1. A low complexity Minimum Mean Square Error (MMSE) based sequential Monte Carlo method for Multiple-Input Multiple-Output (MIMO) demodulation, said method comprising the steps of: receiving a plurality of signals at an array of receive antennas; estimating a channel matrix; determining a channel dependent order of demodulation that is responsive to the estimated channel matrix; processing the received signal vector through the use of MMSE techniques; modeling the processed received signal vector as being equal to the sum of a linear transformation of the transmitted symbols by a triangular matrix having positive diagonal elements and a vector representing a realization of a plurality of un-correlated Gaussian random variables; and demodulating the said transmitted symbols using deterministic sequential Monte Carlo techniques on the processed received signal and the said model.