We have investigated the performance of the sphere decoding algorithm.

As it has shown in the computer simulations, the decoder based on the

sphere decoding algorithm has almost the same performance of a maximum

likelihood decoder with much lower complexity. Further simulations of the

sphere decoding algorithms has shown, with the channel estimation error

at the receiver, the decoder with the sphere decoding algorithm still has

the same performance as in a ML decoder without increase the decoding

complexity.