Analysis of decorrelating detector employing common spreading code

This paper analyzes a decorrelating detector for synchronous packet CDMA communications where a set of quasiorthogonal code waveforms is generated from a common code by assigning distinct initial code phases to all users. In this analysis, we characterize the residual multiple-access interference (MAI) caused by possible timing offsets when synchronous packet transmissions are on the reverse link of centralized networks. Also, to show the feasibility of the decorrelating detector, we further investigate its robustness against the multipath channel. It is shown that the decorrelating detector greatly reduces the residual MAI to the order of N^-2, N number of chips/bit, and yields acceptable performance even faced with the near-far situation