It has been a long haul for mobile services to gain sufficient capability and trust for widespread use in critical and emergency communications. For many years, consumers were advised to rely on fixed rather than mobile phones to call emergency services, while various dedicated critical wireless systems were used by those service themselves. The latter included Project 25 (P25 or APCO-25) adopted by public safety organizations in north America, and Tetra in Europe. These are both examples of land mobile radio systems (LMRS) for person-to-person communication, using frequencies reserved for these services, dating back long before the advent of cellular services in the 1980s. However, such services have failed to innovate and add the sort of features, such as support for video and even broadband data, that…