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Top1. Introduction
Cellular network is a radio network distributed over areas called cells, each cell served by at least one transceiver known as base station. Each base station is associated with certain number of channels which are responsible for communication. One of the most important features of cellular communication system is mobility. Mobility is implemented by call handoff from existing cell to new cell when the user moves to new area when the call is in progress. The procedure of changing channel is part of “handover/handoff”. A user can tolerate dropping of a new call but cannot tolerate dropping of an ongoing call. Therefore priority is given to handoff calls while assigning channels to new calls. Various prioritization schemes are discussed in (Re, E., Fantacci, R., & Giambene, G. 1999; Zheng, ZH; Lam, WH 2002; Hong & Rappaport 1986; Tekinay & Jabbari 1992; Ebersman & Tonguz 1999; Xhafa & Tonguz 2004; Ariton E. Xhafa & Ozan K. Tonguz 2008).
While assigning channels two types of calls compete for resource allocation one is handoff call and the other is new call or originating call (I. Katzela & M. Naghshineh 1996). There is another type of call which requires highest priority while assigning channels i.e. emergency call. Emergency calls are those which are found during emergency situations like road mishaps, fire accidents, natural disasters, terrorist attacks etc (Manali Joshi & Ajaay Mansata 2005). In such areas demand for communication becomes high; as a result more number of emergency calls are made. These calls are considered important because such calls may help in saving many lives during emergency. Emergency calls can also be found in telemedicine and Mobile healthcare environment (Lu Qiao & Polychronis Koutsakis 2011) where patients are provided health care services at understaffed areas such as rural health centers, ships, trains and airplanes. Therefore, these emergency calls should be given highest priority when compared to other calls. Public cellular networks are used to fulfill the high communication demand during emergency situations.
The existing channel assignment and prioritization schemes not discussed much about considering high priority for emergency calls. In contrast, this paper presents a new scheme called probabilistic emergency prioritization scheme (PEPS) where highest priority is given to emergency calls.
The rest of the paper is organized as follows: Section 2 discusses the survey of related work, section 3 presents the description of the proposed scheme, section 4 gives simulation and results and finally section 5 presents the conclusion.