It's quite hilarious seeing bunch of skilled and intelligent hackers being excited regrading process known as "Handover" :) It is well known, and well documented in every single book in subject...
Worth to mention that there are 3 types of handovers:
- Intra-relations: user can be switched between various cells at same tower.
- Intra-relations but with handover to lower technology (let's say when 4g is not available[too much traffic], so you will be dropped to let's say 3g or even 2g cell)
- External-relations: relations between cells on different towers.
As for towers:
- Not all operators allows for local roaming between various operators.
- Most towers have 3-5 sectors (pizza slices), but it's not that unusual to see OMNI antennas(single sector for 360 degrees).