Improving Public Safety Wireless Communications: Analyzing the Cost of a Nationwide Network and Strategies for Sharing Commercial Networks.

摘要

The existing U.S. public safety wireless infrastructure consists of thousands of disparate systems built by separate local agencies. Problems with interoperability, cost, spectral efficiency, and limited functionality plague these systems. This dissertation analyzes a number of proposals for improving public safety wireless communications, particularly in the U.S., through the deployment of broadband wireless networks. This dissertation is broken up into three main parts. The first part develops a model to quantify the costs of a nationwide broadband wireless network that serves public safety users, and applies that model to several different network approaches. The second part extends the model to analyze the cost and revenue of a network that serves both public safety and commercial users on the same infrastructure and spectrum. The third part analyzes the potential for commercial broadband networks to supplement dedicated public safety networks, studying the technical and operational design decisions associated with enabling priority roaming access, and options for compensating commercial carriers for this roaming access.;Among the results, in Part I it's demonstrated that the nation's many small systems could be replaced with a single nationwide network with a small fraction of the tower sites and spectrum, and at a cost comparable to what is spent in just a few years on the existing infrastructure. It is shown that these cost estimates are highly dependent on some key system design parameters including public safety capacity requirements and signal coverage reliability. In Part II, it's found that the value of the extra 10 MHz of spectrum used in a public-private partnership exceeds the cost of meeting public safety requirements. Furthermore, it is demonstrated that the profitability of the partnership increases with population density, so urban areas are profitable and rural areas are unprofitable. In Part III, it is shown that LTE offers a wide range of priority-related capabilities that could be important for making roaming valuable to public safety users. Finally, it is shown that there are significant financial benefits associated with public safety roaming on commercial networks, and some risks, which can in part be mitigated by the choice of pricing scheme.