Performance evaluation of multirate DS‐CDMA communication systems with adaptive antennas

Abstract

Adaptive antennas, with spatial processing, used in code division multiple access (CDMA) systems can enhance range, reliability, and capacity. Moreover, the adaptive beamforming technologies can remove unwanted noise and interference from the received signal. In this paper, we propose the adaptive direct sequence (DS) CDMA antenna receivers and compare their performances in three existing multirate methodologiesvariable processing gain (VPG), variable chip rate, and multicode systems for multiuser communications in multipath fading channels. Simulation results show that the processing powers of both narrowband and wideband adaptive antennas are not enough. We propose a powerful processing technique named Wiener Code Filter (WCF) to retrieve the shortcomings. Mean square error (MSE) analyses are also given in this paper. Some simulation examples are given to compare the performances of the proposed multirate structures. Copyright (c) 2010 John Wiley & Sons, Ltd

A dense overlapped linear subarray architecture for interference suppressing in small‐scale arrays

“…Owing to the merits such as lower interference [1,2], better spatial reuse, longer transmission range [3], and improved network capacity [4,5], the adaptive digital beamforming (ADBF) has been studied in various of areas. Radio interference suppressing ability is the key advantage of adaptive arrays, especially for the strong radio frequency interference in the same frequency band and has been applied extensively in global navigation satellite system (GNSS) receivers for the severe electromagnetic environment [6,7].…”