umm.. is wavelength the deciding factor? .. can Active RFID threat the current technologies?
"Wireless data networks are sprouting up like daisies. Wi-Fi hot spots have proliferated. Bluetooth personal-area networks are everywhere. And the push to make electric grids smarter is bringing with it a proliferation of ZigBee radios that use the airwaves to connect electric meters, lamps, light switches, thermostats, and appliances. So it might come as a surprise that yet another wireless-networking scheme, called Dash7, is entering the fray—and appears to be gaining traction. The International Organization for Standardization (ISO) first ratified the standard behind Dash7 in 2004, and it continues to be refined. Like Bluetooth and ZigBee, it's intended for low-power, low-bandwidth digital communications. But Dash7 hardware is designed to use even less power than other schemes, making it especially appropriate for such things as radio-frequency identification (RFID) tags, which must work for years without any external power source."
Read More: Dash7 Wireless Networking Gains Momentum - IEEE Spectrum