In uplink multiuser systems, different timing offset (TO) and/or carrier frequency offset (CFO) of multiple users cause multiuser interference (MUI) to a desired user. In this paper, we propose two different MUI cancellation methods, namely weighted parallel interference cancellation (WPIC) and adaptive interference cancellation filter (AICF), for uplink transmission with generalized frequency division multiplexing (GFDM) waveform over Rayleigh fading channel given the existence of TO and CFO of multiple users. The proposed WPIC performs MUI estimation using the detected data symbol of other users and obtains the optimal weight to maximize the signal-to-interference ratio (SIR) of the desired user. We also propose the AICF that aims to maximize the SIR of the desired user. Based on our SIR expression derived in closed-form in the presence of TO and CFO, the AICF is obtained by solving the Rayleigh quotient problem. Lastly, the impact of multiple antennas at the receiver on MUI cancellation is also analyzed to improve reliability. The simulation results show that the proposed WPIC and AICF effectively eliminate MUI and that the AICF can outperform the WPIC in terms of the SIR and spectral efficiency. In addition, the multiple receiver antennas effectively cancel MUI as the number of antennas goes to infinity.
Bibliographical noteFunding Information:
Manuscript received November 17, 2018; revised February 1, 2019; accepted March 8, 2019. Date of publication March 15, 2019; date of current version June 14, 2019. This work has been supported by the Future Combat System Network Technology Research Center program of Defense Acquisition Program Administration and Agency for Defense Development (UD160070BD). This paper was presented in part at the IEEE Wireless Communications and Networking Conference (WCNC), Barcelona, Spain, April 2018. The associate editor coordinating the review of this paper and approving it for publication was E. K. S. Au. (Corresponding author: Young-Chai Ko.) The authors are with the School of Electrical Engineering, Korea University, Seoul 02841, South Korea (e-mail: email@example.com; firstname.lastname@example.org).
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- Timing offset
- carrier frequency offset
- filter design
- interference cancellation
- multiple antennas
ASJC Scopus subject areas
- Electrical and Electronic Engineering