Crest Factor Reduction in MC-CDMA Employing Carrier Interferometry Codes

This paper addresses signal compactness issues in MC-CDMA employing carrier interferometry codes using the measure of crest factor (CF). Carrier interferometry codes, applied to -carrier MC-CDMA systems, enable users to simultaneously share the system bandwidth with minimal degradation in performance (relative to the -orthogonal-user case). First, for a fully loaded ( and users) MC-CDMA system with practical values of , it is shown that the CF in downlink transmission demonstrates desirable properties of low mean and low variance. The downlink CF degrades when the number of users in the system decreases. Next, the high CF observed in the uplink is characterized and the poor CF in a partially loaded downlink as well as uplink is effectively combated using Schroeder's analytical CF reduction techniques.