Sub-PRB DMRS Phase Rotation for Two-Tone Uplink Efficiency
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Solution Overview
Problem
Current wireless communication systems face inefficiencies in uplink spectrum allocation, particularly with minimum resource allocation granularity being one physical resource block (PRB), which limits power efficiency and increases complexity in phase rotation compensation for two-tone modulation schemes.
Innovation Solution
The generation of a one-tone demodulation reference signal (DMRS) based on sequences and determination of phase rotation using a tone index for sub-PRB granularity allocations, allowing for efficient resource utilization and simplified phase compensation in two-tone modulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If minimum resource allocation granularity is set to one PRB, then resource allocation is simple, but uplink spectrum efficiency is reduced and power efficiency deteriorates
Solution Approach 1:
The patent segments a physical resource block into multiple subcarriers, allowing allocation at a finer granularity (sub-PRB level). This enables more flexible resource distribution among multiple users, improving spectrum efficiency while maintaining manageable allocation complexity through structured subcarrier grouping.
2Productivity
If two-tone modulation is used for sub-PRB allocation, then spectrum efficiency improves, but receiver complexity increases due to phase rotation compensation requirements
Solution Approach 1:
The patent applies preliminary phase rotation compensation at the transmitter side, where the phase rotation is determined based on the tone index before transmission. This pre-computed phase rotation simplifies the receiver's task, as it only needs to apply the predetermined compensation rather than performing complex real-time analysis, thus reducing receiver complexity while maintaining the benefits of two-tone modulation.
3Power
If one-tone DMRS is used for sub-PRB allocation, then PAPR is reduced, but phase continuity maintenance becomes more difficult
Solution Approach 1:
The patent incorporates feedback mechanisms where the receiver determines phase rotation based on the actual tone index used in the transmission. This feedback loop allows the system to adapt and maintain phase continuity automatically, compensating for the simplicity of one-tone DMRS while ensuring reliable phase tracking without requiring complex additional processing.
Data Source
AI summary
Methods, apparatuses, and computer program products for wireless communication are provided. A user equipment (UE) may be configured to determine a phase rotation for a symbol based at least in part on a tone index. The UE may be configured to apply the phase rotation to the received symbol, and transmit the uplink symbol. Numerous other aspects are provided.