Orthogonal frequency division multiplexing (OFDM) is a multicarrier modulation technique that is widely used in wireless broadband communication systems. The spectral efficiency of OFDM is very high since the subcarriers are spaced as closely as possible while maintaining orthogonality. However, one of the major problems with OFDM that can cause performance degradation is carrier frequency offs...

In wireless communications systems, Orthogonal Frequency Division Multiplexing (OFDM) and Multiple Input Multiple Output (MIMO) are used to improve spectral efficiency and spatial diversity. Beamforming is used to improve bandwidth utilization. It increases the network range in wireless systems. The main challenge of OFDM system is Carrier frequency offset (CFO). The project focuses on CFO esti...

An improved Central Force Optimization (CFO) algorithm for antenna optimization is presented. CFO locates the global extrema an objective function to be maximized, in this case antenna directivity, by flying “probes” through the decision space (DS). The new implementation includes variable initial probe distribution and decision space adaptation. CFO’s performance is assessed against a recogniz...

In this paper, an extended H∞ filter-based carrier frequency offset (CFO) estimator is proposed for orthogonal frequency division multiplexing (OFDM) systems. The design criterion of the proposed estimator is to minimize the effect of worst-case disturbances (noise and model error) on the CFO estimation errors. This data-aided CFO estimator does not require any statistical knowledge of the dist...

In this paper, we study the channel estimation in the presence of the receiver in-phase and quadrature-phase (I/Q) imbalance and carrier frequency offset (CFO) for orthogonal frequency division multiplexing (OFDM) systems using pilot symbols. The concept of channel residual energy (CRE) [9] is used to solve the joint estimation problem. By minimizing the CRE, we can jointly estimate the receive...

The two most important parameters to be considered while designing an OFDM based communication system are phase noise and carrier frequency offset (CFO). It has been observed that the OFDM systems are very sensitive to phase noise and CFO, and an accurate prediction of the tolerable values of these parameters can help the system to relax the specifications. This paper analyses the performance o...

Orthogonal frequency division multiplexing (OFDM) has developed into a popular scheme for wideband digital communications used in consumer applications such as digital broadcasting, wireless networking and broadband internet access. In the OFDM system, carrier frequency offset (CFO) causes intercarrier interference (ICI) which significantly degrades the system error performance. In this paper w...

In this paper we consider physical-layer network coding (PLNC) in OFDM-based two-way relaying systems. Practically, a key impairment for the application of PLNC is the carrier frequency offset (CFO) mismatch between the sources and the relay, which can not be compensated completely in the multiple-access (MA) phase. As this CFO mismatch results in inter-carrier interference (ICI) for OFDM trans...

Carrier Frequency Offset Estimation for Orthogonal FrequencyDivision Multiplexing Systems Xiang Nian Zeng, Ph.D. Concordia University, 2008 Orthogonal frequency division multiplexing (OFDM) is an attractive modulation scheme used in wideband communications because it essentially transforms the frequency selective channel into a flat fading channel. Furthermore, the combination of multiple-input...