WO2019148455A1

WO2019148455A1 - User equipment and method of wireless communication of same

Info

Publication number: WO2019148455A1
Application number: PCT/CN2018/075143
Authority: WO
Inventors: Huei-Ming Lin; Hai Tang
Original assignee: Guangdong Oppo Mobile Telecommunications Corp., Ltd.
Priority date: 2018-02-02
Filing date: 2018-02-02
Publication date: 2019-08-08
Also published as: CN116436504A; CN111480302B; CN111480302A

Abstract

A user equipment and a method of wireless communication of the same are provided. The user equipment includes a memory and a processor coupled to the memory. The processor is configured to perform a group communication over a sidelink interface to at least one second user equipment and periodically perform a beam sweeping of at least one tracking reference signal (TRS) in different spatial directions in a burst set of the at least one TRS toward the at least one second user equipment.

Description

USER EQUIPMENT AND METHOD OF WIRELESS COMMUNICATION OF SAME

BACKGROUND OF DISCLOSURE

1. Field of Disclosure

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

2. Description of Related Art

For future 5th generation new radio (5G-NR) mobile communication system, it has been decided that the 5G-NR system mobile communication may support wireless transmission and reception in super high frequency (SHF) spectrum and even extremely high frequency (EHF) spectrum such as mmW band, which is favorable for directional transceiver operations such as beamforming and multiple-input and multiple-output (MIMO) . Combining this with a trend of adoption of more antenna elements in user devices such as mobile phones and wireless equipment in vehicles, a recent design of 5G-NR for both downlink (DL) and uplink (UL) operations incorporated massive MIMO technology to enable “pencil-like” beams transmission through adoption of large number of antenna elements at base stations (BS) to boost signal coverage and increase data throughput.

For NR-sidelink technology via PC5 interface for direct user equipment-to-user equipment (UE-to-UE) discovery and communication without routing through BS, it is envisioned that MIMO and/or beamforming-like operation may also be supported to enhance system operation and to support more advanced use cases. However, in a current long term evolution (LTE) sidelink technology for device-to-device (D2D) communication and vehicle-to-everything (V2X) communication including vehicle-to-vehicle (V2V) , vehicle-to-pedestrian (V2P) , and vehicle-to-infrastructure/network (V2I/N) , MIMO and beamforming like operations are not supported. As such, sidelink signals and channels are being transmitted omnidirectional from each UE. Furthermore, the UEs are transmit at maximum allowable power regardless of channel type such as control channel or data channel, signal type such as synchronization signals or reference signals, operating condition such as in-network coverage or out-of-network coverage, and communication type such as broadcast, groupcast or unicast to achieve a maximum signal coverage and a communication range. For unicast and groupcast types of communication, it is rather power inefficient way of using UE’s battery power when a required communication range is much less than a signal coverage from transmitting at maximum allowable power. For example, when communicating UEs in a group are in close proximity such as 10’s of meters or directly adjacent to each other, relative speeds between UEs are low, or low transmission-rate/modulation and coding scheme (MCS) level. Additionally, signal transmission at a power level greater than a required power level would also increase interference to signal transmissions from other UEs that are outside a required communicating group, and thus, limiting a number of available resources that can be utilized by others.

SUMMARY

An object of the present disclosure is to propose a user equipment (UE) and a method of wireless communication of the same capable of performing beamforming operation and setting transmission related parameters for sidelink communication in a group environment.

In a first aspect of the present disclosure, a user equipment for wireless communication includes a memory and a processor coupled to the memory. The processor is configured to perform a group communication over a sidelink interface to at least one second user equipment and periodically perform a beam sweeping of at least one tracking reference signal (TRS) in different spatial directions in a burst set of the at least one TRS toward the at least one second user equipment.

According to an embodiment in conjunction to the first aspect of the present disclosure, the processor is further configured to receive, from the at least one second user equipment, report information including at least one of information related to a selected optimal beam sweeping direction and information related to a setting of transmission parameters.

According to an embodiment in conjunction to the first aspect of the present disclosure, the processor is configured to periodically perform the beam sweeping of the at least one TRS in the different spatial directions in the burst set of the at least one TRS toward the at least one second user equipment depending on at least one of a traveling speed of the user equipment and a tone spacing of a transmission carrier.

According to an embodiment in conjunction to the first aspect of the present disclosure, the burst set of the at least one TRS includes at least one of a full beam sweeping mode and a condense beam sweeping mode.

According to an embodiment in conjunction to the first aspect of the present disclosure, the burst set of the at least one TRS is in the full beam sweeping mode, each beam sweeping direction is applied to an entire transmission of a transmission time interval (TTI) , and a duration of the burst set of the at least one TRS is a number of beam sweeping directions times a length of the TTI.

According to an embodiment in conjunction to the first aspect of the present disclosure, the TTI for each beam sweeping direction includes 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) .

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

According to an embodiment in conjunction to the first aspect of the present disclosure, the source identity is a media access control (MAC) layer address.

According to an embodiment in conjunction to the first aspect of the present disclosure, 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 communicating frequency band, P_cmax is a configured maximum output power for a serving cell when in a network coverage or a pre-configured maximum output power when out of the network coverage.

According to an embodiment in conjunction to the first aspect of the present disclosure, a zero power offset means a maximum power level allowable by a network for a TRS transmission.

According to an embodiment in conjunction to the first aspect of the present disclosure, the maximum power level is configured for use during an initial group communication over the sidelink interface or in a platooning operation by the user equipment to the at least one second user equipment.

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

According to an embodiment in conjunction to the first aspect of the present disclosure, the burst set of the at least one TRS in the condense beam sweeping mode is applied to an 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 sweeping region.

According to an embodiment in conjunction to the first aspect of the present disclosure, the SCI includes at least a part of a source identity of the user equipment, a number of the at least one TRS within the burst set of the at least one TRS in the condense beam sweeping mode, a power offset of beam transmissions of the at least one TRS, an absolute power of the beam transmissions of the at least one TRS, a processing gap length, and a beam feedback.

According to an embodiment in conjunction to the first aspect of the present disclosure, the number of the at least one TRS within the burst set of the at least one TRS in the condense beam sweeping mode corresponds to a number of beam sweeping directions.

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

In a second aspect of the present disclosure, a user equipment for wireless communication includes a memory and a processor coupled to the memory. The processor is configured to perform a group communication over a sidelink interface to at least one second user equipment, receive at least one tracking reference signal (TRS) in different spatial directions in a burst set of the at least one TRS from the at least one second user equipment, calculate at least one of a reference signal received power (RSRP) and a received signal strength indicator (RSSI) for the at least one TRS in a burst set of the at least one TRS, and select an optimal beam sweeping direction based on at least one of an optimal RSRP result and an optimal RSSI result.

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

According to another embodiment in conjunction to the second aspect of the present disclosure, a number of the at least one second user equipment is at least two, the optimal beam sweeping direction towards one second user equipment is also the optimal beam sweeping direction for another second user equipment.

According to another embodiment in conjunction to the second aspect of the present disclosure, the processor is further configured to transmit, to the at least one second user equipment, report information including at least one of information related to the optimal beam sweeping direction and information related to a setting of transmission parameters.

According to another embodiment in conjunction to the second aspect of the present disclosure, the burst set of the at least one TRS includes at least one of a full beam sweeping mode and a condense beam sweeping mode.

According to another embodiment in conjunction to the second aspect of the present disclosure, the burst set of the at least one TRS is in the full beam sweeping mode, each beam sweeping direction is applied to an entire transmission of a transmission time interval (TTI) , and a duration of the burst set of the at least one TRS is a number of beam sweeping directions times a length of the TTI.

According to another embodiment in conjunction to the second aspect of the present disclosure, the TTI for each beam sweeping direction includes 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) .

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

According to another embodiment in conjunction to the second aspect of the present disclosure, the source identity is a media access control (MAC) layer address.

According to another embodiment in conjunction to the second aspect of the present disclosure, 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 at least one second user equipment for a communicating frequency band, P_cmax is a configured maximum output power for a serving cell when in a network coverage or a pre-configured maximum output power when out of the network coverage.

According to another embodiment in conjunction to the second aspect of the present disclosure, a zero power offset means a maximum power level allowable by a network for a TRS transmission.

According to another embodiment in conjunction to the second aspect of the present disclosure, the maximum power level is configured for use during an initial group communication over the sidelink interface or in a platooning operation by the user equipment to the at least one second user equipment.

According to another embodiment in conjunction to the second aspect of the present disclosure, a non-zero power offset means a lower power than the maximum power level.

According to another embodiment in conjunction to the second aspect of the present disclosure, the burst set of the at least one TRS in the condense beam sweeping mode is applied to an 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 sweeping region.

According to another embodiment in conjunction to the second aspect of the present disclosure, the SCI includes at least a part of a source identity, a number of the at least one TRS within the burst set of the at least one TRS in the condense beam sweeping mode, a power offset of beam transmissions of the at least one TRS, an absolute power of the beam transmissions of the at least one TRS, a processing gap length, and a beam feedback.

According to another embodiment in conjunction to the second aspect of the present disclosure, the number of the at least one TRS within the burst set of the at least one TRS in the condense beam sweeping mode corresponds to a number of beam sweeping directions.

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

According to another embodiment in conjunction to the second aspect of the present disclosure, the processor is further configured to derive a pathloss measurement for the optimal beam sweeping direction from the at least one second user equipment.

According to another embodiment in conjunction to the second aspect of the present disclosure, the processor is further configured to derive the pathloss measurement according to at least one of the following equations:

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

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

where power_offset indicates a difference between Min {P_powerclass, P_cmax} and an actual TRS transmit power, P_powerclass is a power class level of the at least one second user equipment for a communicating frequency band, P_cmax is a configured maximum output power for a serving cell when in a network coverage or a pre-configured maximum output power when out of the network coverage.

According to another embodiment in conjunction to the second aspect of the present 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 pathloss measurement.

According to another embodiment in conjunction to the second aspect of the present 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 a highest pathloss measurement.

According to another embodiment in conjunction to the second aspect of the present disclosure, the processor is further configured to keep a data buffering of the user equipment at a minimal level and determine the highest MCS based on a corresponding power of the at least second user equipment, such that MCS <= Min {P_powerclass, P_cmax} .

According to another embodiment in conjunction to the second aspect of the present disclosure, 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 pathloss measurement.

In a third aspect of the present disclosure, a method of wireless communication of a user equipment includes performing a group communication over a sidelink interface to at least one second user equipment and periodically performing a beam sweeping of at least one tracking reference signal (TRS) in different spatial directions in a burst set of the at least one TRS toward the at least one second user equipment.

According to another embodiment in conjunction to the third aspect of the present disclosure, the method further includes receiving, from the at least one second user equipment, report information including at least one of information related to a selected optimal beam sweeping direction and information related to a setting of transmission parameters.

According to another embodiment in conjunction to the third aspect of the present disclosure, the method further includes periodically performing the beam sweeping of the at least one TRS in the different spatial directions in the burst set of the at least one TRS toward the at least one second user equipment depending on at least one of a traveling speed of the user equipment and a tone spacing of a transmission carrier.

According to another embodiment in conjunction to the third aspect of the present disclosure, the burst set of the at least one TRS includes at least one of a full beam sweeping mode and a condense beam sweeping mode.

According to another embodiment in conjunction to the third aspect of the present disclosure, the burst set of the at least one TRS is in the full beam sweeping mode, each beam sweeping direction is applied to an entire transmission of a transmission time interval (TTI) , and a duration of the burst set of the at least one TRS is a number of beam sweeping directions times a length of the TTI.

According to another embodiment in conjunction to the third aspect of the present disclosure, the TTI for each beam sweeping direction includes 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) .

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

According to another embodiment in conjunction to the third aspect of the present disclosure, the source identity is a media access control (MAC) layer address.

According to another embodiment in conjunction to the third aspect of the present disclosure, 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 communicating frequency band, P_cmax is a configured maximum output power for a serving cell when in a network coverage or a pre-configured maximum output power when out of the network coverage.

According to another embodiment in conjunction to the third aspect of the present disclosure, a zero power offset means a maximum power level allowable by a network for a TRS transmission.

According to another embodiment in conjunction to the third aspect of the present disclosure, the maximum power level is configured for use during an initial group communication over the sidelink interface or in a platooning operation by the user equipment to the at least one second user equipment.

According to another embodiment in conjunction to the third aspect of the present disclosure, a non-zero power offset means a lower power than the maximum power level.

According to another embodiment in conjunction to the third aspect of the present disclosure, the method further the burst set of the at least one TRS in the condense beam sweeping mode is applied to an 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 sweeping region.

According to another embodiment in conjunction to the third aspect of the present disclosure, the SCI includes at least a part of a source identity of the user equipment, a number of the at least one TRS within the burst set of the at least one TRS in the condense beam sweeping mode, a power offset of beam transmissions of the at least one TRS, an absolute power of the beam transmissions of the at least one TRS, a processing gap length, and a beam feedback.

According to another embodiment in conjunction to the third aspect of the present disclosure, the number of the at least one TRS within the burst set of the at least one TRS in the condense beam sweeping mode corresponds to a number of beam sweeping directions.

According to another embodiment in conjunction to the third aspect of the present 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 a group communication over a sidelink interface to at least one second user equipment, receiving at least one tracking reference signal (TRS) in different spatial directions in a burst set of the at least one TRS from the at least one second user equipment, calculating at least one of a reference signal received power (RSRP) and a received signal strength indicator (RSSI) for the at least one TRS in a burst set of the at least one TRS, and selecting an optimal beam sweeping direction based on at least one of an optimal RSRP result and an optimal RSSI result.

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

According to another embodiment in conjunction to the fourth aspect of the present disclosure, a number of the at least one second user equipment is at least two, the optimal beam sweeping direction towards one second user equipment is also the optimal beam sweeping direction for another second user equipment.

According to another embodiment in conjunction to the fourth aspect of the present disclosure, the method further includes transmitting, to the at least one second user equipment, report information including at least one of information related to the optimal beam sweeping direction and information related to a setting of transmission parameters.

According to another embodiment in conjunction to the fourth aspect of the present disclosure, the burst set of the at least one TRS includes at least one of a full beam sweeping mode and a condense beam sweeping mode.

According to another embodiment in conjunction to the fourth aspect of the present disclosure, the burst set of the at least one TRS is in the full beam sweeping mode, each beam sweeping direction is applied to an entire transmission of a transmission time interval (TTI) , and a duration of the burst set of the at least one TRS is a number of beam sweeping directions times a length of the TTI.

According to another embodiment in conjunction to the fourth aspect of the present disclosure, the TTI for each beam sweeping direction includes 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) .

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

According to another embodiment in conjunction to the fourth aspect of the present disclosure, the source identity is a media access control (MAC) layer address.

According to another embodiment in conjunction to the fourth aspect of the present disclosure, 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 at least one second user equipment for a communicating frequency band, P_cmax is a configured maximum output power for a serving cell when in a network coverage or a pre-configured maximum output power when out of the network coverage.

According to another embodiment in conjunction to the fourth aspect of the present disclosure, a zero power offset means a maximum power level allowable by a network for a TRS transmission.

According to another embodiment in conjunction to the fourth aspect of the present disclosure, the maximum power level is configured for use during an initial group communication over the sidelink interface or in a platooning operation by the user equipment to the at least one second user equipment.

According to another embodiment in conjunction to the fourth aspect of the present disclosure, a non-zero power offset means a lower power than the maximum power level.

According to another embodiment in conjunction to the fourth aspect of the present disclosure, the burst set of the at least one TRS in the condense beam sweeping mode is applied to an 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 sweeping region.

According to another embodiment in conjunction to the fourth aspect of the present disclosure, the SCI includes at least a part of a source identity, a number of the at least one TRS within the burst set of the at least one TRS in the condense beam sweeping mode, a power offset of beam transmissions of the at least one TRS, an absolute power of the beam transmissions of the at least one TRS, a processing gap length, and a beam feedback.

According to another embodiment in conjunction to the fourth aspect of the present disclosure, the number of the at least one TRS within the burst set of the at least one TRS in the condense beam sweeping mode corresponds to a number of beam sweeping directions.

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

According to another embodiment in conjunction to the fourth aspect of the present disclosure, the method further includes deriving a pathloss measurement for the optimal beam sweeping direction from the at least one second user equipment.

According to another embodiment in conjunction to the fourth aspect of the present disclosure, the method further includes deriving the pathloss measurement according to at least one of the following equations:

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

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

According to another embodiment in conjunction to the fourth aspect of the present disclosure, the method further includes determining a modulation and coding scheme (MCS) level for a next transmission from the at least one second user equipment based on the pathloss measurement.

According to another embodiment in conjunction to the fourth aspect of the present disclosure, the method further includes determining the MCS level for the next transmission from the at least one second user equipment based on a highest pathloss measurement.

According to another embodiment in conjunction to the fourth aspect of the present disclosure, the method further includes keeping a data buffering of the user equipment at a minimal level and determining the highest MCS based on a corresponding power of the at least second user equipment, such that MCS <= Min {P_powerclass, P_cmax} .

According to another embodiment in conjunction to the fourth aspect of the present disclosure, the method further includes setting an output power level for the at least one second user equipment for the next transmission based on the MCS level and the pathloss measurement.

In a fifth aspect of the present disclosure, a user equipment for wireless communication includes a memory and a processor coupled to the memory. The processor is configured to perform a group communication over a sidelink interface to at least one second user equipment, receive at least one tracking reference signal (TRS) in different spatial directions in a burst set of the at least one TRS from the at least one second user equipment, and select an optimal beam sweeping direction, wherein the burst set of the at least one TRS is in a full beam sweeping mode, each beam sweeping direction is applied to an entire transmission of a transmission time interval (TTI) , and a duration of the burst set of the at least one TRS is a number of beam sweeping directions times a length of the TTI.

According to another embodiment in conjunction to the fifth aspect of the present disclosure, the TTI for each beam sweeping direction includes 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) .

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

According to another embodiment in conjunction to the fifth aspect of the present disclosure, the source identity is a media access control (MAC) layer address.

According to another embodiment in conjunction to the fifth aspect of the present disclosure, 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 at least one second user equipment for a communicating frequency band, P_cmax is a configured maximum output power for a serving cell when in a network coverage or a pre-configured maximum output power when out of the network coverage.

According to another embodiment in conjunction to the fifth aspect of the present disclosure, a zero power offset means a maximum power level allowable by a network for a TRS transmission.

According to another embodiment in conjunction to the fifth aspect of the present disclosure, the maximum power level is configured for use during an initial group communication over the sidelink interface or in a platooning operation by the user equipment to the at least one second user equipment.

According to another embodiment in conjunction to the fifth aspect of the present disclosure, a non-zero power offset means a lower power than the maximum power level.

In a sixth aspect of the present disclosure, a user equipment for wireless communication includes a memory and a processor coupled to the memory. The processor is configured to perform a group communication over a sidelink interface to at least one second user equipment, receive at least one tracking reference signal (TRS) in different spatial directions in a burst set of the at least one TRS from the at least one second user equipment, and select an optimal beam sweeping direction, wherein the burst set of the at least one TRS is in a condense beam sweeping 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 sweeping region.

According to another embodiment in conjunction to the sixth aspect of the present disclosure, the SCI includes at least a part of a source identity, a number of the at least one TRS within the burst set of the at least one TRS in the condense beam sweeping mode, a power offset of beam transmissions of the at least one TRS, an absolute power of the beam transmissions of the at least one TRS, a processing gap length, and a beam feedback.

According to another embodiment in conjunction to the sixth aspect of the present disclosure, the source identity is a media access control (MAC) layer address.

According to another embodiment in conjunction to the sixth aspect of the present disclosure, 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 at least one second user equipment for a communicating frequency band, P_cmax is a configured maximum output power for a serving cell when in a network coverage or a pre-configured maximum output power when out of the network coverage.

According to another embodiment in conjunction to the sixth aspect of the present disclosure, a zero power offset means a maximum power level allowable by a network for a TRS transmission.

According to another embodiment in conjunction to the sixth aspect of the present disclosure, the maximum power level is configured for use during an initial group communication over the sidelink interface or in a platooning operation by the user equipment to the at least one second user equipment.

According to another embodiment in conjunction to the sixth aspect of the present disclosure, a non-zero power offset means a lower power than the maximum power level.

According to another embodiment in conjunction to the sixth aspect of the present disclosure, the number of the at least one TRS within the burst set of the at least one TRS in the condense beam sweeping mode corresponds to a number of beam sweeping directions.

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

In the embodiment of the present disclosure, the user equipment and the method of wireless communication of the same are capable of performing beamforming operation and setting transmission related parameters for sidelink communication in a group environment, such that the user equipment could save battery, perform long operation time, and/or have good operating performance from less interference.

BRIEF DESCRIPTION OF DRAWINGS

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

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 flowchart illustrating a method of wireless communication according to the present disclosure, from an aspect of operation of a user equipment for transmitting signals.

FIG. 3 is a flowchart illustrating a method of wireless communication according to the present disclosure, from an aspect of operation of a user equipment for receiving signals.

FIG. 4 is a diagram of a beam sweeping 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 is in a full beam sweeping mode according to an embodiment of the present disclosure.

FIG. 6 is a diagram of a burst set of at least one TRS is in a condense beam sweeping mode according to an embodiment of the present disclosure.

FIG. 7 is a scenario of a plurality of user equipments participating in a sidelink group communication according to an embodiment of the present disclosure.

DETAILED DESCRIPTION OF EMBODIMENTS

Embodiments of the present disclosure are described in detail with the technical matters, structural features, achieved objects, and effects with reference to the accompanying drawings as follows. Specifically, the terminologies in the embodiments of the present disclosure are merely for describing the purpose of the certain embodiment, but not to limit the 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 a group communication over a sidelink interface such as a PC5 interface to at least one user equipment 200 and periodically perform a beam sweeping of at least one tracking reference signal (TRS) in different spatial directions in a burst set of the at least one TRS toward the at least one user equipment 200, such that the at least one user equipment 100 could save battery, perform long operation time, and/or have good operating performance from less interference. The at least one user equipment 100 may be a user equipment for transmitting signals and the at least one user equipment 200 may be a user equipment for receiving signals. In some embodiments, the group communication between the at least one user equipment 100 and the at least one user equipment 200 over the sidelink interface such as the PC5 interface could be based on LTE sidelink technology developed under 3rd generation partnership project (3GPP) in Release 14 and/or 5th generation new radio 5G-NR radio access technology.

FIG. 1 further illustrates that, in some embodiments, the 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 a group communication over a sidelink interface such as a PC5 interface with the at least one user equipment 100, receive at least one tracking reference signal (TRS) in different spatial directions in a burst set of the at least one TRS from the at least one user equipment 100, calculate at least one of a reference signal received power (RSRP) and a received signal strength indicator (RSSI) for the at least one TRS in a burst set of the at least one TRS, and select an optimal beam sweeping direction based on at least one of an optimal RSRP result and an optimal RSSI result, such that the at least one user equipment 100 could save battery, perform long operation time, and/or have good operating performance from less interference.

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

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

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

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

where power_offset indicates a difference between Min {P_powerclass, P_cmax} and an actual TRS transmit power, P_powerclass is a power class level of the at least one user equipment 100 for a communicating frequency band, P_cmax is a configured maximum output power for a serving cell when in a network coverage or a pre-configured maximum output power when out of the 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 pathloss measurement. The processor 204 is further configured to determine the MCS level for the next transmission from the at least one user equipment 100 based on a highest pathloss measurement. The processor 204 is further configured to keep a data buffering of the user equipment 200 at a minimal level and determine the highest MCS based on a corresponding power of the at least 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 pathloss measurement.

In some embodiments, the

memories

102 and 202 each may include read-only memory (ROM) , random access memory (RAM) , flash memory, memory card, storage medium and/or other storage device. The

processors

104 and 204 each may include application-specific integrated circuit (ASIC) , other chipset, logic circuit and/or data processing device. The

processors

104 and 204 each 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. The modules can be stored in

memories

102 and 202 and executed by

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 those 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 relates to vehicle-to-everything (V2X) communication including vehicle-to-vehicle (V2V) , vehicle-to-pedestrian (V2P) , and vehicle-to-infrastructure/network (V2I/N) according to LTE sidelink technology developed under 3GPP in Release 14 and/or 5G-NR radio access technology.

FIG. 2 illustrates that, a method 300 of wireless communication according to the present disclosure, from an aspect of operation of the user equipment 100 for transmitting signals. The method 300 includes: at block 302, performing a group communication over a sidelink interface as a PC 5 interface to at least one user equipment 200, and at block 304, periodically performing a beam sweeping of at least one tracking reference signal (TRS) in different spatial directions in a burst set of the at least one TRS toward the at least one user equipment 200, such that the at least one user equipment 100 could save battery, perform long operation time, and/or have good operating performance from less interference.

FIG. 3 illustrates a method 400 of wireless communication according to the present disclosure, from an aspect of operation of the user equipment 200 for receiving signals. The method 400 includes: at block 402, performing a group communication over a sidelink interface such as a PC 5 interface to the at least one user equipment 100, at block 404, receiving at least one tracking reference signal (TRS) in different spatial directions in a burst set of the at least one TRS 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 indicator (RSSI) for the at least one TRS in a burst set of the at least one TRS, and at block 408, selecting an optimal beam sweeping direction based on at least one of an optimal RSRP result and an optimal RSSI result, such that the at least one user equipment 100 could save battery, perform long operation time, and/or have good operating performance from less interference.

FIG. 1 and FIGS. 4 to 6 illustrate that, in some embodiments, the processor 104 is further configured to receive, from the at least one user equipment 200, report information including at least one of information related to a selected optimal beam sweeping direction and information related to a setting of transmission parameters. The processor 104 is configured to periodically perform the beam sweeping of the at least one TRS in the different spatial directions in the burst set of the at least one TRS toward the at least one user equipment 200 depending on at least one of a traveling speed of the at least one user equipment 100 and a tone spacing of a transmission carrier. For example, the processor 104 is configured to perform the beam sweeping of the at least one TRS at every periodic interval such as 5ms, 10ms, 20ms, 50ms, and 100ms. The different spatial directions may be such as 4, 8, 16, 32, and 64 directions. The burst set of the at least one TRS includes at least one of a full beam sweeping mode as illustrated in FIG. 5 and a condense beam sweeping mode as illustrated in FIG. 6.

FIG. 1 and FIG. 5 illustrate that, in some embodiments, the burst set of the at least one TRS is in the full beam sweeping mode. Each beam sweeping direction is applied to an entire transmission of a transmission time interval (TTI) . A duration of the burst set of the at least one TRS is a number of beam sweeping directions times a length of the TTI. The TTI for each beam sweeping direction includes 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) . The PSCCH carries at least a part of a source identity of the user equipment 100, a beam index number for the at least one TRS, a resource allocation and a size of the at least one TRS within the TTI, a power offset of beam transmissions of the at least one TRS, an absolute power of the beam transmissions of the at least one TRS, and a resource allocation of the PSSCH within the TTI. The training RS may occupy one or multiple orthogonal frequency division multiplex (OFDM) symbols. The PSSCH may carry information data transport block (TB) . The source identity is a media access control (MAC) layer address that uniquely identifies the user equipment 100 or a member number within the sidelink communicating group.

FIG. 1 and FIG. 5 further illustrate that, in some embodiments, 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 communicating frequency band, P_cmax is a configured maximum output power for a serving cell when in a network coverage or a pre-configured maximum output power when out of the network coverage. A zero power offset means a maximum power level allowable by a network for a TRS transmission. The maximum power level is configured for use during an initial group communication over the sidelink interface or in a platooning operation by the user equipment 100 to the at least one user equipment 200 to reach as many equipments as possible to notify and invite new group members join at any time. A non-zero power offset means a lower power than the maximum power level. The lower power level could be set based on past history/detection of other group members’TRS to limit a transmission range and thus creating less interference and power saving.

FIG. 1 and FIG. 6 illustrate that, in some embodiments, the burst set of the at least one TRS is in the condense beam sweeping mode. The burst set of the at least one TRS in the condense beam sweeping mode is applied to an 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 sweeping region. The SCI includes at least a part of a source identity of the user equipment 100, a number of the at least one TRS within the burst set of the at least one TRS in the condense beam sweeping mode, a power offset of beam transmissions of the at least one TRS, an absolute power of the beam transmissions of the at least one TRS, a processing gap length, and a beam feedback.

In some embodiments, the source identity is a media access control (MAC) layer address that uniquely identifies the user equipment 100 or a member number within the sidelink communicating group. The processing gap length could be a fixed length based on number of OFDM symbols. The user equipment 200 uses the gap period for RSRP/RSSI measurement and selection of the optimal beam. The beam feedback reports a region size and may assign resources to group members for multiplexing beam reports. The at least one TRS is repeated and transmitted in all supported spatial directions. The length of a TRS transmission may be as short as one OFDM symbol. If indicated in SCI, the gap region where the user equipment 200 can utilize the gap duration to calculate RSRP/RSSI measurement results for each transmitted TRS and select the optimal beam within the burst set. Based on number of TRS’s and length of each TRS transmission, a starting position for the gap region can be determined by the user equipment 200. If indicated in SCI, the feedback region is for beam reporting by the user equipment 200.

FIG. 1 and FIG. 6 further illustrate that, in some embodiments, 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 communicating frequency band, P_cmax is a configured maximum output power for a serving cell when in a network coverage or a pre-configured maximum output power when out of the network coverage. A zero power offset means a maximum power level allowable by a network for a TRS transmission. The maximum power level is configured for use during an initial group communication over the sidelink interface or in a platooning operation by the user equipment 100 to the at least one user equipment 200 to reach as many user equipments as possible to notify and invite new group members join at any time. A non-zero power offset means a lower power than the maximum power level. The lower power level could be set based on past history/detection of other group members’TRS to limit a transmission range and thus creating less interference and power saving. The number of the at least one TRS within the burst set of the at least one TRS in the condense beam sweeping mode corresponds to a number of beam sweeping directions. The SCI further indicates at least one of a gap region and a feedback region.

FIG. 7 illustrates that, in some embodiments, in every beam sweeping period of each transmitting user equipment, a receiving user equipment calculates RSRP or RSSI for each transmitted TRS within a burst set and selects an optimal beam based on an optimal RSRP/RSSI result such as the highest RSRP/RSSI result. As illustration example in FIG. 7, where there are six user equipments (UEs) participating in sidelink group communication and UE3 measures RSRP/RSSI of all received TRS from all UEs and selects beam 3 being an optimal beam from UE1, beam 4 being an optimal beam from UE2, beam 1 being an optimal beam from UE4, beam 2 being an optimal beam from UE5, and beam 3 being an optimal beam from UE6.

In some embodiments, based on estimated ToA, AoA and/or DoA of a selected optimal beam from each transmitting UE, the receiving UE determines suitable beam direction for a transmission towards each transmitting UE. Sometimes the suitable beam direction towards one UE may also be the optimal suitable beam direction for another UE. As illustration example in FIG. 7, UE3 determines beam 1 being an optimal suitable direction for transmitting towards UE4 and UE6, beam 2 being an optimal suitable direction for transmitting towards UE1 and UE5, and beam 3 being an optimal suitable direction for transmitting towards UE2.

In some embodiments, from each selected optimal beam’s RSRP/RSSI result and a corresponding power_offset indicated in SCI, the receiving UE derives pathloss measurement according to PathLoss (PL) = Min {P_powerclass, P_cmax} –power_offset –RSRP/RSSI. As illustration example in FIG. 7, UE 3 derives pathloss for a selected optimal beam from each UE. The pathloss for a selected optimal beam from each UE is assume as: PL for beam 3 from UE1 = 6dB, PL for beam 4 from UE2 = 3dB, PL for beam 1 from UE4 = 3dB, PL for beam 2 from UE5 = 4dB, and PL for beam 3 from UE6 = 8dB.

In some embodiments, among the calculated PL of the selected optimal beam for each transmitting UE (Tx UE) , the receiving UE (Rx UE ) determines a suitable MCS level for a next transmission to the group. That is, the Rx UE selects a MCS level corresponding to the highest PL link, such that a common MCS is used for a next groupcast transmission and decodable to all members in the group. At the same time, the Rx UE may also take into account of its own data buffer status so that data buffering is kept at a minimal level. Highest MCS level that can be selected/supported should be based on its corresponding Required_Rx_power, such that the Required_Rx_power (MCS) <= Min {P_powerclass, P_cmax} . As illustration example in FIG. 7, UE3 would select a MCS level that corresponds to the PL link of 8dB from UE6.

In some embodiments, based on the selected MCS level and the corresponding Required_Rx_power, the UE determines transmission power for each selected optimal beam direction according to P_Tx (beam x) = Required_Tx_power (MCS) + PL (selected optimal beam) . As illustration example in FIG. 7, assuming the highest MCS level for the PL link of 8dB from UE6 would require a Rx power level of 10dBm, then UE3 would set its output power level for each transmit beam as:

P_Tx (Beam 1 towards UE4 and UE6) = 10dBm + 8dB = 18dBm,

P_Tx (Beam 2 towards UE1 and UE5) = 10dBm + 6dB = 16dBm, and

P_Tx (Beam 3 towards UE2) = 10dBm + 3dB = 13dBm.

A person having ordinary skill in the art understands that each of the units, algorithm, and steps described and disclosed in the embodiments of the present disclosure are realized using electronic hardware or combinations of software for computers and electronic hardware. Whether the functions run in hardware or software depends on the condition of application and design requirement for a technical plan. A person having ordinary skill in the art can use different ways to realize the function for each specific application while such realizations should not go beyond the scope of the present disclosure.

It is understood by a person having ordinary skill in the art that he/she can refer to the working processes of the system, device, and unit in the above-mentioned embodiment since the working processes of the above-mentioned system, device, and unit are basically the same. For easy description and simplicity, these working processes will not be detailed.

It is understood that the disclosed system, device, and method in the embodiments of the present disclosure can be realized with other ways. The above-mentioned embodiments are exemplary only. The division of the units is merely based on logical functions while other divisions exist in realization. It is possible that a plurality of units or components are combined or integrated in another system. It is also possible that some characteristics are omitted or skipped. On the other hand, the displayed or discussed mutual coupling, direct coupling, or communicative coupling operate through some ports, devices, or units whether indirectly or communicatively by ways of electrical, mechanical, or other kinds of forms.

The units as separating components for explanation are or are not physically separated. The units for display are or are not physical units, that is, located in one place or distributed on a plurality of network units. Some or all of the units are used according to the purposes of the embodiments.

Moreover, each of the functional units in each of the embodiments can be integrated in one processing unit, physically independent, or integrated in one processing unit with two or more than two units.

If the software function unit is realized and used and sold as a product, it can be stored in a readable storage medium in a computer. Based on this understanding, the technical plan proposed by the present disclosure can be essentially or partially realized as the form of a software product. Or, one part of the technical plan beneficial to the conventional technology can be realized as the form of a software product. The software product in the computer is stored in a storage medium, including a plurality of commands for a computational device (such as a personal computer, a server, or a network device) to run all or some of the steps disclosed by the embodiments of the present disclosure. The storage medium includes a USB disk, a mobile hard disk, a read-only memory (ROM) , a random access memory (RAM) , a floppy disk, or other kinds of media capable of storing program codes.

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

Claims

A user equipment for wireless communication, comprising:

a memory; and

a processor coupled to the memory and configured to:

perform a group communication over a sidelink interface to at least one second user equipment; and

periodically perform a beam sweeping of at least one tracking reference signal (TRS) in different spatial directions in a burst set of the at least one TRS toward the at least one second user equipment.
The user equipment of claim 1, wherein the processor is further configured to receive, from the at least one second user equipment, report information comprising at least one of information related to a selected optimal beam sweeping direction and information related to a setting of transmission parameters.
The user equipment of claim 1, wherein the processor is configured to periodically perform the beam sweeping of the at least one TRS in the different spatial directions in the burst set of the at least one TRS toward the at least one second user equipment depending on at least one of a traveling speed of the user equipment and a tone spacing of a transmission carrier.
The user equipment of claim 1, wherein the burst set of the at least one TRS comprises at least one of a full beam sweeping mode and a condense beam sweeping mode.
The user equipment of claim 4, wherein the burst set of the at least one TRS is in the full beam sweeping mode, each beam sweeping direction is applied to an entire transmission of a transmission time interval (TTI) , and a duration of the burst set of the at least one TRS is a number of beam sweeping directions times a length of the TTI.
The user equipment of claim 5, wherein the TTI for each beam sweeping 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) .
The user equipment of claim 6, wherein the PSCCH carries at least a part of a source identity of the user equipment, a beam index number for the at least one TRS, a resource allocation and a size of the at least one TRS within the TTI, a power offset of beam transmissions of the at least one TRS, an absolute power of the beam transmissions of the at least one TRS, and a resource allocation of the PSSCH within the TTI.
The user equipment of claim 7, wherein the source identity is a media access control (MAC) layer address.
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 communicating frequency band, P_cmax is a configured maximum output power for a serving cell when in a network coverage or a pre-configured maximum output power when out of the network coverage.
The user equipment of claim 9, wherein a zero power offset means a maximum power level allowable by a network for a TRS transmission.
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 platooning operation by the user equipment to the at least one second user equipment.
The user equipment of claim 9, wherein a non-zero power offset means a lower power than the maximum power level.
The user equipment of claim 4, wherein the burst set of the at least one TRS in the condense beam sweeping mode is applied to an 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 sweeping region.
The user equipment of claim 13, wherein the SCI comprises at least a part of a source identity of the user equipment, a number of the at least one TRS within the burst set of the at least one TRS in the condense beam sweeping mode, a power offset of beam transmissions of the at least one TRS, an absolute power of the beam transmissions of the at least one TRS, a processing gap length, and a beam feedback.
The user equipment of claim 14, wherein the source identity is a media access control (MAC) layer address.
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, where P_powerclass is a power class level of the user equipment for a communicating frequency band, P_cmax is a configured maximum output power for a serving cell when in a network coverage or a pre-configured maximum output power when out of the network coverage.
The user equipment of claim 16, wherein a zero power offset means a maximum power level allowable by a network for a TRS transmission.
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 platooning operation by the user equipment to the at least one second user equipment.
The user equipment of claim 16, wherein a non-zero power offset means a lower power than the maximum power level.
The user equipment of claim 14, wherein the number of the at least one TRS within the burst set of the at least one TRS in the condense beam sweeping mode corresponds to a number of beam sweeping directions.
The user equipment of claim 14, wherein the SCI further indicates at least one of a gap region and a feedback region.
A user equipment for wireless communication, comprising:

a memory; and

a processor coupled to the memory and configured to:

perform a group communication over a sidelink interface to at least one second user equipment;

receive at least one tracking reference signal (TRS) in different spatial directions in a burst set of the at least one TRS from the at least one second user equipment;

calculate at least one of a reference signal received power (RSRP) and a received signal strength indicator (RSSI) for the at least one TRS in a burst set of the at least one TRS; and

select an optimal beam sweeping direction based on at least one of an optimal RSRP result and an optimal RSSI result.
The user equipment of claim 22, wherein the processor is further to configured to determine the optimal beam sweeping direction for transmission towards the at least one second user equipment based on at least one of an estimated time of arrival (ToA) , an angle of arrival (AoA) , and a direction of arrival (DoA) of the optimal beam sweeping direction from the at least one second user equipment.
The user equipment of claim 23, wherein a number of the at least one second user equipment is at least two, the optimal beam sweeping direction towards one second user equipment is also the optimal beam sweeping direction for another second user equipment.
The user equipment of claim 22, wherein the processor is further configured to transmit, to the at least one second user equipment, report information comprising at least one of information related to the optimal beam sweeping direction and information related to a setting of transmission parameters.
The user equipment of claim 22, wherein the burst set of the at least one TRS comprises at least one of a full beam sweeping mode and a condense beam sweeping mode.
The user equipment of claim 26, wherein the burst set of the at least one TRS is in the full beam sweeping mode, each beam sweeping direction is applied to an entire transmission of a transmission time interval (TTI) , and a duration of the burst set of the at least one TRS is a number of beam sweeping directions times a length of the TTI.
The user equipment of claim 27, wherein the TTI for each beam sweeping 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) .
The user equipment of claim 28, wherein the PSCCH carries at least a part of a source identity of the at least one second user equipment, a beam index number for the at least one TRS, a resource allocation and a size of the at least one TRS within the TTI, a power offset of beam transmissions of the at least one TRS, an absolute power of the beam transmissions of the at least one TRS, and a resource allocation of the PSSCH within the TTI.
The user equipment of claim 29, wherein the source identity is a media access control (MAC) layer address.
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, where P_powerclass is a power class level of the at least one second user equipment for a communicating frequency band, P_cmax is a configured maximum output power for a serving cell when in a network coverage or a pre-configured maximum output power when out of the network coverage.
The user equipment of claim 31, wherein a zero power offset means a maximum power level allowable by a network for a TRS transmission.
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 platooning operation by the user equipment to the at least one second user equipment.
The user equipment of claim 31, wherein a non-zero power offset means a lower power than the maximum power level.
The user equipment of claim 26, wherein the burst set of the at least one TRS in the condense beam sweeping mode is applied to an 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 sweeping region.
The user equipment of claim 35, wherein the SCI comprises at least a part of a source identity, a number of the at least one TRS within the burst set of the at least one TRS in the condense beam sweeping mode, a power offset of beam transmissions of the at least one TRS, an absolute power of the beam transmissions of the at least one TRS, a processing gap length, and a beam feedback.
The user equipment of claim 36, wherein the source identity is a media access control (MAC) layer address.
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, where P_powerclass is a power class level of the at least one second user equipment for a communicating frequency band, P_cmax is a configured maximum output power for a serving cell when in a network coverage or a pre-configured maximum output power when out of the network coverage.
The user equipment of claim 38, wherein a zero power offset means a maximum power level allowable by a network for a TRS transmission.
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 platooning operation by the user equipment to the at least one second user equipment.
The user equipment of claim 38, wherein a non-zero power offset means a lower power than the maximum power level.
The user equipment of claim 36, wherein the number of the at least one TRS within the burst set of the at least one TRS in the condense beam sweeping mode corresponds to a number of beam sweeping directions.
The user equipment of claim 36, wherein the SCI further indicates at least one of a gap region and a feedback region.
The user equipment of claim 36, wherein the processor is further configured to derive a pathloss measurement for the optimal beam sweeping direction from the at least one second user equipment.
The user equipment of claim 44, wherein the processor is further configured to derive the pathloss measurement according to at least one of the following equations:

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

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

where power_offset indicates a difference between Min {P_powerclass, P_cmax} and an actual TRS transmit power, P_powerclass is a power class level of the at least one second user equipment for a communicating frequency band, P_cmax is a configured maximum output power for a serving cell when in a network coverage or a pre-configured maximum output power when out of the network coverage.
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 pathloss measurement.
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 pathloss measurement.
The user equipment of claim 47, wherein the processor is further configured to keep a data buffering of the user equipment at a minimal level and determine the highest MCS based on a corresponding power of the at least second user equipment, such that MCS <=Min {P_powerclass, P_cmax} .
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 pathloss measurement.
A method of wireless communication of a user equipment, comprising:

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

periodically performing a beam sweeping of at least one tracking reference signal (TRS) in different spatial directions in a burst set toward the at least one second user equipment.
The method of claim 50, further comprising receiving, from the at least one second user equipment, report information comprising at least one of information related to a selected optimal beam sweeping direction and information related to a setting of transmission parameters.
The method of claim 50, further comprising periodically performing the beam sweeping of the at least one TRS in the different spatial directions in the burst set toward the at least one second user equipment depending on at least one of a traveling speed of the user equipment and a tone spacing of a transmission carrier.
The method of claim 50, wherein the burst set of the at least one TRS comprises at least one of a full beam sweeping mode and a condense beam sweeping mode.
The method of claim 53, wherein the burst set of the at least one TRS is in the full beam sweeping mode, each beam sweeping direction is applied to an entire transmission of a transmission time interval (TTI) , and a duration of the burst set of the at least one TRS is a number of beam sweeping directions times a length of the TTI.
The method of claim 54, wherein the TTI for each beam sweeping 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) .
The method of claim 55, wherein the PSCCH carries at least a part of a source identity of the user equipment, a beam index number for the at least one TRS, a resource allocation and a size of the at least one TRS within the TTI, a power offset of beam transmissions of the at least one TRS, an absolute power of the beam transmissions of the at least one TRS, and a resource allocation of the PSSCH within the TTI.
The method of claim 56, wherein the source identity is a media access control (MAC) layer address.
The method of claim 56, 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 communicating frequency band, P_cmax is a configured maximum output power for a serving cell when in a network coverage or a pre-configured maximum output power when out of the network coverage.
The method of claim 58, wherein a zero power offset means a maximum power level allowable by a network for a TRS transmission.
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 platooning operation by the user equipment to the at least one second user equipment.
The method of claim 58, wherein a non-zero power offset means a lower power than the maximum power level.
The method of claim 53, wherein the burst set of the at least one TRS in the condense beam sweeping mode is applied to an 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 sweeping region.
The method of claim 62, wherein the SCI comprises at least a part of a source identity of the user equipment, a number of the at least one TRS within the burst set of the at least one TRS in the condense beam sweeping mode, a power offset of beam transmissions of the at least one TRS, an absolute power of the beam transmissions of the at least one TRS, a processing gap length, and a beam feedback.
The method of claim 63, wherein the source identity is a media access control (MAC) layer address.
The method of claim 63, 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 communicating frequency band, P_cmax is a configured maximum output power for a serving cell when in a network coverage or a pre-configured maximum output power when out of the network coverage.
The method of claim 65, wherein a zero power offset means a maximum power level allowable by a network for a TRS transmission.
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 platooning operation by the user equipment to the at least one second user equipment.
The method of claim 65, wherein a non-zero power offset means a lower power than the maximum power level.
The method of claim 63, wherein the number of the at least one TRS within the burst set of the at least one TRS in the condense beam sweeping mode corresponds to a number of beam sweeping directions.
The method of claim 63, wherein the SCI further indicates at least one of a gap region and a feedback region.
A method of wireless communication of a user equipment, comprising:

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

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

calculating at least one of a reference signal received power (RSRP) and a received signal strength indicator (RSSI) for the at least one TRS in a burst set of the at least one TRS; and

selecting an optimal beam sweeping direction based on at least one of an optimal RSRP result and an optimal RSSI result.
The method of claim 71, further comprising determining the optimal beam sweeping direction for transmission towards the at least one second user equipment based on at least one of an estimated time of arrival (ToA) , an angle of arrival (AoA) , and a direction of arrival (DoA) of the optimal beam sweeping direction from the at least one second user equipment.
The method of claim 72, wherein a number of the at least one second user equipment is at least two, the optimal beam sweeping direction towards one second user equipment is also the optimal beam sweeping direction for another second user equipment.
The method of claim 71, further comprising transmitting, to the at least one second user equipment, report information comprising at least one of information related to the optimal beam sweeping direction and information related to a setting of transmission parameters.
The method of claim 71, wherein the burst set of the at least one TRS comprises at least one of a full beam sweeping mode and a condense beam sweeping mode.
The method of claim 75, wherein the burst set of the at least one TRS is in the full beam sweeping mode, each beam sweeping direction is applied to an entire transmission of a transmission time interval (TTI) , and a duration of the burst set of the at least one TRS is a number of beam sweeping directions times a length of the TTI.
The method of claim 76, wherein the TTI for each beam sweeping 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) .
The method of claim 77, wherein the PSCCH carries at least a part of a source identity of the at least one second user equipment, a beam index number for the at least one TRS, a resource allocation and a size of the at least one TRS within the TTI, a power offset of beam transmissions of the at least one TRS, an absolute power of the beam transmissions of the at least one TRS, and a resource allocation of the PSSCH within the TTI.
The method of claim 78, wherein the source identity is a media access control (MAC) layer address.
The method of claim 78, 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 at least one second user equipment for a communicating frequency band, P_cmax is a configured maximum output power for a serving cell when in a network coverage or a pre-configured maximum output power when out of the network coverage.
The method of claim 80, wherein a zero power offset means a maximum power level allowable by a network for a TRS transmission.
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 platooning operation by the user equipment to the at least one second user equipment.
The method of claim 80, wherein a non-zero power offset means a lower power than the maximum power level.
The method of claim 75, wherein the burst set of the at least one TRS in the condense beam sweeping mode is applied to an 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 sweeping region.
The method of claim 84, wherein the SCI comprises at least a part of a source identity, a number of the at least one TRS within the burst set of the at least one TRS in the condense beam sweeping mode, a power offset of beam transmissions of the at least one TRS, an absolute power of the beam transmissions of the at least one TRS, a processing gap length, and a beam feedback.
The method of claim 85, wherein the source identity is a media access control (MAC) layer address.
The method of claim 86, 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 at least one second user equipment for a communicating frequency band, P_cmax is a configured maximum output power for a serving cell when in a network coverage or a pre-configured maximum output power when out of the network coverage.
The method of claim 87, wherein a zero power offset means a maximum power level allowable by a network for a TRS transmission.
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 platooning operation by the user equipment to the at least one second user equipment.
The method of claim 87, wherein a non-zero power offset means a lower power than the maximum power level.
The method of claim 85, wherein the number of the at least one TRS within the burst set of the at least one TRS in the condense beam sweeping mode corresponds to a number of beam sweeping directions.
The method of claim 85, wherein the SCI further indicates at least one of a gap region and a feedback region.
The method of claim 85, further comprising deriving a pathloss measurement for the optimal beam sweeping direction from the at least one second user equipment.
The method of claim 93, further comprising deriving the pathloss measurement according to at least one of the following equations:

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

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

where power_offset indicates a difference between Min {P_powerclass, P_cmax} and an actual TRS transmit power, P_powerclass is a power class level of the at least one second user equipment for a communicating frequency band, P_cmax is a configured maximum output power for a serving cell when in a network coverage or a pre-configured maximum output power when out of the network coverage.
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 pathloss measurement.
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 pathloss measurement.
The method of claim 96, further comprising keeping a data buffering of the user equipment at a minimal level and determining the highest MCS based on a corresponding power of the at least second user equipment, such that MCS <= Min {P_powerclass, P_cmax} .
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 pathloss measurement.
A user equipment for wireless communication, comprising:

a memory; and

a processor coupled to the memory and configured to:

perform a group communication over a sidelink interface to at least one second user equipment;

receive at least one tracking reference signal (TRS) in different spatial directions in a burst set of the at least one TRS from the at least one second user equipment; and

select an optimal beam sweeping direction, wherein the burst set of the at least one TRS is in a full beam sweeping mode, each beam sweeping direction is applied to an entire transmission of a transmission time interval (TTI) , and a duration of the burst set of the at least one TRS is a number of beam sweeping directions times a length of the TTI.
The user equipment of claim 99, wherein the TTI for each beam sweeping 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) .
The user equipment of claim 100, wherein the PSCCH carries at least a part of a source identity of the at least one second user equipment, a beam index number for the at least one TRS, a resource allocation and a size of the at least one TRS within the TTI, a power offset of beam transmissions of the at least one TRS, an absolute power of the beam transmissions of the at least one TRS, and a resource allocation of the PSSCH within the TTI.
The user equipment of claim 101, wherein the source identity is a media access control (MAC) layer address.
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, where P_powerclass is a power class level of the at least one second user equipment for a communicating frequency band, P_cmax is a configured maximum output power for a serving cell when in a network coverage or a pre-configured maximum output power when out of the network coverage.
The user equipment of claim 102, wherein the power offset of zero means a maximum power level allowable by a network for a TRS transmission.
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 platooning operation by the user equipment to the at least one second user equipment.
The user equipment of claim 102, wherein a non-zero power offset means a lower power than the maximum power level.
A user equipment for wireless communication, comprising:

a memory; and

a processor coupled to the memory and configured to:

perform a group communication over a sidelink interface to at least one second user equipment;

receive at least one tracking reference signal (TRS) in different spatial directions in a burst set of the at least one TRS from the at least one second user equipment; and

select an optimal beam sweeping direction, wherein the burst set of the at least one TRS is in a condense beam sweeping mode 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 sweeping region.
The user equipment of claim 106, wherein the SCI comprises at least a part of a source identity, a number of the at least one TRS within the burst set of the at least one TRS in the condense beam sweeping mode, a power offset of beam transmissions of the at least one TRS, an absolute power of the beam transmissions of the at least one TRS, a processing gap length, and a beam feedback.
The user equipment of claim 107, wherein the source identity is a media access control (MAC) layer address.
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, where P_powerclass is a power class level of the at least one second user equipment for a communicating frequency band, P_cmax is a configured maximum output power for a serving cell when in a network coverage or a pre-configured maximum output power when out of the network coverage.
The user equipment of claim 109, wherein a zero power offset means a maximum power level allowable by a network for a TRS transmission.
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 platooning operation by the user equipment to the at least one second user equipment.
The user equipment of claim 109, wherein a non-zero power offset means a lower power than the maximum power level.
The user equipment of claim 107, wherein the number of the at least one TRS within the burst set of the at least one TRS in the condense beam sweeping mode corresponds to a number of beam sweeping directions.
The user equipment of claim 107, wherein the SCI further indicates at least one of a gap region and a feedback region.