Constrained Least-Squares Estimation and Compensation of Phase Noise in OFDM Radio Link

We propose iterative least-squares based compensation algorithms for the in-band phase noise distortion of an orthogonal frequency division multiplexing (OFDM) signal. In particular, we impose constraints on the least-squares estimates of the spectral components of the phase noise process which are subsequently used for phase noise compensation. The constraints stem from the fact that the norm of the vector composed of these spectral components is always one, i.e., the vector is always drawn from a hypersphere of radius one. Through simulations, the performance, in terms of bit-error-rate, of the new least-squares estimators with the different constraints are then compared with the unconstrained least-squares case.