Super-orthogonal double space–time trellis code

Abstract

This study develops a new class of super-orthogonal trellis codes for four transmit antennas based on double space–time codes. The transmit antennas are divided into two groups, each having two transmit antennas. The information bits are demultiplexed into two streams; each is encoded independently using a super-orthogonal trellis code and then is transmitted from the corresponding antenna group. The resultant parallel-trellis code structure offers a higher data rate and, at the same time, it has a smaller number of parallel branches in the trellis encoder compared to a single stream encoder. The decoding is done using the maximum likelihood (ML) decoder with an interference cancellation algorithm.It is shown that the proposed scheme reduces the required number of overall calculations by about half compared with super-orthogonal space–time trellis codes (SO-STTC) and super-orthogonal trellis coded spatial modulation (SOTC-SM).The performance of the designed codes is simulated and shows that an improvement in the frame error rate (FER) is achieved at 4 and 5 b/s.Hz compared with SO-STTC and SOTC-SM, while at 6 b/s.Hz, it achieved an improvement in the lower and medium range of signal-to-noise ratio (SNR) (<22 dB).