Integrating secure communications into 800 MHz trunked systems

In recent years, there has been dramatic growth in the commercial market for 800 MHz trunking systems. This is due primarily to the degree of spectrum efficiency attainable and the availability of a variety of customer valued features. In addition, more and more federal, state, and local government agencies are seeking the benefits as well. While current trunking systems offer a level of speech privacy above that of conventional single channel systems, immunity from eavesdropping is often not great enough for certain government and special market users who demand totally secure speech encryption. This paper discusses various issues pertaining to how a secure speech capability can be provided on a trunking system. Topics covered include methods of digital speech encoding and encryption, approaches to integration of secure speech into the trunking system framework, and the effects of this integration on the trunking system's features and performance.