5th Generation mobile systems and devices are coming online today in several UK cities. The difference between 4G and 5G is mostly in the way the radio signals are dealt with and how they are modulated. For now 5G signals are using bandwidth in the same ballpark as 2/3&4 Gen signals do already. Although there are plans to use the 24/27GHz range in future. Because higher frequencies do not travel as far or penetrate walls so easily, more localised masts will be needed.
The ideal location for these masts is on Street lamps - high structures with power and cabling already attached. This big increase in the No. of cell sites has been the grounding for anti 5G campaigners who are rehashing the supposed dangers of radiation but subtly changing it to use terms like "weapons-grade tech" (the same frequency is used in weapons guidance systems) and scaremongering the public over nothing.
The truth is, the Electromagnetic Frequencies (EMF) planned for the roll out are still several orders of magnitude below any dangerous ionising radiation. The huge amount of radiation put out by the sun dwarfs any level we currently experience and study after study on millions of people around the world has failed to demonstrate any harm caused by EMFs when used within safety guidelines.