A few notes about 5G and similar high capacity cellular networks:
- The claimed throughput / user is about 1000 times larger than the 1G and 2G speech only cellular networks.
- The total available spectrum is always limited, so spectral efficiency is critical. There are also other radio spectrum users.
- With a huge number of users especially in densely populated areas means that the cell size must be very small, so that the same frequency can be reused at an other close by base stations.
- Especially with shorter microwave wavelengths, the capture area of a dipole receiver antenna becomes quite small and thus it is incapable of collecting a lot of signal power. A directional antenna solves this problem, but a paraboloid at a mobile phone is not very practical-), but some electronically steerable mobile phone antennas would help.
IMHO the last two points means that you need to put a base station (access point) in every (or at every other) lamp post in densely populated urban areas. This means that such access points must be cheap.
The problem is how to connect such base stations to each other and to the land line Internet (fiber). Most people seem to suggest some mesh based networks (either between base stations or satellites), but this will choke when more than a few networking (forwarding) nodes are involved in a path. While AC power is available at the light pole, fibers would also be needed to be installed to light poles to support the communication.