Multistage symbol-by-symbol Bayesian interference cancellation for UMTS-CDMA links affected by severe multipath

A simple multiuser detector (MUD) is proposed for UMTS-CDMA links over channels affected by severe multipath. After coherent combining and despreading, for each user a suitable “Bayesian” memoryless non-linearity gives symbol-by-symbol the expected values of the transmitted data. These are employed for soft removal of inter-symbol and multiple-access interference from the received sequences. The procedure is iterated in a multistage structure until final hard-decisions are taken. The proposed multistage Bayesian MUD exhibits low complexity and better performance (close to the ideal canceller) than other known solutions, even in presence of channel estimation errors