Iterative Multiuser Interference Reduction :

| We view the asynchronous random{code{ division multiple{access channel as a time{varying convo-lutional code. We study the case where the users encode their data and therefore the single user transmitters and the CDMA channel appear as the concatenation of two coding systems. At the receiver we employ serial Turbo decoding strategies. Unlike conventional Turbo codes where both the inner and outer code may be selected, in our case the inner code is due to the CDMA channel which we assume to be random. Nevertheless, the decoding system resembles the decoder of a serial Turbo code and single user performance is obtained even for numbers of users approaching the spreading code length.