Eastern dreams

摘要

During the 1990s, I was the technical lead on aproject to design a transmitter controller using radio pagers. The original pagers were receive-only devices. To get messages to the pagers, the systems would transmit the same signal—on the same frequency channel—on every transmitter of the pager's contracted coverage area. This area was sometimes a large part of the United States, requiring more than several thousand transmitters. Due to directional diversity and, in signal-overlap areas, power summation, using this many transmitters provided better area and building-penetration coverage than do today's cell phones.