, Volume 71, Issue 3, pp 2023-2043
Date: 24 Nov 2012

BER Performance of Walsh–Hadamard Like Kronecker Product Codes in a DS-CDMA and Cognitive Underlay System

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Abstract

Walsh–Hadamard transform, a discrete unitary transform is widely used in many applications such as signature codes in the current wireless standards IS-95 CDMA, WCDMA, CDMA2000 and image transform applications. It is simple to implement this transform since they can be generated by a single Kronecker product recursion formula. In this paper, a new set of binary code families similar to Walsh codes are obtained based on the concept of code concatenation and permutation. It is shown that these codes can be generated by reconfiguring the Walsh–Hadamard code generator. Hence it can be utilized in reconfigurable radios such as underlay cognitive radio (UCR). Theoretical results showing the BER performance due to MAI between primary users and secondary users in an UCR is also obtained. Simulation results showing the BER performance of these codes in a direct sequence spread spectrum system and UCR system with quadrature multiplexing operating in the individual decoding mode under AWGN plus flat fading Rayleigh channel conditions is also obtained.