Uplink-Downlink Duality of ICI Cancellation in OFDMA Systems with Carrier-Frequency Offset

In orthogonal frequency-division multiplex access (OFDMA) systems, including uplink and downlink, the carrier- frequency offset (CFO) between the multiple transceivers introduces inter-carrier interference (ICI). In this paper, we first develop the uplink-downlink duality of ICI cancellation in OFDMA systems with CFO, then propose a uniform iterative ICI cancellation scheme that can be applied to both uplink and downlink. In uplink, this scheme acts as the detection at the receiver, while in downlink, it acts as the preceding at the transmitter. Moreover, by the studies of the convergence behavior of the iterations, a sufficient condition for the convergence is given, and it is proved that this iterative scheme is equivalent to the zero-forcing (ZF) scheme, but with much lower complexity. The simulation results indicate that due to the uplink-downlink duality, this iterative scheme can effectively suppress the ICI due to CFO in both uplink and downlink.