Sampling of Sparse Channels with Common Support

The present paper proposes and studies an algorithm to estimate channels with a sparse common support (SCS). It is a generalization of the classical sampling of signals with Finite Rate of Innovation (FRI) [1] and thus called SCS-FRI. It is applicable to OFDM and WalshHadamard coded (CDMA downlink) communications since SCS-FRI is shown to work not only on contiguous DFT pilots but also uniformly scattered ones. The support estimation performances compare favorably to theoretical lower-bounds, and importantly this translates into a substantial equalization gain at the receiver compared to the widely used spectrum lowpass interpolation method. Keywords— Channel estimation, MIMO, OFDM, CDMA, Finite Rate of Innovation