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Underlay Cognitive Radio Wireless Networks using Repetition Coding and Spread Spectrum

Authors:
Saed Daoud
David Haccoun
Christian Cardinal

Keywords: Bit error rate, cognitive radio, repetition coding, quality of service, spread spectrum.

Abstract:
In this paper, we investigate the use of repetition coding (RC) in conjunction with code division multiple access (CDMA) spread spectrum (SS), as a means to spread the signal power of a secondary (cognitive) underlay system, operating at the same time and on the same frequency band with a primary system. First, we consider single user (SU) systems, where we find the bit error rate (BER) at the secondary receiver (SR), satisfying a given quality of service (QoS) requirement for the primary system. Then, we find the maximum coding rate required to satisfy the QoS of both systems. Also, we investigate the combination of RC and SS in multiuser (MU) systems, where SS is used as a means to separate the signals from each others. Simulation results show that, using RC with low coding rate, can maintain the interference level at the primary receiver (PR) below the maximum allowed level, while, at the same time, improving the BER performance of the secondary system. Furthermore, the largest coding rate required to satisfy both systems’ QoS grows fast, as the transmit power of the primary system gets larger than the minimum value for the secondary system to operate. Finally, it is shown that, in some cases, dividing the bandwidth between RC and SS is a better option than allocating the whole bandwidth to SS only.

Pages: 21 to 25

Copyright: Copyright (c) IARIA, 2016

Publication date: February 21, 2016

Published in: conference

ISSN: 2308-4251

ISBN: 978-1-61208-456-5

Location: Lisbon, Portugal

Dates: from February 21, 2016 to February 25, 2016