Patent Description:
In current long term evolution (LTE) sidelink (SL) device-to-device (D2D) and vehicle-to-everything (V2X) communications, transmitting user equipment (UE) often uses maximum allowable output power for transmitting SL signals and channels in order to reach as large as possible wireless coverage areas to support mission critical services and road safety applications and at the same time to ensure that high reliability of wireless SL communication connections are maintained for a given required distance range. Moreover, for these types of applications and services, higher UE power class is additionally defined in 3rd generation partnership project (3GPP) with an expectation that UEs are required to transmit at even higher output power levels.

While traditionally this working principal of always using the maximum available output power may hold true for target use cases and services, but it imposes significant amount of load on UE battery consumption especially for portable devices such as tablets, smartphones, augmented reality / virtual reality (AR/VR) glasses, laptops, and etc., when wireless SL communication technologies are used for commercial services. Even for mission critical applications and V2X services, often there are UEs deployed in the field with limited power supply such as portable communication devices carried by emergency personnel and pedestrian UEs. For some advanced V2X use cases, furthermore, large wireless SL signal coverage may not be as critical when a target V2X communication range is only between cars that are close to each other, such as autonomous driving and sensor sharing. If UE's output power for SL transmissions can be reduced, not only UE battery power can be saved, but also the interferences that it would cause to surrounding UEs can be limited and thus improving overall system performance.

Therefore, there is a need for an apparatus and a method for transmission power control of the same, which can provide a good communication performance and high reliability.

The document, <NPL>") discusses various aspects of sidelink physical layer procedures, including HARQ procedure, sidelink CSI, multi-antenna based transmission and sidelink power control. In the aspect of sidelink power control, one method for calculating the path loss of sidelink is that the UE-A transmits one sidelink reference signal to the UE-B, the UE-B measures the RSRP of that sidelink reference signal and then feedbacks the RSRP to the UE-A, and the UE-A calculates the path loss by path loss = Tx power of sidelink reference signal - reported RSRP.

<CIT> (<NUM>-<NUM>-<NUM>) discloses a method by which a first device performs wireless communication, and a device for supporting same. The method can comprise the steps of: transmitting one or more reference signals (RSs) to a second device on the basis of first transmit power; receiving, from the second device, information related to a channel state measured on the basis of the one or more RSs; changing the first transmit power to second transmit power on the basis of the information related to the channel state; and transmitting the one or more RSs to the second device on the basis of the second transmit power.

<CIT> (<NUM>-<NUM>-<NUM>) discloses a power control method and a power control apparatus. The method includes: sending, by a first terminal device, a first signal to a second terminal device at a first transmit power; receiving, by the first terminal device, first information from the second terminal device, where the first information is used to indicate or includes a first received power, and the first received power is a received power of the first signal; determining, by the first terminal device, an estimated value of a path loss between the first terminal device and the second terminal device based on the first transmit power and the first received power.

<CIT> (<NUM>-<NUM>-<NUM>) discloses a method of measuring and reporting radio resources by a mobile terminal operating while retuning to a plurality of subbands in a wireless communication system, comprising receiving measurement configuration including one or more subbands for measuring a reference signal received power from a specific cell and measuring a reference signal received power in an operating subband of the mobile terminal when the operating subband of the mobile terminal matches the measurement configuration.

The document, <NPL>") discusses several aspects of sidelink resource allocation for NR V2X based on the contributions of RAN#<NUM> meeting and RAN2#<NUM>, #<NUM> meeting, and provides some observations and proposals.

The document, <NPL>") discusses some issues for RRM procedure based on the contributions in RAN2#<NUM> and #<NUM>, and provides some observations and proposals.

The document, <NPL>") discusses some issues on procedures for feedback based HARQ retransmissions, CSI acquisition, power control, etc., and provides some observations and proposals.

The document, <NPL>") discusses some issues on UE procedures for sidelink, which mainly include synchronization procedures, power control, UE procedure for reporting HARQ-ACK on sidelink, UE procedure for transmitting PSCCH, UE procedure for reporting HARQ-ACK, and UE procedure for LTE sidelink transmission.

An object of the present disclosure is to propose an apparatus and a method for transmission power control of the same, as defined in the appended claims, which can provide a good communication performance and high reliability.

The present disclosure discloses, in a first aspect of the present disclosure, a first user equipment for transmission power control including a memory, a transceiver, and a processor coupled to the memory and the transceiver. The processor is configured to control the transceiver to send a trigger signaling to a second UE to request the second UE to report a sidelink - reference signal received power (SL-RSRP) measurement result, control the transceiver to receive, from the second UE, the SL-RSRP measurement report, and estimate a pathloss between the first UE and the second UE according to the reported SL-RSRP measurement result. The transceiver is further configured to receive, from the second UE, the SL-RSRP measurement report via physical sidelink shared channel, PSSCH; wherein the trigger signaling indicates a SL-RSRP measurement reporting interval; the trigger signaling for the SL-RSRP measurement reporting is part of a radio resource control, RRC, signaling; the pathloss between the first UE and the second UE is estimated according to a reference SL transmission power level used for transmitting the PSSCH from the first UE to the second UE.

The present disclosure discloses, in a second aspect of the present disclosure, a method for transmission power control of a first user equipment including: sending a trigger signaling to a second UE to request the second UE to report a sidelink - reference signal received power (SL-RSRP) measurement result, receiving, from the second UE, the SL-RSRP measurement report, and estimating a pathloss between the first UE and the second UE according to the reported SL-RSRP measurement result. The receiving, from the second UE, the SL-RSRP measurement report (<NUM>) comprises: receiving, from the second UE, the SL-RSRP measurement report via physical sidelink shared channel, PSSCH; wherein the trigger signaling indicates a SL-RSRP measurement reporting interval; the trigger signaling for the SL-RSRP measurement reporting is part of a radio resource control, RRC, signaling; the pathloss between the first UE and the second UE is estimated according to a reference SL transmission power level used for transmitting the PSSCH from the first UE to the second UE.

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.

In some embodiments of the present disclosure, receiver user equipment (UE) measurement and feedback to control transmitter UE's output power for sidelink (SL) data transmissions is provided to solve the above described issues of UE battery power consumption and generating unnecessary interferences to surrounding UEs. Benefits from adopting the proposed method of power control for wireless SL transmissions of some embodiments include:.

<FIG> illustrates that, in some embodiments, a first user equipment (UE) <NUM> and a second user equipment <NUM> for transmission power control in a communication network system <NUM> according to an embodiment of the present disclosure are provided. The communication network system <NUM> includes the first UE <NUM> and the second UE <NUM>. The first UE <NUM> may include a memory <NUM>, a transceiver <NUM>, and a processor <NUM> coupled to the memory <NUM>, the transceiver <NUM>. The second UE <NUM> may include a memory <NUM>, a transceiver <NUM>, and a processor <NUM> coupled to the memory <NUM>, the transceiver <NUM>. The processor <NUM> or <NUM> may be configured to implement proposed functions, procedures and/or methods described in this description. Layers of radio interface protocol may be implemented in the processor <NUM> or <NUM>. The memory <NUM> or <NUM> is operatively coupled with the processor <NUM> or <NUM> and stores a variety of information to operate the processor <NUM> or <NUM>. The transceiver <NUM> or <NUM> is operatively coupled with the processor <NUM> or <NUM>, and transmits and/or receives a radio signal.

The communication between UEs 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 a sidelink technology developed under 3rd generation partnership project (3GPP) long term evolution (LTE) and new radio (NR) Release <NUM> and beyond. UEs are communicated with each other directly via a sidelink interface such as a PC5 interface. Some embodiments of the present disclosure relate to sidelink communication technology in 3GPP NR release <NUM> and beyond.

In some embodiments, the processor <NUM> is configured to control the transceiver <NUM> to send a trigger signaling to the second UE <NUM> to request the second UE <NUM> to report a sidelink - reference signal received power (SL-RSRP) measurement result, control the transceiver <NUM> to receive, from the second UE <NUM>, the SL-RSRP measurement report, and estimate a pathloss between the first UE <NUM> and the second UE <NUM> according to the reported SL-RSRP measurement result. Benefits from adopting the proposed method of power control for wireless SL transmissions of some embodiments include: <NUM>. Saving portable UE device's battery power, and this will lead to longer device operating time. Minimizing interference to other surrounding nearby UEs, resulting in better SL system performance and more radio frequency reuse in more areas. Minimizing interference to cellular uplink (UL) base station (BS) receiver and better cellular performance in a UL direction. Better adaptation of SL transmission parameters to wireless channel environment, and this will lead to more reliable SL data transfer, better radio resource utilization, improved data throughput, and possibly shorter data transfer latency.

The trigger signaling indicates a SL-RSRP measurement reporting interval. The trigger signaling for the SL-RSRP measurement reporting is part of a radio resource control (RRC) signaling. In another embodiment which is not part of the claimed invention, the trigger signaling further indicates a reporting slot number. In some embodiments, the trigger signaling for the SL-RSRP measurement reporting is part of sidelink control information (SCI), which is to be encoded and transmitted in a physical sidelink control channel (PSCCH) signaling. In some embodiments, the transceiver <NUM> is further configured to transmit, to the second UE <NUM>, a de-modulation reference signal (DMRS) of physical sidelink shared channel (PSSCH) for the purpose of SL-RSRP measurement at the second UE <NUM> and the second UE <NUM> is configured to perform the SL-RSRP measurement based on the transmitted DMRS of the PSSCH.

In some embodiments, the trigger signaling includes a SL-RSRP measurement period or a slot number as a part of sidelink control information (SCI), which is to be encoded and transmitted in a physical sidelink control channel (PSCCH). In some embodiments, the transceiver <NUM> is further configured to transmit, to the second UE <NUM>, a de-modulation reference signal (DMRS) of the PSSCH and the processor <NUM> is configured to request the second UE <NUM> to measure the SL-RSRP measurement result according to the DMRS of the PSSCH. The transceiver <NUM> is further configured to receive, from the second UE <NUM>, the SL-RSRP measurement report via the PSSCH.

The pathloss between the first UE <NUM> and the second UE <NUM> is estimated according to a reference SL transmission power level used for transmitting the PSSCH from the first UE <NUM> to the second UE <NUM>. In some embodiments, the pathloss between the first UE <NUM> and the second UE <NUM> is estimated by calculating the following: the pathloss between the first UE <NUM> and the second UE <NUM> is equal to a reference SL transmission power level used for transmitting the PSSCH from the first UE <NUM> to the second UE <NUM> minus the received SL-RSRP measurement result. In some embodiments, the processor <NUM> is further configured to determine a new SL transmission power level used for transmitting the PSSCH from the first UE <NUM> to the second UE <NUM>. In some embodiments, the new SL transmission power level is determined according to at least one of an estimated pathloss value, a modulation and coding scheme (MCS) level, an allocation of frequency resource blocks (RBs), a size of frequency RBs, and a packet transport block (TB) size. In some embodiments, the reported SL-RSRP measurement result comprises measured SL-RSRP levels, and the measured SL-RSRP levels are averaged via layer <NUM> filtering.

In some embodiments, the processor <NUM> is configured to be triggered, by a trigger signaling received from the first UE <NUM>, to control the transceiver <NUM> to report a sidelink - reference signal received power (SL-RSRP) measurement result and control the transceiver <NUM> to report, to the first UE <NUM>, the SL-RSRP measurement result. Benefits from adopting the proposed method of power control for wireless SL transmissions of some embodiments include: <NUM>. Saving portable UE device's battery power, and this will lead to longer device operating time. Minimizing interference to other surrounding nearby UEs, resulting in better SL system performance and more radio frequency reuse in more areas. Minimizing interference to cellular uplink (UL) base station (BS) receiver and better cellular performance in a UL direction. Better adaptation of SL transmission parameters to wireless channel environment, and this will lead to more reliable SL data transfer, better radio resource utilization, improved data throughput, and possibly shorter data transfer latency.

The trigger signaling indicates a SL-RSRP measurement reporting interval. The trigger signaling for the SL-RSRP measurement reporting is part of a radio resource control (RRC) signaling. In another embodiment which is not part of the claimed invention, the trigger signaling further indicates a reporting slot number. In some embodiments, the trigger signaling for the SL-RSRP measurement reporting is part of sidelink control information (SCI), which is to be encoded and transmitted in a physical sidelink control channel (PSCCH) signaling. In some embodiments, the transceiver <NUM> is further configured to received, from the first UE <NUM>, a de-modulation reference signal (DMRS) of physical sidelink shared channel (PSSCH) for the purpose of SL-RSRP measurement at the second UE <NUM> and the second UE <NUM> is configured to perform the SL-RSRP measurement based on the transmitted DMRS of the PSSCH.

In some embodiments, the trigger signaling includes a SL-RSRP measurement period or a slot number as a part of sidelink control information (SCI), which is to be encoded and transmitted in a physical sidelink control channel (PSCCH). In some embodiments, the transceiver <NUM> is further configured to receive, from the first UE <NUM>, a de-modulation reference signal (DMRS) of the PSSCH and the processor <NUM> is configured to measure the SL-RSRP measurement result according to the DMRS of the PSSCH. The transceiver <NUM> is further configured to transmit, to the first UE <NUM>, the SL-RSRP measurement report via the PSSCH. In some embodiments, a pathloss between the first UE <NUM> and the second UE <NUM> is estimated by calculating the following: the pathloss between the first UE <NUM> and the second UE <NUM> is equal to a reference SL transmission power level used for transmitting the PSSCH from the first UE <NUM> to the second UE <NUM> minus the reported SL-RSRP measurement result.

<FIG> illustrates a method <NUM> for transmission power control of a first UE according to an embodiment of the present disclosure. In some embodiments, the method <NUM> includes: a block <NUM>, sending a trigger signaling to a second UE to request the second UE to report a sidelink - reference signal received power (SL-RSRP) measurement result, a block <NUM>, receiving, from the second UE, the SL-RSRP measurement report, and a block <NUM>, estimating a pathloss between the first UE and the second UE according to the reported SL-RSRP measurement result. Benefits from adopting the proposed method of power control for wireless SL transmissions of some embodiments include: <NUM>. Saving portable UE device's battery power, and this will lead to longer device operating time. Minimizing interference to other surrounding nearby UEs, resulting in better SL system performance and more radio frequency reuse in more areas. Minimizing interference to cellular uplink (UL) base station (BS) receiver and better cellular performance in a UL direction. Better adaptation of SL transmission parameters to wireless channel environment, and this will lead to more reliable SL data transfer, better radio resource utilization, improved data throughput, and possibly shorter data transfer latency.

The trigger signaling indicates a SL-RSRP measurement reporting interval. The trigger signaling for the SL-RSRP measurement reporting is part of a radio resource control (RRC) signaling. In another embodiment which is not part of the claimed invention, the trigger signaling further indicates a reporting slot number. In some embodiments, the trigger signaling for the SL-RSRP measurement reporting is part of sidelink control information (SCI), which is to be encoded and transmitted in a physical sidelink control channel (PSCCH) signaling. In some embodiments, the method further comprises transmitting, to the second UE, a de-modulation reference signal (DMRS) of physical sidelink shared channel (PSSCH) for the purpose of SL-RSRP measurement at the second UE and the second UE is configured to perform the SL-RSRP measurement based on the transmitted DMRS of the PSSCH.

In some embodiments, the trigger signaling includes a SL-RSRP measurement period or a slot number as a part of sidelink control information (SCI), which is to be encoded and transmitted in a physical sidelink control channel (PSCCH). In some embodiments, the method further includes transmitting, to the second UE, a de-modulation reference signal (DMRS) of the PSSCH and requesting the second UE to measure the SL-RSRP measurement result according to the DMRS of the PSSCH. The method further includes receiving, from the second UE, the SL-RSRP measurement report via the PSSCH.

The pathloss between the first UE and the second UE is estimated according to a reference SL transmission power level used for transmitting the PSSCH from the first UE to the second UE. In some embodiments, the pathloss between the first UE and the second UE is estimated by calculating the following: the pathloss between the first UE and the second UE is equal to a reference SL transmission power level used for transmitting the PSSCH from the first UE to the second UE minus the reported SL-RSRP measurement result. In some embodiments, the method further includes determining a new SL transmission power level used for transmitting the PSSCH from the first UE to the second UE. In some embodiments, the new SL transmission power level is determined according to at least one of an estimated pathloss value, a modulation and coding scheme (MCS) level, an allocation of frequency resource blocks (RBs), a size of frequency RBs, and a packet transport block (TB) size. In some embodiments, the reported SL-RSRP measurement result comprises measured SL-RSRP levels, and the measured SL-RSRP levels are averaged via layer <NUM> filtering.

<FIG> illustrates a method <NUM> for transmission power control of a second UE according to an embodiment of the present disclosure. In some embodiments, the method <NUM> includes: a block <NUM>, being triggered, by a trigger signaling received from a first UE, to report a sidelink - reference signal received power (SL-RSRP) measurement result, and a block <NUM>, reporting, to the first UE, the SL-RSRP measurement result. Benefits from adopting the proposed method of power control for wireless SL transmissions of some embodiments include: <NUM>. Saving portable UE device's battery power, and this will lead to longer device operating time. Minimizing interference to other surrounding nearby UEs, resulting in better SL system performance and more radio frequency reuse in more areas. Minimizing interference to cellular uplink (UL) base station (BS) receiver and better cellular performance in a UL direction. Better adaptation of SL transmission parameters to wireless channel environment, and this will lead to more reliable SL data transfer, better radio resource utilization, improved data throughput, and possibly shorter data transfer latency.

The trigger signaling indicates a SL-RSRP measurement reporting interval. The trigger signaling for the SL-RSRP measurement reporting is part of a radio resource control (RRC) signaling. In another embodiment which is not part of the claimed invention, the trigger signaling further indicates a reporting slot number. In some embodiments, the trigger signaling for the SL-RSRP measurement reporting is part of sidelink control information (SCI), which is to be encoded and transmitted in a physical sidelink control channel (PSCCH) signaling. In some embodiments, the method further comprises receiving, from the first UE, a de-modulation reference signal (DMRS) of physical sidelink shared channel (PSSCH) for the purpose of SL-RSRP measurement at the second UE and the second UE is configured to perform the SL-RSRP measurement based on the transmitted DMRS of the PSSCH.

In some embodiments, the trigger signaling includes a SL-RSRP measurement period or a slot number as a part of sidelink control information (SCI), which is to be encoded and transmitted in a physical sidelink control channel (PSCCH). In some embodiments, the method further includes receiving, from the first UE, a de-modulation reference signal (DMRS) of the PSSCH and measuring the SL-RSRP measurement result according to the DMRS of the PSSCH. The method further includes transmitting, to the first UE, the SL-RSRP measurement report via the PSSCH. In some embodiments, a pathloss between the first UE and the second UE is estimated by calculating the following: the pathloss between the first UE and the second UE is equal to a reference SL transmission power level used for transmitting the PSSCH from the first UE to the second UE minus the SL-RSRP measurement result.

<FIG> is a flowchart illustrating a method of controlling UE transmission power in a new radio (NR) sidelink communication according to an embodiment of the present disclosure. <FIG> is an exemplary illustration of a proposed method of UE power control for a NR sidelink communication involving a first UE for transmission, pathloss estimation, and applying new transmission power level and a second UE for received power measurement and providing feedback report according to an embodiment of the present disclosure.

In some embodiments of the present disclosure, a proposed method provides controlling transmission power of SL signals and channels for a first UE (transmit UE1, Tx-UE1) towards at least one second UE (receiver UE2, Rx-UE2) which is configured to receive SL data from the first UE, in reference to diagrams <NUM> and <NUM> in <FIG> and <FIG> respectively. A Tx-UE1 <NUM> first triggers a Rx-UE2 <NUM> to report a sidelink - reference signal received power (SL-RSRP) by indicating a SL-RSRP measurement period / timeframe or reporting slot number as part of sidelink control information (SCI), which is to be encoded and transmitted in PSCCH at an operation <NUM>. A SL-RSRP measurement period / timeframe <NUM> indicated in SCI for the Rx-UE2 <NUM> could be expressed as a number of NR slots, milli-seconds, or number of PSSCH transmissions from the Tx-UE1 <NUM>.

Once the Rx-UE2 <NUM> received the SL-RSRP reporting triggering indicated in PSCCH SCI at the operation <NUM>, the Rx-UE2 <NUM> performs measurements of SL-RSRP level according to the indicated measurement period / timeframe <NUM>. If the timing for which the Rx-UE2 <NUM> can provide SL-RSRP measurement report is expressed as a NR (D2D frame number) direct frame number (DFN) or slot number, the Rx-UE2 <NUM> can perform SL-RSRP measurement on every PSSCH transmitted at an operation <NUM> from the Tx-UE1 <NUM> intended for the Rx-UE2 <NUM>. If the SL-RSRP measurement period / timeframe is expressed as a time length duration or a number of PSSCH transmissions, the Rx-UE2 <NUM> can perform SL-RSRP measurement on every PSSCH transmitted at the operation <NUM> from the Tx-UE1 <NUM> intended for the Rx-UE2 <NUM> during the measurement period / timeframe <NUM>.

Furthermore, if the Tx-UE1 <NUM> transmits more than one PSSCH intended for the Rx-UE2 <NUM> during the measurement period / timeframe, the Rx-UE2 <NUM> can perform SL-RSRP measurement per PSSCH transmission at the operation <NUM> and average across the multiple measured SL-RSRP levels by means of layer <NUM> filtering. If only one PSSCH is transmitted from the Tx-UE1 <NUM> intended for the Rx-UE2 <NUM> during the measurement period / timeframe <NUM>, the Rx-UE2 <NUM> can perform SL-RSRP measurement only on the transmitted PSSCH intended for it and no layer <NUM> filtering or averaging can be applied.

Furthermore, the Rx-UE2 <NUM> can assume a constant transmission power applied across all PSSCH transmissions from the Tx-UE1 <NUM> intended for it after the SL-RSRP reporting triggering at the operation <NUM> and during the measurement period / timeframe <NUM>. In addition, the measurement of SL-RSRP level can be performed by the Rx-UE2 <NUM> based on de-modulation reference signal (DMRS) <NUM> of PSSCH transmitted from the Tx-UE1 <NUM>. Lastly, it is not necessary to indicate an actual transmission power used to transmit PSSCH and/or DMRS from the Tx-UE1 <NUM> for a purpose of SL-RSRP measurement for SL power control.

After the indicated SL-RSRP measurement period / timeframe, the Rx-UE2 <NUM> can report / feedback its measured, and if applicable, filtered final SL-RSRP level via its own PSSCH transmission at an operation <NUM> to the Tx-UE1 <NUM>. If during the SL-RSRP reporting the Rx-UE2 <NUM> also has SL data transport block (TB) to be transmitted to the Tx-UE1 <NUM> in the same slot or subframe, the final SL-RSRP level will be transmitted together with PSSCH in a PSSCH region of SL transmission, but not encoded as part of PSSCH. If during the SL-RSRP reporting the Rx-UE2 <NUM> also has no SL data transport block (TB) to be transmitted to the Tx-UE1 <NUM> in the same slot or subframe, then in this case the final SL-RSRP level will be encoded and transmitted as per PSSCH to the Tx-UE1 <NUM>.

Once the Tx-UE1 <NUM> receives the SL-RSRP report from the Rx-UE2 <NUM>, the Tx-UE1 <NUM> estimates a pathloss value at an operation <NUM> based on the received SL-RSRP report and the transmission power used to transmit PSSCH during the SL-RSRP measurement period / timeframe, according to a simple calculation: pathloss = Tx power used for transmitting PSSCH - reported SL-RSRP level. Subsequently, a new SL transmission power can be determined by the Tx-UE1 <NUM> and applied to the next or future PSSCH transmissions carrying SL data messages intended for the same Rx-UE2 <NUM> in an operation <NUM>. The determination of new SL transmission power can be based on at least one of the estimated pathloss value, selected MCS level, frequency RBs allocation / size, and SL data TB size.

In summary, an aspect (system level) of some embodiments provides a method of controlling transmission power of NR physical sidelink channel and signal for a first UE based on measurement feedback from at least one second UE. The method includes indicating by the first UE in PSCCH SCI to trigger measurement of SL-RSRP level at the second UE, reporting of a measured SL-RSRP level from the second UE to the first UE via PSSCH, and estimating a pathloss value between the first UE and second UE. The method further includes applying newly determined SL transmission power level by the first UE for NR SL transmissions to the second UE. In some embodiments, the indication includes at least a SL-RSRP measurement period / timeframe. In some embodiments, the measurement of SL-RSRP is based on PSSCH-DMRS transmitted from the first UE. In some embodiments, the measurement feedback is conveyed via PSSCH from the second UE. In some embodiments, the pathloss can be estimated by calculating the following: Pathloss = Tx power used for transmitting PSSCH - reported SL-RSRP level. In some embodiments, the new SL transmission power level is determined based on at least one of the estimated pathloss value, MCS level, frequency RBs allocation / size, and packet TB size.

Another aspect (first Tx-UE1) of some embodiments provides a method of controlling transmission power of NR physical sidelink channel and signal for a first UE based on measurement feedback from at least one second UE. The method includes triggering by the first UE of SL-RSRP measurement and reporting from the second UE, receiving from the second UE a SL-RSRP measurement result, and estimating a pathloss between the first and second UEs based on received SL-RSRP value and the reference SL transmission power level used for transmitting PSSCH from the first UE to the second UE. The method further includes determining a new SL transmission power level to be used by the first UE for transmitting PSSCH to the second UE based on at least one of the estimated pathloss value, MCS level, frequency RBs allocation / size, and packet TB size.

Another aspect (second Rx-UE2) of some embodiments provides a method of controlling transmission power of NR physical sidelink channel and signal for a first UE based on measurement feedback from at least one second UE. The method includes receiving a SL-RSRP measurement trigger in PSSCH SCI from the first UE, measuring SL-RSRP level(s) based on DMRS associated with PSSCH(s) transmitted from the first UE, and reporting a final SL-RSRP value in PSSCH to the first UE via PSSCH.

Commercial interests for some embodiments are as follows. Saving portable UE device's battery power, and this will lead to longer device operating time. Minimizing interference to other surrounding nearby UEs, resulting in better SL system performance and more radio frequency reuse in more areas. Minimizing interference to cellular uplink (UL) base station (BS) receiver and better cellular performance in a UL direction. Better adaptation of SL transmission parameters to wireless channel environment, and this will lead to more reliable SL data transfer, better radio resource utilization, improved data throughput, and possibly shorter data transfer latency. Some embodiments of the present disclosure are used by <NUM>-NR chipset vendors, V2X communication system development vendors, automakers including cars, trains, trucks, buses, bicycles, moto-bikes, helmets, and etc., drones (unmanned aerial vehicles), smartphone makers, communication devices for public safety use, AR/VR device maker for example gaming, conference/seminar, education purposes. Some embodiments of the present disclosure are a combination of "techniques/processes" that can be adopted in 3GPP specification to create an end product.

<FIG> is a block diagram of an example system <NUM> for wireless communication according to an embodiment of the present disclosure. Embodiments described herein may be implemented into the system using any suitably configured hardware and/or software. <FIG> illustrates the system <NUM> including a radio frequency (RF) circuitry <NUM>, a baseband circuitry <NUM>, an application circuitry <NUM>, a memory/storage <NUM>, a display <NUM>, a camera <NUM>, a sensor <NUM>, and an input/output (I/O) interface <NUM>, coupled with each other at least as illustrated.

The application circuitry <NUM> may include a circuitry such as, but not limited to, one or more single-core or multi-core processors. The processors may include any combination of general-purpose processors and dedicated processors, such as graphics processors, application processors. The processors may be coupled with the memory/storage and configured to execute instructions stored in the memory/storage to enable various applications and/or operating systems running on the system.

In various embodiments, the baseband circuitry <NUM> may include circuitry to operate with signals that are not strictly considered as being in a baseband frequency. For example, in some embodiments, baseband circuitry may include circuitry to operate with signals having an intermediate frequency, which is between a baseband frequency and a radio frequency.

The RF circuitry <NUM> may enable communication with wireless networks using modulated electromagnetic radiation through a non-solid medium. In various embodiments, the RF circuitry may include switches, filters, amplifiers, etc. to facilitate the communication with the wireless network.

In various embodiments, the RF circuitry <NUM> may include circuitry to operate with signals that are not strictly considered as being in a radio frequency. For example, in some embodiments, RF circuitry may include circuitry to operate with signals having an intermediate frequency, which is between a baseband frequency and a radio frequency.

In various embodiments, the transmitter circuitry, control circuitry, or receiver circuitry discussed above with respect to the user equipment, eNB, or gNB may be embodied in whole or in part in one or more of the RF circuitry, the baseband circuitry, and/or the application circuitry. As used herein, "circuitry" may refer to, be part of, or include an Application Specific Integrated Circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or group), and/or a memory (shared, dedicated, or group) that execute one or more software or firmware programs, a combinational logic circuit, and/or other suitable hardware components that provide the described functionality. In some embodiments, the electronic device circuitry may be implemented in, or functions associated with the circuitry may be implemented by, one or more software or firmware modules.

In some embodiments, some or all of the constituent components of the baseband circuitry, the application circuitry, and/or the memory/storage may be implemented together on a system on a chip (SOC).

The memory/storage <NUM> may be used to load and store data and/or instructions, for example, for system. The memory/storage for one embodiment may include any combination of suitable volatile memory, such as dynamic random access memory (DRAM)), and/or non-volatile memory, such as flash memory.

In various embodiments, the I/O interface <NUM> may include one or more user interfaces designed to enable user interaction with the system and/or peripheral component interfaces designed to enable peripheral component interaction with the system. User interfaces may include, but are not limited to a physical keyboard or keypad, a touchpad, a speaker, a microphone, etc. Peripheral component interfaces may include, but are not limited to, a non-volatile memory port, a universal serial bus (USB) port, an audio jack, and a power supply interface.

In various embodiments, the sensor <NUM> may include one or more sensing devices to determine environmental conditions and/or location information related to the system. In some embodiments, the sensors may include, but are not limited to, a gyro sensor, an accelerometer, a proximity sensor, an ambient light sensor, and a positioning unit. The positioning unit may also be part of, or interact with, the baseband circuitry and/or RF circuitry to communicate with components of a positioning network, e.g., a global positioning system (GPS) satellite.

In various embodiments, the display <NUM> may include a display, such as a liquid crystal display and a touch screen display. In various embodiments, the system <NUM> may be a mobile computing device such as, but not limited to, a laptop computing device, a tablet computing device, a netbook, an ultrabook, a smartphone, a AR/VR glasses, etc. In various embodiments, system may have more or less components, and/or different architectures. Where appropriate, methods described herein may be implemented as a computer program. The computer program may be stored on a storage medium, such as a non-transitory storage medium.

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.

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.

Claim 1:
A first user equipment, UE, (<NUM>) for transmission power control, comprising:
a memory (<NUM>);
a transceiver (<NUM>); and
a processor (<NUM>) coupled to the memory and the transceiver;
wherein the processor is configured to:
control the transceiver to send a trigger signaling to a second UE (<NUM>) to request the second UE to report a sidelink - reference signal received power, SL-RSRP, measurement result;
control the transceiver to receive, from the second UE, the SL-RSRP measurement report; and
estimate a pathloss between the first UE and the second UE according to the reported SL-RSRP measurement result;
the transceiver is further configured to receive, from the second UE, the SL-RSRP measurement report via physical sidelink shared channel, PSSCH;
wherein the trigger signaling indicates a SL-RSRP measurement reporting interval;
characterized in that, the trigger signaling for the SL-RSRP measurement reporting is part of a radio resource control, RRC, signaling; the pathloss between the first UE and the second UE is estimated according to a reference SL transmission power level used for transmitting the PSSCH from the first UE to the second UE.