People in their cars, people in the street, people at work, people at home--communicating through their mobile phones. Wireless communication might be the trend of the nineties, and it definitely means big business for the telecommunication industry. In Germany, for example, every third phone sold today is mobile. In the US, there will soon be 20 million subscribers to cellular phone services. In the second half of the nineties, 20% to 30% of phones sold worldwide are expected to be wireless .

The introduction of a European standard for digital cordless telecommunication has made cordless local area networks possible. Mobile communication can come to company sites. No cabling is required, and the employees can be reached anytime at any place. However, planning wireless digital networks is quite different from planning traditional wire-based systems. The plan must account for the specifics of radio-wave propagation at the installation site. Computer-aided planning promises to ease some of the difficulties.

In this article, we describe Popular (Planning of Picocellular Radio), a prototype tool resulting from a collaboration of industry and research institutions in Germany: the Siemens Research and Development Department, the Siemens Personal Networks Department, the European Computer-Industry Research Center (ECRC), and the Institute of Communication Networks at the Aachen University of Technology. Popular uses a path-loss model to describe radio-wave transmission and constraint-based programming to optimize the placement of base stations (transmitters) for local wireless communication at company sites.