Tx Pre-Equalization Refresh for Wireless Channel Aging Mitigation
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Solution Overview
Problem
In wireless communication systems, particularly for extended reality (XR) applications, channel aging due to synchronization errors and mobility causes performance degradation, especially in pre-equalized transmissions, limiting battery life and latency in devices with reduced processing capabilities.
Innovation Solution
Implementing a Tx pre-equalization scheme on a companion device to offload receiver complexity from the XR device, and periodically refreshing the pre-equalization matrix to mitigate channel aging by allocating pre-equalized DMRS for a subset of slots, allowing fallback to Rx equalization if needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If Tx pre-equalization is applied to offload receiver complexity, then processing complexity and power consumption on the XR device are reduced, but channel aging due to synchronization errors and mobility causes performance degradation
Solution Approach 1:
The patent applies preliminary action by performing channel estimation and equalization matrix computation in advance at the companion device before data transmission. The companion device estimates the channel response and computes the equalization matrix beforehand, then transmits this pre-computed information to the XR device. This allows the XR device to simply apply the pre-computed equalization without performing complex real-time channel estimation, thereby reducing receiver complexity while maintaining reliability through advance preparation.
2Reliability
If pre-equalization matrix is refreshed periodically, then channel aging is mitigated, but latency increases due to the periodic refresh requirement
Solution Approach 1:
The patent implements periodic action by establishing a periodic refresh mechanism for the pre-equalization matrix. The companion device periodically re-estimates the channel response and re-computes the equalization matrix at predetermined intervals. This periodic refresh ensures that the equalization remains effective despite channel changes over time, mitigating channel aging effects. The periodic nature allows for predictable timing and can be optimized to balance between maintaining accuracy and minimizing latency.
3Measurement precision
If pre-equalized DMRS is allocated for all slots, then channel estimation is comprehensive, but processing overhead and resource consumption increase
Solution Approach 1:
The patent applies local quality by selectively allocating pre-equalized DMRS only to specific slots rather than uniformly across all slots. The companion device determines which slots require DMRS allocation based on local channel conditions, mobility patterns, and synchronization status. This selective approach ensures that channel estimation is performed only where necessary, maintaining measurement precision for critical slots while reducing processing overhead and resource consumption in slots where the pre-equalization remains valid without requiring refresh.
Data Source
AI summary
An apparatus may be a wireless device such as a user equipment (UE) configured to receive, from a wireless device associated with the UE, a first indication of a capability to perform an equalization operation and transmit, to the wireless device, a second indication of an allocation of resources associated with a pre-equalized demodulation reference signal (DMRS) for the equalization operation, wherein the allocation of resources is for less than all slots within a set of slots associated with a same pre-equalization.