Bluetooth is a low-power wireless networking technology operating in the 2.4 GHz unlicensed Industrial, Scientific and Medical (ISM) band. There are two classes of Bluetooth device — Class 1 devices have higher output power and a range of about 100 meters, and Class 2 devices have lower power and a range of about 10 meters. Bluetooth enables ad hoc networking of up to eight devices (supporting voice and data). The Bluetooth Special Interest Group (SIG) was founded in 1998 by IBM, Intel, Ericsson, Nokia and Toshiba, and is supported by more than 2,500 organizations. The Bluetooth v.1.0 specification was ratified and published in 1999 and supported data rates of up to 1Mbps. Bluetooth Version 2.1, along with its enhanced data rate (EDR) specification, was ratified in March 2007, supporting data rates of up to 3 Mbps, and simplified “pairing” — the process used for securely linking one Bluetooth device to another. It also reduced power consumption, doubling the battery life of headsets and other mobile devices for which the Bluetooth radio consumes a large percentage of the power budget. Version 3.0 (“Seattle”) was adopted by the SIG in April 2009, and the specification included Wi-Fi as an alternative transport layer for large volumes of data, supporting data rates of up to 24 Mbps. The SIG also adopted “Bluetooth low energy,” a new ultra-low-power variant, previously referred to as Ultra Low Power (ULP) Bluetooth and Wibree.
Wi-Fi is a short-range wireless communication technology adopting the 802.11 wireless network standard. Most of the notebook computers, mobile phones or mobile Internet devices nowadays are able to support Wi-Fi wireless connection. The transmission speed of Wi-Fi can be up to 54 Mbps, while its communication range can reach 305 meters with high stability and reliability. At present, many coffee shops, shopping malls, hotels and airports offer chargeable or free-of-charge Wi-Fi wireless broadband. The service is also available on some public transport.