CN111480302A

CN111480302A - User equipment and wireless communication method thereof

Info

Publication number: CN111480302A
Application number: CN201880081141.7A
Authority: CN
Inventors: 林晖闵; 唐海
Original assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Current assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Priority date: 2018-02-02
Filing date: 2018-02-02
Publication date: 2020-07-31
Anticipated expiration: 2038-02-02
Also published as: CN111480302B; CN116436504A; WO2019148455A1

Abstract

A user equipment and a wireless communication method thereof are provided. The user equipment includes a memory and a processor coupled to the memory. The processor is configured to perform group communication to at least one second user equipment through the sidelink interface, and to periodically perform beam scanning of at least one Tracking Reference Signal (TRS) towards the at least one second user equipment in different spatial directions in a burst set of TRSs.

Description

User equipment and wireless communication method thereof

Background of the disclosure

1. Field of the disclosure

The present disclosure relates to the field of communication systems, and more particularly, to a user equipment and a wireless communication method thereof.

2. Description of the related Art

Combining this with the trend of employing more antenna elements in user equipment, such as mobile phones and wireless devices in vehicles, recent designs of 5G-NRs for downlink (D L) and uplink (U L) operation incorporate massive MIMO technology to achieve "pencil-like" beam transmission by employing a large number of antenna elements at the Base Station (BS), thereby improving signal coverage and increasing data throughput.

For NR sidelink technology via PC5 interface for direct user equipment to user equipment (UE-to-UE) discovery and communication without BS routing, it is expected that MIMO and/or beamforming-like operation may also be supported to enhance system operation and support more advanced use cases however, in current long term evolution (L TE) sidelink technology for device to device (D2D) communication and vehicle to vehicle (V2V), vehicle to pedestrian (V2P) and vehicle to infrastructure/network (V2I/N) communications, beamforming and beamforming-like operation are not supported.

Disclosure of Invention

An object of the present disclosure is to provide a User Equipment (UE) and a wireless communication method thereof, which are capable of performing a beamforming operation and setting transmission-related parameters for sidelink communication in a group environment.

In a first aspect of the disclosure, a user equipment for wireless communication includes a memory and a processor coupled to the memory. The processor is configured to perform group communication to the at least one second user equipment over the sidelink interface, and to periodically perform beam scanning of the at least one Tracking Reference Signal (TRS) towards the at least one second user equipment in different spatial directions in a burst set (burst set) of the at least one TRS.

According to an embodiment in combination with the first aspect of the disclosure, the processor is further configured to receive reporting information from the at least one second user equipment, the reporting information comprising at least one of information relating to the selected optimal beam scanning direction and information relating to a setting of a transmission parameter.

According to an embodiment in combination with the first aspect of the disclosure, the processor is configured to periodically perform beam scanning of the at least one TRS towards the at least one second user equipment in different spatial directions in a burst set of the at least one TRS according to at least one of a travelling speed of the user equipment and a frequency interval (tone spacing) of a transmission carrier.

According to an embodiment in combination with the first aspect of the disclosure, the burst set of at least one TRS includes at least one of a full beam sweep mode and a compressed (dense) beam sweep mode.

According to an embodiment in combination with the first aspect of the disclosure, the burst set of at least one TRS is in a full beam scanning mode, each beam scanning direction is applied for an entire transmission of a Transmission Time Interval (TTI), and a duration of the burst set of at least one TRS is a number of beam scanning directions multiplied by a length of the TTI.

According to an embodiment incorporating the first aspect of the present disclosure, the TTI for each beam scanning direction includes a Guard Period (GP)/Automatic Gain Control (AGC) region, a physical side link control channel (PSCCH), a training RS, and a physical side link shared channel (PSCCH).

According to an embodiment in combination with the first aspect of the present disclosure, the PSCCH carries at least a part of a source identification of the user equipment, a beam index number for the at least one TRS, a resource allocation and size of the at least one TRS within a TTI, a power offset of a beam transmission of the at least one TRS, an absolute power of a beam transmission of the at least one TRS, and a resource allocation of the PSCCH within the TTI.

According to an embodiment in combination with the first aspect of the disclosure, the source identification is a Media Access Control (MAC) layer address.

According to an embodiment in combination with the first aspect of the present disclosure, the power offset indicates a difference between Min { P _ powerclass, P _ cmax } and the actual TRS transmit power, where P _ powerclass is a power class level of the user equipment for the communication band, and P _ cmax is a maximum output power configured for the serving cell when in network coverage or a maximum output power preconfigured when out of network coverage.

According to an embodiment incorporating the first aspect of the present disclosure, a zero power offset implies the maximum power level allowed by the network for TRS transmissions.

According to an embodiment in combination with the first aspect of the disclosure, the maximum power level is configured to be used during an initial group communication over the sidelink interface or in a queuing operation of the user equipment to the at least one second user equipment.

According to an embodiment incorporating the first aspect of the present disclosure, a non-zero power offset implies a power lower than the maximum power level.

According to an embodiment incorporating the first aspect of the present disclosure, a burst set of at least one TRS in a compressed beam scanning mode is applied for the entire transmission of a TTI and includes a Guard Period (GP)/Automatic Gain Control (AGC) region, a PSCCH carrying Sidelink Control Information (SCI) for scheduling the at least one TRS, and a TRS beam scanning region.

According to an embodiment in combination with the first aspect of the disclosure, the SCI includes at least a part of a source identification of the user equipment, a number of at least one TRS within a burst set of the at least one TRS in a compressed beam scanning mode, a power offset of a beam transmission of the at least one TRS, an absolute power of a beam transmission of the at least one TRS, a processing gap (gap) length, and a beam feedback.

According to an embodiment in combination with the first aspect of the disclosure, the number of at least one TRS within the burst set of at least one TRS in a compressed beam scanning mode corresponds to the number of beam scanning directions.

According to an embodiment in combination with the first aspect of the disclosure, the SCI further indicates at least one of a gap region and a feedback region.

In a second aspect of the disclosure, a user equipment for wireless communication includes a memory and a processor coupled to the memory. The processor is configured to perform group communication to at least one second user equipment through a sidelink interface, receive at least one Tracking Reference Signal (TRS) from the at least one second user equipment in different spatial directions in a burst set of TRSs, calculate at least one of a Reference Signal Received Power (RSRP) and a Received Signal Strength Indication (RSSI) for at least one TRS in the burst set of TRSs, and select an optimal beam scanning direction based on at least one of an optimal RSRP result and an optimal RSSI result.

According to another embodiment in combination with the second aspect of the disclosure, the processor is further configured to determine the optimal beam scanning direction for the transmission towards the at least one second user equipment based on at least one of an estimated time of arrival (ToA), angle of arrival (AoA) and direction of arrival (DoA) of the optimal beam scanning direction from the at least one second user equipment.

According to another embodiment in combination with the second aspect of the disclosure, the number of the at least one second user equipment is at least two, the optimal beam scanning direction towards one second user equipment is also the optimal beam scanning direction for another second user equipment.

According to another embodiment in combination with the second aspect of the disclosure, the processor is further configured to transmit report information to the at least one second user equipment, the report information comprising at least one of information relating to the optimal beam scanning direction and information relating to a setting of a transmission parameter.

According to another embodiment in combination with the second aspect of the disclosure, the burst set of at least one TRS includes at least one of a full beam scanning mode and a compressed beam scanning mode.

According to another embodiment incorporating the second aspect of the present disclosure, the burst set of at least one TRS is in a full beam scanning mode, each beam scanning direction is applied to an entire transmission of a Transmission Time Interval (TTI), and a duration of the burst set of at least one TRS is a number of beam scanning directions multiplied by a length of the TTI.

According to another embodiment incorporating the second aspect of the present disclosure, the TTI for each beam scanning direction includes a Guard Period (GP)/Automatic Gain Control (AGC) region, a physical side link control channel (PSCCH), a training RS, and a physical side link shared channel (PSCCH).

According to another embodiment in combination with the second aspect of the present disclosure, the PSCCH carries at least a part of a source identification of the at least one second user equipment, a beam index number for the at least one TRS, a resource allocation and size of the at least one TRS within a TTI, a power offset of a beam transmission of the at least one TRS, an absolute power of a beam transmission of the at least one TRS, and a resource allocation of the PSCCH within the TTI.

According to another embodiment in combination with the second aspect of the disclosure, the source identification is a Media Access Control (MAC) layer address.

According to another embodiment in combination with the second aspect of the disclosure, the power offset indicates a difference between Min { P _ powerclass, P _ cmax } and the actual TRS transmit power, wherein P _ powerclass is a power class level for the at least one second user equipment of the communication band and P _ cmax is a maximum output power configured for the serving cell when in network coverage or a maximum output power preconfigured when out of network coverage.

According to another embodiment incorporating the second aspect of the present disclosure, a zero power offset implies the maximum power level allowed by the network for TRS transmissions.

According to a further embodiment in combination with the second aspect of the disclosure, the maximum power level is configured to be used during an initial group communication over the sidelink interface or in a queuing operation of the user equipment to the at least one second user equipment.

According to another embodiment incorporating the second aspect of the disclosure, the non-zero power offset implies a power lower than the maximum power level.

According to another embodiment incorporating the second aspect of the present disclosure, the burst set of at least one TRS in a compressed beam scanning mode is applied for the entire transmission of a TTI and includes a Guard Period (GP)/Automatic Gain Control (AGC) region, a PSCCH carrying Sidelink Control Information (SCI) for scheduling the at least one TRS, and a TRS beam scanning region.

According to another embodiment in combination with the second aspect of the disclosure, the SCI includes at least a portion of a source identification, a number of at least one TRS within a burst set of the at least one TRS in a compressed beam scanning mode, a power offset of a beam transmission of the at least one TRS, an absolute power of a beam transmission of the at least one TRS, a processing gap length, and beam feedback.

According to another embodiment in combination with the second aspect of the disclosure, the power offset indicates a difference between Min { P _ powerclass, P _ cmax } and the actual TRS transmit power, wherein P _ powerclass is a power class level for the at least one second user equipment of the communication band and P _ cmax is a maximum output power configured for the serving cell when in network coverage or a maximum output power preconfigured when outside network coverage.

According to another embodiment in combination with the second aspect of the disclosure, the number of at least one TRS within the burst set of at least one TRS in the compressed beam scanning mode corresponds to the number of beam scanning directions.

According to another embodiment in combination with the second aspect of the disclosure, the SCI further indicates at least one of a gap region and a feedback region.

According to another embodiment in combination with the second aspect of the disclosure, the processor is further configured to derive a path loss measurement for an optimal beam scanning direction from the at least one second user equipment.

According to another embodiment in combination with the second aspect of the disclosure, the processor is further configured to derive the path loss measurement according to at least one of the following equations:

path L oss (P L) ═ Min { P _ powerclass, P _ cmax } -power _ offset-RSRP, or

PathLoss(PL)＝Min{P_powerclass,P_cmax}–power_offset–RSSI，

Wherein power _ offset indicates a difference between Min { P _ powerclass, P _ cmax } and an actual TRS transmit power, P _ powerclass being a power class level for at least one second user equipment of the communication band, P _ cmax being a maximum output power configured for the serving cell when in network coverage or a maximum output power preconfigured when outside of network coverage.

According to another embodiment in combination with the second aspect of the disclosure, the processor is further configured to determine a Modulation and Coding Scheme (MCS) level for a next transmission from the at least one second user equipment based on the path loss measurement.

According to another embodiment in combination with the second aspect of the disclosure, the processor is further configured to determine the MCS level for the next transmission from the at least one second user equipment based on the highest path loss measurement.

According to another embodiment in combination with the second aspect of the disclosure, the processor is further configured to maintain a data buffer of the user equipment at a minimum level and to determine the highest MCS based on a respective power of at least the second user equipment such that MCS < ═ Min { P _ powerclass, P _ cmax }.

According to another embodiment in combination with the second aspect of the disclosure, the processor is further configured to set an output power level for the at least one second user equipment for a next transmission based on the MCS level and the path loss measurement.

In a third aspect of the disclosure, a method of wireless communication of a user equipment includes performing group communication to at least one second user equipment over a sidelink interface, and periodically performing beam scanning of the at least one Tracking Reference Signal (TRS) towards the at least one second user equipment in different spatial directions in a burst set of TRSs.

According to another embodiment in combination with the third aspect of the present disclosure, the method further comprises receiving reporting information from the at least one second user equipment, the reporting information comprising at least one of information related to the selected optimal beam scanning direction and information related to the setting of the transmission parameters.

According to another embodiment in combination with the third aspect of the present disclosure, the method further comprises periodically performing beam scanning of the at least one TRS towards the at least one second user equipment in different spatial directions in the burst set of the at least one TRS according to at least one of a traveling speed of the user equipment and a frequency interval of the transmission carrier.

According to another embodiment in combination with the third aspect of the present disclosure, the burst set of at least one TRS includes at least one of a full beam scanning mode and a compressed beam scanning mode.

According to another embodiment in combination with the third aspect of the disclosure, the burst set of at least one TRS is in a full beam scanning mode, each beam scanning direction is applied to an entire transmission of a Transmission Time Interval (TTI), and a duration of the burst set of at least one TRS is a number of beam scanning directions multiplied by a length of the TTI.

According to another embodiment incorporating the third aspect of the present disclosure, the TTI for each beam scanning direction includes a Guard Period (GP)/Automatic Gain Control (AGC) region, a physical side link control channel (PSCCH), a training RS, and a physical side link shared channel (PSCCH).

According to another embodiment in combination with the third aspect of the present disclosure, the PSCCH carries at least a part of a source identification of the user equipment, a beam index number for the at least one TRS, a resource allocation and size of the at least one TRS within a TTI, a power offset of a beam transmission of the at least one TRS, an absolute power of a beam transmission of the at least one TRS, and a resource allocation of the PSCCH within the TTI.

According to another embodiment in combination with the third aspect of the disclosure, the source identification is a Media Access Control (MAC) layer address.

According to another embodiment in combination with the third aspect of the present disclosure, the power offset indicates a difference between Min { P _ powerclass, P _ cmax } and the actual TRS transmit power, where P _ powerclass is a power class level of the user equipment for the communication band, and P _ cmax is a maximum output power configured for the serving cell when in network coverage or a maximum output power preconfigured when out of network coverage.

According to another embodiment incorporating the third aspect of the present disclosure, zero power offset implies the maximum power level allowed by the network for TRS transmissions.

According to another embodiment in combination with the third aspect of the disclosure, the maximum power level is configured to be used during an initial group communication over the sidelink interface or in a queuing operation of the user equipment to the at least one second user equipment.

According to another embodiment in combination with the third aspect of the disclosure, the non-zero power offset implies a power lower than the maximum power level.

According to another embodiment in combination with the third aspect of the present disclosure, the method further comprises that a burst set of at least one TRS in a compressed beam scanning mode is applied for the entire transmission of a TTI and comprises a Guard Period (GP)/Automatic Gain Control (AGC) region, a PSCCH carrying Sidelink Control Information (SCI) for scheduling the at least one TRS, and a TRS beam scanning region.

According to another embodiment in combination with the third aspect of the present disclosure, the SCI includes at least a portion of a source identification of the user equipment, a number of at least one TRS within a burst set of the at least one TRS in a compressed beam scanning mode, a power offset of a beam transmission of the at least one TRS, an absolute power of a beam transmission of the at least one TRS, a processing gap length, and beam feedback.

According to another embodiment in combination with the third aspect of the disclosure, the power offset indicates a difference between Min { P _ powerclass, P _ cmax } and the actual TRS transmit power, where P _ powerclass is a power class level of the user equipment for the communication band and P _ cmax is a maximum output power configured for the serving cell when in network coverage or a preconfigured maximum output power when out of network coverage.

According to another embodiment in combination with the third aspect of the present disclosure, the number of at least one TRS within the burst set of at least one TRS in a compressed beam scanning mode corresponds to the number of beam scanning directions.

According to another embodiment in combination with the third aspect of the disclosure, the SCI further indicates at least one of a gap region and a feedback region.

In a fourth aspect of the present disclosure, a method of wireless communication of a user equipment includes: performing group communication to at least one second user equipment over a sidelink interface, receiving at least one Tracking Reference Signal (TRS) from the at least one second user equipment in different spatial directions in a burst set of TRSs, calculating at least one of a Reference Signal Received Power (RSRP) and a Received Signal Strength Indication (RSSI) for the at least one TRS in the burst set of TRSs, and selecting an optimal beam scanning direction based on at least one of the optimal RSRP result and the optimal RSSI result.

According to another embodiment in combination with the fourth aspect of the disclosure, the method further comprises determining the optimal beam scanning direction for the transmission towards the at least one second user equipment based on at least one of an estimated time of arrival (ToA), angle of arrival (AoA) and direction of arrival (DoA) of the optimal beam scanning direction from the at least one second user equipment.

According to another embodiment in combination with the fourth aspect of the disclosure, the number of the at least one second user equipment is at least two, the optimal beam scanning direction towards one second user equipment is also the optimal beam scanning direction for another second user equipment.

According to another embodiment in combination with the fourth aspect of the disclosure, the method further comprises transmitting report information to the at least one second user equipment, the report information comprising at least one of information relating to the optimal beam scanning direction and information relating to a setting of a transmission parameter.

According to another embodiment in combination with the fourth aspect of the disclosure, the burst set of at least one TRS includes at least one of a full beam scanning mode and a compressed beam scanning mode.

According to another embodiment incorporating the fourth aspect of the present disclosure, the burst set of at least one TRS is in a full beam scanning mode, each beam scanning direction is applied to an entire transmission of a Transmission Time Interval (TTI), and a duration of the burst set of at least one TRS is a number of beam scanning directions multiplied by a length of the TTI.

According to another embodiment incorporating the fourth aspect of the present disclosure, the TTI for each beam scanning direction includes a Guard Period (GP)/Automatic Gain Control (AGC) region, a physical side link control channel (PSCCH), a training RS, and a physical side link shared channel (PSCCH).

According to another embodiment in combination with the fourth aspect of the present disclosure, the PSCCH carries at least a part of a source identification of the at least one second user equipment, a beam index number for the at least one TRS, a resource allocation and size of the at least one TRS within a TTI, a power offset of a beam transmission of the at least one TRS, an absolute power of a beam transmission of the at least one TRS, and a resource allocation of the PSCCH within the TTI.

According to another embodiment in combination with the fourth aspect of the disclosure, the source identification is a Media Access Control (MAC) layer address.

According to another embodiment in combination with the fourth aspect of the disclosure, the power offset indicates a difference between Min { P _ powerclass, P _ cmax } and the actual TRS transmit power, wherein P _ powerclass is a power class level for the at least one second user equipment of the communication band and P _ cmax is a maximum output power configured for the serving cell when in network coverage or a maximum output power preconfigured when outside network coverage.

According to another embodiment incorporating the fourth aspect of the present disclosure, a zero power offset implies the maximum power level allowed by the network for TRS transmissions.

According to a further embodiment in combination with the fourth aspect of the disclosure, the maximum power level is configured to be used during an initial group communication over the sidelink interface or in a queuing operation of the user equipment to the at least one second user equipment.

According to another embodiment incorporating the fourth aspect of the disclosure, the non-zero power offset implies a power lower than the maximum power level.

According to another embodiment incorporating the fourth aspect of the present disclosure, the burst set of at least one TRS in a compressed beam scanning mode is applied for the entire transmission of a TTI and includes a Guard Period (GP)/Automatic Gain Control (AGC) region, a PSCCH carrying Sidelink Control Information (SCI) for scheduling the at least one TRS, and a TRS beam scanning region.

According to another embodiment in combination with the fourth aspect of the disclosure, the SCI includes at least a portion of a source identification, a number of at least one TRS within a burst set of the at least one TRS in a compressed beam scanning mode, a power offset of a beam transmission of the at least one TRS, an absolute power of a beam transmission of the at least one TRS, a processing gap length, and beam feedback.

According to another embodiment in combination with the fourth aspect of the disclosure, the number of at least one TRS within the burst set of at least one TRS in the compressed beam scanning mode corresponds to the number of beam scanning directions.

According to another embodiment in combination with the fourth aspect of the disclosure, the SCI further indicates at least one of a gap region and a feedback region.

According to a further embodiment in combination with the fourth aspect of the disclosure, the method further comprises deriving a path loss measurement for an optimal beam scanning direction from the at least one second user equipment.

According to another embodiment in combination with the fourth aspect of the disclosure, the method further comprises deriving the path loss measurement according to at least one of the following equations:

path L oss (P L) ═ Min { P _ powerclass, P _ cmax } -power _ offset-RSRP, or

PathLoss(PL)＝Min{P_powerclass,P_cmax}–power_offset–RSSI，

According to another embodiment in combination with the fourth aspect of the disclosure, the method further comprises determining a Modulation and Coding Scheme (MCS) level for a next transmission from the at least one second user equipment based on the path loss measurement.

According to another embodiment in combination with the fourth aspect of the disclosure, the method further comprises determining the MCS level for the next transmission from the at least one second user equipment based on the highest path loss measurement.

According to a further embodiment in combination with the fourth aspect of the disclosure, the method further comprises maintaining a data buffer of the user equipment at a minimum level and determining the highest MCS based on the respective power of at least the second user equipment such that MCS < ═ Min { P _ power class, P _ cmax }.

According to another embodiment in combination with the fourth aspect of the disclosure, the method further comprises setting an output power level for the at least one second user equipment for a next transmission based on the MCS level and the path loss measurement.

In a fifth aspect of the disclosure, a user equipment for wireless communication includes a memory and a processor coupled to the memory. The processor is configured to perform group communications to at least one second user equipment over a sidelink interface, receive at least one Tracking Reference Signal (TRS) from the at least one second user equipment in different spatial directions in a burst set of TRSs, wherein the burst set of TRSs is in a full beam sweep mode, each beam sweep direction is applied for an entire transmission of a Transmission Time Interval (TTI), and a duration of the burst set of TRSs is a number of beam sweep directions multiplied by a length of the TTI.

According to another embodiment incorporating the fifth aspect of the present disclosure, the TTI for each beam scanning direction includes a Guard Period (GP)/Automatic Gain Control (AGC) region, a physical side link control channel (PSCCH), a training RS, and a physical side link shared channel (PSCCH).

According to another embodiment in combination with the fifth aspect of the disclosure, the PSCCH carries at least a part of a source identification of the at least one second user equipment, a beam index number for the at least one TRS, a resource allocation and size of the at least one TRS within a TTI, a power offset of a beam transmission of the at least one TRS, an absolute power of a beam transmission of the at least one TRS, and a resource allocation of the PSCCH within the TTI.

According to another embodiment in combination with the fifth aspect of the disclosure, the source identification is a Media Access Control (MAC) layer address.

According to another embodiment in combination with the fifth aspect of the disclosure, the power offset indicates a difference between Min { P _ powerclass, P _ cmax } and the actual TRS transmit power, wherein P _ powerclass is a power class level for the at least one second user equipment of the communication band and P _ cmax is a maximum output power configured for the serving cell when in network coverage or a maximum output power preconfigured when outside network coverage.

According to another embodiment incorporating the fifth aspect of the present disclosure, zero power offset implies the maximum power level allowed by the network for TRS transmission.

According to a further embodiment in combination with the fifth aspect of the disclosure, the maximum power level is configured to be used during an initial group communication over the sidelink interface or in a queuing operation of the user equipment to the at least one second user equipment.

According to another embodiment incorporating the fifth aspect of the disclosure, the non-zero power offset implies a power lower than the maximum power level.

In a sixth aspect of the disclosure, a user equipment for wireless communication includes a memory and a processor coupled to the memory. The processor is configured to perform group communication to at least one second user equipment over a sidelink interface, receive at least one Tracking Reference Signal (TRS) in a different spatial direction in a burst set of TRSs from the at least one second user equipment, wherein the burst set of TRSs is in a compressed beam scanning mode and includes a Guard Period (GP)/Automatic Gain Control (AGC) region, a PSCCH carrying Sidelink Control Information (SCI) for scheduling the at least one TRS, and a TRS beam scanning region, and select an optimal beam scanning direction.

According to another embodiment in combination with the sixth aspect of the disclosure, the SCI includes at least a portion of a source identification, a number of at least one TRS within a burst set of the at least one TRS in a compressed beam scanning mode, a power offset of a beam transmission of the at least one TRS, an absolute power of a beam transmission of the at least one TRS, a processing gap length, and beam feedback.

According to another embodiment in combination with the sixth aspect of the disclosure, the source identification is a Media Access Control (MAC) layer address.

According to another embodiment in combination with the sixth aspect of the disclosure, the power offset indicates a difference between Min { P _ powerclass, P _ cmax } and the actual TRS transmit power, wherein P _ powerclass is a power class level for the at least one second user equipment of the communication band and P _ cmax is a maximum output power configured for the serving cell when in network coverage or a maximum output power preconfigured when outside network coverage.

According to another embodiment incorporating the sixth aspect of the present disclosure, zero power offset implies the maximum power level allowed by the network for TRS transmissions.

According to a further embodiment in combination with the sixth aspect of the disclosure, the maximum power level is configured to be used during an initial group communication over the sidelink interface or in a queuing operation of the user equipment to the at least one second user equipment.

According to another embodiment incorporating the sixth aspect of the disclosure, the non-zero power offset implies a power lower than the maximum power level.

According to another embodiment in combination with the sixth aspect of the disclosure, the number of at least one TRS within the burst set of at least one TRS in the compressed beam scanning mode corresponds to the number of beam scanning directions.

According to another embodiment in combination with the sixth aspect of the disclosure, the SCI further indicates at least one of a gap region and a feedback region.

In an embodiment of the present disclosure, a user equipment and a wireless communication method thereof are capable of performing beamforming operation and setting transmission-related parameters for sidelink communication in a group environment, so that the user equipment may save a battery, perform long-time operation, and/or have good operation performance due to less interference.

Drawings

In order to more clearly illustrate embodiments of the present disclosure or related art, the following drawings, which will be described in the embodiments, are briefly introduced. It is to be understood that the drawings are merely exemplary of the disclosure and that other drawings can be derived by one of ordinary skill in the art without undue effort.

Fig. 1 is a block diagram of a user equipment for wireless communication according to an embodiment of the present disclosure.

Fig. 2 is a flow chart illustrating a method of wireless communication in accordance with the present disclosure in terms of operation of a user equipment for transmitting signals.

Fig. 3 is a flow chart illustrating a method of wireless communication in accordance with the present disclosure, in terms of operation of a user equipment for receiving signals.

Fig. 4 is a beam scan pattern of at least one Tracking Reference Signal (TRS) according to an embodiment of the present disclosure.

Fig. 5 is a diagram of a burst set of at least one TRS in a full beam sweep mode according to an embodiment of the present disclosure.

Fig. 6 is a diagram of a burst set of at least one TRS in a compressed beam scanning mode according to an embodiment of the present disclosure.

Fig. 7 is a scenario in which multiple user devices are engaged in sidelink group communication, according to an embodiment of the present disclosure.

Detailed description of the embodiments

Embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings by technical subject matter, structural features, and objects and effects achieved. In particular, the terminology used in the embodiments of the present disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure.

Fig. 1 illustrates that in some embodiments, at least one User Equipment (UE)100 for wireless communication includes a memory 102 and a processor 104 coupled to the memory 102, the processor 104 is configured to perform group communication to the at least one user equipment 200 over a sidelink interface, such as a PC5 interface, and to periodically perform beam scanning of the at least one Tracking Reference Signal (TRS) towards the at least one user equipment 200 in different spatial directions in a burst set of the TRS, such that the at least one user equipment 100 may conserve battery, operate for a long time, and/or have good performance due to less interference.

Fig. 1 further illustrates that, in some embodiments, at least one user equipment 200 for wireless communication includes a memory 202 and a processor 204 coupled to the memory 202. The processor 204 is configured to perform group communication with at least one user equipment 100 over a sidelink interface, such as a PC5 interface, receive at least one Tracking Reference Signal (TRS) from the at least one user equipment 100 in different spatial directions in a burst set of the TRS, calculate at least one of a Reference Signal Received Power (RSRP) and a Received Signal Strength Indication (RSSI) for the at least one TRS in the burst set of the at least one TRS, and select an optimal beam scanning direction based on at least one of the optimal RSRP result and the optimal RSSI result, such that the at least one user equipment 100 may save battery, operate for a long time, and/or have good performance due to less interference.

In some embodiments, the processor 204 is further configured to determine an optimal beam scanning direction for transmissions towards the at least one user equipment 100 based on at least one of an estimated time of arrival (ToA), angle of arrival (AoA) and direction of arrival (DoA) of the optimal beam scanning direction from the at least one user equipment 100. The number of at least one user equipment 100 is at least two, and the optimal beam scanning direction towards one user equipment 100 is also the optimal beam scanning direction for another user equipment 100. The processor 204 is further configured to transmit reporting information to the at least one user equipment 100, the reporting information comprising at least one of information related to the optimal beam scanning direction and information related to the setting of the transmission parameters.

In some embodiments, the processor 204 is further configured to derive a path loss measurement for the best beam scan direction from the at least one user equipment 100. The processor 204 is further configured to derive a path loss measurement according to at least one of the following equations:

path L oss (P L) ═ Min { P _ powerclass, P _ cmax } -power _ offset-RSRP, or

PathLoss(PL)＝Min{P_powerclass,P_cmax}–power_offset–RSSI。

Wherein power _ offset indicates a difference between Min { P _ powerclass, P _ cmax } and an actual TRS transmission power, P _ powerclass being a power class level for at least one user equipment 100 of a communication band, and P _ cmax being a maximum output power configured for a serving cell when in network coverage or a maximum output power preconfigured when out of network coverage.

In some embodiments, the processor 204 is further configured to determine a Modulation and Coding Scheme (MCS) level for a next transmission from the at least one user equipment 100 based on the path loss measurement. The processor 204 is further configured to determine an MCS level for a next transmission from the at least one user equipment 100 based on the highest path loss measurement. The processor 204 is further configured to keep the data buffering of the user equipment 200 at a minimum level and to determine the highest MCS based on at least the respective power of the user equipment 100 such that MCS < <min { P _ powerclass, P _ cmax }. The processor 204 is further configured to set an output power level for the at least one user equipment 100 for the next transmission based on the MCS level and the path loss measurement.

In some embodiments,

memories

102 and 202 may each include Read Only Memory (ROM), Random Access Memory (RAM), flash memory, memory cards, storage media, and/or other storage devices.

Processors

104 and 204 may each comprise an Application Specific Integrated Circuit (ASIC), other chipset, logic circuit, and/or data processing device. Each of the

processors

104 and 204 may also 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. These modules can be stored in the

memories

102 and 202 and executed by the

processors

104 and 204. The

memories

102 and 202 can be implemented within the

processors

104 and 204 or external to the

processors

104 and 204, in which case they can be communicatively coupled to the

processors

104 and 204 via various means as is known in the art.

In some embodiments, the group communication between the at least one user equipment 100 and the at least one user equipment 200 involves vehicle-to-vehicle (V2X) communication according to L TE sidelink technology and/or 5G-NR radio access technology developed under 3GPP release 14, where V2X communication includes vehicle-to-vehicle (V2V), vehicle-to-pedestrian (V2P), and vehicle-to-infrastructure/network (V2I/N).

Fig. 2 illustrates a wireless communication method 300 in accordance with the present disclosure in terms of operation of the user equipment 100 for transmitting signals. The method 300 includes: group communication to the at least one user equipment 200 is performed over a sidelink interface, such as a PC5 interface, at block 302, and beam scanning of the at least one Tracking Reference Signal (TRS) is performed periodically towards the at least one user equipment 200 in different spatial directions in a burst set of TRS, at block 304, such that the at least one user equipment 100 may save battery, operate for a long time, and/or have good performance due to less interference.

Fig. 3 illustrates, in terms of operation of user equipment 200 for receiving signals, a method 400 of wireless communication in accordance with the present disclosure. The method 400 includes: at block 402, performing group communication to at least one user equipment 100 over a sidelink interface, such as a PC5 interface, at block 404, receiving at least one Tracking Reference Signal (TRS) in different spatial directions in a burst set of TRSs from the at least one user equipment 100, at block 406, calculating at least one of a Reference Signal Received Power (RSRP) and a Received Signal Strength Indication (RSSI) for the at least one TRS in the burst set of TRSs, and at block 408, selecting an optimal beam scanning direction based on at least one of the optimal RSRP result and the optimal RSSI result, such that the at least one user equipment 100 may save battery, operate for a long time, and/or have good performance due to less interference.

Fig. 1 and 4 to 6 show that, in some embodiments, the processor 104 is further configured to receive reporting information from the at least one user equipment 200, the reporting information comprising at least one of information relating to the selected optimal beam scanning direction and information relating to the setting of the transmission parameters. The processor 104 is configured to periodically perform beam scanning of the at least one TRS to the at least one user equipment 200 in different spatial directions in a burst set of the at least one TRS according to at least one of a travel speed of the at least one user equipment 100 and a frequency interval of a transmission carrier. For example, the processor 104 is configured to perform beam scanning of at least one TRS at each periodic interval, e.g., 5ms, 10ms, 20ms, 50ms, and 100 ms. The different spatial directions may be, for example, 4, 8, 16, 32 and 64 directions. The burst set of at least one TRS includes at least one of a full beam scan pattern as shown in fig. 5 and a compressed beam scan pattern as shown in fig. 6.

Fig. 1 and 5 show that in some embodiments, a burst set of at least one TRS is in a full beam scan mode. Each beam scanning direction is applied to the entire transmission of a Transmission Time Interval (TTI). The duration of the burst set of at least one TRS is the number of beam scanning directions multiplied by the length of the TTI. The TTI for each beam scanning direction includes a Guard Period (GP)/Automatic Gain Control (AGC) region, a physical side link control channel (PSCCH), a training RS, and a physical side link shared channel (PSCCH). The PSCCH carries at least a portion of a source identification of the user equipment 100, a beam index number for the at least one TRS, a resource allocation and size of the at least one TRS within a TTI, a power offset of a beam transmission of the at least one TRS, an absolute power of a beam transmission of the at least one TRS, and a resource allocation of the PSCCH within the TTI. The training RS may occupy one or more Orthogonal Frequency Division Multiplexing (OFDM) symbols. The psch may carry information data Transport Blocks (TBs). The source identification is a Media Access Control (MAC) layer address or a member number within a sidelink communication group that uniquely identifies the user equipment 100.

Fig. 1 and 5 further illustrate that, in some embodiments, the power offset indicates a difference between Min { P _ powerclass, P _ cmax } and the actual TRS transmit power, where P _ powerclass is a power class level of the user equipment for the communication band and P _ cmax is a maximum output power configured for the serving cell when in network coverage or a maximum output power preconfigured when out of network coverage. A zero power offset means the maximum power level allowed by the network for TRS transmissions. The maximum power level is configured to be used during initial group communication over the sidelink interface or in a queuing operation of the user equipment 100 to the at least one user equipment 200 to reach as many devices as possible to notify and invite new group members to join at any time. A non-zero power offset means a power lower than the maximum power level. The lower power level may be set based on the past history/detection of TRSs of other group members to limit transmission range and thereby generate less interference and achieve power savings.

Fig. 1 and 6 show that in some embodiments, a burst set of at least one TRS is in a compressed beam scanning mode. The burst set of at least one TRS in a compressed beam scanning mode is applied for the entire transmission of a TTI and includes a Guard Period (GP)/Automatic Gain Control (AGC) region, a PSCCH carrying Sidelink Control Information (SCI) for scheduling the at least one TRS, and a TRS beam scanning region. The SCI includes at least a portion of a source identification of the user equipment 100, a number of at least one TRS within a burst set of at least one TRS in a compressed beam scanning mode, a power offset of a beam transmission of the at least one TRS, an absolute power of a beam transmission of the at least one TRS, a processing gap length, and beam feedback.

In some embodiments, the source identification is a Media Access Control (MAC) layer address or a member number within a sidelink communication group that uniquely identifies the user equipment 100. The processing gap length may be a fixed length based on the number of OFDM symbols. The user equipment 200 uses the gap period for RSRP/RSSI measurement and selection of the best beam. The size of the beam feedback reporting region, and resources may be allocated to the group members for multiplexing beam reporting. At least one TRS is repeated and transmitted in all supported spatial directions. The length of the TRS transmission can be as short as one OFDM symbol. If the gap region is indicated in the SCI, the user equipment 200 can calculate RSRP/RSSI measurements for TRSs for each transmission in the gap region with the gap duration and select the best beam in the burst set. Based on the number of TRSs and the length of each TRS transmission, the user equipment 200 can determine the starting position of the gap region. If the feedback region is indicated in the SCI, the feedback region is used for beam reporting by the user equipment 200.

Fig. 1 and 6 further illustrate that, in some embodiments, the power offset indicates a difference between Min { P _ powerclass, P _ cmax } and the actual TRS transmit power, where P _ powerclass is a power class level of the user equipment for the communication band and P _ cmax is a maximum output power configured for the serving cell when in network coverage or a maximum output power preconfigured when out of network coverage. A zero power offset means the maximum power level allowed by the network for TRS transmissions. The maximum power level is configured to be used during initial group communication over the sidelink interface or in a queuing operation of the user equipment 100 to the at least one user equipment 200 to reach as many user equipments as possible, thereby notifying and inviting new group members to join at any time. A non-zero power offset means a power lower than the maximum power level. The lower power level may be set based on the past history/detection of TRSs of other group members to limit transmission range and thereby generate less interference and achieve power savings. The number of at least one TRS within the burst set of at least one TRS in the compressed beam scanning mode corresponds to the number of beam scanning directions. The SCI further indicates at least one of a gap region and a feedback region.

Fig. 7 illustrates that in some embodiments, in each beam scanning period of each transmitting user equipment, the receiving user equipment calculates RSRP or RSSI for each transmitted TRS within the burst set and selects the best beam based on the best RSRP/RSSI result, e.g., the highest RSRP/RSSI result. As an example in fig. 7, where there are six User Equipments (UEs) engaged in the sidelink group communication, and UE3 measures RSRP/RSSI of all received TRSs from all UEs and selects beam 3 as the best beam from UE1, beam 4 as the best beam from UE2, beam 1 as the best beam from UE4, beam 2 as the best beam from UE5, and beam 3 as the best beam from UE 6.

In some embodiments, the receiving UE determines the appropriate beam direction for the transmission towards each transmitting UE based on the estimated ToA, AoA and/or DoA of the selected best beam from each transmitting UE. Sometimes, the suitable beam direction towards one UE may also be the best suitable beam direction for another UE. As an example in fig. 7, the UE3 determines beam 1 as the best suitable direction for transmissions towards the UE4 and the UE6, beam 2 as the best suitable direction for transmissions towards the UE1 and the UE5, and beam 3 as the best suitable direction for transmissions towards the UE 2.

In some embodiments, the receiving UE derives Path loss measurements from the RSRP/RSSI result for each selected best beam and the corresponding power _ offset indicated in the SCI according to Path L oss (P L) ═ Min { P _ powerclass, P _ cmax } -power _ offset-RSRP/RSSI as in the example in fig. 7, UE3 derives the Path loss for the selected best beam from each UE the Path loss assumptions are that P L for beam 3 from UE1 is 6dB, P L for beam 4 from UE2 is 3dB, P L for beam 1 from UE4 is 3dB, P L for beam 2 from UE5 is 4dB, and P L for beam 3 from UE6 is 8 dB.

In some embodiments, in P L for the calculation of the best beam selected for each sending UE (tx UE), the receiving UE (Rx UE) determines the appropriate MCS level for the next transmission to the group-that is, the Rx UE selects the MCS level corresponding to the highest P L link so that the common MCS is used for the next multicast transmission and can decode all members of the group-at the same time, the Rx UE can also consider its own data buffer status in order to keep data buffering at a minimum level.

In some embodiments, based on the selected MCS level and the corresponding required Rx _ power, the UE determines the transmit power for each selected best beam direction from P _ Tx (beam x) ═ required Tx _ power (MCS) + P L (the selected best beam.) as an example in fig. 7, assuming an Rx power level of 10dBm would be required for the highest MCS level of the 8dB P L link from UE6, then UE3 would set its output power level for each transmit beam to:

p _ Tx (beam 1 towards UE4 and UE 6) 10dBm +8dB 18dBm,

p _ Tx (beam 2 towards UE1 and UE 5) ═ 10dBm +6dB ═ 16dBm, and

p _ Tx (beam 3 toward UE 2) ═ 10dBm +3dB ═ 13 dBm.

In an embodiment of the present disclosure, a user equipment and a wireless communication method thereof can perform a beamforming operation and set transmission-related parameters for sidelink communication in a group environment, so that the user equipment can save a battery, operate for a long time, and/or have good operation performance due to less interference.

One of ordinary skill in the art understands that each unit, algorithm, and step described and disclosed in the embodiments of the present disclosure is implemented using electronic hardware or a combination of software and electronic hardware for a computer. Whether these functions are run in hardware or software depends on the conditions and design requirements of the application of the solution. Those of ordinary skill in the art may implement the functionality for each particular application in a variety of ways, and such implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure.

A person skilled in the art understands that he/she can refer to the working processes of the systems, devices and units in the above embodiments, since the working processes of the systems, devices and units are substantially the same. For ease of description and simplicity, these operations will not be described in detail.

It should be understood that the systems, devices, and methods disclosed in the embodiments of the present disclosure can be implemented in other ways. The above embodiments are merely exemplary. The division of cells is based solely on logic functions, while other divisions exist in implementations. Multiple units or components may be combined or integrated in another system. It is also possible to omit or skip some features. On the other hand, the mutual coupling, direct coupling or communicative coupling shown or discussed, whether indirectly or communicatively coupled through electrical, mechanical or other types of means, can be achieved through a number of ports, devices or units.

The elements that are separate components for explanation may or may not be physically separate. The unit for displaying may or may not be a physical unit, i.e. located in one place or distributed over a plurality of network elements. Some or all of the units are used according to the purpose of the embodiment.

Furthermore, each functional unit in each embodiment can be integrated in one processing unit, may be physically separate, or integrated in one processing unit having two or more units.

If the software functional unit is implemented, used and sold as a product, it can be stored in a readable storage medium in a computer. Based on this understanding, the technical solutions proposed by the present disclosure can be implemented basically or partially in the form of software products. Alternatively, a portion of the technical solutions that are advantageous for the conventional art can be implemented in the form of a software product. The software product in a computer is stored in a storage medium that includes a plurality of commands for a computing device (e.g., a personal computer, server, or network device) to execute all or some of the steps disclosed by embodiments of the present disclosure. The storage medium includes a USB disk, a removable hard disk, a Read Only Memory (ROM), a Random Access Memory (RAM), a floppy disk, or other type of medium capable of storing program code.

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

Claims

1. A user equipment for wireless communication, comprising:

a memory; and

a processor coupled to the memory and configured to:

performing a group communication to the at least one second user equipment through the sidelink interface; and

periodically performing beam scanning of the at least one tracking reference signal, TRS, in different spatial directions in a burst set of the at least one TRS towards the at least one second user equipment.

2. The user equipment of claim 1, wherein the processor is further configured to receive reporting information from the at least one second user equipment, the reporting information comprising at least one of information related to the selected optimal beam scanning direction and information related to a setting of a transmission parameter.

3. The user equipment of claim 1, wherein the processor is configured to periodically perform the beam scanning of the at least one TRS toward the at least one second user equipment in the different spatial directions in the set of bursts of the at least one TRS according to at least one of a traveling speed of the user equipment and a frequency interval of transmission carriers.

4. The user equipment of claim 1, wherein the set of bursts of the at least one TRS includes at least one of a full beam scan pattern and a compressed beam scan pattern.

5. The user equipment of claim 4, wherein the set of bursts of the at least one TRS are in the full beam scan mode, each beam scan direction is applied to an entire transmission of a Transmission Time Interval (TTI), and a duration of the set of bursts of the at least one TRS is a number of beam scan directions multiplied by a length of the TTI.

6. The user equipment of claim 5, wherein the TTI for each beam scanning direction comprises a guard period GP/Automatic Gain Control (AGC) region, a physical side link control channel (PSCCH), a training RS, and a physical side link shared channel (PSSCH).

7. The user equipment of claim 6, wherein the PSCCH carries at least a portion of a source identification of the user equipment, a beam index number for the at least one TRS, a resource allocation and size of the at least one TRS within the TTI, a power offset of a beam transmission of the at least one TRS, an absolute power of the beam transmission of the at least one TRS, and a resource allocation of the PSSCH within the TTI.

8. The user equipment of claim 7, wherein the source identification is a Media Access Control (MAC) layer address.

9. The user equipment of claim 7, wherein the power offset indicates a difference between Min { P _ powerclass, P _ cmax } and an actual TRS transmit power, where P _ powerclass is a power class level of the user equipment for a communication band and P _ cmax is a maximum output power configured for a serving cell when in network coverage or a maximum output power preconfigured when outside of the network coverage.

10. The user equipment of claim 9, wherein a zero power offset implies a maximum power level allowed by the network for TRS transmissions.

11. The user equipment of claim 10, wherein the maximum power level is configured for use during an initial group communication over the sidelink interface or in a queuing operation by the user equipment for the at least one second user equipment.

12. The user equipment of claim 9, wherein non-zero power offset means a power lower than the maximum power level.

13. The user equipment of claim 4, wherein the burst set of the at least one TRS in the compressed beam scanning mode is applied for an entire transmission of a Transmission Time Interval (TTI) and comprises a Guard Period (GP)/Automatic Gain Control (AGC) region, a PSCCH carrying Sidelink Control Information (SCI) for scheduling the at least one TRS, and a TRS beam scanning region.

14. The user equipment of claim 13, wherein the SCI comprises at least a portion of a source identification of the user equipment, a number of the at least one TRS within the burst set of the at least one TRS in the compressed beam scanning mode, a power offset of a beam transmission of the at least one TRS, an absolute power of the beam transmission of the at least one TRS, a processing gap length, and beam feedback.

15. The user equipment of claim 14, wherein the source identification is a Media Access Control (MAC) layer address.

16. The user equipment of claim 14, wherein the power offset indicates a difference between Min { P _ powerclass, P _ cmax } and an actual TRS transmit power, wherein P _ powerclass is a power class level of the user equipment for a communication band, and P _ cmax is a maximum output power configured for a serving cell when in network coverage or a maximum output power preconfigured when outside of the network coverage.

17. The user equipment of claim 16, wherein a zero power offset implies a maximum power level allowed by the network for TRS transmissions.

18. The user equipment of claim 17, wherein the maximum power level is configured for use during an initial group communication over the sidelink interface or in a queuing operation by the user equipment for the at least one second user equipment.

19. The user equipment of claim 16, wherein non-zero power offset means a power lower than the maximum power level.

20. The user equipment of claim 14, wherein the number of the at least one TRS within the set of bursts of the at least one TRS in the compressed beam scanning mode corresponds to a number of beam scanning directions.

21. The user equipment of claim 14, wherein the SCI further indicates at least one of a gap region and a feedback region.

22. A user equipment for wireless communication, comprising:

a memory; and

a processor coupled to the memory and configured to:

performing a group communication to the at least one second user equipment through the sidelink interface;

receiving, from the at least one second user equipment, at least one tracking reference signal, TRS, in different spatial directions in a burst set of TRSs;

calculating at least one of a reference signal received power, RSRP, and a received signal strength indication, RSSI, for the at least one TRS in the set of bursts for the at least one TRS; and

selecting an optimal beam scanning direction based on at least one of the optimal RSRP result and the optimal RSSI result.

23. The user equipment of claim 22, wherein the processor is further configured to determine the optimal beam scanning direction for transmissions towards the at least one second user equipment based on at least one of an estimated time of arrival (ToA), angle of arrival (AoA), and direction of arrival (DoA) of the optimal beam scanning direction from the at least one second user equipment.

24. The user equipment of claim 23, wherein the at least one second user equipment is at least two in number, the optimal beam scanning direction towards one second user equipment is also the optimal beam scanning direction for another second user equipment.

25. The user equipment of claim 22, wherein the processor is further configured to transmit reporting information to the at least one second user equipment, the reporting information comprising at least one of information related to the optimal beam scanning direction and information related to a setting of a transmission parameter.

26. The user equipment of claim 22, wherein the set of bursts of the at least one TRS includes at least one of a full beam scan pattern and a compressed beam scan pattern.

27. The user equipment of claim 26, wherein the set of bursts of the at least one TRS are in the full beam scanning mode, each beam scanning direction is applied to an entire transmission of a transmission time interval, TTI, and a duration of the set of bursts of the at least one TRS is a number of beam scanning directions multiplied by a length of the TTI.

28. The user equipment of claim 27, wherein the TTI for each beam scanning direction comprises a guard period GP/automatic gain control, AGC, physical side link control channel, PSCCH, training RS, and physical side link shared channel, PSCCH.

29. The user equipment of claim 28, wherein the PSCCH carries at least a portion of a source identification of the at least one second user equipment, a beam index number for the at least one TRS, a resource allocation and size of the at least one TRS within the TTI, a power offset of a beam transmission of the at least one TRS, an absolute power of the beam transmission of the at least one TRS, and a resource allocation of the PSCCH within the TTI.

30. The user equipment of claim 29, wherein the source identification is a Media Access Control (MAC) layer address.

31. The user equipment of claim 29, wherein the power offset indicates a difference between Min { P _ powerclass, P _ cmax } and an actual TRS transmit power, wherein P _ powerclass is a power class level for the at least one second user equipment for a communication band, and P _ cmax is a maximum output power configured for a serving cell when in network coverage or a maximum output power preconfigured when outside of the network coverage.

32. The user equipment of claim 31, wherein a zero power offset implies a maximum power level allowed by the network for TRS transmissions.

33. The user equipment of claim 32, wherein the maximum power level is configured for use during an initial group communication over the sidelink interface or in a queuing operation by the user equipment for the at least one second user equipment.

34. The user equipment of claim 31, wherein non-zero power offset means a power lower than the maximum power level.

35. The user equipment of claim 26, wherein the burst set of the at least one TRS in the compressed beam scanning mode is applied for an entire transmission of a transmission time interval TTI and includes a guard period GP/automatic gain control AGC region, a PSCCH carrying sidelink control information SCI for scheduling the at least one TRS, and a TRS beam scanning region.

36. The user equipment of claim 35, wherein the SCI comprises at least a portion of a source identification, a number of the at least one TRS within the burst set of the at least one TRS in the compressed beam scanning mode, a power offset of a beam transmission of the at least one TRS, an absolute power of the beam transmission of the at least one TRS, a processing gap length, and beam feedback.

37. The user equipment of claim 36, wherein the source identification is a Media Access Control (MAC) layer address.

38. The user equipment of claim 37, wherein the power offset indicates a difference between Min { P _ powerclass, P _ cmax } and an actual TRS transmit power, wherein P _ powerclass is a power class level for the at least one second user equipment for a communication band, and P _ cmax is a maximum output power configured for a serving cell when in network coverage or a maximum output power preconfigured when outside of the network coverage.

39. The user equipment of claim 38, wherein a zero power offset implies a maximum power level allowed by the network for TRS transmissions.

40. The user equipment of claim 39, wherein the maximum power level is configured for use during an initial group communication over the sidelink interface or in a queuing operation by the user equipment for the at least one second user equipment.

41. The user equipment of claim 38, wherein non-zero power offset means a power lower than the maximum power level.

42. The user equipment of claim 36, wherein the number of the at least one TRS within the set of bursts of the at least one TRS in the compressed beam scanning mode corresponds to a number of beam scanning directions.

43. The user equipment of claim 36, wherein the SCI further indicates at least one of a gap region and a feedback region.

44. The user equipment of claim 36, wherein the processor is further configured to derive a path loss measurement for the optimal beam scan direction from the at least one second user equipment.

45. The user equipment of claim 44, wherein the processor is further configured to derive the path loss measurement according to at least one of the following equations:

path L oss (P L) ═ Min { P _ powerclass, P _ cmax } -power _ offset-RSRP, or

PathLoss(PL)＝Min{P_powerclass,P_cmax}–power_offset–RSSI，

Wherein power _ offset indicates a difference between Min { P _ powerclass, P _ cmax } and an actual TRS transmit power, P _ powerclass being a power class level for the at least one second user equipment of the communication band, P _ cmax being a maximum output power configured for a serving cell when in network coverage or a maximum output power preconfigured when outside the network coverage.

46. The user equipment of claim 45, wherein the processor is further configured to determine a Modulation and Coding Scheme (MCS) level for a next transmission from the at least one second user equipment based on the path loss measurement.

47. The user equipment of claim 46, wherein the processor is further configured to determine the MCS level for the next transmission from the at least one second user equipment based on a highest path loss measurement.

48. The user equipment of claim 47, wherein the processor is further configured to maintain a data buffer of the user equipment at a minimum level and to determine a highest MCS based on a respective power of the at least second user equipment such that MCS < ═ Min { P _ powerclass, P _ cmax }.

49. The user equipment of claim 46, wherein the processor is further configured to set an output power level for the at least one second user equipment for the next transmission based on the MCS level and the path loss measurement.

50. A method of wireless communication of a user equipment, comprising:

periodically performing beam scanning of at least one tracking reference signal TRS in different spatial directions in the burst set towards the at least one second user equipment.

51. The method of claim 50, further comprising receiving reporting information from the at least one second user equipment, the reporting information comprising at least one of information related to the selected optimal beam scanning direction and information related to a setting of a transmission parameter.

52. The method of claim 50, further comprising periodically performing the beam scanning of the at least one TRS toward the at least one second user equipment in the different spatial directions in the burst set according to at least one of a travel speed of the user equipment and a frequency interval of a transmission carrier.

53. The method of claim 50, wherein the set of bursts of the at least one TRS comprises at least one of a full beam scan pattern and a compressed beam scan pattern.

54. The method of claim 53, wherein the set of bursts of the at least one TRS are in the full beam scan mode, each beam scan direction is applied to an entire transmission of a Transmission Time Interval (TTI), and a duration of the set of bursts of the at least one TRS is a number of beam scan directions multiplied by a length of the TTI.

55. The method of claim 54, wherein the TTI for each beam scanning direction comprises a guard period GP/automatic gain control (AG) region, a physical side link control channel (PSCCH, training RS, and physical side link shared channel (PSSCH).

56. The method of claim 55, wherein the PSCCH carries at least a portion of a source identification of the user equipment, a beam index number for the at least one TRS, a resource allocation and size of the at least one TRS within the TTI, a power offset of a beam transmission of the at least one TRS, an absolute power of the beam transmission of the at least one TRS, and a resource allocation of the PSSCH within the TTI.

57. The method of claim 56, wherein the source identification is a Media Access Control (MAC) layer address.

58. The method of claim 56, wherein the power offset indicates a difference between Min { P _ powerclass, P _ cmax } and an actual TRS transmit power, wherein P _ powerclass is a power class level of the user equipment for a communication band, and P _ cmax is a maximum output power configured for a serving cell when in network coverage or a maximum output power preconfigured when outside of the network coverage.

59. The method of claim 58, wherein a zero power offset implies a maximum power level allowed by a network for TRS transmissions.

60. The method of claim 59, wherein the maximum power level is configured for use during an initial group communication over the sidelink interface or in a queuing operation by the user equipment for the at least one second user equipment.

61. The method of claim 58, wherein a non-zero power offset implies a power lower than the maximum power level.

62. The method of claim 53, wherein the burst set of the at least one TRS in the compressed beam scanning mode is applied for an entire transmission of a Transmission Time Interval (TTI) and comprises a Guard Period (GP)/Automatic Gain Control (AGC) region, a PSCCH carrying Sidelink Control Information (SCI) used for scheduling the at least one TRS, and a TRS beam scanning region.

63. The method of claim 62, wherein the SCI comprises at least a portion of a source identification of the user equipment, a number of the at least one TRS within the burst set of the at least one TRS in the compressed beam scanning mode, a power offset of a beam transmission of the at least one TRS, an absolute power of the beam transmission of the at least one TRS, a processing gap length, and beam feedback.

64. The method of claim 63, wherein the source identification is a Media Access Control (MAC) layer address.

65. The method of claim 63, wherein the power offset indicates a difference between Min { P _ powerclass, P _ cmax } and an actual TRS transmit power, wherein P _ powerclass is a power class level of the user equipment for a communication band, and P _ cmax is a maximum output power configured for a serving cell when in network coverage or a maximum output power preconfigured when outside of the network coverage.

66. The method of claim 65, wherein a zero power offset implies a maximum power level allowed by the network for TRS transmissions.

67. The method of claim 66, wherein the maximum power level is configured for use during an initial group communication over the sidelink interface or in a queuing operation by the user equipment for the at least one second user equipment.

68. The method of claim 65, wherein a non-zero power offset implies a power lower than the maximum power level.

69. The method of claim 63, wherein the number of the at least one TRS within the set of bursts of the at least one TRS in the compressed beam scanning mode corresponds to a number of beam scanning directions.

70. The method of claim 63, wherein the SCI further indicates at least one of a gap region and a feedback region.

71. A method of wireless communication of a user equipment, comprising:

72. The method of claim 71, further comprising determining the optimal beam scanning direction for transmissions towards the at least one second user equipment based on at least one of an estimated time of arrival (ToA), angle of arrival (AoA), and direction of arrival (DoA) of the optimal beam scanning direction from the at least one second user equipment.

73. The method of claim 72, wherein the at least one second user equipment is at least two in number, the optimal beam scanning direction towards one second user equipment is also the optimal beam scanning direction for another second user equipment.

74. The method of claim 71, further comprising transmitting reporting information to the at least one second user equipment, the reporting information comprising at least one of information related to the optimal beam scanning direction and information related to a setting of a transmission parameter.

75. The method of claim 71, wherein the set of bursts of the at least one TRS comprises at least one of a full beam scan pattern and a compressed beam scan pattern.

76. The method of claim 75, wherein the set of bursts of the at least one TRS are in the full beam scan mode, each beam scan direction is applied to an entire transmission of a Transmission Time Interval (TTI), and a duration of the set of bursts of the at least one TRS is a number of beam scan directions multiplied by a length of the TTI.

77. The method of claim 76, wherein the TTI for each beam scanning direction comprises a guard period GP/Automatic Gain Control (AGC) region, a Physical Sidelink Control Channel (PSCCH), a training RS, and a Physical Sidelink Shared Channel (PSSCH).

78. The method of claim 77, wherein the PSCCH carries at least a portion of a source identification of the at least one second user equipment, a beam index number for the at least one TRS, a resource allocation and size of the at least one TRS within the TTI, a power offset of a beam transmission of the at least one TRS, an absolute power of the beam transmission of the at least one TRS, and a resource allocation of the PSSCH within the TTI.

79. The method of claim 78, wherein the source identification is a Media Access Control (MAC) layer address.

80. The method of claim 78, wherein the power offset indicates a difference between Min { P _ powerclass, P _ cmax } and an actual TRS transmit power, wherein P _ powerclass is a power class level for the at least one second user equipment for a communication band, and P _ cmax is a maximum output power configured for a serving cell when in network coverage or a maximum output power preconfigured when outside of the network coverage.

81. The method of claim 80, wherein a zero power offset implies a maximum power level allowed by the network for TRS transmissions.

82. The method of claim 81, wherein the maximum power level is configured for use during an initial group communication over the sidelink interface or in a queuing operation by the user equipment for the at least one second user equipment.

83. The method of claim 80, wherein a non-zero power offset implies a power lower than the maximum power level.

84. The method of claim 75, wherein the burst set of the at least one TRS in the compressed beam scanning mode is applied for an entire transmission of a Transmission Time Interval (TTI) and comprises a Guard Period (GP)/Automatic Gain Control (AGC) region, a PSCCH carrying Sidelink Control Information (SCI) used for scheduling the at least one TRS, and a TRS beam scanning region.

85. The method of claim 84, wherein the SCI comprises at least a portion of a source identification, a number of the at least one TRS within the set of bursts of the at least one TRS in the compressed beam scanning mode, a power offset of a beam transmission of the at least one TRS, an absolute power of the beam transmission of the at least one TRS, a processing gap length, and beam feedback.

86. The method of claim 85, wherein the source identification is a Media Access Control (MAC) layer address.

87. The method of claim 86, wherein the power offset indicates a difference between Min { P _ powerclass, P _ cmax } and an actual TRS transmit power, wherein P _ powerclass is a power class level for the at least one second user equipment for a communication band, and P _ cmax is a maximum output power configured for a serving cell when in network coverage or a maximum output power preconfigured when outside of the network coverage.

88. The method of claim 87, wherein a zero power offset implies a maximum power level allowed by the network for TRS transmissions.

89. The method of claim 88, wherein the maximum power level is configured for use during an initial group communication over the sidelink interface or in a queuing operation by the user equipment for the at least one second user equipment.

90. The method of claim 87, wherein a non-zero power offset implies a power lower than the maximum power level.

91. The method of claim 85, wherein the number of the at least one TRS within the set of bursts of the at least one TRS in the compressed beam scanning mode corresponds to a number of beam scanning directions.

92. The method of claim 85 wherein the SCI further indicates at least one of a gap region and a feedback region.

93. The method of claim 85, further comprising deriving a path loss measurement for the optimal beam scan direction from the at least one second user equipment.

94. The method of claim 93, further comprising deriving the path loss measurement according to at least one of the following equations:

path L oss (P L) ═ Min { P _ powerclass, P _ cmax } -power _ offset-RSRP, or

PathLoss(PL)＝Min{P_powerclass,P_cmax}–power_offset–RSSI，

95. The method of claim 94, further comprising determining a modulation and coding scheme, MCS, level for a next transmission from the at least one second user equipment based on the path loss measurements.

96. The method of claim 95, further comprising determining the MCS level for the next transmission from the at least one second user equipment based on a highest path loss measurement.

97. The method of claim 96, further comprising maintaining a data buffer for the user equipment at a minimum level and determining a highest MCS based on a respective power of the at least second user equipment such that MCS < ═ Min { P _ power class, P _ cmax }.

98. The method of claim 95, further comprising setting an output power level for the at least one second user equipment for the next transmission based on the MCS level and the path loss measurement.

99. A user equipment for wireless communication, comprising:

a memory; and

a processor coupled to the memory and configured to:

receiving, from the at least one second user equipment, at least one tracking reference signal, TRS, in different spatial directions in a burst set of TRSs; and

selecting an optimal beam scanning direction, wherein the set of bursts of the at least one TRS are in a full beam scanning mode, each beam scanning direction is applied to an entire transmission of a transmission time interval, TTI, and a duration of the set of bursts of the at least one TRS is a number of beam scanning directions multiplied by a length of the TTI.

100. The user equipment of claim 99, wherein the TTI for each beam scanning direction comprises a guard period GP/automatic gain control, AGC, region, a physical side link control channel, PSCCH, a training RS, and a physical side link shared channel, PSCCH.

101. The user equipment of claim 100, wherein the PSCCH carries at least a portion of a source identification of the at least one second user equipment, a beam index number for the at least one TRS, a resource allocation and size of the at least one TRS within the TTI, a power offset of a beam transmission of the at least one TRS, an absolute power of the beam transmission of the at least one TRS, and a resource allocation of the PSCCH within the TTI.

102. The user equipment of claim 101, wherein the source identification is a Media Access Control (MAC) layer address.

103. The user equipment of claim 101, wherein the power offset indicates a difference between Min { P _ powerclass, P _ cmax } and an actual TRS transmit power, wherein P _ powerclass is a power class level for the at least one second user equipment for a communication band, and P _ cmax is a maximum output power configured for a serving cell when in network coverage or a maximum output power preconfigured when outside of the network coverage.

104. The user equipment of claim 102, wherein the zero power offset implies a maximum power level allowed by a network for TRS transmissions.

105. The user equipment of claim 103, wherein the maximum power level is configured for use during an initial group communication over the sidelink interface or in a queuing operation by the user equipment for the at least one second user equipment.

106. The user equipment of claim 102, wherein non-zero power offset implies a lower power than the maximum power level.

107. A user equipment for wireless communication, comprising:

a memory; and

a processor coupled to the memory and configured to:

selecting an optimal beam scanning direction, wherein the burst set of the at least one TRS is in a compressed beam scanning mode and comprises a guard period GP)/automatic gain control AGC field, a PSCCH carrying sidelink control information SCI for scheduling the at least one TRS, and a TRS beam scanning field.

108. The user equipment of claim 106, wherein the SCI comprises at least a portion of a source identification, a number of the at least one TRS within the burst set of the at least one TRS in the compressed beam scanning mode, a power offset of a beam transmission of the at least one TRS, an absolute power of the beam transmission of the at least one TRS, a processing gap length, and beam feedback.

109. The user equipment of claim 107, wherein the source identification is a Media Access Control (MAC) layer address.

110. The user equipment of claim 108, wherein the power offset indicates a difference between Min { P _ powerclass, P _ cmax } and an actual TRS transmit power, wherein P _ powerclass is a power class level for the at least one second user equipment for a communication band, and P _ cmax is a maximum output power configured for a serving cell when in network coverage or a maximum output power preconfigured when outside of the network coverage.

111. The user equipment of claim 109, wherein a zero power offset implies a maximum power level allowed by the network for TRS transmissions.

112. The user equipment of claim 110, wherein the maximum power level is configured for use during an initial group communication over the sidelink interface or in a queuing operation by the user equipment for the at least one second user equipment.

113. The user equipment of claim 109, wherein non-zero power offset implies a lower power than the maximum power level.

114. The user equipment of claim 107, wherein the number of the at least one TRS within the set of bursts of the at least one TRS in the compressed beam scanning mode corresponds to a number of beam scanning directions.

115. The user equipment of claim 107 wherein the SCI further indicates at least one of a gap region and a feedback region.