A New Trellis Shaping Design for Peak Power Reduction of SC-FDMA Signals With High-Order QAM

Single-carrier frequency-division multiple-access (SC-FDMA) has been adopted as the uplink radio access scheme of the fourth-generation mobile wireless communication system because of its signal with lower peak-to-average power ratio (PAPR) compared to multicarrier based signals. However, when it is combined with high-order quadrature amplitude modulation (QAM) for higher bandwidth efficiency, the SC-FDMA signal also exhibits relatively high PAPR, and thus, the resulting efficiency of power amplifier (PA) will be considerably reduced. Since PA is a dominant source of power consumption at the transmitter, further reduction of PAPR should be necessary in view of future green cellular systems. In this paper, we propose a new trellis shaping (TS) design for peak power reduction of SC-FDMA signals. We first observe that the direct application of the TS developed for peak power reduction of conventional single-carrier signals tends to incur high peaks at the edges of each SC-FDMA signal due to their circularly periodic structure. We tackle this problem by introducing a novel modification of TS such that the symbols at one edge can be controlled by those located at the other edge. It is shown that the SC-FDMA signal with the proposed TS is able to significantly improve the PA efficiency. We demonstrate its effectiveness by investigating system level performances, such as the achievable PA efficiency and resulting power spectral density, as well as its symbol error rate (SER) over additive white Gaussian noise channels with frequency-selective Rayleigh fading in the presence of PA nonlinearity.