ESPAR antennas-based signal processing for DS-CDMA signal waveforms in ad hoc network systems

Electronically steerable passive array radiator (ESPAR) antennas are capable of spatially forming a beam toward the desired signal with the lowest cost, and are suitable to be employed in ad hoc wireless network systems. We propose a cascaded scheme for ESPAR antenna-based signal processing, where the beam toward the desired user terminal is formed in advance, and the equalizer for direct-sequence code division multiple access (DS-CDMA) signal waveforms is followed. According to the scheme, cochannel user-terminal signals and intersymbol interference signals are respectively suppressed by spatial filtering of the desired beam and the waveform-based adaptive equalization. The steady state and convergence performance of the proposed scheme is illustrated numerically by simulations.