Hybrid Domain Compensation for Analog Impairments in OFDM Systems

In orthogonal frequency division multiplexing (OFDM) systems with direct-conversion transceivers, transmission performance is severely degraded by analog impairments, typically, carrier frequency offset, transmitter/receiver I/Q imbalance, and DC offset. The existing research considered only part of these impairments. In this paper, we analyze the OFDM signal corrupted by all these impairments. Then, a hybrid domain compensation scheme consisting of the time-domain and frequency-domain compensation is proposed. For the purpose of practical implementation, we also propose a comparable preamble, with which the compensation coefficients can be obtained by a low- complexity acquisition algorithm.