Offset modulated single-carrier FDMA with flexible user bandwidth

In this paper, we investigate single-carrier frequency division multiple access (SC-FDMA) transmission with offset quadrature amplitude modulations (OQAM). Firstly, we propose cyclic prefixed OQAM orthogonal frequency division multiplexing (CP-OQAM-OFDM) transmission with unequally-spaced subbands. We then apply it to FDMA transmission and propose a SC-FDMA scheme with the following features: a) the transmit signal of each user is offset modulated single-carrier with frequency-domain pulse-shaping; b) the bandwidth of each user is adjustable; c) the spectral efficiency does not decrease with increasing the roll-off factors. To combat both inter-symbol-interference and multiple access interference in frequency-selective fading channels, a joint linear minimum mean square error frequency domain equalization using a prior information with low complexity is developed. Simulation results confirm the effectiveness of the proposed SC-FDMA transmission.