CN111480302B

CN111480302B - User equipment and wireless communication method thereof

Info

Publication number: CN111480302B
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: 2023-05-16
Anticipated expiration: 2038-02-02
Also published as: CN116436504A; CN111480302A; 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 device over a side-downlink interface, and to periodically perform beam scanning of at least one Tracking Reference Signal (TRS) towards the at least one second user device in different spatial directions in a burst set of the TRS.

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 user equipment and wireless communication methods thereof.

2. Description of related Art

For future fifth generation new wireless (5G-NR) mobile communication systems, it has been decided that 5G-NR system mobile communication can support wireless transmission and reception in ultra-high frequency (SHF) spectrum and even extremely-high frequency (EHF) spectrum, such as millimeter wave (mmW) band, which is advantageous for directional transceiver operation, such as beamforming and multiple-input multiple-output (MIMO). This is combined with the trend to employ more antenna elements in user equipment such as mobile phones and wireless devices in vehicles, the recent design of 5G-NR for Downlink (DL) and Uplink (UL) operation incorporates 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-side uplink techniques for direct user equipment to user equipment (UE-to-UE) discovery and communication via a PC5 interface without routing through a BS, it is contemplated that MIMO and/or beamforming-like operations may also be supported to enhance system operation and support more advanced use cases. However, in current Long Term Evolution (LTE) side-chain technology for device-to-device (D2D) communications and vehicle-to-everything (V2X) communications including vehicle-to-vehicle (V2V), vehicle-to-pedestrian (V2P), and vehicle-to-infrastructure/network (V2I/N), MIMO and beamforming like operations are not supported. Thus, the side-uplink signals and channels are transmitted omnidirectionally from each UE. In addition, the UE transmits at maximum allowed power regardless of channel type (e.g., control channel or data channel), signal type (e.g., synchronization signal or reference signal), operating conditions (e.g., intra-network coverage or out-of-network coverage), and communication type (e.g., broadcast, multicast, or unicast) to achieve maximum signal coverage and communication range. For both unicast and multicast type communications, it is a fairly power-inefficient way to use the UE's battery power when the required communication range is much smaller than the signal coverage from transmitting at the maximum allowed power. For example, when UEs communicating in a group are very close, e.g., 10 meters, or are directly adjacent to each other, the relative speed between the UEs is low, or the transmission rate/Modulation and Coding Scheme (MCS) level is low. Furthermore, signaling transmitted at a power level greater than the desired power level may also increase interference to signaling from other UEs outside the desired communication group and thus limit the amount of available resources that other UEs can utilize.

Disclosure of Invention

An object of the present disclosure is to propose a User Equipment (UE) and a wireless communication method thereof, which are capable of performing a beamforming operation and setting transmission related parameters for side-uplink 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 at least one second user equipment over a side-downlink 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 (burst set) of the at least one TRS.

According to an embodiment in combination with the first aspect of the present 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 related to the selected best beam scanning direction and information related to the setting of the transmission parameters.

According to an embodiment in combination with the first aspect of the present 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 travel speed of the user equipment and a frequency interval (tone spacing) of the transmission carrier.

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

According to an embodiment in combination with the first 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 for an entire transmission of a Transmission Time Interval (TTI), and the duration of the burst set of at least one TRS is the number of beam scanning directions times the length of the TTI.

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

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 at least one TRS, a resource allocation and size of at least one TRS within a TTI, a power offset of a beam transmission of at least one TRS, an absolute power of a beam transmission of at least one TRS and a resource allocation of the PSSCH within a TTI.

According to an embodiment in combination with the first aspect of the present disclosure, the source identity 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, wherein 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 outside network coverage.

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

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

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

According to an embodiment in combination with the first aspect of the present disclosure, the burst set of at least one TRS in compressed beam scanning mode is applied for the entire transmission of the TTI and comprises a Guard Period (GP)/Automatic Gain Control (AGC) region, a PSCCH carrying side-uplink 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 present disclosure, the SCI comprises at least a portion of a source identity of the user equipment, 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 the 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 present 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 an embodiment in combination with 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 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 side-uplink interface, 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 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 an optimal RSRP result and an optimal RSSI result.

According to a further embodiment in combination with the second aspect of the present disclosure, 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), an angle of arrival (AoA) and a direction of arrival (DoA) of the optimal beam scanning direction from the at least one second user equipment.

According to a further embodiment in combination with the second aspect of the present disclosure, the number of at least one second user equipment is at least two, the optimal beam scanning direction towards one second user equipment being also the optimal beam scanning direction towards the other second user equipment.

According to a further embodiment in combination with the second aspect of the present disclosure, 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 the setting of the transmission parameters.

According to another embodiment in combination with the second 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 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 for an entire transmission of a Transmission Time Interval (TTI), and the duration of the burst set of at least one TRS is the number of beam scanning directions times the length of the TTI.

According to another embodiment in combination with 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 uplink control channel (PSCCH), a training RS, and a physical side uplink shared channel (PSSCH).

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

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

According to another embodiment in combination with the second aspect of the present 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 of at least one second 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 outside network coverage.

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

According to another embodiment in combination with the second aspect of the present disclosure, the maximum power level is configured to be used during an initial group communication over the side-uplink 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 second aspect of the present disclosure, the non-zero power offset means a power lower than the maximum power level.

According to another embodiment in combination with the second aspect of the present disclosure, the burst set of at least one TRS in compressed beam scanning mode is applied for the entire transmission of the TTI and comprises a Guard Period (GP)/Automatic Gain Control (AGC) region, a PSCCH carrying side-uplink 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 present disclosure, the SCI includes at least a portion of a source identity, 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.

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

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

According to a further embodiment in combination with the second aspect of the present disclosure, the processor is further configured to derive the path loss 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 the difference between Min { p_powerclass, p_cmax } which is the power level of at least one second user equipment for the communication band, and the actual TRS transmit power, p_powerclass is the maximum output power configured for the serving cell when in network coverage or the maximum output power preconfigured when outside network coverage.

According to another embodiment in combination with 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 path loss measurement.

According to another embodiment in combination with the second aspect of the present disclosure, the processor is further configured to determine an MCS level for a 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 present disclosure, the processor is further configured to keep the data buffering of the user equipment at a minimum level and to determine the highest MCS based on the respective power of the at least one second user equipment such that MCS < = Min { p_powerclass, p_cmax }.

According to a further embodiment in combination with 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 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 through a side uplink interface, and periodically performing 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 the TRS.

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 best 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 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 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 present 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 the duration of the burst set of at least one TRS is the number of beam scanning directions times the length of the TTI.

According to another embodiment in combination with 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 uplink control channel (PSCCH), a training RS, and a physical side uplink shared channel (PSSCH).

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

According to another embodiment in combination with the third aspect of the present 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 the power class level of the user equipment for the communication band and p_cmax is the maximum output power configured for the serving cell when in network coverage or the maximum output power preconfigured when outside network coverage.

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

According to another embodiment in combination with the third aspect of the present disclosure, the maximum power level is configured to be used during an initial group communication over the side-uplink 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 present disclosure, the non-zero power offset means a power lower than the maximum power level.

According to another embodiment in combination with the third aspect of the present disclosure, the burst set of at least one TRS in compressed beam scanning mode is applied for the entire transmission of the TTI and comprises a Guard Period (GP)/Automatic Gain Control (AGC) region, a PSCCH carrying side-uplink 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 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 present disclosure, the power offset indicates a difference between Min { p_powerclass, p_cmax } and the actual TRS transmit power, where p_powerclass is the power class level of the user equipment for the communication band and p_cmax is the maximum output power configured for the serving cell when in network coverage or preconfigured when outside network coverage.

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

According to a further embodiment in combination with 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 wireless communication method of a user equipment includes: performing group communication to at least one second user equipment through a side-uplink interface, 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 Indication (RSSI) for the at least one TRS in the burst set of the at least one TRS, and selecting 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 fourth aspect of the present disclosure, the method further comprises 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), an angle of arrival (AoA) and a direction of arrival (DoA) of the optimal beam scanning direction from the at least one second user equipment.

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

According to a further embodiment in combination with the fourth aspect of the present disclosure, the method further comprises 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 the setting of the transmission parameters.

According to another embodiment in combination with the fourth 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 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 for an entire transmission of a Transmission Time Interval (TTI), and the duration of the burst set of at least one TRS is the number of beam scanning directions times the length of the TTI.

According to another embodiment in combination with 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 uplink control channel (PSCCH), a training RS, and a physical side uplink shared channel (PSSCH).

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 at least one second user equipment, a beam index number for at least one TRS, a resource allocation and size of at least one TRS within a TTI, a power offset of a beam transmission of at least one TRS, an absolute power of a beam transmission of at least one TRS and a resource allocation of a PSSCH within a TTI.

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

According to another embodiment in combination with the fourth aspect of the present 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 of at least one second 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 outside network coverage.

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

According to another embodiment in combination with the fourth aspect of the present disclosure, the maximum power level is configured to be used during an initial group communication over the side-uplink 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 fourth aspect of the present disclosure, the non-zero power offset means a power lower than the maximum power level.

According to another embodiment in combination with the fourth aspect of the present disclosure, the burst set of at least one TRS in compressed beam scanning mode is applied for the entire transmission of the TTI and comprises a Guard Period (GP)/Automatic Gain Control (AGC) region, a PSCCH carrying side-uplink 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 present disclosure, the SCI includes at least a portion of a source identity, 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.

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

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

According to another embodiment in combination with the fourth aspect of the present disclosure, the method further comprises deriving the path loss 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 combination with the fourth aspect of the present 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 present disclosure, the method further comprises determining an MCS level for a 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 fourth aspect of the present disclosure, the method further comprises maintaining the data buffering of the user equipment at a minimum level and determining the highest MCS based on the respective power of the at least one second user equipment such that MCS < = Min { p_powerclass, p_cmax }.

According to another embodiment in combination with the fourth aspect of the present 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 present 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 device over a side-uplink interface, receive at least one Tracking Reference Signal (TRS) in different spatial directions among a burst of the at least one TRS from the at least one second user device, and select a best beam scanning direction, wherein the burst of the 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 of the at least one TRS is a number of beam scanning directions times a length of the TTI.

According to another embodiment in combination with 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 uplink control channel (PSCCH), a training RS, and a physical side uplink shared channel (PSSCH).

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

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

According to another embodiment in combination with the fifth aspect of the present 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 of at least one second 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 outside network coverage.

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

According to another embodiment in combination with the fifth aspect of the present disclosure, the maximum power level is configured to be used during an initial group communication over the side-uplink 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 fifth aspect of the present disclosure, the non-zero power offset means a power lower 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 group communication to at least one second user device over a side-link interface, 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 device, and select a best beam scanning direction, wherein the burst set of the at least one TRS is in a compressed beam scanning mode and includes a Guard Period (GP)/Automatic Gain Control (AGC) region, a PSCCH carrying side-link control information (SCI) for scheduling the at least one TRS, and a TRS beam scanning region.

According to another embodiment in combination with the sixth aspect of the present disclosure, the SCI includes at least a portion of a source identity, 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.

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

According to another embodiment in combination with the sixth aspect of the present 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 of at least one second 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 outside network coverage.

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

According to another embodiment in combination with the sixth aspect of the present disclosure, the maximum power level is configured to be used during an initial group communication over the side-uplink 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 sixth aspect of the present disclosure, the non-zero power offset means a power lower than the maximum power level.

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

According to a further embodiment in combination with 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 disclosure, the user equipment and the wireless communication method thereof can perform beamforming operation and set transmission related parameters for side uplink communication in a group environment, so that the user equipment can save batteries, perform long-time operation and/or have good operation performance due to less interference.

Drawings

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

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 wireless communication method according to the present disclosure from an operational aspect of a user equipment for transmitting signals.

Fig. 3 is a flow chart illustrating a wireless communication method according to the present disclosure from an operational aspect of a user equipment for receiving signals.

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

Fig. 5 is a diagram of burst sets of at least one TRS in a full beam scanning 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 participate in a side-uplink 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 attached drawings, by way of technical subject matter, structural features, achieved objects, and effects. In particular, the terminology in the embodiments of the disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of 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 group communication to the at least one user equipment 200 over a side-uplink 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 at least one TRS, such that the at least one user equipment 100 may save battery, operate for long periods of time, and/or have good performance due to less interference. At least one user equipment 100 may be a user equipment for transmitting signals and at least one user equipment 200 may be a user equipment for receiving signals. In some embodiments, group communication between at least one user device 100 and at least one user device 200 over a side-link interface, such as a PC5 interface, may be based on LTE side-link technology and/or fifth generation new wireless (5G-NR) radio access technology developed under the third generation partnership project (3 GPP) of release 14.

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 the at least one user equipment 100 over a side-link interface, such as a PC5 interface, 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 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 an optimal RSRP result and an optimal RSSI result such that the at least one user equipment 100 may save battery, operate for long periods of time, and/or have good operational performance due to less interference.

In some embodiments, the processor 204 is further configured to determine the 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), an angle of arrival (AoA), and a direction of arrival (DoA) from the at least one user equipment 100. The number of at least one user equipment 100 is at least two, the optimal beam scanning direction towards one user equipment 100 being also the optimal beam scanning direction towards 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 scanning direction from the at least one user equipment 100. The processor 204 is further configured to derive the path loss 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 the difference between Min { p_powerclass, p_cmax } which is the power class level of at least one user equipment 100 for the communication band, and the actual TRS transmit power, p_powerclass is the maximum output power configured for the serving cell when in network coverage or the maximum output power pre-configured when outside 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 the respective power of the at least one 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 include Application Specific Integrated Circuits (ASICs), other chipsets, logic circuits, and/or data processing devices. The

processors

104 and 204 may each 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 device 100 and the at least one user device 200 involves vehicle-to-everything (V2X) communication according to LTE-side uplink technology and/or 5G-NR radio access technology developed under release 14's 3GPP, 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 according to the present disclosure in terms of operation of a user device 100 for transmitting signals. The method 300 includes: group communication is performed to the at least one user equipment 200 over a side-uplink 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 the at least one TRS, at block 304, such that the at least one user equipment 100 may save battery, operate for long periods of time, and/or have good performance due to less interference.

Fig. 3 illustrates a wireless communication method 400 according to the present disclosure in terms of operation of a user device 200 for receiving signals. The method 400 includes: at block 402, group communication is performed to at least one user equipment 100 over a side-uplink interface, such as a PC5 interface, at block 404, at least one Tracking Reference Signal (TRS) in different spatial directions in a burst set of the at least one TRS is received from the at least one user equipment 100, 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 is calculated at block 406, and at block 408, an optimal beam scan direction is selected based on at least one of an optimal RSRP result and an optimal RSSI result such that the at least one user equipment 100 may save battery, operate for a long time, and/or have good operational performance due to less interference.

Fig. 1 and 4-6 illustrate 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 including at least one of information related to the selected optimal beam scanning direction and information related 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 the 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 the 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 scanning pattern as shown in fig. 5 and a compressed beam scanning pattern as shown in fig. 6.

Fig. 1 and 5 illustrate that in some embodiments, the burst set of at least one TRS is in a full beam scanning mode. Each beam scanning direction is applied to the entire transmission of a Transmission Time Interval (TTI). The duration of the burst 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 uplink control channel (PSCCH), a training RS, and a physical side uplink shared channel (PSSCH). The PSCCH carries at least a portion of a source identification of the user equipment 100, a beam index number for at least one TRS, a resource allocation and size of at least one TRS within a TTI, a power offset of a beam transmission of at least one TRS, an absolute power of a beam transmission of at least one TRS, and a resource allocation of a PSSCH within a TTI. The training RS may occupy one or more Orthogonal Frequency Division Multiplexing (OFDM) symbols. The PSSCH may carry an information data Transport Block (TB). The source identification is a Media Access Control (MAC) layer address or a member number within the sidelink communication group that uniquely identifies the user device 100.

Fig. 1 and 5 further illustrate that in some embodiments, the power offset indicates the difference between Min { p_powerclass, p_cmax } and the actual TRS transmit power, where p_powerclass is the power class level of the user equipment for the communication band and p_cmax is the maximum output power configured for the serving cell when in network coverage or the pre-configured maximum output power when outside network coverage. The zero power offset means the maximum power level allowed by the network for TRS transmission. The maximum power level is configured to be used during initial group communication over the side-uplink interface or in a queuing operation of the user device 100 to at least one user device 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 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 illustrate that in some embodiments, the burst set of at least one TRS is in a compressed beam scanning mode. The burst set of at least one TRS in compressed beam scanning mode is applied to the entire transmission of the TTI and includes a Guard Period (GP)/Automatic Gain Control (AGC) region, a PSCCH carrying side-link 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 identity 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 side-uplink communication group that uniquely identifies the user device 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 measurements and selection of the best beam. The size of the beam feedback reporting area may allocate resources to 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 may be as short as one OFDM symbol. If a gap region is indicated in the SCI, the user equipment 200 can calculate RSRP/RSSI measurements of the TRS for each transmission with the gap duration in the gap region 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 a 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 the difference between Min { p_powerclass, p_cmax } and the actual TRS transmit power, where p_powerclass is the power class level of the user equipment for the communication band and p_cmax is the maximum output power configured for the serving cell when in network coverage or the pre-configured maximum output power when outside network coverage. The zero power offset means the maximum power level allowed by the network for TRS transmission. The maximum power level is configured to be used during initial group communication over the side-uplink interface or in queuing operations of the user device 100 to at least one user device 200 to reach as many user 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 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. 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 an RSRP or RSSI for the TRSs of each transmission within the burst set and selects the best beam based on the best RSRP/RSSI result, e.g., the highest RSRP/RSSI result. As in the example of 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 transmissions towards each transmitting UE based on the estimated ToA, aoA, and/or DoA of the selected best beam from each transmitting UE. Sometimes the appropriate beam direction towards one UE may also be the best appropriate beam direction for another UE. As in the example of fig. 7, UE3 determines beam 1 as the best suitable direction for transmissions towards UE4 and UE6, beam 2 as the best suitable direction for transmissions towards UE1 and UE5, and beam 3 as the best suitable direction for transmissions towards UE 2.

In some embodiments, the receiving UE derives the PathLoss measurement from the RSRP/RSSI result of each selected best beam and the corresponding power_offset indicated in SCI according to PathLoss (PL) =min { p_powerclass, p_cmax } -power_offset-RSRP/RSSI. As in the example of fig. 7, UE3 derives the path loss for the selected best beam from each UE. The path loss assumption for the selected best beam from each UE is: pl=6 dB for beam 3 from UE1, pl=3 dB for beam 4 from UE2, pl=3 dB for beam 1 from UE4, pl=4 dB for beam 2 from UE5, and pl=8 dB for beam 3 from UE 6.

In some embodiments, in the calculated PL of the best beam selected for each transmitting 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 PL link so that the common MCS is used for the next multicast transmission and may decode all members of the group. Meanwhile, the Rx UE may also consider its own data buffer status in order to keep the data buffer at a minimum level. The highest MCS level that can be selected/supported should be based on its corresponding desired rx_power, so that the desired rx_power (MCS) <=min { p_power class, p_cmax }. As in the example of fig. 7, UE3 will select the MCS level corresponding to the 8dB PL link from UE 6.

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 according to p_tx (beam x) =required tx_power (MCS) +pl (selected best beam). As in the example of fig. 7, assuming that the highest MCS level for the 8dB PL link from UE6 would require an Rx power level of 10dBm, 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=16 dBm, and

p_tx (beam 3 towards UE 2) =10dbm+3db=13 dBm.

In the embodiment of the disclosure, the user equipment and the wireless communication method thereof can execute the beam forming operation and set the transmission related parameters for the side uplink communication in the group environment, so that the user equipment can save batteries, perform long-time operation and/or have good running performance due to less interference.

Those of ordinary skill in the art will appreciate that each of the units, algorithms, and steps described and disclosed in the embodiments of the disclosure are implemented using electronic hardware, or a combination of software and electronic hardware for a computer. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the particular application. Those of ordinary skill in the art will be able to implement the functionality for each particular application in a different manner without departing from the scope of the present disclosure.

One of ordinary skill in the art will appreciate that he/she can refer to the operation of the systems, devices and units in the above-described embodiments because the operation of the systems, devices and units described above 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-described embodiments are merely exemplary. The partitioning of the cells is based solely on logic functions, while other partitions exist in the implementation. 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, through some port, device or unit, in electrical, mechanical or other form.

The units that are separate components for explanation are physically separate or not. The units used for display may or may not be physical units, i.e. located in one place or distributed over a plurality of network units. 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, be physically separate, or be 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 substantially or partly in the form of a software product. Alternatively, a part of the technical solution beneficial to the conventional technology can be implemented in the form of a software product. The software product in the 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 present 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 present disclosure is not limited to the disclosed embodiment, but is intended to cover various arrangements made without departing from the scope of the appended claims in its broadest interpretation.

Claims

1. A user equipment for wireless communication, comprising:

a memory; and

a processor coupled to the memory and configured to:

performing group communication to at least one second user equipment through a side uplink interface; and

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

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 including at least one of information related to the selected best beam scanning direction and information related to a setting of transmission parameters.

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

4. The user equipment of claim 1, wherein the burst set of the at least one TRS comprises at least one of a full beam scanning mode and a compressed beam scanning mode.

5. The user equipment of claim 4, wherein the burst of the at least one TRS is 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 burst of the at least one TRS is a number of beam scanning directions multiplied by a length of the TTI.

6. The user equipment of claim 5, wherein the TTI for each beam scanning direction includes a guard period GP/automatic gain control, AGC, region, physical side uplink control channel, PSCCH, training RS, and physical side uplink 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 medium 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 actual TRS transmit power, wherein p_powerclass is a power class level of the user equipment for a communication band, p_cmax is a maximum output power configured for a serving cell when in network coverage or a maximum output power preconfigured when outside 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 to be used during an initial group communication over the side-uplink interface or in a queuing operation of the user equipment to the at least one second user equipment.

12. The user equipment of claim 10, wherein a non-zero power offset means a lower power 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 side-link 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 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 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 medium 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 actual TRS transmit power, wherein p_powerclass is a power class level of the user equipment for a communication band, p_cmax is a maximum output power configured for a serving cell when in network coverage or a pre-configured maximum output power when outside 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 to be used during an initial group communication over the side-uplink interface or in a queuing operation of the user equipment to the at least one second user equipment.

19. The user equipment of claim 17, wherein a non-zero power offset means a lower power than the maximum power level.

20. 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 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 group communication to at least one second user equipment through a side uplink 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 the at least one TRS;

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 the at least one TRS; and

the best beam scanning direction is selected based on at least one of the best RSRP result and the best 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 number of the at least one second user equipment is at least two, the optimal beam scanning direction towards one second user equipment being the optimal beam scanning direction towards 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 including at least one of information related to the optimal beam scanning direction and information related to a setting of transmission parameters.

26. The user equipment of claim 22, wherein the burst set of the at least one TRS comprises at least one of a full beam scanning mode and a compressed beam scanning mode.

27. The user equipment of claim 26, wherein the burst of the at least one TRS is 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 burst 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, region, physical side uplink control channel, PSCCH, training RS, and physical side uplink shared channel, PSSCH.

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 PSSCH within the TTI.

30. The user equipment of claim 29, wherein the source identification is a medium 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 actual TRS transmit power, wherein p_powerclass is a power class level of the at least one second user equipment for a communication band, p_cmax is a maximum output power configured for a serving cell when in network coverage or a maximum output power preconfigured when outside 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 to be used during an initial group communication over the side-uplink interface or in a queuing operation of the user equipment to the at least one second user equipment.

34. The user equipment of claim 32, wherein a non-zero power offset means a lower power 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 comprises a guard period GP/automatic gain control AGC region, a PSCCH carrying side-link 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 identity, 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 medium 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 actual TRS transmit power, wherein p_powerclass is a power class level of the at least one second user equipment for a communication band, p_cmax is a maximum output power configured for a serving cell when in network coverage or a maximum output power preconfigured when outside 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 to be used during an initial group communication over the side-uplink interface or in a queuing operation of the user equipment to the at least one second user equipment.

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

42. 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 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 scanning 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 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 the difference between Min { p_powerclass, p_cmax } which is the power class level of the at least one second user equipment for the communication band, and the actual TRS transmit power, p_powerclass is the maximum output power configured for the serving cell when in network coverage or the maximum output power pre-configured 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 pathloss measurement.

48. The user equipment of claim 47, wherein the processor is further configured to keep data buffering of the user equipment at a minimum level and to determine a highest MCS based on the respective power of the at least one 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 for a user device, comprising:

Beam scanning of at least one tracking reference signal TRS is performed periodically towards the at least one second user equipment in different spatial directions in the burst.

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

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

53. The method of claim 50, wherein the burst set of the at least one TRS comprises at least one of a full beam scanning mode and a compressed beam scanning mode.

54. The method of claim 53, wherein the burst of the at least one TRS is 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 burst of the at least one TRS is a number of beam scanning 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-uplink control channel, PSCCH, a training RS, and a physical side-uplink 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 medium 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 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 pre-configured maximum output power when outside of the network coverage.

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

60. The method of claim 59, wherein the maximum power level is configured for use during initial group communication over the side-uplink interface or in queuing operations of the user equipment to the at least one second user equipment.

61. The method of claim 59, wherein a non-zero power offset means 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 side-uplink control information SCI 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 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 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 medium 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 actual TRS transmit power, wherein p_powerclass is a power class level of the user equipment for a communication band, p_cmax is a maximum output power configured for a serving cell when in network coverage or a pre-configured maximum output power 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 to be used during initial group communication over the side-uplink interface or in a queuing operation of the user equipment to the at least one second user equipment.

68. The method of claim 66 wherein a non-zero power offset means 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 burst set 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 for a user device, comprising:

72. The method of claim 71, further comprising determining the optimal beam scanning direction for transmissions towards the at least one second user device 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 device.

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

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

75. The method of claim 71, wherein the burst set of the at least one TRS comprises at least one of a full beam scanning mode and a compressed beam scanning mode.

76. The method of claim 75, wherein the burst of the at least one TRS is 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 burst of the at least one TRS is a number of beam scanning 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, physical side uplink control channel, PSCCH, training RS, and physical side uplink 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 medium 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 actual TRS transmit power, wherein p_powerclass is a power class level of the at least one second user device for a communication band, p_cmax is a maximum output power configured for a serving cell when in network coverage or a maximum output power pre-configured 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 to be used during initial group communication over the side-uplink interface or in a queuing operation of the user equipment to the at least one second user equipment.

83. The method of claim 81, wherein a non-zero power offset means a lower power 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 side-uplink control information SCI for scheduling the at least one TRS, and a TRS beam scanning region.

85. The method of claim 84 wherein the SCI includes 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.

86. The method of claim 85, wherein the source identification is a medium 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 actual TRS transmit power, wherein p_powerclass is a power class level of the at least one second user device for a communication band, p_cmax is a maximum output power configured for a serving cell when in network coverage or a maximum output power pre-configured 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 to be used during initial group communication over the side-uplink interface or in a queuing operation of the user equipment to the at least one second user equipment.

90. The method of claim 88, wherein a non-zero power offset means 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 burst set 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 scanning 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:

PathLoss (PL) =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 measurement.

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 data buffering of the user equipment at a minimum level and determining a highest MCS based on the respective power of the at least one second user equipment such that MCS < = Min { p_powerclass, 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 at least one tracking reference signal TRS from the at least one second user equipment in different spatial directions in a burst set of the at least one TRS; and

the method further comprises selecting an optimal beam scanning direction, wherein the burst set of the 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 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, physical side uplink control channel, PSCCH, training RS, and physical side uplink shared channel, PSSCH.

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 PSSCH within the TTI.

102. The user equipment of claim 101, wherein the source identity is a medium access control, MAC, layer address.

103. The user equipment of claim 102, wherein the power offset indicates a difference between Min { p_powerclass, p_cmax } and actual TRS transmit power, wherein p_powerclass is a power class level of the at least one second user equipment for a communication band, 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 103, wherein a zero power offset implies a maximum power level allowed by the network for TRS transmissions.

105. The user equipment of claim 104, wherein the maximum power level is configured to be used during initial group communication over the side-uplink interface or in a queuing operation of the user equipment to the at least one second user equipment.

106. The user equipment of claim 104, wherein a non-zero power offset means 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:

the optimal beam scanning direction is selected, 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 region, a PSCCH carrying side-link control information SCI for scheduling the at least one TRS, and a TRS beam scanning region.

108. The user equipment of claim 107, wherein the SCI comprises at least a portion of a source identity, 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 108, wherein the source identity is a medium access control, MAC, layer address.

110. The user equipment of claim 109, wherein the power offset indicates a difference between Min { p_powerclass, p_cmax } and actual TRS transmit power, wherein p_powerclass is a power class level of the at least one second user equipment for a communication band, 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 110, wherein a zero power offset implies a maximum power level allowed by the network for TRS transmissions.

112. The user equipment of claim 111, wherein the maximum power level is configured to be used during initial group communication over the side-uplink interface or in a queuing operation of the user equipment to the at least one second user equipment.

113. The user equipment of claim 111, wherein a non-zero power offset means a lower power than the maximum power level.

114. The user equipment of claim 108, wherein the number of the at least one TRS within the burst set 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 108, wherein the SCI further indicates at least one of a gap region and a feedback region.

116. A computer readable storage medium storing computer readable instructions which, when executed by a processor, cause the processor to perform the method of any one of claims 50 to 70.

117. A computer readable storage medium storing computer readable instructions which, when executed by a processor, cause the processor to perform the method of any one of claims 71 to 98.