Abstract: Received symbols are decoded in a multiple-antenna communication system using lattice-based decoding. The symbols are generated using a modulation constellation, e.g., a diagonal modulation constellation, and the constellation is characterized as a lattice for decoding purposes. For example, if a given communication link of the multiple-antenna communication system includes M transmitter antennas and a single receiver antenna, the diagonal modulation constellation can be characterized as a lattice in M dimensions. A differential decoding operation for received differential symbols involves a determination of the closest point in the lattice corresponding to the constellation. This determination may be made in an efficient manner using a basis reduction algorithm which generates an approximately orthogonal basis for the lattice, and then utilizes component-wise rounding to determine the closest point.