WO2021159292A1

WO2021159292A1 - Methods and apparatus of spatial relation switching for nr communication

Info

Publication number: WO2021159292A1
Application number: PCT/CN2020/074812
Authority: WO
Inventors: Zhixun Tang; Tsang-Wei Yu; Hsuan-Li Lin
Original assignee: Mediatek Singapore Pte. Ltd.
Priority date: 2020-02-12
Filing date: 2020-02-12
Publication date: 2021-08-19
Also published as: TWI815083B; CN113259953A; TW202131736A; CN113259953B

Abstract

The configured spatial relation can be QCLed to the source of DL RS, such as SSB or CSI-RS, where the terminology 'QCLed' means associated to in the document below. In this QCLed relation, the active spatial relation switching shall differentiate known and unknown situation. In known condition, when UE receives the spatial relation switching configuration, the UE shall parse this configuration and execute the fine timing tracking on the new configured QCLed RS. After that, the UE shall switch its spatial relation to the new configuration. In unknown condition, besides the above procedure, the UE shall also execute the L1-RSRP measurement after UE parse the spatial relation configuration and before the fine timing tracking. The configured spatial relation can be QCLed to the root source of UL SRS. In this QCLed relation, the active spatial relation switching don' t need to differentiate known and unknown situation. When UE receives the spatial relation switching configuration, the UE shall parse this configuration and switch the spatial relation followed with the configured SRS index. This spatial relation switching shall apply for PUSCH, PUCCH, and SRS. In PUCCH, the MAC based spatial relation switch shall be defined. In PUSCH, spatial relation activation shall only follow the related PUCCH or SRS spatial relation switch procedure. In periodic SRS, the RRC based spatial relation switch shall be defined. In semi-persistent SRS, the MAC based spatial relation switch shall be defined. In aperiodic SRS, the DCI based spatial relation switch shall be defined. The aperiodic SRS should always associate with a known spatial relation.

Description

METHODS AND APPARATUS OF SPATIAL RELATION SWITCHING FOR NR COMMUNICATION

FIELD OF INVENTION

This disclosure relates generally to wireless communications, and, more particularly, to methods and apparatus for the spatial relation switching of NR communications.

BACKGROUND OF THE INVENTION

In 5G new radio, spatial relation is signalling by network to indicate the QCL-type to UE for uplink channels and RSs.

Two kind of spatial relation are defined. {QCL-TypeA, QCL-TypeB, QCL-TypeC} is related to channel statistical character. {QCL-TypeD} is related to spatial Tx parameters which is the parameter related to FR2 only.

The network can indicate the target spatial relation to UE to change the QCL-type by RRC reconfiguration, MAC-CE activation and DCI indication.

However, there are several issues to be addressed, e.g., how to switch the active spatial relation to a new spatial relation.

SUMMARY OF THE INVENTION

This disclosure relates generally to wireless communications, and, more particularly, to methods and apparatus for the active spatial relation switching design of NR communications.

The configured spatial relation can be QCLed to the source of DL RS, such as SSB or CSI-RS, where the terminology ‘QCLed’ means associated to in the document below. In this QCLed relation, the active spatial relation switching shall differentiate known and unknown situation. In known condition, when UE receives the spatial relation switching configuration, the UE shall parse this configuration and execute the fine timing tracking on the new configured QCLed RS. After that, the UE shall switch its spatial relation to the new configuration. In unknown condition, besides the above procedure, the UE shall also execute the L1-RSRP measurement after UE parse the spatial relation configuration and before the fine timing tracking.

The configured spatial relation can be QCLed to the root source of UL SRS. In this QCLed relation, the active spatial relation switching don’t need to differentiate known and unknown situation. When UE receives the spatial relation switching configuration, the UE shall parse this configuration and switch the spatial relation followed with the configured SRS index.

This spatial relation switching shall apply for PUSCH, PUCCH, and SRS. In PUCCH, the MAC based spatial relation switch shall be defined. In PUSCH, spatial relation activation shall only follow the related PUCCH or SRS spatial relation switch procedure. In periodic SRS, the RRC based spatial relation switch shall be defined. In semi-persistent SRS, the MAC based spatial relation switch shall be defined. In aperiodic SRS, the DCI based spatial relation switch shall be defined. The aperiodic SRS should always associate with a known spatial relation.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein:

FIG. 1 shows a wireless communication system according to an embodiment of the disclosure.

FIG. 2 shows an example of spatial relation switching.

FIG. 3 shows examples of uplink QCLed relation source.

FIG. 4 shows an example of spatial relation switching procedure when the configured spatial relation is QCLed to a DL RS.

FIG. 5 shows an example of spatial relation switching procedure when the configured spatial relation is QCLed to a SRS.

FIG. 6 shows an example of PUCCH spatial relation switching.

FIG. 7 shows an example of PUSCH spatial relation switching.

FIG. 8 shows an example of SRS spatial relation switching.

FIG. 9 shows an exemplary block diagram of a UE (a.k.a device) according to an embodiment of the disclosure.

DETAILED DESCRIPTION

Certain terms are used throughout the description and following claims to refer to particular components. As one skilled in the art will appreciate, manufacturers may refer to a component by different names. This document does not intend to distinguish between components that differ in name but not function. In the following description and in the claims, the terms "include" and "comprise" are used in an open-ended fashion, and thus should be interpreted to mean "include, but not limited to ... " . Also, the term "couple" is intended to mean either an indirect or direct electrical connection. Accordingly, if one device is coupled to another device, that connection may be through a direct electrical connection, or through an indirect electrical connection via other devices and connections. The making and using of the embodiments of the disclosure are discussed in detail below. It should be appreciated, however, that the embodiments can be embodied in a wide variety of specific contexts. The specific embodiments discussed are merely illustrative, and do not limit the scope of the disclosure. Some variations of the embodiments are described. Throughout the various views and illustrative embodiments, like reference numbers are used to designate like elements.

The following description is of the best-contemplated mode of carrying out the invention. This description is made for the purpose of illustrating the general principles of the invention and should not be taken in a limiting sense. Note that the 3GPP specifications described herein are used to teach the spirit of the invention, and the invention is not limited thereto.

FIG. 1 shows a wireless communication system 100 according to an embodiment of the disclosure. The system 100 can include a user equipment (UE) 110 and a base station (BS) 120. The system 100 can be a cellular network, and employ the New Radio (NR) technologies and the LTE technologies developed by the 3rd Generation Partnership Project (3GPP) for wireless communications between the UE 110 and the BS 120. The UE 110 can be a mobile phone, a laptop computer, a device carried in a vehicle, and the like. The BS 120 can be an implementation of a gNB specified in NR standards. Accordingly, the UE 110 can communicate with the base station 120 through a wireless communication channel according to communication protocols specified in respective communication standards. Please note that the invention is not limited by this.

In one example, the UE 110 and the base station 120 are configured to deploy carrier aggregation (CA) or dual-connection (DC) techniques to enhance UE’s throughput.

When the system deploy the CA, it could have Master Cell Group (MCG) 130. The MCG 130 includes Pcell 131 and SCell 1 132 to SCell N 133.

When the system deploy the DC, it could have Master Cell Group (MCG) 130 and Secondary Cell Group (SCG) 140. The MCG 130 includes Pcell 131 and SCell 1 132 to SCell N 133. The SCG 140 includes PScell 141 and SCell 1 142 to SCell N 143.

FIG. 2 shows an example of spatial relation switching when the spatial relation is configured to QCLed with a DL RSs, where, the terminology ‘QCLed’ can also be said as associated. At first, the network configured the spatial relation to request the UE to use Tx1 to transmit the signals. The network used the Rx3 to receive the transmission signals. After a while, the network detects UE to use Tx3 better than to use Tx1. Then the network configure the new spatial relation configuration to request the UE switch its Tx beam from Tx1 to Tx3. The network can use its Rx1 to receive the signals from UE.

FIG. 3 shows two examples of spatial relation QCLed source RSs’ definition. In (a) , a PUSCH channel 310 is configured a spatial relation to QCLed with SRS index #0 320, and this SRS #0 320 has already configured to QCLed with a DL SSB #0 330. We call this source of PUSCH channel QCLed relation is DL RS, SSB #0. The DL RS can be SRS or CSI-RS.

In (b) , a PUSCH channel 340 is configured a spatial relation to QCLed with SRS index #0 350, and this SRS #0 350 no other QCLed relation was configured. Basically, this SRS can be configured with ‘beamManagement’ . We call this source of PUSCH channel QCLed relation is UL SRS, SRS #0.

FIG. 4 shows a procedure of spatial relation switching when the configured spatial relation is QCLed to a source DL RS. The known and unknown condition shall be defined.

When the QCLed source is a DL RS, such as SSB or CSI-RS, the configured spatial relation is known if it has been meeting the following conditions:

1. Spatial relation switch is within [X] s of last transmission of the resource for beam reporting/measurement for the target spatial relation, such as X=1.28s

2. The UE has sent at least 1 measurement report for the target spatial relation

3. The spatial relation shall remain detectable during the spatial relation switching period

4. SNR of the RS which the spatial relation is configured is > -3dB

Otherwise, the spatial relation is unknown.

In known condition, when network receives the UE’s measurement reporting, the network may configure the UE to switch to a new spatial relation. When UE receives the spatial relation switch command, the UE only need to decode the command and execute one-shot fine timing tracking. After that, the UE will finish the active spatial relation switch.

In unknown condition, the network may configure the UE to switch to a new spatial relation without any measurement information. When UE receives the spatial relation switch command, the UE need to decode the command. After that, execute Rx beam sweeping to find the best Rx beam and do the one-shot fine timing tracking. After that, the UE will finish the active spatial relation switch.

When the spatial relation is unknown, the UE should execute the L1-RSRP measurement (Rx beam sweeping) to train the downlink spatial domain filter before transmitting the uplink signals with the same spatial domain transmission filter. During the training phase, the UE only has the previous spatial relation information (which UE adopted before receiving the switch command) and also this information is known to network. Thus, UE shall be allowed to be transmitted signals with previous spatial domain transmission filter, but the signal quality cannot be guaranteed before UE finishes the active spatial relation switching.

FIG. 5 shows a procedure of spatial relation switching when the configured spatial relation is QCLed to a source SRS. After some QCLed links, the spatial relation shall be QCLed with SRS with its usage configured as ‘beamManagement’ .

In this case, UE does not need any additional beam sweeping procedure. Thus, the procedure won’t differentiate known and unknown condition when uplink spatial relation is QCLed to a SRS. At first, the network can configure some spatial relation lists to UE 510. Then the network directly configure a new spatial relation with SRS index to UE 520. When UE parses the spatial relation QCLed to a SRS index 530, UE will only follow the same beam with this uplink SRS 540.

FIG. 6 shows a procedure of spatial relation switching for PUCCH. RRC is required at first to configure with up to 8 spatial relations 610. MAC CE activates one of the spatial relation for PUCCH 620. The UE will transmit the PUCCH using a same Rx spatial domain filter as a reception of a SSB or CSI-RS or a transmission of a SRS. Thus, the MAC based active spatial relation switch shall be defined when active spatial relation switches for PUCCH.

As we discussed above, when active spatial relation is configured to switch to a DL RS, the UE requirements will be different for known and unknown case. When active spatial relation is configured to switch to a SRS, we only need to consider MAC CE parsing time.

FIG. 7 shows a procedure of spatial relation switching for PUSCH. PUSCH spatial relation is explicitly demonstrated and follows either the PUCCH or SRS spatial relation depending on the DCI command received, i.e., DCI format 0_0 or 0_1.

When DCI format 0_0 is received, PUSCH always follows the same spatial domain transmission filter as for PUCCH 710. When DCI format 0_1 is configured, the UE shall transmit PUSCH using the same antenna ports as the SRS port (s) in the SRS resource (s) indicated by SRI (s) 730. The indicated SRI in slot n is associated with the most recent transmission of SRS resource identified by the SRI. PUSCH spatial relation activation shall only follow the related PUCCH or SRS spatial relation switch procedure.

FIG. 8 shows a procedure of spatial relation switching for SRS. The SRS resources also can be periodic, semi-persistent, or aperiodic. Periodic SRS is configured by RRC 810. Semi-persistent SRS is activated by MAC-CE 840. Aperiodic SRS is triggered/activated by DCI command 870.

If the SRS is associated with another uplink SRS, UE will directly use the same beam for this uplink SRS. UE does not need the additional Rx beam sweeping time.

When network configures periodic/semi-persistent SRS transmission, if the SRS is associated with the DL RS, the active spatial relation switch shall differentiate between known and unknown condition.

For aperiodic SRS, generally, it could be believed as an urgent sounding behaviour. It means the network doesn’t want additional beam training time and needs this sounding information as soon as possible. The time interval between the DCI command and the aperiodic SRS transmission is a very short time duration. Thus, the aperiodic SRS should always associate with a known spatial relation.

FIG. 9 shows an exemplary block diagram of a UE according to an embodiment of the disclosure. The UE 900 can be configured to implement various embodiments of the disclosure described herein. The UE 900 can include a processor 910, a memory 920, and a radio frequency (RF) module 930 that are coupled together as shown in FIG. 9. In different examples, the UE 900 can be a mobile phone, a tablet computer, a desktop computer, a vehicle carried device, and the like.

The processor 910 can be configured to perform various functions of the UE 120 described above with reference to FIGs. 1-8. The processor 910 can include signal processing circuitry to process received or to be transmitted data according to communication protocols specified in, for example, LTE and NR standards. Additionally, the processor 910 may execute program instructions, for example, stored in the memory 920, to perform functions related with different communication protocols. The processor 910 can be implemented with suitable hardware, software, or a combination thereof. For example, the processor 910 can be implemented with application specific integrated circuits (ASIC) , field programmable gate arrays (FPGA) , and the like, that includes circuitry. The circuitry can be configured to perform various functions of the processor 910.

In one example, the memory 920 can store program instructions that, when executed by the processor 910, cause the processor 910 to perform various functions as described herein. The memory 920 can include a read only memory (ROM) , a random access memory (RAM) , a flash memory, a solid state memory, a hard disk drive, and the like.

The RF module 930 can be configured to receive a digital signal from the processor 510 and accordingly transmit a signal to a base station in a wireless communication network via an antenna 940. In addition, the RF module 930 can be configured to receive a wireless signal from a base station and accordingly generate a digital signal which is provided to the processor 910. The RF module 930 can include digital to analog/analog to digital converters (DAC/ADC) , frequency down/up converters, filters, and amplifiers for reception and transmission operations. For example, the RF module 930 can include converter circuits, filter circuits, amplification circuits, and the like, for processing signals on different carriers or bandwidth parts.

The UE 900 can optionally include other components, such as input and output devices, additional CPU or signal processing circuitry, and the like. Accordingly, the UE 500 may be capable of performing other additional functions, such as executing application programs, and processing alternative communication protocols.

The processes and functions described herein can be implemented as a computer program which, when executed by one or more processors, can cause the one or more processors to perform the respective processes and functions. The computer program may be stored or distributed on a suitable medium, such as an optical storage medium or a solid-state medium supplied together with, or as part of, other hardware. The computer program may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunication systems. For example, the computer program can be obtained and loaded into an apparatus, including obtaining the computer program through physical medium or distributed system, including, for example, from a server connected to the Internet.

The computer program may be accessible from a computer-readable medium providing program instructions for use by or in connection with a computer or any instruction execution system. A computer readable medium may include any apparatus that stores, communicates, propagates, or transports the computer program for use by or in connection with an instruction execution system, apparatus, or device. The computer-readable medium can be magnetic, optical, electronic, electromagnetic, infrared, or semiconductor system (or apparatus or device) or a propagation medium. The computer-readable medium may include a computer-readable non-transitory storage medium such as a semiconductor or solid state memory, magnetic tape, a removable computer diskette, a random access memory (RAM) , a read-only memory (ROM) , a magnetic disk and an optical disk, and the like. The computer-readable non-transitory storage medium can include all types of computer readable medium, including magnetic storage medium, optical storage medium, flash medium and solid state storage medium.

While aspects of the present disclosure have been described in conjunction with the specific embodiments thereof that are proposed as examples, alternatives, modifications, and variations to the examples may be made. Accordingly, embodiments as set forth herein are intended to be illustrative and not limiting. There are changes that may be made without departing from the scope of the claims set forth below.

Claims

A spatial relation switch method when the spatial relation configuration is associated with (QCLed with) a DL RS, comprising:

RRC configures the spatial relation list and measurement objects;

The UE measures and report the L1-RSRP based on the configured measurement objects;

The UE receives a configuration for target spatial relation switching based on the reported L1-RSRP;

The UE parses the spatial relation configuration;

The UE performs fine time tracking on the target RS of the configured spatial relation; and

The UE performs the spatial relation.
A spatial relation switch method when the spatial relation configuration is associated with (QCLed with) a DL RS, comprising:

RRC configures the spatial relation list and measurement objects;

The UE measures and report the L1-RSRP based on the configured measurement objects;

The UE receives a configuration for target spatial relation switching but not measured;

The UE parses the spatial relation configuration;

The UE measures the L1-RSRP for the configured RS;

The UE performs fine time tracking on the target RS of the configured spatial relation; and

The UE performs the spatial relation.
The method of claim 2, wherein the network may not configure the measurement objects and the UE may not measure and report the L1-RSRP based on the configured measurement objects.
The method of claim 2, wherein UE shall be allowed to transmit signals with previous spatial domain transmission filter when UE execute the L1-RSRP measurement to train the downlink spatial domain filter before transmitting the uplink signals.
A spatial relation switch method when the spatial relation configuration is associated with (QCLed with) a UL RS, comprising:

RRC configures the spatial relation list;

The UE receives a configuration for target spatial relation switching;

The UE parses the spatial relation configuration; and

The UE performs the spatial relation based on the transmission of configured UL RS index.
The method of claim 5, wherein the MAC based active spatial relation switch shall be defined when active spatial relation switches for PUCCH.
The method of claim 5, wherein PUSCH spatial relation activation shall only follow the related PUCCH or SRS spatial relation switch procedure.
The method of claim 5, wherein the aperiodic SRS should always associate with a known spatial relation.