DETERMINATION IN TD-SCDMA MULTIMODE TERMINALS

CROSS-REFERENCE TO RELATED APPLICATION(S)

[0001] This application claims the benefit of U.S. Provisional Patent Application

No. 61/263,132, entitled "METHOD AND APPARATUS FOR UE-BASED POSITION DETERMINATION IN TD-SCDMA MULTIMODE TERMINALS," filed on November 20, 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 methods and apparatus for UE-based position determination in TD-SCDMA multimode terminals.

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.

[0005] Location-based services are popular services being provided to enhance the user experience. However, to provide these services, it is desired that as accurate the location determination is as possible be achieved.

SUMMARY

[0006] In an aspect of the disclosure, a method of wireless communication is provided. The method includes selecting a subset of candidate cells from a plurality of neighboring cells based on a criterion; identifying a reference cell; determining a characteristic associated with propagation times associated with both the reference cell and the subset of candidate cells; and setting a position based on the determined characteristic.

[0007] In an aspect of the disclosure, an apparatus for wireless communication includes means for selecting a subset of candidate cells from a plurality of neighboring cells based on a criterion; means for identifying a reference cell; means for determining a characteristic associated with propagation times associated with both the reference cell and the subset of candidate cells; and means for setting a position based on the determined characteristic.

[0008] In an aspect of the disclosure, a computer program product includes a computer-readable medium including code for selecting a subset of candidate cells from a plurality of neighboring cells based on a criterion; identifying a reference cell; determining a characteristic associated with propagation times associated with both the reference cell and the subset of candidate cells; and setting a position based on the determined characteristic.

[0009] In an aspect of the disclosure, an apparatus for wireless communication includes a processor. The processor is configured to select a subset of candidate cells from a plurality of neighboring cells based on a criterion; identify a reference cell; determine a characteristic associated with propagation times associated with both the reference cell and the subset of candidate cells; and set a position based on the determined characteristic.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] FIG. 1 is a block diagram conceptually illustrating an example of a telecommunications system.

[0011] FIG. 2 is a block diagram conceptually illustrating an example of a frame structure in a telecommunications system.

[0012] FIG. 3 is a block diagram conceptually illustrating an example of a Node B in communication with a UE in a telecommunications system.

[0013] FIG. 4 is a block diagram conceptually illustrating an example of a processing system of the UE of FIG.3.

[0014] FIG. 5 is a diagram of a CDMAlx frame structure as compared to a TD-

SCDMA frame structure illustrating an observed time difference determination.

[0015] FIG. 6 is a flow diagram of a process for determining a UE's position in accordance with an aspect of the present disclosure.

[0016] FIG. 7 is a timing diagram of the process for determining a UE's position in accordance with an aspect of the present disclosure.

[0017] FIG. 8 is a conceptual block diagram illustrating the functionality of an exemplary UE apparatus.

DETAILED DESCRIPTION

[0018] 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.

[0019] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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 uplink (UL) and downlink (DL) between a Node B 108 and a UE 110, but divides uplink and downlink transmissions into different time slots in the carrier.

[0025] 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, TSO through TS6. The first time slot, TSO, 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 TSO 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 guard period (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.

[0026] 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 202 in FIG. 2, the Node B 310 may be the Node B 208 in FIG. 2, and the UE 350 may be the UE 210 in FIG. 2. 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 the one or more smart antenna 334. The one or more smart antenna 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 one or more antennas 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.

[0028] 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 one or more antenna 352.

[0029] 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 one or more 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.

[0030] 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.

[0031] FIG. 4 is a block diagram illustrating a configuration for an apparatus 400, which can be a UE 110. The apparatus 400 may include a wireless interface 402, a processing system 404, and machine-readable media 406. The wireless interface 402 may be integrated into the processing system 404 or distributed across multiple entities in the apparatus. The processing system 404 may be implemented with one or more processors. The one or more processors may be implemented with any combination of general-purpose microprocessors, microcontrollers, digital signal processors (DSPs), digital signal processing devices (DSPDs), field programmable gate array (FPGAs), programmable logic devices (PLDs), controllers, integrated circuits (ICs), application specific ICs (ASICs), state machines, gated logic, discrete hardware components, or any other suitable entities that can perform calculations or other manipulations of information.

[0032] The processing system 404 is coupled to machine-readable media 406 for storing software. Alternatively, the processing system 404 may itself include the machine-readable media 406. Software shall be construed broadly to mean any type of instructions, whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. Instructions may include code (e.g., in source code format, binary code format, executable code format, or any other suitable format of code). The instructions, when executed by the one or more processors, cause the processing system 404 to perform the various functions described below, as well as various protocol processing functions.

[0033] When the embodiments are implemented in software, firmware, middleware or microcode, program code or code segments, they can be stored in a machine- readable medium, such as a storage component. A code segment can represent a procedure, a function, a subprogram, a program, a routine, a subroutine, a module, a software package, a class, or any combination of instructions, data structures, or program statements. A code segment can be coupled to another code segment or a hardware circuit by passing and/or receiving information, data, arguments, parameters, or memory contents. Information, arguments, parameters, and/or data can be passed, forwarded, or transmitted using any suitable means including memory sharing, message passing, token passing, and network transmission.

[0034] For a software implementation, the techniques described herein can be implemented with modules (e.g., procedures, functions, and so on) that perform the functions described herein. The software codes can be stored in memory units and executed by processors. The memory unit can be implemented within the processor or external to the processor, in which case it can be communicatively coupled to the processor via various means as is known in the art.

[0035] The TD-SCDMA standards provide position determination for UEs without the use of GPS receivers using three schemes:

[0036] 1. Cell ID: Use the current cell to approximate the UE's position.

[0037] 2. UE-assisted Observed Time Difference of Arrival (OTDOA): The UE measures the difference in time of arrival of several cells and signals the measurement results to the network, where the network carries out the position calculation. The OTDOA uses the SFN-SFN (System Frame Number-to-System Frame Number) observed time difference between the neighbor cell and the reference cell.

[0038] 3. UE-based OTDOA: The UE measures the difference in time of arrival of several cells and also carries out the position calculation. Finally, the UE signals the positioning results to the network.

[0039] To perform UE-based OTDOA, the TD-SCDMA standards specify that the

Node B (NB) broadcasts the position information of the serving cell and the neighbor cells in the system information message. In particular, the system information block type 15.5 (SIB- 15.5) includes the OTDOA assistance data for UE-based Information Elements (IE). This IE indicates the position information for the serving cell and neighbor cells. Specifically, the latitude and longitude information for the reference cell is included. In the UE positioning OTDOA neighbor cell info for UE-based IE, the relative position to the reference cell is given for a neighbor cell.

[0040] However, UE-based positioning may require at least three base station measurements in addition to a reference base station. Specifically, an observed time difference between each of three base stations and the reference base station is needed. Because the UE may not be able to receive valid signal from a sufficient number of base stations in the TD-SCDMA network, in one aspect of the disclosure a multimode TD-SCDMA UE can utilize the CDMA lx network to improve signal detection and perform other measurements for UE position calculation.

[0041] When there are not enough base stations in the TD-SCDMA network with good signal quality, UE position may be estimated using the observed time difference of base stations in the CDMA lx BS as well as the base stations in the TD-SCDMA network.

[0042] A system requirement of the 3 GPP and 3GPP2 standards is that TD-SCDMA and CDMA lx systems are synchronous. Specifically, TD-SCDMA frames, which are 10-ms in length, and CDMA frames, which are 20-ms in length, are aligned. These frames are also aligned with GPS time. In CDMA lx system, the location of the serving base station (BS) is indicated in the System Parameters Message (SPM).

[0043] In one aspect of the disclosure, UE location estimation is supported by the search and measurements of a CDMA lx network in addition to the TD-SCDMA network for a multimode terminal. Thus, a multimode (TD-SCDMA and CDMA lx) terminal may search for CDMA lx base station signals as well as TD-SCDMA base station signals to improve the availability and accuracy of the UE positioning process.

[0044] Referring to FIG. 6, and further referring to FIG. 7, an UE position determination process 600 will be described where, in step 602, cells (base stations) within range of a UE 702, referred to as neighboring cells such as cells710, 712, 720 and 722, are chosen for inclusion in a group of candidate base stations. In one aspect of the disclosure, a signal to interference plus noise ratio is chosen as the metric to select preferred candidate base stations such that:

[0045] · Candidate TD-SCDMA NB may be determined by measuring Signal-to-

Interference Ratio (SIR) of the Primary Common Control Physical Channel (P- CCPCH), denoted by S_td(i) in dB. Assume that index i reference each available TD- SCDMA NB with an available signal measurement.

[0046] · Candidate CDMA lx base station may be determined by measuring its pilot

Signal-to-Interference and Noise Ratio (SINR), denoted by S_cd(j) in dB. Assume that index j reference each available CDMA BS with an available signal measurement.

[0047] Therefore, the multimode terminal can choose the best M base stations, where

M > 4, among the TD-SCDMA and CDMA lx networks for the UE-based positioning determination process.

[0048] To adjust for different network technologies, the following adjustments are used in the selecting base stations:

[0049] · TD-SCDMA NB: S_td(i) - Offset td

[0050] · CDMA lx BS: S_cd(j) - Offset cd

[0051] The above offset or adjustment values, Offset td, Offset cd (in dB), are constant for a particular Radio Access Technology (RAT).

[0052] In step 604, in one aspect of the disclosure, the strongest TD-SCDMA Node B from the candidate cells in the above signal measurement procedure will be chosen as a reference cell, identified as TD reference cell 710.

[0053] In step 606, the UE measures the time difference from each neighbor cell (TD-

SCDMA or CDMA, such as TD neighbor cell 712, CDMAlx neighbor cell B 720, and CDMAlx neighbor cell C 722) to the reference cell, TD reference cell 710. The observed time difference in TD-SCDMA network is defined as a System Frame Number (SFN-SFN) observed time difference. That is, the UE 702 can measure the delay in received frame boundary of the neighbor cell relative to the reference cell. The SFN-SFN observed time difference is defined as the arrival time difference of a frame boundary of a TD-SCDMA/CDMA lx neighbor cell relative to the reference cell. The SFN-SFN observed time difference is positive if the frame boundary of the neighbor cell is detected to be received later than the frame boundary of the reference cell.

[0054] The observed time difference for CDMA lx relative to TD-SCDMA reference cell 710 may be measured similarly, except that there are two TD-SCDMA frames per CDMA frame and therefore the closest TD-SCDMA frame boundary is used. FIG. 5 includes a frame timing diagram 500 that illustrates the concept of determining a difference between a CDMA lx frame boundary and a TD-SCDMA frame boundary. The time difference measurement is performed on at least three neighbor base station (TD-SDMA NB or CDMA BS), such as TD neighbor cell A 712, CDMAlx cell B 720 and CDMAlx neighbor cell C 722 relative the TD-SCDMA reference cell 710 in the above procedure.

[0055] In step 608, the UE 702 acquires the positions of the TD-SCDMA reference cell 710 and neighbor cells such as the TD neighbor cell A 712 in the TD-SCDMA network from SIB-15.5. For CDMA lx neighbor cells, such as CDMAlx neighbor cell B 720 and CDMAlx neighbor cell C 722, the UE 702 needs to acquire the SPM for each of these neighbor cells.

[0056] In step 610, the UE 702 utilizes the observed time difference and the location of these base stations to estimate the UE location.

[0057] FIG. 8 is a functional block diagram 800 illustrating example blocks executed in conducting wireless communication according to one aspect of the present disclosure. Block 802 includes selecting a subset of candidate cells from a plurality of neighboring cells based on a criterion. In addition, block 804 includes identifying a reference cell. Furthermore, block 806 includes determining a characteristic associated with propagation times associated with both the reference cell and the subset of candidate cells. Moreover, block 808 includes setting a position based on the determined characteristic.

[0058] In one configuration, the apparatus 350 for wireless communication includes means for selecting a subset of candidate cells from a plurality of neighboring cells based on a criterion; means for identifying a reference cell; means for determining a characteristic associated with propagation times associated with both the reference cell and the subset of candidate cells; and means for setting a position based on the determined characteristic. In one aspect, the aforementioned means may be the processor 390 configured to perform the functions recited by the aforementioned means. In another aspect, the aforementioned means may be a module or any apparatus configured to perform the functions recited by the aforementioned means.

[0059] 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 (LTE-A) (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.

[0060] 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.

[0061] 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).

[0062] 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.

[0063] 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.

[0064] 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."

What is claimed is: