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

ABSTRACT

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.

KEYWORDS:

• 5G
• Beyond OFDM
• Discrete ambiguity function
• Doubly dispersive channel
• FBMC

Additional information

Notes on contributors

Arunprakash Jayaprakash

Arunprakash Jayaprakash received his BTech degree in electronics and communication engineering from University of Kerala, Trivandrum, India, in 2008, and his MTech degree from VIT University, Vellore, India, in 2013 and PhD degree from VIT University, Vellore, India, in 2017. He worked as a lecturer in Electronics and Communication Engineering Department of University College of Engineering, Kariavattom, Trivandrum, from September 2009 to May 2011. Currently he is working as ad hoc faculty in the Department of Electronics and Communication of National Institute of Technology, Calicut. His research areas of interest include digital signal processing, digital image processing and signal processing for wireless multicarrier communication systems.

G. Ramachandra Reddy

G. Ramachandra Reddy (SM IEEE'90) received the MSc and MSc (Tech.) degrees from the Birla Institute of Technology and Science, Pilani, India, in 1973 and 1975, respectively, and the PhD degree from the Indian Institute of Technology, Madras, India, in 1987. In 1976, he joined the Department of Electrical and Electronics Engineering, College of Engineering, Sri Venkateswara University, Tirupati, India, as a lecturer, and superannuated as professor in the year 2010. He is currently working as senior professor in the School of Electronics Engineering in VIT University, Vellore, India. He has also served as a dean of School of Electronics Engineering, VIT University, Vellore, India. From February 1989 to May 1991, he was with the Department of Electrical and Computer Engineering, Concordia University, Montreal, QC, Canada, as a visiting scientist. Dr Ramachandra Reddy is a fellow of the Institution of Electronics and Telecommunication Engineers and a member of the Indian Society for Technical Education.