Multi-band, multi-mode, ultra-communications node for improved interoperability

This paper addresses advanced Software Radio architecture and technologies that promise to improve the communications aspect of the interoperability problem. Its intent is to inform the reader of technologies under development today that could provide the means to solve many of the issues that limit communications between agencies and jurisdictions of the Public Safety sector. It is not intended to address issues such as spectrum allocation or operational coordination. Basic elements of interoperability are addressed and basic definitions of the problem are provided. Issues such as multi-jurisdiction and multi-agency coordination are addressed. The issue of the wide range of frequencies allocated for Public Safety use is of particular importance. A Software Radio Architecture presentation follows with a discussion of the basic components and the benefits of this approach. The primary Software Radio benefit is the use of a single radio to provide communications on a number of different frequencies with different demodulation schemes. Unique approaches to radio frequency preselection, broad band signal down-conversion, high-speed digital sampling techniques, and multi channel signal processing are discussed. Enabling technologies will then be introduced, briefly covering Microelectromechanical Systems radio frequency devices, Silicon Germanium radio frequency application specific integrated circuits, advanced analog to digital converters, state-of-the-art digital signal processing, and vertical cavity, surface emitting lasers. The conclusion of the paper is that an advanced technology Software Radio is a viable, cost-effective solution for the interoperability problem in the Public Safety sector.