Selected mapping technique for reducing PAPR of single-carrier signals

Single-carrier transmission with frequency-domain equalization (SC-FDE) is widely known as a promising transmission technique providing low error probability with low peak-to-average power ratio (PAPR) of transmit signal. However, the low-PAPR property of SC-FDE cannot be maintained if multi-level data modulation is introduced. The low-PAPR property of SC-FDE can be maintained by applying transmit filtering with roll-off factor at the expense of spectrum efficiency. In this paper, we propose two types of selected mapping (SLM) to reduce the PAPR of SC-FDE transmit signal. The first SLM technique is conducted in the frequency domain, where the phase rotation is applied to subcarriers similar to the SLM technique for orthogonal frequency division multiplexing transmission. The second SLM technique is conducted in the time domain, where the phase rotation is applied directly to data-modulated symbol sequence. Computer simulation confirms that both SLM techniques are able to reduce the PAPR of SC-FDE signal without significant degradation of bit-error rate performance and spectrum efficiency.