Improving the performance of coded FDFR multi‐antenna systems with turbo‐decoding

Abstract

AbstractA full‐diversity full‐rate (FDFR) multi‐antenna system was developed recently, enabling uncoded layered space‐time (LST) transmissions to achieve full‐diversity (Nt) and full‐rate (Nt symbols per channel use) simultaneously, for any number of transmit antennas Nt and receive antennas Nr. In this paper, we investigate the performance of a coded FDFR design obtained by concatenating an error control coding (ECC) module and FDFR module with a random interleaver in between. Turbo decoding is performed at the receiver. With Rc denoting the ECC rate, dmin the minimum Hamming distance of the ECC, and M the constellation size, an overall transfer rate of RcNtlog2M bits per channel use and a full diversity order dminNtNr are achieved. Different ECC choices are considered. Approximate analysis reveals that multi‐stream ECC and single‐stream ECC make no difference when convolutional codes with long frame length and near‐optimal MIMO decoding schemes are adopted. Without sacrificing rate, the coded FDFR system improves error performance compared with coded V‐BLAST, when relatively weak codes are used. As Nr increases, even strong codes such as rate 1/2 turbo codes can benefit from FDFR. Specifically, 1.5–2 dB gain over coded V‐BLAST is obtained in a 2 × 2 antenna setup when convolutional codes or rate 3/4 turbo codes are used; 0.5 dB gain is offered in a 2 × 5 setup when rate 1/2 turbo codes are used. Coded FDFR also outperforms a 16‐QAM Alamouti coded scheme by 1 dB when convolutional codes are used. The price paid is increased complexity. Copyright © 2004 John Wiley & Sons, Ltd.