Today, broadband is an indispensable part of daily life for many people. There are two broadband options: wireline and wireless and both have their advantages. The choice for the consumer depends largely on the quality of the service that each can deliver for the specific application.
Wireline broadband consists of optical fiber and typically provides higher bandwidth than wireless. However, it is not available everywhere. Wireless broadband is available almost everywhere, but bandwidth can be a constraint. Ideally, a combination of an optical wireline and wireless network is the best option.
That’s where the fiber-wireless network, or FiWi, comes in to picture. As far as wireless broadband/mobile networks are concerned, the growth in data transmission can be achieved if the core of the network uses fixed-line optical fiber. For the evolution towards 5G, it is envisioned that optical-wireless FiWi networks will make a remarkable difference.
Let’s take a step back to review both fiber optics and wireless technology.
Optical fiber communications
- With fiber-optic communications, data is transmitted through a fiber-optic cable by turning the electrical signals to light-an electromagnetic wave-making the signal speed much faster than wired networks.
- Optical fibers are made of thin glass-like structures about the size of human hair used in long distance telecommunications due to their higher capacity and lower interference.
- The applications of fiber optics include telephone networks, CATV, Gigabit Ethernet, avionics and much more.
- In most wireless communication systems, data is transmitted in the form of radio waves.
- The network typically consists of radio transmitters and receivers that use radio waves to transmit and receive information without a wire over both short and long distances.
- Wireless applications include mobiles phones, data communications using Wi-Fi, wireless sensor networks, satellite communications and more.
Fiber-Wireless Networks and Convergence
Fi-Wi is the upcoming telecommunications technology. It is a combination of both optical networks (wired fiber-optic cables) and wireless networks (radio waves) that provide reliable telecommunication services across geographically distant areas.
A FiWi network consists of optical fiber at the back-end and wireless sub-networks at the front end that delivers millimeter wave (20 to 60 GHz) wireless service. It supports high-bandwidth, long-distance optical communications and flexible-omnipresent wireless communications.
There are two basic underlying technologies used in FiWi networks:
- Radio and fiber (R&F)
- Radio over fiber (ROF)
The fiber part of R&F is usually made up of Passive Optical Networks (PONs). PONs implement a point-to-multipoint architecture, a single optical fiber that serves multiple end points. The architecture consists of an Optical Line Termination (OLT) and Optical Network Units (ONUs) in the back-end. The wireless front-end of the FiWi network consists of wireless routers that typically use Wi-Fi and Wi-Max. This enables WLAN-based FiWi networks to offer extended coverage. The figure below depicts the typical architecture of a FiWi network.
A typical Fi-Wi network
The other primary underlying technology in FiWi networks is radio over fiber (ROF). Here, the light is modulated by the radio-frequency signal that is sent through the optical fiber cable. ROF offers transparency against the modulation techniques used and supports various digital and wireless standards.
Fiber has become a critical component in the next generation of wireless as data traffic travels at the speed of light in optical-fiber networks.
Future 5G wireless systems will need to support high data rates, and will not tolerate latency. Hence, the convergence of fiber-wireless networking will play a vital role in 5G wireless network densification allowing for a significant increase in the volume of mobile data, a broader array of connected devices and the growth in machine-to-machine transactions, all with lower latency and attenuation.
The wireless-optical-wireless mode established by FiWi networks will:
- Provide interference-free communications
- Allow very wide bandwidth supporting data rates of up to 10 Gbps
- Support various types of communication such as upstream, downstream and P2P communication
- On the downside, FiWi networks are more energy intensive, which needs to be addressed as more and more companies are reducing their carbon footprints as part of their corporate social responsibility commitments.
In the last few years, significant progress has been made in FiWi network architectural design, and the number of FiWi networks is on the rise around the world. There is ongoing research to resolve architectural issues, maximize network throughput and link FiWi with smart grid and cloud infrastructure.
With the advent of FiWi networks, the creation of long-distance, high-bandwidth and flexible communications has become possible as wireless technology hurdles towards a 5G future.
- “Fiber-Wireless Convergence in Next-Generation Communication Networks” by Ornatore, Massimo, Chang, Gee-Kung, Ellinas, Georgios (Eds.)
- “Optical Fiber Communication” by Gerd Keiser, 4th edition.