Space-frequency transmission and channel estimation for 2×2 cooperative systems

In this paper, we propose a distributed space-frequency transmit scheme in double selective channels for the OFDM cooperative system with two source and two destination nodes. In stead of interfering with each other, the two links cooperate by letting a source be a relay of the other one. Under this structure, the two sources can fulfill cooperative transmission together. We also design the frame structure to estimate the double selective channels. With the proper transmit and receive processing, the performance of this scheme can approach that of the 2 × 1 space-frequency block code.