Peak-to-average reduction in MC-CDMA based on using different spreading and despreading codes

We propose a new scheme to reduce the peak-to-average power ratio (PAPR) in a MC-CDMA system. In this scheme, some codes among the family of signature codes used in the system are utilized only for PAPR reduction. A set of spreading codes and only one despreading code are assigned to each user. The user selects its own spreading code among the assigned set based on which one provides lower PAPR. The numerical results show that despite of its simplicity, our proposed approach substantially reduces the PAPR of MC-CDMA system at the expense of not capturing some portions of the transmitted energy in the receiver for some users.