Differential Distributed Space-Frequency Coding for Broadband Non-Regenerative Wireless Relaying Systems

Exploiting the desirable properties of cyclic group coding, we develop a full-rate differential distributed space- frequency coding (DSFC) in the frequency domain for broadband non-regenerative wireless relaying systems. The pairwise error probability analysis demonstrates that our scheme guarantees a diversity order of G_d les min{ML₁, ML₂}, where M is the number of the relay nodes, and L₁ and L2 are the number of taps of source-to-relay and relay-to-destination channels, respectively. A novel subcarrier allocation method without channel state information (CSI) at any node is proposed to improve the diversity product. Moreover, for an arbitrary number of relays, a competitive non-regenerative DSFC proposed by Zhang et. aL, is extended to differential transmission incorporated with the proposed subcarrier allocation method for fair comparison. Both theoretical analysis and simulation results confirm that the proposed DSFC outperforms Zhang´s scheme significantly in the differential case.