Inter carrier interference and multiple access interference are induced in uplink OFDMA systems due to Carrier Frequency Offset (CFO) which is a mismatch between the transmitter and receiver frequencies that in turn affects the orthogonality among subcarriers. A different CFO value is experienced by each user data and each of these CFO values needs to be estimated and corrected. A novel Extended Viterbi-and-Viterbi (EVAV) algorithm is employed for CFO estimation in the present study. A conventional algorithm for CFO compensation that deals with Minimum Mean Square Error (MMSE) filter output, involves inversion of interference matrix, adding to the computational complexity. The complexity was found to increase with the number of subcarriers. Hence, here an iterative Conjugate Gradient (CG) method is used to compute the MMSE filter output without an inverse operation, thereby reducing the complexity. Both the EVAV method and the CG method have been analyzed in terms of various performance measures. The results showed that they function better than their conventional counterparts. © 2014 IEEE.

Ramachandra Reddy G

Department of Communication Engineering

School of Electronics Engineering

Vellore Campus

Eappen N.I

Arun Prakash J

Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

&nbsp;

&nbsp;

VIT University

Efficient multi user CFO estimation and correction techniques in uplink OFDMA systems

2014 First International Conference on Computational Systems and Communications (ICCSC)

Filter bank multicarrier (FBMC) has emerged as the favourite multicarrier communication technique since it meets the demands of the next-generation standards, especially for communication under doubly dispersive channels. In order to combat the undesirable channel effects like inter symbol interference and inter carrier interference, the prototype filters used in FBMC systems must satisfy orthogonality conditions and be well localized simultaneously in both time and frequency domains. Even though conventional doubly localized filters are optimum in the absence of channel, they fail to satisfy orthogonality and localization criteria under doubly dispersive channels. In the present study, an adaptive filter design method is proposed in which the prototype filter is designed as the weighted sum of a time-limited Nyquist filter, a band-limited Nyquist filter, and doubly localized Gaussian filter based on the analysis of discrete ambiguity function (DAF). The filter is designed to vary its characteristics according to the maximum time and frequency domain dispersions of the channel, so that signal-to-interference ratio is maximized. In order to ensure distortion-less transmission, the perfect reconstruction criterion for distortion-less transmission is mapped to specific conditions for DAF according to two-dimensional channel scattering function. The superiority in performance of the proposed adaptive filter is analysed in terms of signal-to-interference ratio and bit error rate, and is compared with the conventional filters for various channel scattering conditions. © 2018, © 2018 IETE.

IETE Journal of Research

Novel Adaptive Filter Design for Filter Bank Multicarrier System Under Doubly Dispersive Channel Conditions

IET Communications

Blind iterative frequency offset estimator for orthogonal frequency division multiplexing systems

Cummings Otolaryngology - Head and Neck Surgery

Arytenoid Adduction

IEEE Transactions on Wireless Communications

Iterative carrier-frequency offset estimation for generalized OFDMA uplink transmission

IEEE Transactions on Signal Processing

Blind Frequency Synchronization in OFDM via Diagonality Criterion

IEEE Journal on Selected Areas in Communications

Non-data-aided carrier offset estimators for OFDM with null subcarriers: identifiability, algorithms, and performance

Journal	Data powered by Typeset2014 First International Conference on Computational Systems and Communications (ICCSC)
Publisher	Data powered by TypesetIEEE
Open Access	0