The Effect of Re-dialing in a Personal Communications Services Network

This paper studies the eeect of re-dial in a personal communications services (PCS) network. The re-dialing problem for PCS is diierent from the plain old telephone service (POTS). When using POTS, if a customer receives a busy signal in making a call, or the call does connect in a timely manner, the customer may make a re-dial call in an attempt to get a connection. Likewise, it is anticipated personal communications services (PCS) network subscribers may also make re-dial attempts when the original call attempt is unsuccessful. However, unlike POTS, PCS has the added complexity of keeping a call connected while the originating caller and/or the terminating caller is moving. Because of this complexity, the eeect of re-dial on nomadic communications is a challenging problem that has implications on the design and analysis of PCS networks. Accordingly, this paper presents a model for studying the eeect of re-dial on PCS networks. Using this model, several analytical results are derived. These results are then used to validate a Time Warp based, distributed, simulation of the PCS re-dial model. Using the distributed simulation, we vary (i) the probability of re-dial, (ii) the re-dial rate, and (iii) portable mobility and examined each parameters eeect on (a) the probability of forced termination, (b) the probability of new call block (c) the call incompletion probability (d) expected number of re-dials before a new call attempt is accepted or rejected and (e) calls accepted per simulated second.