Power and Spectrally Efficient Multiple Access Using CPM over SC-FDMA

In this paper, we investigate the power efficiency and bit error rate performance of two spectrally efficient CPM-SCFDMA (Continuous Phase Modulated Single Carrier Frequency Division Multiple Access) waveforms. CPM-SC-FDMA is derived by sampling a Continuous Phase Modulated (CPM) waveform and then DFT-precoding the resulting signal samples for transmission using SC-FDMA. Having originated from a constant envelope CPM waveform, CPM-SC-FDMA can potentially retain much of the power efficiency of CPM-thus resulting in a lower peak-to-average power ratio than conventional SC-FDMA. As we show in this paper, when taking the difference in power amplifier backoff requirements into account, CPM-SC-FDMA can provide an overall gain of up to 4 dB relative to convolutionally encoded QPSK-SC-FDMA over a frequency-selective channel.