The ZigBee network uses license-free ISM bands for transmission and can therefore be operated license-free. In Europe, it is the ISM band around 868 MHz that is used by various other technologies such as that for Short Range Devices (SRD), RFID, Wibree and other services. Worldwide, ZigBee uses the frequency range of 2.4 GHz
and in the United States the ISM range around 915 MHz. As for the ISM band used worldwide at 2.4 GHz, the frequency band
isbetween 2.405 GHz and 2.480 GHz. This frequency band is used by various short-range wireless technologies
igBeeIn ZigBee, the 2.4 GHz frequency band is divided into 16 channels with a channel spacing of 5 MHz. On each of the sixteen channels, the data transmission rate is 250 kbit/s. The frequency bands used in Europe are 433 MHz and 868 MHz. The higher frequency band is between 868 MHz and 870 MHz and has only one channel on which data can be transmitted with a data rate of
only 20 kbit/s. The frequency band used in the USA has a channel grid of 5 MHz. The frequency band used in the USA between 902 MHz to 920 MHz is divided into ten channels with a channel width of 2 MHz.
keyingand spread spectrum technology
tobetter protect the transmission against interference, or with Offset Quadrature Phase Shift Keying
(OQPSK) to achieve higher data rates. The range of ZigBee is between 10 m and 75 m, depending on the transmission power.