Improved Detection of Differential Space-Time Block Codes

In this paper, the authors derive an improved sub-optimal differential detector for space-time block codes based on the maximum-likelihood detection when neither the transmitter nor the receiver has the knowledge of the channel. The proposed detection method is general enough to be applied to orthogonal space-time block codes, quasi-orthogonal space-time block codes and quasi-orthogonal space-time block codes with minimum decoding complexity. Compared with the existing sub-optimal schemes, the improved scheme can provide better error performance with acceptably increased decoding complexity. Simulation results show that the performance of the proposed detector is close to that of the maximum-likelihood detector without the knowledge of the received SNR. In addition, the performance improvement over the existing schemes becomes more significant as the transmission rate increases.