  Typical receiver processing, targeting always the best achievable bit error
rate performance, can result in a waste of resources, especially, when the
transmission conditions are such that the best performance is orders of
magnitude better than the required. In this work, a processing framework is
proposed which allows adjusting the processing requirements to the transmission
conditions and the required bit error rate. It applies a-posteriori probability
receivers operating over multiple-input multiple-output channels. It is
demonstrated that significant complexity savings can be achieved both at the
soft, sphere-decoder based detector and the channel decoder with only minor
modifications.
