Robust PUSCH Codebook Selection for Phase-Coherent 5G Uplink
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Solution Overview
Problem
In 5G wireless communication systems, phase noise and common phase errors (CPEs) between transmission antenna ports due to different oscillators or large distances lead to difficulties in coherent transmission, especially in mmWave bands, which are not effectively addressed by existing codebook-based transmission methods.
Innovation Solution
A robust codebook design is proposed, incorporating phase tracking reference signals (PT-RS) and different waveforms, allowing for dynamic selection of precoders and waveforms based on UE capabilities, using a two-stage codebook approach to facilitate coherent transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If codebook-based transmission is used in 5G systems, then transmission capacity and connectivity are improved, but phase noise and common phase errors between antenna ports worsen coherent transmission performance
Solution Approach 1:
The codebook is divided into multiple codebook subsets, each optimized for specific phase noise conditions. The system segments the overall codebook space to allow selective use of subsets that are robust against phase noise and CPEs, thereby maintaining coherent transmission performance while preserving transmission capacity.
Solution Approach 2:
The patent introduces phase tracking reference signals (PT-RS) and modifies the codebook structure to incorporate parameters that track and compensate for phase noise. By changing the codebook parameters and introducing PT-RS, the system adapts to phase variations and maintains reliable coherent transmission.
2Adaptability or versatility
If different oscillators are used in transmission antenna ports, then transmission flexibility is improved, but phase synchronization between ports deteriorates
Solution Approach 1:
Phase tracking reference signals (PT-RS) are introduced to provide feedback mechanisms for monitoring phase variations between antenna ports. The system uses these reference signals to detect phase drift caused by different oscillators and applies compensation to maintain phase synchronization, thereby preserving both flexibility and stability.
Solution Approach 2:
The codebook design incorporates preliminary phase compensation measures by pre-defining codebook subsets that account for expected phase variations. This preliminary action allows the system to pre-adapt to oscillator-induced phase differences, maintaining synchronization without real-time intervention.
3Reliability
If PT-RS and waveform selection are incorporated into codebook design, then coherent transmission is improved, but system complexity increases
Solution Approach 1:
The codebook is designed to serve multiple functions: it provides both data transmission and phase tracking capabilities through integrated PT-RS. The same codebook structure supports different waveforms and phase compensation mechanisms, reducing the need for separate systems and thereby managing complexity while improving coherent transmission.
Data Source
AI summary
The present disclosure provides apparatuses, systems, methods, and machine readable storage medium for physical uplink shared channel (PUSCH) transmission between a user equipment (UE) and a base station, based on a robust codebook. In an embodiment, a UE, including circuitry operable to: report a UE capability of the UE to a base station, wherein the UE capability comprises a number of phase tracking reference signal (PT-RS) antenna ports (NPT-RS) supported by the UE; decode control signaling received from the base station, wherein the control signaling comprises at least one parameter to indicate a precoder selected from a codebook based on at least the NPT-RS; and perform physical uplink shared channel (PUSCH) transmission according to the indicated precoder; wherein the codebook is predefined or configured based on different numbers of PT-RS antenna ports and different waveforms, in the UE and the base station.