A novel transmit diversity scheme for LTE-Advanced uplink

Abstract

Nx SC-FDMA has been accepted as one of the main multiple access schemes for LTE-Advanced, which has been attracted much attention for supporting extended bandwidth. The classical transmit antenna diversity technique as Space-Frequency Block Coding (SFBC) will destroy the order and structure of the original symbols and thus enhance the peak-to-average power ratio (PAPR). To solve this problem, a modified scheme of SFBC compatible with low PAPR is proposed in this paper. In order to achieve more diversity gain, a new subcarrier mapping method is proposed by which one turbo coded stream is transmitted from multiple frequency bands of Nx SC-FDMA system. The proposed SFBC scheme is based on the groups rather than the symbols which remains the same signal distribution as the equivalent conventional transmission to reduce the PAPR. Due to the channel varying in frequency domain during one turbo coded stream, the new subcarrier mapping method has mapped the one turbo coded stream to the different frequency bands to achieve multiple-branch frequency diversity gain. Simulation results show that the proposed transmit diversity scheme has good PAPR and Block Error Rate (BLER) on frequency selective MIMO channels.