WO2019119343A1

WO2019119343A1 - Cell selection for infrastructure based networks

Info

Publication number: WO2019119343A1
Application number: PCT/CN2017/117702
Authority: WO
Inventors: Miao Fu; Jinghua Fang
Original assignee: Qualcomm Incorporated
Priority date: 2017-12-21
Filing date: 2017-12-21
Publication date: 2019-06-27

Abstract

The disclosure provides a method, UE, and computer-readable medium to facilitate reconnection of a UE to an infrastructure based network such as a high speed train network. The UE may obtain a list of neighbor cells of a serving cell of the UE. The UE may determine based on the list of neighbor cells of the serving cell that the serving cell is a dedicated cell of an infrastructure based network. The UE may save the list of neighbor cells as a list of infrastructure neighbor cells including a plurality of dedicated cells. The UE may add the list of infrastructure neighbor cells to a priority list for cell search in response to determining that a connection to the infrastructure based network has been lost. The UE may connect to one dedicated cell of the plurality of dedicated cells in the list of infrastructure neighbor cells.

Description

CELL SELECTION FOR INFRASTRUCTURE BASED NETWORKS

BACKGROUND

The present disclosure relates generally to wireless communication systems, and more particularly, to dedicated infrastructure based networks such as high speed train (HST) networks.

Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasts. Typical wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources. Examples of such multiple-access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single-carrier frequency division multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems.

These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate on a municipal, national, regional, and even global level. An example telecommunication standard is Long Term Evolution (LTE) . LTE is a set of enhancements to the Universal Mobile Telecommunications System (UMTS) mobile standard promulgated by Third Generation Partnership Project (3GPP) . LTE is designed to support mobile broadband access through improved spectral efficiency, lowered costs, and improved services using OFDMA on the downlink, SC-FDMA on the uplink, and multiple-input multiple-output (MIMO) antenna technology. However, as the demand for mobile broadband access continues to increase, there exists a need for further improvements in LTE technology. These improvements may also be applicable to other multi-access technologies and the telecommunication standards that employ these technologies.

LTE may be deployed alongside other wireless networks such as a Global System for Mobile Communications (GSM) /Enhanced Data rates for GSM Evolution (EDGE) Radio Access Network (GERAN) . For example, GERAN may be used to deploy an infrastructure based network such as a high speed train (HST) network. A user equipment (UE) may be a multi-subscriber identification module (SIM) , multi-standby device, such as a dual-SIM, dual standby (DSDS) device having access to, for example, an LTE network and a GERAN. The DSDS device may share radio frequency hardware by placing one of the networks on standby while performing operations for the other network. A UE that loses a connection with an infrastructure based network may have difficulty reconnecting to the infrastructure based network, which may degrade performance of both a connection to the LTE network and a connection to the GERAN.

SUMMARY

The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects, and is intended to neither identify key or critical elements of all aspects nor delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.

In an aspect, the disclosure provides a method of wireless communication. The method may include obtaining, by a UE, a list of neighbor cells of a serving cell of the UE. The method may include determining based on the list of neighbor cells of the serving cell that the serving cell is a dedicated cell of an infrastructure based network. The method may include saving the list of neighbor cells as a list of infrastructure neighbor cells including a plurality of dedicated cells. The method may include adding the list of infrastructure neighbor cells to a priority list for cell search in response to determining that a connection to the infrastructure based network has been lost. The method may include connecting to one dedicated cell of the plurality of dedicated cells in the list of infrastructure neighbor cells.

In another aspect, the disclosure provides a UE for wireless communication. The UE may include a memory; and at least one processor coupled to the memory. The processor may be configured to obtain a list of neighbor cells of a serving cell of the UE. The processor may be configured to determine based on the list of neighbor cells of the serving cell that the serving cell is a dedicated cell of an infrastructure based network. The processor may be configured to save the list of neighbor cells as a list of infrastructure neighbor cells including a plurality of dedicated cells. The processor may be configured to add the list of infrastructure neighbor cells to a priority list for cell search in response to determining that a connection to the infrastructure based network has been lost. The processor may be configured to connect to one dedicated cell of the plurality of dedicated cells in the list of infrastructure neighbor cells.

In another aspect, the disclosure provides a UE for wireless communication. The UE may include means for obtaining, by the UE, a list of neighbor cells of a serving cell of the UE. The UE may include means for determining based on the list of neighbor cells of the serving cell that the serving cell is a dedicated cell of an infrastructure based network. The UE may include means for saving the list of neighbor cells as a list of infrastructure neighbor cells including a plurality of dedicated cells. The UE may include means for adding the list of infrastructure neighbor cells to a priority list for cell search in response to determining that a connection to the infrastructure based network has been lost. The UE may include means for connecting to one dedicated cell of the plurality of dedicated cells in the list of infrastructure neighbor cells.

In another aspect, the disclosure provides a computer-readable medium storing computer executable code. The computer-readable medium may include code to obtain, by a UE, a list of neighbor cells of a serving cell of the UE. The computer-readable medium may include code to determine based on the list of neighbor cells of the serving cell that the serving cell is a dedicated cell of an infrastructure based network. The computer-readable medium may include code to save the list of neighbor cells as a list of infrastructure neighbor cells including a plurality of dedicated cells. The computer-readable medium may include code to add the list of infrastructure neighbor cells to a priority list for cell search in response to determining that a connection to the infrastructure based network has been lost. The computer-readable medium may include code to connect to one dedicated cell of the plurality of dedicated cells in the list of infrastructure neighbor cells. The computer-readable medium may be a non-transitory computer-readable medium.

To the accomplishment of the foregoing and related ends, the one or more aspects comprise the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative features of the one or more aspects. These features are indicative, however, of but a few of the various ways in which the principles of various aspects may be employed, and this description is intended to include all such aspects and their equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram illustrating an example of a wireless communications system and an access network.

FIG. 2A is a resource diagram illustrating an LTE example of a DL frame structure.

FIG. 2B is a resource diagram illustrating an LTE example of DL channels within the DL frame structure.

FIG. 2C is a resource diagram illustrating an LTE example of an UL frame structure.

FIG. 2D is a resource diagram illustrating an LTE example of UL channels within the UL frame structure.

FIG. 3 is a schematic diagram illustrating an example of an evolved Node B (eNB) and user equipment (UE) in an access network.

FIG. 4 is a schematic diagram of a communication network including a UE that is a DSDS device.

FIG. 5 is a schematic diagram of an example high speed train network.

FIG. 6 is a schematic diagram of example neighbor cells in a high speed train network.

FIG. 7 is a flow diagram showing an example method of operating a UE.

FIG. 8 is a schematic diagram of example components of the UE of FIG. 1.

DETAILED DESCRIPTION

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 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.

A UE that loses a connection with an infrastructure based network may have difficulty reconnecting to the infrastructure based network because the UE may be unaware of which cells are dedicated cells of the infrastructure based network. For example, a GERAN network may have no ability to explicitly indicate whether a cell is a dedicated cell. If the UE connects to a general purpose cell while traveling on a high speed train, the UE may be more likely to lose the connection than if connected to a dedicated cell of the infrastructure based network or may need to change cells. However, because the general purpose cells are unlikely to include dedicated cells on a neighbor list, the UE may not be able to change to a dedicated cell. Attempts by the UE to find and connect to cells of the GERAN network may also limit connectivity of another network (e.g., , an LTE network) in a DSDS device by preempting radio frequency resources.

The present disclosure provides for techniques to reconnect to a dedicated cell of an infrastructure based network. For example, a UE may lose a connection to a dedicated cell due to interference or a radio link failure. Prior to losing the connection, the UE may obtain a neighbor list of a serving cell and determine whether the serving cell is a dedicated cell based on the neighbor list. For example, if the neighbor list has fewer than a threshold number of neighbor cells, the serving cell is likely a dedicated cell. The UE may save the neighbor list and the serving cell as a list of dedicated cells. If the UE loses a connection to the infrastructure based network, the UE may use the saved list of dedicated cells to connect to a dedicated cell of the infrastructure based network. For example, the UE may directly acquire one of the dedicated cells, or if the UE first acquires a general purpose cell, the UE may perform a cell change to one of the dedicated cells. A cell change may include a handover if there is an active call or a cell reselection if the UE is in an idle mode. Accordingly, the UE may quickly return (e.g., without needing to connect to a transfer cell such as at a station) to the dedicated cell of the infrastructure based network to improve performance of both the infrastructure based network and another network on a DSDS device.

Several aspects of telecommunication systems will now be presented with reference to various apparatus and methods. These apparatus and methods will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, components, circuits, processes, algorithms, etc. (collectively referred to as “elements” ) . These elements may be implemented using electronic hardware, computer software, or any combination thereof. Whether such elements are implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system.

By way of example, an element, or any portion of an element, or any combination of elements may be implemented as a “processing system” that includes one or more processors. Examples of processors include microprocessors, microcontrollers, graphics processing units (GPUs) , central processing units (CPUs) , application processors, digital signal processors (DSPs) , reduced instruction set computing (RISC) processors, systems on a chip (SoC) , baseband processors, field programmable gate arrays (FPGAs) , programmable logic devices (PLDs) , state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functionality described throughout this disclosure. One or more processors in the processing system may execute software. Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software components, 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.

Accordingly, in one or more examples, the functions described may be implemented in hardware, software executed by hardware, or any combination thereof. If implemented in software executed by hardware, the functions may be stored on or encoded as one or more instructions or code on a computer-readable medium. Computer-readable media includes computer storage media. Storage media may be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can comprise a random-access memory (RAM) , a read-only memory (ROM) , an electrically erasable programmable ROM (EEPROM) , optical disk storage, magnetic disk storage, other magnetic storage devices, combinations of the aforementioned types of computer-readable media, or any other medium that can be used to store computer executable code in the form of instructions or data structures that can be accessed by a computer.

FIG. 1 is a diagram illustrating an example of a wireless communications system 100 and an access network 105. The wireless communications system 100 (also referred to as a wireless wide area network (WWAN) ) includes base stations 102, UEs 104, and an Evolved Packet Core (EPC) 160. The base stations 102 may include macro cells (high power cellular base station) and/or small cells (low power cellular base station) . The macro cells include eNBs. The small cells may include one or more of femtocells, picocells, and microcells.

The base stations 102 (collectively referred to as Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN) ) interface with the EPC 160 through backhaul links 132 (e.g., S1 interface) . In addition to other functions, the base stations 102 may perform one or more of the following functions: transfer of user data, radio channel ciphering and deciphering, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity) , inter-cell interference coordination, connection setup and release, load balancing, distribution for non-access stratum (NAS) messages, NAS node selection, synchronization, radio access network (RAN) sharing, multimedia broadcast multicast service (MBMS) , subscriber and equipment trace, RAN information management (RIM) , paging, positioning, and delivery of warning messages. The base stations 102 may communicate directly or indirectly (e.g., through the EPC 160) with each other over backhaul links 134 (e.g., X2 interface) . The backhaul links 134 may be wired or wireless.

The base stations 102 may wirelessly communicate with the one or more UEs 104. Each of the base stations 102 may provide communication coverage for a respective geographic coverage area 110. There may be overlapping geographic coverage areas 110. For example, the small cell 102'may have a coverage area 110'that overlaps the geographic coverage area 110 of one or more macro base stations 102. A network that includes both small cell and macro cells may be known as a heterogeneous network. A heterogeneous network may also include Home Evolved Node Bs (eNBs) (HeNBs) , which may provide service to a restricted group known as a closed subscriber group (CSG) . The communication links 120 between the base stations 102 and the UEs 104 may include uplink (UL) (also referred to as reverse link) transmissions from a UE 104 to a base station 102 and/or downlink (DL) (also referred to as forward link) transmissions from a base station 102 to a UE 104. The communication links 120 may use MIMO antenna technology, including spatial multiplexing, beamforming, and/or transmit diversity. The communication links may be through one or more carriers. The base stations 102 /UEs 104 may use spectrum up to Y MHz (e.g., 5, 10, 15, 20 MHz) bandwidth per carrier allocated in a carrier aggregation of up to a total of Yx MHz (x component carriers) used for transmission in each direction. Allocation of carriers may be asymmetric with respect to DL and UL (e.g., more or less carriers may be allocated for DL than for UL) . The component carriers may include a primary component carrier and one or more secondary component carriers. A primary component carrier may be referred to as a primary cell (PCell) and a secondary component carrier may be referred to as a secondary cell (SCell) .

The wireless communications system 100 may include a Wi-Fi access point (AP) 150 in communication with Wi-Fi stations (STAs) 152 via communication links 154 in a 5 GHz unlicensed frequency spectrum. When communicating in an unlicensed frequency spectrum, the STAs 152 /AP 150 may perform a clear channel assessment (CCA) prior to communicating in order to determine whether the channel is available.

The small cell 102'may operate in a licensed and/or an unlicensed frequency spectrum. When operating in an unlicensed frequency spectrum, the small cell 102'may employ LTE and use the same 5 GHz unlicensed frequency spectrum as used by the Wi-Fi AP 150. The small cell 102', employing LTE in an unlicensed frequency spectrum, may boost coverage to and/or increase capacity of the access network. LTE in an unlicensed spectrum may be referred to as LTE-unlicensed (LTE-U) , licensed assisted access (LAA) , or MuLTEfire.

The EPC 160 may include a Mobility Management Entity (MME) 162, other MMEs 164, a Serving Gateway 166, a Multimedia Broadcast Multicast Service (MBMS) Gateway 168, a Broadcast Multicast Service Center (BM-SC) 170, and a Packet Data Network (PDN) Gateway 172. The MME 162 may be in communication with a Home Subscriber Server (HSS) 174. The MME 162 is the control node that processes the signaling between the UEs 104 and the EPC 160. Generally, the MME 162 provides bearer and connection management. All user Internet protocol (IP) packets are transferred through the Serving Gateway 166, which itself is connected to the PDN Gateway 172. The PDN Gateway 172 provides UE IP address allocation as well as other functions. The PDN Gateway 172 and the BM-SC 170 are connected to the IP Services 176. The IP Services 176 may include the Internet, an intranet, an IP Multimedia Subsystem (IMS) , a PS Streaming Service (PSS) , and/or other IP services. The BM-SC 170 may provide functions for MBMS user service provisioning and delivery. The BM-SC 170 may serve as an entry point for content provider MBMS transmission, may be used to authorize and initiate MBMS Bearer Services within a public land mobile network (PLMN) , and may be used to schedule MBMS transmissions. The MBMS Gateway 168 may be used to distribute MBMS traffic to the base stations 102 belonging to a Multicast Broadcast Single Frequency Network (MBSFN) area broadcasting a particular service, and may be responsible for session management (start/stop) and for collecting eMBMS related charging information.

The base station may also be referred to as a Node B, an access point, a base transceiver station, a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS) , an extended service set (ESS) , or some other suitable terminology. The eNB 106 provides an access point to the EPC 160 for a UE 104. Examples of UEs 104 include a cellular phone, a smart phone, a session initiation protocol (SIP) phone, a laptop, a personal digital assistant (PDA) , a satellite radio, a global positioning system, a multimedia device, a video device, a digital audio player (e.g., MP3 player) , a camera, a game console, a tablet, a smart device, a wearable device, or any other similar functioning device. The UE 104 may also be referred to as a station, a mobile station, 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, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other suitable terminology.

Referring again to FIG. 1, in certain aspects, the UE 104 may include a connectivity manager component 430 configured to determine which network (s) and which cells the UE 104 is currently connected to or will connect to. The connectivity manager component 430 may include a tune away component 436 for selecting between networks associated with different subscriptions. For example, the UE 104 may be a DSDS device including multiple SIM cards and the tune away component 436 may select which subscription and associated network the UE 104 will use to communicate. The connectivity manager component 430 may also include a network classification component 440 for determining whether a serving cell of the UE 104 is a dedicated cell of an infrastructure based network or a general purpose cell. The connectivity manager component 430 may also include a neighbor management component 450 for managing various lists of neighbor cells to be used for finding appropriate cells for the UE 104 to acquire or change to. Further details of the connectivity manager component 430 will be discussed below with respect to FIGS. 4 and 8.

FIG. 2A is a diagram 200 illustrating an example of a DL frame structure in LTE. FIG. 2B is a diagram 230 illustrating an example of channels within the DL frame structure in LTE. FIG. 2C is a diagram 250 illustrating an example of an UL frame structure in LTE. FIG. 2D is a diagram 280 illustrating an example of channels within the UL frame structure in LTE. Other wireless communication technologies may have a different frame structure and/or different channels. In LTE, a frame (10 ms) may be divided into 10 equally sized subframes. Each subframe may include two consecutive time slots. A resource grid may be used to represent the two time slots, each time slot including one or more time concurrent resource blocks (RBs) (also referred to as physical RBs (PRBs) ) . The resource grid is divided into multiple resource elements (REs) . In LTE, for a normal cyclic prefix, an RB contains 12 consecutive subcarriers in the frequency domain and 7 consecutive symbols (for DL, OFDM symbols; for UL, SC-FDMA symbols) in the time domain, for a total of 84 REs. For an extended cyclic prefix, an RB contains 12 consecutive subcarriers in the frequency domain and 6 consecutive symbols in the time domain, for a total of 72 REs. The number of bits carried by each RE depends on the modulation scheme.

As illustrated in FIG. 2A, some of the REs carry DL reference (pilot) signals (DL-RS) for channel estimation at the UE. The DL-RS may include cell-specific reference signals (CRS) (also sometimes called common RS) , UE-specific reference signals (UE-RS) , and channel state information reference signals (CSI-RS) . FIG. 2A illustrates CRS for

antenna ports

0, 1, 2, and 3 (indicated as R₀, R₁, R₂, and R₃, respectively) , UE-RS for antenna port 5 (indicated as R₅) , and CSI-RS for antenna port 15 (indicated as R) . FIG. 2B illustrates an example of various channels within a DL subframe of a frame. The physical control format indicator channel (PCFICH) is within symbol 0 of slot 0, and carries a control format indicator (CFI) that indicates whether the physical downlink control channel (PDCCH) occupies 1, 2, or 3 symbols (FIG. 2B illustrates a PDCCH that occupies 3 symbols) . The PDCCH carries downlink control information (DCI) within one or more control channel elements (CCEs) , each CCE including nine RE groups (REGs) , each REG including four consecutive REs in an OFDM symbol. A UE may be configured with a UE-specific enhanced PDCCH (ePDCCH) that also carries DCI. The ePDCCH may have 2, 4, or 8 RB pairs (FIG. 2B shows two RB pairs, each subset including one RB pair) . The physical hybrid automatic repeat request (ARQ) (HARQ) indicator channel (PHICH) is also within symbol 0 of slot 0 and carries the HARQ indicator (HI) that indicates HARQ acknowledgement (ACK) /negative ACK (NACK) feedback based on the physical uplink shared channel (PUSCH) . The primary synchronization channel (PSCH) is within symbol 6 of slot 0 within

subframes

0 and 5 of a frame, and carries a primary synchronization signal (PSS) that is used by a UE to determine subframe timing and a physical layer identity. The secondary synchronization channel (SSCH) is within symbol 5 of slot 0 within

subframes

0 and 5 of a frame, and carries a secondary synchronization signal (SSS) that is used by a UE to determine a physical layer cell identity group number. Based on the physical layer identity and the physical layer cell identity group number, the UE can determine a physical cell identifier (PCI) . Based on the PCI, the UE can determine the locations of the aforementioned DL-RS. The physical broadcast channel (PBCH) is within

symbols

0, 1, 2, 3 of slot 1 of subframe 0 of a frame, and carries a master information block (MIB) . The MIB provides a number of RBs in the DL system bandwidth, a PHICH configuration, and a system frame number (SFN) . The physical downlink shared channel (PDSCH) carries user data, broadcast system information not transmitted through the PBCH such as system information blocks (SIBs) , and paging messages.

As illustrated in FIG. 2C, some of the REs carry demodulation reference signals (DM-RS) for channel estimation at the eNB. The UE may additionally transmit sounding reference signals (SRS) in the last symbol of a subframe. The SRS may have a comb structure, and a UE may transmit SRS on one of the combs. The SRS may be used by an eNB for channel quality estimation to enable frequency-dependent scheduling on the UL. FIG. 2D illustrates an example of various channels within an UL subframe of a frame. A physical random access channel (PRACH) may be within one or more subframes within a frame based on the PRACH configuration. The PRACH may include six consecutive RB pairs within a subframe. The PRACH allows the UE to perform initial system access and achieve UL synchronization. A physical uplink control channel (PUCCH) may be located on edges of the UL system bandwidth. The PUCCH carries uplink control information (UCI) , such as scheduling requests, a channel quality indicator (CQI) , a precoding matrix indicator (PMI) , a rank indicator (RI) , and HARQ ACK/NACK feedback. The PUSCH carries data, and may additionally be used to carry a buffer status report (BSR) , a power headroom report (PHR) , and/or UCI.

FIG. 3 is a block diagram of an eNB 310 in communication with a UE 350 in an access network, such as the access network 105. In the DL, IP packets from the EPC 160 may be provided to a controller/processor 375. The controller/processor 375 implements layer 3 and layer 2 functionality. Layer 3 includes a radio resource control (RRC) layer, and layer 2 includes a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, and a medium access control (MAC) layer. The controller/processor 375 provides RRC layer functionality associated with broadcasting of system information (e.g., MIB, SIBs) , RRC connection control (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release) , inter radio access technology (RAT) mobility, and measurement configuration for UE measurement reporting; PDCP layer functionality associated with header compression /decompression, security (ciphering, deciphering, integrity protection, integrity verification) , and handover support functions; RLC layer functionality associated with the transfer of upper layer packet data units (PDUs) , error correction through ARQ, concatenation, segmentation, and reassembly of RLC service data units (SDUs) , re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto transport blocks (TBs) , demuliplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel prioritization.

The transmit (TX) processor 316 and the receive (RX) processor 370 implement layer 1 functionality associated with various signal processing functions. Layer 1, which includes a physical (PHY) layer, may include error detection on the transport channels, forward error correction (FEC) coding/decoding of the transport channels, interleaving, rate matching, mapping onto physical channels, modulation/demodulation of physical channels, and MIMO antenna processing. The TX processor 316 handles 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) ) . The coded and modulated symbols may then be split into parallel streams. Each stream may then be mapped to an OFDM subcarrier, multiplexed with a reference signal (e.g., pilot) in the time and/or frequency domain, and then combined together using an Inverse Fast Fourier Transform (IFFT) to produce a physical channel carrying a time domain OFDM symbol stream. The OFDM stream is spatially precoded to produce multiple spatial streams. Channel estimates from a channel estimator 374 may be used to determine the coding and modulation scheme, as well as for spatial processing. The channel estimate may be derived from a reference signal and/or channel condition feedback transmitted by the UE 350. Each spatial stream may then be provided to a different antenna 320 via a separate transmitter 318TX. Each transmitter 318TX may modulate an RF carrier with a respective spatial stream for transmission.

At the UE 350, each receiver 354RX receives a signal through a respective antenna 352. Each receiver 354RX recovers information modulated onto an RF carrier and provides the information to the receive (RX) processor 356. The TX processor 368 and the RX processor 356 implement layer 1 functionality associated with various signal processing functions. The RX processor 356 may perform spatial processing on the information to recover any spatial streams destined for the UE 350. If multiple spatial streams are destined for the UE 350, they may be combined by the RX processor 356 into a single OFDM symbol stream. The RX processor 356 then converts the OFDM symbol stream from the time-domain to the frequency domain using a Fast Fourier Transform (FFT) . The frequency domain signal comprises a separate OFDM symbol stream for each subcarrier of the OFDM signal. The symbols on each subcarrier, and the reference signal, are recovered and demodulated by determining the most likely signal constellation points transmitted by the eNB 310. These soft decisions may be based on channel estimates computed by the channel estimator 358. The soft decisions are then decoded and deinterleaved to recover the data and control signals that were originally transmitted by the eNB 310 on the physical channel. The data and control signals are then provided to the controller/processor 359, which implements layer 3 and layer 2 functionality.

The controller/processor 359 can be associated with a memory 360 that stores program codes and data. The memory 360 may be referred to as a computer-readable medium. In the UL, the controller/processor 359 provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, and control signal processing to recover IP packets from the EPC 160. The controller/processor 359 is also responsible for error detection using an ACK and/or NACK protocol to support HARQ operations.

Similar to the functionality described in connection with the DL transmission by the eNB 310, the controller/processor 359 provides RRC layer functionality associated with system information (e.g., MIB, SIBs) acquisition, RRC connections, and measurement reporting; PDCP layer functionality associated with header compression /decompression, and security (ciphering, deciphering, integrity protection, integrity verification) ; RLC layer functionality associated with the transfer of upper layer PDUs, error correction through ARQ, concatenation, segmentation, and reassembly of RLC SDUs, re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto TBs, demuliplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel prioritization.

Channel estimates derived by a channel estimator 358 from a reference signal or feedback transmitted by the eNB 310 may be used by the TX processor 368 to select the appropriate coding and modulation schemes, and to facilitate spatial processing. The spatial streams generated by the TX processor 368 may be provided to different antenna 352 via separate transmitters 354TX. Each transmitter 354TX may modulate an RF carrier with a respective spatial stream for transmission.

The UL transmission is processed at the eNB 310 in a manner similar to that described in connection with the receiver function at the UE 350. Each receiver 318RX receives a signal through a respective antenna 320. Each receiver 318RX recovers information modulated onto an RF carrier and provides the information to a RX processor 370.

The controller/processor 375 can be associated with a memory 376 that stores program codes and data. The memory 376 may be referred to as a computer-readable medium. In the UL, the controller/processor 375 provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, control signal processing to recover IP packets from the UE 350. IP packets from the controller/processor 375 may be provided to the EPC 160. The controller/processor 375 is also responsible for error detection using an ACK and/or NACK protocol to support HARQ operations.

Referring to Fig. 4, in one aspect, the wireless communication system 400 includes a user equipment (UE) 410, which may be an example of the UE 104, for performing a temporary tune back during a tune away mode to maintain an active call. For instance, the UE 410 can communicate with a first base station 102 and/or a second base station 402 utilizing multiple subscriptions to one or more networks. In an example, the UE 410 can have a first subscription 418 related to first network 420 and second subscription 422 related to the same network, or to a different network, such as second network 424. For instance, each subscription 418 and 422 may relate to a different account and/or different services on the same network or on different networks. In some aspects, each subscription 418 and 422 optionally may be maintained on a respective first subscriber identity module (SIM) 426 and a second SIM 428. That is, the first SIM 426 may store information for accessing the first subscription 418 (e.g., for business uses or for making voice calls) and the second SIM 428 may store information for accessing the second subscription 422 (e.g., for personal use or for data services) . As such, in one aspect, the UE 410 may be a multi-SIM, multi-standby device, such as a dual-SIM, dual standby (DSDS) device. Accordingly, the UE 410 can at least communicate in first network 420 via a first base station 102 using first subscription 418. Moreover, the UE 410 can communicate in second network 424 via first base station 102 and/or via a different base station, such as second base station 402, using second subscription 422. Further, first network 420 and second network 424 can use the same or different radio access technologies (RAT) to facilitate communicating with UEs. Additionally, the first base station 102 and the second base station 402 can each be a macrocell, picocell, femtocell, relay, Node B, mobile Node B, UE (e.g., communicating in peer-to-peer or ad-hoc mode with UE 410) , or substantially any type of component that can communicate with UE 410 to provide wireless network access via a subscription at the UE 410. In an example, the first network 420 may be an LTE network such as the wireless communications system 100 and the access network 105. The second network 424 may be a GERAN network, which may include a dedicated infrastructure based network such as a HST network.

The UE 410 can include a modem 470 having a connectivity manager component 430 configured to manage communication exchange signaling associated with the first subscription 418 and/or the second subscription 422 via one or more radio frequency (RF) communication resources 432. For example, the connectivity manager component 430 may include and execute communication protocols and/or manage other standards-specific communication procedures using protocol-and/or standards-specific instructions and/or subscription-specific configuration information that allows communications with the first network 420 and the second network 424. Further, the RF communication resources 432 are configured to transmit and/or receive the communication exchange signaling to and/or from one or more base stations or other devices in the wireless communication system 400. For example, the RF communication resources 432 may include, but are not limited to, one or more of a transmitter, a receiver, a transceiver, protocol stacks, transmit chain components, and receive chain components. In some aspects, the RF communication resources 432 may be dedicated to operate according to the standards and procedures of a single one of first subscription 418 or second subscription 422 at any given time. For instance, although not to be construed as limiting, the RF communication resources 432 may be associated with a multi-SIM, multi-standby device, such as a dual-SIM, dual standby (DSDS) device.

In an aspect, the connectivity manager component 430 may manage multi-network communication to enable mobility of the UE 410, e.g. for a handover, and/or to seek to add to or improve communication quality and/or services. In one case, for example, the connectivity manager component 430 may establish an active call 434 using the first subscription 418 with one network wireless network, for example the first network 420, while attempting to acquire and/or maintain communication and/or service using the second subscription 422 with the same network or with a different network, such as the second network 424. According to an example, the connectivity manager component 430 can establish the active call 434 over the first network 420, related to the first subscription 418, via the first base station 102. For instance, the UE 410 and the base station 102 can establish a connection to facilitate communicating in the first network 420. Communications between the UE 410 and the first base station 102 can occur over logical channels, as described herein for example. The UE 410 can activate the call based on requesting call establishment from base station 102, receiving a page for an incoming call from the base station 102, etc. Moreover, for example, the active call 434 can be a data call (e.g., voice over internet protocol (VoIP) or similar technologies) where the first network 420 is a packet-switched (PS) network, a voice call where the first network 420 is a circuit-switched (CS) network, and/or the like.

Further, the connectivity manager component 430 may also include a tune away component 436 configured to manage switching the RF communication resources 432 from operating on the active call 434 according to the first subscription 418 to operating according to the second subscription 422 to acquire and/or maintain communication and/or service with the same or with a different network. For example, the tune away component 436 may maintain a periodic tune away timer and, upon expiration of the tune away timer, is configured to change operation of the RF communication resources 432 and trigger the connectivity manager component 430 to communicate according to the second subscription 422. The execution of such a tune away, and the subsequent procedures, may be referred to as operating in a tune away mode. For instance, the tune away component 436 causes the RF communication resources 432 to switch or re-initialize an operating state, such as from a first subscription operating state (e.g., for a first network communication or service, like LTE communication) supporting the active call 434 to a second subscription operating state (e.g., for a different first network service or for a different second network communication, like GSM communication) . As such, initiating the tune away mode may include, but is not limited to, one or more operations with respect to the RF communication resources 432, such as performing a wake-up of the second subscription operating state, setting up a corresponding protocol stack for processing signals and data, enabling second subscription-related clocks, RF tuning including changing a receive and/or transmit frequency or frequency range of a transmitter or receiver or transceiver, and any other overhead procedure to enable communication using the second subscription 422. Further, once the second subscription operating state is enabled, the tune away component 436 can be configured to cause the UE 410 and/or connectivity manager component 430 to perform, using the second subscription 422, one or more procedures in the network, such as but not limited to page demodulation, idle mode monitoring procedures, periodic cell/location/routing updates, cell reselections, etc.

In one example, the tune away component 436 initiates tune away mode to communicate with a second network 424 different than the first network 420 supporting active call 434, e.g. the second network 424, via second base station 402. As such, the tune away component 436 enables the RF communication resources 432 to determine whether idle-mode signals are received during the tune away mode from the second base station 402 corresponding to the second network 424. Idle-mode signals can relate to substantially any signal broadcast in the network, e.g. the second network 424, such as paging signals, broadcast control channel (BCCH) signals, or other signals that can correlate to mobility of the UE 410 or otherwise. As such, the tune away component 436 enables the UE 410 to perform at least a first procedure or a first set of procedures, including idle-mode procedures such as page demodulation. Additionally, depending on a state of communications and/or movement of the UE 410 or whether idle-mode signals are received, the tune away component 436 enables device to perform additional procedures, such as but not limited to received signal processing (e.g. determining if a received page relates to the second subscription 422 and optionally responding if so) , periodic cell/location/routing updates, cell reselections, etc. It should be noted that such additional procedures may take a relatively long period of time, such as a period of time longer than an inactivity timer corresponding to the active call 434 of the first subscription 418.

The connectivity manager component 430 may also include a network classification component 440 that determines a classification of a network cell to which the UE 410 is connected. The network cells may be part of a radio access network (RAN) operating using a particular radio access technology (RAT) , but the network operator may divide network cells into different layers for particular purposes. The classification of a network cell may be one of a dedicated network cell and a general purpose network cell. A dedicated network cell may be associated with an infrastructure based network such as a HST network. A general purpose network cell may be any other cell in the RAN. In an aspect, the network classification component 440 may determine the classification of the network cell based on a neighbor list of the network cell. The neighbor list may be configured by a network operator and provided to UEs 410 served by the network cell. A dedicated network cell may have a relatively small number of neighbor cells that are also dedicated network cells. The dedicated network cells may repeat ARFCNs to minimize resources and avoid interference with the general purpose cells. In contrast, the general purpose network cells may have a larger number of neighbor cells (e.g., because the general purpose network cells may have neighbors in multiple directions) . The general purpose cells are also unlikely to have neighbor cells using an ARFCN of known dedicated network cell. Accordingly, the network classification component 440 may use the number of neighbor cells to classify a serving cell as either a dedicated cell or a general purpose cell.

The connectivity manager component 430 may also include a neighbor management component 450 for determining one or more lists of neighbor cells to which the UE 410 may perform a cell change. For example, the neighbor management component 450 may include an HST neighbor cell list 452, a serving cell neighbor cell list 454, and a priority search list 456. Each neighbor cell list may identify a neighbor cell based on AFCRN and cell ID. The HST neighbor cell list 452 may include a plurality of last known dedicated cells. For example, the HST neighbor cell list may include the last dedicated cell to which the UE 410 was connected and the cells on the neighbor list of the last dedicated cell to which the UE 410 was connected. The serving cell neighbor cell list may include a list of neighbor cells of a current serving cell. The priority search list 456 may be a list of priority search targets (e.g., cells or ARFCNs) to search in the event of a lost connection. In an implementation, a single list may include any cell and indicate whether each cell is dedicated cell, a neighbor cell of the serving cell, and/or a priority search target.

FIG. 5 is a schematic diagram of an example infrastructure based network 500. In an aspect, the infrastructure based network 500 may be deployed as a GERAN network, although an infrastructure based network may be deployed in a similar manner using other UMTS radio access technologies. Additionally, the infrastructure based network 500 may be described as a HST network. A HST network may be a network deployed along or near tracks of a high speed train to provide wireless network access to passengers on the high speed train. Due to the high speed of a high speed train, the infrastructure based network 500 may be configured to quickly handover a UE 410 to other cells of the HST network in order to maintain connectivity of the UE 410 to the network and maintain the active call 434. Although the examples herein describe a HST network, an infrastructure based network may be deployed along other types of transportation infrastructure such as highways, tunnels, hyperloops, subways, underground railroads, other railroads, and other forms of transportation where network handovers may be frequent.

The infrastructure based network 500 may be deployed along a high speed train (HST) track 510. The HST track 510 may pass through a plurality of general purpose cells 520. For example, each general purpose cell 520 may be a GERAN macro cell. The general purpose cells 520 may provide a public coverage layer accessible to users within the coverage area of the respective cell who are not necessarily associated with the HST track 510 (e.g., users who are not passengers on the HST) . The infrastructure based network 500 may also include additional base stations 402 that provide a dedicated coverage layer for serving passengers on the HST track 510. The base stations 402 may be deployed in close proximity to the HST track 510. The base stations 402 may provide dedicated cells 530 configured with coverage areas directed toward the HST track 510. Additionally, the dedicated cells 530 may reuse frequency resource (e.g., absolute radio frequency channel numbers (ARFCNs) to conserve resources. In order to avoid co-channel interference, however, a serving cell and its neighbor cells generally do not use the same ARFCN. For example, a UE 410 travelling along the HST track 510 may cycle between ARFCNs as the UE 410 moves between dedicated cells 530, which may prevent interference to the general purpose cells 520. Accordingly, a passenger on the HST track 510 may be within the coverage area of both a general purpose cell 520 and a dedicated cell 530 provided by the base stations 102.

FIG. 6 is a schematic diagram of neighbor cells in the infrastructure based network 500 of FIG. 5. The infrastructure based network 500 may be configured to separate the dedicated coverage layer and the public coverage layer such that users are less likely to transfer between the layers. For example, once a user connects to a dedicated cell 530 of the dedicated coverage layer, the user should remain in the dedicated coverage layer and transfer to another dedicated cell 530 when a cell change occurs. Similarly, a user in a general purpose cell 520 of the public coverage layer should not transition to a dedicated cell 530 of the dedicated coverage layer unless boarding a train. A UE 410 at a train station may be served by a railway station cell 540, which serves as a transition point between the public coverage layer and the dedicated coverage layer. The railway station cell may be a general purpose cell that includes dedicated cells 530 as neighbor cells. The arrows may indicate cells that are likely to be configured on a neighbor list of each cell.

The infrastructure based network 500 may separate the dedicated coverage layer and the public coverage layer by configuring the neighbor cell lists of each cell. Generally, a UE 410 connected to a serving cell may obtain the neighbor cell list from the serving cell and monitor the neighbor cells to determine whether a cell change should occur. By including only cells in the same layer in the neighbor cell list, the UE 410 may be restricted to cell changes to cells within the same layer. For example, the dedicated cell 530-c may include only other dedicated cells 530. For instance, the neighbor list for the dedicated cell 530-c may include overlapping dedicated cells 530-b and 530-c and nearby dedicated cells 530-a and 530-e. Generally, the neighbor list for a dedicated cell may include 6 or fewer cells. As another example, a general purpose cell 520-b may include other general purpose cells 520. For instance, the neighbor list of general purpose cell 520-b may include general purpose cells 520-a, 520-c, 520-d, 520e, as well as railway station cell 540 and other general purpose cells (not shown) that may be located in directions away from the HST track 510.

To facilitate movement between layers where desired, the neighbor lists may include designated transition points where neighbors of the other layer are included. For example, the infrastructure based network 500 may include a railway station cell 540 that covers a geographic area including a train station where users board or debark a train. Accordingly, transitions between layers in both directions may be expected at the railway station cell 540. Accordingly, the neighbor list for the railway station cell 540 may include both general purpose cells 520 and dedicated cells 530. For example, the neighbor list for the railway station cell 540 may include overlapping cells 520-c, 520-d, 520-e, 530-d, and 530-e. The neighbor list for the railway station cell 540 may also include nearby cells such as 520-b, 520-f, 530-c, and 530-f. Accordingly, when leaving the railway station cell 540, a UE may search the neighbor list to determine the strongest cell and change to that cell.

A transition point may also be configured based on natural or man-made features. For example, a signal from a general purpose cell 520 may not be effective in a tunnel 550. Accordingly, a general purpose cell 520-a near the tunnel 550 may include a dedicated cell 530-a in the neighbor list to facilitate movement of a UE 410 from the public coverage layer to the dedicated layer upon entering the tunnel 550. As another example, an canyon 560 (e.g., caused by tall buildings) may provide poor reception of a signal from a general purpose cell 520-f. Accordingly, the neighbor list of the general purpose cell 520-f may include the dedicated cell 530-f.

In an aspect, a UE 410 that loses a connection to a dedicated cell 530 may have difficulty returning to the dedicated network. For example, a UE 410 may not generally be configured to search for the dedicated cells 530 (e.g., because the ARFCNs are not within a usual range for the network) . Also, due to the high speed of the UE 410 on the HST, the UE 410 may exit the coverage area of the previous serving cell before attempting to reconnect to the dedicated network. In some cases, the UE 410 may reconnect to a general purpose cell 520, but may be unable to be handed over to a dedicated cell 530 because the neighbor list of the general purpose cell 520 does not include any dedicated cells 530. The general purpose cell 520, however, may not provide stable service to the UE 410 on the HST track 510. In the case where the UE 410 is a DSDS device, connectivity on the GERAN network may affect service on the other network (e.g., the LTE network) . For example, the UE 410 may execute tune away component 436 to control RF communication resources 432 to perform cell searches and perform signaling on the GERAN network. Accordingly, communications on the LTE network may be interrupted due to unavailability of the RF communication resources 432.

FIG. 7 is a flow diagram showing an example method 700 of operating a UE according to the above-described aspects to reconnect to a dedicated network includes one or more of the herein-defined actions.

At block 710, the method 700 may include obtaining, by a user equipment (UE) , a list of neighbor cells of a serving cell of the UE. In an aspect, for example, the UE 410 may execute RF communication resources 432 to obtain the serving cell neighbor cell list 454 from the serving cell. The serving cell may be, for example, either a general purpose cell 520 or a dedicated cell 530. In the case of a GERAN, the serving cell may not indicate whether the serving cell is a general purpose cell 520 or a dedicated cell 530. The serving cell, however, may broadcast the serving cell neighbor cell list 454, for example as system information on the BCCH. Accordingly, the RF communication resources 432 may obtain the list of neighbor cells of the serving cell by receiving the BCCH.

At block 720, the method 700 may include determining based on the list of neighbor cells of the serving cell that the serving cell of the UE is a dedicated cell of an infrastructure based network. In an aspect, for example, the UE 410 may execute the network classification component 440 to determine whether the serving cell of the UE is a dedicated cell of the infrastructure based network. The determination may be based on the serving cell neighbor cell list 454. The network classification component 440 may determine a signature of the serving cell based on the serving cell neighbor cell list 454. For example, at block 722, block 720 may include determining that a number of neighbor cells is less than or equal to a threshold number of cells. In an aspect, the threshold number of cells is 6, however, the threshold may depend on configuration of a particular infrastructure based network. The threshold number of cells may be configurable by the UE 410 and/or the serving cell. The network classification component 440 may compare a number of cells in the serving cell neighbor cell list 454 to the threshold number of cells. If the number of neighbor cells is less than or equal to the threshold number of cells, the network classification component 440 may determine that the serving cell is a dedicated cell of the infrastructure based network 500. If the number of neighbor cells is greater than the threshold number of cells, the network classification component 440 may determine that the serving cell is a general purpose cell. At block 730, the method 700 may include saving the list of neighbor cells as a list of infrastructure neighbor cells including a plurality of dedicated cells. In an aspect, for example, the neighbor management component 450 may save the serving cell neighbor cell list 454 as the HST neighbor cell list 452. The neighbor management component 450 may save the serving cell neighbor cell list 454 in response to determining that the serving cell of the UE 410 is a dedicated cell 530 of the infrastructure based network 500. The neighbor management component 450 may save the serving cell neighbor cell list 454 while the UE 410 is connected to the serving cell. The neighbor management component 450 may retain the HST neighbor cell list 452 when the UE 410 is handed over to another cell. Accordingly, if the new serving cell is not a dedicate cell 530, the UE 410 may retain the HST neighbor cell list 452 indicating the last known dedicated cells.

At block 740, the method 700 may optionally include adding the serving cell that is the dedicated cell of the infrastructure based network to the list of infrastructure neighbor cells. For example, the neighbor management component 450 may add the serving cell that is the dedicated cell 530 to the HST neighbor cell list 452. Accordingly, although the serving cell is not literally a neighbor cell, the serving cell may be included on the HST neighbor cell list 452 because the network classification component 440 has determined that the serving cell is a dedicated cell 530.

At block 750, the method 700 may include adding the list of infrastructure neighbor cells to a priority list for cell search in response to determining that a connection to the infrastructure based network has been lost. In an aspect, for example, the neighbor management component 450 may add the HST neighbor cell list 452 to the priority search list 456 in response to determining that a connection (e.g., active call 434) to the infrastructure based network 500 has been lost.

At block 760, the method 700 may optionally include acquiring a general purpose cell. In an aspect, for example, the tune away component 436 may control the RF communication resources 432 to acquire a general purpose cell 520. For example, upon detecting that a connection has been lost, the tune away component 436 may acquire a first cell detected, which may be a general purpose cell 520. In an aspect, for example, the tune away component 436 may perform a cell search based on the priority search list 456, which may include known ARFCNs used by the first network 420. Since the UE 410 may not know whether a detected cell is a dedicated cell, the first cell acquired may be a general purpose cell 520.

At block 770, the method 700 may include connecting to one dedicated cell of the plurality of dedicated cells in the list of infrastructure neighbor cells based on the priority list for cell search. In an aspect, for instance, the tune away component 436 may control the RF communication resources 432 to connect to the dedicated cell 530 in the HST neighbor cell list 452. For example, at block 772, the block 770 may include performing initial acquisition of the dedicated cell. For example, the RF communication resources 432 may perform a search for cells in the priority search list 456 and acquire a cell having a suitable signal strength. Since the priority search list 456 was updated in block 750 to include the HST neighbor cell list 452, the acquired cell may be a dedicated cell of the infrastructure based network 500. As another example, at block 774, the block 770 may include performing a cell change from the cell in the general purpose network to the dedicated cell. The block 774 may be performed in response to acquiring the general purpose cell 520 in block 760. The tune away component 436 may control the RF communication resources 432 to determine the relative signal strengths of the neighbor cells on the HST neighbor cell list 452 and/or priority search list 456. Accordingly, the RF communication resources 432 may determine whether the UE 410 can be handed over to a dedicated cell 530, and may perform appropriate signaling to effect the handover if possible. At 776, the block 770 may include tuning away from a first network to connect to the infrastructure network. For example, the tune away component 436 may tune away from the network 424 to connect to the infrastructure based network 500. Since tuning away may reduce performance of the network 424, the tune away component 436 may attempt to quickly connect to the infrastructure based network 500 using the HST neighbor cell list 452.

Referring to FIG. 8 one example of an implementation of UE 104 may include a variety of components, some of which have already been described above, but including components such as one or more processors 812 and memory 816 and transceiver 802 in communication via one or more buses 844, which may operate in conjunction with modem 470 and connectivity manager component 430 to enable one or more of the functions described herein related to connectivity to infrastructure based networks. Further, the one or more processors 812, modem 470, memory 816, transceiver 802, RF front end 888 and one or more antennas 856, may be configured to support voice and/or data calls (simultaneously or non-simultaneously) in one or more radio access technologies. The transceiver 802, RF front end 888 and antennas 856 may be considered RF communication resources 432 and may be used for multiple radio access technologies using the tune away procedures described herein.

In an aspect, the one or more processors 812 can include a modem 470 that uses one or more modem processors. The various functions related to connectivity manager component 430 may be included in modem 470 and/or processors 812 and, in an aspect, can be executed by a single processor, while in other aspects, different ones of the functions may be executed by a combination of two or more different processors. For example, in an aspect, the one or more processors 812 may include any one or any combination of a modem processor, or a baseband processor, or a digital signal processor, or a transmit processor, or a receiver processor, or a transceiver processor associated with transceiver 802. In other aspects, some of the features of the one or more processors 812 and/or modem 470 associated with connectivity manager component 430 may be performed by transceiver 802.

Also, memory 816 may be configured to store data used herein and/or local versions of applications 875 or connectivity manager component 430 and/or one or more of the subcomponents thereof being executed by at least one processor 812. Memory 816 can include any type of computer-readable medium usable by a computer or at least one processor 812, such as random access memory (RAM) , read only memory (ROM) , tapes, magnetic discs, optical discs, volatile memory, non-volatile memory, and any combination thereof. In an aspect, for example, memory 816 may be a non-transitory computer-readable storage medium that stores one or more computer-executable codes defining connectivity manager component 430 and/or one or more of the subcomponents of the connectivity manager component 430, and/or data associated therewith, when UE 104 is operating at least one processor 812 to execute connectivity manager component 430 and/or one or more of the subcomponents of the connectivity manager component 430.

Transceiver 802 may include at least one receiver 806 and at least one transmitter 808. Receiver 806 may include hardware, firmware, and/or software code executable by a processor for receiving data, the code comprising instructions and being stored in a memory (e.g., computer-readable medium) . Receiver 806 may be, for example, a radio frequency (RF) receiver. In an aspect, receiver 806 may receive signals transmitted by at least one base station 102. Additionally, receiver 806 may process such received signals, and also may obtain measurements of the signals, such as, but not limited to, Ec/Io, SNR, RSRP, RSSI, etc. Transmitter 808 may include hardware, firmware, and/or software code executable by a processor for transmitting data, the code comprising instructions and being stored in a memory (e.g., computer-readable medium) . A suitable example of transmitter 808 may including, but is not limited to, an RF transmitter.

Moreover, in an aspect, UE 104 may include RF front end 888, which may operate in communication with one or more antennas 856 and transceiver 802 for receiving and transmitting radio transmissions, for example, wireless communications transmitted by at least one base station 102 or wireless transmissions transmitted by UE 104. RF front end 888 may be connected to one or more antennas 856 and can include one or more low-noise amplifiers (LNAs) 890, one or more switches 892, one or more power amplifiers (PAs) 898, and one or more filters 896 for transmitting and receiving RF signals.

In an aspect, LNA 890 can amplify a received signal at a desired output level. In an aspect, each LNA 890 may have a specified minimum and maximum gain values. In an aspect, RF front end 888 may use one or more switches 892 to select a particular LNA 890 and an associated specified gain value based on a desired gain value for a particular application.

Further, for example, one or more PA (s) 898 may be used by RF front end 888 to amplify a signal for an RF output at a desired output power level. In an aspect, each PA 898 may have specified minimum and maximum gain values. In an aspect, RF front end 888 may use one or more switches 892 to select a particular PA 898 and an associated specified gain value based on a desired gain value for a particular application.

Also, for example, one or more filters 896 can be used by RF front end 888 to filter a received signal to obtain an input RF signal. Similarly, in an aspect, for example, a respective filter 896 can be used to filter an output from a respective PA 898 to produce an output signal for transmission. In an aspect, each filter 896 can be connected to a specific LNA 890 and/or PA 898. In an aspect, RF front end 888 can use one or more switches 892 to select a transmit or receive path using a specified filter 896, LNA 890, and/or PA 898, based on a configuration as specified by transceiver 802 and/or processor 812.

As such, transceiver 802 may be configured to transmit and receive wireless signals through one or more antennas 856 via RF front end 888. In an aspect, transceiver may be tuned to operate at specified frequencies such that UE 104 can communicate with, for example, one or more base stations 102 or one or more cells associated with one or more base stations 102. In an aspect, for example, modem 470 can configure transceiver 802 to operate at a specified frequency and power level based on the UE configuration of the UE 104 and the communication protocol used by modem 470.

In an aspect, modem 470 can be a multiband-multimode modem, which can process digital data and communicate with transceiver 802 such that the digital data is sent and received using transceiver 802. In an aspect, modem 470 can be multiband and be configured to support multiple frequency bands for a specific communications protocol. In an aspect, modem 470 can be multimode and be configured to support multiple operating networks and communications protocols. In an aspect, modem 470 can control one or more components of UE 104 (e.g., RF front end 888, transceiver 802) to enable transmission and/or reception of signals from the network based on a specified modem configuration. In an aspect, the modem configuration can be based on the mode of the modem and the frequency band in use. In another aspect, the modem configuration can be based on UE configuration information associated with UE 104 as provided by the network during cell selection and/or cell reselection.

It is understood that the specific order or hierarchy of blocks in the processes /flowcharts disclosed is an illustration of exemplary approaches. Based upon design preferences, it is understood that the specific order or hierarchy of blocks in the processes /flowcharts may be rearranged. Further, some blocks may be combined or omitted. The accompanying method claims present elements of the various blocks in a sample order, and are not meant to be limited to the specific order or hierarchy presented.

The above detailed description set forth above in connection with the appended drawings describes examples and does not represent the only examples that may be implemented or that are within the scope of the claims. The term “example, ” when used in this description, means “serving as an example, instance, or illustration, ” and not “preferred” or “advantageous over other examples. ” The detailed description includes specific details for the purpose of providing an understanding of the described techniques. These techniques, however, may be practiced without these specific details. In some instances, well-known structures and apparatuses are shown in block diagram form in order to avoid obscuring the concepts of the described examples.

Information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, computer-executable code or instructions stored on a computer-readable medium, or any combination thereof.

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 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. ” The word “exemplary” is used herein to mean “serving as an example, instance, or illustration. ” Any aspect described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects. Unless specifically stated otherwise, the term “some” refers to one or more. Combinations such as “at least one of A, B, or C, ” “one or more of A, B, or C, ” “at least one of A, B, and C, ” “one or more of A, B, and C, ” and “A, B, C, or any combination thereof” include any combination of A, B, and/or C, and may include multiples of A, multiples of B, or multiples of C. Specifically, combinations such as “at least one of A, B, or C, ” “one or more of A, B, or C, ” “at least one of A, B, and C, ” “one or more of A, B, and C, ” and “A, B, C, or any combination thereof” may be A only, B only, C only, A and B, A and C, B and C, or A and B and C, where any such combinations may contain one or more member or members of A, B, or 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. The words “module, ” “mechanism, ” “element, ” “device, ” and the like may not be a substitute for the word “means. ” As such, no claim element is to be construed as a means plus function unless the element is expressly recited using the phrase “means for. ”

Claims

A method of wireless communication, comprising:

obtaining, by a user equipment (UE) , a list of neighbor cells of a serving cell of the UE;

determining based on the list of neighbor cells of the serving cell that the serving cell is a dedicated cell of an infrastructure based network;

saving the list of neighbor cells as a list of infrastructure neighbor cells including a plurality of dedicated cells;

adding the list of infrastructure neighbor cells to a priority list for cell search in response to determining that a connection to the infrastructure based network has been lost; and

selecting and connecting to one dedicated cell of the plurality of dedicated cells in the list of infrastructure neighbor cells.
The method of claim 1, wherein connecting to the one dedicated cell of the plurality of dedicated cells in the list of infrastructure neighbor cells comprises performing initial acquisition of the one dedicated cell.
The method of claim 1, further comprising acquiring a general purpose cell, wherein connecting to the one dedicated cell of the plurality of dedicated cells in the list of infrastructure neighbor cells comprises performing a cell change from the general purpose cell to the one dedicated cell.
The method of claim 3, wherein a neighbor list of the general purpose cell does not include any dedicated cells of the infrastructure based network.
The method of claim 1, wherein determining that the serving cell is the dedicated cell of the infrastructure based network comprises determining that a number of neighbor cells is less than or equal to a threshold number of cells.
The method of claim 5, wherein the threshold number of cells is six.
The method of claim 1, wherein each cell of the list of infrastructure neighbor cells is a dedicated cell of the infrastructure based network.
The method of claim 1, further comprising adding the serving cell that is the dedicated cell of the infrastructure based network to the list of infrastructure neighbor cells.
The method of claim 1, wherein the UE includes at least two subscriber identification module (SIM) cards and connecting to the one dedicated cell comprises tuning away from a first network to the infrastructure based network.
The method of claim 1, wherein the infrastructure based network is a dedicated high speed train (HST) network.
A user equipment (UE) for wireless communication, comprising:

a memory; and

at least one processor coupled to the memory and configured to:

obtain a list of neighbor cells of a serving cell of the UE;

determine based on the list of neighbor cells of the serving cell that the serving cell is a dedicated cell of an infrastructure based network;

save the list of neighbor cells as a list of infrastructure neighbor cells including a plurality of dedicated cells;

add the list of infrastructure neighbor cells to a priority list for cell search in response to determining that a connection to the infrastructure based network has been lost; and

connect to one dedicated cell of the plurality of dedicated cells in the list of infrastructure neighbor cells.
The UE of claim 11, wherein the at least one processor is configured to perform initial acquisition of the one dedicated cell.
The UE of claim 11, wherein the at least one processor is configured to acquire a general purpose cell, and perform a cell change from the general purpose cell to the one dedicated cell.
The UE of claim 13, wherein a neighbor list of the general purpose cell does not include any dedicated cells of the infrastructure based network.
The UE of claim 11, wherein the at least one processor is configured to determine that a number of neighbor cells is less than or equal to a threshold number of cells.
The UE of claim 15, wherein the threshold number of cells is six.
The UE of claim 11, wherein each cell of the list of infrastructure neighbor cells is a dedicated cell of the infrastructure based network.
The UE of claim 11, wherein the at least one processor is configured to add the serving cell that is the dedicated cell of the infrastructure based network to the list of infrastructure neighbor cells.
The UE of claim 11, further comprising at least two subscriber identification module (SIM) cards, wherein the at least one processor is configured to connect to the one dedicated cell by tuning away from a first network to the infrastructure based network.
The UE of claim 11, wherein the infrastructure based network is a dedicated high speed train (HST) network.
A user equipment (UE) for wireless communication, comprising:

means for obtaining, by the UE, a list of neighbor cells of a serving cell of the UE;

means for determining based on the list of neighbor cells of the serving cell that the serving cell is a dedicated cell of an infrastructure based network;

means for saving the list of neighbor cells as a list of infrastructure neighbor cells including a plurality of dedicated cells;

means for adding the list of infrastructure neighbor cells to a priority list for cell search in response to determining that a connection to the infrastructure based network has been lost; and

means for connecting to one dedicated cell of the plurality of dedicated cells in the list of infrastructure neighbor cells.
The UE of claim 21, wherein the means for connecting to the one dedicated cell is configured to perform initial acquisition of the one dedicated cell.
The UE of claim 21, wherein the means for connecting to the one dedicated cell is configured to acquire a general purpose cell and perform a cell change from the general purpose cell to the one dedicated cell.
The UE of claim 21, wherein the means for determining that the serving cell is the dedicated cell of the infrastructure based network is configured to determine that a number of neighbor cells is less than or equal to a threshold number of cells.
The UE of claim 21, further comprising at least two subscriber identification module (SIM) cards, wherein the means for connecting to the one dedicated cell is configured to tune away from a first network to the infrastructure based network.
A computer-readable medium storing computer executable code, comprising code to:

obtain, by a user equipment (UE) , a list of neighbor cells of a serving cell of the UE;

determine based on the list of neighbor cells of the serving cell that the serving cell is a dedicated cell of an infrastructure based network;

save the list of neighbor cells as a list of infrastructure neighbor cells including a plurality of dedicated cells;

add the list of infrastructure neighbor cells to a priority list for cell search in response to determining that a connection to the infrastructure based network has been lost; and

connect to one dedicated cell of the plurality of dedicated cells in the list of infrastructure neighbor cells.
The computer-readable medium of claim 26, wherein the code to determine that the serving cell is the dedicated cell of the infrastructure based network comprises code to determine that a number of neighbor cells is less than or equal to a threshold number of cells.
The computer-readable medium of claim 26, wherein the code to connect to the one dedicated cell of the plurality of dedicated cells in the list of infrastructure neighbor cells comprises code to perform initial acquisition of the one dedicated cell.
The computer-readable medium of claim 26, further comprising code to acquire a general purpose cell, wherein the code to connect to the one dedicated cell of the plurality of dedicated cells in the list of infrastructure neighbor cells comprises code to perform a cell change from the general purpose cell to the one dedicated cell.
The computer-readable medium of claim 29, wherein a neighbor list of the general purpose cell does not include any dedicated cells of the infrastructure based network.