remain. The cost of wireless voice systems needs to be reduced and their quality improved. Specialized wireless data networks have not taken off as yet, perhaps because they are not powerful enough or because mass market applications have yet to emerge. Considerable research to address these and other issues is under way, both in the United States and overseas. Industry road maps suggest that, by early in the twenty-first century, commercial wireless communications will meet the long-term goal of enabling users to communicate ''anytime, anywhere."
The DOD uses a variety of wireless systems that are based on 1970s and 1980s technology and designed to serve specific needs. The DOD no longer drives the evolution of state-of-the-art communications technology but still needs access to it, perhaps more than ever. As threats to peace change from global to regional conflict, a transformation is taking place in military roles, missions, and communications needs. The vision for military communications stresses C4I and the protection of the lives of U.S. personnel, who will be based principally in the United States but will need to be prepared to move quickly throughout the world to carry out a variety of missions, including noncombat roles such as peacekeeping and humanitarian response. Such missions are nontraditional in the sense that coordination with foreign partners may be essential, whereas national survival will not be at risk as was anticipated during the Cold War. In addition, the need for U.S.-based logistical support will grow, and new systems will be required to counter terrorism. Thus the accurate, timely transmission of information will be perhaps more essential than ever in meeting military objectives. Effective global communications systems will be critical.
The civilian and military sectors have a long history of interaction in the design and deployment of wireless communications technology. In the Gulf War, DOD used commercial wireless equipment such as GPS receivers and found that the performance was comparable to that of equipment designed explicitly to meet military needs. Yet current commercial technologies and practices cannot meet all military needs. For example, the military cannot tolerate the long lead timeson the order of months to yearsthat are typical in the building of commercial communications infrastructures. Commercial wireless companies carry out elaborate advance planning and measurement operations, whereas the military requires networks that can be organized quickly and can adapt rapidly to changing operating conditions (including spectrum availability). These networks will also have to be compatible with other military communications systems, both new and old.
Differences between military and commercial needs also have implications for network architecture. Commercial research on integrated (i.e., multimedia) systems is oriented toward network architectures based on the base-station-oriented model. It is not clear whether that approach or