Fully-diverse Sp(2) code design

A fully-diverse code that is suitable for differential modulation for four-transmit-antenna communication systems is constructed based on the symplectic group Sp(2). The code can be regarded as an extension of Alamouti’s celebrated two-transmit-antenna orthogonal design which can be constructed from the group Sp(1). The structure of the code lends itself to efficient ML decoding via the sphere decoding algorithm