A new concatenated linear high rate space-time block code

Future wireless communication systems are characterized by heterogeneity in terms of node capabilities, link level requirements, propagation environments, cell designs and subnet structures. High carrier frequencies and large system bandwidth will make extreme diversity factors feasible. This imposes new requirements on space-time codes. In this paper we present a new concatenated linear space-time block coding scheme, which meets these requirements. The code consists of a linear time variant inner code and a linear time invariant outer code. We intentionally decouple the designs of each constituent code in order to achieve the required adaptivity. The inner code is optimized with respect to the variation of the instantaneous channel capacity over the block length of the outer code. Efficient inner coding matrices are given for pure TX diversity and joint spatial subchanneling and TX diversity. The linear outer code is optimized for diversity performance. We describe an efficient approach for the optimization of an unitary coding matrix for any given block length. Simulation results for different system parameters are presented. It is concluded that the proposed concatenated linear high rate space-time block coding scheme is a promising candidate for heterogeneous future mobile communication systems.