Non-coherent detection of MSK with transmit diversity in fast fading

We propose a minimum-shift keying (MSK) transmission scheme, motivated by the Alamouti-type block code structure. Taking advantage of the block-wise differential encoding on which the MSK transmission is based, the receiver is able to obtain non-coherent sequence estimates from a down-sampled subset of the received statistics. As a result of the sequence detection, the fast fading error floor associated with symbol-by-symbol differential detection is essentially eliminated. Furthermore, using the original received sequence and performing iterative channel estimation and sequence detection, the decisions are refined and further performance gains are observed. In fast fading, the results show that the proposed receiver performance is within 5 dB of the coherent detection lower bound, at a BER of 10^-3.