Low complexity equalization techniques using interference cancellation for SC‐FDMA uplink systems under doubly selective channels

Abstract

This paper addresses the important and challenging issue of joint equalization of carrier frequency offsets (CFOs), timing offsets, and doubly selective channels (DSCs) of multiple users in a SC-FDMA uplink. Low complexity, iterative equalizer solutions are proposed, which give impressive performance under rapidly varying channel conditions. We propose three different equalization schemes that make use of iterative interference cancellation technique named as iterative equalizer with interference cancellation (IEIC), iterative equalizer with interference cancellation and decoding (IEICD), and simplified iterative equalizer with interference cancellation and decoding (SIEICD). The SIEICD method proposed is a simplified version of the IEICD, and it makes use of the only significant elements in the receive signal model in the matrix form. The superior performance of the methods in high mobility conditions with several users is amply demonstrated through extensive simulation studies. KEYWORDS equalization over DSC, joint equalization, single carrier frequency division multiple access SC-FDMA uplink, time and frequency selective channel Abbreviations: IEIC, iterative equalizer with interference cancellation; IEICD, iterative equalizer with interference cancellation; SC-FDMA, single carrier frequency division multiple access; SIEICD, simplified iterative equalizer with interference cancellation. Int J Commun Syst. 2018;31:e3819.wileyonlinelibrary.com/journal/dac