A Time-domain Phase Noise Mitigation Algorithm for OFDM Systems in the Wireless Backhaul Links

The oscillator phase noise (PN) is one of the bottlenecks toward increasing the modulation order in the OFDM-based wireless backhaul links. This paper presents an algorithm to overcome this barrier through a novel time-domain iterative phase noise mitigation method. In the first step, by leveraging the high signal-to-noise ratio of the backhaul links, the PN estimation problem in the OFDM system is formulated similar to the PN estimation in the single carrier system, for which several solutions are proposed in the literature. Subsequently, a decision directed approach is used to solve this estimation problem, which relies on the linear interpolation of refined estimates of the PN. The proposed algorithm secures a significant improvement in the phase noise suppression of the OFDM systems in the high signal-to-noise-ratio regime. By requiring small pilot overhead while avoiding computationally complex operations in the algorithm's iterations, the proposed method is tailored specially for the OFDM-based wireless backhaul links. Numerical results verify the effectiveness of proposed PN mitigation scheme.