lower power small cells are better than repeaters in the tunnels. what commuters at underground stations need are more micro and pico cell splits, resource blocks, and available active sessions with tcp end points between mobile clients and a high availability server stack of gateways with big pipes to the internet.
can lah. these are either distributed antenna systems (das) or cloud/centralized-ran (c-ran) with small remote radio heads fed by fiber to a baseband hub in an equipment room in the station. one rack of baseband units can easily connect 96 remote radio heads distributed across the station and nearby tunnels. with multiple bands, e.g. quad-band, a single rrh can simultaneously serve 696 users in a single sector. a 96-integrated radio antenna system can serve 6,969 users simultaneously. with 3 telcos offering the same coverage and capacity footprint, that number can go up 3-fold. with stat muxing, oversubscription, self-optimizing network, and intelligent schedulers, that number can go 6.9-fold. it will help if smrt as a 4th telco operator builds a high capacity wi-fi network across all stations and tracks. many users can offload onto the wi-fi network, relieving the mobile telcos with the surge in demand for 4g resource blocks. japan, sk, china and u.s. already testing with fd-mimo with 64 antenna elements per radio head for 4g and 256 antenna elements per radio for 5g. is sg there yet?
