Spectral-Efficient Band Allocation Scheme for Frequency-Domain Pulse-Shaping-Based SC-FDMA Systems

One major concern of employing frequency-domain pulse shaping (FDPS) to reduce the peak-to-average power ratio of single-carrier frequency-division multiple-access (SC-FDMA) signals is the decrease of system spectral efficiency due to the excess bandwidth wasted in the existing band allocation schemes (BASs). To improve the spectral efficiency of FDPS-based SC-FDMA systems, a novel BAS is proposed, where edge subcarriers for each user are overlapped with those of all its neighbors. However, the spectrum overlapping incurs multiuser interference and degrades the bit error rate (BER) performance. To address this problem, two iterative multiuser detection (MUD) algorithms are proposed based on expectation propagation (EP), termed joint EP (J-EP) and distributed EP (D-EP). Simulation results demonstrate that, aided by either of the EP-based MUD algorithms, the FDPS-based SC-FDMA system with the proposed BAS can work more spectral-efficiently without BER performance degradation compared to those with the existing BASs. In addition, the D-EP algorithm performs nearly the same as J-EP but requires much lower complexity, making it more appealing for large numbers of allocated subcarriers.