Pilot Design for Sparse Channel Estimation in Large-Scale MIMO-OFDM System

Algorithm 1

Alternating projection algorithm.

Input:

 (i) An arbitrary initial matrix and the number of iterations

Output:

 (i) A pair of matrices (, )

Procedure:

 (1) Initialize .

 (2) Find which satisfies Property (i) and is nearest to in Frobenius norm.

 (3) Find which satisfies Property (ii) and is nearest to in Frobenius norm.

 (4) Increment .

 (5) Repeat step (2) to step (4) until .