Pilot Design Strategies for Block Sparse Channel Estimation in OFDM Systems

Objectives: The objective functions for pilot design to minimize the inter-intra block coherence of sensing matrix. The efficient pilot design strategies was considered for the recovery of block sparse channel in pilot aided Orthogonal Frequency Division Multiplexing (OFDM) system using Compressive Sensing (CS) technique Methods: In particular, the pilot design directly influences the construction of sensing matrix in CS Frame work. This paper examines design measure of pilots based on minimizing a weighted sum of the inter and intra block coherence of the equivalent sensing matrix to improve block sparse channel estimation using block sparse CS algorithms. Findings: The multi carrier modulation, OFDM can achieve its benefits over multipath fading channel if Channel coefficients are perfectly estimated at the receiver. Block sparse with varying block size is prevalent in wideband frequency selective channel due to the presence of reflectors in the transmission. The explicit use of channel block sparsity and proper construction of sensing matrix for CS block sparse recovery algorithms yields better reconstruction performance. Applications: The proposed measure of pilot in sensing matrix design for varying block size of block sparse channel significantly outperforms the common inter block coherence along with CS based block sparse recovery algorithm.