Biorthogonal Frequency Division Multiple Access Cellular System with Angle Division Reuse Scheme

摘要

In conventional OFDMA cellular systems, mobile stations (MSs) suffer from large ICI in fully loaded cellular environments with full cell frequency reuse, especially at the cell-edge. The fundamental cause is that the signals from serving Base Station (BS) and interference BSs, are modulated by same exponential bases, at same subcarrier. In this paper, a generalized low-complexity fractional Fourier transform (FrFT) based biorthogonal frequency division multiple access (B-OFDMA) cellular system with multiple angle division reuse scheme (MADR) scheme for inter-cell interference (ICI) cancellation is proposed. FrFT angle is regarded as a kind of time-frequency combination resource (TFCR), and it can be optimally allocated to each BS of the cellular system, based on simplified minimal base correlation coefficient (MBCC) criteria, which confirms the inner-cell mutual orthogonality between modulating bases at different subcarriers, and inter-cell mutual approximate orthogonality between modulating bases at same subcarriers. Therefore, at the receiver, ICI can be dramatically suppressed by MMSE equalization and correlative detection in respective optimal FrFT domain. Extensive system simulations are conducted for various practical scenarios to demonstrate the superior performance of the proposed FrFT MADR scheme in bit error rate (BER) and system throughput, especially for cell-edge MSs, compared with conventional OFDMA cellular with different ICI cancellation schemes and scheduling schemes.