WO2021088994A1 - Procédé et appareil de correction de fréquence en liaison montante - Google Patents

Procédé et appareil de correction de fréquence en liaison montante Download PDF

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Publication number
WO2021088994A1
WO2021088994A1 PCT/CN2020/127168 CN2020127168W WO2021088994A1 WO 2021088994 A1 WO2021088994 A1 WO 2021088994A1 CN 2020127168 W CN2020127168 W CN 2020127168W WO 2021088994 A1 WO2021088994 A1 WO 2021088994A1
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Prior art keywords
frequency
compensated
procedure
msg1
shift
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PCT/CN2020/127168
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English (en)
Inventor
Chienchun CHENG
Chiahao YU
Hengli CHIN
Hungchen CHEN
Chiahung Lin
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FG Innovation Company Limited
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W56/00—Synchronisation arrangements
    • H04W56/001—Synchronization between nodes
    • H04W56/0015—Synchronization between nodes one node acting as a reference for the others
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W56/00—Synchronisation arrangements
    • H04W56/0035—Synchronisation arrangements detecting errors in frequency or phase
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/14—Relay systems
    • H04B7/15—Active relay systems
    • H04B7/185—Space-based or airborne stations; Stations for satellite systems
    • H04B7/1851—Systems using a satellite or space-based relay

Definitions

  • the present disclosure is generally related to wireless communication, and, more specifically, to a method for uplink (UL) frequency correction for the next generation wireless communication networks.
  • UL uplink
  • 5G fifth generation
  • NR New Radio
  • the 5G NR system is designed to provide flexibility and configurability to optimize the network services and types, accommodating various use cases such as enhanced Mobile Broadband (eMBB) , massive Machine-Type Communication (mMTC) , and Ultra-Reliable and Low-Latency Communication (URLLC) .
  • eMBB enhanced Mobile Broadband
  • mMTC massive Machine-Type Communication
  • URLLC Ultra-Reliable and Low-Latency Communication
  • the present disclosure is directed to a method for UL frequency correction for the next generation wireless communication networks.
  • a method for UL frequency correction performed by a user equipment includes transmitting, to a base station (BS) , a message 1 (Msg1) for a random access (RA) procedure; receiving, from the BS, a message 2 (Msg2) for the RA procedure, the Msg2 indicating a first UL frequency shift; and performing UL frequency correction based on the first UL frequency shift to obtain a first compensated UL frequency after receiving the Msg2.
  • Msg1 message 1
  • Msg2 message 2
  • a UE includes one or more non-transitory computer-readable media having computer-executable instructions embodied thereon and at least one processor coupled to the one or more non-transitory computer-readable media.
  • the at least one processor is configured to execute the computer-executable instructions to transmit, to a BS, a Msg1 for an RA procedure; receive, from the BS, a Msg2 for the RA procedure, the Msg2 indicating a first UL frequency shift; and perform UL frequency correction based on the first UL frequency shift to obtain a first compensated UL frequency after receiving the Msg2.
  • FIG. 1 illustrates a process of receiving a DRX MAC CE according to an example implementation of the present disclosure.
  • FIG. 2 illustrates a process of receiving a DRX MAC CE and a corresponding DRX ambiguous period according to an example implementation of the present disclosure.
  • FIG. 3 illustrates a process of CSI and SRS transmission according to an example implementation of the present disclosure.
  • FIG. 4 illustrates a process of UL frequency compensation for a UE with GNSS capability in a 4-step CBRA procedure according to an example implementation of the present disclosure.
  • FIG. 5 illustrates a process of UL frequency compensation for a UE with GNSS capability in a 4-step CBRA procedure according to another example implementation of the present disclosure.
  • FIG. 6 illustrates a process of UL frequency compensation for a UE without GNSS capability in a 4-step CBRA procedure according to an example implementation of the present disclosure.
  • FIG. 7 illustrates a process of UL frequency compensation for a UE with GNSS capability in a 2-step CBRA procedure according to an example implementation of the present disclosure.
  • FIG. 8 illustrates a process of UL frequency compensation for a UE without GNSS capability in a 2-step CBRA procedure according to an example implementation of the present disclosure.
  • FIG. 9 illustrates a process of UL frequency compensation for a UE with GNSS capability in a CFRA procedure according to an example implementation of the present disclosure.
  • FIG. 10 illustrates a process of UL frequency compensation for a UE without GNSS capability in a CFRA procedure according to an example implementation of the present disclosure.
  • FIG. 11 illustrates a process of UL frequency compensation for a UE with GNSS capability in a fallback procedure according to an example implementation of the present disclosure.
  • FIG. 12 illustrates a process of UL frequency compensation for a UE with GNSS capability in a fallback procedure according to another example implementation of the present disclosure.
  • FIG. 13 illustrates a process of UL frequency compensation for a UE without GNSS capability in a fallback procedure according to an example implementation of the present disclosure.
  • FIG. 14 illustrates a method performed by a UE for UL frequency correction according to an example implementation of the present disclosure.
  • FIG. 15 illustrates a method performed by a UE for UL frequency correction according to another example implementation of the present disclosure.
  • FIG. 16 illustrates a method performed by a UE for UL frequency correction according to still another example implementation of the present disclosure.
  • FIG. 17 illustrates a method performed by a UE for UL frequency correction according to still another example implementation of the present disclosure.
  • FIG. 18 illustrates a block diagram of a node for wireless communication, in accordance with various aspects of the present disclosure.
  • the phrases “in one implementation, ” or “in some implementations, ” may each refer to one or more of the same or different implementations.
  • the term “coupled” is defined as connected whether directly or indirectly via intervening components and is not necessarily limited to physical connections.
  • the term “comprising” means “including, but not necessarily limited to” and specifically indicates open-ended inclusion or membership in the disclosed combination, group, series or equivalent.
  • the expression “at least one of A, B and C” or “at least one of the following: A, B and C” means “only A, or only B, or only C, or any combination of A, B and C. ”
  • system and “network” may be used interchangeably.
  • the term “and/or” is only an association relationship for disclosing associated objects and represents that three relationships may exist such that A and/or B may indicate that A exists alone, A and B exist at the same time, or B exists alone. “A and/or B and/or C” may represent that at least one of A, B, and C exists.
  • the character “/” generally represents that the associated objects are in an “or” relationship.
  • any disclosed network function (s) or algorithm (s) may be implemented by hardware, software or a combination of software and hardware.
  • Disclosed functions may correspond to modules which may be software, hardware, firmware, or any combination thereof.
  • a software implementation may include computer-executable instructions stored on a computer-readable medium such as memory or other type of storage devices.
  • a computer-readable medium such as memory or other type of storage devices.
  • One or more microprocessors or general-purpose computers with communication processing capability may be programmed with corresponding executable instructions and perform the disclosed network function (s) or algorithm (s) .
  • the microprocessors or general-purpose computers may include Applications Specific Integrated Circuitry (ASIC) , programmable logic arrays, and/or using one or more Digital Signal Processors (DSPs) .
  • ASIC Applications Specific Integrated Circuitry
  • DSP Digital Signal Processors
  • the computer-readable medium may include, but is not limited to, Random Access Memory (RAM) , Read-Only Memory (ROM) , Erasable Programmable Read-Only Memory (EPROM) , Electrically Erasable Programmable Read-Only Memory (EEPROM) , flash memory, Compact Disc Read-Only Memory (CD-ROM) , magnetic cassettes, magnetic tape, magnetic disk storage, or any other equivalent medium capable of storing computer-readable instructions.
  • RAM Random Access Memory
  • ROM Read-Only Memory
  • EPROM Erasable Programmable Read-Only Memory
  • EEPROM Electrically Erasable Programmable Read-Only Memory
  • flash memory Compact Disc Read-Only Memory
  • CD-ROM Compact Disc Read-Only Memory
  • magnetic cassettes magnetic tape
  • magnetic disk storage or any other equivalent medium capable of storing computer-readable instructions.
  • a radio communication network architecture such as a Long-Term Evolution (LTE) system, an LTE-Advanced (LTE-A) system, an LTE-Advanced Pro system, or a 5G NR Radio Access Network (RAN) may typically include at least one Base Station (BS) , at least one UE, and one or more optional network elements that provide connection within a network.
  • the UE may communicate with the network such as a Core Network (CN) , an Evolved Packet Core (EPC) network, an Evolved Universal Terrestrial Radio Access Network (E-UTRAN) , a Next-Generation Core (NGC) , a 5G Core (5GC) , or an internet via a RAN established by one or more BSs.
  • CN Core Network
  • EPC Evolved Packet Core
  • E-UTRAN Evolved Universal Terrestrial Radio Access Network
  • NGC Next-Generation Core
  • 5GC 5G Core
  • a UE may include, but is not limited to, a mobile station, a mobile terminal or device, or a user communication radio terminal.
  • the UE may be a portable radio equipment that includes, but is not limited to, a mobile phone, a tablet, a wearable device, a sensor, a vehicle, or a Personal Digital Assistant (PDA) with wireless communication capability.
  • PDA Personal Digital Assistant
  • the UE may be configured to receive and transmit signals over an air interface to one or more cells in a RAN.
  • the BS may be configured to provide communication services according to at least a Radio Access Technology (RAT) such as Worldwide Interoperability for Microwave Access (WiMAX) , Global System for Mobile communications (GSM that is often referred to as 2G) , GSM Enhanced Data rates for GSM Evolution (EDGE) Radio Access Network (GERAN) , General Packet Radio Service (GPRS) , Universal Mobile Telecommunication System (UMTS that is often referred to as 3G) based on basic Wideband-Code Division Multiple Access (W-CDMA) , High-Speed Packet Access (HSPA) , LTE, LTE-A, evolved/enhanced LTE (eLTE) that is LTE connected to 5GC, NR (often referred to as 5G) , and/or LTE-A Pro.
  • RAT Radio Access Technology
  • WiMAX Worldwide Interoperability for Microwave Access
  • GSM Global System for Mobile communications
  • EDGE GSM Enhanced Data rates for GSM Evolution
  • GERAN GSM Enhanced Data
  • the BS may include, but is not limited to, a node B (NB) in the UMTS, an evolved node B (eNB) in LTE or LTE-A, a Radio Network Controller (RNC) in UMTS, a Base Station Controller (BSC) in the GSM/GERAN, a next-generation eNB (ng-eNB) in an Evolved Universal Terrestrial Radio Access (E-UTRA) BS in connection with 5GC, a next-generation Node B (gNB) in the 5G RAN (or in the 5G Access Network (5G-AN) ) , or any other apparatus capable of controlling radio communication and managing radio resources within a cell.
  • the BS may serve one or more UEs via a radio interface.
  • the BS may be operable to provide radio coverage to a specific geographical area using a plurality of cells included in the RAN.
  • the BS may support the operations of the cells.
  • Each cell may be operable to provide services to at least one UE within its radio coverage.
  • Each cell may provide services to serve one or more UEs within its radio coverage such that each cell schedules the downlink (DL) and optionally UL resources to at least one UE within its radio coverage for DL and optionally UL packet transmissions.
  • the BS may communicate with one or more UEs in the radio communication system via the plurality of cells.
  • a cell may allocate Sidelink (SL) resources for supporting Proximity Service (ProSe) , LTE SL services, and/or LTE/NR Vehicle-to-Everything (V2X) service. Each cell may have overlapped coverage areas with other cells.
  • SL Sidelink
  • Proximity Service Proximity Service
  • LTE SL services LTE SL services
  • V2X Vehicle-to-Everything
  • MCG Master Cell Group
  • SCG Secondary Cell Group
  • SpCell Special Cell
  • a Primary Cell may refer to the SpCell of an MCG.
  • a Primary SCG Cell (PSCell) may refer to the SpCell of an SCG.
  • MCG may refer to a group of serving cells associated with the Master Node (MN) , comprising of the SpCell and optionally one or more Secondary Cells (SCells) .
  • SCG may refer to a group of serving cells associated with the Secondary Node (SN) , comprising of the SpCell and optionally one or more SCells .
  • the frame structure for NR supports flexible configurations for accommodating various next-generation (e.g., 5G) communication requirements such as enhanced mobile broadband (eMBB) , massive machine type communication (mMTC) , and ultra reliable and low latency communication (URLLC) , while fulfilling high reliability, high data rate and low latency requirements.
  • 5G next-generation
  • eMBB enhanced mobile broadband
  • mMTC massive machine type communication
  • URLLC ultra reliable and low latency communication
  • OFDM Orthogonal Frequency-Division Multiplexing
  • 3GPP 3 rd Generation Partnership Project
  • the scalable OFDM numerology such as adaptive sub-carrier spacing, channel bandwidth, and Cyclic Prefix (CP) may also be used.
  • coding schemes Two coding schemes are considered for NR: specifically Low-Density Parity-Check (LDPC) code and Polar Code.
  • LDPC Low-Density Parity-Check
  • the coding scheme adaption may be configured based on channel conditions and/or service applications.
  • At least DL transmission data, a guard period, and an UL transmission data should be included in a transmission time interval (TTI) of a single NR frame.
  • TTI transmission time interval
  • the respective portions of the DL transmission data, the guard period, and the UL transmission data should also be configurable based on, for example, the network dynamics of NR.
  • SL resources may also be provided in an NR frame to support ProSe services or V2X services.
  • a Cell Radio network object that can be uniquely identified by a UE from a (cell) identification that is broadcasted over a geographical area from one UTRAN Access Point.
  • a Cell is either FDD or TDD mode.
  • Radio Resource Control RRC _CONNECTED not configured with carrier aggregation (CA) or dual connectivity (DC)
  • RRC_CONNECTED there is only one serving cell, which may be referred to as the primary cell.
  • the term “serving cells” may be used to denote a set of cells including the Special Cell (s) (SpCell) and all secondary cells.
  • SpCell Special Cell
  • a Serving Cell may be a PCell, a PSCell, or an SCell described in the 3GPP Technical Specification (TS) 38.331.
  • Hybrid Automatic Repeat Request (HARQ) is a functionality that ensures delivery between peer entities at Layer 1 (i.e., Physical Layer) .
  • a single HARQ process supports one Transport Block (TB) when the physical layer is not configured for DL/UL spatial multiplexing, and a single HARQ process supports one or multiple TBs when the physical layer is configured for DL/UL spatial multiplexing.
  • HARQ information for DL-shared channel (SCH) or for UL-SCH transmissions may include New Data Indicator (NDI) , Transport Block size (TBS) , Redundancy Version (RV) , and HARQ process identity (ID) .
  • NDI New Data Indicator
  • TBS Transport Block size
  • RV Redundancy Version
  • ID HARQ process identity
  • Hybrid automatic repeat request acknowledgement (HARQ-ACK) : A HARQ-ACK information bit value of 0 represents a negative acknowledgement (NACK) while a HARQ-ACK information bit value of 1 represents a positive acknowledgement (ACK) .
  • a Medium Access Control (MAC) entity can setup one or more timers for individual purposes, for example, triggering some UL signaling retransmission or limiting some UL signaling retransmission period.
  • a timer is running once it is started, until it is stopped or until it expires; otherwise it is not running.
  • a timer can be started if it is not running or restarted if it is running.
  • a timer is started or restarted from its initial value. The initial value may be configured by the gNB via DL RRC signaling, but not limited thereto.
  • BWP Bandwidth Part
  • BA bandwidth adaptation
  • the gNB configures the UE with UL and DL BWP (s) .
  • the gNB configures the UE with DL BWP (s) at least (e.g., there may be none in the UL) .
  • the initial BWP is the BWP used for initial access.
  • the initial BWP is the BWP configured for the UE to first operate at SCell activation.
  • UE may be configured with a first active UL BWP by a firstActiveUplinkBWP information element (IE) .
  • IE firstActiveUplinkBWP information element
  • the firstActiveUplinkBWP IE field contains the ID of the UL BWP to be activated upon performing the RRC (re-) configuration. If the field is absent, the RRC (re-) configuration does not impose a BWP switch.
  • the firstActiveUplinkBWP IE field contains the ID of the UL bandwidth part to be used upon MAC-activation of an SCell.
  • the gNB can dynamically allocate resources to UEs via an RNTI (e.g., C-RNTI, modulation and coding scheme-C-RNTI (MCS-C-RNTI) , configured scheduling-RNTI (CS-RNTI) ) on PDCCH (s) .
  • RNTI e.g., C-RNTI, modulation and coding scheme-C-RNTI (MCS-C-RNTI) , configured scheduling-RNTI (CS-RNTI)
  • MCS-RNTI modulation and coding scheme-C-RNTI
  • CS-RNTI scheduling-RNTI
  • a UE may monitor the PDCCH (s) to find possible assignments when its downlink reception is enabled (activity governed by discontinuous reception (DRX) when configured) .
  • DRX discontinuous reception
  • CA discontinuous reception
  • CA the same C-RNTI applies to all serving cells.
  • the PDCCH can be used to schedule DL transmissions on Physical Downlink Shared Channel (PDSCH) and UL transmissions on
  • Transport Block The data from the upper layer (or MAC) given to the physical layer is basically referred to as the transport block.
  • Non-terrestrial networks refer to networks, or segments of networks, using a spaceborne vehicle for transmission, such as Low Earth Orbiting (LEO) satellites and Geostationary Earth Orbiting (GEO) satellites.
  • LEO Low Earth Orbiting
  • GEO Geostationary Earth Orbiting
  • Transparent GEO satellite network refers to a relay-based NTN, including radio frequency (RF) functions only.
  • RF radio frequency
  • Transparent LEO satellite network refers to a relay-based NTN. In this case, the LEO satellites simply perform amplify-and-forward in space.
  • Regenerative LEO satellite network refers to a network architecture in which LEO satellites have full capability of RAN functions as a base station in NR. In this case, UEs are served directly by the satellites.
  • DRX Discontinuous Reception
  • DRX is used to reduce power consumption of a device (e.g., UE) .
  • the basic mechanism for DRX is a configurable DRX cycle in the device. With a DRX cycle configured, the device monitors the DL control signaling only when active and may sleep with the receiver circuitry switched off for the remaining time. This allows for a significant reduction in power consumption: the longer the cycle, the lower the power consumption in principle. Naturally, this implies restrictions to the scheduler as the device can be reached only in active time according to the DRX operation.
  • MAC CEs are used for control signaling.
  • the MAC CE may provide a faster way to send control signaling than Radio Link Control (RLC) or RRC, with concerns on the restrictions in terms of payload sizes and reliability as those offered by physical-layer control signaling, such as PDCCH or Physical Uplink Control Channel (PUCCH) .
  • RLC Radio Link Control
  • PDCCH Physical Uplink Control Channel
  • the MAC layer inserts MAC CEs into the transport blocks (TBs) to be transmitted over the transport channels.
  • MAC-CEs specified in NR may include a DRX Command MAC CE and a Long DRX Command MAC CE.
  • the DRX Command MAC CE is used to stop drx-onDurationTime, stop drx-InactivityTimer, and start drx-ShortCycleTimer.
  • the Long DRX Command MAC CE is used to stop drx-onDurationTime, stop drx-InactivityTimer, and stop drx-ShortCycleTimer to use the Long DRX cycle.
  • the MAC CE latency may include latency related to MAC CE parsing and may further include latency related to physical layer processing and configuration based on the parsing result.
  • the MAC CE latency is defined from the UE perspective.
  • the MAC CE latency may be the interval between the time of an acknowledgement (ACK) transmission for a PDSCH carrying a MAC CE message and the time that the UE applies the MAC CE message.
  • ACK acknowledgement
  • DRX ambiguous period refers to a time interval that a device (e.g., UE) and the network (NW) have no common understanding of whether DRX MAC CE command is applied by the UE.
  • a device e.g., UE
  • NW network
  • the K0 value may refer to the offset between the DL slot in which the PDCCH for DL scheduling is received and the DL slot in which PDSCH data is scheduled.
  • the K1 value may refer to the offset between the DL slot in which the data is scheduled on PDSCH and the UL slot in which the ACK/NACK feedback for the scheduled PDSCH data needs to be sent.
  • the K2 value may refer to the offset between the DL slot in which the PDCCH for UL scheduling is received and the UL Slot in which the UL data needs to be sent on PUSCH.
  • Doppler shift refers to a shift of the signal frequency due to the relative motion between a receiving device (e.g., UE) and a transmitter (e.g., gNB) .
  • the Doppler shift may depend on the relative speed of the airborne platforms, the speed of the device, and the carrier frequency. In NR Uu interface, the Doppler shift may be less than 5 parts per million (ppm) in general, but in NTN the Doppler shift may be 24 ppm.
  • Random Access (RA) procedure the RA procedure is used when a device has found a cell and may try to access the cell.
  • a 4-step CBRA procedure may include the following steps:
  • Message 1 (Msg1) : UE transmission of a preamble over Physical Random Access Channel (PRACH) .
  • Msg2 Network (NW) transmission of a Random Access Response (RAR) indicating reception of the preamble and providing a time-alignment command adjusting the transmission timing of the device based on the timing of the received preamble.
  • NW Network
  • RAR Random Access Response
  • Msg3 may be the first scheduled transmission of the RA procedure.
  • Msg3 may include a cell-radio network temporary identifier (C-RNTI) MAC CE or common control channel (CCCH) service data unit (SDU) , submitted from an upper layer and associated with the UE Contention Resolution Identity.
  • C-RNTI cell-radio network temporary identifier
  • CCCH common control channel
  • SDU service data unit
  • Msg4 may be used for contention resolution.
  • the UE and the NW may exchange messages (e.g., Msg3 and Msg4) with the aim of resolving potential collisions due to simultaneous transmissions of the same preamble from multiple devices within the cell over the same time/frequency resources. If contention resolution is successful, Msg4 may also transfer the device to the connected state.
  • a 2-step CBRA procedure is an enhancement of the 4-step CBRA procedure.
  • the 2-step CBRA procedure may include the following steps:
  • MsgA may include preamble and payload transmission of the 2-step CBRA procedure.
  • MsgA may include UE transmission of a preamble on PRACH with a possible payload as Msg3 in 4-step CBRA procedure over an associated PUSCH resource (s) .
  • MsgB may be a response to the MsgA in the 2-step CBRA procedure.
  • MsgB may include response (s) for contention resolution, fallback indication (s) , and backoff indication.
  • MsgB may include NW transmission of the response containing information for multiple UEs and addressed to a new MsgB-RNTI.
  • gNB is a node providing NR user plane and control plane protocol terminations towards the UE.
  • the gNB may be connected via the NG interface to the 5GC.
  • ng-eNB is a node providing E-UTRA user plane and control plane protocol terminations towards the UE.
  • the ng-eNB may be connected via the NG interface to the 5GC.
  • a DRX ambiguous period may include PDSCH decoding time (around 1ms) and DRX MAC CE processing time (around 3ms) .
  • the DRX ambiguous period may be set to 4ms as a good trade-off value between companies.
  • the DRX ambiguous period in NR Rel-15 does not consider all possibilities of K1 values.
  • the NW may perform blind decoding on Channel State Information (CSI) or Sounding Reference Signal (SRS) transmissions.
  • CSI Channel State Information
  • SRS Sounding Reference Signal
  • FIG. 1 illustrates a process 100 of receiving a DRX MAC CE according to an example implementation of the present disclosure.
  • the UE receives PDCCH 112 that schedules a DL transmission for DRX MAC CE 114.
  • the offset between the PDCCH 112 and the DRX MAC CE 114 is K0.
  • the DRX MAC CE 114 is received before the DRX ambiguous period.
  • the UE needs to consider the DRX MAC CE 114 when deciding whether to report CSI/SRS in/after symbol n. Therefore, the UE will not report CSI/SRS in/after symbol n.
  • the length of the DRX ambiguous period may be 4ms.
  • the symbol n may refer to a DL symbol n or a UL symbol n in the present disclosure.
  • K1 > 4ms in scenario #1.
  • K1 may be 9ms.
  • NW cannot know whether the UE has received the DRX MAC CE 114 successfully or not before symbol n. Therefore, during the time between symbol n and the time NW receives HARQ ACK or NACK 116, the NW still needs to perform blind decoding for CSI/SRS report.
  • the UE receives PDCCH 122 that schedules a DL transmission for DRX MAC CE 124.
  • the offset between the PDCCH 122 and the DRX MAC CE 124 is K0.
  • the DRX MAC CE 124 is received before the DRX ambiguous period.
  • the UE needs to consider the DRX MAC CE 124 when deciding whether to report CSI/SRS in/after symbol n. Therefore, the UE will not report CSI/SRS in/after symbol n.
  • the length of the DRX ambiguous period may be 4ms.
  • K1 ⁇ 4ms in scenario #2.
  • K1 may be 2ms. Therefore, NW may receive HARQ ACK or NACK 126 before the DRX ambiguous period ends.
  • the NW knows whether the UE has received the DRX MAC CE 124 successfully. If the UE has received the DRX MAC CE 124 correctly, the NW does not need to decode CSI/SRS report in/after symbol n.
  • K_offset may be configured by higher layers and its value may be greater than or equal to the UE-specific TA value.
  • the MAC CE latency may be insufficient to cover the propagation delay. To handle this, the following agreement has been made in RAN1#98-Bis.
  • m is provided by NW via Layer 1 and/or Layer 2 signaling, e.g., Downlink Control Information (DCI) indication and/or RRC messages.
  • DCI Downlink Control Information
  • the value of m may be greater than or equal to the TA value, e.g., up to 540ms for GEO with transparent payloads, plus MAC CE parsing time, e.g., 3ms defined in NR specifications.
  • RTT round trip time
  • DRX ambiguous period cannot cover the scheduling offset, e.g., 24ms, in NTN. If there is no enhancement on the ambiguous period, NW may pay an extra price for blind decoding.
  • the MAC CE latency and the scheduling offset may change with the configuration. This is to accommodate different propagation delays, e.g., LEO, GEO, transparent, or regenerative payloads. As a result, there is a need to provide configurable parameters for the DRX ambiguous period.
  • the DRX ambiguous period is set too long, CSI reporting may be impacted. On the other hand, if the DRX ambiguous period is set too short, NW may need to perform more blind decoding before receiving HARQ feedback.
  • a starting time of the DRX ambiguous period may be defined by the beginning of the OFDM symbol after the last received OFDM symbol containing grants, or assignments, or DRX Command MAC CE, or Long DRX Command MAC CE, or short DRX MAC CE.
  • the starting time of the DRX ambiguous period may be the beginning of the OFDM symbol after the last symbol of the received DRX MAC CE.
  • the DRX ambiguous period may be adapted via at least one of the following options:
  • IE information element
  • SI system information
  • a predefined table that includes values for different NTN scenarios, e.g. LEO or GEO; transparent or regenerative; UE determines the value when the scenario is identified or indicated by NW.
  • dynamic determination by adding up a dynamically indicated value and a semi-statically configured value and/or a predefined term.
  • its associated ambiguous period may be the sum of K1 value indicated by an associated DCI, K_offset value configured by RRC signaling, and a fixed value (e.g., 4ms) .
  • semi-statically determination by adding up a semi-statically configured value and/or a predefined term.
  • its associated ambiguous period may be the sum of K_offset value configured by RRC signaling and a fixed value (e.g., 4ms) .
  • the ideal DRX ambiguous period may prevent NW from performing SRS/CSI blind decoding. To achieve this, the DRX ambiguous period has to cover the time at which the NW receives the HARQ ACK associated with the MAC CE. In one implementation, the DRX ambiguous period may further consider processing delay at the NW side.
  • FIG. 2 illustrates a process 200 of receiving a DRX MAC CE and a corresponding DRX ambiguous period according to an example implementation of the present disclosure.
  • n denotes the slot number for DCI (PDCCH) reception
  • m denotes the slot number for PDSCH reception
  • k denotes the slot number for HARQ feedback.
  • TA refers to the timing advance value, which is an offset between the UE DL timeline and the UE UL timeline.
  • Tp refers to the propagation delay between the UE and the NW.
  • the NW transmits PDCCH in slot n, which schedules a PDSCH in slot m.
  • K0 is the offset between the slot n and the slot m.
  • the UE receives the PDSCH associated with DRX MAC CE in slot m.
  • the UE transmits HARQ ACK associated with the DRX MAC CE in slot k.
  • K1+K_offset is the offset between the slot m and the slot k. It is assumed that a DRX ambiguous period starts from the next OFDM symbol of the last received OFDM symbol containing a PDSCH associated with the DRX MAC CE.
  • the DRX ambiguous period may cover the time at which the NW receives the HARQ ACK. In this case, the DRX ambiguous period ends after the NW identifies the HARQ ACK transmission.
  • the DRX ambiguous period may be determined at least based on an Np value, which approximates the propagation delay Tp between the UE and the NW.
  • the Np value may be derived from K_offset provided by the NW (e.g., via RRC signaling) .
  • the DRX ambiguous period Np + X
  • the DRX ambiguous period K1 + Np + X
  • K1 (e.g., 9ms) may be indicated via L1 signaling (e.g., DCI) .
  • K1 may be a fixed value (e.g., 9ms) .
  • the value of X relates to the MAC CE parsing time, such as 0ms, 3ms or 4ms.
  • the value of X may reflect parsing time on UE and/or NW side.
  • the value of X may be pre-specified in the specifications or may be configured by the NW.
  • Np refers to an approximation for the propagation delay Tp, which may be provided by the NW by at least one of the following manners:
  • Np may be estimated by the UE with Global Navigation Satellite System (GNSS) and satellite ephemeris.
  • GNSS Global Navigation Satellite System
  • satellite ephemeris satellite ephemeris
  • Np (the current TA value) /2; the current TA value may be updated for each received DL TA MAC CE command.
  • Np (the common TA value) /2; the common TA value may be broadcast in SI.
  • Np may reflect the UE-specific RTT (e.g., this value may be associated with K_offset, the current TA value, the common TA value, or their combinations)
  • Np may be configured via RRC, broadcasted via SI, or indicated via DCI.
  • Np may be the maximum propagation delay based on a type of the serving satellite (e.g., GEO, LEO with transparent or with regenerative payloads) . Np may be provided via SI. In one implementation, when UE selects a PLMN ID, the selected ID also implies a type of the serving satellite and the maximum propagation delay.
  • FIG. 3 illustrates a process 300 of CSI and SRS transmission according to an example implementation of the present disclosure.
  • an UL TX scheduled in UL slot p will be time-advanced multiple slots before DL slot p.
  • the UE UL timeline is shifted by a TA value with respect to the UE DL timeline.
  • the DL slot p is associated with the UL slot p.
  • the NW e.g., gNB
  • reception time of the concerned UL TX (scheduled in the UL slot p) may be before the DL slot p.
  • Case 3-1 the UL transmission time is defined by DL slot timing. Therefore, for a UL TX scheduled in a DL symbol p’ in the DL slot p, the actual transmission timing is advanced by the TA value. A CSI report or SRS transmission scheduled in the symbol p’ may be transmitted if its actual transmission time falls within the DRX ambiguous period.
  • One slot may include 14 OFDM symbols as illustrated in FIG. 3.
  • Case 3-2 the UL transmission time is defined by UL slot timing, that is, actual transmission timing. Therefore, for a CSI report or SRS transmission scheduled in UL symbol q’ in the UL slot q, it may be transmitted if the UL symbol q’ falls within the DRX ambiguous period.
  • the MAC entity may be configured by RRC with a DRX functionality that controls the UE’s PDCCH monitoring activity for the MAC entity’s C-RNTI, CS-RNTI, INT-RNTI, SFI-RNTI, SP-CSI-RNTI, TPC-PUCCH-RNTI, TPC-PUSCH-RNTI, and TPC-SRS-RNTI.
  • RRC_CONNECTED if DRX is configured, for all the activated serving cells, the MAC entity may monitor the PDCCH discontinuously using the DRX operation specified in Table 1 below; otherwise, the MAC entity may monitor the PDCCH as specified in 3GPP TS 38.213.
  • the value X’ for the DRX ambiguous period may be determined by one of the following options as disclosed in Case 2:
  • An RA procedure may be triggered by a number of events:
  • Timing Advance Group TAG
  • RA procedures Three types are supported: A 4-step contention-based random access (CBRA) procedure, a 2-step CBRA procedure and a contention-free random access (CFRA) procedure.
  • CBRA contention-based random access
  • CFRA contention-free random access
  • the UE selects the type of RA procedure based on network configuration.
  • a Reference Signal Received Power (RSRP) threshold may be used by the UE to select between the 2-step CBRA and the 4-step CBRA at the initiation of the RA procedure.
  • RSRP Reference Signal Received Power
  • the MsgA of the 2-step CBRA includes a preamble on PRACH and a payload on PUSCH.
  • the UE monitors for a response (MsgB) from the network within a configured window. If contention resolution is successful upon receiving the network response, the UE ends the RA procedure. If a fallback indication is received in MsgB, the UE may fallback to the 4-step CBRA to perform Msg3 transmission and monitor contention resolution (Msg4) . If contention resolution is not successful after Msg3 (re) transmission (s) , the UE may go back to MsgA transmission.
  • the UE may be configured to switch to the 4-step CBRA procedure.
  • the CFRA procedure may include three steps: RA preamble assignment, RA preamble transmission, and RAR reception.
  • the network may explicitly signal which carrier to use (UL or SUL) . Otherwise, the UE selects the SUL carrier if and only if the measured quality of the DL is lower than a broadcast threshold. UE performs carrier selection before selecting between the 2-step CBRA and the 4-step CBRA.
  • the RSRP threshold for the 2-step CBRA and the 4-step CBRA selection may be configured separately for UL and SUL.
  • the 2-step CBRA is only performed on PCell.
  • the first three steps of CBRA always occur on the PCell while contention resolution (the fourth step) may be cross-scheduled by the PCell.
  • the three steps of a CFRA started on the PCell remain on the PCell.
  • CFRA on SCell can only be initiated by the gNB to establish timing advance for a secondary TAG.
  • the CFRA procedure on SCell is initiated by the gNB with a PDCCH order (step 0: preamble assignment) that is sent on a scheduling cell of an activated SCell of the secondary TAG, preamble transmission (step 1) takes place on the indicated SCell, and Random Access Response (step 2) takes place on PCell.
  • the 2-step CBRA procedure may save up to one round trip time (RTT) signaling delay compared to the 4-step CBRA procedure.
  • RTT round trip time
  • NTN scenarios RTT may be up to 540ms.
  • Performance evaluations of the synchronization for DL are encouraged. For these evaluations, for LEO systems, beam specific pre-compensation of the common frequency shift at satellite with respect to the spot beam center can be considered.
  • NW may pre-compensate the Doppler shift on board.
  • the pre-compensated value is referred to as the DL common frequency offset.
  • parameter (s) for frequency correction can be indicated by gNB to UE.
  • NW can indicate some assisted information to UE, such as UL frequency correction or UL/DL frequency compensation at the NW side.
  • some assisted information such as UL frequency correction or UL/DL frequency compensation at the NW side.
  • Pre-compensation with the assisted information may be referred to as a closed-loop solution, while pre-compensation without the assisted information may be referred to as an open-loop solution.
  • a UE has a determined location (e.g., with GNSS capability, with a fixed location, with a fixed moving route, and with satellite ephemeris) , it is possible to predict the Doppler shift between the UE and the serving satellite. It is also possible to have better timing synchronization for the UE oscillator with the help of GNSS than the timing synchronization based on DL reference signals. With this assumption and based on the agreement, the UL frequency control for 4-step CBRA may be implemented via a combination of the open-loop solution and the closed-loop solution.
  • FIG. 4 illustrates a process 400 of UL frequency compensation for a UE with GNSS capability in a 4-step CBRA procedure according to an example implementation of the present disclosure.
  • the UE 420 may estimate the Doppler frequency shift D because the UE 420 has GNSS capability.
  • the UE 420 may apply UL frequency pre-compensation for Msg1 transmission.
  • F stands for the synchronization target of UL frequency.
  • the UE 420 may approximate UL frequency F up to an error term E.
  • a minus D represents the UL frequency pre-compensation, and a plus D represents the impact of the Doppler shift.
  • a pre-compensation of minus D is applied so that the transmitted Msg1 has a frequency of F-D+E.
  • the Msg2 may indicate a UL frequency shift E.
  • the UE 420 may perform UL frequency correction based on the UL frequency shift E to obtain a compensated UL frequency after receiving the Msg2.
  • the UE 420 applies the UL frequency correction for Msg3 transmission.
  • the BS 410 may have full synchronization with the UE 410 after receiving Msg3.
  • the BS 410 can fully synchronize with the UL frequency even if the BS 410 has no information about the Doppler shift D.
  • the BS 410 transmits Msg4 to the UE 420.
  • the BS 410 may stop sending frequency correction in the Msg4 transmission.
  • the process illustrated in FIG. 4 demonstrates a closed-loop control that ensures UL frequency alignment.
  • the BS 410 may not estimate the Doppler shift D even after timing and frequency are synchronized.
  • the BS 410 may send UL frequency correction on Msg4, and there may be no correction carried by Msg2 and no pre-compensation on Msg3.
  • the UL frequency correction carried by Msg2 may be group-based information for more than one UEs.
  • the UL frequency correction carried by Msg2 may use the same MAC RAR by adding a new field or adding new octets to the MAC RAR.
  • a MAC Protocol Data Unit (PDU) (for RAR) may include one or more MAC subPDUs and optionally padding.
  • the UL frequency correction carried by Msg2 may use a new MAC subPDU.
  • a MAC PDU (for RAR) may include a MAC subPDU that is a MAC subheader with a UL frequency offset.
  • Case 5 4-step CBRA, UE has GNSS capability, frequency offset broadcast via SI
  • FIG. 5 illustrates a process 500 of UL frequency compensation for a UE with GNSS capability in a 4-step CBRA procedure according to another example implementation of the present disclosure.
  • UE 520 may use a different pre-compensation value for Msg3 transmission compared to the implementation illustrated in FIG. 4.
  • the UE 520 may apply a common UL frequency offset broadcast by BS 510 via SI.
  • the UE 520 may apply a common UL frequency offset associated with the DL common frequency offset, if broadcast.
  • the UE 520 receives SI broadcast by the BS 510 (e.g., a gNB) .
  • a common UL frequency offset denoted by Dc
  • the UE 520 may obtain or derive the common UL frequency offset Dc via SI.
  • the UE 520 may estimate the Doppler frequency shift D because the UE 520 has GNSS capability.
  • the UE 520 may apply UL frequency pre-compensation for Msg1 transmission. Based on GNSS signal or based on DL signal measurement, the UE 520 may approximate UL frequency F up to an error term E.
  • a pre-compensation of minus D is applied so that the transmitted Msg1 has a frequency of F-D+E.
  • the Msg2 may indicate a UL frequency shift E.
  • the common UL frequency offset Dc may be carried via Msg2 transmission.
  • the UE 520 may obtain or derive the common UL frequency offset Dc via SI or Msg2.
  • the UE 520 may perform UL frequency correction based on the UL frequency shift E and the common UL frequency offset Dc to obtain a compensated UL frequency after receiving the Msg2.
  • the UE 520 applies the UL frequency correction for Msg3 transmission.
  • the UE 520 uses the frequency F-Dc for Msg3 transmission to allow the BS 510 to estimate the term D.
  • the BS 510 may estimate the term D.
  • the BS 510 may transmit Msg4 to the UE 520.
  • the BS 510 may indicate a residual frequency correction term D-Dc in Msg4. That is, the BS 510 can obtain full information about the Doppler shift D and send further UL frequency correction D-Dc via Msg4 transmission.
  • the UE 520 may perform UL frequency correction based on the residual UL frequency correction term D-Dc to obtain a compensated UL frequency after receiving the Msg4.
  • Doppler pre-compensation is solely performed by the UE 520 for Msg1 transmission.
  • a predefined closed-loop behavior is applied by the UE 520 to apply a broadcast term (Dc) and a dedicatedly signaled term (E) .
  • Dc broadcast term
  • E dedicatedly signaled term
  • a closed-loop differential term on top of the pre-compensation value from previous transmission (s) is signaled to update the pre-compensation value.
  • FIG. 6 illustrates a process 600 of UL frequency compensation for a UE without GNSS capability in a 4-step CBRA procedure according to an example implementation of the present disclosure.
  • the UE 620 may not predict the Doppler shift because the UE 620 has neither GNSS capability nor satellite ephemeris.
  • the BS 610 may broadcast the UL frequency offset via SI to prevent UL interference between UEs.
  • the UE 620 receives SI broadcast by the BS 610.
  • the UE 620 may obtain or derive the common UL frequency offset Dc via SI.
  • the UE 620 may perform UL frequency pre-compensation for Msg1 transmission based on the common UL frequency offset Dc.
  • the UE 620 may approximate UL frequency F up to an error term E’.
  • a pre-compensation of minus Dc is applied so that the transmitted Msg1 has a frequency of F-Dc+E’.
  • error term E A different notation for the error term E’ (UE has no GNSS capability) is used here to differentiate from the error term E (UE has GNSS capability) previously disclosed.
  • the error term E’ may be greater than the error term E.
  • the error term E’ may be contributed from (1) DL frequency and timing errors via estimation of DL reference signals and (2) the residual UL frequency offset given the common UL frequency offset Dc, which may be significant if the UE is at the cell or beam edge.
  • the latter term may be up to 8 ppm for a case of LEO-600km.
  • the BS 610 may estimate the UL frequency correction upon receiving Msg1. After NTN channel distortion, a frequency of F-Dc+E’ +D is perceived at the BS 610. In action 634, the BS 610 transmits Msg2 to the UE.
  • the Msg2 may indicate a UL frequency shift E’ +D-Dc.
  • the UE 620 may perform UL frequency correction based on the UL frequency shift E’ +D-Dc to obtain a compensated UL frequency after receiving the Msg2.
  • the UE 620 applies the UL frequency correction for Msg3 transmission.
  • the BS 610 may have full synchronization with the UE 610 after receiving Msg3.
  • the BS 610 can fully synchronize with the UL frequency.
  • the BS 610 has no information about the Doppler shift D.
  • the BS 610 transmits Msg4 to the UE 620.
  • the BS 610 may stop sending frequency correction in the Msg4 transmission.
  • the UE 620 may report the Doppler shift via Msg3 to make the BS 610 aware of the Doppler shift D.
  • FIG. 7 illustrates a process 700 of UL frequency compensation for a UE with GNSS capability in a 2-step CBRA procedure according to an example implementation of the present disclosure.
  • the UE 720 has GNSS capability and satellite ephemeris.
  • the UE 720 may estimate the Doppler frequency shift D because the UE 720 has GNSS capability.
  • the UE 720 may apply UL frequency pre-compensation for MsgA transmission.
  • a pre-compensation of minus D is applied so that the transmitted MsgA has a frequency of F-D+E.
  • the BS 710 may estimate the error term E and indicate the error term E to the UE 720 in MsgB.
  • the BS 710 transmits MsgB to the UE.
  • the MsgB may indicate a UL frequency shift E.
  • the UE 720 may perform UL frequency correction based on the UL frequency shift E to obtain a compensated UL frequency after receiving the MsgB.
  • the BS 710 can fully synchronize with the UL frequency even if the BS 710 has no information about the Doppler shift D.
  • the UE 720 may report the Doppler shift D to the BS 710 via MsgA.
  • the UL frequency correction carried by MsgB may be group-based information for more than one UEs. In one implementation, the UL frequency correction may be UE-specific information via adding new fields or new octets in the RAR message.
  • FIG. 8 illustrates a process 800 of UL frequency compensation for a UE without GNSS capability in a 2-step CBRA procedure according to an example implementation of the present disclosure.
  • the UE 820 may not predict the Doppler shift because the UE 820 has neither GNSS capability nor satellite ephemeris.
  • the BS 810 may broadcast the UL frequency offset via SI.
  • the UE 820 receives SI broadcast by the BS 810.
  • the UE 820 may obtain or derive the common UL frequency offset Dc via SI.
  • the UE 820 may perform UL frequency pre-compensation for MsgA transmission based on the common UL frequency offset Dc.
  • the UE 820 may approximate UL frequency F up to an error term E’.
  • a pre-compensation of minus Dc is applied so that the transmitted MsgA has a frequency of F-Dc+E’.
  • the BS 810 may estimate the UL frequency correction upon receiving MsgA. After NTN channel distortion, a frequency of F-Dc+E’ +D is perceived at the BS 810.
  • the BS 810 transmits MsgB to the UE 820.
  • the MsgB may indicate a UL frequency shift E’ +D-Dc.
  • the UE 820 may perform UL frequency correction based on the UL frequency shift E’ +D-Dc to obtain a compensated UL frequency after receiving the MsgB. Frequency alignment between the BS 810 and the UE 820 can be achieved.
  • the BS 810 can fully synchronize with the UL frequency even if the BS 810 has no information about the Doppler shift D.
  • the UE 820 may report the Doppler shift D to the BS 810 via MsgA.
  • the CFRA procedure is similar to the 4-step CBRA procedure illustrated in FIG. 4 –FIG. 6 except that there is no Msg3 and Msg4 for contention resolution. Therefore, there may be no easy way for the BS to estimate the Doppler shift but let UE report the Doppler shift after the CFRA procedure.
  • FIG. 9 illustrates a process 900 of UL frequency compensation for a UE with GNSS capability in a CFRA procedure according to an example implementation of the present disclosure.
  • the BS 910 may transmit RA preamble assignment to the UE 920.
  • the UE 920 has GNSS capability and satellite ephemeris.
  • the UE 920 may estimate the Doppler frequency shift D because the UE 920 has GNSS capability.
  • the UE 920 may apply UL frequency pre-compensation for Msg1 transmission. For Msg1 transmission, a pre-compensation of minus D is applied so that the transmitted Msg1 has a frequency of F-D+E.
  • the BS 910 may estimate the error term E and indicate the error term E to the UE 920 in Msg2.
  • the BS 910 transmits Msg2 to the UE.
  • the Msg2 may indicate a UL frequency shift E.
  • the UE 920 may perform UL frequency correction based on the UL frequency shift E to obtain a compensated UL frequency after receiving the Msg2.
  • the BS 910 can fully synchronize with the UL frequency even if the BS 910 has no information about the Doppler shift D.
  • FIG. 10 illustrates a process 1000 of UL frequency compensation for a UE without GNSS capability in a CFRA procedure according to an example implementation of the present disclosure.
  • the UE 1020 may not predict the Doppler shift because the UE 1020 has neither GNSS capability nor satellite ephemeris.
  • the BS 1010 may indicate the UL frequency offset via an RA preamble assignment.
  • the UE 1020 receives the RA preamble assignment from the BS 1010.
  • the UE 1020 may obtain or derive the common UL frequency offset Dc via the RA preamble assignment.
  • the UE 1020 may perform UL frequency pre-compensation for Msg1 transmission based on the common UL frequency offset Dc.
  • the UE 1020 may approximate UL frequency F up to an error term E’.
  • a pre-compensation of minus Dc is applied so that the transmitted Msg1 has a frequency of F-Dc+E’.
  • the BS 1010 may estimate the UL frequency correction upon receiving Msg1. After NTN channel distortion, a frequency of F-Dc+E’ +D is perceived at the BS 1010.
  • the BS 1010 transmits Msg2 to the UE 1020.
  • the Msg2 may indicate a UL frequency shift E’ +D-Dc.
  • the UE 1020 may perform UL frequency correction based on the UL frequency shift E’ +D-Dc to obtain a compensated UL frequency after receiving the Msg2.
  • the BS 1010 can fully synchronize with the UL frequency even if the BS 1010 has no information about the Doppler shift D.
  • FIG. 11 illustrates a process 1100 of UL frequency compensation for a UE with GNSS capability in a fallback procedure according to an example implementation of the present disclosure.
  • the UE 1120 may estimate the Doppler frequency shift D because the UE 1120 has GNSS capability.
  • the UE 1120 may apply UL frequency pre-compensation for MsgA transmission.
  • a pre-compensation of minus D is applied so that the transmitted MsgA has a frequency of F-D+E.
  • the BS 1110 may estimate the error term E and indicate the error term E to the UE 1120 in MsgB.
  • the BS 1110 transmits MsgB to the UE 1120.
  • the MsgB may indicate a UL frequency shift E.
  • the MsgB may further indicate the UE 1110 to fallback from the 2-step CBRA to the 4-step CBRA.
  • the MsgB may carry a fallback indication or the MsgB may be used as means for the fallback indication.
  • the UE 1110 may determine to fallback to the 4-step CBRA according to the fallback indication and thus transmit Msg3 subsequently.
  • the UE 1120 may perform UL frequency correction based on the UL frequency shift E to obtain a compensated UL frequency after receiving the MsgB.
  • the UE 1120 applies the UL frequency correction for Msg3 transmission.
  • the BS 1110 may have full synchronization with the UE 1110 after receiving Msg3.
  • the BS 1110 can fully synchronize with the UL frequency even if the BS 1110 has no information about the Doppler shift D.
  • the BS 1110 transmits Msg4 to the UE 1120.
  • the BS 1110 may stop sending frequency correction in the Msg4 transmission.
  • FIG. 12 illustrates a process 1200 of UL frequency compensation for a UE with GNSS capability in a fallback procedure according to another example implementation of the present disclosure.
  • UE 1220 may use a different pre-compensation value for Msg3 transmission compared to the implementation illustrated in FIG. 11.
  • the UE 1220 may apply a common UL frequency offset broadcast by BS 1210 via SI.
  • the UE 1220 may apply a common UL frequency offset associated with the DL common frequency offset, if broadcast.
  • the UE 1220 receives SI broadcast by the BS 1210.
  • a common UL frequency offset denoted by Dc
  • Dc a common UL frequency offset
  • the UE 1220 may obtain or derive the common UL frequency offset Dc via SI.
  • the UE 1220 may estimate the Doppler frequency shift D because the UE 1220 has GNSS capability.
  • the UE 1220 may apply UL frequency pre-compensation for MsgA transmission. Based on GNSS signal or based on DL signal measurement, the UE 1220 may approximate UL frequency F up to an error term E.
  • a pre-compensation of minus D is applied so that the transmitted MsgA has a frequency of F-D+E.
  • the BS 1210 may estimate the error term E and indicate the error term E to the UE 1220 in MsgB.
  • the BS 1210 transmits MsgB to the UE 1220.
  • the MsgB may indicate a UL frequency shift E.
  • the MsgB may further indicate the UE 1210 to fallback from the 2-step CBRA to the 4-step CBRA.
  • the MsgB may carry a fallback indication or the MsgB may be used as means for the fallback indication.
  • the UE 1210 may determine to fallback to the 4-step CBRA according to the fallback indication and thus transmit Msg3 subsequently.
  • the common UL frequency offset Dc may be carried via MsgB transmission.
  • the UE 1220 may obtain or derive the common UL frequency offset Dc via SI or MsgB.
  • the UE 1220 may perform UL frequency correction based on the UL frequency shift E and the common UL frequency offset Dc to obtain a compensated UL frequency after receiving the MsgB.
  • the UE 1220 applies the UL frequency correction for Msg3 transmission.
  • the UE 1220 uses the frequency F-Dc for Msg3 transmission to allow the BS 1210 to estimate the term D.
  • the BS 1210 may estimate the term D.
  • the BS 1210 may transmit Msg4 to the UE 1220.
  • the BS 1210 may indicate a residual frequency correction term D-Dc in Msg4. That is, the BS 1210 can obtain full information about the Doppler shift D and send further UL frequency correction D-Dc via Msg4 transmission.
  • the UE 1220 may perform UL frequency correction based on the residual UL frequency correction term D-Dc to obtain a compensated UL frequency after receiving the Msg4.
  • FIG. 13 illustrates a process 1300 of UL frequency compensation for a UE without GNSS capability in a fallback procedure according to an example implementation of the present disclosure.
  • the UE 1320 may not predict the Doppler shift because the UE 1320 has neither GNSS capability nor satellite ephemeris.
  • the BS 1310 may broadcast the UL frequency offset via SI.
  • the UE 1320 receives SI broadcast by the BS 1310.
  • the UE 1320 may obtain or derive the common UL frequency offset Dc via SI.
  • the UE 1320 may perform UL frequency pre-compensation for MsgA transmission based on the common UL frequency offset Dc.
  • the UE 1320 may approximate UL frequency F up to an error term E’.
  • a pre-compensation of minus Dc is applied so that the transmitted MsgA has a frequency of F-Dc+E’.
  • the BS 1310 may estimate the UL frequency correction upon receiving MsgA. After NTN channel distortion, a frequency of F-Dc+E’ +D is perceived at the BS 1310.
  • the BS 1310 transmits MsgB to the UE.
  • the MsgB may indicate a UL frequency shift E’ +D-Dc.
  • the MsgB may further indicate the UE 1310 to fallback from the 2-step CBRA to the 4-step CBRA.
  • the UE 1310 may determine to fallback to the 4-step CBRA according to the fallback indication (e.g., carried in the MsgB) and thus transmit Msg3 subsequently.
  • the UE 1320 may perform UL frequency correction based on the UL frequency shift E’+D-Dc to obtain a compensated UL frequency after receiving the MsgB.
  • the UE 1320 applies the UL frequency correction for Msg3 transmission.
  • the BS 1310 may have full synchronization with the UE 1310 after receiving Msg3.
  • the BS 1310 can fully synchronize with the UL frequency.
  • the BS 1310 has no information about the Doppler shift D.
  • the BS 1310 transmits Msg4 to the UE 1320.
  • the BS 1310 may stop sending frequency correction in the Msg4 transmission.
  • the UL frequency control for PUCCH or PUSCH may be based on a combination of:
  • Open-loop UL frequency control including support for residual UL frequency compensation, where the device estimates the UL frequency based on downlink measurements and sets the frequency correction accordingly.
  • Closed-loop UL frequency control based on explicit UL frequency control commands provided by the network. In practice, these commands may be determined based on prior network measurements of the received UL frequency.
  • UL frequency control for PUSCH or PUCCH transmissions may be described by the following expression:
  • F_U F_p + F_c, if F_min ⁇ F_p+F_c ⁇ F_max
  • F_U F_max, if F_p+F_c > F_max
  • F_U F_min, if F_p+F_c ⁇ F_min
  • F_U refers to the adjusted/compensated UL frequency that the UE uses for PUSCH or PUCCH transmission.
  • F_p is the UL frequency estimated by the UE via some information from NW and/or GNSS.
  • F_c is the UL frequency correction indicated by NW.
  • F_max is the maximum value of the adjusted/compensated UL frequency. F_max may be configured via an RRC message or be broadcast via SI.
  • F_min is the minimum value of the adjusted/compensated UL frequency. F_min may be configured via an RRC message or broadcast via SI.
  • Assistance information for the UE to perform estimation on F_p may be broadcast via SI (e.g., DL common frequency shift/offset, DL common TA, maximum RTT in the serving cell/beam/BWP, or the UL common frequency shift/offset) , configured via an RRC message, or carried via PLMN (e.g., satellite types) .
  • SI e.g., DL common frequency shift/offset, DL common TA, maximum RTT in the serving cell/beam/BWP, or the UL common frequency shift/offset
  • PLMN e.g., satellite types
  • F_c may be provided/derived based on UL frequency control command (s) , which may be indicated via L1 signaling (e.g., DCI) , indicated via L2 command (e.g., MAC CE) , or configured via an RRC message.
  • L1 signaling e.g., DCI
  • L2 command e.g., MAC CE
  • the alignment may last for a given period specified by a frequency control timer.
  • the UE may receive, from the BS, a configuration message to configure a frequency control timer.
  • the compensated frequency (frequency alignment) is valid when the frequency control timer is running.
  • the UE may perform UL transmission when the frequency control timer is running.
  • the compensated frequency (frequency alignment) is not valid when the frequency control timer expires.
  • a resynchronization procedure between the UE and the BS may be needed when the frequency control timer expires.
  • the UE may initiate a new RA procedure for UL frequency correction when the frequency control timer expires.
  • the UE may restart the frequency control timer when the UE receives a frequency control command from the BS.
  • FIG. 14 illustrates a method 1400 performed by a UE for UL frequency correction according to an example implementation of the present disclosure.
  • the UE may transmit, to a BS, a Msg1 for an RA procedure.
  • the Msg1 in action 1402 may refer to the Msg1 in the 4-step CBRA, the MsgA in the 2-step CBRA, or the Msg1 in the CFRA.
  • the UE may receive, from the BS, a Msg2 for the RA procedure, the Msg2 indicating a first UL frequency shift.
  • the Msg2 in action 1404 may refer to the Msg2 in the 4-step CBRA, the MsgB in the 2-step CBRA, or the Msg2 in the CFRA.
  • the first UL frequency shift may be the term E disclosed in Cases 4, 5, 7, 9, 11 and 12 or the term E’ +D-Dc disclosed in Cases 6, 8, 10 and 13.
  • the UE may perform UL frequency correction based on the first UL frequency shift to obtain a first compensated UL frequency after receiving the Msg2.
  • the UE may receive, from the BS, a configuration message that indicates at least one of a maximum value of the first compensated UL frequency and a minimum value of the first compensated UL frequency.
  • FIG. 15 illustrates a method 1500 performed by a UE for UL frequency correction according to another example implementation of the present disclosure.
  • Description about actions 1512, 1514 and 1516 in FIG. 15 may be referred to actions 1402, 1404 and 1406, respectively, in Fig. 14.
  • the UE may estimate a second UL frequency shift before transmitting the Msg1.
  • the UE may perform action 1502 if the UE has GNSS capability.
  • the second UL frequency shift may refer to the Doppler shift D in Cases 4, 5, 7, 9, 11 and 12.
  • the UE may perform UL frequency pre-compensation based on the second UL frequency shift to obtain a second compensated UL frequency that is used for transmitting the Msg1.
  • Action 1502 and action 1504 may be omitted in some implementations.
  • the UE may transmit, to the BS, a Msg3 for the RA procedure using the first compensated UL frequency, which is obtained in action 1516.
  • Action 1518 may be omitted in some implementations, such as RA procedures that do not require Msg3 transmission.
  • FIG. 16 illustrates a method 1600 performed by a UE for UL frequency correction according to still another example implementation of the present disclosure.
  • Description about actions 1612, 1614 and 1616 in FIG. 16 may be referred to actions 1402, 1404 and 1406, respectively, in Fig. 14.
  • the UE may receive, from the BS, broadcast system information that indicates a second UL frequency shift before transmitting the Msg1.
  • the UE may perform action 1602 if the UE has no GNSS capability.
  • the second UL frequency shift may refer to the common UL frequency offset Dc in Cases 6, 8, 10 and 13.
  • Action 1602 may be omitted in some implementations.
  • the UE may perform UL frequency pre-compensation based on the second UL frequency shift to obtain a second compensated UL frequency that is used for transmitting the Msg1.
  • Action 1604 may be omitted in some implementations.
  • the second UL frequency shift may be applied by the UE for Msg3 transmission instead of Msg1 transmission.
  • the UE may transmit, to the BS, a Msg3 for the RA procedure using the first compensated UL frequency, which is obtained is action 1616.
  • Action 1618 may be omitted in some implementations, such as RA procedures that do not require Msg3 transmission.
  • FIG. 17 illustrates a method 1700 performed by a UE for UL frequency correction according to still another example implementation of the present disclosure.
  • Description about actions 1702, 1712 and 1714 in FIG. 17 may be referred to actions 1602, 1612 and 1614, respectively, in Fig. 16.
  • the UE may perform UL frequency correction based on the first UL frequency shift (indicated by Msg2 in action 1714) and the second UL frequency shift (Dc obtained in action 1702) to obtain a first compensated UL frequency after receiving the Msg2.
  • the UE may transmit, to the BS, a Msg3 for the RA procedure using the first compensated UL frequency.
  • Action 1718 may be omitted in some implementations, such as RA procedures that do not require Msg3 transmission.
  • the UE may receive, from the BS, a Msg4 for the RA procedure, the Msg4 indicating a third UL frequency shift.
  • the UE may perform UL frequency correction based on the third UL frequency shift to obtain a second compensated UL frequency after receiving the Msg4.
  • Action 1722 and action 1724 may be omitted in some implementations, such as RA procedures that do not require Msg4 transmission.
  • FIG. 18 illustrates a block diagram of a node 1800 for wireless communication, in accordance with various aspects of the present disclosure.
  • a node 1800 may include a transceiver 1820, a processor 1826, a memory 1828, one or more presentation components 1834, and at least one antenna 1836.
  • the node 1800 may also include a radio frequency (RF) spectrum band module, a base station communications module, a network communications module, and a system communications management module, Input /Output (I/O) ports, I/O components, and a power supply (not illustrated in FIG. 18) .
  • RF radio frequency
  • the node 1800 may be a UE or a BS that performs various functions disclosed with reference to FIGS. 1 through 17.
  • the transceiver 1820 has a transmitter 1822 (e.g., transmitting/transmission circuitry) and a receiver 1824 (e.g., receiving/reception circuitry) and may be configured to transmit and/or receive time and/or frequency resource partitioning information.
  • the transceiver 1820 may be configured to transmit in different types of subframes and slots including, but not limited to, usable, non-usable and flexibly usable subframes and slot formats.
  • the transceiver 1820 may be configured to receive data and control channels.
  • the node 1800 may include a variety of computer-readable media.
  • Computer-readable media may be any available media that may be accessed by the node 1800 and include both volatile (and non-volatile) media, and removable (and non-removable) media.
  • the computer-readable media may include computer-storage media and communication media.
  • Computer-storage media may include both volatile (and/or non-volatile) media, and removable (and/or non-removable) media implemented in any method or technology for storage of information such as computer-readable instructions, data structures, program modules or data.
  • Computer-storage media may include RAM, ROM, EPROM, EEPROM, flash memory (or other memory technology) , CD-ROM, Digital Versatile Disks (DVD) (or other optical disk storage) , magnetic cassettes, magnetic tape, magnetic disk storage (or other magnetic storage devices) , etc.
  • Computer storage media may not include a propagated data signal.
  • Communication media may typically embody computer-readable instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transport mechanisms and include any information delivery media.
  • modulated data signal may refer a signal that has one or more of its characteristics set or changed in such a manner as to encode information in the signal.
  • Communication media may include wired media such as a wired network or direct-wired connection, and wireless media such as acoustic, RF, infrared and other wireless media. Combinations of any of the previously disclosed components should also be included within the scope of computer-readable media.
  • the memory 1828 may include computer-storage media in the form of volatile and/or non-volatile memory.
  • the memory 1828 may be removable, non-removable, or a combination thereof.
  • Example memory may include solid-state memory, hard drives, optical-disc drives, etc.
  • the memory 1828 may store computer-readable and/or computer-executable instructions 1832 (e.g., software codes) that are configured to, when executed, cause the processor 1826 to perform various functions disclosed herein, for example, with reference to Figs. 1 through 17.
  • the instructions 1832 may not be directly executable by the processor 1826 but be configured to cause the node 1800 (e.g., when compiled and executed) to perform various functions disclosed herein.
  • the processor 1826 may include an intelligent hardware device, e.g., a Central Processing Unit (CPU) , a microcontroller, an ASIC, etc.
  • the processor 1826 may include memory.
  • the processor 1826 may process the data 1830 and the instructions 1832 received from the memory 1828, and information transmitted and received via the transceiver 1820, the base band communications module, and/or the network communications module.
  • the processor 1826 may also process information to provide to the transceiver 1820 for transmission via the antenna 1836 to the network communications module for transmission to a CN.
  • One or more presentation components 1834 may present data indications to a person or another device.
  • Examples of presentation components 1834 may include a display device, a speaker, a printing component, a vibrating component, etc.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

La présente invention concerne un procédé de correction de fréquence en liaison montante (UL) effectué par un équipement utilisateur (UE). Le procédé consiste à transmettre, à une station de base (BS), un message 1 (Msg1) pour un accès aléatoire (RA) ; recevoir, de la BS, un message 2 (Msg2) pour la procédure RA, le Msg2 indiquant un premier décalage de fréquence UL ; et effectuer une correction de fréquence UL sur la base du premier décalage de fréquence UL pour obtenir une première fréquence UL compensée après réception du Msg2.
PCT/CN2020/127168 2019-11-08 2020-11-06 Procédé et appareil de correction de fréquence en liaison montante WO2021088994A1 (fr)

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