Differential detection based on space-time block codes

In this paper we consider the use of differential detection when there are multiple transmitter and receiver antennas. Our differential scheme is based on the theory of Space-Time Block Codes that are used to achieve space-time diversity. Compared to the existing differential schemes for multiple antennas our scheme has a much smaller computational complexity. It has the same encoding and decoding complexities as the coherent detection based on space-time block codes and achieves the same rate for up-to 8 transmitter antennas. The performance of the differential detector (which assumes no knowledge of the flat fading channel) is 3 dB less than that of the coherent detector (which uses exact channel state information for reception). We also show that the proposed receiver is a Maximum Likelihood detector.