|We introduce a CDMA system based onmulticarrier spread spectrum (MC-SS) with one identical code for all users. In general, the employment of a multi-carrier transmission technique would increase the dynamic range of the correspondent lowpass time signal, and therefore would require a highly linear power ampli er. By carefully designing the code of a MC-SS signal a signi cant decrease of severa...

In the present paper an attempt is made to compare multicarrier and single carrier modulation schemes for wireless communication systems with the utilization of fast Fourier transform (FFT) and its inverse in both cases. With the assumption that in OFDM (orthogonal frequency division multiplexing), the inverse FFT transforms the complex amplitudes of the individual sub-carriers at the transmitt...

In this paper, we study the physical layer security (PLS) problem in the dual hop orthogonal frequency division multiplexing (OFDM) based wireless communication system. First we consider a single user single relay system and study a joint power optimization problem at the source and relay subject to individual power constraint at the two nodes. The aim is to maximize the end to end secrecy rate...

A new method for generating families of ternary spreading sequences is presented. The sequences have aperiodic zero correlation zones and large families are created for a specific sequence length. The sequences are proposed as spreading sequences to provide high capacity and cancel multipath and multiple access interference (MAI) in a single carrier (SC) or multi-carrier (MC) direct-spread code...

ISSN 2250 – 110X | © 2011 Bonfring Abstract--Communication plays very important role in day-to-day life of people. Due to fast growing age, multi carrier communication is preferred over single carrier waves for better transmission. One of the advantages of OFDM system over the single carrier system is the better performance in multipath environment. For narrowband operation, one may construct s...

In this paper, an overlapped Orthogonal Frequency Division Multiplexing (OFDM) named as Fast-OFDM system and an overlapping multi-carrier direct-sequence code division multiple access (MC-DS-CDMA) scheme are introduced. The effect of the overlapping between sub-carriers, of Fast-OFDM and MC-CDMA with binary phase shift keying (BPSK), on the performance in an additive white Gaussian noise (AWGN)...

In this paper, we introduce a novel signal shaping approach for multi−carrier systems. We propose to combine Hermite functions in order to get a good time−frequency localization property for multi−carrier signals, which is important for robustness against the time−frequency dispersion of the wireless channel. In our work, we orthogonalize the linear combination of Hermite functions in order to ...

A new method for generating families of ternary spreading sequences is presented. The sequences have aperiodic zero correlation zones and large families are created for a specific sequence length. The sequences are proposed as spreading sequences to provide high capacity and cancel multipath and multiple access interference (MAI) in a single carrier (SC) or multi-carrier (MC) direct-spread code...

This paper presents an analysis of the effect of the carrier frequency offset and phase noise on a performance of Wavelet based Filtered Multi-Tone (WFMT) systems for a general AWGN channel. It is well known that the carrier frequency offset in OFDM System yields to significant degradation of the signal-tonoise ratio (SNR). Below I show that a novel WFMT modulation is less sensitive to the freq...