Abstract
Sub-terahertz (THz)-band communication system has drawn much attention as a promising technology to provide future-proof high data rate services. In a photonics-based sub-THz communication system, the generation of THz wave using free running lasers enables us to make a simple, cost effective and frequency tunable implementation. On the other hand, commercially available lasers have relatively broader linewidth and a large carrier frequency offset (CFO). To mitigate the performance degradations due to phase noise and CFO, a carrier recovery digital signal processing (DSP) algorithm is studied for a sub-THz transmission system. We propose a novel phase estimation algorithm to avoid cyclic slips while minimizing phase estimation error to improve BER performance. Our proposed phase recovery DSP algorithm is demonstrated in a 16-quadrature amplitude modulation (QAM) in a 0.3 THz band photonics-based transmission system. Experimental results show that the measured BER are improved from 8.8×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−3</sup> to 3.6×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−3</sup> in a 120 Gb/s 16-QAM transmission using the proposed algorithm. A wide range of CFO estimation is also supported for a sub-THz wireless transmission system using off-the-shelf lasers. Recovery of a CFO between −5 GHz and 5 GHz was also successfully demonstrated.
Highlights
The data rate of wireless communication has been increased to meet the ever-increasing demand for data traffic
Sub-THz communication is a promising technology for the generation wireless communication
A photonics-based sub-THz communication system suffer from severe phase noise and a large carrier frequency offset (CFO), especially when two free-running LDs are used for cost effectiveness
Summary
The data rate of wireless communication has been increased to meet the ever-increasing demand for data traffic. A phase noise and a wide range of carrier frequency offset (CFO) are the major impairments in a photonics-based sub-THz system using free running lasers [5]. A wide range of sub-THz frequency offset is generated due to the frequency drifts of two free running lasers To mitigate these effects, optical filtering of optical frequency comb generator was proposed, but it significantly increased the complexity of the transmitter [5]. The maximum likelihood (ML) algorithm or the phase-locked loop (PLL) combined with BPS were proposed [9, 10] These blind algorithms were vulnerable to the cyclic slip problem which comes from 4-fold phase estimation. In addition to phase noise, carrier recovery DSP for photonics-based sub-THz systems should have an ability to recover a wide range of CFO. A CFO estimation using a preamble is applied to provide a wide and accurate CFO estimation
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
