Radius-aided QRM-MLD for faster-than-Nyquist non-orthogonal FDM systems

• Published in: Optics communications Vol. 458; p. 124742
• Main Authors: Guo, Mengqi, Qiao, Yaojun, Zhou, Ji, Tang, Xizi, Liu, Shuangyue, Xu, Xuekai
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.03.2020
• Subjects: Faster-than-Nyquist non-orthogonal frequency-division multiplexing (FTN-NOFDM); Inter-carrier interference (ICI); Radius-aided maximum likelihood detection with QR decomposition and M-algorithm (QRM-MLD); Faster-than-Nyquist non-orthogonal frequency-division multiplexing (FTN-NOFDM); Inter-carrier interference (ICI); Radius-aided maximum likelihood detection with QR decomposition and M-algorithm (QRM-MLD)
• ISSN: 0030-4018; 1873-0310
• DOI: 10.1016/j.optcom.2019.124742

In this paper, a radius-aided maximum likelihood detection with QR decomposition and M-algorithm (QRM-MLD) is proposed for inter-carrier interference (ICI) cancellation in a faster-than-Nyquist non-orthogonal frequency-division multiplexing (FTN-NOFDM) system. With almost the same ICI cancellation performance, the radius-aided QRM-MLD has lower computational complexity than the conventional QRM-MLD by predicting the search radius with the radius-predicted symbol. There is not any redundancy induced by radius-predicted symbol because the transmitted data also can be obtained from it. In order to validate the proposed algorithm in the experiment, the 28-Gb/s FTN-NOFDM signal was transmitted through a bandwidth-limited experimental system, and the radius-aided QRM-MLD is applied for ICI cancellation. In this bandwidth-limited system, the 3-dB equivalent bandwidth is only approximately 5.5 GHz. The experimental results reveal that the bandwidth-compressed FTN-NOFDM with radius-aided QRM-MLD has better bit error rate performance than orthogonal frequency-division multiplexing, which shows the superiority of the proposed scheme in bandwidth-limited systems.