Handling high number of concurrent GSM device connections How do telcos manage high concurrent GSM dial ins or dial outs? We are deploying thousands of remote, GSM enabled utility meters and have to manage too many GSM modems that the meters will dial in to. What is the better way of handling this?

Standard BTS (with 3 cells) can handle around 9 erlangs which is enough to support circa 1500 subscribers, but everything depends. All station are built to suit terrain and people density on given area. Is very difficult to say as you have not specified if those modems are 3G, GRPS or LTE. For example LTE with 2x20Mhz wide, 4x4Mimo and 64QAM could reach as much as Download ~300Mbps and ~80Mbps uplink. Not all modems have active connction all the time. Some connected send data some are in RRC-Idle. As well if there is mutliple devices they would share channel/bandwitch (stat-mux).

Edit: So you are using modems as gateway for each meter to dial in? I'm pretty suprised as this solution is not scalable. I would say that much better would be to access destination servers over IP from GSM provider network, rather than dial-in into dedicated gateways.