Rotated Golden Codewords Based Space-Time Line Code Systems

Abstract

The space-time line code (STLC) has been recently proposed in the literature. In STLC systems, the channel state information is assumed to be known at the transmitter, but not at the receiver. In the conventional STLC systems, the inputs of the STLC encoder are either M-ary phase shift keying symbols or M-ary quadrature amplitude modulation symbols and can achieve diversity order with very low detection complexity. In order to further improve the error performance of the STLC systems, in this paper, rotated Golden codewords based STLC (RGC-STLC) systems are proposed.We extend the 1×2 and 2 × 2 transmit-receive antenna structure in the conventional STLC into 1 × 4 and 2 × 4 transmit-receive antenna structures in the proposed RGC-STLC system. The inputs of the proposed RGC-STLC encoder are the rotated Golden codewords. Compared to the conventional 1 × 2 and 2 × 2 STLC systems, the 1 × 4 and 2 × 4 RGC-STLC systems achieve a higher diversity order. Based on the feature of the rotated Golden codewords, low complexity detection schemes for the 1 × 4 and 2 × 4 RGC-STLC systems are further proposed. Finally, the union bounds on the average symbol error probability for the 1 × 4 and 2 × 4 RGC-STLC systems are derived and shown to match the simulation results very well at high signal-to-noise ratios.