Performance analysis of linear joint multiple access interference cancellation-equalization for asynchronous multitone CDMA

We analyze the problem of joint equalization and cancellation of the multipath and multiple access interference for multitone CDMA introduced by Vandendorpe (see IEEE Transactions on Vehicular Technology, vol.44, no. 2, p.327, 1995). A linear structure is investigated for an MMSE criterion. In order to understand the potential of the system we first study the steady-state behaviour of the joint equalizer-canceller. The investigation is carried out for a joint device following a receiver made of a bank of matched filters and assuming perfect carrier phase and timing recovery. The scenario is asynchronous. An exact expression in the form of an integral is obtained for the bit error probability of the BPSK symbols before and after cancellation, by means of the characteristic function method. The performance of different systems is obtained for a constrained comparison and the near-far resistance of the detector is demonstrated