Abstract
In this letter, the properties of two-path successive relaying systems are exploited to develop an iterative decision directed algorithm to estimate in-phase/quadrature-phase mismatch parameters occurring at the transmitters, relays, and destination for the uplink orthogonal frequency-division multiple access transmission. These parameters along with the actual channel taps of different links are treated as a single unknown parameter to be estimated. A space-alternating generalized expectation-maximization tool is employed to compute the maximum-likelihood estimate. The proposed algorithm iterates between data detector and estimator in order to refine the estimation process. Simulation results confirm the effectiveness of the proposed estimator.