Dynamic Reference Signal Configuration for Sidelink and Downlink
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently reporting and configuring sidelink and downlink reference signals, leading to suboptimal channel estimation and performance in terms of reliability and latency.
Innovation Solution
A method and apparatus for a communication device to receive transmissions over a shared channel, determine parameters like Doppler spread or delay spread, select a suitable reference signal configuration, and transmit feedback to adjust the reference signal configuration for subsequent transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If reference signal configurations are fixed and not dynamically adjusted, then device complexity is reduced, but channel estimation accuracy and communication reliability deteriorate
Solution Approach 1:
The patent implements dynamic reference signal configuration where the receiving device determines channel parameters (Doppler spread, delay spread) from received transmissions and selects appropriate reference signal configurations based on these parameters. This dynamic adaptation allows the system to adjust reference signal density and patterns according to actual channel conditions, improving reliability without requiring overly complex fixed configurations.
Solution Approach 2:
The receiving device provides feedback to the transmitting device about the selected reference signal configuration based on measured channel parameters. This feedback loop enables the transmitting device to adjust future reference signal transmissions appropriately, improving channel estimation accuracy and communication reliability while maintaining manageable device complexity through standardized feedback mechanisms.
2Measurement precision
If reference signal density is increased to improve channel estimation, then channel estimation accuracy improves, but throughput and latency worsen due to increased overhead
Solution Approach 1:
The patent changes the density and pattern parameters of reference signals dynamically based on measured channel conditions. When channel conditions are stable (low Doppler spread, low delay spread), the system reduces reference signal density to improve throughput. When channel conditions are harsh or changing rapidly, the system increases reference signal density to maintain channel estimation accuracy, thus optimizing the trade-off between measurement precision and productivity.
3Measurement precision
If reference signal configuration is adapted to channel conditions, then channel estimation accuracy improves, but processing time and latency increase
Solution Approach 1:
The receiving device performs channel parameter measurement and reference signal configuration selection in advance before actual data transmission. By determining Doppler spread and delay spread from received transmissions and pre-selecting the appropriate reference signal configuration, the system minimizes processing time during actual communication, reducing latency while maintaining high channel estimation accuracy.
4Adaptability or versatility
If multiple reference signal configurations are maintained for different channel conditions, then adaptability improves, but device complexity and memory requirements increase
Solution Approach 1:
The patent segments the channel conditions into distinct categories based on channel parameters (e.g., high/low Doppler spread, high/low delay spread) and assigns specific reference signal configurations to each segment. This segmentation approach allows the device to maintain a manageable set of predefined configurations while achieving good adaptability to different channel conditions, avoiding the need to store and process an excessive number of configurations.
Data Source
AI summary
A communication device receives, from another communication device, a set of transmissions over a sidelink shared channel, or over a downlink shared channel (1005). The communication device estimates a Doppler spread or a delay spread based on the received set of transmissions over the shared channel (1010). The communication device selects a reference signal configuration, from multiple reference signal configurations, based on the estimated Doppler spread or the estimated delay spread (1015). The reference signal is a DMRS, a PTRS and/or a TRS. Finally, the communication device transmits feedback indicating the selected reference signal configuration for a subsequent set of transmissions over the shared channel (1020).