SUMMARY We propose multitone-hopping code-division multiple access (MH-CDMA) using a feedback-controlled hopping pattern (FCHP) (FCHP/MH-CDMA). In the FCHP/MH-CDMA, part of the filter coefficients of an adaptive finite-duration impulse response (FIR) filter receiver are fed back to a transmitter, in which they are used as an updated hopping pattern. Each chip of the updated hopping pattern cons...

A fully asynchronous random wireless channel access protocol and transmission system based on CDMA with random spreading, termed Random Packet CDMA [1, 2], is presented. We show that RP-CDMA has the potential to achieve the capacity of the wireless channel. Furthermore, a novel non-linear receiver termed Partitioned-Spreading (PS) is introduced, which allows for significantly higher system load...

One of the promising wireless access techniques for the next generation mobile communications systems is multi-carrier code division multiple access (MC-CDMA). MC-CDMA can provide good transmission performance owing to the frequency diversity effect in a severe frequency-selective fading channel. However, the bit error rate (BER) performance of coded MC-CDMA is inferior to that of orthogonal fr...

Direct Sequence (DS) Code Division Multiple Access (CDMA) systems are considered for a variety of wireless applications and services because DS-CDMA enables the transmission of multimedia messages such as voice, data and video. The performance of Quasisynchronous DS-CDMA (QSCDMA) communication system with a maximal ratio combiner (MRC) over a frequency selective time non-selective multipath Gen...

Abstract Multi-carrier direct sequence code division multiple access (MC DS-CDMA) is a combination of time-domain spreading and orthogonal frequency division multiplexing (OFDM), while multi-carrier code division multiple access (MC-CDMA) is a combination of frequency-domain spreading and OFDM. In MC-CDMA, a good bit error rate (BER) performance can be achieved by using frequency-domain equaliz...

In this paper, we propose a hybrid pulse position modulation/ultrashort light pulse code-division multiple-access (PPM/ULP-CDMA) system for ultrafast optical communications. The proposed system employs spectral CDMA encoding/decoding and PPM with very short pulse separation. The statistical properties of the encoded ULP are investigated with a general pulse model, and the performance of the pro...

For various quasisynchronous (QS) CDMA systems such as LAS-CDMA system which emerged recently, in order to reduce or eliminate the multiple access interference and multipath interference, it is required to design a set of spreading sequences which are mutually orthogonal within a designed shift zone, called orthogonal zone. For traditional orthogonal sequences, such as Walsh sequences and ortho...

The demand for higher data rates along with variable QOS and variable bandwidths has led to the remarkable advancements in the communication technology. To meet the above-listed objectives, whereas the TDMA and WDMA require complex protocols and extensive hardware, the CDMA systems are much simpler and very easily support the above-mentioned services. Since optical CDMA systems assigns unique c...

In this paper we propose a new Wide band Multicarrier (W-MC) Code Division Multiple Access (CDMA) scheme that delivers a great immunity against multi-user interference (MUI) caused by interferers in the system and from which the classical MC-CDMA suffers considerably. For the synchronous-case, the results show that the new system performance was comparable to a single-user system. This exceeds ...

In this paper, we propose two classes of multivalued signature sequences for direct sequence code division multiple access (DS/CDMA) systems. The proposed classes are obtained from the coefficients of the subbands of perfect reconstruction quadrature mirror filterbanks (PR-QMF). The first and second classes are derived from the tree and lattice structure PR-QMF banks, respectively, and they bot...