Sidelink Closed-Loop Power Control for V2X Reliability
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Solution Overview
Problem
Current 5G communication systems lack an effective method for controlling transmission power between user equipment (UEs) in sidelink communications, particularly in scenarios requiring high reliability and data rates, such as vehicle-to-everything (V2X) communications, where traditional LTE D2D and V2X technologies do not support closed-loop power control.
Innovation Solution
A sidelink closed-loop transmission power control method and device are introduced to manage transmission power between UEs, utilizing control information and data information transmission, with the ability to determine whether to perform closed-loop power control based on communication type and coverage of a base station, and employing accumulative or absolute transmission power control modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional LTE D2D and V2X technologies are used for sidelink communications, then device compatibility and existing infrastructure support are maintained, but transmission power control effectiveness and reliability are insufficient
Solution Approach 1:
The patent implements a closed-loop power control mechanism where the receiving UE measures the received signal strength (e.g., RSRP) of the sidelink signal and feeds back this measurement to the transmitting UE. The transmitting UE then adjusts its transmission power based on this feedback to achieve reliable communication while managing interference effectively.
Solution Approach 2:
The transmitting UE autonomously adjusts its own transmission power based on feedback from the receiving UE without requiring direct intervention from the base station for each power adjustment decision, enabling self-service power control that improves reliability while reducing network overhead.
2Productivity
If transmission power is increased to support high data rates in V2X scenarios, then data rate and communication distance are improved, but interference to other users and path loss mitigation become problematic
Solution Approach 1:
The receiving UE provides feedback information including measured signal strength to the transmitting UE, enabling the transmitter to optimize its power level to achieve high data rates without excessive interference. This closed-loop mechanism allows dynamic power adjustment matched to actual channel conditions.
Solution Approach 2:
The transmitting UE dynamically changes its transmission power parameter based on feedback from the receiving UE and channel conditions, adjusting the power level to maintain high data rates while adapting to varying interference environments and path loss conditions in V2X scenarios.
3Reliability
If closed-loop power control is implemented in sidelink communications, then transmission power control effectiveness is improved, but signaling overhead and control information requirements increase
Solution Approach 1:
The patent utilizes existing uplink control channels (such as PUCCH or PUSCH) to carry the power control feedback from receiving UE to transmitting UE, rather than creating dedicated feedback channels. This approach achieves effective closed-loop power control while minimizing additional signaling overhead by leveraging existing communication infrastructure.
4Reliability
If dynamic transmission power control is applied to support high reliability in V2X, then communication reliability and data rate are enhanced, but energy consumption and system complexity increase
Solution Approach 1:
The closed-loop power control mechanism is selectively applied based on communication requirements - for example, activating it for high-reliability V2X communications while potentially using simpler open-loop control for less critical traffic. This partial application approach achieves high reliability where needed while avoiding unnecessary energy consumption in scenarios where full closed-loop control is not required.
Data Source
AI summary
The present disclosure provides a method, performed by a sidelink user equipment (UE), of controlling a transmission power in a wireless communication system, the method including: obtaining, by a first sidelink UE, control information for determining whether to perform a closed loop power control (CLPC) process; transmitting a sidelink measurement signal to a second sidelink UE based on a result of the determining; receiving a sidelink signal transmitted according to a transmission power value set based on the sidelink measurement signal; and providing transmission power control (TPC) command information based on a transmission power value of the received sidelink signal.