Abstract
In this paper we exploit a quasi-orthogonal space time type block code with maximal distance property within a four relay network. This modified code is built from set partitioning a larger codebook formed from two quasi-orthogonal space time block codes with different signal rotations. In simulation studies the new code is shown to outperform previous open loop and closed loop schemes in terms of end-to-end error rate, and thereby has potential application in wireless relays networks.