High Altitude Aeronautical Platform for VoIP: Dependability Analysis

VoIP has become a revolutionary technology in the field of communication as it provides long distant calls at a very low cost and has many other advantages. But it depends upon a reliable Internet connection with high bandwidth availability. To meet this requirement researchers have proposed the employment of VoIP over 5G network (Vo5G) which is expected to upgrade mobile broadband services in future. In this paper, we recommend integration of Vo5G with high altitude aeronautical platforms (HAAPs) which are used to decrease the distance of transmitted signals from the satellites. HAAPs are also used to extend the coverage and capacity of wireless communication. We propose an architecture in which voice services will be provided through a 5G network which is integrated with HAAP, i.e., Vo5G integrated with HAAP. A dependability model is developed using the key components of Vo5G and HAAP to analyze the dependability attributes of the proposed architecture. To analyze the dependability model we use a semi-Markov process (SMP), a generalized version of continuous time Markov chain (CTMC), which takes into account the non-Markovian behaviour of the time spent in different states of the system. The steady-state as well as the transient results for availability and reliability are obtained through the SMP model. The steady-state results are obtained analytically, whereas the transient results are obtained through simulation. A comparison is also presented between Vo5G integrated with HAAP and Vo5G without HAAP to show that the former performs better. Numerical results are presented graphically, and the proposed dependability model is also validated through discrete-event simulation.