Li and Xia have recently investigated the design of space-time codes that achieve full spatial diversity for quasi-synchronous 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 this paper, we present a generalized stacking criterion for maximal rank-d binary codes and develop new explicit constructions. We also present several multilevel space-time code constructions for certain AM-PSK constellations that generalize the recent Lu-Kumar unified construction. Following the approach by Li and Xia, we show that, if the binary constituent codes used in these AM-PSK constructions are delay tolerant, so are the multilevel codes, making them well-suited for quasi-synchronous cooperative diversity applications.
展开▼