WO2019153114A1

WO2019153114A1 - User equipment and method of wireless communication of same

Info

Publication number: WO2019153114A1
Application number: PCT/CN2018/075387
Authority: WO
Inventors: Huei-Ming Lin; Hai Tang
Original assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Current assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Priority date: 2018-02-06
Filing date: 2018-02-06
Publication date: 2019-08-15
Anticipated expiration: 2020-08-06
Also published as: CN111466139A; CN111466139B

Abstract

A user equipment and a method of wireless communication of the same are provided. The user equipment includes a memory and a processor coupled to the memory. The processor is configured to perform a direct sidelink communication to at least one second user equipment, receive, from the at least one second user equipment, a power control command, and adjust, with a first priority, on a forward sidelink communication, a transmit power level to the at least one second user equipment based on the power control command.

Description

USER EQUIPMENT AND METHOD OF WIRELESS COMMUNICATION OF SAME BACKGROUND OF DISCLOSURE

1. Field of Disclosure

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

2. Description of Related Art

In a direct wireless communication system such as device-to-device (D2D) and vehicle-to-everything (V2X) , many user equipments (UEs) are portable devices with limited battery power/capacity. According to 3rd generation partnership project (3GPP) long term evolution (LTE) sidelink technology developed so far in Release 12 to Release 14 for D2D and V2X communications, UEs are required to transmit at maximum allowable power over an LTE sidelink such as PC5 interface for direct communication between UE nodes. For UEs with limited battery capacity, this is not a power efficient method of communicating when UEs are in close proximity or next to each other. For UEs with plugged in power supply (e.g. devices connected to vehicle batteries and road side units or infrastructures) , an excessive transmission power would simply create unnecessary interference to UEs outside a required communication range and thus limiting system capacity and a number of users accommodated within a geographical area. Furthermore, by constantly transmitting at maximum output power, it may also adversely affect achievable throughput if the UE wrongly selects modulation type, transport block size, or size of sidelink resources that are too high or too low. Even when a transmitting UE is able to obtain some kind of power control or power setting indication explicitly or implicitly from a receiving UE, it may still make a sub-optimal selection of values for the aforementioned list of transmission parameters.

SUMMARY

An object of the present disclosure is to propose a user equipment (UE) and a method of wireless communication of the same capable of selecting and adjusting of transmission related parameters in direct wireless communication over a sidelink interface

In a first aspect of the present disclosure, a user equipment for wireless communication includes a memory and a processor coupled to the memory. The processor is configured to perform a direct sidelink communication to at least one second user equipment, receive, from the at least one second user equipment, a power control command, and adjust, with a first priority, on a forward sidelink communication, a transmit power level to the at least one second user equipment based on the power control command.

According to an embodiment in conjunction to the first aspect of the present disclosure, the processor is configured to increase the transmit power level when a value of the power control command is greater than 0dB and a value of a power headroom of the user equipment is greater than or equal to the value of the power control command.

According to an embodiment in conjunction to the first aspect of the present disclosure, the processor is configured to reduce the transmit power level when the value of the power control command is less than 0dB and a transmission from the user equipment to the at least one second user equipment is a retry transmission.

According to an embodiment in conjunction to the first aspect of the present disclosure, the processor is configured to transmit a sidelink resource to the at least one second user equipment and reduce a size of the sidelink resource with a second priority.

According to an embodiment in conjunction to the first aspect of the present disclosure, the processor is configured to transmit an energy per resource element (EPRE) to the at least one second user equipment and reduce the size of the sidelink resource and increase the EPRE when a value of the power control command is greater than 0dB, a value of a power headroom of the user equipment is less than the value of the power control command, and a transmission from the user equipment to the at least one second user equipment is a retry transmission.

According to an embodiment in conjunction to the first aspect of the present disclosure, the size of the sidelink resource includes at least one of a number of a physical resource block (PRB) in frequency domain, a number of a slot in time domain, and a number of a symbol in time domain.

According to an embodiment in conjunction to the first aspect of the present disclosure, the processor is configured to increase the size of the sidelink resource with a third priority.

According to an embodiment in conjunction to the first aspect of the present disclosure, the processor is configured to transmit an energy per resource element (EPRE) to the at least one second user equipment and increase the size of the sidelink resource and reduce the EPRE when a value of the power control command is less than 0dB, a transmission from the user equipment to the at least one second user equipment is an initial transmission, and the user equipment meets at least one condition of an adjacent PRB not reserved, a channel busy ratio (CBR) of a sidelink resource pool less than 80%, a limit of a occupancy ratio of the sidelink resource pool not reached, and a buffer status report (BSR) of the user equipment greater than a predetermined value.

According to an embodiment in conjunction to the first aspect of the present disclosure, the processor is configured to adjust at least one of a modulation type and a transport block size (TBS) with a fourth priority.

According to an embodiment in conjunction to the first aspect of the present disclosure, the processor is configured to reduce at least one of the modulation type and the TBS when a value of the power control command is greater than 0dB, a value of a power headroom of the user equipment is less than the value of the power control command, and a transmission from the user equipment to the at least one second user equipment is an initial transmission.

According to an embodiment in conjunction to the first aspect of the present disclosure, the processor is configured to reduce a modulation and coding scheme (MCS) by one level if the value of the power control command is equal to 2dB.

According to an embodiment in conjunction to the first aspect of the present disclosure, the processor is configured to scale the TBS base on the power control command such that a code rate is decreased proportionally.

According to an embodiment in conjunction to the first aspect of the present disclosure, the processor is configured to increase at least one of the modulation type and the TBS when a value of the power control command is less than 0dB, a transmission from the user equipment to the at least one second user equipment is an initial transmission, and the user equipment meets at least one condition of an adjacent PRB reserved, a channel busy ratio (CBR) of a sidelink resource pool greater than or equal to 80%, a limit of a occupancy ratio of the sidelink resource pool reached, and a buffer status report (BSR) of the user equipment less than a predetermined value.

According to an embodiment in conjunction to the first aspect of the present disclosure, the processor is configured to increase a modulation and coding scheme (MCS) by one level if the value of the power control command is equal to -2dB.

According to an embodiment in conjunction to the first aspect of the present disclosure, the processor is configured to scale the TBS base on the power control command such that a code rate is increased proportionally.

According to an embodiment in conjunction to the first aspect of the present disclosure, the processor is configured to calculate a power headroom of the user equipment for slot i according to the followings:

Power_headroom (i) = min {Pue, max (i) , Pcmax (i) } -Pue (lastTx) , where

Pue (lastTx) = a total output power of the user equipment in a last transmission,

Pcmax (i) = a maximum configured output power of the user equipment in slot i for a serving cell when in-network coverage or a maximum pre-configured output power of the user equipment in slot i when out-of-network coverage, and

Pue, max (i) = a maximum output power of the user equipment in slot i according to a power class definition for a frequency band.

In a second aspect of the present disclosure, method of wireless communication of a user equipment includes performing a direct sidelink communication to at least one second user equipment, receiving, from the at least one second user equipment, a power control command, and adjusting, with a first priority, on a forward sidelink communication, a transmit power levelto the at least one second user equipment based on the power control command.

According to another embodiment in conjunction to the second aspect of the present disclosure, the method further includes increasing the transmit power level when a value of the power control command is greater than 0dB and a value of a power headroom of the user equipment is greater than or equal to the value of the power control command.

According to another embodiment in conjunction to the second aspect of the present disclosure, the method further includes reducing the transmit power level when the value of the power control command is less than 0dB and a transmission from the user equipment to the at least one second user equipment is a retry transmission.

According to another embodiment in conjunction to the second aspect of the present disclosure, the method further includes transmitting a sidelink resource to the at least one second user equipment and reducing a size of the sidelink resource with a second priority.

According to another embodiment in conjunction to the second aspect of the present disclosure, the method further includes transmitting an energy per resource element (EPRE) to the at least one second user equipment and reducing the size of the sidelink resource and increasing the EPRE when a value of the power control command is greater than 0dB, a value of a power headroom of the user equipment is less than the value of the power control command, and a transmission from the user equipment to the at least one second user equipment is a retry transmission.

According to another embodiment in conjunction to the second aspect of the present disclosure, the size of the sidelink resource includes at least one of a number of a physical resource block (PRB) in frequency domain, a number of a slot in time domain, and a number of a symbol in time domain.

According to another embodiment in conjunction to the second aspect of the present disclosure, the method further includes increasing the size of the sidelink resource with a third priority.

According to another embodiment in conjunction to the second aspect of the present disclosure, the method further includes transmitting an energy per resource element (EPRE) to the at least one second user equipment and increasing the size of the sidelink resource and reducing the EPRE when a value of the power control command is less than 0dB, a transmission from the user equipment to the at least one second user equipment is an initial transmission, and the user equipment meets at least one condition of an adjacent PRB not reserved, a channel busy ratio (CBR) of a sidelink resource pool less than 80%, a limit of a occupancy ratio of the sidelink resource pool not reached, and a buffer status report (BSR) of the user equipment greater than a predetermined value.

According to another embodiment in conjunction to the second aspect of the present disclosure, the method further includes adjusting at least one of a modulation type and a transport block size (TBS) with a fourth priority.

According to another embodiment in conjunction to the second aspect of the present disclosure, the method further includes reducing at least one of the modulation type and the TBS when a value of the power control command is greater than 0dB, a value of a power headroom of the user equipment is less than the value of the power control command, and a transmission from the user equipment to the at least one second user equipment is an initial transmission.

According to another embodiment in conjunction to the second aspect of the present disclosure, the method further includes reducing a modulation and coding scheme (MCS) by one level if the value of the power control command is equal to 2dB.

According to another embodiment in conjunction to the second aspect of the present disclosure, the method further includes scaling the TBS base on the power control command such that a code rate is decreased proportionally.

According to another embodiment in conjunction to the second aspect of the present disclosure, the method further includes increasing at least one of the modulation type and the TBS when a value of the power control command is less than 0dB, a transmission from the user equipment to the at least one second user equipment is an initial transmission, and the user equipment meet at least one condition of an adjacent PRB reserved, a channel busy ratio (CBR) of a sidelink resource pool greater than or equal to 80%, a limit of a occupancy ratio of the sidelink resource pool reached, and a buffer status report (BSR) of the user equipment less than a predetermined value.

According to another embodiment in conjunction to the second aspect of the present disclosure, the method further includes increasing a modulation and coding scheme (MCS) by one level if the value of the power control command is equal to -2dB.

According to another embodiment in conjunction to the second aspect of the present disclosure, the method further includes scaling the TBS base on the power control command such that a code rate is increased proportionally.

According to another embodiment in conjunction to the second aspect of the present disclosure, the method further includes calculating a power headroom of the user equipment for slot i according to the followings:

Power_headroom (i) = min {Pue, max (i) , Pcmax (i) } -Pue (lastTx) , where

In the embodiment of the present disclosure, the user equipment and the method of wireless communication of the same are capable of selecting and adjusting of transmission related parameters, such that the user equipment could save battery, perform long operation time, and/or have good operating performance from less interference.

BRIEF DESCRIPTION OF DRAWINGS

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

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

FIG. 2 is a scenario of vehicle-to-everything (V2X) communication according to an embodiment of the present disclosure.

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

FIG. 4 is a flowchart illustrating another method of wireless communication according to the present disclosure, from an aspect of operation of a user equipment for transmitting signals.

FIG. 5 is a flowchart illustrating still another method of wireless communication according to the present disclosure, from an aspect of operation of a user equipment for transmitting signals.

FIG. 6 is a flowchart illustrating another further method of wireless communication according to the present disclosure, from an aspect of operation of a user equipment for transmitting signals.

DETAILED DESCRIPTION OF EMBODIMENTS

Embodiments of the present disclosure are described in detail with the technical matters, structural features, achieved objects, and effects with reference to the accompanying drawings as follows. Specifically, the terminologies in the embodiments of the present disclosure are merely for describing the purpose of the certain embodiment, but not to limit the disclosure.

FIG. 1 illustrates that, in some embodiments, a user equipment 100 for wireless communication includes a memory 102 and a processor 104 coupled to the memory 102. The processor 104 is configured to perform a direct sidelink communication to at least one second user equipment 200, receive, from the at least one second user equipment 200, a power control command, and adjust, with a first priority, on a forward sidelink communication, a transmit power level to the at least one second user equipment 200 based on the power control command, such that the user equipment 100 could save battery, perform long operation time, and/or have good operating performance from less interference. In some embodiments, the user equipment 100 may be a user equipment for transmitting signals and the at least one second user equipment 200 may be a user equipment for receiving signals. In some embodiments, the direct sidelink communication between the user equipment 100 and the at least one second user equipment 200 over a sidelink interface such as a PC5 interface may relate to device-to-device (D2D) and/or vehicle-to-everything (V2X) communication according to long term evolution (LTE) sidelink technology developed under 3rd generation partnership project (3GPP) and/or 5th generation new radio (5G-NR) radio access technology.

In some embodiments, the memory 102 may include read-only memory (ROM) , random access memory (RAM) , flash memory, memory card, storage medium and/or other storage device. The processor 104 may include application-specific integrated circuit (ASIC) , other chipset, logic circuit and/or data processing device. The processor 104 may also include baseband circuitry to process radio frequency signals. When the embodiments are implemented in software, the techniques described herein can be implemented with modules (e.g., procedures, functions, and so on) that perform the functions described herein. The modules can be stored in memory 102 and executed by processor 104. The memory 102 can be implemented within the processor 104 or external to the processor 104 in which case those can be communicatively coupled to the processor 104 via various means as is known in the art.

FIG. 2 illustrates that, in some embodiments, the communication between the user equipment 100 and the user equipment 200 relates to V2X communication including vehicle-to-vehicle (V2V) , vehicle-to-pedestrian (V2P) , and vehicle-to-infrastructure/network (V2I/N) according to LTE sidelink technology developed under 3GPP and/or 5G-NR radio access technology. The

user equipments

100 and 200 are communicated with each other directly via a sidelink interface such as a PC5 interface.

FIG. 3 illustrates that, a method 300 of wireless communication according to the present disclosure, from an aspect of operation of the user equipment 100 for transmitting signals. The method 300 includes: at block 302, performing a direct sidelink communication to at least one second user equipment 200, at block 304, receiving, from the at least one second user equipment 200, a power control command, and at block 306, adjusting, with a first priority, on a forward sidelink communication, a transmit power level to the at least one second user equipment 200 based on the power control command, such that the user equipment 100 could save battery, perform long operation time, and/or have good operating performance from less interference. In some embodiments, the processor 104 is configured to increase the transmit power level when a value of the power control command is greater than 0dB and a value of a power headroom of the user equipment 100 is greater than or equal to the value of the power control command. The processor 104 is further configured to reduce the transmit power level when the value of the power control command is less than 0dB and a transmission from the user equipment 100 to the at least one second user equipment 200 is a retry transmission.

FIGS. 1 and 4 illustrate that, in some embodiments, the processor 104 is further configured to transmit a sidelink resource to the at least one second user equipment 200 and reduce a size of the sidelink resource with a second priority. A method 400 of wireless communication according to the present disclosure, from an aspect of operation of the user equipment 100 for transmitting signals is further illustrated. The method 400 includes: at block 402, performing a direct sidelink communication to at least one second user equipment 200, at block 404, receiving, from the at least one second user equipment 200, a power control command, at block 406, adjusting, with a first priority, on a forward sidelink communication, a transmit power level to the at least one second user equipment 200 based on the power control command, and at block 408, transmitting a sidelink resource to the at least one second user equipment 200 and reducing a size of the sidelink resource with a second priority, such that the user equipment 100 could save battery, perform long operation time, and/or have good operating performance from less interference.

In some embodiments, the processor 104 is configured to transmit at an energy per resource element (EPRE) to the at least one second user equipment 200 and reduce the size of the sidelink resource and increase the EPRE when a value of the power control command is greater than 0dB, a value of a power headroom of the user equipment is less than the value of the power control command, and a transmission from the user equipment 100 to the at least one second user equipment 200 is a retry transmission. The size of the sidelink resource includes at least one of a number of a physical resource block (PRB) in frequency domain, a number of a slot in time domain, and a number of a symbol in time domain.

FIGS. 1 and 5 illustrate that, in some embodiments, the processor 104 is further configured to increase the size of the sidelink resource with a third priority. A method 500 of wireless communication according to the present disclosure, from an aspect of operation of the user equipment 100 for transmitting signals is further illustrated. The method 500 includes: at block 502, performing a direct sidelink communication to at least one second user equipment 200, at block 504, receiving, from the at least one second user equipment 200, a power control command, at block 506, adjusting, with a first priority, on a forward sidelink communication, a transmit power level to the at least one second user equipment 200 based on the power control command, at block 508, transmitting a sidelink resource to the at least one second user equipment 200 and reducing a size of the sidelink resource with a second priority, and at block 510, increasing the size of the sidelink resource with a third priority, such that the user equipment 100 could save battery, perform long operation time, and/or have good operating performance from less interference.

In some embodiments, the processor 104 is configured to transmit at an energy per resource element (EPRE) to the at least one second user equipment 200 and increase the size of the sidelink resource and reduce the EPRE when a value of the power control command is less than 0dB, a transmission from the user equipment 100 to the at least one second user equipment 200 is an initial transmission, and the user equipment 100 meets at least one condition of an adjacent PRB not reserved, a channel busy ratio (CBR) of a sidelink resource pool less than 80%, a limit of a occupancy ratio of the sidelink resource pool not reached, and a buffer status report (BSR) of the user equipment 100 greater than a predetermined value.

FIGS. 1 and 6 illustrate that, in some embodiments, the processor 104 is further configured to adjust at least one of a modulation type and a transport block size (TBS) with a fourth priority. A method 600 of wireless communication according to the present disclosure, from an aspect of operation of the user equipment 100 for transmitting signals is further illustrated. The method 600 includes: at block 602, performing a direct sidelink communication to at least one second user equipment 200, at block 604, receiving, from the at least one second user equipment 200, a power control command, at block 606, adjusting, with a first priority, on a forward sidelink communication, a transmit power level to the at least one second user equipment 200 based on the power control command, at block 608, transmitting a sidelink resource to the at least one second user equipment 200 and reducing a size of the sidelink resource with a second priority, at block 610, increasing the size of the sidelink resource with a third priority, and at block 612, adjusting at least one of a modulation type and a transport block size (TBS) with a fourth priority, such that the user equipment 100 could save battery, perform long operation time, and/or have good operating performance from less interference.

In some embodiments, the processor 104 is configured to reduce at least one of the modulation type and the TBS when a value of the power control command is greater than 0dB, a value of a power headroom of the user equipment 100 is less than the value of the power control command, and a transmission from the user equipment 100 to the at least one second user equipment 200 is an initial transmission. The processor 104 is configured to reduce a modulation and coding scheme (MCS) by one level if the value of the power control command is equal to 2dB. The processor 104 is configured to scale the TBS base on the power control command such that a code rate is decreased proportionally. The processor 104 is configured to increase at least one of the modulation type and the TBS when a value of the power control command is less than 0dB, a transmission from the user equipment 100 to the at least one second user equipment 200 is an initial transmission, and the user equipment 100 meets at least one condition of an adjacent PRB reserved, a channel busy ratio (CBR) of a sidelink resource pool greater than or equal to 80%, a limit of a occupancy ratio of the sidelink resource pool reached, and a buffer status report (BSR) of the user equipment 100 less than a predetermined value.

In some embodiments, the processor 104 is configured to increase a modulation and coding scheme (MCS) by one level if the value of the power control command is equal to -2dB. The processor 104 is configured to scale the TBS base on the power control command such that a code rate is increased proportionally. The processor 104 is configured to calculate a power headroom of the user equipment 100 for slot i according to the followings:

Power_headroom (i) = min {Pue, max (i) , Pcmax (i) } -Pue (lastTx) , where

Pcmax (i) = a maximum configured output power of the user equipment 100 in slot i for a serving cell when in-network coverage or a maximum pre-configured output power of the user equipment 100 in slot i when out-of-network coverage, and

Pue, max (i) = a maximum output power of the user equipment 100 in slot i according to a power class definition for a frequency band.

In the embodiment of the present disclosure, the user equipment and the method of wireless communication of the same are capable of selecting and adjusting of transmission related parameters, such that the user equipment could save battery, perform long operation time from reduced wireless transmit power control/setting, perform good link adaptation from adjustments of transmission related parameters to lead to high throughput and thus good user experience and/or have good operating performance and accommodate more users from reduced transmission interference.

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

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

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

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

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

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

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

Claims

A user equipment for wireless communication, comprising:

a memory; and

a processor coupled to the memory and configured to:

perform a direct sidelink communication to at least one second user equipment;

receive, from the at least one second user equipment, a power control command; and

adjust, with a first priority, on a forward sidelink communication, a transmit power level to the at least one second user equipment based on the power control command.
The user equipment of claim 1, wherein the processor is configured to increase the transmit power level when a value of the power control command is greater than 0dB and a value of a power headroom of the user equipment is greater than or equal to the value of the power control command.
The user equipment of claim 1, wherein the processor is configured to reduce the transmit power level when the value of the power control command is less than 0dB and a transmission from the user equipment to the at least one second user equipment is a retry transmission.
The user equipment of claim 1, wherein the processor is configured to transmit a sidelink resource to the at least one second user equipment and reduce a size of the sidelink resource with a second priority.
The user equipment of claim 4, wherein the processor is configured to transmit an energy per resource element (EPRE) to the at least one second user equipment and reduce the size of the sidelink resource and increase the EPRE when a value of the power control command is greater than 0dB, a value of a power headroom of the user equipment is less than the value of the power control command, and a transmission from the user equipment to the at least one second user equipment is a retry transmission.
The user equipment of claim 5, wherein the size of the sidelink resource comprises at least one of a number of a physical resource block (PRB) in frequency domain, a number of a slot in time domain, and a number of a symbol in time domain.
The user equipment of claim 4, wherein the processor is configured to increase the size of the sidelink resource with a third priority.
The user equipment of claim 7, wherein the processor is configured to transmit an energy per resource element (EPRE) to the at least one second user equipment and increase the size of the sidelink resource and reduce the EPRE when a value of the power control command is less than 0dB, a transmission from the user equipment to the at least one second user equipment is an initial transmission, and the user equipment meets at least one condition of an adjacent PRB not reserved, a channel busy ratio (CBR) of a sidelink resource pool less than 80%, a limit of a occupancy ratio of the sidelink resource pool not reached, and a buffer status report (BSR) of the user equipment greater than a predetermined value.
The user equipment of claim 7, wherein the processor is configured to adjust at least one of a modulation type and a transport block size (TBS) with a fourth priority.
The user equipment of claim 9, wherein the processor is configured to reduce at least one of the modulation type and the TBS when a value of the power control command is greater than 0dB, a value of a power headroom of the user equipment is less than the value of the power control command, and a transmission from the user equipment to the at least one second user equipment is an initial transmission.
The user equipment of claim 10, wherein the processor is configured to reduce a modulation and coding scheme (MCS) by one level if the value of the power control command is equal to 2dB.
The user equipment of claim 10, wherein the processor is configured to scale the TBS base on the power control command such that a code rate is decreased proportionally.
The user equipment of claim 9, wherein the processor is configured to increase at least one of the modulation type and the TBS when a value of the power control command is less than 0dB, a transmission from the user equipment to the at least one second user equipment is an initial transmission, and the user equipment meets at least one condition of an adjacent PRB reserved, a CBR of a sidelink resource pool greater than or equal to 80%, a limit of a occupancy ratio of the sidelink resource pool reached, a limit of a BSR of the user equipment less than a predetermined value.
The user equipment of claim 13, wherein the processor is configured to increase a MCS by one level if the value of the power control command is equal to -2dB.
The user equipment of claim 13, wherein the processor is configured to scale the TBS base on the power control command such that a code rate is increased proportionally.
The user equipment of claim 1, wherein the processor is configured to calculate a power headroom of the user equipment for slot i according to the followings:

Power_headroom (i) = min {Pue, max (i) , Pcmax (i) } -Pue (lastTx) , where

Pue (lastTx) = a total output power of the user equipment in a last transmission,

Pcmax (i) = a maximum configured output power of the user equipment in slot i for a serving cell when in-network coverage or a maximum pre-configured output power of the user equipment in slot i when out-of-network coverage, and

Pue, max (i) = a maximum output power of the user equipment in slot i according to a power class definition for a frequency band.
A method of wireless communication of a user equipment, comprising:

performing a direct sidelink communication to at least one second user equipment;

receiving, from the at least one second user equipment, a power control command; and

adjusting, with a first priority, on a forward sidelink communication, a transmit power level to the at least one second user equipment based on the power control command.
The method of claim 17, further comprising increasing the transmit power level when a value of the power control command is greater than 0dB and a value of a power headroom of the user equipment is greater than or equal to the value of the power control command.
The method of claim 17, further comprising reducing the transmit power level when the value of the power control command is less than 0dB and a transmission from the user equipment to the at least one second user equipment is a retry transmission.
The method of claim 17, further comprising transmitting a sidelink resource to the at least one second user equipment and reducing a size of the sidelink resource with a second priority.
The method of claim 20, further comprising transmitting an EPRE to the at least one second user equipment and reducing the size of the sidelink resource and increasing the EPRE when a value of the power control command is greater than 0dB, a value of a power headroom of the user equipment is less than the value of the power control command, and a transmission from the user equipment to the at least one second user equipment is a retry transmission.
The method of claim 21, wherein the size of the sidelink resource comprises at least one of a number of a PRB in frequency domain, a number of a slot in time domain, and a number of a symbol in time domain.
The method of claim 20, wherein further comprising increasing the size of the sidelink resource with a third priority.
The method of claim 23, further comprising transmitting an EPRE to the at least one second user equipment and increasing the size of the sidelink resource and reducing the EPRE when a value of the power control command is less than 0dB, a transmission from the user equipment to the at least one second user equipment is an initial transmission, and the user equipment meets at least one condition of an adjacent PRB not reserved, a CBR of a sidelink resource pool less than 80%, a limit of a occupancy ratio of the sidelink resource pool not reached, and a BSR of the user equipment greater than a predetermined value.
The method of claim 23, further comprising adjusting at least one of a modulation type and a TBS with a fourth priority.
The method of claim 25, further comprising reducing at least one of the modulation type and the TBS when a value of the power control command is greater than 0dB, a value of a power headroom of the user equipment is less than the value of the power control command, and a transmission from the user equipment to the at least one second user equipment is an initial transmission.
The method of claim 26, further comprising reducing a MCS by one level if the value of the power control command is equal to 2dB.
The method of claim 26, further comprising scaling the TBS base on the power control command such that a code rate is decreased proportionally.
The method of claim 25, further comprising increasing at least one of the modulation type and the TBS when a value of the power control command is less than 0dB, a transmission from the user equipment to the at least one second user equipment is an initial transmission, and the user equipment meets at least one condition of an adjacent PRB reserved, a CBR of a sidelink resource pool greater than or equal to 80%, a limit of a occupancy ratio of the sidelink resource pool reached, and a BSR of the user equipment less than a predetermined value.
The method of claim 29, further comprising increasing a MCS by one level if the value of the power control command is equal to -2dB.
The method of claim 29, further comprising scaling the TBS base on the power control command such that a code rate is increased proportionally.
The method of claim 17, further comprising calculating a power headroom of the user equipment for slot i according to the followings:

Power_headroom (i) = min {Pue, max (i) , Pcmax (i) } -Pue (lastTx) , where

Pue (lastTx) = a total output power of the user equipment in a last transmission,

Pcmax (i) = a maximum configured output power of the user equipment in slot i for a serving cell when in-network coverage or a maximum pre-configured output power of the user equipment in slot i when out-of-network coverage, and

Pue, max (i) = a maximum output power of the user equipment in slot i according to a power class definition for a frequency band.