Busy Period Analysis of a Queueing System with Breakdowns and Its Application to Wireless Network Under Licensed Shared Access Regime

Licensed shared access (LSA) framework is becoming one of the promising trends for future 5G wireless networks. Two main parties are involved in the process of sharing the frequency band – the primarily user (owner) and the secondary user (licensee). From the LSA licensee’s perspective, who has access to the band when the owner does not need it, the band is unreliable and its customers (e.g. users of wireless network) suffer from possible service interruptions. This can only occur when there is at least one customer in service (i.e. in busy period). The aim of this paper is to estimate the impact of the LSA band unreliability to the LSA licensee within the period when some interruptions are possible. The metric is the relation between the number of service interruptions and the number of customers served during a busy period. We model the occupancy of the LSA band as a multi-server homogeneous queueing system with finite and infinite buffer size and deal with the busy period analysis. The system is analyzed in steady state by deriving expressions in terms of the Laplace-Stiltjes transforms for the continuous time distributions and in terms of the probability generating functions for the number of customers served during a busy period and number of failures which occur in a busy period. The non-monotonic nature of some probabilistic measures is identified. Some illustrative examples are added to the paper.