SINR Analysis of a Narrowband Interference Cancellation Scheme in OFDM Communication Systems

Narrowband interference (NBI) is a significant impairment for multi-carrier modulation systems in both wireless and wireline channels. NBI may be generated by switching power supplies and legacy communication systems, and in many instances may be tonal in nature [1]. Recently, a novel method for mitigating the effect of NBI was proposed in [2] which works on minimizing the NBI spectral leakage by downconvering, nulling, and upconverting the received signal. In this paper we address the key question of how the algorithm performs as the number of interferers scales. We perform a distortion analysis on the received signal and obtain the following results under the assumption of an idealized analog front end: a) the distortion scales linearly with the number of interferers b) the distortion is independent of interferer frequency and amplitude. We also carry out a signal-to-interference noise ratio (S!NR) analysis of the proposed algorithm and show a good match between theory and simulation results.