Searching for 3-6 m Range RFID or similar system

Hello, I am working on an art installation where the visitors will be tracked and part of the installation. They will carry something like a tag which will be recognized at multiple locations in the exhibition space.

I found out that I could use a RFID - based system.

Can you recommend me something specific? The readers have identify the tags in a 3 to 5 meter radius.

Or is there another system which I could use instead of RFID?

Thanks!

For 5m range your looking for something like this

I think DSRC is a little overkill, because I do not want to communicate between devices, I only want to check if some device is in the "trigger zone" of a reader/sensor.

RFID is a near-field technology - you appear to require a far field technology.

Near field requires a sensor of the same sort of size as the detection distance, here many metres.

A large near-field detector would have to be carefully designed to not be a risk to pace-makers, BTW.

I have never used it so see SparkFun or ThingMagic for details.

Thank you for your answers, i am now sticking to ble /ibeacon