ZigBee is a highly reliable wireless data transmission network, similar to CDMA and GSM networks. The ZigBee data transfer module is similar to a mobile network base station. Communication distance from the standard 75m to a few hundred meters, a few kilometers, and support unlimited expansion. ZigBee is a wireless data transmission network platform consisting of up to 65,000 wireless data transmission modules. Each ZigBee network data module can communicate with each other over the entire network. The distance between each network node can be changed from Standard 75m unlimited expansion.
① low power consumption. In the low power standby mode, two 5 batteries can support a node for 6 to 24 months, or even longer. This is the outstanding advantage of ZigBee. In contrast, Bluetooth can work for several weeks, WiFi can work for hours.
② low cost. By greatly simplifying the protocol (less than 1/10 of Bluetooth), the requirements for the communication controller are reduced. According to the predictive analysis, the full-function master node needs 32KB code with 8051 8-bit microcontrollers. To 4KB code, and ZigBee free protocol royalty. The price of each chip is about $ 2.
③ low rate. ZigBee operates at 20 to 250kbps, providing raw data throughput of 250 kbps (2.4GHz), 40kbps (915 MHz) and 20kbps (868 MHz), respectively, to meet the application requirements for low-rate data transmission.
④ close distance. Transmission range is generally between 10 ~ 100m, after increasing the transmit power, can also be increased to 1 ~ 3km. This refers to the distance between adjacent nodes. If the relay and the communication between the nodes through the relay, the transmission distance will be farther. ⑤ short delay. ZigBee response speed is faster, generally from sleep to work state only 15ms, the node connected to the network only 30ms, further saving power. In contrast, Bluetooth needs 3 ~ 10s, WiFi takes 3 s.
⑥ high capacity. ZigBee can use star, slice and mesh network structure, by a master node management of a number of sub-nodes, up to one master node can manage 254 sub-nodes; the same time the main node can also be managed by a network node, up to 65,000 Node of the big network.
⑦ high security. ZigBee provides three levels of security, including non-security settings, the use of access control lists (ACLs) to prevent illegal access to data and the use of advanced encryption standard (AES 128) symmetric password to flexibly determine its security attributes.
⑧ free license band. Using the Industrial Science Medical (ISM) band, 915 MHz (US), 868 MHz (Europe), 2. 4 GHz (global). Since the three physical bands are not the same, their respective channel bandwidths are different, respectively, 0.6MHz, 2MHz and 5MHz. There are 1, 10 and 16 channels respectively. The spread of these three bands and modulation methods are also different. Spread spectrum uses direct sequence spread spectrum (DSSS), but the difference from bit to chip is quite different. Modulation methods are used phase modulation technology, but the 868MHz and 915MHz band is used BPSK, and 2.4GHz band is used OQPSK. In the case of transmission power of 0dBm, Bluetooth can usually have a range of 10 meters. The ZigBee in the room can usually reach the role of 30-50 meters away in the open area can even reach 400 meters (TI CC2530 without power amplification). So ZigBee can be classified as low-speed short-range wireless communication technology.