The upcoming auction of the very-desirable 700-MHz. spectrum by the FCC creates an important and in fact unique opportunity to rethink a number of key assumptions about both spectrum policy and the nature of wireless network architectures. We expect the demand for the various bands at 700 MHz. to be very heavy primarily because the radio propagation characteristics of these frequencies allow excellent coverage in urban, suburban, and rural areas, and even indoors as well. Both commercial and government interests are excited about the possibilities here, and that brings up an interesting question indeed: is it feasible to deploy a single network infrastructure in this spectrum, based on a common architecture, which can serve the needs of both of these constituencies?
Traditionally, licensed spectrum has been reserved for individual licensees. This has always been the case of government -- primarily public safety and emergency/first-responder services -- because, well, that's the way it's always been, and, of course, the nature of the fundamentally analog communications historically used in public-safety applications is poorly suited to any form of spectrum sharing. But modern, digital networking and communications technologies, primarily in the form of an all-Internet Protocol (IP), mobile, wireless, broadband network with full support for prioritized and time-bounded traffic, instead constitute an ideal platform for a shared-access networks meeting the needs of perhaps many simultaneous and distinct services, constituencies, and applications -- public-sector and commercial alike. Note here that we are talking about network architecture based on IP, but not about any specific radio technology. One of the core benefits of this approach is that it is in fact entirely independent of any specific radio implementation, and, in fact, could work well with a multi-radio converged strategy -- another trend that we believe will become essential in future wireless networks.
The purpose of this Tech Note is to explore the key elements of shared-access wireless networks, and why this strategy will become the preferred -- if not dominant -- approach in future network deployments, both public-safety and commercial, at any frequency, and particularly in the 700 MHz. bands.
Understanding shared-access networks
IP has become, over the past 20 years, the only network protocol that matters. Part of the reason for this is of course the success of the Internet, but also the fact that the IP protocol stack has benefited from continual improvements and additions to support essentially any class of service, from low-bandwidth, high-latency traffic to quite the opposite, broadband, telephony and streaming video. One could argue, of course that they key to success for the Internet was a fundamentally cooperative implementation essentially based on the concept of over-provisioning. With the supply of bandwidth exceeding demand, there's less need for clever protocol-based solutions implementing quality of service (QoS) and class of service (CoS) capabilities. But these protocols have nonetheless appeared in IP over the years, making it suitable to essentially any type of traffic and supporting essentially any network-based application. Both raw bandwidth and the management of this bandwidth via protocols will continue to be core requirements, especially as networks see more traffic and occasionally become congested...
To read the full report, download this PDF: Optimizing spectrum utilization: The shared-access network
About the author:
Craig Mathias is a principal with Farpoint Group, an advisory firm based in Ashland, Mass., specializing in wireless networking and mobile computing. The firm works with manufacturers, enterprises, carriers, government, and the financial community on all aspects of wireless and mobile. He can be reached at firstname.lastname@example.org.