Blind detection of OFDM signals in fading channels

In this paper, we apply branch and bound principle to solve the equivalent nonlinear integer programming problem. A recursive formula for fast metric update is obtained by exploiting the intrinsic characteristics of our objective function. The impacts of reordering the data sequence and selective detection are addressed. By suggesting a preferred order and selective detection method, we greatly reduce the detector complexity while giving up little performance loss. We also extend our investigation to the semiblind case where only sparse pilot symbols are available.