Advanced digital communications system design considerations for law enforcement and internal security purposes

Abstract

In the United States and worldwide, enciphered digital wireless systems are on the verge of proliferation as the Associated Public Safety Communications Officials (APCO) Project 25 advanced narrowband digital communications (ANDC) standards for law enforcement are finalized. Likewise, in Europe, the TETRA digital standards will likely accelerate deployment of digital wireless systems throughout the Continent. Both APCO Project 25 FDMA and TETRA TDMA system architectures are intended to support infrastructure dependent public safety and internal security "dispatch" operations whilst APCO Project 25 is more amenable to non-infrastructure based communications. We address the system features now available in first generation ANDC systems. In addition, we make recommendations appertaining to the design, modeling and simulation parameters applicable to both enciphered and unprotected digital tactical wireless communications architectures suitable for law enforcement and internal security purposes. As we move into the digital world, is should be noted that the performance of enciphered digital wireless systems are severely impacted not only by the magnitude of the recovered radio frequency signal but more so by the phase perturbations typically encountered in tactical wireless environments. Thus, enciphered digital wireless system design, modeling and simulation must be multi-dimensional, recognizing and overcoming those environmental aspects which most significantly affect its viability.