First generation: Cellular networks

The technological development that distinguished the First Generation mobile phones from the previous generation was the use of multiple cell sites,
and the ability to transfer calls from one site to the next as the user travelled between cells during a conversation.
The first commercially automated cellular network (the 1G generation) was launched in Japan by NTT in 1979.
The initial launch network covered the full metropolitan area of Tokyo's over 20 million inhabitants with a cellular network of 23 base stations.
Within five years, the NTT network had been expanded to cover the whole population of Japan and became the first nation-wide 1G network.
The technology in these early networks was pushed to the limit to accommodate increasing usage.
The base stations and the mobile phones utilised variable transmission power, which allowed range and cell size to vary.
As the system expanded and neared capacity, the ability to reduce transmission power allowed new cells to be added, resulting
in more, smaller cells and thus more capacity. The evidence of this growth can still be seen in the many older, tall cell site
towers with no antennae on the upper parts of their towers. These sites originally created large cells, and so had their antennae
mounted atop high towers; the towers were designed so that as the system expanded—and cell sizes shrank—the antennae could be lowered
on their original masts to reduce range.