Channel Response Estimation Using Cross-Correlation Filtering
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Solution Overview
Problem
Existing methods for channel response estimation in OFDM systems, such as Least Squares and MMSE algorithms, are inadequate for accurately determining channel response information for updated subframes due to differences in cross-correlation matrices across carriers, leading to deteriorated performance.
Innovation Solution
A method involving conjugate multiplication of channel estimations to obtain cross-correlation matrices, followed by filtering and linear prediction using these matrices to accurately acquire channel response information for updated subframes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If cross-correlation matrix of entire bandwidth is used to obtain channel response of updated subframe, then channel response can be obtained, but channel response estimation performance deteriorates due to differences in cross-correlation matrices of individual carriers
Solution Approach 1:
The patent divides the entire bandwidth into multiple individual carrier cross-correlation matrices. Instead of using a single cross-correlation matrix for the entire bandwidth, the method segments the processing into carrier-specific matrices, allowing each carrier to be estimated independently with its own characteristics, thereby improving estimation accuracy.
Solution Approach 2:
The patent applies local quality by using carrier-specific cross-correlation matrices tailored to each individual carrier's characteristics. Each carrier gets its own optimized estimation approach rather than a one-size-fits-all method, allowing the system to adapt to local variations in channel conditions across different carriers.
2Loss of time
If historical subframe channel estimation methods are used, then estimation can be performed, but only historical subframe channel response can be obtained, not updated subframe response
Solution Approach 1:
The patent uses preliminary action by performing linear prediction based on historical channel estimates to proactively obtain the channel response of the updated subframe before actual transmission. This allows the system to prepare channel state information in advance, reducing latency while maintaining accuracy through the prediction mechanism.
Solution Approach 2:
The patent implements feedback by using historical channel estimation results as input for predicting current channel conditions. The system continuously updates channel response estimates by feeding back previous estimation data through the linear prediction process, enabling adaptive tracking of channel variations over time.
Data Source
Figure 1~3
AI summary
A method and device for acquiring channel response. The method comprises: acquiring channel estimations of all carriers from a (n-m)th frame to a (n-1)th frame by means of a sounding reference signal (SRS); carrying out conjugate multiplication on the channel estimations to obtain a cross correlation matrix of all the carriers from the (n-m)th frame to the (n-1)th frame, and estimating cross correlation matrixes between a subframe p of an nth frame and all the carriers from the (n-m)th frame to the (n-1)th frame; filtering all elements Rpq of the cross correlation matrixes of all the carriers; and acquiring channel responses H(n) of all carriers of the subframe p of the nth frame by means of a linear prediction algorithm by utilizing the cross correlation matrixes, n, m and p all being positive integers.