Non-Contiguous Spectrum TOA Estimation with Full-Band CFR Mapping
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Solution Overview
Problem
Existing time of arrival (TOA) estimation technologies in cellular positioning are limited by the bandwidth of reference signals, particularly in non-contiguous spectrum scenarios, leading to suboptimal estimation accuracy and spectral inefficiency.
Innovation Solution
A method that reconstructs the phase relationship of channel frequency responses across non-contiguous frequency bands by determining and mapping channel frequency responses (CFRs) to a full bandwidth, enabling coherent TOA estimation and achieving a cross-frequency gain, while reducing frequency selective channel characteristics and sidelobe interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If non-contiguous spectrum transmission is used to break bandwidth limitation, then frequency domain resources occupied by signal are reduced, but TOA estimation accuracy deteriorates due to frequency selective channel characteristics and sidelobe interference
Solution Approach 1:
The patent introduces a virtual full-bandwidth CFR as an intermediary representation that bridges the gap between non-contiguous frequency bands. By constructing a virtual CFR that spans the entire frequency range (including gap bands) and applying phase compensation, the system enables coherent integration of TOA estimates across non-contiguous bands, thereby maintaining measurement precision while utilizing fragmented spectrum resources
Solution Approach 2:
The patent changes the phase parameter of CFR values across different frequency bands by applying phase compensation. This parameter transformation aligns the phases of CFRs from non-contiguous bands, enabling constructive interference and coherent integration in the time domain, which resolves the sidelobe interference issue and improves TOA estimation accuracy
2Ease of operation
If single-carrier maximum bandwidth is used in FR1, then TOA estimation is straightforward, but TOA estimation accuracy is limited by the 100 MHz bandwidth constraint
Solution Approach 1:
The patent segments the available spectrum into multiple non-contiguous frequency bands and processes each band separately to obtain individual CFRs. These segmented CFRs are then combined through phase compensation and coherent integration to achieve an effective bandwidth greater than any single carrier, thereby improving measurement precision while maintaining operational simplicity through standardized processing steps
Solution Approach 2:
The patent merges multiple CFRs from non-contiguous frequency bands into a single virtual full-bandwidth CFR by applying phase compensation and coherent integration. This combining process effectively synthesizes a wider bandwidth signal, improving TOA estimation accuracy while preserving the simplicity of single-carrier processing methodologies
Data Source
AI summary
A method for estimating a time of arrival based on non-contiguous spectrums includes receiving a plurality of signals from a transmit end on a plurality of frequency bands. The plurality of frequency bands are in a one-to-one correspondence with the plurality of signals. The method also includes determining, based on the plurality of signals, channel frequency responses (CFRs) of the frequency bands corresponding to the plurality of signals. The method further includes determining a CFR of a full bandwidth based on the CFRs of the frequency bands corresponding to the plurality of signals. The method additionally includes determining a time of arrival estimate based on the CFR of the full bandwidth. The time of arrival estimate is used to determine location information of a terminal device.