Serially concatenated space-time code using 2-D 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, 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 2-D interleaver, the temporal and the spatial diversity gains are sufficiently achieved. Moreover, it reduces the correlations between the inputs and the outputs of the interleaver, so that it protects the error propagation from the inner decoder to the outer decoder. By adding the proposed scheme, the bit error performance is remarkably improved, while only negligible complexity increases.