On lattice decoding of space-time block codes for asynchronous cooperative relaying

Li and Xia have recently investigated the design of space-time codes that achieve full spatial diversity for asynchronous cooperative communications. They show that certain of the binary space-time trellis codes derived from the Hammons-El Gamal stacking construction are delay tolerant and can be used in the multilevel code constructions by Lu and Kumar to produce delay tolerant space-time codes for PSK and QAM signaling. In prior work, the first author has developed generalizations of the Lu-Kumar construction for more general AM-PSK constellations that also preserve the delay tolerance of the underlying constituent codes and exhibited a new construction of short block codes that achieve significant levels of delay tolerance. This paper discusses how lattice decoding techniques can be adapted to perform decoding of such STBC for asynchronous diversity.