Full-duplex WDM-RoF system based on OFC with dual frequency microwave signal generation and wavelength reuse
Introduction
With the rapid increase of the mobile communication services, the spectrum resources of low frequency bands are becoming more and more crowded [1], [2], [3]. In order to solve this problem, attention is focused on the higher frequency microwave band due to its greater communication capacity and higher data transmission rate [4]. However, the propagation distance of high frequency microwave signals is greatly limited for wireless communication due to the fact that the high frequency microwave is subjected to high atmospheric attenuation and the poor diffraction [5], [6].
Radio over fiber (RoF) system combines the advantages of optical fiber communication and wireless communication to effectively solve limited coverage of high frequency microwaves signals [7], which has the advantages of low loss, wide bandwidth, long-distance transmission, strong anti-interference ability, low cost and easy maintenance. In order to further improve the communication capacity of the RoF system and reduce the construction cost, the WDM-RoF system is formed by combining the RoF system with the wavelength division multiplexing (WDM) technology. The WDM-RoF system can achieve seamless connection between wired and wireless networks, and meet the needs of high-speed, large-capacity in future mobile communication systems [8], [9].
In recent years, many WDM-RoF schemes have been investigated. Most of them only studied downlink communication and lacked the research on uplink communication [10], [11], [12], [13]. In some full-duplex WDM-ROF systems, multiple independent lasers serve as the optical carriers [14], [15], [16], which increases the cost and complexity of the system. A few schemes only generate single-frequency microwave signal in the base station [17], [18], which hardly meet the demands of base station in different occasions. A full-duplex broadcast RoF-WDM-PON with self-coherent detection and photonic frequency up/down-conversion was presented [19], in which base station cost is significantly increased and stability is reduced due to the complexity of the base station structure. A full-duplex WDM-RoF system based on tunable optical frequency comb generator was proposed [20], in which only 5 optical carriers are used among the numerous optical carriers in each base station, resulting in low spectral-efficiency of the whole system.
In this work, we propose a novel full-duplex WDM-RoF system based on optical frequency comb. For the convenience of research, we study the downlink of this scheme using broadcast communication instead of multi-channel modulation. The flat optical frequency combs generated by cascaded EAMs and FM are used as the optical carriers of the WDM-RoF system, so the complexity and cost of the system are greatly reduced. In addition, this WDM-RoF system with optical carrier reuse can realize the uplink transmission without any local optical sources in the base station. Meanwhile, dual frequency microwave signals are generated in the base station for wireless communication. The feasibility and transmission performance of our scheme are successfully verified by Optisystem software. This paper is organized as follows. Section 2 describes the principle and theoretical analysis of the proposed full-duplex WDM-RoF system. In section 3, the simulation results and performances of the full-duplex WDM-RoF system are discussed. Finally, the conclusions are presented in section 4.
Section snippets
Principle and theoretical analysis
Fig. 1 presents the schematic setup of the proposed full-duplex WDM-RoF system, which consists of three parts: central station (CS), remote node (RN) and base station (BS). In the CS, the optical carriers of WDM-RoF system are generated by a TOFC generator, which is composed of one continuous wave (CW) laser, RF source (RF1), phase shifter (PS1), two electro-absorption modulator (EAMs) and a frequency modulator (FM), as shown in Fig. 2. Here, the CW laser is used as the optical source of TOFC
Simulation results and discussion
In the simulations, the CW laser is operated at 193.1THz with an optical power of 20dBm and a linewidth of 10 MHz. The RF1 is a cosine signal with a frequency of 40 GHz. The PS1 is set at 90°. EAM1 and EAM2 are both at reversed bias with bias voltage of 1 V and modulation voltage of 2 V. Frequency offset of FM is 600 GHz. Fig. 3 shows the output optical spectra of FM and EAM2 in TOFC generator. From Fig. 3 (a), it can be seen that optical comb lines with frequency interval of 40 GHz and
Conclusions
We have proposed a novel full duplex WDM-RoF system based on OFC with dual frequency microwave signal generation and wavelength reuse. In TOFC generator, we employ two EAMs and a FM to generate optical carriers. The optical carriers can be flexibly adjusted according to the needs of the WDM-RoF system, which greatly reduces the cost of the optical source. Some of optical carriers are reused in the BS to provide optical source for uplink transmission, which avoids the use of lasers in the BS to
Conflict of interest statement
We declare that we have no financial and personal relationships with other people or organizations that can inappropriately influence our work, there is no professional or other personal interest of any nature or kind in any product, service and/or company that could be construed as influencing the position presented in, or the review of, the manuscript entitled, “Full-duplex WDM-RoF system based on OFC with dual frequency microwave signal generation and wavelength reuse”.
CRediT authorship contribution statement
Yang Liu: Conceptualization, Methodology, Software, Validation, Formal analysis, Investigation, Visualization, Writing - original draft, Writing - review & editing. Hui Gao: Data curation, Writing - review & editing. Ying Chen: Data curation, Writing - review & editing. Peili Li: Writing - review & editing, Supervision, Project administration, Funding acquisition.
Acknowledgments
This work is partly supported by the National Natural Science Foundation of China (Grant No. 61275067) and Postgraduate Research & Practice Innovation Program of Jiangsu Province (Grant No. KYCX18_0855).
References (22)
- et al.
Novel 60 GHz RoF system with optical single sideband mm-wave signal generation and wavelength reuse for uplink connection
Optics Commun.
(2012) - et al.
W-band RoF transmission based on optical multi-carrier generation by cascading one directly-modulated DFB laser and one phase modulator
Optics Commun.
(2015) - et al.
Scalable and reconfigurable generation of flat optical comb for WDM-based next-generation broadband optical access networks
Optics Commun.
(2014) - et al.
Multi-service radio-over-fiber system with multiple base-station groups enabled by scalable generation of multi-frequency MMWs
Optics Commun.
(2014) - et al.
Full-duplex RoF link with broadband mm-wave signal in W-band based on WDM-PON access network with optical mm-wave local oscillator broadcasting
Optics Commun.
(2015) - et al.
High-efficient full-duplex WDM-RoF system with sub-central station
Optics Commun.
(2018) - et al.
A full-duplex WDM-RoF system based on tunable optical frequency comb generator
Optics Commun.
(2015) - et al.
Realizing 5G: microwave photonics for 5G mobile wireless systems
IEEE Microwave Magazine
(2015) - et al.
Radio-over-fibre for ultra-small 5G cells
17th international conference on transparent optical networks (ICTON), 2015
(2015) - et al.
Alternative wired and 60-GHz wireless full duplex access based on a polarization orthogonal dual-tone optical millimeter-wave signal
Fiber Integ. Optics
(2015)
The requirements, challenges, and technologies for 5G of terrestrial mobile telecommunication
IEEE Commun. Mag.
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