Peak-To-Average Power Ratio Optimization of Hybrid OFDMA and Pre-Coded CDMA Reverse Link

There is an effort by the 3GPP2 (Third Generation Partnership Project 2) standards body to continue to evolve the current Evolution Data-Optimized 3G (EVDO) system into Revision C (EVDO Rev. C). The design goals include achieving much higher spectral efficiency and peak rates, at the same time providing flexibility, backward compatibility and maintaining low complexity in the base stations and mobile systems. OFDM based technologies are promising candidates for this evolution. However, one of the main disadvantages of OFDM is the high time domain peak-to-average power ratio. In this paper, we describe the underlying design philosophy for reducing the peak-to-average ratio of the EVDO Rev. C system. We show, through analyses and simulations, that the proposed hybrid OFDMA and pre-coded CDMA reverse link (RL) has a PAPR advantage over the pure OFDMA system. We also describe a joint clipping and tone reservation method and show that the resulting PAPR is comparable to that of the current EVDO systems.