PRS Power Allocation in 5G NR Positioning
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Solution Overview
Problem
Current wireless communication systems, particularly in 5G NR, face challenges in providing effective Positioning Reference Signals (PRS) for accurate UE positioning, especially in environments with high interference and complex propagation conditions.
Innovation Solution
The proposed solution involves mapping PRS to Resource Elements (REs) of a frame structure with enhanced power allocation, where the power used to transmit REs containing PRS is higher than that used for REs without PRS. This includes using comb-k patterns at both sub-carrier and Resource Block (RB) levels, and spatial multiplexing techniques to boost PRS power while maintaining overall transmission power within constraints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PRS is transmitted with normal power allocation, then overall transmission power efficiency is maintained, but PRS hearability and positioning accuracy deteriorate
Solution Approach 1:
The patent applies different power allocation strategies to different Resource Elements based on their function. REs containing PRS are allocated higher power than REs containing data or control information. This local quality differentiation ensures that PRS receives enhanced power specifically where needed for positioning accuracy, while other REs maintain normal power levels for efficient overall transmission.
Solution Approach 2:
The network configures PRS transmission power levels and mapping patterns in advance through system information blocks and RRC signaling. The UE is pre-informed about the comb-k patterns and power allocation rules, allowing it to properly configure its receiver settings before actual positioning measurements occur, ensuring optimal PRS reception without requiring real-time power adjustments.
2Measurement precision
If power is boosted for PRS transmission, then positioning accuracy is improved, but overall transmission power constraints are challenged
Solution Approach 1:
The patent segments the frequency domain into different Resource Elements using comb-k patterns at both sub-carrier and Resource Block levels. This segmentation allows selective power boosting of only those REs containing PRS while maintaining normal power for other REs. The segmentation approach enables precise power control at the RE level rather than requiring uniform power increase across the entire transmission.
Solution Approach 2:
Instead of uniformly increasing power across all transmissions, the patent applies partial power boosting only to the specific REs containing PRS. This partial action approach provides sufficient power for accurate positioning measurements while avoiding excessive overall power consumption. The comb-k pattern mapping ensures that PRS REs receive the necessary power enhancement without affecting the entire transmission budget.
3Reliability
If comb-k patterns are used for PRS mapping, then PRS separation from other signals is improved, but frequency domain complexity increases
Solution Approach 1:
The patent employs comb-k patterns that segment the frequency domain into regular intervals, separating PRS from data and control signals in a systematic manner. The comb-k structure creates consistent spacing between PRS REs, making them distinguishable through simple correlation processing at the UE side. This segmentation approach provides reliable signal separation while maintaining predictable and manageable complexity through standardized mapping rules.
Data Source
AI summary
A method, for a base station, for transmitting Position Reference Signals (PRS) in a wireless communication system is provided. The method comprises mapping PRS to Resource Elements (REs) of a frame structure, and transmitting the frame structure such that the power used to transmit REs containing PRS is higher than the power used to transmit REs not containing PRS. Methods, for a User Equipment (UE), for transmitting PRS in a wireless communication system are also provided. One method comprises measuring the signal strength from one or more base stations, and transmitting PRS with a power determined based on the measurements. Another method comprises receiving signaling from a base station, and transmitting PRS with a power determined based on the signaling.