1. A receiver to receive a communication signal sent through a communication channel, the receiver comprising a Soft Input Soft Output receiver that, in use, is operable to receive the communication signal and a priori information about the communication signal and to use the a priori information to estimate the interference in the communication signal, the estimation based on candidate vectors having K samples iteratively drawn using Gibbs sampling, wherein, if a drawn kth sample of a candidate vector has not changed value for a predetermined number of candidate vectors, then the Soft Input Soft Output receiver operates to change the value of the drawn kth sample.