Direct detection optical code-division multipleaccess (CDMA) communication systems involving overlapping pulse-position modulation (OPPM) is considered. Double optical hardlimiters placed before and after the correlator at the receiver side is proposed for this system. The performance (in terms of the bit error probability) of this system is evaluated taking into account the effect of both the ...

In this paper, we investigate the influence of different Walsh-Hadamard (WH) code allocation techniques on the performance of multi-carrier code division multiple access (CDMA) systems in the presence of high power amplifier (HPA) non-linearities. We consider two different multi-carrier CDMA schemes: multi-carrier CDMA (MCCDMA) and multi-carrier direct sequence CDMA (MC-DSCDMA) and analyse thei...

A hybrid TDMA/CDMA MAC protocol for WSN is proposed that combines the strengths of TDMA and CDMA while offsetting their weaknesses. The proposed scheme allows the network to operate in a collision-free manner, and takes advantage of broadband property provided by CDMA. The main features of this hybrid protocol are high throughput and low latency. Performance of this new protocol is compared wit...

Mobile radio communication systems are affected by the frequency and time selectivity of radio channel due to multipath propagation and Doppler shifts. In an Orthogonal Frequency Division Multiplexing (OFDM) based Code Division Multiple Access (CDMA) system, the spreading schemes will suffer loss of orthogonality between codewords of different users. In this thesis, basic system model of severa...

In this lecture, we present the mathematical analysis on the average bit error rate for multi-users in a single channel of the spread spectrum, Code Division Multiple Access (SS-CDMA) mobile radio system. We present expressions of BER performance of CDMA systems for a wide range of interference conditions for both synchronous case and asynchronous case, including Gaussian approximations (GA), I...

Abstract MC-CDMA, a multicarrier modulation scheme based on code division multiple access (CDMA) is the most likely candidate for the next generation of mobile radio communications. Rate compatible punctured turbo coded hybrid ARQ (RCPT HARQ) has been found to give improved throughput performance in a DS-CDMA system. In this paper, we apply RCPT HARQ to an MC-CDMA system and evaluate by compute...

This paper studies the trade-off between coding and direct-sequence spreading in a code-division multiple-access (CDMA) system, in the presence of errors in the delay estimate. One extreme is when all spreading is done by forward error correcting codes , referred to as code-spread CDMA (CS-CDMA) systems. CS-CDMA systems have been shown to achieve high capacity, assuming perfect channel knowledg...

In electronics and communication system MC-CDMA(Multi Carrier Code Division Multiple Access) is very attractive choice for high speed wireless communication with bandwidth utilization and BER(bit error rate) performance.MC-CDMA is used in wireless communication to avoid the problem of ISI(intersymbol interference) and also exploit frequency diversity.MC-CDMA system is used to support multiple u...

Multiband CDMA is useful for constructing DSCDMA (CDMA) systems over a non-contiguous spectrum. The method by which users are assigned to their respective frequency bands, termed ‘band allocation’, is an important part of assuring good performance in multiband CDMA systems. This paper proposes a novel approach to band allocation based on the transmission power as it is adjusted by power control...

In this paper we consider a matrix algebraic approach to derive the coded Multi-Carrier CDMA (MC-CDMA) system model for a Doppler shift channel. We derive the eeects of Doppler shift in a MC-CDMA system for low earth orbit (LEO) mobile-satellite communications and show the similarity of a MC-CDMA channel model under Doppler shift with that of the asynchronous DS-CDMA channel model. We therefore...