Narrowband Signal Phase Alignment for 5G Positioning
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Solution Overview
Problem
Current positioning techniques in 5G NR networks face challenges in achieving accurate positioning for devices with reduced capabilities, such as those with narrowband RF analogue fronts, as they cannot coherently combine narrowband signals due to random phase offsets, leading to inferior positioning accuracy compared to wideband signals.
Innovation Solution
The method involves configuring the reception of multiple narrowband signals with specific time-frequency resources based on channel coherence estimates, determining and compensating for phase offsets between these signals, and then combining them to form a composite wideband signal for improved positioning accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If narrowband signals are received and combined without phase compensation, then device complexity is reduced, but positioning accuracy deteriorates due to random phase offsets
Solution Approach 1:
The patent applies preliminary action by estimating channel coherence time and bandwidth before receiving narrowband signals, and by determining phase offsets between signals before combining them. This pre-processing enables coherent combination of narrowband signals to achieve wideband positioning accuracy without requiring complex wideband hardware, thus resolving the contradiction between device complexity and positioning accuracy
Solution Approach 2:
The patent changes the parameter of signal bandwidth by receiving multiple narrowband signals at different frequency resources and combining them to form a composite wideband signal. By adjusting the frequency spacing of received signals to be within the estimated channel coherence bandwidth, the system achieves wideband positioning performance using narrowband receivers, resolving the contradiction between receiver capabilities and positioning accuracy
2Measurement precision
If multiple narrowband signals are received at different frequency resources, then positioning resolution is improved, but phase offset compensation complexity increases
Solution Approach 1:
The patent replaces complex hardware-based wideband reception with a software-based approach of receiving multiple narrowband signals and combining them through digital signal processing. By substituting physical wideband RF chains with multiple narrowband receivers plus phase compensation algorithms, the system achieves wideband positioning resolution while maintaining simpler receiver hardware, thus resolving the contradiction between positioning resolution and processing complexity
3Device complexity
If narrowband signals are combined without considering channel coherence, then device complexity is reduced, but positioning accuracy deteriorates due to temporal and spectral decorrelation
Solution Approach 1:
The patent applies preliminary action by estimating channel coherence time and bandwidth before configuring the reception of narrowband signals. This pre-estimation enables proper configuration of time-frequency resources for signal reception, ensuring that combined signals remain within coherence boundaries and maintain correlation, thus resolving the contradiction between configuration simplicity and positioning accuracy
Data Source
AI summary
Certain examples relate to an apparatus for receiving configuration information to receive a first Reference Signal (RS), and a second RS, wherein the configuration information comprises information indicative of: a first and second time-frequency resource allocated to the first and second RS respectively; wherein the allocation of at least one of the resources is based, at least in part, on: an estimate of a coherence time and a coherence bandwidth of a channel between the apparatus and a node; receiving, based at least in part on the configuration information, the first and second RSs; determining a phase offset between the received first and RSs; adjusting the first or second received RS based, at least in part, on the phase offset; and generating, based, at least in part, on the adjusted RS and the other of the first and second RS, a third RS for use in position estimation.