Generalized Frequency-Domain Filtered Single-Carrier Signal Transmission

Abstract Single-carrier (SC) transmission is a transmission equipped with frequency-domain equalization (FDE) is suitable for uplink transmission because of its low peak-to-average power ratio (PAPR) property. Square-root Nyquist filtering is widely used, where the filter shape is controlled by the roll-off factor  from 0 to 1. Nyquist filtering with =1 occupies twice bandwidth of the original signal. SC signal can be generated by inserting discrete Fourier transform (DFT) block in orthogonal frequency division multiplexing (OFDM). This realizes an introduction of various frequency-domain signal processing into SC signal transmission. In this paper, we introduce a generalized frequency-domain transmit filtering to SC transmission equipped with FDE (SC-FDE). The transmitted data is initially transformed to the frequency-domain signal and then copied over the available frequency spectrum before applying filtering. Any transfer function can be used and the filtered signal bandwidth can be arbitrary chosen in order to obtain more frequency diversity gain. The transmit filtering with >1 is equivalent to spread spectrum technique in the time-domain and frequency-domain. Performance of the proposed generalized filtered SC-FDE is evaluated by computer simulation in aspect of PAPR and bit-error rate (BER), and compared to the time-domain spread spectrum scheme. The advantages and disadvantages of the proposed generalized SC-FDE and the time-domain spread spectrum scheme are also discussed. Keyword Single-carrier (SC) transmission, transmit filtering, spread spectrum (SS)