Blind adaptation of antenna arrays using a simple algorithm based on small frequency offsets

With the development of wireless and personal communication systems, there is considerable interest in using antenna array technology to improve the system capacity in both present and future generation wireless systems. A novel and simple algorithm is proposed for blind adaptive extraction of a binary phase-shift keying (BPSK) signal in the presence of interference by cyclostationary signal processing using an antenna array. The algorithm operates in an interference-limited system in which the desired and interfering signals have identical symbol rates, but are modulated on slightly different carrier frequencies. Compared to existing blind algorithms which also exploit the cyclostationarity of the received signal, the new algorithm provides a simpler and faster converging means to estimate the channel phase for diversity combining. Analytical and simulation results are presented and performances are compared with direct matrix inversion (DMI) and existing blind algorithms. Based on the proposed algorithm and the result obtained by Gardner, Schell and Murphy (1992), a time-division multiple-access (TDMA) system with the new channel assignment scheme called cyclic TDMA (CTDMA) is proposed. The simulation results also show that the proposed algorithm is relatively simple and very promising in applications to indoor wireless communication where interference rejection and increased spectrum efficiency are the objectives. Analysis and simulation results are presented to confirm the interference rejection capabilities. The robustness of existing and proposed algorithms to the perturbation of cyclostationarity is also discussed.