Improved space-time codes using serial concatenation

In this letter, a new family of space-time codes is proposed. These codes employ a serially concatenated coding scheme with a standard space-time code as the outer code and a very simple rate-1 recursive code as the inner code. Adding this simple rate-1 recursive inner code does not decrease the bit rate and introduces only negligible complexity increase to the transmitter when compared to cases with standard space-time codes. An interleaver is embedded between the inner coder and the outer coder and the size of this interleaver determines the performance gain. We also provide a relatively low complexity iterative decoding procedure. For applications which can tolerate delay, significant gain can be achieved with the proposed approach.