WO2017101048A1 - Réglage de temporisation durant une procédure de canal d'accès aléatoire - Google Patents

Réglage de temporisation durant une procédure de canal d'accès aléatoire Download PDF

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Publication number
WO2017101048A1
WO2017101048A1 PCT/CN2015/097618 CN2015097618W WO2017101048A1 WO 2017101048 A1 WO2017101048 A1 WO 2017101048A1 CN 2015097618 W CN2015097618 W CN 2015097618W WO 2017101048 A1 WO2017101048 A1 WO 2017101048A1
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WIPO (PCT)
Prior art keywords
contention
command
rach procedure
procedure
timer
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PCT/CN2015/097618
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English (en)
Inventor
Haiqin LIU
Bao Vinh Nguyen
Peng Wu
Xiaochen Chen
Congchong Ru
Deepak KRISHNAMOORTHI
Gang Xiao
Vasanth Kumar RAMKUMAR
Shailesh Maheshwari
Tom Chin
Anjali BANSAL
Rajarajan RAJENDRAN
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Qualcomm Incorporated
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Priority to PCT/CN2015/097618 priority Critical patent/WO2017101048A1/fr
Publication of WO2017101048A1 publication Critical patent/WO2017101048A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W56/00—Synchronisation arrangements
    • H04W56/004—Synchronisation arrangements compensating for timing error of reception due to propagation delay
    • H04W56/0045—Synchronisation arrangements compensating for timing error of reception due to propagation delay compensating for timing error by altering transmission time
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W74/00—Wireless channel access
    • H04W74/08—Non-scheduled access, e.g. ALOHA
    • H04W74/0833—Random access procedures, e.g. with 4-step access

Definitions

  • the present disclosure relates generally to communication systems, and more particularly, to maintenance of uplink time alignment.
  • 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.
  • CDMA code division multiple access
  • TDMA time division multiple access
  • FDMA frequency division multiple access
  • OFDMA orthogonal frequency division multiple access
  • SC-FDMA single-carrier frequency division multiple access
  • TD-SCDMA time division synchronous code division multiple access
  • LTE Long Term Evolution
  • UMTS Universal Mobile Telecommunications System
  • 3GPP Third Generation Partnership Project
  • 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.
  • MIMO multiple-input multiple-output
  • Timing advance is used to control the uplink timing of individual user equipment (UE) by ensuring that transmissions from all UEs associated with a base station are synchronized when reaching the base station.
  • the UE that is the furthest from the base station may have a larger TA to compensate for the larger propagation delay of uplink transmission.
  • Each UE has a configurable TA timer to control how long the UE is considered uplink time aligned.
  • the term handover or handoff refers to the process of transferring an ongoing call or data session from one channel connected to the core network to another channel.
  • a random access channel (RACH) procedure occurs.
  • RACH random access channel
  • a contention based RACH procedure the same RACH preamble from multiple UEs may reach the network at the same time. As a result, the network may go through additional contention resolution process to resolve these contentions.
  • the TA timer may be set to run due to a received TA command before the contention is successfully resolved. If the contention resolution fails, the TA timer may continue to run to indicate that the UE is uplink time aligned while the UE is actually out of synchronization. As long as the TA timer is running, the UE is prevented from getting uplink time aligned through a TA command carried in a Random Access Response message.
  • a UE When a UE receives a TA command including a relative TA value, the relative TA value is applied to the UE and the TA timer of the UE starts to run immediately.
  • the UE is considered to be in synchronization (i.e., uplink time aligned) .
  • the Random Access Response message received by the UE from the base station may carry a TA value that is an absolute TA value.
  • the TA value received in the Random Access Response message is ignored, thus preventing the UE from becoming uplink time aligned through the absolute TA value received in the Random Access Response message. This may detrimentally affect the UE’s performance if the initial contention resolution fails and the UE’s TA value is set to a fixed value or a previous value, which may not achieve uplink time alignment for the UE.
  • a method, a computer-readable medium, and an apparatus for wireless communication are provided.
  • the apparatus may be a base station.
  • the apparatus may perform a contention-based RACH procedure with a UE.
  • the apparatus may receive a reconfiguration complete message from the UE in connection with the contention-based RACH procedure.
  • the apparatus may send a TA command to the UE.
  • the apparatus may refrain from sending timing advance information prior to receiving the reconfiguration complete message.
  • a method, a computer-readable medium, and an apparatus for wireless communication are provided.
  • the apparatus may be a UE.
  • the apparatus may receive a TA command in connection with a contention-based RACH procedure.
  • the apparatus may start a TA timer.
  • the TA timer defines an interval during which subsequent TA commands received in connection with the contention-based RACH procedure are disregarded.
  • the apparatus may detect an out-of-sync condition during the interval.
  • the apparatus may stop the TA timer when the out-of-sync condition is detected.
  • an out-of-sync condition may be detected during the contention-based RACH procedure and the UE may stop its TA timer.
  • the out-of-sync condition may be detected when the UE travels at a speed that exceeds a threshold speed while performing the contention-based RACH procedure.
  • the out-of-sync condition may alternatively be detected if a predetermined number of RACH failures have occurred with the contention-based RACH procedure or if a timing drift of downlink signals exceeds a predetermined threshold.
  • the UE may perform a subsequent pass of the contention-based RACH procedure. During the subsequent RACH attempt, the UE may receive a second TA command and may send an UL signal based on the second TA command.
  • 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.
  • FIG. 1 is a diagram illustrating an example of a wireless communications system and an access network.
  • FIGS. 2A, 2B, 2C, and 2D are diagrams illustrating LTE examples of a DL frame structure, DL channels within the DL frame structure, an UL frame structure, and UL channels within the UL frame structure, respectively.
  • FIG. 3 is a diagram illustrating an example of an evolved Node B (eNB) and user equipment (UE) in an access network.
  • eNB evolved Node B
  • UE user equipment
  • FIG. 4 is a diagram illustrating aspects of a contention based RACH procedure performed by a base station.
  • FIG. 5 is a diagram illustrating aspects of a contention based RACH procedure performed by a UE.
  • FIG. 6 is a flowchart of a method of a contention based RACH procedure performed by a base station.
  • FIG. 7 is a flowchart of a method of a contention based RACH procedure performed by a UE.
  • FIG. 8 is a data flow diagram illustrating the data flow between different means/components in an exemplary apparatus.
  • FIG. 9 is a diagram illustrating an example of a hardware implementation for an apparatus employing a processing system.
  • FIG. 10 is a data flow diagram illustrating the data flow between different means/components in an exemplary apparatus.
  • FIG. 11 is a diagram illustrating an example of a hardware implementation for an apparatus employing a processing system.
  • 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.
  • 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.
  • the functions described may be implemented in hardware, software, or any combination thereof. If implemented in software, 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.
  • 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.
  • RAM random-access memory
  • ROM read-only memory
  • EEPROM electrically erasable programmable ROM
  • optical disk storage magnetic 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 and an access network 100.
  • the wireless communications system also referred to as a wireless wide area network (WWAN)
  • WWAN wireless wide area network
  • 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 include 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) .
  • UMTS Universal Mobile Telecommunications System
  • E-UTRAN Evolved Universal Mobile Telecommunications System Terrestrial Radio Access Network
  • 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 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 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) .
  • eNBs Home Evolved Node Bs
  • HeNBs Home Evolved Node Bs
  • CSG closed subscriber group
  • 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.
  • the carriers may or may not be adjacent to each other. 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 may further 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.
  • AP Wi-Fi access point
  • STAs Wi-Fi stations
  • communication links 154 in a 5 GHz 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.
  • CCA clear channel assessment
  • the small cell 102' may operate in a licensed and/or 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.
  • MME Mobility Management Entity
  • MBMS Multimedia Broadcast Multicast Service
  • BM-SC Broadcast Multicast Service Center
  • PDN Packet Data Network
  • the MME 162 may be in communication with a Home Subscriber Server (HSS) 174.
  • HSS Home Subscriber Server
  • the MME 162 is the control node that processes the signaling between the UEs 104 and the EPC 160.
  • 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.
  • IP Internet protocol
  • 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.
  • PLMN public land mobile network
  • 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.
  • MMSFN Multicast Broadcast Single Frequency Network
  • the base station may also be referred to as a Node B, evolved Node B (eNB) , 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 base station 102 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.
  • SIP session initiation protocol
  • PDA personal digital assistant
  • 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.
  • the UE 104 /eNB 102 may be configured to perform (at 198) timing adjustment during a contention-based RACH procedure.
  • UE 104 and eNB 102 may be configured to identify when an out-of-sync condition may arise in connection with a contention-based RACH procedure and to manage the use of TA information to avoid RACH failure. Details of the operations performed at 198 are described below with reference to FIGS. 4-11.
  • 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.
  • 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) .
  • REs resource elements
  • 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.
  • 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.
  • 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) .
  • CRS cell-specific reference signals
  • UE-RS UE-specific reference signals
  • CSI-RS channel state information reference signals
  • FIG. 2A illustrates CRS for antenna ports 0, 1, 2, and 3 (indicated as R 0 , R 1 , R 2 , and R 3 , respectively) , UE-RS for antenna port 5 (indicated as R 5 ) , 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.
  • DCI downlink control information
  • CCEs control channel elements
  • 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.
  • 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.
  • PSS primary synchronization signal
  • the secondary synchronization channel 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.
  • SIBs system information blocks
  • 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.
  • SRS sounding reference signals
  • 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.
  • PRACH physical random access channel
  • the PRACH allows the UE to perform initial system access and achieve UL synchronization.
  • a physical uplink control channel 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.
  • UCI uplink control information
  • the PUSCH carries data, and may additionally be used to carry a buffer status report (BSR) , a power headroom report (PHR) , and/or UCI.
  • BSR buffer status report
  • PHR power headroom report
  • FIG. 3 is a block diagram of an eNB 310 in communication with a UE 350 in an access network.
  • 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
  • layer 2 includes a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, and a medium access control (MAC) layer.
  • RRC radio resource control
  • PDCP packet data convergence protocol
  • RLC radio link control
  • MAC medium access control
  • 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 S
  • 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) ) .
  • BPSK binary phase-shift keying
  • QPSK quadrature phase-shift keying
  • M-PSK M-phase-shift keying
  • M-QAM M-quadrature amplitude modulation
  • 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.
  • IFFT Inverse Fast Fourier Transform
  • 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.
  • TA information may be transmitted by the TX processor 316 on the DL to a UE
  • each receiver 354RX receives a signal through its 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) .
  • FFT Fast Fourier Transform
  • 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.
  • 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.
  • 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.
  • RRC layer functionality associated with system information (e.g., MIB, SIBs) acquisition, RRC connections, and measurement reporting
  • PDCP layer functionality associated
  • TA information may be received by the RX processor 356 on the DL and used to time-align UL signals.
  • the TX processor 368 (or the controller/processor 359) may respond to TA commands and tracks UL synchronization.
  • 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 its respective antenna 320.
  • Each receiver 318RX recovers information modulated onto an RF carrier and provides the information to a RX processor 370.
  • the eNB 310 may perform a contention-based RACH procedure using a transmitter 318TX and a receiver 318RX with a UE.
  • the eNB may transmit one or more TA commands to the UE to time-align the UL signals from the UE.
  • 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.
  • 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. Components described above with reference to FIG. 3 may support call flow and implementations of the algorithms described below.
  • a UE e.g., 104 may get a TA command from a base station (e.g., 102) before contention resolution.
  • the contention based RACH procedure may be a contention based handover RACH procedure.
  • the UE may apply the TA value included in the TA command, and start the TA timer to indicate that the UE is in synchronization (i.e., uplink time aligned) .
  • a fixed TA value may be applied (e.g., TA value 39 for TDD and TA value 0 for FDD) .
  • the TA value of the UE may be tuned back to a previous value after sending the RACH preamble in the RACH procedure.
  • the UE may be out-of-sync at physical layer.
  • the UE may receive a second absolute TA value in the Random Access Response message of the second RACH attempt.
  • the second absolute TA value may not be applied to the physical layer of the UE.
  • TA values received through subsequent Random Access Response messages may continue to be ignored until the TA timer expires or the RACH attempt is aborted by radio resource control (RRC) .
  • RRC radio resource control
  • the RACH attempt may fail.
  • the scenario described above is more likely to happen when the UE moves at high speed (e.g., traveling in a high speed train) .
  • FIG. 4 is a diagram 400 illustrating aspects of a contention based RACH procedure performed by a base station.
  • a UE 402 initiates a contention based RACH procedure with a base station 404.
  • the contention-based RACH procedure may be used in connection with handover of the UE 402.
  • the UE 402 may be the UE 104 or 350 described above with reference to FIG 1 or 3, respectively.
  • the base station 404 may be the base station 102 or the eNB 310 described above with reference to FIG 1 or 3, respectively.
  • the UE 402 may send (at 410) a RACH preamble to the base station 404.
  • the base station 404 may send (at 412) a Random Access Response message back to the UE 402.
  • the UE 402 may send (at 414) a RRC connection request message to the base station 404.
  • the base station 404 may send (at 416) a contention resolution message back to the UE 402.
  • the UE 402 may decode RRC connection setup message and send (at 418) a RRC reconfiguration complete message to the base station 404 to indicate the successful completion of the contention based RACH procedure.
  • the contention resolution message may not be received by the UE 402 until a second, third, or more RACH attempt.
  • the base station 404 supplies TA information after a certain point in the RACH procedure to make sure that there is alignment between the TA value used by the UE 402 and the TA value commanded by the network.
  • a misalignment can result when the UE 402 starts its TA timer and the base station 404 sends a subsequent TA command.
  • the base station 404 tries to manage this by refraining (at 430) from sending TA values until the UE has completed enough of the RACH procedures that it will not need to make another pass.
  • the base station 404 may refrain (at 430) from sending TA command to the UE 402 before the base station 404 receives the RRC reconfiguration complete message from the UE 402.
  • the base station 404 may not transmit any TA command to the UE 402 during the time period 432, which is from the reception of the RACH preamble to the reception of the RRC reconfiguration complete message.
  • the base station 404 may send (at 420) a TA command to the UE 402.
  • the TA command may be sent with a MAC layer control element which may include a Cell Radio Network Temporary Identifier (C-RNTI) assigned to the UE during the RACH procedure.
  • C-RNTI Cell Radio Network Temporary Identifier
  • the base station 404 avoids starting the TA timer of the UE 402 before the contention based RACH procedure is successfully completed. Otherwise, if the initial contention based RACH attempt fails, no subsequent TA commands may be accepted by the UE 402 while its TA timer is running. As a result, the TA timer of the UE 402 may block subsequent TA commands leading to a misalignment between UE 402 and based station 404 and, ultimately, to RACH failure.
  • FIG. 5 is a diagram 500 illustrating aspects of a contention based RACH procedure performed by a UE.
  • a UE 502 initiates a contention based RACH procedure with a base station 504, e.g., in connection with a handover by sending (at 510) a RACH preamble to the base station 504.
  • the UE 502 may be the UE 104 or 350 described above with reference to FIG 1 or 3, respectively.
  • the base station 504 may be the base station 102 or the eNB 310 described above with reference to FIG 1 or 3, respectively.
  • the base station 504 may send (at 512) a TA command to the UE 502 before contention resolution (e.g., before potentially sending a contention resolution message to the UE 502 at 516) .
  • the UE 502 may start a TA timer.
  • the TA command may include a relative TA value and the UE 502 may adjust its uplink transmissions based on relative TA value.
  • the TA command may be received with a C-RNTI for UE 502.
  • the UE 502 may stop (at 532) the TA timer that is started by the TA command if the UE 502 detects an out-of-sync condition.
  • the out-of-sync condition may be detected if the UE 502 travels at a speed that exceeds a threshold speed while performing the contention-based RACH procedure.
  • the traveling speed of the UE 502 may be measured by a sensor (e.g., an accelerometer) of the UE 502.
  • the out-of-sync condition may alternatively be detected if a predetermined number of RACH failures have occurred with the contention-based RACH procedure.
  • the predetermined number of RACH failures may be one, two, three or more.
  • the out-of-sync condition may alternatively be detected if a timing drift of downlink signals exceeds a predetermined threshold.
  • the above mentioned methods for detecting the out-of-sync condition may be performed independently, or two or more of these methods may be performed jointly.
  • the UE 502 By terminating the TA timer started by the TA command when an out-of-sync condition is detected, the UE 502 prevents the TA timer from continuously running even if the contention resolution has failed. As a result, the UE 502 may be able to be configured with a correct TA value by applying a TA value received in a Random Access Response message of a subsequent RACH attempt.
  • FIG. 6 is a flowchart 600 of a method of wireless communication. Specifically, the flowchart 600 illustrates a method of a contention based RACH procedure.
  • the contention based RACH may be used in connection with a handover of a UE.
  • the method may be performed by an eNB (e.g., the base station 102, 404, the eNB 310, or the apparatus 802/802') .
  • the operations described in this method may be the operations described above with reference to FIG. 4.
  • the eNB performs a contention-based RACH procedure with a UE (e.g., the UE 402) .
  • the eNB may perform the contention based RACH procedure by sending Random Access Response message and contention resolution message to the UE, or receiving RACH preamble and RRC connection request message from the UE.
  • the eNB receives a reconfiguration complete message from the UE in connection with the contention-based RACH procedure.
  • the reconfiguration complete message may include a radio resource control (RRC) message.
  • RRC radio resource control
  • the eNB sends a TA command to the UE in response to the reconfiguration complete message.
  • the eNB may be configured to refrain from sending timing advance information prior to receiving the reconfiguration complete message.
  • the TA command may be included with a MAC control element. In such aspect, the TA command may include a relative TA value.
  • FIG. 7 is a flowchart 700 of a method of wireless communication. Specifically, the flowchart 700 illustrates a method of a contention based RACH procedure. The method may be performed by a UE (e.g., the UE 104, 350, 502, or the apparatus 1002/1002’ ) .
  • the contention based RACH procedure may be used in connection with a handover of the UE.
  • the operations described in this method may be the operations described above with reference to FIG. 5.
  • the UE receives a TA command in connection with a contention-based RACH procedure (e.g., from the base station 504) .
  • the TA command may be included with a MAC control element.
  • the TA command may include a relative adjustment to the timing of uplink signals sent by the UE (e.g., relative TA value) .
  • the UE may apply the relative TA value contained in the TA command.
  • the UE applies the relative TA value by setting the TA of the UE to be the relative TA value.
  • the TA command may be received with a temporary identifier (e.g., C-RNTI) assigned to the UE.
  • the UE starts a TA timer in response to receiving the TA command.
  • the running of the TA timer may indicate that the UE is uplink time aligned.
  • the TA timer may define an interval during which subsequent TA commands received in connection with the contention-based RACH procedure are disregarded.
  • the UE determines whether an out-of-sync condition exists for uplink timing.
  • the out-of-sync condition may be detected if the UE travels at a speed that exceeds a threshold speed while performing the contention-based RACH procedure.
  • the traveling speed of the UE may be measured by a sensor (e.g., an accelerometer) of the UE.
  • the out-of-sync condition may alternatively be detected if a predetermined number of RACH failures have occurred with the contention-based RACH procedure.
  • the predetermined number of RACH failures may be one, two, three or more.
  • the out-of-sync condition may alternatively be detected if a timing drift of downlink signals exceeds a predetermined threshold.
  • the above mentioned methods for detecting the out-of-sync condition may be performed independently, or two or more of these methods may be performed jointly.
  • the UE proceeds to 708. If the out-of-sync condition is not detected, the UE proceeds to 710.
  • the UE stops the TA timer.
  • the UE may stop the TA timer by disabling the TA timer.
  • the UE may optionally perform a subsequent pass of the contention-based RACH procedure.
  • the UE may optionally receive a second TA command during the subsequent pass of the contention-based handover RACH procedure.
  • the second TA command may be received with the Random Access Response message.
  • the second TA command may include an absolute TA value.
  • the UE may optionally send an uplink signal based on the second TA command.
  • the TA value included in the second TA command enables the UE to be uplink time aligned.
  • the UE may send the uplink signal based on the aligned uplink timing enabled by the second TA command.
  • the UE may prevent the TA timer from continuously running even if the uplink timing of the UE is out-of-sync. As a result, the UE may be able to be configured with a correct TA value by applying the TA value received in the second TA command during the subsequent pass of the contention-based RACH procedure.
  • FIG. 8 is a data flow diagram 800 illustrating the data flow between different means/components in an exemplary apparatus 802.
  • the apparatus 802 may be an eNB (e.g., the base station 404) .
  • the apparatus 802 includes a reception component 804 that receives RACH related messages (e.g., RACH preamble, RRC connection request message, etc. ) from a UE 850.
  • RACH related messages e.g., RACH preamble, RRC connection request message, etc.
  • the UE 850 may be the UE 402 described above with reference to FIG. 4.
  • the reception component 804 may perform operations described above with reference to 602 or 604 of FIG. 6.
  • the apparatus 802 includes a transmission component 810 that sends RACH related messages (e.g., Random Access Response message, contention resolution message, etc. ) and TA command to the UE 850.
  • RACH related messages e.g., Random Access Response message, contention resolution message, etc.
  • TA command e.g., TA command to the UE 850.
  • the transmission component 810 may perform operations described above with reference to 602 or 606 of FIG. 6.
  • the reception component 804 and the transmission component 810 may work together to coordinate the communication of the apparatus 802.
  • the apparatus 802 may include a RACH component 806 that performs the contention based RACH procedure.
  • the RACH component 806 may receive some RACH related messages from the reception component 804 and send some RACH related messages to the transmission component 810.
  • the RACH component 806 may perform operations described above with reference to 602 of FIG. 6.
  • the apparatus 802 may include a TA command component 808 that receives RACH status from the RACH component 806 and determines to send a TA command to the transmission component 810 only when the RACH status indicates that the contention based RACH procedure is completed.
  • the contention based RACH procedure may be completed when the apparatus 802 receives a RRC reconfiguration complete message from the UE 850.
  • the TA command component 808 may perform operations described above with reference to 606 of FIG. 6.
  • the transmission component 810 may send the TA command with C-RNTI.
  • the apparatus may include additional components that perform each of the blocks of the algorithm in the aforementioned flowchart of FIG. 6. As such, each block in the aforementioned flowchart of FIG. 6 may be performed by a component and the apparatus 802 may include one or more of those components.
  • the components may be one or more hardware components specifically configured to carry out the stated processes/algorithm, implemented by a processor configured to perform the stated processes/algorithm, stored within a computer-readable medium for implementation by a processor, or some combination thereof.
  • FIG. 9 is a diagram 900 illustrating an example of a hardware implementation for an apparatus 802'employing a processing system 914.
  • the apparatus 802’ may be the apparatus 802 described above with reference to FIG. 8.
  • the processing system 914 may be implemented with a bus architecture, represented generally by the bus 924.
  • the bus 924 may include any number of interconnecting buses and bridges depending on the specific application of the processing system 914 and the overall design constraints.
  • the bus 924 links together various circuits including one or more processors and/or hardware components, represented by the processor 904, the components 804, 806, 808, 810, and the computer-readable medium /memory 906.
  • the bus 924 may also link various other circuits such as timing sources, peripherals, voltage regulators, and power management circuits, which are well known in the art, and therefore, will not be described any further.
  • the processing system 914 may be coupled to a transceiver 910.
  • the transceiver 910 is coupled to one or more antennas 920.
  • the transceiver 910 provides a means for communicating with various other apparatus over a transmission medium.
  • the transceiver 910 receives a signal from the one or more antennas 920, extracts information from the received signal, and provides the extracted information to the processing system 914, specifically the reception component 804.
  • the transceiver 910 receives information from the processing system 914, specifically the transmission component 810, and based on the received information, generates a signal to be applied to the one or more antennas 920.
  • the processing system 914 includes a processor 904 coupled to a computer-readable medium /memory 906.
  • the processor 904 is responsible for general processing, including the execution of software stored on the computer-readable medium /memory 906.
  • the software when executed by the processor 904, causes the processing system 914 to perform the various functions described supra for any particular apparatus.
  • the computer-readable medium /memory 906 may also be used for storing data that is manipulated by the processor 904 when executing software.
  • the processing system 914 further includes at least one of the components 804, 806, 808, 810.
  • the components may be software components running in the processor 904, resident/stored in the computer readable medium /memory 906, one or more hardware components coupled to the processor 904, or some combination thereof.
  • the processing system 914 may be a component of the eNB 310 and may include the memory 376 and/or at least one of the TX processor 316, the RX processor 370, and the controller/processor 375.
  • the apparatus 802/802’ may include means for performing a contention-based RACH procedure with a UE.
  • the means for performing a contention-based RACH procedure with a UE may perform operations described above with reference to 602 of FIG. 6.
  • the means for performing a contention-based RACH procedure with a UE may be the RACH component 806 or the processor 904.
  • the apparatus 802/802'for wireless communication includes means for receiving a reconfiguration complete message from the UE in connection with the contention-based RACH procedure.
  • the means for receiving a reconfiguration complete message from the UE in connection with the contention-based RACH procedure may perform operations described above with reference to 604 of FIG. 6.
  • the means for receiving a reconfiguration complete message from the UE in connection with the contention-based RACH procedure may be the transceiver 910, the one or more antennas 920, the reception component 804, or the processor 904.
  • the apparatus 802/802’ may include means for sending a TA command to the UE in response to the reconfiguration complete message.
  • the means for sending a TA command to the UE in response to the reconfiguration complete message may perform operations described above with reference to 606 of FIG. 6.
  • the means for sending a TA command to the UE in response to the reconfiguration complete message may be the transceiver 910, the one or more antennas 920, the transmission component 810, the TA command component 808, or the processor 904.
  • the apparatus 802/802’ may include means for refraining from sending timing advance information prior to receiving the reconfiguration complete message.
  • the means for refraining from sending timing advance information prior to receiving the reconfiguration complete message may perform operations described above with reference to 606 of FIG. 6.
  • the means for refraining from sending timing advance information prior to receiving the reconfiguration complete message may be the TA command component 808 or the processor 904.
  • the aforementioned means may be one or more of the aforementioned components of the apparatus 802 and/or the processing system 914 of the apparatus 802'configured to perform the functions recited by the aforementioned means.
  • the processing system 914 may include the TX Processor 316, the RX Processor 370, and the controller/processor 375.
  • the aforementioned means may be the TX Processor 316, the RX Processor 370, and the controller/processor 375 configured to perform the functions recited by the aforementioned means.
  • FIG. 10 is a data flow diagram 1000 illustrating the data flow between different means/components in an exemplary apparatus 1002.
  • the apparatus may be a UE (e.g., the UE 502 or 602) .
  • the apparatus includes a reception component 1004 that receives RACH related messages (e.g., Random Access Response message, contention resolution message, etc. ) and TA command from a base station 1050 (e.g., the base station 504) .
  • RACH related messages e.g., Random Access Response message, contention resolution message, etc.
  • TA command from a base station 1050 (e.g., the base station 504) .
  • the reception component 1004 may perform operations described above with reference to 702 or 712 of FIG. 7.
  • the reception component 1004 may receive the TA command with C-RNTI.
  • the apparatus 1002 includes a transmission component 1010 that sends RACH related messages (e.g., RACH preamble, RRC connection request message, etc. ) and other uplink signals to the base station 1050.
  • RACH related messages e.g., RACH preamble, RRC connection request message, etc.
  • the transmission component 1010 may perform operations described above with reference to 714 of FIG. 7.
  • the reception component 1004 and the transmission component 1010 may work together to coordinate the communication of the apparatus 1002.
  • the apparatus 1002 may include a RACH component 1006 that performs the contention based RACH procedure.
  • the RACH component 1006 may receive some RACH related messages from the reception component 1004 and send some RACH related messages to the transmission component 1010.
  • the RACH component 1006 may perform operations described above with reference to 710 of FIG. 7.
  • the apparatus 1002 may include a TA management component 1008 that receives TA command from the reception component 1004.
  • the TA management component 1008 may apply the TA value contained in the TA command to the apparatus 1002 and start/stop a TA timer of the apparatus 1002.
  • the TA management component 1008 may perform operations described above with reference to 704 or 708 of FIG. 7.
  • the apparatus 1002 may include an out-of-sync detection component 1012 that detects out-of-sync condition of the apparatus 1002 based on contention resolution status received from the RACH component 1006 and/or other information.
  • the out-of-sync detection component 1012 may send a timer termination command to the TA management component 1008 to stop the TA timer.
  • the out-of-sync detection component 1012 may perform operations described above with reference to 706 of FIG. 7.
  • the apparatus may include additional components that perform each of the blocks of the algorithm in the aforementioned flowchart of FIG. 7. As such, each block in the aforementioned flowchart of FIG. 7 may be performed by a component and the apparatus may include one or more of those components.
  • the components may be one or more hardware components specifically configured to carry out the stated processes/algorithm, implemented by a processor configured to perform the stated processes/algorithm, stored within a computer-readable medium for implementation by a processor, or some combination thereof.
  • FIG. 11 is a diagram 1100 illustrating an example of a hardware implementation for an apparatus 1002'employing a processing system 1114.
  • the apparatus 1002’ may be the apparatus 1002 described above with reference to FIG. 10.
  • the processing system 1114 may be implemented with a bus architecture, represented generally by the bus 1124.
  • the bus 1124 may include any number of interconnecting buses and bridges depending on the specific application of the processing system 1114 and the overall design constraints.
  • the bus 1124 links together various circuits including one or more processors and/or hardware components, represented by the processor 1104, the components 1004, 1006, 1008, 1010, 1012, and the computer-readable medium /memory 1106.
  • the bus 1124 may also link various other circuits such as timing sources, peripherals, voltage regulators, and power management circuits, which are well known in the art, and therefore, will not be described any further.
  • the processing system 1114 may be coupled to a transceiver 1110.
  • the transceiver 1110 is coupled to one or more antennas 1120.
  • the transceiver 1110 provides a means for communicating with various other apparatus over a transmission medium.
  • the transceiver 1110 receives a signal from the one or more antennas 1120, extracts information from the received signal, and provides the extracted information to the processing system 1114, specifically the reception component 1004.
  • the transceiver 1110 receives information from the processing system 1114, specifically the transmission component 1010, and based on the received information, generates a signal to be applied to the one or more antennas 1120.
  • the processing system 1114 includes a processor 1104 coupled to a computer-readable medium /memory 1106.
  • the processor 1104 is responsible for general processing, including the execution of software stored on the computer-readable medium /memory 1106.
  • the software when executed by the processor 1104, causes the processing system 1114 to perform the various functions described supra for any particular apparatus.
  • the computer-readable medium /memory 1106 may also be used for storing data that is manipulated by the processor 1104 when executing software.
  • the processing system 1114 further includes at least one of the components 1004, 1006, 1008, 1010, and 1012.
  • the components may be software components running in the processor 1104, resident/stored in the computer readable medium /memory 1106, one or more hardware components coupled to the processor 1104, or some combination thereof.
  • the processing system 1114 may be a component of the UE 350 and may include the memory 360 and/or at least one of the TX processor 368, the RX processor 356, and the controller/processor 359.
  • the apparatus 1002/1002'for wireless communication includes means for receiving a TA command in connection with a contention-based RACH procedure.
  • the means for receiving a TA command in connection with a contention-based RACH procedure may perform operations described above with reference to 702 of FIG. 7.
  • the means for receiving a TA command in connection with a contention-based RACH procedure may be the transceiver 1110, the one or more antennas 1120, the reception component 1004, or the processor 1104.
  • the apparatus 1002/1002' may include means for starting a TA timer in response to receiving the TA command.
  • the means for starting a TA timer in response to receiving the TA command may perform operations described above with reference to 704 of FIG. 7.
  • the means for starting a TA timer in response to receiving the TA command may be the TA management component 1008 or the processor 1104.
  • the apparatus 1002/1002' may include means for detecting an out-of-sync condition.
  • the means for detecting an out-of-sync condition may perform operations described above with reference to 706 of FIG. 7.
  • the means for detecting an out-of-sync condition may be the out-of-sync detection component 1012 or the processor 1104.
  • the means for detecting the out-of-sync condition may be configured to determine that the UE exceeds a threshold speed while performing the contention-based RACH procedure. In one aspect, the means for detecting the out-of-sync condition may be configured to detect that a predetermined number of RACH failures has occurred with the contention-based RACH procedure. In one aspect, the means for detecting the out-of-sync condition is configured to detect that a timing drift of downlink signals exceeds a predetermined threshold.
  • the apparatus 1002/1002' may include means for stopping the TA timer when the out-of-sync condition is detected.
  • the means for stopping the TA timer when the out-of-sync condition is detected may perform operations described above with reference to 708 of FIG. 7.
  • the means for stopping the TA timer when the out-of-sync condition is detected may be the TA management component 1008 or the processor 1104.
  • the apparatus 1002/1002' may include means for performing a subsequent pass of the contention-based RACH procedure.
  • the means for performing a subsequent pass of the contention-based RACH procedure may perform operations described above with reference to 710 of FIG. 7.
  • the means for performing a subsequent pass of the contention-based RACH procedure may be the RACH component 1006 or the processor 1104.
  • the apparatus 1002/1002' may include means for receiving a second TA command during the subsequent pass of the contention-based RACH procedure.
  • the means for receiving a second TA command during the subsequent pass of the contention-based RACH procedure may perform operations described above with reference to 712 of FIG. 7.
  • the means for receiving a second TA command during the subsequent pass of the contention-based RACH procedure may be the transceiver 1110, the one or more antennas 1120, the reception component 1004, or the processor 1104.
  • the apparatus 1002/1002' may include means for sending an UL signal based on the second TA command.
  • the means for sending an UL signal based on the second TA command may perform operations described above with reference to 714 of FIG. 7.
  • the means for sending an UL signal based on the second TA command may be the transceiver 1110, the one or more antennas 1120, the transmission component 1010, or the processor 1104.
  • the aforementioned means may be one or more of the aforementioned components of the apparatus 1002 and/or the processing system 1114 of the apparatus 1002'configured to perform the functions recited by the aforementioned means.
  • the processing system 1114 may include the TX Processor 368, the RX Processor 356, and the controller/processor 359.
  • the aforementioned means may be the TX Processor 368, the RX Processor 356, and the controller/processor 359 configured to perform the functions recited by the aforementioned means.
  • 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.
  • 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.

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Abstract

Selon un aspect de l'invention, un équipement utilisateur (UE) peut recevoir une instruction de réglage de temporisation (TA) en liaison avec une procédure RACH basée sur une contention. En réponse à la réception de l'instruction de TA, l'UE peut démarrer un temporisateur de TA. Le temporisateur de TA définit un intervalle durant lequel des instructions de TA ultérieures reçues en liaison avec la procédure RACH basée sur une contention sont ignorées. L'UE peut détecter une condition hors synchronisation durant l'intervalle. L'UE peut arrêter le temporisateur de TA si la condition hors synchronisation est détectée. Selon un autre aspect, un nœud B évolué (eNB) peut réaliser une procédure RACH basée sur une contention avec un UE. L'eNB peut recevoir un message d'achèvement de reconfiguration à partir de l'UE en liaison avec la procédure RACH basée sur une contention. En réponse au message d'achèvement de reconfiguration, l'eNB peut envoyer une instruction de TA à l'UE. L'eNB peut s'abstenir d'envoyer des informations de TA avant la réception du message d'achèvement de reconfiguration.
PCT/CN2015/097618 2015-12-16 2015-12-16 Réglage de temporisation durant une procédure de canal d'accès aléatoire WO2017101048A1 (fr)

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CN111886917A (zh) * 2018-04-04 2020-11-03 华为技术有限公司 随机接入方法及装置
WO2021040738A1 (fr) * 2019-08-29 2021-03-04 Qualcomm Incorporated Procédure rach avec alignement temporel
CN113615292A (zh) * 2019-03-29 2021-11-05 株式会社Ntt都科摩 用户装置、基站装置和通信方法

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