Selection of Spreading Codes for Reduced PAPR in MC-CDMA Systems

One problem with multicarrier CDMA systems is that they often produce large values of peak to average power ratio (PAPR). Here, the correlation properties of the user spreading codes are closely related to PAPR and hence suitable allocation of spreading codes can result in reduced PAPR. In this context, we analyze the PAPR characteristics of a very recently proposed orthogonal set of codes called "Orthogonal binary user codes" and compare them with the well known Walsh-Hadamard codes. In particular, we construct and present a user spreading code allocation table through suitable selection of code subsets from the orthogonal binary user codes that perform better than corresponding Walsh-Hadamard codes.