracking area identification list. In the 5G NR network. The prohibited TAI list is also called the "5GS roaming prohibited tracking area" list or the "5GS area service provision prohibited tracking area" list. If a TAI is included in the prohibited TAI list, the UE is prohibited from roaming or receiving services in the corresponding tracking area. In step 421, the UE 401 sends a registration request signal to the network 402 to request a service. In this embodiment, the registration type is set to "emergency registration" in the registration request message.

In step 431, the UE 401 receives a registration acceptance message from the network, and the UE 401 successfully registers for emergency services in the tracking area. The registration acceptance message may also carry a list of service areas with allowed tracking areas including one or more TAIs. In step 441, the UE 401 checks whether the UE is registered for emergency services. If the answer is no, then UE 401 is removed from the list of forbidden TAI Remove the matching TAI value. Otherwise, if the answer is yes, the UE 401 does not remove the matching TAI value from the forbidden TAI list. Note that the UE performs emergency registration in two cases. The first case is that the UE does not establish any PDU session (session), and the second case is that the UE establishes one or more PDU sessions for emergency services. In the two cases of emergency registration, the UE will not remove the matching TAI value from the forbidden TAI list.

Figure 5 shows a specific flow chart of the UE maintaining the prohibited TAI list in the EPS/5GS network according to a novel aspect. In step 501, the UE maintains a list of prohibited TAIs. When the reset condition is met, the UE 501 can reset the prohibited TAI list. In step 502, the UE determines whether such a reset condition is satisfied. The reset conditions include: 1) when the UE is turned off, 2) when the universal integrated circuit card (UICC) including SIM/USIM is removed, and 3) when the period of periodic reset is reached (for example, period The period of resetting the prohibited TAI list is 12 to 24 hours. When the current prohibited TAI list is not reset within 12 to 24 hours, the prohibited TAI list is reset. In step 503, if any of the reset conditions are met, the UE resets the prohibited TAI list, and the UE returns to step 501. Otherwise, the UE directly returns to step 501 without resetting the prohibited TAI list.

In step 511, the UE initiates the registration process by sending a registration request to the network. The registration request includes a registration type for receiving normal service or emergency service in the tracking area. In step 512, the UE receives a registration acceptance or rejection message from the network. If the registration is rejected, the UE proceeds to step 513 and adds the TAI of the tracking area to the prohibited TAI list. Note that in addition to the registration process, there are other possibilities to add a TAI to the prohibited TAI list. For example, under the 3GPP specifications, whenever a reason is received, the tracking area is not allowed When the registration rejection message, service rejection message or unregistration request message of "domain", "roaming is not allowed in this tracking area" or "no suitable small base station in the tracking area", the UE will update the prohibited TAI list.

If the registration is accepted, the UE proceeds to step 521 and checks whether the UE has received any service area list including one or more allowed tracking areas. Note that the allowed tracking area can be included in the registration acceptance message from the network in response to the UE registration request, or can be included in the configuration update command message from the network without any UE request. In other words, step 521 can occur directly after step 501 without any registration process. For example, when the network recovers from an error condition, it can send one or more allowable tracking areas to the UE via a configuration update command message. In step 522, the UE checks that one or more of the allowed tracking areas has a matching TAI in the forbidden TAI list. If the answer is yes, then in step 523, the UE further checks whether the UE is registered for emergency services, with or without any PDU sessions. If the result is yes, the UE does not remove the matching TAI from the prohibited TAI list (step 525), if the result is no, then the UE removes the matching TAI from the prohibited TAI list (step 524).

Figure 6 shows a flowchart of a method for a UE to maintain a list of prohibited TAIs according to a novel aspect. In step 601, the UE maintains a tracking prohibited area identifier (TAI) list in the mobile communication network. The prohibited TAI list includes a list of TAs that prohibit the UE from receiving services from the network. In step 602, the UE receives a service area list from the network, and the service area list includes at least one allowed TAI. In step 603, when the removal condition is met, the UE removes the allowed TAI from the prohibited TAI list. The removal condition includes the UEs prohibition A match of allowed TAI is found in the TAI list. In one embodiment, the service area list is carried by a configuration update command message transmitted from the network. In another embodiment, the service area list is carried by the registration acceptance message from the network in response to the registration request message. If the UE is registered for emergency services, the UE does not remove the allowed TAI from the forbidden TAI list.

Although the present invention has been described in conjunction with certain specific embodiments for illustrative purposes, the present invention is not limited thereto. Therefore, various modifications, adaptations, and combinations can be made to the various features of the described embodiments without departing from the scope of the present invention set forth in the scope of the patent application.