Escalating demand of higher data rate in progressive generations for wireless environment involve work towards modification of modulation schemes over air interface. Beginning from TDMA/FDMA/CDMA based 2nd generation to highly complicated Orthogonal FDMA (OFDMA), Single Carrier FDMA (SC-FDMA), Interleaved FDMA (IFDMA) and Multicarrier CDMA (MC-CDMA) which are gaining attention for 4G networks. ...

Many recent standards in telecommunications field are based on CDMA spread spectrum transmissions. In this paper, we describe a methodology for top-down design, modeling, and simulation of CDMA transmitter system using hardware description language VHDL-AMS. Details of VHDL-AMS implementation for each elementary block are shown. This paper together with the developed library of CDMA transmitter...

In this contribution, we consider the effect of carrier phase jitter on the performance of uplink OFDMA, uplink multicarrier CDMA (MC-CDMA) and uplink multicarrier direct sequence CDMA (MC-DS-CDMA) systems, assuming orthogonal spreading sequences. For this aim, it is proposed, first to consider a small random jitter, then, to model phase jitter by Gaussian and Rayleigh laws. Theoretical express...

This work is aimed at investigating the use of neural network-based adaptive receivers for synchronous variable bit-rate Multi-Carrier CDMA systems transmitting over low-earth-orbit (LEO) satellite channels. It is known by literature that MC-CDMA techniques are much more resilient with respect to multi-user interference effects in multipath fading channels than single-carrier DS/CDMA ones. More...

Random Packet CDMA: Reducing Delay and Increasing Throughput of WLAN Systems Roland Kempter and Behrouz Farhang-Boroujeny Department of Electrical and Computer Engineering, University of Utah, USA Abstract— We revisit Random Packet Code Division Multiple Access (RP-CDMA), a recently proposed Physical/MAC layer scheme for wireless CDMA networks. We revise earlier results by adopting a more reali...

The Performance comparison of Minimum Mean Square Error-based Adaptive Multi-User Detection (MUD) of Direct Sequence-Code Division Multiple Access (DS-CDMA) signals is considered. DS-CDMA is a popular multiple-access technology for wireless communication. But its performance is limited by multiple-access interference (MAI) and multipath distortion. Adaptive techniques, such as least mean square...

In this paper, the error performance of an MC-CDMA system is analysed with the help of Quadrature Phase shift Keying (QPSK) as the modulation technique mixed up with Additive White Gaussian Noise (AWGN) in the Rayleigh channel. CDMA suffers with the problem of selective frequency diversity during the downlink process. Orthogonal Frequency Division Multiple Access (OFDMA) techniques combine with...

Relying on symbol blocking and judicious design of user codes, this paper builds on a Generalized Multicarrier (GMC) quasi-synchronous CDMA system capable of multiuser interference (MUI) elimination and intersymbol interference (ISI) suppression with guaranteed symbol recovery, regardless of the wireless frequency selective channels. GMC-CDMA provides a unifying framework for multicarrier (MC) ...

W-CDMA and SW-CDMA air interfaces are based on code division multiple access and as in all spread spectrum systems the initial acquisition procedure is a challenging issue. This procedure is identified as cell search in W-CDMA and beam search in SWCDMA. Although the terrestrial air interface W-CDMA and the satellite one SW-CDMA are very similar, the suggested cell/beam search procedures are dif...

Multicarrier code-division multiple-access is one of the effective techniques to gain its multiple access capability, robustness against fading, and to mitigate the ISI.In this paper, we propose an improved mulcarrier CDMA system with adaptive subchannel allocation. We analyzed the performance of our proposed system in frequency selective fading environment with narrowband interference existing...