> If 5G uses almost the same frequency where microwaves detect water vapour (around 24 GHz), won't the weather have a great impact on it?
There's a general misunderstanding about the technology that leads people down this road of thought.
5G is broken up into two frequency ranges, FR1 and FR2. FR1 is everything below 6Ghz and encompasses the same spectrum as traditional cellular technologies. FR2 is everything over 24Ghz and that's the bit everyone is confused about.
FR1 is like traditional cellular and will be slapped on cell towers to provide broad coverage over a wide area with performance characteristics similar to what we have today with LTE. It's not very exciting but it's 5G and this is what everyone is currently rolling out.
FR2 is meant to be absorbed, otherwise you'd have a big problem. Unlike FR1 which limits you to 100mhz bandwidth per channel, FR2 mandates that channel bandwidth be between 50-400mhz. So at a minimum, an FR2 channel will have half the maximum allowable bandwidth of FR1. If FR2 propagated more than a very short distance the airwaves would be quickly saturated by a small number of users.
FR2 is intended to be deployed in very dense areas like indoors. You'd be able to deploy many cell sites without worrying about overlap or signal propagation because everything from walls to moisture in the air will absorb the signals.
It might also be possible to slap an FR2 cell site on top of every lamp post going down a street.
Wouldn't there be a great deal of contention with an FR2 on each lamp post; how would they avoid that? Are these cell sites meshing internally to create a backhaul, or is the idea that each lamp post is wired?
Why? The sites backhauls could be wires or wireless, it doesn't matter much as the backhaul is independent of the interface tranceiver. The sites interface would be attenuated for the short ranges. We can do this today with Wifi, every always thinks more power is better but sometimes less is more.
Samsung's 28Ghz solution was rated at something like 1500ft at maximum power. So one per city block might be more realistic than one per lamp post but it will ultimately come down to capacity. The mmWave portion of 5G is designed to high density deployments.
The problem is that omnidirectional (so non-directional) radiation causes the problem, not fixed point-to-point links. So, with the omnis the best idea is to limit their TX power and spread the noise via ultra-wide band multiplexing (using random orthogonal coding [which is CDMA or lately frequencies (subcarriers/subbands), which is OFDMA] minimizes the interference), but with the p2p links, you can go wild, use a relatively high power high frequency narrow band high symbol/baud modulation (like QAM256 - used in 802.11ac wifi).
But of course cables rule, because they are really great at containing the EM radiation. And lamps already have cables to power the lamp, and the micro-nano-pico-cell thingie will also need power too, and then you can just do Power over Ethernet and be done with it, and then concentrate the copper wires and switch to fiber.
Though probably the p2p mesh backhaul module would be pricey, but sometimes getting your cable to a switch is equally problematic/costly, so that's why probably a bit of both from a cost perspective too.
There's a general misunderstanding about the technology that leads people down this road of thought.
5G is broken up into two frequency ranges, FR1 and FR2. FR1 is everything below 6Ghz and encompasses the same spectrum as traditional cellular technologies. FR2 is everything over 24Ghz and that's the bit everyone is confused about.
FR1 is like traditional cellular and will be slapped on cell towers to provide broad coverage over a wide area with performance characteristics similar to what we have today with LTE. It's not very exciting but it's 5G and this is what everyone is currently rolling out.
FR2 is meant to be absorbed, otherwise you'd have a big problem. Unlike FR1 which limits you to 100mhz bandwidth per channel, FR2 mandates that channel bandwidth be between 50-400mhz. So at a minimum, an FR2 channel will have half the maximum allowable bandwidth of FR1. If FR2 propagated more than a very short distance the airwaves would be quickly saturated by a small number of users.
FR2 is intended to be deployed in very dense areas like indoors. You'd be able to deploy many cell sites without worrying about overlap or signal propagation because everything from walls to moisture in the air will absorb the signals.
It might also be possible to slap an FR2 cell site on top of every lamp post going down a street.