Signal design and spectral efficiency in multi-carrier multiple access systems with PAPR as a parameter

In this paper we investigate a signal design method to increase spectral efficiency and to limit high peak to average power ratio (PAPR) input signal combinations to OFDM sub-carriers. It reduces PAPR level of an OFDM system without decreasing bandwidth utilization. The system design also shows how a set of concatenated Walsh Hadamard (WH) codes can be used to spread a block of information bits to increase number of orthogonal spreading codes while keeping the spreading factor at a low level.