Decision-Directed Least-Squares Phase

A low-complexity decision-directed iterative scheme is proposed for the estimation

ORTHOGONAL frequency division multiplexing
(OFDM) systems operating in strong levels of phasenoise
(PHN) and frequency offset (FO) are known to suffer
from significant performance degradation due to the high
levels of total-phase perturbation (TPP) induced inter-carrier
interference (ICI), a fact which limits their achievable
performance [1]–[6] and thus makes the use of higherorder
constellations for increased transmission throughput
infeasible. Scenarios of strong phase errors are becoming
of importance due to recent interest in millimeter-wave
low-cost radios [7], [8]. In high frequencies, phase-related
errors are more pronounced because the effect of a noisy
oscillator grows with the square of the carrier frequency.
In the world of ”Dirty RF” as described in [9], new digital
signal processing techniques are needed to deal with higher
levels of impairments, thus relaxing the requirements on
future RF sub-systems.