RedCap UE Positioning via Frequency Hopping and Bandwidth Stitching
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Solution Overview
Problem
Reduced Capability (RedCap) user equipments (UEs) face bandwidth limitations that lead to insufficient resolution in time domain, affecting the accuracy of DL-TDOA, UL-TDOA, and Multi-RTT timing-based positioning methods in wireless communication systems.
Innovation Solution
Implement frequency hopping with bandwidth stitching for DL-PRS and UL-SRS transmission, allowing coherent combining of channel observations across multiple frequency hops to improve positioning accuracy by configuring subbands or BWPs for RedCap UEs, and defining signaling mechanisms for DL-PRS and UL-SRS transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If frequency hopping with bandwidth stitching is implemented for DL-PRS and UL-SRS transmission, then positioning accuracy is improved, but device complexity increases
Solution Approach 1:
The patent divides the wide bandwidth positioning signal into multiple subbands that can be processed separately by RedCap UEs. Each subband is transmitted on a different frequency hop, allowing the UE to process narrower bandwidth segments sequentially rather than requiring simultaneous processing of the entire wide bandwidth, thus improving positioning accuracy without exceeding device complexity limits.
Solution Approach 2:
The patent implements dynamic frequency hopping where the frequency allocation for DL-PRS and UL-SRS changes across different time instances. This dynamic approach allows RedCap UEs to access wide bandwidth positioning signals by hopping between frequency subbands, effectively achieving high positioning accuracy while managing device complexity through time-division multiplexing of frequency resources.
2Measurement precision
If wide bandwidth positioning signals are transmitted, then positioning accuracy is improved, but sample time duration increases
Solution Approach 1:
The patent employs periodic frequency hopping for DL-PRS transmission, where the positioning reference signal is transmitted on different frequency subbands in a periodic manner. This allows RedCap UEs to accumulate positioning measurements across multiple periodic hops, achieving wide bandwidth positioning accuracy while maintaining efficient use of sample time through regular, predictable hopping patterns.
Solution Approach 2:
The patent ensures continuous positioning signal availability through overlapping frequency hops and configurable time gaps. By maintaining continuous transmission of positioning signals across frequency hops with minimal gaps, the system allows UEs to continuously accumulate measurement data, achieving high positioning accuracy without significant increases in total sample time duration.
3Measurement precision
If frequency hopping is configured for RedCap UEs, then positioning resolution is improved, but signaling overhead increases
Solution Approach 1:
The patent applies localized frequency hopping configurations specific to positioning purposes, rather than applying frequency hopping across all uplink and downlink signals. By configuring frequency hopping parameters (such as hop size, number of hops, and time gaps) specifically for DL-PRS and UL-SRS, the system improves positioning resolution while minimizing additional signaling overhead to only what is necessary for positioning functionality.
Data Source
AI summary
Various embodiments herein provide techniques for frequency hopping for positioning with reduced capability (RedCap) user equipments (UEs). For example, the RedCap UE may perform downlink positioning reference signal (DL-PRS) measurements using frequency hopping and bandwidth stitching. Additionally, or alternatively, the RedCap UE may transmit an uplink sounding reference signal (UL-SRS) using frequency hopping. Other embodiments may be described and claimed.