Research

Today, the design of microwave backhaul relies on Clear Line of Sight (CLOS) 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. To address this challenge, we explore the use of diffraction, a physics phenomenon through which some wireless signal energy is bent into the geometric shadow of the obstacle. We show that when diffraction could be predicted reliably, it could be used to design and build wireless Non- Line of Sight (NLOS) backhaul links in challenging environments, reducing the need to build repeaters and making network design more efficient. We present a feasible condition for the use of diffractive NLOS, for a single obstacle with shallow diffraction angle, modest foliage loss, and moderate foliage, which we call NLOSv1. This solution can be implemented using standard microwave backhaul radio and link design / network planning software. Through a design-study example, we show there is significant beneficial contribution to network design and implementation in rural/deep-rural networks. This solution has been implemented by Internet para Todos (IpT) and Mayutel in commercial, carrier-grade networks in Peru.