Precoded Phase Synchronization Reference Signal for CoMP
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Solution Overview
Problem
In wireless communication networks, especially in CoMP joint transmission operations, phase synchronization across multiple base stations is challenging due to phase drifts caused by clock jitter and electronic component dynamics, leading to degraded performance.
Innovation Solution
A method where a base station estimates an uplink channel estimate based on a sounding reference signal from a UE, transmits a phase synchronization reference signal modulated with this estimate, receives phase compensation information from the UE, and adjusts transmission characteristics to compensate for phase and timing drifts, while the UE measures and reports phase drifts to base stations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If phase synchronization reference signals are transmitted without pre-coding, then the system complexity is reduced, but phase synchronization accuracy deteriorates due to phase drifts from clock jitter and electronic component dynamics
Solution Approach 1:
The base station pre-estimates uplink channel characteristics using sounding reference signals (SRS) transmitted by the UE before the actual phase synchronization procedure. This preliminary channel estimation enables the base station to pre-code the phase synchronization reference signals with appropriate phase compensation, thereby proactively counteracting phase drifts caused by clock jitter and electronic component dynamics before they degrade synchronization accuracy
Solution Approach 2:
The system implements a feedback mechanism where the UE measures the phase synchronization reference signals and reports phase difference information back to the base station. The base station uses this feedback to continuously update and refine its channel estimates and phase compensation parameters, creating a closed-loop system that adapts to changing phase conditions and maintains synchronization accuracy over time
2Measurement precision
If phase compensation procedures are implemented frequently, then phase synchronization accuracy is improved, but signaling overhead and processing time increase
Solution Approach 1:
The system implements periodic phase synchronization procedures where the base station transmits phase synchronization reference signals at regular intervals rather than continuously. The frequency of these periodic transmissions is optimized to maintain phase synchronization accuracy within acceptable thresholds while minimizing unnecessary signaling overhead and processing time. The periodicity is adjusted based on observed phase drift rates and service requirements
Solution Approach 2:
The system dynamically adjusts the timing and frequency of phase compensation procedures based on changing channel conditions, UE mobility, and service requirements. When phase drift is detected to be within acceptable ranges, the system reduces the frequency of compensation procedures to save time and resources. When phase drift exceeds thresholds, the system increases compensation frequency to maintain accuracy, thereby adaptively optimizing the trade-off between synchronization accuracy and processing time
Data Source
AI summary
Phase compensation in a new radio (NR) coordinated multipoint (CoMP) environment is discussed. A base station may synchronize the phase between one or more additional base stations in a CoMP group serving one or more user equipments (UEs). A base station estimates an uplink channel based on a sounding reference signal (SRS) received from a given UE. The base station transmits a phase synchronization reference signal (PSRS) modulated using the uplink channel estimate. The UE can measure the phase and/or timing drift from the PSRS and then will report the compensation information for the phase and timing drift back to the base station. The base station may then use the compensation information to adjust transmission characteristics for the CoMP group.