A technique we apply, and we know many other professionals use, is to establish a private microwave PtP Link from a location suitably outside of the area where the event is to be held back to the site, this may be a location where you have a connection to the ISP(s) be that physically or cellular/LTE.
@VideoStream has mentioned many points, here are some more to consider:
- LTE (or LTEA) Bandwidth is carrier capacity dependant around the world, in Australia we can get over 100Mbps upload and 200Mps download depending on where in the country we are. It varies dramatically between all three of the local carriers, area A may be better with carrier X and area B may be better with carrier Y.
- Any event that has fifteen thousand (15k) people coming to it is going to saturate the cellular/mobile facilities in the area and the backhaul in the area, therefore you need to get your own backhaul be that via Microwave PtP Link or leased fibre, depending on the type of data or location Satellite Broadband may also be an option. In a saturated cellular/mobile situation, even having a dozen SIM cards does not guarantee you bandwidth. @MartinLangmaid has written, as have others, about these many times before in the forum.
- The RF noise floor is going to substantially increase during any event, this is due to people mobile devices, other event related teams running their own RF equipment and transmissions from your own systems. The way we recommend handling this is through a combination of WAPs & managing the power levels. We often find more APs running on lower power levels and closer together handles this better than high powered APs spread far apparat.
- The MediaFast content caching can only be used for none secured data in a public Wi-Fi space due to the complexities around security certificates, so anything that is https or SSL cannot be cached (the majority of content people access day to day now is https & SSL such as all major social media & video platforms).
We use Peplink/Pepwave equipment complemented with many other reputable manufactures to help people pull off things like this, a supplied PtP may even have to be relay by one or multiple temporary solar powered locations and consist a mixture of licenced & unlicensed spectrum (depending on the project & environment).
Something that is important is to do a comprehensive site survey & design, with us this is not just of the event location, it includes the surround areas/towns/terrain and many other things. In Australia most of this can be incorporated into various GIS systems (including Google Earth Pro desktop version).
If you do not have someone who is capable of this locally, we can seek out through our other manufactures someone that may be suitably positioned to help you, just PM us if you need sort of assistance.
Happy to Help,