Cyril Plapous, Jun Cheng, Eddy Taillefer, Masaya Hashiguchi, Akifumi Hirata and Takashi Ohira
Interference Cancellation in OFDM Systems and
Reactance-Domain MUSIC Algorithm for ESPAR Antennas
Abstract:On the one hand, this report describes an attempt to apply the Electronically Steerable Parasitic Array Radiator (ESPAR) antenna to an Orthogonal Frequency Division Multiplexing (OFDM) scheme to cancel the delayed signals out of the guard interval. Computer simulation results show good performance for the case where signals impinging on the ESPAR antenna are both in and out of the guard interval. Thanks to its simple hardware structure, the ESPAR antenna can be used aboard user terminals to improve their capacity. On the other hand, a new technique of estimation for Direction-of-Arrivals (DoAs) is proposed for the ESPAR antenna. This technique is based on the modified MUSIC (MUltiple SIgnal Classification) algorithm.
An M-dimension vector y of the output of the antenna is obtained by making a circular shift of a given vector of the reactances M times. Then the M by M correlation matrix of the y vector is employed to estimate the MUSIC spectrum. Simulation results show that DoAs can be estimated by the reactance-domain MUSIC algorithm for the ESPAR antenna.
Key words: ESPAR antenna, multipath cancellation, adaptive beamforming, gradient-based algorithm, MCCC, OFDM, reactance-domain MUSIC algorithm, direction-of-arrival, direction finder, mobile user terminals, low complexity.