Sidelink Power Control in Unlicensed Spectrum Managing PSD Limits
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Solution Overview
Problem
Current power control mechanisms for sidelink communications in unlicensed spectrum do not adequately consider power spectral density (PSD) limits, leading to potential interference and instability in mobile communications.
Innovation Solution
Proposed methods involve adjusting the power control formula to include PSD limits, either by excluding or including the sidelink synchronization signal block (S-SSB) in the resource pool, and using time-division or frequency-division multiplexing to manage power distribution among channels, ensuring that the PSD limit is not exceeded.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the existing power control mechanism only restricts maximum transmit power, then the implementation is simple, but the power spectral density limit is not considered leading to potential interference
Solution Approach 1:
The patent changes the power control parameters by introducing PSD limit considerations alongside maximum transmit power restrictions. The power control formula is modified to include both power constraints and spectral density constraints, transforming the single-parameter control into a multi-parameter control system that accounts for both total power and power distribution across frequency bands.
2Object-affected harmful factors
If a new power control mechanism considering PSD limit is implemented, then interference is reduced, but the complexity of power control increases
Solution Approach 1:
The patent segments the power control mechanism into distinct components: maximum transmit power constraints and power spectral density constraints. By separating these control dimensions, the system can independently manage overall power levels and spectral distribution, making the complex multi-constraint problem more manageable through modular control strategies.
3Device complexity
If S-SSB is excluded from SL resource pool, then power control is simpler, but resource utilization efficiency decreases
Solution Approach 1:
The patent introduces dynamic power control for S-SSB transmissions by adjusting transmit power based on pathloss conditions. The system dynamically determines whether to transmit S-SSB at full power or reduced power depending on the measured pathloss, allowing flexible adaptation to different channel conditions while maintaining compliance with PSD limits.
4Reliability
If transmit power is increased to improve communication reliability, then the link quality improves, but the PSD limit may be exceeded causing regulatory non-compliance
Solution Approach 1:
The patent applies preliminary power control adjustments by calculating the required transmit power based on pathloss compensation before actual transmission. The system pre-determines the appropriate power level that achieves reliable communication while staying within PSD constraints, preventing regulatory violations before they occur rather than reacting after exceeding limits.
Data Source
AI summary
Examples pertaining to power control of sidelink (SL) on unlicensed spectrum (SL-U) in mobile communications are described. A user equipment (UE) communicates in a SL-U. The UE performs a transmit power control (TPC) such that a power spectral density (PSD) limit is not exceeded in communicating in the SL-U.