Segmented TRS Patterns for High-Speed Doppler Tracking
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Solution Overview
Problem
Wireless communications systems face challenges in maintaining reliable time and frequency tracking for user equipment (UE) in high-speed scenarios due to maximum doppler shift exceeding the pull-in range for carrier frequency offset estimation, leading to unreliable acquisition of tracking reference signals (TRS).
Innovation Solution
Implementing an enhanced TRS pattern with reduced symbol intervals between TRS transmissions, allowing for additional TRSs within a given time period, which doubles the pull-in range and ensures reliable time and frequency tracking for UEs in high-speed scenarios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional TRS patterns with larger symbol intervals are used, then device complexity and power consumption are reduced, but the pull-in range is insufficient for high-speed scenarios with large doppler shift
Solution Approach 1:
The TRS pattern is segmented into multiple portions (first portion and second portion) with different symbol intervals. The first portion uses a larger symbol interval for normal operation, while the second portion uses a smaller symbol interval to extend the pull-in range for high-speed scenarios. This segmentation allows the system to adapt to different mobility conditions without always using the more complex pattern.
Solution Approach 2:
The TRS pattern dynamically adjusts its configuration based on UE mobility conditions. The network can configure different TRS patterns (with different symbol intervals) depending on whether the UE is in high-speed or normal-speed scenario, allowing the system to optimize between pull-in range and resource efficiency dynamically.
2Reliability
If TRS transmissions are spaced further apart in time, then resource efficiency improves, but the pull-in range for carrier frequency offset estimation decreases
Solution Approach 1:
The TRS pattern is divided into multiple portions with different time spacing. The first portion has larger symbol intervals that consume fewer time resources, while the second portion has smaller symbol intervals that provide extended pull-in range. This segmentation allows the system to allocate time resources efficiently while maintaining estimation accuracy when needed.
Solution Approach 2:
The symbol interval parameter of the TRS pattern is changed based on mobility conditions. For normal-speed UEs, a larger symbol interval is used to save time resources. For high-speed UEs, the symbol interval is reduced to extend the pull-in range, ensuring accurate carrier frequency offset estimation despite the increased time resource consumption.
Data Source
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AI summary
Methods, systems, and devices for wireless communications are described. A user equipment (UE) may transmit, to a base station, a UE capability to receive a first portion of a tracking reference signal (TRS) and a second portion of the TRS, the first portion and the second portion associated with a TRS pattern. The EE may receive, from the base station, an indication of the TRS pattern, where the TRS pattern includes the first portion of the TRS pattern and the second portion of the TRS pattern. The EE may receive one or more TRSs according to the first portion of the TRS pattern and the second portion of the TRS pattern.