Connectivity study in professional mobile radio networks with portable 4G base stations

Professional Mobile Radio (PMR) is a niche market which has been recently revitalized. Since public safety officers are required to operate in challenging or extreme conditions, radio communication is an essential asset to enable them to communicate with one another and with command centers organizing operations. We focus on an advanced deployment in which connectivity is provided by a temporary aerial-terrestrial network made of aerial and terrestrial nodes to create 4G LTEA connectivity and to provision advanced data services in a geographical area of interest. In cases of scarce radio coverage of the aerial platforms, terrestrial nodes can conveniently act as relays to route traffic to/from the serving aerial base stations. We study connectivity and the service interruption time prior to reconnecting to a relay in a network consisting of 4G handhelds and relays. We study connectivity resorting to stochastic geometry, while modeling at the same time the amount of available resources at each relay node and radio signal propagation using the Okumura-Hata model for the urban environment. We will show that a region of space around a relay exists which allows us to optimize connectivity and minimize delay.