 
Summary: A NonIterative Technique for Phase Noise
ICI Mitigation in PacketBased OFDM
Systems
Payam Rabiei, Student Member IEEE, Won Namgoong Senior Member IEEE,
and Naofal AlDhahir, Fellow IEEE,
Abstract
In this paper, a practical approach for detecting packetbased orthogonal frequency division
multiplexing (OFDM) signals in the presence of phase noise is presented. An OFDM packet
consists of several OFDM symbols with fullpilot symbols at the beginning followed by consecutive
data symbols. Based on the fullpilot OFDM symbol, a frequencydomain joint phase noise and
channel vector estimator is first derived. It is shown that the phase noise vector can be estimated by
maximizing a constrained quadratic form without requiring knowledge of the channel vector. This
estimated phase noise vector is then used to compute the least squares channel estimator. Assuming
that the channel is constant during each packet, the estimated channel is used in subsequent data
OFDM symbols for equalization and data detection. Since phase noise changes from one OFDM
symbol to the next, the scattered pilots in each data OFDM symbol are used to noniteratively
estimate and mitigate the phase noise induced interference. A significant improvement in the signal
tointerferenceplusnoise ratio is achieved using our proposed algorithms.
This work was supported in part by the National Science Foundation (NSF) under contract CCF 0733124 and by a gift
from Research In Motion (RIM) Inc.
