Multi-carrier code division multiplexing (MC-CDM) is one of promising multiplexing techniques for fourth-generation mobile downlink communications systems, where high data rate services should be provided even for high speed-cruising mobiles. For MC-CDM-based packet communication, a frequency scheduling method, which adaptively assigns different sub-carriers to different users, is proposed. Thi...

Multi-Carrier Code Division Multiple Access (MC-CDMA) system performance is evaluated with Convolutional error control coding in this paper. Multiple antennas are used at transmitting and receiving side to improve the performance. Various types of equalization schemes are examined. 2x2 antennas considered and code rate of convolutional encoder is 1⁄2. AWGN and Rayleigh fading channel is conside...

The feasibility of a multi-carrier system for data-transmission over copper wires at gigabit rates is analyzed. More specific, we look at the effects of jitter and duty-cycle deviations on the SNR and error rate using Matlab simulations. Jitter causes crosstalk between the inphase and quadrature channels of a given tone frequency. Given a certain rms jitter variance, low frequency tones can car...

In this Paper, we studied the Multi-carrier Differential Chaos Shift Keying (DCSK) modulation. DCSK system provides robustness, higher data rates and optimized the transmitted energy efficiency (EE) as compared to traditional multi-carrier spread spectrum modulations. In this scheme, each binary data is mapped to two chaotic sequences each of the transmitted bits consist of two parts, where one...

Abstract -Orthogonal frequency division multiplexing is a scheme of encoding digital information on numerous carrier frequencies. The orthogonality permits an proficient modulator and demodulator realization by means of FFT algorithm resting on receiver side, and inverse FFT resting on sender side. A substitute technique for orthogonal transmission and reception of data using Rajan Transform an...

Multi-carrier DS-CDMA has been considered as an eeective scheme for reducing multiple access interference in the case of quasi-synchronous transmission. The scheme allows the reduction of multiple access interference by transferring the or-thogonality property of the signals into the frequency domain where the orthog-onality property is robust to relative chip oosets between the spreading codes...

Wireless communication systems are tending towards progressive data transfer over a long range of transmission. With the raise in required quality of services, the allocation of the available resource is to be maintained efficiently. A load matrix approach for multi cellular architecture is proposed, which allocate the communication power based on channel estimated SINR. The allocation of power...

Abstract In this paper, new multiple access schemes based on the combination of Code Division Multiple Access (CDMA) and Multicarrier modulation (also known as OFDM (Orthogonal Frequency division Multiplexing)) are reviewed. Some of the main systems proposed to date are identified and the advantages of such systems discussed. A description of a simulation platform developed to analyse the perfo...

Multi-carrier (MC) signal has a large peak to mean envelope power ratio, so that the MC signal suffers from a high level of inter-modulation distortion due to the nonlinearity of the power amplifier stage. For portable terminals, it is undesirable to use linear amplifiers because high power efficiency is needed. To solve this problem, we propose a time division duplex (TDD)–code division multip...

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...