Near-far resistant detection of CDMA signals via isolation bit insertion

This paper presents a novel scheme for near-far resistant CDMA detection: isolation bit insertion (IBI). At the transmitter, isolation bits are inserted into the information bit sequence before modulation, and a practical linear decorrelating detector (LDD) is obtained at the receiver. All the advantages that an LDD theoretically offers are retained and realised in practice.

Synchronisation error resistant multiuser detection for asynchronous CDMA

Linear CDMA detectors have emerged as a promising solution to multiple access interference (MAI) suppression. Unfortunately, most existing linear detectors suffer from high sensitivity to synchronisation errors (also termed parameter estimation error), and synchronisation error resistant detectors have so far not been as widely investigated as they should have. This paper extends the minimum variance distortionless response (MVDR) detector, proposed previously by this author (Zheng 2000) for synchronous systems, to asynchronous systems. It has been shown that the MVDR structure is equally effective for asynchronous systems, especially for the weaker users.