Modified OMP Algorithm for Compressible Channel Impulse Response Estimation

Wireless communication link at the physical layer can be described as a signal transmission over multiple propagation paths which are different in the gain and the delay. But in reality there are only a few significant paths responsible for the most signal energy transmission between transmitter and receiver. Such a sparse nature of the propagation environment promotes the use of the compressed sensing methods for channel impulse response estimation in the receiver. Unfortunately, a typical band-limited transmission violates the strict channel sparsity making the impulse response reconstruction more complex. The paper presents an analysis of channel impulse response estimation with the Orthogonal Matching Pursuit algorithm. A modification of the classical OMP method is proposed in order to improve both the channel estimation and the data transmission qualities in case of a weak condition of the impulse response sparsity. This proposition is numerically evaluated for the general case of the OFDM transmission over a sixth path urban channel model. The results are compared to the ones obtained for the strict sparse impulse response instance.