Optimal LAP Altitude for Maximum Coverage

Low-altitude aerial platforms (LAPs) have recently gained significant popularity as key enablers for rapid deployable relief networks where coverage is provided by onboard radio heads. These platforms are capable of delivering essential wireless communication for public safety agencies in remote areas or during the aftermath of natural disasters. In this letter, we present an analytical approach to optimizing the altitude of such platforms to provide maximum radio coverage on the ground. Our analysis shows that the optimal altitude is a function of the maximum allowed pathloss and of the statistical parameters of the urban environment, as defined by the International Telecommunication Union. Furthermore, we present a closed-form formula for predicting the probability of the geometrical line of sight between a LAP and a ground receiver.

I. Introduction

BROADBAND wireless networks are increasingly adopted by users of mission critical communications, such as public safety agencies and first responders. This adoption is motivated by the unprecedented development in these networks in terms of capacity and efficiency, compared to the legacy (second generation) mobile communication systems. However, as any cellular network, the communication is largely dependent on fixed infrastructure (base stations) that could be severally disrupted in the case of natural disasters such as floods, earthquakes or tsunamis. By which, inducing the need for finding a rapid and cost-effective temporary recovery solution an utmost necessity. One of the prospective feasible solutions for realizing wireless recovery networks is by utilizing airborne base stations. The airborne communication infrastructure concept has been endorsed by the homeland security bureau in USA [1]. An example of the recent efforts in airborne network recovery solutions is the ongoing European Commission project ABSOLUTE [2] focusing on Low Altitude Platforms (LAP).