UE Time Delay Reporting for Multi-TRP Pre-equalization
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Solution Overview
Problem
In wireless communication systems, particularly in 5G NR, there is a need to improve signal transmission efficiency across multiple transmission-reception points (TRPs) to ensure coherent summation of signals and reduce time dispersivity, as existing methods do not effectively account for time delays and phase differences between TRPs, leading to non-coherent signal summation and performance degradation.
Innovation Solution
User equipment (UE) reports time delays and phases of pilot signals received from multiple TRPs to the base station, allowing for pre-equalization of future transmissions to ensure that signals arrive at the UE with the same time delay and phase, thereby enabling coherent summation and improved receiver performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If signals are transmitted from multiple TRPs without pre-equalization, then transmission simplicity is maintained, but signal coherence deteriorates due to time delays and phase differences
Solution Approach 1:
The base station performs pre-equalization of signals before transmission from multiple TRPs by applying time delays and phase rotations based on channel state information. This preliminary adjustment ensures that signals arrive coherently at the UE, resolving the contradiction by preparing the signals in advance to achieve reliability without requiring complex real-time processing at transmission.
Solution Approach 2:
The system uses channel state information feedback from the UE to the base station to determine appropriate time delays and phase rotations for pre-equalization. This feedback mechanism enables the base station to adaptively adjust transmission parameters to maintain signal coherence across multiple TRPs, resolving the contradiction between reliability and complexity through informed decision-making.
2Reliability
If pre-equalization is applied to signals from multiple TRPs, then signal coherence is improved, but transmission processing complexity increases
Solution Approach 1:
The base station performs pre-equalization operations including time delay adjustment and phase rotation on signals before transmission from multiple TRPs. By applying these adjustments in advance based on channel state information, the system improves receiver performance while concentrating the processing complexity at the base station rather than requiring complex real-time coordination during transmission.
Solution Approach 2:
The system changes key signal parameters such as time delay and phase angle through pre-equalization to achieve coherent signal summation at the receiver. By adjusting these parameters beforehand based on channel conditions, the system improves reliability while managing complexity through parameter optimization rather than structural complexity.
3Reliability
If time delays between TRPs are not compensated, then transmission simplicity is maintained, but time dispersivity increases leading to performance degradation
Solution Approach 1:
The base station applies preliminary time delay compensation to signals from different TRPs based on channel state information before transmission. This ensures that signals arrive at the UE with aligned timing, reducing time dispersivity and improving communication performance without requiring complex real-time synchronization during signal reception.
Data Source
AI summary
Aspects of disclosure relate to a UE reporting to a gNB time delays and phases of pilot signals received via multiple transmission paths in order for the gNB to pre-equalize a future transmission to the UE. The UE determines a first time delay for receiving a first pilot signal from a gNB via a first path, determines a second time delay for receiving a second pilot signal from the gNB via a second path, and generates a report based on the first time delay and the second time delay. The UE then sends the report to the gNB and receives a multi-TRP signal from the gNB via the first path and the second path, wherein the multi-TRP signal is pre-equalized for transmission based on the report to at least have a same time delay as a shorter one of the first time delay or the second time delay.