Bluetooth
Bluetooth standard has been promoted by the Bluetooth SIG, a private non-profit association founded in 1998 by Ericsson, IBM, Intel, Toshiba and Nokia, with more than 14,000 companies nowadays. The group is focused on publishing Bluetooth specifications, managing the compatibility program and promoting technology.
The most typical Bluetooth application is the hands-free mobile phone kit in a car. However there are many other applications where Bluetooth replaces the wires, e.g. remote controls on consoles, earphones and other medical devices, for data transmission at sensors in industrial automation, etc...
TST Products & Services
TST has deep knowledge of Bluetooth technology. We offer consulting services, Bluetooth communication in the TSmarT platform, and proximity marketing applications based on this technology.
TST Projects
TST has provided network design services, technical support, maintenance, campaign management and J2ME apps for cellular phones in a proximity marketing project for the Santander City Council.
Technology
The Bluetooth standard is based on IEEE 802.15.1 protocol. Bluetooth works at 2,4 GHz, a free ISM band, making use of spread spectrum modulation along with frequency hopping (1.600 frequency channel changes per second) in a full-duplex mode. Bluetooth has 79 channels with a bandwidth of 1MHz each one.
The coverage varies according to transmitter:Class 3: Up to 1 meter (@ 1 mW).
Class 2: Up to 10 meters (@ 2.5 mW).
Class 1: Up to 100 meters (@ 100 mW).
In theory a bitrate of 706,25 kbps can be reached in reception and 57,6 kbps in transmission. From version 2.0 + EDR bitrate triples, i.e. 2,1 Mbps. A Bluetooth device (from version 1.1) can support up to 7 simultaneous sessions with other devices, although they have to share the available bandwidth.
A Bluetooth piconet encompasses up to 255 devices, 8 can be simultaneously active. The others 247 devices maintain synchronization with the piconet and can be activated on demand. One of the 8 active devices behaves as master and the rest as slaves. The master manages the communication and assigns slaves temporal slots to transmit (TDMA access). A Bluetooth device can be registered in various piconets simultaneously, but only can act as master in one of them. A scatternet can have up to 10 piconets, so Bluetooth devices from one piconet can communicate with other devices of another piconet in the same scatternet, although throughput falls down drastically. Each piconet is identified by a different sequence of frequency hopping.
