“…By employing the CS theory and exploiting the sparsity of the channel, it is expected that the number of pilot symbols can be reduced [1,3,4,13,15,17,18]. In [1,3,4,13,17,18], the CS theory has been employed for sparse channel estimation in multicarrier systems. In particular, the pilot symbols are placed randomly [1,17,18] or evenly [3,4].…”