In this contribution we propose and investigate a transmitter preprocessing scheme for downlink transmission in the multicarrier direct-sequence code-division multiple-access (MC DS-CDMA) systems using multiple base-station antenna arrays and each antenna array using multiple array elements. The transmitter preprocessing scheme is derived based on the singular value decomposition (SVD) approach...

It is well known that some of urban man-made noises can be characterized by a wideband impulsive noise (pure impulsive noise). The presence of this pure impulsive noise may significantly degrade the wireless digital transmission performance. As the data rate becomes higher and the radio bandwidth becomes wider, the performance degradation due to pure impulsive interference may become larger. In...

This paper proposes broadband packet wireless access employing Variable Spreading Factor-Orthogonal Frequency and Code Division Multiplexing (VSF-OFCDM) with two-dimensional spreading that prioritizes time domain spreading in the forward link and Multi-carrier/DS-CDMA (MC/DSCDMA) in the reverse link for the system beyond IMT-2000. Based on the wireless access scheme, we propose major radio air ...

The potentialities of chaos to secure transmitted messages in digital communications has been proved. This by use Direct Sequence Code Division Multiple Access (DSCDMA) system using chaotic spreading sequences. Two synchronization methods for Chua’s digital chaotic generator, are presented: the master-slave synchronization and the impulsive synchronization. In the first method, the driving sign...

The characteristics of spreading sequences significantly affect the performance of the forward link DSCDMA system in fading channel. The bit error rate (BER) is a function of the signal-to-interference ratio (SIR) which has different characteristics depending upon the spreading sequence. In this paper, the SIR is analyzed when orthogonal codes and pseudo random codes are used as the spreading s...

Based on the fast stable convergence characteristics of successive over relaxation (SOR) iterative and Jacobi GaussSeidel (JGS) iterative, a blind adaptive SOR/JGS iterative Kalman multi-user detection (MUD) algorithm (SJK) is proposed for multiple access communication system as direct sequence spread spectrum code division multiple access (DSCDMA) system with multi-path fading channel. The pro...

OFDM, MC-CDMA and DS-CDMA are being researched vigorously as the prospective signaling technique for the next generation mobile communications systems, which will be characterized by the broadband packet technology. With packet transmissions, hybrid ARQ (HARQ) will be inevitable for error control. HARQ with rate compatible punctured turbo (RCPT) codes is one of the promising techniques. Data ra...

An Energy-Efficient DS-CDMA communication and modulation technique for reducing multiple access interference (MAI) as well as for reducing power consumption in DSCDMA wireless sensor LAN systems is presented. Source symbols are represented by a special coding, termed Minimum Energy coding (ME coding), which exploits redundant bits for saving power when transmitted via RF links with On-Off-Keyin...

One of the most important components of any wireless network is the medium access control protocol. This research deals with wireless ATM (WATM) medium access control (MAC) protocol. Conventional studies concerning WATM have focused mainly on variations of the time-division-multiple-access (TDMA) method for the wireless aspect of WATM networks. However, there are many advantages that the direct...

This document outlines a PHY proposal for IEEE 802.16.3 using a combined synchronous DSCDMA (S-CDMA) and FDMA scheme. The proposed PHY features adaptive QAM modulation, high-rate trellis and/or turbo coding, linear equalization along with power and timing control. Purpose To provide a description of a proposed physical layer specification for consideration by the IEEE 802.16.3 Task Group. Notic...