DS-CDMA with minimum mean square error frequency-domain equalization (MMSE-FDE) can provide much better performance than that with rake combining in a frequency-selective fading channel and is comparable to that of MC-CDMA with MMSEFDE. Chip interleaving is a form of channel interleaving that improves the DS-CDMA performance by converting the channel into a highly time-selective channel; the ti...

In this contribution we propose and study a multicarrier direct-sequence code-division multiple-access (MC DSCDMA) scheme, which employs both time (T)-domain and frequency (F)-domain spreading. We investigate the achievable detection performance in the context of synchronous TF-domain spread MC DS-CDMA, when communicating over an additive white Gaussian noise (AWGN) channel. The performance of ...

The spectral efficiency of single-cell DSCDMA systems deploying higher order modulation schemes is investigated for the downlink in presence of fading channels. Therefore, the asymptotic analysis (AA) is evaluated for random and orthogonal Haar distributed spreading codes to obtain the signal-to-interference-andnoise ratio (SINR) after the optimal and a suboptimal linear MMSE detector. An exten...

Capacity analysis in wireless communication systems is essential for system design, call admission control and radio resource allocation. Since CDMA is a kind of powerconstrained or interference-limited system, its system capacity is not so “hard” as in bandwidth-limited systems, such as TDMAbased systems. In this paper, we analyze the uplink and downlink capacity of multimedia DS-CDMA systems ...

Direct sequence code division multiple access (DSCDMA) is a popular wireless technology. This system suffers from Multiple Access Interference (MAI) caused by Direct Sequence users and Near –far effect. Multi-User Detection schemes are used to detect the users’ data in presence of MAI and Nearfar problem. In this dissertation, we present comparative study between linear multiuser detectors and ...

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 contribution we investigate the performance of RS coded DS-CDMA using M-ary orthogonal signalling over multipath Rayleigh fading channels. `ErrorsAnd-Erasures (EAE)' RS decoding is considered, where erasures are declared based on the joint Maximum Output and Ratio Threshold Test (MOR-TT). Two classes of diversity reception techniques suitable for noncoherent M-ary detection are invoke...

Wideband CDMA (WCDMA), a widely accepted thirdgeneration interface, is based on direct-sequence (DS) CDMA technology. To minimize distortion of the signals in a DSCDMA system, a rake receiver is used. A signal transmitted through the wireless channel may be severely distorted due to co-channel interference, adjacent channel interference (or multiple access interference), thermal noise, and mult...

INTRODUCTION systems are expected to achieve the following goals: • Quality of service (QoS) provisioning Packet-based data services (probably using mobile IPv6) Parallel data streams with different QoS classes (supporting hierarchical source coding and video streaming, for example) Low delay • System scalability (w.r.t. data rates, bandwidth, cell sizes, etc.) High peak rates (about 100 Mbps f...