Orthogonal frequency division multiplexing with phase modulation and constant envelope design

Constant envelope OFDM with phase modulation (CE-OFDM-PM) was proposed. The motivation of the CE-OFDM-PM system is to alleviate the high peak-to-average power ratio of conventional OFDM systems. In this paper, we explore more details of CE-OFDM-PM systems regarding bandwidth efficiency and performance under AWGN and multipath channels. A theoretical approach instead of Carson´s rule to analyze bandwidth is proposed. It indicates that bandwidth requirement is determined by factors such as input data variance and modulation index. The analytical results show that the CE-OFDM-PM systems require the same bandwidth as conventional OFDM system when appropriate (low) modulation index is applied in CE-OFDM-PM system. Under the same multipath channel and bandwidth, the performance of CE-OFDM-PM systems is compared to conventional OFDM system with one tap equalizer. The uncoded BER performance of CE-OFDM-PM is getting close when OFDM applies clipping, but power efficiency of CE-OFDM-PM still outperforms OFDM since clipping cannot eliminate PAPR issue