Wireless Channel SNR Estimation with Two-Step OCC Timing Compensation
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Solution Overview
Problem
Existing wireless communication systems experience SNR saturation at higher operating signal levels due to erroneous least squares channel estimates resulting from OCC removal before timing offset compensation, leading to underrating the user equipment's capability for advanced scheduling configurations.
Innovation Solution
A two-step OCC removal and timing compensation process is applied to the least squares channel estimate, involving the removal of a first OCC sequence, determining an estimated timing offset, adjusting the timing, removing a second OCC sequence, and calculating a robust SNR based on noise and signal powers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If OCC removal is performed before timing offset compensation, then the processing sequence is simplified, but erroneous least squares channel estimates result causing SNR saturation
Solution Approach 1:
The patent applies preliminary timing offset compensation to the received signal before performing OCC removal and channel estimation. This preliminary action corrects timing misalignment at the earliest stage, preventing the propagation of timing errors through subsequent processing steps, thereby avoiding SNR saturation while maintaining a clear processing sequence
Solution Approach 2:
The patent inverts the conventional processing order by performing timing offset compensation before OCC removal, rather than removing OCC first. This inversion of the processing sequence eliminates the root cause of erroneous channel estimates and SNR saturation, while the patent structures the method to present this inverted sequence in a systematic and easy-to-follow manner
2Device complexity
If single-step OCC removal is used, then the processing complexity is reduced, but SNR saturation occurs at higher operating SNRs
Solution Approach 1:
The patent segments the SNR estimation process into distinct stages: timing offset compensation, first OCC removal, channel estimation, second OCC removal, and final SNR calculation. This segmentation allows each stage to be optimized independently, achieving both reduced complexity and improved reliability through systematic multi-step processing
Solution Approach 2:
The patent applies preliminary timing offset compensation and first OCC removal before channel estimation to ensure accurate channel parameters are obtained. This preliminary processing prevents timing and orthogonality errors from contaminating the channel estimates, thereby avoiding SNR saturation while maintaining manageable processing complexity
3Speed
If timing offset compensation is delayed until after OCC removal, then the initial processing is faster, but channel estimation accuracy deteriorates
Solution Approach 1:
The patent performs timing offset compensation as a preliminary step before OCC removal and channel estimation. This preliminary timing correction ensures that all subsequent processing operations are performed on properly aligned signals, maintaining high channel estimation accuracy without significantly impacting overall processing speed due to the efficient implementation of the compensation algorithm
Data Source
AI summary
A method includes determining a least squares channel estimate (LSE) of a channel, removing a first Orthogonal cover code (OCC) sequence from the LSE thereby generating a first signal, determining an estimated timing offset of the first signal, adjusting a first timing of the LSE based on the estimated timing offset thereby generating a second signal with an adjusted timing, removing a second OCC sequence from the second signal thereby generating a third signal, determining a channel estimate of the channel based on the third signal, determining a noise power of a received signal, determining a signal power of the received signal, determining a signal to noise ratio (SNR) of the received signal based on the noise power and the signal power, adjusting a data rate of the channel based on the SNR, and transmitting an output signal based on an adjusted data rate of the channel.