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

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, the authors in this paper, investigate the PAPR property of a recently proposed spreading code set called "Orthogonal Binary User (OBU) Codes". Considering different levels of active user densities, they present code allocation table consisting of selected OBU code combinations yielding low PAPR.