Code Division Multiple Access (or CDMA) is a multiple access technique based on spectral spreading that has been tremendously successful in the wireless domain. The effectiveness of CDMA in applications like cellular networks, satellite systems and Wireless Local Loop systems has strongly contributed to maintaining the application of CDMA to the optical domain, also known as Optical CDMA, an ac...

A new-design methodology for the design of optimal spread-spectrum sequences for asynchronous code-division multiple acces (A-CDMA) and chip-synchronous CDMA (CS-CDMA) systems is proposed. We derive general results on the partial auto-correlation function of the optimal spreading sequences for CS-CDMA and A-CDMA systems with respect to the minimization of the average bit error rate under the st...

One of the main disadvantage of multi-carrier CDMA (MC-CDMA) signals is the high peak power of the transmitted signals which limits their applications. To account for this issue, we provide a simple signal processing for reducing the high crest factor (CF) of MC-CDMA signals. Using this modified MC-CDMA signal, the high CF due to Walsh spreading sequences can be mitigated without explicit side ...

The 3 generation mobile communication system will base on Code Division Multiple Access (CDMA) system, because CDMA system can provide more capacity than TDMA and FDMA systems. But signal will suffer from the interference called Multiple Access Interference (MAI).This problem can be reduced by using multi-user detection technique. This paper examines the Performance of Parallel Interference Can...

In this paper, we investigate the performance of a recently proposed multiple-access system, namely, partitionspreading CDMA (PS-CDMA). We show via variance evolution that the asymptotic channel throughput of PS-CDMA improves monotonically as the number of partitions increases. The fundamental limit of the PS-CDMA system is calculated by evaluating the spectral efficiency of the layered channel...

Reed-Muller codes are studied for peak power control in multicarrier code-division multiple access (MC-CDMA) communication systems. In a coded MC-CDMA system, the information data multiplexed from users is encoded by a Reed-Muller subcode and the codeword is fully-loaded to Walsh-Hadamard spreading sequences. The polynomial representation of a coded MC-CDMA signal is established for theoretical...

Analog frequency modulated (FM) systems offer advantages of reliable speech quality and simplicity, whereas code division multiple access (CDMA) systems promise high capacity, resistance to multipath fading, and simplified frequency planning. In this thesis, we investigate the performance of a wireless local loop (WLL) system that uses the frequency modulation with the CDMA technique. The perfo...

Abstract The multiple-access interference (MAI) limits the transmission performance of the CDMA uplink transmission. In this paper, we propose a generalized chip-interleaved (GCI)-CDMA with 2-dimensional (2D)-OVSF spreading. Since MAI can be removed, single-user frequency-domain equalization based on the MMSE criterion can be applied for signal detection. The GCI-CDMA allows flexible multi-rate...

In this paper, a multi-coded CDMA system employing a variable spreading gain (VSG) approach is proposed for high-rate applications, which is based on two algorithms for selecting multi-code set. From the simulation results, in addition to simple receiver structure thanks to level clipping, the multi-coded VSG CDMA system provides an high bit rate transmission, while maintaining an acceptable pe...