WO2024065689A1

WO2024065689A1 - Method of reporting timing information and method of timing information indication in multi-trp scenario and related devices

Info

Publication number: WO2024065689A1
Application number: PCT/CN2022/123308
Authority: WO
Inventors: Kai Liu
Original assignee: Shenzhen TCL New Technology Co Ltd
Current assignee: Shenzhen TCL New Technology Co Ltd
Priority date: 2022-09-30
Filing date: 2022-09-30
Publication date: 2024-04-04
Anticipated expiration: 2025-03-30
Also published as: CN119999126A

Abstract

A method of reporting timing information and a method of timing information indication in multiple transmission-reception point (multi-TRP) scenario and related devices are provided. The method of reporting timing information, performed by a user equipment (UE), including reporting information through physical uplink control channel (PUCCH) or physical uplink shared channel (PUSCH), wherein the information is at least about timing advance (TA). The report information can help TRPs to schedule UL transmission better to avoid UL transmission overlapping.

Description

METHOD OF REPORTING TIMING INFORMATION AND METHOD OF TIMING INFORMATION INDICATION IN MULTI-TRP SCENARIO AND RELATED DEVICES

TECHNICAL FIELD

The present application relates to wireless communication technologies, and more particularly, to a method of reporting timing information and a method of timing information indication in multiple transmission-reception point (multi-TRP) scenario and related devices such as a user equipment (UE) and a TRP.

BACKGROUND ART

Wireless communication systems, such as the third-generation (3G) of mobile telephone standards and technology are well known. Such 3G standards and technology have been developed by the Third Generation Partnership Project (3GPP) . The 3rd generation of wireless communications has generally been developed to support macro-cell mobile phone communications. Communication systems and networks have developed towards being a broadband and mobile system. In cellular wireless communication systems, user equipment (UE) is connected by a wireless link to a radio access network (RAN) . The RAN includes a set of base stations (BSs) which provide wireless links to the UEs located in cells covered by the base stations, and an interface to a core network (CN) which provides overall network control. The RAN and CN each conducts respective functions in relation to the overall network.

The 3GPP has developed the so-called Long-Term Evolution (LTE) system, namely, an Evolved Universal Mobile Telecommunication System Territorial Radio Access Network (E-UTRAN) , for a mobile access network where one or more macro-cells are supported by base station knowns as an eNodeB or eNB (evolved NodeB) . More recently, LTE is evolving further towards the so-called 5G or NR (new radio) systems where one or more cells are supported by base stations known as a next generation Node B called gNodeB (gNB) .

The 5G New Radio (NR) standard will support a multitude of different services each with very different requirements. These services include Enhanced Mobile Broadband (eMBB) for high data rate transmission, Ultra-Reliable Low Latency Communication (URLLC) for devices requiring low latency and high link reliability and Massive Machine-Type Communication (mMTC) to support a large number of low-power devices for a long life-time requiring highly energy efficient communication.

Multiple-input multiple-output (MIMO) is an effective approach to enhance the capacity of a radio link due to the multiplexing of both transmit and receive antennas. MIMO refers to a practical technique for sending and receiving more than one data signal simultaneously over the same radio channel, which improves the performance of spectral efficiency greatly. Below a quick overview is given about what progress has been achieved to enable the use of multi-TRP transmission which is one of the key technology of MIMO in an efficient manner.

MIMO is one of the key technologies in NR systems and is successful in commercial deployment. In the communication system of MIMO, both UE and base station comprise of a large number of antenna elements. Especially for base station, these antenna elements can be distributed in different panels, as shown in FIG. 1. Each panel is placed at different position such that base station can communicate with UE better. Specifically, panels at different positions are named as multi-TRP in current spec. Both DL and UL channels can benefit from multi-TRP transmission by leveraging spatial diversity to improve the throughput and reliability of transmission in case of unpredictable blockage between a TRP and a UE, especially in FR2.

In multi-TRP scenario, UE can receive DL signals from different TRPs or transmit UL signals to different TRPs. However, as shown in FIG. 2, different distances from UE to different TRPs result in different reception times of UL signals for different TRPs. In current spec, each UE maintains only one timing advance (TA) value in spite of multi-TRP. Maintaining only one TA value means that UE transmitting different UL signals to different TRPs is the same time in advance. UL signal transmission with the same time in advance may lower performance of UL signals due to lower orthogonality with other UL signals transmitted by another UE.

In Rel-18 WID, two TA values are introduced in multi-TRP scenario. Two TAs can let UE transmit different UL signals to different TRPs at different time in advance. Two TAs can make sure the performance of UL signals. However, two TAs also lead to some problems, such as UL transmission overlapping, UL resource multiplexing and so on.

Related arts:

In current spec, the time quantity of UL TA is calculated by T _TA = (N _TA + N _TA, _offset) T _c, where N _TA, _offset is provided by the higher parameter n-TimingAdvanceOffset, N _TA is indicated by the absolute or relative TAC (timing advance command) MAC CE indirectly, and T _c = 0.509 ns. The absolute TAC MAC CE indicates T _A = 0, 1, 2, …, 3846 and N _TA = T _A ·16 ·64 /2 ^μ for SCS of 2 ^μ ·15 kHz. The relative TAC MAC CE indicates adjustment of N _{TA_old} to N _{TA_new} by T _A = 0, 1, 2, …, 63 and N _{TA_new} = N _{TA_old} + (T _A -31) ·16 ·64 /2 ^μ for SCS of 2 ^μ ·15 kHz. The TAC field is 12 bits or 6 bits in the absolute or relative TAC MAC CE.

In current spec, the duration time of a cyclic prefix for SCS of 2 ^μ ·15 kHz can be calculated by T _CP = N _CP ·T _C where the formula of N _CP is shown below.

In 3rd Generation Partnership Project (3GPP) RAN1#109-e meeting, the related agreements are shown as follows.

Agreement

Enhancement on two TAs for UL multi-DCI for multi-TRP operation is supported in Rel-18.

Note 1: whether (1) the network signals two TACs or (2) the network signals one TAC and the UE deriving the second TA can be further studied.

Note 2: evaluations can be considered on as-needed basis.

Agreement

For multi-DCI multi-TRP operation with two TAs, study the following alternatives:

● Alt 1: two reference timings are considered

● Alt 2: one reference timing is considered

Note: reference timing above is the timing of the DL reception

Agreement

For multi-DCI multi-TRP operation with two TAs, study the following alternatives further in Rel-18:

● Alt 1: one n-TimingAdvanceOffset value per serving cell

● Alt 2: two n-TimingAdvanceOffset value per serving cell

In 3rd Generation Partnership Project (3GPP) RAN1#110-e meeting, the related agreements are shown as follows.

Agreement

For multi-DCI based multi-TRP operation with two TAs, study how to handle overlapping part between two UL transmissions associated with two TAs, where the study includes:

○ whether to introduce scheduling restriction in overlapping part

○ whether to introduce dropping rules

○ whether specification impact is needed, or if the issue can be handled via implementation

○ whether to allow overlapped transmission in case the UE supports STxMP transmission (if STxMP feature is agreed in NR Rel-18)

Agreement

For multi-DCI multi-TRP operation with two TAs, up to two n-TimingAdvanceOffset value per serving cell is supported

Some Tdocs present that time duration of the DL time offset is not larger than that of a cyclic prefix (CP) .

SUMMARY

The objective of the present application is to provide a method of reporting timing information and a method of timing information indication in multi-TRP scenario and related devices for solving issues in the prior arts, scheduling UL transmission better, avoiding UL transmission overlapping, or providing a good communication performance.

In a first aspect, an embodiment of the present application provides a method of reporting timing information in multi-TRP scenario, performed by a user equipment (UE) in a network, the method including: reporting information through physical uplink control channel (PUCCH) or physical uplink shared channel (PUSCH) , wherein the information is at least about timing advance (TA) .

In a second aspect, an embodiment of the present application provides a method of timing information indication in multi-TRP scenario, performed by a TRP in a network, the method including: by transmitting a signaling to a user equipment (UE) , informing the UE to report information at least about timing advance (TA) .

In a third aspect, an embodiment of the present application provides a method of reporting timing information in multi-TRP scenario, performed by a user equipment (UE) in a network, the method including: reporting information through physical uplink control channel (PUCCH) or physical uplink shared channel (PUSCH) , wherein the information is at least about a difference between two downlink (DL) reception timings corresponding to a first TRP and a second TRP.

In a fourth aspect, an embodiment of the present application provides a method of timing information indication in multi-TRP scenario, performed by a TRP in a network, the method including: by transmitting a signaling to a user equipment (UE) , informing the UE to report information at least about a difference between two downlink (DL) reception timings corresponding to different TRPs.

In a fifth aspect, an embodiment of the present application provides a UE, including a processor and a transmitter, wherein the processor is configured to call and run program instructions stored in a memory, to cooperate with the transmitter to execute the method of any of the first aspect and the third aspect.

In a sixth aspect, an embodiment of the present application provides a TRP, including a processor and a transmitter, wherein the processor is configured to call and run program instructions stored in a memory, to cooperate with the transmitter to execute the method of any of the second aspect and the fourth aspect.

In a seventh aspect, an embodiment of the present application provides a computer readable storage medium provided for storing a computer program, which enables a computer to execute the method of any of the first to the fourth aspects.

In an eighth aspect, an embodiment of the present application provides a computer program product, which includes computer program instructions enabling a computer to execute the method of any of the first to the fourth aspects.

In a ninth aspect, an embodiment of the present application provides a computer program, when running on a computer, enabling the computer to execute the method of any of the first to the fourth aspects.

DESCRIPTION OF DRAWINGS

In order to more clearly illustrate the embodiments of the present application or related art, the following figures that will be described in the embodiments are briefly introduced. It is obvious that the drawings are merely some embodiments of the present application, a person having ordinary skill in this field can obtain other figures according to these figures without paying the premise.

FIG. 1 is a schematic diagram illustrating a multi-TRP scenario.

FIG. 2 is a schematic diagram illustrating distances from different TRPs in a multi-TRP scenario.

FIG. 3 is a schematic diagram illustrating a solution to avoid UL transmission overlapping in a multi-TRP scenario according to the present application.

FIG. 4 is a schematic diagram illustrating UL transmission overlapping that is not avoided even if the solution in FIG. 3 is applied.

FIG. 5 is a schematic diagram illustrating another solution to avoid UL transmission overlapping in a multi-TRP scenario according to the present application.

FIG. 6 is a schematic block diagram illustrating a communication network system according to an embodiment of the present application.

FIG. 7 is a flowchart of a method of reporting timing information in multi-TRP scenario according to a first embodiment of the present application.

FIG. 8 is a schematic diagram illustrating a first example of TA reporting in multi-TRP scenario according to an embodiment of the present application.

FIG. 9 is a schematic diagram illustrating a second example of TA reporting in multi-TRP scenario according to an embodiment of the present application.

FIG. 10 is a schematic diagram illustrating a third example of TA reporting in multi-TRP scenario according to an embodiment of the present application.

FIG. 11 is a schematic diagram illustrating a fourth example of TA reporting in multi-TRP scenario according to an embodiment of the present application.

FIG. 12 is a schematic diagram illustrating a first example of TA reporting in multi-TRP scenario (a) with a time difference less than processing time and (b) with a time difference greater than processing time according to an embodiment of the present application.

FIG. 13 is a schematic diagram illustrating a second example of TA reporting in multi-TRP scenario (a) with a time difference less than processing time and (b) with a time difference greater than processing time according to an embodiment of the present application.

FIG. 14 is a schematic diagram illustrating a third example of TA reporting in multi-TRP scenario (a) with a time difference less than processing time and (b) with a time difference greater than processing time according to an embodiment of the present application.

FIG. 15 is a schematic diagram illustrating a fourth example of TA reporting in multi-TRP scenario (a) with a time difference less than processing time and (b) with a time difference greater than processing time according to an embodiment of the present application.

FIG. 16 is a flowchart of a method of timing information indication in multi-TRP scenario according to a second embodiment of the present application.

FIG. 17 is a flowchart of a method of reporting timing information in multi-TRP scenario according to a third embodiment of the present application.

FIG. 18 is a schematic diagram illustrating a first example of DL reception timing reporting in multi-TRP scenario according to an embodiment of the present application.

FIG. 19 is a schematic diagram illustrating a second example of DL reception timing reporting in multi-TRP scenario according to an embodiment of the present application.

FIG. 20 is a schematic diagram illustrating a third example of DL reception timing reporting in multi-TRP scenario according to an embodiment of the present application.

FIG. 21 is a schematic diagram illustrating a fourth example of DL reception timing reporting in multi-TRP scenario according to an embodiment of the present application.

FIG. 22 is a schematic diagram illustrating a first example of DL reception timing reporting in multi-TRP scenario (a) with a time difference less than processing time and (b) with a time difference greater than processing time according to an embodiment of the present application.

FIG. 23 is a schematic diagram illustrating a second example of DL reception timing reporting in multi-TRP scenario (a) with a time difference less than processing time and (b) with a time difference greater than processing time according to an embodiment of the present application.

FIG. 24 is a schematic diagram illustrating a third example of DL reception timing reporting in multi-TRP scenario (a) with a time difference less than processing time and (b) with a time difference greater than processing time according to an embodiment of the present application.

FIG. 25 is a schematic diagram illustrating a fourth example of DL reception timing reporting in multi-TRP scenario (a) with a time difference less than processing time and (b) with a time difference greater than processing time according to an embodiment of the present application.

FIG. 26 is a flowchart of a method of timing information indication in multi-TRP scenario according to a fourth embodiment of the present application.

DETAILED DESCRIPTION OF EMBODIMENTS

Embodiments of the disclosure are described in detail with the technical matters, structural features, achieved objects, and effects with reference to the accompanying drawings as follows. Specifically, the terminologies in the embodiments of the present application are merely for describing the purpose of the certain embodiment, but not to limit the disclosure.

In 3GPP RAN1#110 meeting, some companies propose a method of scheduling constraints in time domain to avoid UL transmission overlapping. For example, as shown in FIG. 3, UL1 and UL2 are scheduled by network in two consecutive time units respectively. After a UE transmits UL1 with TA1, a UE starts to transmit UL2 with TA2. If TA2 is larger than TA1, the starting of UL2 transmission overlaps with the duration of UL1. The overlapping time can be calculated by the difference between the two TAs. However, for multi-TRP with a non-idea backhaul, one of TRPs only knows its own TA but cannot know the TA corresponding to the other TRP. Nevertheless, a UE can know both two TAs corresponding to different TRPs. In the present application, a UE reports the TA corresponding to a TRP to the other TRP such that TRPs can calculate the overlapping time and schedule UL resources properly to avoid this. For example, as shown in FIG. 3, if a UE reports TA2 to TRP1, after TRP1 calculates Δt _overlapping and schedules UL1 Δt _overlapping early, UL1 do not overlap with UL2.

On the other hand, for multi-TRP with a non-idea synchronization, the additional error will be introduced for DL Tx, because the DL timing offset may be unfortunately compensated along with propagation delay. The additional error may also result in UL transmission overlapping even if the above-mentioned proper scheduling is adopted. For example, as shown in FIG. 4, the time in TRP2 is Δt _DL, TRP earlier than TRP1. This earlier time Δt _DL, TRP results in overlapping between UL1 and UL2. The overlapping time is Δt _DL, TRP. If TRP2 knows the time, TRP2 can adjust the DL timing to avoid overlapping. However, for multi-TRP with a non-idea backhaul, one of TRPs only knows its own DL timing but cannot know the DL timing corresponding to the other TRP.

In 3GPP RAN1#109-e meeting, some companies present the DL timing offset can be calculated by the difference between two TAs and the difference between two DL reception timings, as shown in FIG. 5. The two DL reception timings from two TRPs can be measured by UE. However, for multi-TRP with a non-idea backhaul, one of TRPs only knows its own TA and DL timing but cannot know the TA and the DL reception timing corresponding to the other TRP. Nevertheless, a UE can know both two TAs and DL reception timings corresponding to different TRPs. In the present application, a UE reports the TA and the DL reception timing corresponding to a TRP to the other TRP such that TRPs can calculate the DL timing offset and schedule DL resources properly to avoid UL transmission overlapping. For example, as shown in FIG. 5, if a UE reports TA2 and Δt _DL, UE to TRP1, after TRP1 calculates Δt _DL, TRP and schedules DL1 Δt _DL, TRP later, UL1 does not overlap with UL2.

The main idea of this disclosure is to provide some solutions to reporting information about a TA and a DL reception timing. A UE can report the information to different TRPs through PUCCH or PUSCH. A TRP can transmit a command to indicate UE to report the information. The report timing should consider the treating information time and preparing UL signal time. The report information can help TRPs to schedule UL transmission better to avoid UL transmission overlapping.

FIG. 6 illustrates that, in some embodiments, one or more user equipments (UEs) 10, a first transmission/reception point (TRP) 20 and a second TRP 30 for wireless communication in a communication network system according to an embodiment of the present application are provided. The communication network system includes the one or more UEs 10, the first TRP 20 and the second TRP 30. The one or more UEs 10 may include a memory 12, a transceiver 13, and a processor 11 coupled to the memory 12 and the transceiver 13. The first TRP 20 may include a memory 22, a transceiver 23, and a processor 21 coupled to the memory 22 and the transceiver 23. The second TRP 30 may include a memory 32, a transceiver 33, and a processor 31 coupled to the memory 32 and the transceiver 33. The

processor

11 or 21 or 31 may be configured to implement proposed functions, procedures and/or methods described in this description. Layers of radio interface protocol may be implemented in the

processor

11 or 21 or 31. The

memory

12 or 22 or 32 is operatively coupled with the

processor

11 or 21 or 31 and stores a variety of information to operate the

processor

11 or 21 or 31. The

transceiver

13 or 23 or 33 is operatively coupled with the

processor

11 or 21 or 31, and the

transceiver

13 or 23 or 33 transmits and/or receives a radio signal.

The

processor

11 or 21 or 31 may include application-specific integrated circuit (ASIC) , other chipset, logic circuit and/or data processing device. The

memory

12 or 22 or 32 may include read-only memory (ROM) , random access memory (RAM) , flash memory, memory card, storage medium and/or other storage device. The

transceiver

13 or 23 or 33 may include baseband circuitry to process radio frequency signals. When the embodiments are implemented in software, the techniques described herein can be implemented with modules (e.g., procedures, functions, and so on) that perform the functions described herein. The modules can be stored in the

memory

12 or 22 or 32 and executed by the

processor

11 or 21 or 31. The

memory

12 or 22 or 32 can be implemented within the

processor

11 or 21 or 31 or external to the

processor

11 or 21 or 31 in which case those can be communicatively coupled to the

processor

11 or 21 or 31 via various means as is known in the art.

FIG. 7 is a flowchart of a method of reporting timing information in multi-TRP scenario according to a first embodiment of the present application. Rreferring to FIG. 7 in conjunction with FIG. 6, the method 100 includes the following. In Step 110, the UE reports information to a TRP through physical uplink control channel (PUCCH) or physical uplink shared channel (PUSCH) , wherein the information is at least about timing advance (TA) . The TRP receives this information and schedule UL transmission based on this information. For instance, the information is at least about the TA corresponds to a TRP, and the information is reported to the other TRP. With this method, the timing information (i.e., the TA) is reported to TRP (s) by the UE. The report information can help TRPs to schedule UL transmission better to avoid UL transmission overlapping.

In some embodiments, in the case of reporting the information through PUCCH, the reporting step includes: reporting the information by using PUCCH resources, wherein the PUCCH resources are periodic. Further, the reporting step may include: reporting an old one of the information before the time the UE receives a timing advance command (TAC) or the information is updated; and reporting a new one of the information after the time the UE receives the TAC or the information is updated.

In some embodiments, the reporting step includes: reporting the information when the information is updated. In the case of reporting the information through PUCCH, the reporting step includes: reporting the information at a time point, which is a nearest time after the UE receives a TAC or the information is updated, and at the time point there is a PUCCH resource. In the case of reporting the information through PUSCH, the reporting step includes: reporting the information by using a PUSCH scheduled after a scheduling request (SR) . Further, the reporting step may include: transmitting the SR at a time point, which is a nearest time after the time the UE receives a TAC or the information is updated, and at the time point there is a PUCCH; monitoring an uplink grant or scheduling after transmitting the SR; and reporting the information carried on the PUSCH indicated by the uplink grant. Further, the reporting step may include: reporting the information at a time point after the UE receives a TAC or the information is updated, and at the time point there is a PUSCH resource.

In some embodiments, the reporting step includes: if a time difference between a TAC updating the information and a UL signal for carrying or scheduling the information is larger than total time of treating the TAC and preparing the UL signal, reporting the information through the UL signal. Further, if the time difference between the TAC updating the information and the UL signal for carrying or scheduling the information is less than the total time of treating the TAC and preparing the UL signal, the information is not reported through the UL signal. In some embodiments, an absolute TA is reported by the UE, or a difference between two absolute TAs corresponding to different TRPs is reported by the UE, or a relative TA is reported by the UE.

In an embodiment, a report about a TA is proposed. A UE can report information about a TA corresponding to a TRP to the other TRP through PUCCH or PUSCH.

In a possible implementation, a UE reports a TA corresponding to a TRP to the other TRP periodically through PUCCH. As shown in FIG. 8, a UE is configured specific periodic PUCCH resources for reporting TA. At time t _offset1, t _offset1+T ₁, t _offset1+2T ₁, …, a UE reports TA2 to TRP1 periodically. At time t _offset2, t _offset2+T ₂, t _offset2+2T ₂, …, a UE reports TA1 to TRP2 periodically. At time t _TAC1, a UE receives TAC1, which updates TA1. Before time t _TAC1 (e.g., t _offset2, t _offset2+T ₂) , a UE reports old TA1 to TRP2. After time t _TAC1 (e.g., t _offset2+2T ₂) , a UE reports new TA1 to TRP2. At time t _TAC2, a UE receives TAC2, which updates TA2. Before time t _TAC2 (e.g., t _offset1) , a UE reports old TA2 to TRP1. After time t _TAC2 (e.g., t _offset1+T ₁, t _offset1+2T ₁) , a UE reports new TA2 to TRP1.

In a possible implementation, a UE reports a TA corresponding to a TRP to the other TRP through PUCCH when the TA is updated. As shown in FIG. 9, a UE is configured specific periodic PUCCH resources for reporting TA. At time t _TAC1, a UE receives TAC1 which updates TA1. Then the UE reports TA1 to TRP2 at time t _offset2+2T ₂, which is the nearest time after t _TAC1 and at which there is a PUCCH resource related to TRP2. While at time t _offset2 and t _offset2+T ₂, there are PUCCH resources, which can be utilized to transmit TA1, but TA1 is not updated, so a UE does not report TA1 to TRP2. At time t _TAC2, a UE receives TAC2, which updates TA2. Then a UE reports TA2 to TRP1 at time t _offset1+T ₁, which is the nearest time after t _TAC2 and at which there is a PUCCH resource related to TRP1. While at time t _offset1 and t _offset1+2T ₁, there are PUCCH resources, which can be utilized to transmit TA2, but TA2 is not updated, so a UE does not report TA2 to TRP1. This mechanism can save UL resources.

In a possible implementation, a UE reports a TA corresponding to a TRP to the other TRP through PUSCH. As shown in FIG. 10, a UE is configured specific SR resources for requesting UL resources to report a TA. At time t _TAC1, a UE receives TAC1 which updates TA1. The UE transmits SR2 to TRP2 for requesting PUSCH resources at the time t _offset2+2T ₂ which is the nearest time after t _TAC1 and at which there is a PUCCH resource related to TRP2. After the UE receives UL grant 2, the UE reports TA1 to TRP2 carried by PUSCH. At time t _TAC2, a UE receives TAC2 which updates TA2. The UE transmits SR1 to TRP1 for requesting PUSCH resources at the time t _offset1+T ₁ which is the nearest time after t _TAC2 and at which there is a PUCCH resource related to TRP1. After the UE receives UL grant 1, the UE reports TA2 to TRP1 carried by PUSCH.

In a possible implementation, a UE reports a TA corresponding to a TRP to the other TRP through PUSCH. As shown in FIG. 11, at time t _TAC1, a UE receives TAC1 which updates TA1. If there is PUSCH resource transmitted to TRP2 at time t _offset2 which is after time t _TAC1, the UE reports TA1 to TRP2 carried by PUSCH. At time t _TAC2, a UE receives TAC2 which updates TA2. If there is PUSCH resource transmitted to TRP1 at time t _offset1 which is after time t _TAC2, the UE reports TA2 to TRP1 carried by PUSCH.

In an embodiment, the restriction of report time for information about a TA is proposed. If time difference between a TAC updating a TA and a UL signal for carrying or scheduling the TA is larger than the total time of treating this TAC and preparing this UL signal, a UE reports information about the TA corresponding to a TRP to the other TRP through this UL signal. The time of treating a TAC and preparing a UL signal can be pre-defined or dependent on UE capability.

In a possible implementation, if time difference between a TAC updates a TA and a PUCCH carrying the TA is less than the total time of treating this TAC and preparing this PUCCH, a UE reports an old TA corresponding to a TRP to the other TRP through this PUCCH. For example, as shown in FIG. 12 (a) , if Δt ₁ is less than the total time of treating TAC2 and preparing PUCCH, a UE reports old TA2 to TRP1 through PUCCH at time t _offset1+T ₁ in spite of TA2 updated by TAC2. However, the UE can report new TA2 at time t _offset1+2T ₁ if time difference between TAC2 and the next PUCCH is larger than the total time of treating TAC and preparing PUCCH. If time difference between a TAC updating a TA and a PUCCH carrying the TA is larger than the total time of treating TAC and preparing PUCCH, a UE reports a new TA corresponding to a TRP to the other TRP through this PUCCH. For example, as shown in FIG. 12 (b) , if Δt ₁ is larger than the total time of treating TAC2 and preparing PUCCH, a UE reports new TA2 to TRP1 through PUCCH at time t _offset1+T ₁.

In a possible implementation, if time difference between a TAC updating a TA and a PUCCH is less than the total time of treating this TAC and preparing this PUCCH, a UE does not report a TA corresponding to a TRP to the other TRP. For example, as shown in FIG. 13 (a) , if Δt ₁ is less than the total time of treating TAC2 and preparing PUCCH, a UE does not report TA2 to TRP1 at time t _offset1+T ₁ in spite of TA2 updated by TAC2. However, the UE can report TA2 at time t _offset1+2T ₁ if time difference between TAC2 and the next PUCCH is larger than the total time of treating TAC and preparing PUCCH. If time difference between a TAC updating a TA and a PUCCH is larger than the total time of treating this TAC and preparing this PUCCH, a UE reports a TA corresponding to a TRP to the other TRP through this PUCCH. For example, as shown in FIG. 13 (b) , if Δt ₁ is larger than the total time of treating TAC2 and preparing PUCCH, a UE reports TA2 to TRP1 at time t _offset1+T ₁ through PUCCH.

In a possible implementation, if time difference between a TAC updating a TA and a PUCCH for carrying a PUSCH SR is less than the total time of treating this TAC and preparing this PUCCH, a UE does not transmit SR and does not report a TA. For example, as shown in FIG. 14 (a) , if Δt ₁ is less than the total time of treating TAC2 and preparing PUCCH, a UE does not transmit SR1 to TRP1 at time t _offset1+T ₁ in spite of TA2 updated by TAC2. However, the UE can transmit SR1 at time t _offset1+2T ₁ if time difference between TAC2 and the next PUCCH is larger than the total time of treating TAC and preparing PUCCH. If time difference between TAC updating a TA and PUCCH for carrying a PUSCH SR is larger than the total time of treating this TAC and preparing this PUCCH, a UE transmits SR through this PUCCH. For example, as shown in FIG. 14 (b) , if Δt ₁ is larger than the total time of treating TAC2 and preparing PUCCH, a UE transmits SR1 to TRP1 through PUCCH at time t _offset1+T ₁. After the UE receives UL grant 1, the UE reports TA2 to TRP1 carried by PUSCH.

In a possible implementation, if time difference between a TAC updating a TA and a PUSCH is less than the total time of treating this TAC and preparing this PUSCH, a UE transmits PUSCH but does not report a TA. For example, as shown in FIG. 15 (a) , if Δt ₁ is less than the total time of treating TAC2 and preparing PUSCH, a UE transmits PUSCH but does not report TA2 at time t _offset1 in spite of TA2 updated by TAC2. However, the UE can report TA2 at time t _offset2 if time difference between TAC2 and the next PUSCH is larger than the total time of treating TAC and preparing PUSCH. If time difference between TAC updating a TA and PUSCH for carrying the TA is larger than the total time of treating this TAC and preparing this PUSCH, a UE reports TA2 through this PUSCH. For example, as shown in FIG. 15 (b) , if Δt ₁ is larger than the total time of treating TAC2 and preparing PUSCH, a UE reports TA2 to TRP1 through PUSCH at time t _offset1.

FIG. 16 is a flowchart of a method of timing information indication in multi-TRP scenario according to a second embodiment of the present application. Rreferring to FIG. 16 in conjunction with FIG. 6, the method 200 includes the following. In Step 210, by transmitting a signaling to a user equipment (UE) , a TRP informs the UE to report information at least about timing advance (TA) . That is, upon reception of the signaling from the TRP, the UE reports the information. For instance, the information is at least about the TA corresponding to the other TRP. The signaling is used to inform the UE to report the information to the TRP. This facilitates the reporting of timing information (i.e., the TA) . With this method, the report information can help TRPs to schedule UL transmission better to avoid UL transmission overlapping.

In some embodiments, the method further includes: flushing a timer in the TRP when the TRP receives the information from the UE; and performing the informing step when the timer expires.

In some embodiments, a field in a downlink (DL) downlink control information (DCI) is used to inform whether the UE reports the information through physical uplink control channel (PUCCH) . Further, the information is multiplexing with hybrid automatic repeat request-acknowledgement (HARQ-ACK) information. In some embodiments, a field in a DCI is used to inform whether the UE reports the information through physical uplink shared channel (PUSCH) . Further, the information is multiplexing with UL data. In some embodiments, a field in a DL/UL DCI is used, in which one or more bits in the field are used to inform whether the UE reports the information and one ore more bits in the field are used to indicate a PUCCH resource.

In some embodiments, a special DL DCI is used to inform whether the UE reports the information, and wherein the special DL DCI does not schedule PDSCH such that the UE does not feed back HARQ-ACK in PUCCH indicated by the special DL DCI. In some embodiments, a special UL DCI is used to inform whether the UE reports the information, and the information is reported through PUSCH whose frequency resource allocation and time resource allocation is indicated by the special UL DCI. In some embodiments, a medium access control (MAC) control element (CE) is used to inform the UE to report the information. Further, the MAC CE includes a field with at least one of time offset information or PUCCH resource information.

In some embodiments, the TRP receives an absolute TA reported by the UE, or the TRP receives a difference between two absolute TAs corresponding to different TRPs reported by the UE, or the TRP receives a relative TA reported by the UE.

In an embodiment, a timer related to TA at TRP side is proposed. A TRP maintains a timer related to TA which corresponds to the other TRP and is reported by a UE. When a TRP receives TA corresponding to the other TRP, the TRP flushes the timer immediately. When the timer is overtime, the TRP transmits a command to UE to indicate UE to report TA corresponding to the other TRP.

In a possible implementation, a new field (X bits) is appended in a DL DCI (e.g., DCI format 1_1, DCI format 1_2) as a command to indicate whether a UE reports a TA through PUCCH. For example, assuming X = 1, if the timer in the first TRP is overtime, the first TRP transmits a DL DCI to a UE where the command is ‘1’ . When a UE receives a DL DCI from the first TRP where the command is ‘1’ , the UE reports a TA corresponding to the second TRP to the first TRP through PUCCH which is indicated by the PUCCH resource indicator field in the DL DCI. In this PUCCH, the TA is multiplexing with HARQ-ACK information which is an acknowledgement to PDSCH scheduling by the DL DCI. When a UE receives a DL DCI from the first TRP where the command is ‘0’ , the UE does not report a TA.

In a possible implementation, a new field (X bits) is appended in a UL DCI (e.g., DCI format 0_1, DCI format 0_2) as a command to indicate whether a UE reports a TA through PUSCH. For example, assuming X = 1, if the timer in the first TRP is overtime, the first TRP transmits a UL DCI to a UE where the command is ‘1’ . When a UE receives a UL DCI from the first TRP where the command is ‘1’ , the UE reports a TA corresponding to the second TRP to the first TRP through PUSCH whose frequency resource allocation and time resource allocation is indicated by the UL DCI. In this PUSCH, the TA is multiplexing with UL data. When a UE receives a UL DCI from the first TRP where the command is ‘0’ , the UE does not report a TA.

In a possible implementation, a new field (X bits) is appended in a DL/UL DCI as a command where the former X ₁ bits is used to indicate whether a UE reports a TA and the latter (X-X ₁) bits is used to indicate which PUCCH resource for TA reporting. For example, assuming X = 4 and X ₁ = 1, if the timer in the first TRP is overtime, the first TRP transmits a DL/UL DCI to a UE where the command is ‘1000’ . When a UE receives a DL/UL DCI from the first TRP where the command is ‘1000’ , the UE reports a TA corresponding to the second TRP to the first TRP through the first PUCCH resource. The PUCCH is located at the Nth time units after UE receives DL/UL DCI. The N can be predefined or dependent on the UE capability. When a UE receives a DL/UL DCI from the first TRP where the command is ‘0000’ , the UE does not report a TA.

In a possible implementation, a special DL DCI serves as a command used to indicate whether a UE reports a TA through PUCCH. In this special DL DCI, the HRAQ process number field, the redundancy version field, the modulation and coding scheme field, and/or the frequency domain resource assignment field are set to be all ‘0’s , all ’ 0’s , all ‘1’s , and/or all’ 0’s , respectively. Meanwhile, this specific DL DCI is scrambled by specific RNTI. This special DL DCI does not schedule PDSCH such that a UE does not feedback HARQ-ACK in the PUCCH indicated by this DL DCI. For example, if the timer in the first TRP is overtime, the first TRP transmits this special DL DCI to a UE. When a UE receives the special DL DCI from the first TRP, the UE reports a TA corresponding to the second TRP to the first TRP through PUCCH, which is indicated by the PUCCH resource indicator field in the DL DCI. This PUCCH only carries TA.

In a possible implementation, a special UL DCI serves as a command used to indicate whether a UE reports a TA through PUSCH. In this special UL DCI, the HRAQ process number field, the redundancy version field, and/or the modulation and coding scheme field are set to be all ‘0’s , all ’ 0’s , and/or all ‘1’s , respectively. Meanwhile, this specific UL DCI is scrambled by specific RNTI. For example, if the timer in the first TRP is overtime, the first TRP transmits this special UL DCI to a UE. When a UE receives the special UL DCI from the first TRP, the UE reports a TA corresponding to the second TRP to the first TRP through PUSCH whose frequency resource allocation and time resource allocation is indicated by this special UL DCI. This PUSCH only carries TA information.

In a possible implementation, a MAC CE as a command to indicate whether a UE reports a TA through PUCCH. In this MAC CE, there is/are a time offset indicator field and/or a PUCCH resource indicator field. The time offset indicator field indicates when a UE can report a TA. The PUCCH resource indicator field indicates which resource can be used for reporting TA. Meanwhile, network allocates a new LCID for this MAC CE.

In an embodiment, the content of report information about TA is proposed.

In a possible implementation, a UE reports an absolute TA corresponding to a TRP to the other TRP. If the absolute TA1 maintained by a UE is N _TA1, the UE reports M _TA to TRP2 according to M _TA1 = N _TA /16 /64 ·2 ^μ for SCS of 2 ^μ ·15 kHz. TRP2 obtains the absolute TA1 according to N _TA1 = M _TA ·16 ·64 /2 ^μ. If the report is carried by PUCCH, 12 bits is proposed to bear M _TA1 = 0, 1, 2, …, 4095. If the report is carried PUSCH, a MAC CE at least with the M _TA field is proposed.

In a possible implementation, a UE reports the difference of two absolute TAs corresponding to two TRPs to a TRP. If the absolute TA1 and absolute TA2 maintained by a UE are N _TA1 and N _TA2, the UE reports M _TA to TRP2 according to M _TA = (N _TA1 -N _TA2) /16 /64 ·2 ^μ for SCS of 2 ^μ ·15 kHz. TRP2 obtains the absolute TA1 according to N _TA1 = N _TA2 + M _TA ·16 ·64 /2 ^μ for SCS of 2 ^μ ·15 kHz. To bear M _TA = 0, 1, 2, …, 4095, 12 bits is needed. If the report is carried by PUCCH, 12 bits is proposed to bear M _TA = 0, 1, 2, …, 4095. If the report is carried PUSCH, a MAC CE at least with the M _TA field is proposed.

In a possible implementation, a UE reports a relative TA corresponding to a TRP to the other TRP. When a UE receives a relative TAC1 carrying T _A, 1 from TRP1, the UE directly reports M _TA = T _A, 1 to TRP2. TRP2 obtains the new absolute TA1 according to N _{TA1_new} = N _{TA1_old} + (T _A, 1 -31) ·16 ·64 /2 ^μ for SCS of 2 ^μ ·15 kHz where N _{TA1_old} is the old absolute TA1 maintained by TRP2. To bear M _TA = 0, 1, 2, …, 63, 6 bits is needed. If the report is carried by PUCCH, 6 bits is proposed to bear M _TA = 0, 1, 2, …, 63. If the report is carried PUSCH, a MAC CE at least with the M _TA1 field is proposed.

FIG. 17 is a flowchart of a method of reporting timing information in multi-TRP scenario according to a third embodiment of the present application. Rreferring to FIG. 17 in conjunction with FIG. 6, the method 300 includes the following. In Step 310, the UE reports information through physical uplink control channel (PUCCH) or physical uplink shared channel (PUSCH) , wherein the information is at least about a difference between two downlink (DL) reception timings corresponding to a first TRP and a second TRP. TRP (s) (e.g., the first TRP and/or the second TRP) receives this information and schedule UL transmission based on this information. With this method, the timing information (i.e., the difference between the two DL reception timings) corresponding to two TRPs is reported by the UE.The report information can help TRPs to schedule UL transmission better to avoid UL transmission overlapping.

In some embodiments, in the case of reporting the information through PUCCH, the reporting step includes: reporting the information by using configured PUCCH resources related to the first TRP; or reporting the information by using configured PUCCH resources related to the second TRP. In some embodiments, the reporting step includes: reporting an old one of the information before the information has a change; and reporting a new one of the information after the information has a change.

In some embodiments, the reporting step includes: reporting the information when the information has a change. In the case of reporting the information through PUCCH, the reporting step includes: reporting the information at a time point, which is a nearest time after the information has a change, and at the time point there is a PUCCH resource. In the case of reporting the information through PUSCH, the reporting step includes: reporting the information by using a PUSCH scheduled after a scheduling request (SR) . Further, the reporting step may include: transmitting the SR at a time point, which is a nearest time after the time the information has a change, and at the time point there is a PUCCH; monitoring an uplink grant or scheduling after transmitting the SR; and reporting the information carried on the PUSCH indicated by the uplink grant. Further, the reporting step may include: reporting the information after the time the information has a change, and after the time there is a PUSCH resource avaliable for the reporting.

In some embodiments, the reporting step includes: if a time difference between the time the information has a change and a UL signal for carrying or scheduling the information is larger than total time of preparing the UL signal, reporting the information through the UL signal. Further, if the time difference between the time the information has a change and the UL signal for carrying or scheduling the information is less than the total time of preparing the UL signal, the information is not reported through the UL signal. In some embodiments, the information reported by the UE adopts granularity of timing advance (TA) .

In an embodiment, a report about the difference between two DL reception timings (Δt _DL, UE) is proposed. A UE can report information about Δt _DL, UE through PUCCH or PUSCH.

In a possible implementation, a UE reports Δt _DL, UE periodically through PUCCH. As shown in FIG. 18, a UE is configured specific periodic PUCCH resources for reporting Δt _DL, UE. At time t _offset1, t _offset1+T ₁, t _offset1+2T ₁, …, a UE reports Δt _DL, UE to TRP1 periodically. At time t _offset2, t _offset2+T ₂, t _offset2+2T ₂, …, a UE reports Δt _DL, UE to TRP2 periodically. At time t _DL1, a UE realizes that Δt _DL, UE has a change by measuring DL signals/channels from different TRPs. Before time t _DL1 (e.g., t _offset1 or t _offset2) , a UE reports old Δt _DL, UE to TRP1 or TRP2, respectively. After time t _DL1 (e.g., t _offset1+T ₁ , t _offset1+2T ₁ or t _offset2+T ₂ , t _offset2+2T ₂) , a UE reports new Δt _DL, UE to TRP1 or TRP2, respectively.

In a possible implementation, a UE reports Δt _DL, UE through PUCCH only when Δt _DL, UE is changed. As shown in FIG. 19, a UE is configured specific periodic PUCCH resources for reporting Δt _DL, UE. At time t _DL1, a UE realizes that Δt _DL, UE has a change by measuring DL signals/channels from different TRPs. Then the UE reports Δt _DL, UE to TRP1 or TRP2 at time t _offset1+T ₁ or t _offset2+T ₂ which are the nearest time after t _DL1 and at which there is a PUCCH resource related to TRP1 or TRP2, respectively. While at time t _offset1+2T ₁ or t _offset2+2T ₂, there are PUCCH resources which can be utilized to transmit Δt _DL, UE, but Δt _DL, UE is not changed, so a UE does not report Δt _DL, UE to TRP1 or TRP2, respectively. This mechanism can save UL resources.

In a possible implementation, a UE reports Δt _DL, UE through PUSCH. As shown in FIG. 20, a UE is configured specific SR resources for requesting UL resources to report Δt _DL, UE. At time t _DL1, a UE realize that Δt _DL, UE have a change by measuring DL signals/channels from different TRPs. The UE transmits SR1 or SR2 to TRP1 or TRP2 for requesting PUSCH resources at the time t _offset1+T ₁ or t _offset2+T ₂ which is the nearest time after t _DL1 and at which there is a PUCCH resource related to TRP1 or TRP2, respectively. After the UE receives UL grant 1 or UL grant 2, the UE reports Δt _DL, UE to TRP1 or TRP2 carried by PUSCH, respectively.

In a possible implementation, a UE reports Δt _DL, UE through PUSCH. As shown in FIG. 21, at time t _DL1, a UE realizes that Δt _DL, UE has a change by measuring DL signals/channels from different TRPs. If there is PUSCH resource transmitted to TRP2 at time t _offset2 which is after time t _DL1, the UE reports Δt _DL, UE to TRP2 carried by PUSCH. If there is PUSCH resource transmitted to TRP1 at time t _offset1 which is after time t _DL1, the UE reports Δt _DL, UE to TRP1 carried by PUSCH.

In an embodiment, the restriction of report time for information about a DL reception timing is proposed. If time difference between Δt _DL, UE change and a UL signal for carrying or scheduling Δt _DL, UE is larger than the total time of preparing this UL signal, a UE reports Δt _DL, UE to TRPs, respectively. The time of preparing a UL signal can be pre-defined or dependent on UE capability.

In a possible implementation, if time difference between Δt _DL, UE change and a PUCCH carrying Δt _DL, UE is less than the time of preparing this PUCCH, a UE reports old Δt _DL, UE through this PUCCH to TRPs. For example, as shown in FIG. 22 (a) , if Δt ₁ is less than the time of preparing PUCCH, a UE reports old Δt _DL, UE to TRP1 through this PUCCH at time t _offset1+T ₁ in spite of Δt _DL, UE change. However, the UE can report new Δt _DL, UE at time t _offset1+2T ₁ if time difference between Δt ₁ and the next PUCCH is larger than the time of preparing PUCCH. If time difference between Δt _DL, UE change and a PUCCH carrying Δt _DL, UE is larger than the time of preparing this PUCCH, a UE reports a new Δt _DL, UE to two TRPs. For example, as shown in FIG. 22 (b) , if Δt ₁ is larger than the time of preparing PUCCH, a UE reports new Δt _DL, UE to TRP1 through this PUCCH at time t _offset1+T ₁.

In a possible implementation, if time difference between Δt _DL, UE change and a PUCCH is less than the time of preparing PUCCH, a UE does not report Δt _DL, UE to TRPs. For example, as shown in FIG. 23 (a) , if Δt ₁ is less than the time of preparing PUCCH, a UE does not report Δt _DL, UE to TRP1 at time t _offset1+T ₁ in spite of Δt _DL, UE change. However, the UE can report Δt _DL, UE at time t _offset1+2T ₁ if time difference between Δt _DL, UE change and the next PUCCH is larger than the time of preparing PUCCH. If time difference between Δt _DL, UE change and a PUCCH is larger than the time of preparing this PUCCH, a UE reports Δt _DL, UE to TRPs through this PUCCH. For example, as shown in FIG. 23 (b) , if Δt ₁ is larger than the time of preparing this PUCCH, a UE reports Δt _DL, UE to TRP1 at time t _offset1+T ₁ through this PUCCH.

In a possible implementation, if time difference between Δt _DL, UE change and a PUCCH for carrying a PUSCH SR is less than the time of preparing this PUCCH, a UE does not transmit SR and does not report Δt _DL, UE. For example, as shown in FIG. 24 (a) , if Δt ₁ is less than the total time of preparing PUCCH, a UE does not transmit SR1 to TRP1 at time t _offset1+T ₁ in spite of Δt _DL, UE change. However, the UE can transmit SR1 to TRP1 at time t _offset1+2T ₁ if time difference between Δt _DL, UE change and the next PUCCH is larger than the total time of treating TAC and preparing PUCCH. If time difference between Δt _DL, UE change and a PUCCH for carrying a PUSCH SR is larger than the time of preparing this PUCCH, a UE transmits SR through this PUCCH. For example, as shown in FIG. 24 (b) , if Δt ₁ is larger than the time of preparing PUCCH, a UE transmits SR1 to TRP1 through PUCCH at time t _offset1+T ₁. After the UE receives UL grant 1, the UE reports Δt _DL, UE to TRP1 carried by PUSCH.

In a possible implementation, if time difference between Δt _DL, UE change and a PUSCH is less than the time of preparing this PUSCH, a UE transmits PUSCH but does not report Δt _DL, UE. For example, as shown in FIG. 25 (a) , if Δt ₁ is less than the total time of preparing PUSCH, a UE transmits PUSCH to TRP1 and does not report Δt _DL, UE at time t _offset1 in spite of Δt _DL, UE change. However, the UE can report Δt _DL, UE to TRP1 at time t _offset2 if time difference between Δt _DL, UE change and the next PUSCH is larger than the total time of treating TAC and preparing PUSCH. If time difference between Δt _DL, UE change and a PUSCH is larger than the time of preparing this PUSCH, a UE reports Δt _DL, UE through this PUSCH. For example, as shown in FIG. 25 (b) , if Δt ₁ is larger than the time of preparing PUSCH, a UE reports Δt _DL, UE through PUSCH at time t _offset1.

FIG. 26 is a flowchart of a method of timing information indication in multi-TRP scenario according to a fourth embodiment of the present application. Rreferring to FIG. 26 in conjunction with FIG. 6, the method 400 includes the following. In Step 410, by transmitting a signaling to a user equipment (UE) , a TRP informs the UE to report information at least about a difference between two downlink (DL) reception timings corresponding to different TRPs. That is, upon reception of the signaling from the TRP, the UE reports the information. The signaling is used to inform the UE to report the information to the TRP. This facilitates the reporting of timing information (i.e., the difference between the two DL reception timings) . With this method, the report information can help TRPs to schedule UL transmission better to avoid UL transmission overlapping.

In some embodiments, a field in a DL downlink control information (DCI) is used to inform whether the UE reports the information through physical uplink control channel (PUCCH) . Further, the information is multiplexing with hybrid automatic repeat request-acknowledgement (HARQ-ACK) information. In some embodiments, a field in an uplink (UL) DCI is used to inform whether the UE reports the information through physical uplink shared channel (PUSCH) . Further, the information is multiplexing with UL data. In some embodiments, a field in a DL/UL DCI is used, in which one ore more bits in the field are used to inform whether the UE reports the information and one ore more bits in the field are used to indicate which PUCCH resource is used for the reporting.

In some embodiments, a special DL DCI is used to inform whether the UE reports the information, and wherein the special DL DCI does not schedule PDSCH such that the UE does not feed back HARQ-ACK in PUCCH indicated by the special DL DCI. In some embodiments, a special UL DCI is used to inform whether the UE reports the information, and the information is reported through PUSCH whose frequency resource allocation and time resource allocation is indicated by the special UL DCI. In some embodiments, a medium access control (MAC) control element (CE) is used to inform the UE to report the information. Further, the MAC CE includes a field with at least one of a time offset indicator field or a PUCCH resource indicator field.

In some embodiments, the TRP receives the information that adopts granularity of timing advance (TA) .

In an embodiment, a timer related to the difference between two DL reception timings (Δt _DL, UE) at TRP side is proposed. A TRP maintains a timer related to Δt _DL, UE which is reported by a UE. When a TRP receives Δt _DL, UE, the TRP flushes the timer immediately. When the timer is overtime, the TRP transmits a command to UE to indicate UE to report Δt _DL, UE.

In a possible implementation, a new field (X bits) is appended in a DL DCI (e.g., DCI format 1_1, DCI format 1_2) as a command to indicate whether a UE reports Δt _DL, UE through PUCCH. For example, assuming X = 1, if the timer in the first TRP is overtime, the first TRP transmits a DL DCI to a UE where the command is ‘1’ . When a UE receives a DL DCI from the first TRP where the command is ‘1’ , the UE reports Δt _DL, UE to the first TRP through PUCCH which is indicated by the PUCCH resource indicator field in the DL DCI. In this PUCCH, Δt _DL, UE is multiplexing with HARQ-ACK information which is an acknowledgement to PDSCH scheduling by the DL DCI. When a UE receives a DL DCI from the first TRP where the command is ‘0’ , the UE does not report Δt _DL, UE.

In a possible implementation, a new field (X bits) is appended in a UL DCI (e.g., DCI format 0_1, DCI format 0_2) as a command to indicate whether a UE reports Δt _DL, UE through PUSCH. For example, assuming X = 1, if the timer in the first TRP is overtime, the first TRP transmits a UL DCI to a UE where the command is ‘1’ . When a UE receives a UL DCI from the first TRP where the command is ‘1’ , the UE reports Δt _DL, UE to the first TRP through PUSCH whose frequency resource allocation and time resource allocation is indicated by the UL DCI. In this PUSCH, Δt _DL, UE is multiplexing with UL data. When a UE receives a UL DCI from the first TRP where the command is ‘0’ , the UE does not report Δt _DL, UE.

In a possible implementation, a new field (X bits) is appended in a DL/UL DCI as a command where the former X ₁ bits is used to indicate whether a UE reports a TA and the latter (X-X ₁) bits is used to indicate which PUCCH resource for Δt _DL, UE reporting. For example, assuming X = 4 and X ₁ = 1, if the timer in the first TRP is overtime, the first TRP transmits a DL/UL DCI to a UE where the command is ‘1000’ . When a UE receives a DL/UL DCI from the first TRP where the command is ‘1000’ , the UE reports Δt _DL, UE to the first TRP through the first PUCCH resource. The PUCCH is located at the Nth time units after UE receives DL/UL DCI. The N can be predefined or dependent on the UE capability. When a UE receives a DL/UL DCI from the first TRP where the command is ‘0000’ , the UE does not report Δt _DL, UE.

In a possible implementation, a special DL DCI as a command is used to indicate whether a UE reports a TA through PUCCH. In this special DL DCI, the HRAQ process number field, the redundancy version field, the modulation and coding scheme field, and/or the frequency domain resource assignment field are set to be all ‘0’s , all ’ 0’s , all ‘1’s , and/or all’ 0’s , respectively. Meanwhile, this specific DL DCI is scrambled by specific RNTI. This special DL DCI does not schedule PDSCH such that a UE does not feedback HARQ-ACK in the PUCCH indicated by this DL DCI. For example, if the timer in the first TRP is overtime, the first TRP transmits this special DL DCI to a UE. When a UE receives the special DL DCI from the first TRP, the UE reports a TA corresponding to the second TRP to the first TRP through PUCCH, which is indicated by the PUCCH resource indicator field in the DL DCI. This PUCCH only carries TA information.

In a possible implementation, a special UL DCI as a command is used to indicate whether a UE reports Δt _DL, UE through PUSCH. In this special UL DCI, the HRAQ process number field, the redundancy version field, and/or the modulation and coding scheme field are set to be all ‘0’s , all ’ 0’s , and/or all ‘1’s , respectively. Meanwhile, this specific UL DCI is scrambled by specific RNTI. For example, if the timer in the first TRP is overtime, the first TRP transmits this special UL DCI to a UE. When a UE receives the special UL DCI from the first TRP, the UE reports Δt _DL, UE to the first TRP through PUSCH whose frequency resource allocation and time resource allocation is indicated by this special UL DCI. This PUSCH only carries Δt _DL, UE.

In a possible implementation, a MAC CE as a command to indicate whether a UE reports Δt _DL, UE through PUCCH. In this MAC CE, there is/are a time offset indicator field and/or a PUCCH resource indicator field. The time offset indicator field indicates when a UE can report Δt _DL, UE. The PUCCH resource indicator field indicates which resource can be used for reporting Δt _DL, UE. Meanwhile, network allocates a new LCID for this MAC CE.

In an embodiment, an estimation method of report granularity and quantization parameter of the difference between two DL reception timings is proposed. The report granularity can adopt the granularity of TA. The quantization parameter can be determined by a DL timing offset and two TAs.

In current spec, the method of TA adjustment is to adjust the quantization parameter M _TA according to T _TA = M _TA ·16 ·64 /2 ^μ ·T _c for SCS of 2 ^μ ·15 kHz. Therefore, the granularity of the TA adjustment is 16 ·64 /2 ^μ ·T _c. To align with TA, the difference between two DL reception timings corresponding to different TRPs (Δt _DL, UE) should also adopt this granularity. According to the formula in FIG. 5, Δt _DL, UE can be calculated by a DL timing offset and two TAs, where DL timing offset is not larger than the duration time of a CP (T _CP) . The quantization parameter M _CP of a CP can be calculated by M _CP = T _CP /16 /64 ·2 ^μ /T _c, whose values for SCS of 2 ^μ ·15 kHz are shown in Table 1. Therefore, the quantization parameter M _DL, UE of Δt _DL, UE can be (M _TA /2 + M _CP) .

Table 1. The quantization parameters of a cyclic prefix.

Numerology (μ)

SCS (kHz)

M _CP of Normal CP (long)

M _CP of Normal CP (short)

M _CP of Extend CP

0	15	9	10	-
1	30	9	11	-
2	60	9	13	32
3	120	9	17	-
4	240	9	25	-

A UE can obtain Δt _DL, UE by measuring DL signals/channels corresponding to different TRPs. Then, the UE calculates M _DL, UE according to the formula M _DL, UE = Δt _DL, UE /16 /64 ·2 ^μ /T _c, and reports M _DL, UE to TRPs. When TRPs receive M _DL, UE, TRPs obtain Δt _DL, UE according to the formula Δt _DL, UE = M _DL, UE ·16 ·64 /2 ^μ ·T _c. If the report is carried by PUCCH, 11 bits is proposed to bear M _DL, UE = 0, 1, 2, …, 2048. If the report is carried by PUSCH, a MAC CE at least with the M _DL, UE field is proposed.

Commercial interests for some embodiments are as follows. 1. Solving issues in the prior art. 2. Scheduling UL transmission better. 3. Avoiding UL transmission overlapping. 4. Providing a good communication performance. Some embodiments of the present application are used by 5G-NR chipset vendors, V2X communication system development vendors, automakers including cars, trains, trucks, buses, bicycles, moto-bikes, helmets, and etc., drones (unmanned aerial vehicles) , smartphone makers, communication devices for public safety use, AR/VR device maker for example gaming, conference/seminar, education purposes. Some embodiments of the present application are a combination of “techniques/processes” that can be adopted in 3GPP specification to create an end product. Some embodiments of the present application could be adopted in the 5G NR unlicensed band communications. Some embodiments of the present application propose technical mechanisms.

The embodiment of the present application further provides a computer readable storage medium for storing a computer program. The computer readable storage medium enables a computer to execute corresponding processes implemented by the UE/base station (BS) /TRP in each of the methods of the embodiment of the present application. For brevity, details will not be described herein again.

The embodiment of the present application further provides a computer program product including computer program instructions. The computer program product enables a computer to execute corresponding processes implemented by the UE/BS/TRP in each of the methods of the embodiment of the present application. For brevity, details will not be described herein again.

The embodiment of the present application further provides a computer program. The computer program enables a computer to execute corresponding processes implemented by the UE/BS/TRP in each of the methods of the embodiment of the present application. For brevity, details will not be described herein again.

A person of ordinary skill in the art may be aware that, in combination with the examples described in the embodiments disclosed in this specification, units and algorithm steps may be implemented by electronic hardware or a combination of computer software and electronic hardware. Whether the functions are performed by hardware or software depends on particular applications and design constraint conditions of the technical solutions. A person skilled in the art may use different approaches to implement the described functions for each particular application, but it should not be considered that the implementation goes beyond the scope of the present application.

While the present application has been described in connection with what is considered the most practical and preferred embodiments, it is understood that the present application is not limited to the disclosed embodiments but is intended to cover various arrangements made without departing from the scope of the broadest interpretation of the appended claims.

Claims

A method of reporting timing information in multiple transmission-reception point (multi-TRP) scenario, performed by a user equipment (UE) in a network, the method comprising:

reporting information through physical uplink control channel (PUCCH) or physical uplink shared channel (PUSCH) , wherein the information is at least about timing advance (TA) .
The method of claim 1, wherein in the reporting step, the information is at least about the TA corresponds to a TRP, and the information is reported to the other TRP.
The method of claim 1, wherein in the case of reporting the information through PUCCH, the reporting step comprises:

reporting the information by using PUCCH resources, wherein the PUCCH resources are periodic.
The method of claim 3, wherein the reporting step comprises:

reporting an old one of the information before the time the UE receives a timing advance command (TAC) or the information is updated; and

reporting a new one of the information after the time the UE receives the TAC or the information is updated.
The method of claim 1, wherein the reporting step comprises:

reporting the information when the information is updated.
The method of claim 5, wherein in the case of reporting the information through PUCCH, the reporting step comprises:

reporting the information at a time point, which is a nearest time after the UE receives a TAC or the information is updated, and at the time point there is a PUCCH resource.
The method of claim 5, wherein in the case of reporting the information through PUSCH, the reporting step comprises:

reporting the information by using a PUSCH scheduled after a scheduling request (SR) .
The method of claim 7, wherein the reporting step comprises:

transmitting the SR at a time point, which is a nearest time after the time the UE receives a TAC or the information is updated, and at the time point there is a PUCCH;

monitoring an uplink grant or scheduling after transmitting the SR; and

reporting the information carried on the PUSCH indicated by the uplink grant.
The method of claim 5, wherein the reporting step comprises:

reporting the information at a time point after the UE receives a TAC or the information is updated, and at the time point there is a PUSCH resource.
The method of any of claims 1 to 9, wherein the reporting step comprises:

if a time difference between a TAC updating the information and a UL signal for carrying or scheduling the information is larger than total time of treating the TAC and preparing the UL signal, reporting the information through the UL signal.
The method of claim 10, wherein if the time difference between the TAC updating the information and the UL signal for carrying or scheduling the information is less than the total time of treating the TAC and preparing the UL signal, the information is not reported through the UL signal.
The method of claim 1, wherein an absolute TA is reported by the UE, or a difference between two absolute TAs corresponding to different TRPs is reported by the UE, or a relative TA is reported by the UE.
A method of timing information indication in multiple transmission-reception point (multi-TRP) scenario, performed by a TRP in a network, the method comprising:

by transmitting a signaling to a user equipment (UE) , informing the UE to report information at least about timing advance (TA) .
The method of claim 13, wherein the signaling is used to inform the UE to report the information to the TRP, and wherein the information is at least about the TA corresponding to the other TRP.
The method of claim 13, further comprising:

flushing a timer in the TRP when the TRP receives the information from the UE; and

performing the informing step when the timer expires.
The method of claim 13, wherein a field in a downlink (DL) downlink control information (DCI) is used to inform whether the UE reports the information through physical uplink control channel (PUCCH) .
The method of claim 16, wherein the information is multiplexing with hybrid automatic repeat request-acknowledgement (HARQ-ACK) information.
The method of claim 13, wherein a field in a DCI is used to inform whether the UE reports the information through physical uplink shared channel (PUSCH) .
The method of claim 18, wherein the information is multiplexing with UL data.
The method of claim 13, wherein a field in a DL/UL DCI is used, in which one ore more bits in the field are used to inform whether the UE reports the information and one ore more bits in the field are used to indicate a PUCCH resource.
The method of claim 13, wherein a special DL DCI is used to inform whether the UE reports the information, and wherein the special DL DCI does not schedule PDSCH such that the UE does not feed back HARQ-ACK in PUCCH indicated by the special DL DCI.
The method of claim 13, wherein a special UL DCI is used to inform whether the UE reports the information, and the information is reported through PUSCH whose frequency resource allocation and time resource allocation is indicated by the special UL DCI.
The method of claim 13, wherein a medium access control (MAC) control element (CE) is used to inform the UE to report the information.
The method of claim 23, wherein the MAC CE comprises a field with at least one of time offset information or PUCCH resource information.
The method of claim 13, wherein the TRP receives an absolute TA reported by the UE, or the TRP receives a difference between two absolute TAs corresponding to different TRPs reported by the UE, or the TRP receives a relative TA reported by the UE.
A method of reporting timing information in multiple transmission-reception point (multi-TRP) scenario, performed by a user equipment (UE) in a network, the method comprising:

reporting information through physical uplink control channel (PUCCH) or physical uplink shared channel (PUSCH) , wherein the information is at least about a difference between two downlink (DL) reception timings corresponding to a first TRP and a second TRP.
The method of claim 26, wherein in the case of reporting the information through PUCCH, the reporting step comprises:

reporting the information by using configured PUCCH resources related to the first TRP; or

reporting the information by using configured PUCCH resources related to the second TRP.
The method of claim 26, wherein the reporting step comprises:

reporting an old one of the information before the information has a change; and

reporting a new one of the information after the information has a change.
The method of claim 26, wherein the reporting step comprises:

reporting the information when the information has a change.
The method of claim 29, wherein in the case of reporting the information through PUCCH, the reporting step comprises:

reporting the information at a time point, which is a nearest time after the information has a change, and at the time point there is a PUCCH resource.
The method of claim 29, wherein in the case of reporting the information through PUSCH, the reporting step comprises:

reporting the information by using a PUSCH scheduled after a scheduling request (SR) .
The method of claim 31, wherein the reporting step comprises:

transmitting the SR at a time point, which is a nearest time after the time the information has a change, and at the time point there is a PUCCH;

monitoring an uplink grant or scheduling after transmitting the SR; and

reporting the information carried on the PUSCH indicated by the uplink grant.
The method of claim 29, wherein the reporting step comprises:

reporting the information after the time the information has a change, and after the time there is a PUSCH resource avaliable for the reporting.
The method of any of claims 26 to 33, wherein the reporting step comprises:

if a time difference between the time the information has a change and a UL signal for carrying or scheduling the information is larger than total time of preparing the UL signal, reporting the information through the UL signal.
The method of claim 34, wherein if the time difference between the time the information has a change and the UL signal for carrying or scheduling the information is less than the total time of preparing the UL signal, the information is not reported through the UL signal.
The method of claim 26, wherein the information reported by the UE adopts granularity of timing advance (TA) .
A method of timing information indication in multiple transmission-reception point (multi-TRP) scenario, performed by a TRP in a network, the method comprising:

by transmitting a signaling to a user equipment (UE) , informing the UE to report information at least about a difference between two downlink (DL) reception timings corresponding to different TRPs.
The method of claim 37, wherein the signling is used to inform the UE to report the information to the TRP.
The method of claim 37, further comprising:

flushing a timer in the TRP when the TRP receives the information from the UE; and

performing the informing step when the timer expires.
The method of claim 37, wherein a field in a DL downlink control information (DCI) is used to inform whether the UE reports the information through physical uplink control channel (PUCCH) .
The method of claim 40, wherein the information is multiplexing with hybrid automatic repeat request-acknowledgement (HARQ-ACK) information.
The method of claim 37, wherein a field in an uplink (UL) DCI is used to inform whether the UE reports the information through physical uplink shared channel (PUSCH) .
The method of claim 42, wherein the information is multiplexing with UL data.
The method of claim 37, wherein a field in a DL/UL DCI is used, in which one ore more bits in the field are used to inform whether the UE reports the information and one ore more bits in the field are used to indicate which PUCCH resource is used for the reporting.
The method of claim 37, wherein a special DL DCI is used to inform whether the UE reports the information, and wherein the special DL DCI does not schedule PDSCH such that the UE does not feed back HARQ-ACK in PUCCH indicated by the special DL DCI.
The method of claim 37, wherein a special UL DCI is used to inform whether the UE reports the information, and the information is reported through PUSCH whose frequency resource allocation and time resource allocation is indicated by the special UL DCI.
The method of claim 37, wherein a medium access control (MAC) control element (CE) is used to inform the UE to report the information.
The method of claim 47, wherein the MAC CE comprises a field with at least one of a time offset indicator field or a PUCCH resource indicator field.
The method of claim 37, wherein the TRP receives the information that adopts granularity of timing advance (TA) .
A user equipment (UE) , comprising a processor and a transmitter, wherein the processor is configured to call and run program instructions stored in a memory, to cooperate with the transmitter to execute the method of any of claims 1 to 12.
A transmission-reception point (TRP) , comprising a processor and a transmitter, wherein the processor is configured to call and run program instructions stored in a memory, to cooperate with the transmitter to execute the method of any of claims 13 to 25.
A user equipment (UE) , comprising a processor and a transmitter, wherein the processor is configured to call and run program instructions stored in a memory, to cooperate with the transmitter to execute the method of any of claims 26 to 36.
A transmission-reception point (TRP) , comprising a processor and a transmitter, wherein the processor is configured to call and run program instructions stored in a memory, to cooperate with the transmitter to execute the method of any of claims 37 to 49.