Serially concatenated space-time code using 2D interleaver

A new space-time code employing a serially concatenated code structure is proposed. The proposed structure has L independent layers, and the serially concatenated turbo encoding is performed in each layer. The key structure, a 2-dimensional (time and space) interleaver, is placed between the inner encoder and the outer encoder and reorders the encoded bits in time and space according to its interleaving pattern. By using the 2D interleaver, the temporal and spatial diversity gains are sufficiently achieved. Moreover, it reduces the correlations between the inputs and the outputs of the interleaver, so that it protects against error propagation from the inner decoder to the outer decoder. By adding the proposed scheme, the bit error performance is remarkably improved, while complexity increases only negligibly.