WO2011068557A1

WO2011068557A1 - Method and apparatus for system selection in a wireless multimode terminal

Info

Publication number: WO2011068557A1
Application number: PCT/US2010/029527
Authority: WO
Inventors: Tom Chin; Guangming Shi; Kuo-Chun Lee
Original assignee: Qualcomm Incorporated
Priority date: 2009-12-01
Filing date: 2010-03-31
Publication date: 2011-06-09
Also published as: TW201127118A

Abstract

Wireless multimode user equipment determines its location according to the mobile country code of its most recently registered PLMN ID. If the user equipment determines that it is outside a locale in which a certain wireless radio access technology is exclusive, the user equipment disables that radio access technology and scans for available networks utilizing other radio access technologies. However, if one of the available networks broadcasts a PLMN ID having a mobile country code corresponding to the local wherein the certain wireless radio access technology is exclusive, the user equipment re-enables that radio access technology.

Description

METHOD AND APPARATUS FOR SYSTEM SELECTION IN A WIRELESS

MULTIMODE TERMINAL

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent Application No.

61/265,520, entitled "SYSTEM AND METHOD FOR SYSTEM SELECTION IN A WIRELESS MULTIMODE TERMINAL," filed on December 1, 2009, which is expressly incorporated by reference herein in its entirety.

BACKGROUND

Field

[0002] Aspects of the present disclosure relate generally to wireless communication systems, and more particularly, to the usage of multimode user equipment in international settings.

Background

[0003] Wireless communication networks are widely deployed to provide various communication services such as telephony, video, data, messaging, broadcasts, and so on. Such networks, which are usually multiple access networks, support communications for multiple users by sharing the available network resources. One example of such a network is the Universal Terrestrial Radio Access Network (UTRAN). The UTRAN is the radio access network (RAN) defined as a part of the Universal Mobile Telecommunications System (UMTS), a third generation (3G) mobile phone technology supported by the 3rd Generation Partnership Project (3 GPP). The UMTS, which is the successor to Global System for Mobile Communications (GSM) technologies, currently supports various air interface standards, such as Wideband-Code Division Multiple Access (W-CDMA), Time Division-Code Division Multiple Access (TD-CDMA), and Time Division- Synchronous Code Division Multiple Access (TD-SCDMA). For example, China is pursuing TD-SCDMA as the underlying air interface in the UTRAN architecture with its existing GSM infrastructure as the core network. The UMTS also supports enhanced 3G data communications protocols, such as High Speed Downlink Packet Data (HSDPA), which provides higher data transfer speeds and capacity to associated UMTS networks.

[0004] As the demand for mobile broadband access continues to increase, research and development continue to advance the UMTS technologies not only to meet the growing demand for mobile broadband access, but to advance and enhance the user experience with mobile communications.

SUMMARY

Wireless multimode user equipment determines its location according to the mobile country code of its most recently registered PLMN ID. If the user equipment determines that it is outside a locale in which a certain wireless radio access technology is exclusive, the user equipment disables that radio access technology and scans for available networks utilizing other radio access technologies. However, if one of the available networks broadcasts a Public Land Mobile Network (PLMN) ID having a mobile country code corresponding to the local wherein the certain wireless radio access technology is exclusive, the user equipment re-enables that radio access technology.

[0005] In an aspect of the disclosure, a method used by a multimode user equipment, the multimode user equipment being capable of communicating over a Time Division- Synchronous Code Division Multiple Access Radio Access Technology (TD-SCDMA RAT) that is utilized in a locale, includes determining a location of the multimode user equipment and preventing the multimode user equipment from utilizing the TD- SCDMA RAT when the location is outside the locale.

[0006] In another aspect of the disclosure, an apparatus capable of communicating over a TD-SCDMA RAT that is utilized in a locale includes means for determining a location of a multimode user equipment, and means for preventing the multimode user equipment from utilizing the TD-SCDMA RAT when the location is outside the locale.

[0007] In yet another aspect of the disclosure, a computer program product for use in a multimode user equipment capable of communicating over a TD-SCDMA RAT that is utilized in a locale includes a computer-readable medium comprising code for determining a location of a multimode user equipment, and preventing the multimode user equipment from utilizing the TD-SCDMA RAT when the location is outside the locale.

[0008] In yet another aspect of the disclosure, an apparatus for wireless communication utilizing multimode user equipment capable of communicating over a TD-SCDMA RAT that is utilized in a locale includes at least one processor and a memory coupled to the at least one processor, wherein the at least one processor is configured to determine a location of the multimode user equipment and prevent the multimode user equipment from utilizing the TD-SCDMA RAT when the location is outside the locale.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] FIG. 1 is a block diagram conceptually illustrating an example of a telecommunications system.

[0010] FIG. 2 is a block diagram conceptually illustrating an example of a frame structure in a telecommunications system.

[0011] FIG. 3 is a block diagram conceptually illustrating an example of a NodeB in communication with a UE in a telecommunications system.

[0012] FIG. 4 is a schematic drawing of a PLMN database illustrating an exemplary data structure for storing PLMN information.

[0013] FIG. 5 is a flow chart illustrating an exemplary process according to an aspect of the instant disclosure.

DETAILED DESCRIPTION

[0014] The detailed description set forth below, in connection with the appended drawings, is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of the various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. In some instances, well-known structures and components are shown in block diagram form in order to avoid obscuring such concepts.

[0015] Turning now to FIG. 1, a block diagram is shown illustrating an example of a telecommunications system 100. The various concepts presented throughout this disclosure may be implemented across a broad variety of telecommunication systems, network architectures, and communication standards. By way of example and without limitation, the aspects of the present disclosure illustrated in FIG. 1 are presented with reference to a UMTS system employing a TD-SCDMA standard. In this example, the UMTS system includes a (radio access network) RAN 102 (e.g., UTRAN) that provides various wireless services including telephony, video, data, messaging, broadcasts, and/or other services. The RAN 102 may be divided into a number of Radio Network Subsystems (RNSs) such as an RNS 107, each controlled by a Radio Network Controller (RNC) such as an RNC 106. For clarity, only the RNC 106 and the RNS 107 are shown; however, the RAN 102 may include any number of RNCs and RNSs in addition to the RNC 106 and RNS 107. The RNC 106 is an apparatus responsible for, among other things, assigning, reconfiguring and releasing radio resources within the RNS 107. The RNC 106 may be interconnected to other RNCs (not shown) in the RAN 102 through various types of interfaces such as a direct physical connection, a virtual network, or the like, using any suitable transport network.

The geographic region covered by the RNS 107 may be divided into a number of cells, with a radio transceiver apparatus serving each cell. A radio transceiver apparatus is commonly referred to as a Node B in UMTS applications, but may also be referred to by those skilled in the art as a base station (BS), a base transceiver station (BTS), a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS), an extended service set (ESS), an access point (AP), or some other suitable terminology. For clarity, two Node Bs 108 are shown; however, the RNS 107 may include any number of wireless Node Bs. The Node Bs 108 provide wireless access points to a core network 104 for any number of mobile apparatuses. Examples of a mobile apparatus include a cellular phone, a smart phone, a session initiation protocol (SIP) phone, a laptop, a notebook, a netbook, a smartbook, a personal digital assistant (PDA), a satellite radio, a global positioning system (GPS) device, a multimedia device, a video device, a digital audio player (e.g., MP3 player), a camera, a game console, or any other similar functioning device. The mobile apparatus is commonly referred to as user equipment (UE) in UMTS applications, but may also be referred to by those skilled in the art as a mobile station (MS), a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communications device, a remote device, a mobile subscriber station, an access terminal (AT), a mobile terminal, a wireless terminal, a remote terminal, a handset, a terminal, a user agent, a mobile client, a client, or some other suitable terminology. For illustrative purposes, three UEs 110 are shown in communication with the Node Bs 108. The downlink (DL), also called the forward link, refers to the communication link from a Node B to a UE, and the uplink (UL), also called the reverse link, refers to the communication link from a UE to a Node B.

[0017] The core network 104, as shown, includes a GSM core network. However, as those skilled in the art will recognize, the various concepts presented throughout this disclosure may be implemented in a RAN, or other suitable access network, to provide UEs with access to types of core networks other than GSM networks.

[0018] In this example, the core network 104 supports circuit- switched services with a mobile switching center (MSC) 112 and a gateway MSC (GMSC) 114. One or more RNCs, such as the RNC 106, may be connected to the MSC 112. The MSC 112 is an apparatus that controls call setup, call routing, and UE mobility functions. The MSC 112 also includes a visitor location register (VLR) (not shown) that contains subscriber-related information for the duration that a UE is in the coverage area of the MSC 112. The GMSC 114 provides a gateway through the MSC 112 for the UE to access a circuit-switched network 116. The GMSC 114 includes a home location register (HLR) (not shown) containing subscriber data, such as the data reflecting the details of the services to which a particular user has subscribed. The HLR is also associated with an authentication center (AuC) that contains subscriber-specific authentication data. When a call is received for a particular UE, the GMSC 114 queries the HLR to determine the UE's location and forwards the call to the particular MSC serving that location.

[0019] The core network 104 also supports packet-data services with a serving GPRS support node (SGSN) 118 and a gateway GPRS support node (GGSN) 120. GPRS, which stands for General Packet Radio Service, is designed to provide packet-data services at speeds higher than those available with standard GSM circuit-switched data services. The GGSN 120 provides a connection for the RAN 102 to a packet-based network 122. The packet-based network 122 may be the Internet, a private data network, or some other suitable packet-based network. The primary function of the GGSN 120 is to provide the UEs 110 with packet-based network connectivity. Data packets are transferred between the GGSN 120 and the UEs 110 through the SGSN 118, which performs primarily the same functions in the packet-based domain as the MSC 112 performs in the circuit-switched domain.

[0020] The UMTS air interface is a spread spectrum Direct-Sequence Code Division Multiple Access (DS-CDMA) system. The spread spectrum DS-CDMA spreads user data over a much wider bandwidth through multiplication by a sequence of pseudorandom bits called chips. The TD-SCDMA standard is based on such direct sequence spread spectrum technology and additionally calls for a time division duplexing (TDD), rather than a frequency division duplexing (FDD) as used in many FDD mode UMTS/W-CDMA systems. TDD uses the same carrier frequency for both the UL and DL between a Node B 108 and a UE 110, but divides uplink and downlink transmissions into different time slots in the carrier.

[0021] FIG. 2 shows a frame structure 200 for a TD-SCDMA carrier. The TD-SCDMA carrier, as illustrated, has a frame 202 that is 10 ms in length. The frame 202 has two 5 ms subframes 204, and each of the subframes 204 includes seven time slots, TS0 through TS6. The first time slot, TS0, is usually allocated for downlink communication, while the second time slot, TS1, is usually allocated for uplink communication. The remaining time slots, TS2 through TS6, may be used for either uplink or downlink, which allows for greater flexibility during times of higher data transmission times in either the uplink or downlink directions. A downlink pilot time slot (DwPTS) 206, a guard period (GP) 208, and an uplink pilot time slot (UpPTS) 210 (also known as the uplink pilot channel (UpPCH)) are located between TS0 and TS1. Each time slot, TS0-TS6, may allow data transmission multiplexed on a maximum of 16 code channels. Data transmission on a code channel includes two data portions 212 separated by a midamble 214 and followed by a GP 216. The midamble 214 may be used for features, such as channel estimation, while the GP 216 may be used to avoid inter-burst interference.

[0022] FIG. 3 is a block diagram of a Node B 310 in communication with a UE 350 in a RAN 300, where the RAN 300 may be the RAN 102 in FIG. 1, the Node B 310 may be the Node B 108 in FIG. 1, and the UE 350 may be the UE 110 in FIG. 1. In the downlink communication, a transmit processor 320 may receive data from a data source 312 and control signals from a controller/processor 340. The transmit processor 320 provides various signal processing functions for the data and control signals, as well as reference signals (e.g., pilot signals). For example, the transmit processor 320 may provide cyclic redundancy check (CRC) codes for error detection, coding and interleaving to facilitate forward error correction (FEC), mapping to signal constellations based on various modulation schemes (e.g., binary phase-shift keying (BPSK), quadrature phase-shift keying (QPSK), M-phase-shift keying (M-PSK), M- quadrature amplitude modulation (M-QAM), and the like), spreading with orthogonal variable spreading factors (OVSF), and multiplying with scrambling codes to produce a series of symbols. Channel estimates from a channel processor 344 may be used by a controller/processor 340 to determine the coding, modulation, spreading, and/or scrambling schemes for the transmit processor 320. These channel estimates may be derived from a reference signal transmitted by the UE 350 or from feedback contained in the midamble 214 (FIG. 2) from the UE 350. The symbols generated by the transmit processor 320 are provided to a transmit frame processor 330 to create a frame structure. The transmit frame processor 330 creates this frame structure by multiplexing the symbols with a midamble 214 (FIG. 2) from the controller/processor 340, resulting in a series of frames. The frames are then provided to a transmitter 332, which provides various signal conditioning functions including amplifying, filtering, and modulating the frames onto a carrier for downlink transmission over the wireless medium through smart antennas 334. The smart antennas 334 may be implemented with beam steering bidirectional adaptive antenna arrays or other similar beam technologies.

At the UE 350, a receiver 354 receives the downlink transmission through an antenna 352 and processes the transmission to recover the information modulated onto the carrier. The information recovered by the receiver 354 is provided to a receive frame processor 360, which parses each frame, and provides the midamble 214 (FIG. 2) to a channel processor 394 and the data, control, and reference signals to a receive processor 370. The receive processor 370 then performs the inverse of the processing performed by the transmit processor 320 in the Node B 310. More specifically, the receive processor 370 descrambles and despreads the symbols, and then determines the most likely signal constellation points transmitted by the Node B 310 based on the modulation scheme. These soft decisions may be based on channel estimates computed by the channel processor 394. The soft decisions are then decoded and deinterleaved to recover the data, control, and reference signals. The CRC codes are then checked to determine whether the frames were successfully decoded. The data carried by the successfully decoded frames will then be provided to a data sink 372, which represents applications running in the UE 350 and/or various user interfaces (e.g., display). Control signals carried by successfully decoded frames will be provided to a controller/processor 390. When frames are unsuccessfully decoded by the receiver processor 370, the controller/processor 390 may also use an acknowledgement (ACK) and/or negative acknowledgement (NACK) protocol to support retransmission requests for those frames.

[0024] In the uplink, data from a data source 378 and control signals from the controller/processor 390 are provided to a transmit processor 380. The data source 378 may represent applications running in the UE 350 and various user interfaces (e.g., keyboard). Similar to the functionality described in connection with the downlink transmission by the Node B 310, the transmit processor 380 provides various signal processing functions including CRC codes, coding and interleaving to facilitate FEC, mapping to signal constellations, spreading with OVSFs, and scrambling to produce a series of symbols. Channel estimates, derived by the channel processor 394 from a reference signal transmitted by the Node B 310 or from feedback contained in the midamble transmitted by the Node B 310, may be used to select the appropriate coding, modulation, spreading, and/or scrambling schemes. The symbols produced by the transmit processor 380 will be provided to a transmit frame processor 382 to create a frame structure. The transmit frame processor 382 creates this frame structure by multiplexing the symbols with a midamble 214 (FIG. 2) from the controller/processor 390, resulting in a series of frames. The frames are then provided to a transmitter 356, which provides various signal conditioning functions including amplification, filtering, and modulating the frames onto a carrier for uplink transmission over the wireless medium through the antenna 352.

[0025] The uplink transmission is processed at the Node B 310 in a manner similar to that described in connection with the receiver function at the UE 350. A receiver 335 receives the uplink transmission through the antenna 334 and processes the transmission to recover the information modulated onto the carrier. The information recovered by the receiver 335 is provided to a receive frame processor 336, which parses each frame, and provides the midamble 214 (FIG. 2) to the channel processor 344 and the data, control, and reference signals to a receive processor 338. The receive processor 338 performs the inverse of the processing performed by the transmit processor 380 in the UE 350. The data and control signals carried by the successfully decoded frames may then be provided to a data sink 339 and the controller/processor, respectively. If some of the frames were unsuccessfully decoded by the receive processor, the controller/processor 340 may also use an ACK and/or NACK protocol to support retransmission requests for those frames.

[0026] The controller/processors 340 and 390 may be used to direct the operation at the Node B 310 and the UE 350, respectively. For example, the controller/processors 340 and 390 may provide various functions including timing, peripheral interfaces, voltage regulation, power management, and other control functions. The computer readable media of memories 342 and 392 may store data and software for the Node B 310 and the UE 350, respectively. A scheduler/processor 346 at the Node B 310 may be used to allocate resources to the UEs and schedule downlink and/or uplink transmissions for the UEs.

[0027] A multimode UE 350 utilizing a TD-SCDMA air interface may be enabled to utilize one or more additional RAT modules in addition to TD-SCDMA, such as GSM/GPRS/EDGE, WCDMA, LTE, etc. The multimode UE 350 is especially useful when the handset is used as a world phone that can roam to other countries outside China. That is, the controller/processor 390, the transmit processor 380, the transmit frame processor 382, and/or the transmitter 356; and the receive processor 370, the receive frame processor 360, and/or the receiver 354 may be configured to support a plurality of radio access technologies, including TD-SCDMA and at least one additional radio access technology. Because of the multitude of radio access technologies in existence today and those currently in development, the details relating to the configuration of these and/or other components of a UE 350 to implement the one or more additional radio access technologies are not described herein. However, one having ordinary skill in the art will comprehend that such details are readily available in standards literature, etc., and the scope of the instant disclosure is not limited to any particular additional radio access technology in addition to the TD-SCDMA interface.

[0028] Being capable of interfacing with multiple different networks, a multimode UE 350 typically performs a scan/search to determine what network or networks are available, and selects one of the available networks. The scan/search and select may be triggered at power-up of the UE 350, or upon a loss of coverage. That is, when coverage by a currently selected system is lost, the UE 350 may scan radio signals and select among currently available systems. Further, a scan/search and select may be initiated if the currently acquired system is not the preferred system. For example, if a subscriber to a TD-SCDMA network is currently camped on a WCDMA network, the multimode UE 350 may periodically scan/search for the home network. Alternatively, if a subscriber is currently camped on a network having a low data rate or limited services, the multimode UE 350 may periodically scan/search for a better system, and select the better system when it becomes available.

[0029] Each UMTS network operator is generally identified by a (PLMN) ID, which includes a Mobile Country Code (MCC) and a Mobile Network Code (MNC). The MCC generally includes three digits, and is utilized to uniquely identify the locale of the mobile subscriber. The MNC generally includes two or three digits, and may be utilized to identify a mobile network operator.

[0030] For example, as currently defined, a China Mobile Communications Corporation operator may have an MCC = '460' and MNC = '00;' or MCC = '460' and MNC = '02,' although other identification values may also be utilized, as will be understood by those skilled in the art. The PLMN Identity of the currently acquired system may be obtained by the UE 350 by reading a System Information message, broadcasted by the Node B or base station 310.

[0031] In an aspect of the disclosure, a Universal Subscriber Identity Module (USIM) 470 communicatively coupled to the UE 350 may store information in a PLMN database to facilitate search and system selection. For example, the USIM 470 may interface with the controller/processor 390 of FIG. 3. In another aspect of the disclosure, the PLMN database may be stored in Memory 392. FIG. 4 is a schematic drawing of a PLMN database 400 illustrating an exemplary data structure for storing PLMN information in accordance with an aspect of the instant disclosure.

[0032] The PLMN database 400 may be organized into Elementary Files (EFs), each including one or more PLMN entries 410 in the USIM. For example, the EFs may be categorized to include a "Home PLMN Selector with Access Technology" EF (EFRPLMN_WA_CT) 440, an "Operator controlled PLMN Selector with Access Technology" EF (EF₀PLMN_WACT) 450, and a "User Controlled PLMN Selector with Access Technology" EF (EF_PLMN_WA_CT) 460. Here, EFRPLMN_WA_CT may include the list of home PLMN IDs and the associated radio access technology; EFOPLMN_WACT may include the operator provisioned PLMN IDs and the associated radio access technology; and EF_PLMN_WA_CT may include the user-preferred PLMN IDs and the associated radio access technology. In a further aspect of the disclosure, each of the EFs may be organized in order of priority, according to a preference among available PLMNs in each category.

[0033] As illustrated in FIG. 4, in an aspect of the disclosure, in addition to the MCC and MNC values for each PLMN, each of the PLMN entries 410 may further include a 16- bit Radio Access Technology (RAT) identifier to indicate which RAT is utilized by that particular PLMN. For example, the RAT identifier may be a 16-bit bitmap, wherein individual bits exclusively correspond to a particular RAT, such as GSM, UTRAN, E-UTRAN (i.e., LTE), CDMA lxRTT, CDMA HRPD, etc.

[0034] At any given time, the availability of certain radio access technologies may not be the same in different geographic areas. That is, due to differences in spectrum allocation, legal issues, economic reasons, or essentially any other reason, a particular RAT may be available in certain countries, but not in others. For example, at the current time, TD-SCDMA technology is only deployed in the People's Republic of China. Therefore, when a TD-SCDMA multimode UE roams to other countries, it will not have TD-SCDMA coverage. Under these circumstances, in an aspect of the instant disclosure, the UE implementing a scan/search and select procedure may avoid seeking for TD-SCDMA networks, and only scan/search for an alternate technology.

[0035] In an exemplary process according to an aspect of the instant disclosure, as illustrated in the flow chart of FIG. 5, a multimode UE may carry out an improved scan/search and select process to reduce the time to acquire a new network in essentially any geographic location. In one aspect of the disclosure, the process is executed by the at least one controller/processor 390 in UE 350 as illustrated in FIG. 3. In another aspect of the disclosure, the illustrated process schematically represents a computer program product including a computer readable medium having code for executing the illustrated process steps.

[0036] Referring to FIG. 5, a trigger 510 initiates the system scan/search and select process.

In some aspects, the trigger 510 may include a power-up of the UE, a loss of coverage, or may occur periodically or intermittently in an attempt to change from a currently registered system to a different system, as described above. On the event of the trigger 510, in block 520, the process may access a memory (e.g., the memory 392 of FIG. 3) to determine the MCC of the most recently registered PLMN. That is, the most recently registered PLMN ID may be saved in a non-volatile memory, which is generally accessible at UE power-on as well as during operation of the UE. In another aspect of the disclosure, the PLMN ID may be saved in a volatile memory, which is generally accessible after a loss of coverage or during a periodic scanning for a better PLMN.

[0037] In block 530, the process determines whether the MCC corresponding to the most recently registered PLMN matches a first locale. For example, in an exemplary process according to an aspect of the disclosure, the process determines whether the MCC is equal to '460,' the MCC corresponding to China. If the PLMN does not match the first locale, the process branches to block 540, wherein a first RAT exclusive to the first locale is disabled in the UE. For example, if the MCC is not equal to '460,' the UE may disable the TD-SCDMA RAT (exclusive to China) for future scan/search and select processes, thus, preventing the UE from utilizing the TD-SCDMA RAT. That is, in block 550, the process performs a scan/search for available networks without utilizing the first RAT (in the described example, it is without utilizing TD-SCDMA).

[0038] Within block 550, in a further aspect of the instant disclosure, the scan/search procedure may be made more efficient by skipping entries in the PLMN database that correspond to the first locale. For example, the UE located outside China may skip entries having MCC = '460' in the EFOPLMN_WACT and EF_PLMN_WA_CT categories. That is, during the scan/search procedure, after a PLMN ID is obtained from a System Information Block broadcasted by a Node B or base station, the PLMN ID is compared to entries in the PLMN database in the UE to determine whether the UE may establish a connection with that PLMN. If the obtained PLMN ID matches one stored in the UE, that PLMN may be selected. However, according to an aspect of the disclosure, if the UE is under the assumption that it is outside the first locale based on the decision in block 530, the comparison may skip entries in the PLMN database that correspond to the first locale. In this way the time required to determine which available PLMN to join may be reduced.

[0039] In block 560, the process determines whether the MCC contained in a PLMN ID broadcasted in a System Information Block by a Node B or base station corresponds to the first locale. That is, even though the process determined in block 530 that the most recently registered PLMN did not correspond to the first locale, the UE may have relocated into the first locale in the meantime. In this case, the process branches to block 580, described below, utilizing the RAT that may be exclusive to the first locale. However, if the process determines in block 560 that the MCC received from the Node B or base station does not correspond to the first locale, the process branches to block 570.

[0040] In block 570, the process may select a PLMN according to a correspondence between the PLMN ID received from a Node B or base station, and an entry in the PLMN database in the UE. Here, the process may return to block 550 for one or more iterations, to retrieve a plurality of available PLMNs, or it may return to block 550 if the PLMN ID received from the Node B or base station does not correspond to any entry in the PLMN database. In an aspect of the disclosure, the process may select the first received PLMN if it is the highest priority, e.g., if PLMN ID is the first entry in the PLMN database.

[0041] Returning now to block 530, if the process determines that the most recently registered PLMN corresponds to the first locale, the process branches to block 580, and the RAT exclusive to the first locale is utilized. That is, a scan/search procedure to follow in block 590 may utilize the RAT exclusive to the first locale in addition to one or more RATs in accordance with the capabilities of the multimode UE. The scan/search performed in block 590 is in most respects similar to that described above with reference to block 550; however, the RAT exclusive to the first locale is utilized in addition to the other RAT or RATs.

[0042] Within block 590, in a further aspect of the instant disclosure, the scan/search and select procedure may be made more efficient by skipping entries in the PLMN database that do not correspond to the first locale, since it was determined in block 530 that the most recent MCC corresponds to the first locale and it is then likely that the UE is within the first locale. For example, the UE inside China may skip entries wherein the MCC≠ '460' in the EFOPLMNWACT and EF_PLMNWACT categories (see FIG. 4). That is, during the scan/search procedure, after a PLMN ID is obtained from a System Information Block broadcasted by a Node B or base station, the PLMN ID is compared to entries in the PLMN database in the UE to determine whether the UE may establish a connection with that PLMN. If the obtained PLMN ID matches one stored in the UE, that PLMN may be selected. However, according to an aspect of the disclosure, if the UE is under the assumption that it is inside a certain locale based on the decision in block 530, the comparison may skip entries in the PLMN database that do not correspond to that locale. In this way the time required to determine which available PLMN to join may be reduced.

[0043] In block 595, the process determines whether the MCC contained in a PLMN ID broadcasted in a System Information Block by a Node B or base station corresponds to the first locale. That is, even though the process determined in block 530 that the most recently registered PLMN corresponds to the first locale, the UE may have relocated out of the first locale in the meantime. In this case, the process branches to block 540, described above, not utilizing the RAT that is exclusive to the first locale. However, if the process determines in block 595 that the MCC received from the Node B or base station corresponds to the first locale, the process branches to block 599.

[0044] In block 599, the process may select a PLMN according to a correspondence between the PLMN ID received from a Node B or base station and an entry in the PLMN database in the UE. Here, the process may return to block 590 for one or more iterations, to retrieve a plurality of PLMNs, or it may return to block 590 if the PLMN ID received from the Node B or base station does not correspond to any entry in the PLMN database. In an aspect of the disclosure, the process may select the first received PLMN if it is the highest priority, e.g., if its PLMN ID is the first entry in the PLMN database.

[0045] Several aspects of a telecommunications system have been presented with reference to a TD-SCDMA system. As those skilled in the art will readily appreciate, various aspects described throughout this disclosure may be extended to other telecommunication systems, network architectures and communication standards. By way of example, various aspects may be extended to other UMTS systems such as W- CDMA, High Speed Downlink Packet Access (HSDPA), High Speed Uplink Packet Access (HSUPA), High Speed Packet Access Plus (HSPA+) and TD-CDMA. Various aspects may also be extended to systems employing Long Term Evolution (LTE) (in FDD, TDD, or both modes), LTE-Advanced (LTEA) (in FDD, TDD, or both modes), CDMA2000, Evolution-Data Optimized (EV-DO), Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Ultra-Wideband (UWB), Bluetooth, and/or other suitable systems. The actual telecommunication standard, network architecture, and/or communication standard employed will depend on the specific application and the overall design constraints imposed on the system.

[0046] Several processors have been described in connection with various apparatuses and methods. These processors may be implemented using electronic hardware, computer software, or any combination thereof. Whether such processors are implemented as hardware or software will depend upon the particular application and overall design constraints imposed on the system. By way of example, a processor, any portion of a processor, or any combination of processors presented in this disclosure may be implemented with a microprocessor, microcontroller, digital signal processor (DSP), a field-programmable gate array (FPGA), a programmable logic device (PLD), a state machine, gated logic, discrete hardware circuits, and other suitable processing components configured to perform the various functions described throughout this disclosure. The functionality of a processor, any portion of a processor, or any combination of processors presented in this disclosure may be implemented with software being executed by a microprocessor, microcontroller, DSP, or other suitable platform.

[0047] Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. The software may reside on a computer-readable medium. A computer-readable medium may include, by way of example, memory such as a magnetic storage device (e.g., hard disk, floppy disk, magnetic strip), an optical disk (e.g., compact disc (CD), digital versatile disc (DVD)), a smart card, a flash memory device (e.g., card, stick, key drive), random access memory (RAM), read only memory (ROM), programmable ROM (PROM), erasable PROM (EPROM), electrically erasable PROM (EEPROM), a register, or a removable disk. Although memory is shown separate from the processors in the various aspects presented throughout this disclosure, the memory may be internal to the processors (e.g., cache or register). [0048] Computer-readable media may be embodied in a computer-program product. By way of example, a computer-program product may include a computer-readable medium in packaging materials. Those skilled in the art will recognize how best to implement the described functionality presented throughout this disclosure depending on the particular application and the overall design constraints imposed on the overall system.

[0049] It is to be understood that the specific order or hierarchy of steps in the methods disclosed is an illustration of exemplary processes. Based upon design preferences, it is understood that the specific order or hierarchy of steps in the methods may be rearranged. The accompanying method claims present elements of the various steps in a sample order, and are not meant to be limited to the specific order or hierarchy presented unless specifically recited therein.

[0050] The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein, but is to be accorded the full scope consistent with the language of the claims, wherein reference to an element in the singular is not intended to mean "one and only one" unless specifically so stated, but rather "one or more." Unless specifically stated otherwise, the term "some" refers to one or more. A phrase referring to "at least one of a list of items refers to any combination of those items, including single members. As an example, "at least one of: a, b, or c" is intended to cover: a; b; c; a and b; a and c; b and c; and a, b and c. All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. No claim element is to be construed under the provisions of 35 U.S.C. § 112, sixth paragraph, unless the element is expressly recited using the phrase "means for" or, in the case of a method claim, the element is recited using the phrase "step for."

[0051] What is Claimed is:

Claims

1. A method used by a multimode user equipment, the multimode user equipment being capable of communicating over a TD-SCDMA RAT that is utilized in a locale, the method comprising:

determining a location of the multimode user equipment; and

preventing the multimode user equipment from utilizing the TD-SCDMA RAT when the location is outside the locale.

2. The method of claim 1, wherein the TD-SCDMA RAT is exclusive to the locale.

3. The method of claim 1, further comprising scanning for an available PLMN utilizing a RAT other than the TD-SCDMA RAT.

4. The method of claim 1, wherein the determining the location of the multimode user equipment comprises determining that a PLMN to which the multimode user equipment has most recently registered has a PLMN ID comprising a mobile country code identifying an outside locale other than the locale.

5. The method of claim 4, further comprising comparing a received PLMN ID, received from a Node B, with first entries in a PLMN database accessible by the multimode user equipment, the first entries in the PLMN database consisting of entries that comprise a mobile country code identifying the locale.

6. The method of claim 4, further comprising determining that the location of the multimode user equipment is inside the locale by determining that the received PLMN ID, received from the Node B, comprises a mobile country code identifying the locale.

7. The method of claim 6, further comprising scanning for an available PLMN utilizing at least the TD-SCDMA RAT.

8. The method of claim 1, further comprising scanning for an available PLMN utilizing at least the TD-SCDMA RAT when the location is inside the locale.

9. The method of claim 8, wherein the determining the location of the multimode user equipment comprises determining that a PLMN to which the multimode user equipment has most recently registered has a PLMN ID comprising a mobile country code identifying the locale.

10. The method of claim 9, further comprising comparing a received PLMN ID, received from a NodeB, with first entries in a PLMN database accessible by the multimode user equipment, the first entries in the PLMN database consisting of entries that do not comprise a mobile country code identifying the locale.

11. The method of claim 10, further comprising determining that the location of the multimode user equipment is outside the locale by determining that the received PLMN ID, received from the Node B, comprises a mobile country code identifying an outside locale other than the locale.

12. An apparatus capable of communicating over a TD-SCDMA RAT that is utilized in a locale, comprising:

means for determining a location of a multimode user equipment; and means for preventing the multimode user equipment from utilizing the TD- SCDMA RAT when the location is outside the locale.

13. The apparatus of claim 12, wherein the TD-SCDMA RAT is exclusive to the locale.

14. The apparatus of claim 12, further comprising means for scanning for an available PLMN utilizing a RAT other than the TD-SCDMA RAT.

15. The apparatus of claim 12, wherein the means for determining the location of the multimode user equipment comprises means for determining that a PLMN to which the multimode user equipment has most recently registered has a PLMN ID comprising a mobile country code identifying an outside locale other than the locale.

16. The apparatus of claim 15, further comprising means for comparing a received PLMN ID, received from a Node B, with first entries in a PLMN database accessible by the multimode user equipment, the first entries in the PLMN database consisting of entries that comprise a mobile country code identifying the locale.

17. The apparatus of claim 15, further comprising means for determining that the location of the multimode user equipment is inside the locale by determining that the received PLMN ID, received from the Node B, comprises a mobile country code identifying the locale.

18. The apparatus of claim 17, further comprising means for scanning for an available PLMN utilizing at least the TD-SCDMA RAT.

19. The apparatus of claim 12, further comprising means for scanning for an available PLMN utilizing at least the TD-SCDMA RAT when the location is inside the locale.

20. The apparatus of claim 19, wherein the means for determining the location of the multimode user equipment comprises means for determining that a PLMN to which the multimode user equipment has most recently registered has a PLMN ID comprising a mobile country code identifying the locale.

21. The apparatus of claim 20, further comprising means for comparing a received PLMN ID, received from a Node B, with first entries in a PLMN database accessible by the multimode user equipment, the first entries in the PLMN database consisting of entries that do not comprise a mobile country code identifying the locale.

22. The apparatus of claim 21, further comprising means for determining that the location of the multimode user equipment is outside the locale by determining that the received PLMN ID, received from the NodeB, comprises a mobile country code identifying an outside locale other than the locale.

23. A computer program product for use in a multimode user equipment capable of communicating over a TD-SCDMA RAT that is utilized in a locale, comprising: a computer-readable medium comprising code for:

determining a location of a multimode user equipment; and preventing the multimode user equipment from utilizing the TD- SCDMA RAT when the location is outside the locale.

24. The computer program product of claim 23, wherein the TD-SCDMA RAT is exclusive to the locale.

25. The computer program product of claim 23, wherein the computer-readable medium further comprises code for scanning for an available PLMN utilizing a RAT other than the TD-SCDMA RAT.

26. The computer program product of claim 23, wherein the code for determining the location of the multimode user equipment comprises code for determining that a PLMN to which the multimode user equipment has most recently registered has a PLMN ID comprising a mobile country code identifying an outside locale other than the locale.

27. The computer program product of claim 26, wherein the computer-readable medium further comprises code for comparing a received PLMN ID, received from a Node B, with first entries in a PLMN database accessible by the multimode user equipment, the first entries in the PLMN database consisting of entries that comprise a mobile country code identifying the locale.

28. The computer program product of claim 26, wherein the computer-readable medium further comprises code for determining that the location of the multimode user equipment is inside the locale by determining that the received PLMN ID, received from the NodeB, comprises a mobile country code identifying the locale.

29. The computer program product of claim 28, wherein the computer-readable medium further comprises code for scanning for an available PLMN utilizing at least the TD-SCDMA RAT.

30. The computer program product of claim 23, wherein the computer-readable medium further comprises code for scanning for an available PLMN utilizing at least the TD-SCDMA RAT when the location is inside the locale.

31. The computer program product of claim 30, wherein the code for determining the location of the multimode user equipment comprises code for determining that a PLMN to which the multimode user equipment has most recently registered has a PLMN ID comprising a mobile country code identifying the locale.

32. The computer program product of claim 31, wherein the computer-readable medium further comprises code for comparing a received PLMN ID, received from a Node B, with first entries in a PLMN database accessible by the multimode user equipment, the first entries in the PLMN database consisting of entries that do not comprise a mobile country code identifying the locale.

33. The computer program product of claim 32, wherein the computer-readable medium further comprises code for determining that the location of the multimode user equipment is outside the locale by determining that the received PLMN ID, received from the Node B, comprises a mobile country code identifying an outside locale other than the locale.

34. An apparatus for wireless communication utilizing multimode user equipment capable of communicating over a TD-SCDMA RAT that is utilized in a locale, comprising:

at least one processor; and

a memory coupled to the at least one processor, wherein the at least one processor is configured to:

determine a location of the multimode user equipment; and prevent the multimode user equipment from utilizing the TD-SCDMA RAT when the location is outside the locale.

35. The apparatus of claim 34, wherein the TD-SCDMA RAT is exclusive to the locale.

36. The apparatus of claim 34, wherein the at least one processor is further configured to scan for an available PLMN utilizing a RAT other than the TD- SCDMA RAT.

37. The apparatus of claim 34, wherein the determining the location of the multimode user equipment comprises determining that a PLMN to which the multimode user equipment has most recently registered has a PLMN ID comprising a mobile country code identifying an outside locale other than the locale.

38. The apparatus of claim 37, wherein the at least one processor is further configured to compare a received PLMN ID, received from a Node B, with first entries in a PLMN database accessible by the multimode user equipment, the first entries in the PLMN database consisting of entries that comprise a mobile country code identifying the locale.

39. The apparatus of claim 37, wherein the at least one processor is further configured to determine that the location of the multimode user equipment is inside the locale by determining that the received PLMN ID, received from the Node B, comprises a mobile country code identifying the locale.

40. The apparatus of claim 39, wherein the at least one processor is further configured to scan for an available PLMN utilizing at least the TD-SCDMA RAT.

41. The apparatus of claim 34, wherein the at least one processor is further configured to scan for an available PLMN utilizing at least the TD-SCDMA RAT when the location is inside the locale.

42. The apparatus of claim 41, wherein the determining the location of the multimode user equipment comprises determining that a PLMN to which the multimode user equipment has most recently registered has a PLMN ID comprising a mobile country code identifying the locale.

43. The apparatus of claim 42, wherein the at least one processor is further configured to compare a received PLMN ID, received from a Node B, with first entries in a PLMN database accessible by the multimode user equipment, the first entries in the PLMN database consisting of entries that do not comprise a mobile country code identifying the locale.

44. The apparatus of claim 43, wherein the at least one processor is further configured to determine that the location of the multimode user equipment is outside the locale by determining that the received PLMN ID, received from the Node B, comprises a mobile country code identifying an outside locale other than the locale.