All deployment site photos from Peru were taken by our partners at Mayu Telecomunicaciones are used here with permission. To request permission to use the photos, contact firstname.lastname@example.org.
Facebook Connectivity’s mission is to enable better, broader global connectivity to bring more people online to a faster internet. We collaborate with others in the industry — including telecom operators, community leaders, technology developers, and researchers — in order to find solutions that are scalable and sustainable. One major research area of interest is rural connectivity, as many rural areas around the world still don’t have access to mobile connectivity and technology innovations are needed. An important element of rural connectivity is backhaul, the links that connect remote sites to the core network of the internet. Wireless backhaul using microwave radio provides low-cost, fast deployment in comparison with other options.
Today, the design of microwave backhaul relies on clear line-of-sight (LOS) requirements. Unfortunately, for rural areas, lack of LOS between settlements means that a repeater or reflector has to be built, which leads to cost constraints. In this project, we explore the use of diffraction, a physics phenomenon through which some wireless signal energy is bent into the geometric shadow of the obstacle. If diffraction can be predicted reliably, it could be used to design and build wireless backhaul links in challenging environments, reducing the need to build repeaters and making network design more efficient.
Example physics-based signal propagation modeling result showing that some signal energy is diffracted into the shadow region
Illustration of how diffractive NLOS wireless links can reduce the need to build repeaters
To address this challenge, Facebook Connectivity developed a research partnership with university and industry partners. We recognized that we need field data that can be used to validate and calibrate signal prediction algorithms, improved network design methodologies, and an assessment of real-world cost-coverage impact. To facilitate knowledge sharing and collaboration, Facebook Connectivity organized a number of meetings, including a workshop in 2019. In this workshop, Omar Tupayachi Calderon (CEO of Mayu Telecomunicaciones, a rural mobile infrastructure operator in Peru) shared that “Peru has an incredible diversity of challenges, and 60,000 rural settlements still do not have broadband connectivity. We need your help.”
Bringing rural connectivity to Peru
Universidad Politécnica de Madrid (UPM), The Ohio State University (OSU), Air Electronics, and Plexus Controls developed instruments to measure signal propagation over difficult terrain and conducted systematic experiments in southern Ohio, in areas near Madrid, Spain, and in southern Ontario, Canada. University of Michigan, George Mason University, OSU, and MIT developed propagation models, resulting in a number of publications and open source software.
Experimental data and setups used by OSU and UPM (click to enlarge)
The complete solution set that Facebook developed included an end-to-end workflow for link design, network planning, and site deployment, which we are sharing as a white paper in the Telecom Infra Project Network as a Service Solution project group.
Rural Peru deployment pictures taken by Mayutel (click to enlarge)
Scaling the solution
To make the solution usable in as many parts of the world as possible, Facebook took several next steps:
First, we collaborated with OSU and George Mason University to make a MATLAB and Python version of the Irregular Terrain Model and Longley-Rice algorithm available as free, open source software.
Second, we broadened the collaboration to include Contract Telecommunications LTD — the makers of Pathloss, the most widely used microwave link planning software in the world — to implement the outputs of this project into their platform.
Third, we developed a field-grade drone-mounted measurement kit with Plexus Controls to enable experimentalists to gather field data economically, and for connectivity infrastructure developers to validate signal strength in the field prior to building their sites. Further, we developed a software for data visualization and basic processing. The drone and the software are designed to enable faster, simpler field experiments and validation than ever before.
Fourth, we are contributing our learnings to the Telecom Infra Project Network as a Service Solution Group.
Finally, we have expanded our partnership through collaborations with TeleworX, Internet para Todos (IpT) de Peru, and Mayu Telecomunicaciones (Mayutel). IpT de Peru is a major network operator that is significantly expanding broadband access in rural parts of the country. Founded in 2019, IpT has deployed hundreds of broadband sites in rural areas of Peru to date. IpT has successfully deployed dozens of NLOS links in their network, providing both end point and backbone transport connectivity. Mayutel works with the local communities in rural Peru to build the telecom sites, deploy 4G radio systems, and provide broadband connectivity for the first time to many of the community.
As we look forward to bringing this solution to other parts of the world, please learn more about the technology behind this project through our publications:
- Diffractive NLOS Microwave Backhaul for Rural Connectivity
Julius Kusuma, Erik Boch, Philip Liddell (Facebook Connectivity)
- Development of Measurement and Modeling Procedures of Diffractive near-LOS Wireless Links
José Manuel Riera, Santiago Pérez-Peña, Marta Castiella-Fernández, Pedro Velasco-de-la-Fuente, Mateo Burgos-García, Pedro Garcia-del-Pino, Luis Mendo (Universidad Politécnica de Madrid, Spain), Julius Kusuma, Erik Boch (Facebook Connectivity)
- Gabor Frame-Based Sparsification and Radiation Boundary Conditions for Parabolic Wave Equations
Max Bright, Eric Michielssen (University of Michigan at Ann Arbor), Julius Kusuma (Facebook Connectivity)
- Hybrid Parabolic Equation – Integral Equation Solvers for Analyzing Long Range Propagation Over Complex Terrain
Eric Michielssen, Max Bright (University of Michigan at Ann Arbor), Julius Kusuma (Facebook Connectivity)
- Improving Rural Connectivity Coverage using Diffractive Non-Line of Sight (NLOS) Wireless Backhaul
Julius Kusuma, Erik Boch (Facebook Connectivity)
- itmlogic: The Irregular Terrain Model by Longley and Rice
Edward J. Oughton (University of Oxford; University of Cambridge), Tom Russell (University of Oxford), Joel Johnson (The Ohio State University), Caglar Yardim (The Ohio State University), and Julius Kusuma (Facebook Connectivity)
To learn about NLOS in the Telecom Infra Project Network-as-a-Service Solutions project group, please see our recently published white paper on the subject. For more about the Telecom Infra Project, visit their website. You can also learn about other initiatives on the Facebook Connectivity website.