Robust channel estimation and interpolation

摘要

Present robust 2 Dimensional Minimum Mean Square Error (2D-MMSE) or minimax approach assumes significant time and frequency selectivity due to which it has a poor Mean Square Error (MSE) performance for Resource Blocks (RBs) with low/moderate frequency and/or time selectivity. A filter cannot be designed assuming low frequency and/or time selectivity and use that for all channel models. The instant invention proposes a Robust Adaptive (RA) MMSE filter that can bridge the gap between a robust 2D-MMSE/minimax and the optimal MMSE approach. The RA-MMSE filter smoothens the filter coefficients of the robust 2D-MMSE filter with the degree of smoothing adaptively changing with amount of frequency and time selectivity within a RB. The method uses multiple hypothesis tests on the maximum likelihood Channel Frequency Response (CFR) estimates at the pilots. The RA-MMSE filter solves the minimax estimation problem with additional constraints on the autocorrelation sequence corresponding to the channel frequency response.

主权项

1. A method for channel estimation for a received signal in an orthogonal frequency division multiplexing (OFDM) network, said method comprising of:
calculating a first channel frequency response estimate using said signal at pilot locations in said signal; grouping said first channel frequency estimates into a plurality of disjoint clusters; formulating at least one hypothesis test based on statistics which tests equality of mean between said clusters to check for similarity; dividing said first channel frequency estimates into said plurality of disjoint groups within each said clusters; checking for similarity of said groups within each of said clusters, when there is no similarity between any pair of said clusters; and estimating a final channel frequency response estimate, depending on level of similarity between said clusters.