Adaptive Selection of Spreading Code Subsets from Orthogonal Binary Code Sets for Reduced PAPR in MC-CDMA Systems

Abstract

One of the major concerns with multicarrier CDMA (MC-CDMA) systems is the high peak to average power ratio (PAPR) that can lead to degraded transmission power efficiency. Based on the well known fact that suitable allocation of user spreading codes can be used as a PAPR reduction tool, we in this contribution, investigate the PAPR property of a recently proposed spreading code set called “Orthogonal Binary User (OBU) Codes”. Considering different levels of active user densities, we present code allocation table consisting of selected OBU code combinations yielding low PAPR. On the basis of analytical and simulation results, we show that the presented code allocation table is capable of making the system perform better than the well known Walsh-Hadamard codes from both PAPR and BER perspectives.