An analysis of fixed wireless network interconnect costs

The total cost of the fixed infrastructure underlying a wireless network can be thought of as consisting of three elements: the costs of switching, interconnection of switching/control and radioports, and radioports. Historically, the interconnection cost has represented only 20% or less of the total investment in the network, the bulk of the cost being represented by switching and radio equipment. Consequently, optimizing the costs of the interconnection portion of the network has not received much interest. However, the economics of these networks are changing. PCS technology and dense user populations in cellular systems are requiring the use of more radioports, located more closely to one another than has previously been common, and technologies for extending the number of subscribers and/or radioports that may be controlled from a single base station controller (BSC) are reducing the relative costs of those segments of cost, thus making the cost of interconnect a larger percentage of the total than has heretofore been customary. It therefore follows that methods for analyzing and optimizing the cost of the interconnection segment may now be useful. This paper presents a model for the cost of the interconnection of the elements of a wireless network, and demonstrates that there exists a single optimum location for the control center in such a network. We develop a methodology for analyzing and optimizing interconnect costs, exploiting the characteristics of the cost function, which is shown to be convex. The results are general, and are not restricted to any particular form of cellular network