Radio channel has been a precious resource to manage since the take off of the mobile communications in late 70s. Several techniques have proposed over the years trying maximize utilization while allowing a number of users to share the channel. Among those techniques, CDMA has arisen as one of the most popular ones, and several approaches have been taken following the concept of carrier sensing...

This paper presents the theoretical analysis of the multicarrier-code division multiple access (MC-CDMA) system in slowly time varying frequency selective channel. Chaotic sequences are used as spreading codes of CDMA system with BPSK modulation scheme. Performance improvement in Bayesian estimator in the presence of chaotic sequence is investigated. Under perfect synchronization assumption, bi...

The integration of CDMA and GPS within a single mobile terminal, in support of the FCC E911 initiative, has greatly benefited from the GPS-based synchronisation of the CDMA network. Similar synchronisation is not available in GSM and W-CDMA networks which are, by design, asynchronous in operation, and this makes GPS integration into GSM and W-CDMA mobile terminals more complex and costly. Duffe...

Abstract In direct sequence code division multiple access (DS-CDMA) and multi-carrier (MC)-CDMA, frequency-domain equalization (FDE) based on minimum mean square error (MMSE) criterion can be applied to exploit the channel frequency-selectivity and to improve bit error rate (BER) performance. In MC-CDMA uplink, however, the BER performance significantly degrades due to strong multi-user interfe...

Multi-carrier code division multiple access (MC-CDMA), direct sequence code division multiple access (DS-CDMA) and orthogonal frequency division multiplexing (OFDM) are the major contenders for wireless signaling technique. For higher data rates, the use of higher level data modulation is desirable. In MC-CDMA [1], the data-modulated symbol to be transmitted is spread over a number of subcarrie...

Relying on symbol blocking and judicious design of user codes, this paper develops a Generalized Multicarrier (GMC) quasi-synchronous CDMA system capable of multiuser interference (MUI) elimination and inter-symbol interference (ISI) suppression, irrespective of the wireless frequency selective channels encountered in the uplink. As the term reveals , GMC-CDMA provides a unifying framework for ...

Recently, the new spreading sequence obtained by the Weyl sequence is proposed for CDMA systems. Its crosscorrelation function follows O( 1 N ), where N is the code length of the spreading sequence. In this paper, we optimize the Weyl sequence code design to assign to each user for CDMA systems and we analytically calculate its theoretical SIR (Signal to Interference Noise Ratio). It is theoret...

Conventional DS-CDMA systems employ a RAKE receiver in an attempt to make full use of the signal energy scattered in the time domain; however, the multipath effect causes a loss of orthogonality which degrades RAKE receiver performances. The literature on multi-carrier CDMA (MC-CDMA) has shown that receivers employing frequency diversity (in an effort to make full use of energy spread in the fr...