The number of concurrent radio conversations possible in a given area has doubled roughly every 30 months since 1895.
Cooper's law has held across spark-gap telegraphy, broadcast radio, and cellular networks — the underlying gain comes mainly from spatial reuse rather than from spectrum or coding.
In practice
- A stadium that could not run a hundred phones in 2005 runs sixty thousand in 2020 on the same allocation of spectrum.
- A city's mobile network absorbs a decade of traffic growth by putting more, smaller cells on more lampposts.