Multiple level orthogonal codes and their application in MC-CDMA systems

Authors:
Jingtao Zhang;David W. Matolak
Affiliations:
School of Electrical Engineering & Computer Science, Stocker 334, Ohio University, Athens, OH 45701, United States;School of Electrical Engineering & Computer Science, Stocker 334, Ohio University, Athens, OH 45701, United States
Venue:
Computer Communications
Year:
2009

Citing 6
Cited 1

N-shift cross-orthogonal sequences

IEEE Transactions on Information Theory
Principles of mobile communication (2nd ed.)

Principles of mobile communication (2nd ed.)
CDMA Systems Engineering Handbook

CDMA Systems Engineering Handbook
Multi-Carrier and Spread Spectrum Systems

Multi-Carrier and Spread Spectrum Systems
FG-MC-CDMA System Performance in Multi-band Channels

CNSR '08 Proceedings of the Communication Networks and Services Research Conference
A multicarrier CDMA architecture based on orthogonal complementary codes for new generations of wideband wireless communications

IEEE Communications Magazine

MLO spreading codes for CDMA systems using DCT/DST

RWS'09 Proceedings of the 4th international conference on Radio and wireless symposium

Quantified Score

Hi-index	0.24

Visualization

Abstract

This paper proposes the use of multiple level orthogonal (MLO) codes in multicarrier CDMA (MC-CDMA) systems. It is extremely challenging to improve system error probability performance of MC-CDMA systems with binary spreading codes in multi-user conditions, since attainable-diversity performance is severely degraged by multi-user interference (MUI) in frequency-selective fading channel conditions, even with the use of optimum multi-user detection (MUD) methods. MLO codes are shown to improve system error probability performance in heavily-loaded or fully-loaded systems, in comparison to binary codes. Some widely used MLO code generation methods are summarized, and a new generation method is also provided. The performance advantage of MLO codes over binary codes is analyzed by treating the spreading process in MC-CDMA as a coding process and via analysis of pair-wise sequence error probability. Rules for choosing desirable MLO codes for multi-user MC-CDMA are also given. Numerical results show that MLO codes can provide a substantial performance improvement in fully-loaded systems. For example, for a K=4 user system with spreading gain L=4, our system can obtain a diversity order of 3, whereas the binary code system diversity order is only slightly larger than 1. The MLO code application provides a new way to compensate for multi-user interference (MUI) and makes MC-CDMA more attractive for future high data-rate transmission systems.