ZigBee technology is a short-range, low complexity, low power consumption, low rate, low cost two-way wireless communication technology. It is mainly used for data transmission between various electronic devices with short distance, low power consumption and low transmission rate, as well as typical data transmission applications with periodic data, intermittent data and low response time. Since The invention of radio by Marconi, wireless communication technology has been evolving towards increasing data rates and distances.
ZigBee has the following characteristics:
(1) Low power consumption: Due to the short working time, low power consumption of sending and receiving information and the hibernation mode, ZigBee nodes are very power-saving. The battery working time of ZigBee nodes can be as long as 6 months to 2 years or even longer. This is ZigBee's outstanding advantage. Bluetooth, by contrast, works for weeks and WiFi for hours.
(2) Low cost: The initial cost of the module is estimated to be around $6, which could soon be reduced to $1.50-2.50, and the Zigbee protocol is patent-free. By greatly simplified protocol is very low cost (less than 1/10 of Bluetooth), reduce the requirements for communication controller, according to the forecast analysis, according to the 8051 8-bit microcontroller, the full function of the master node needs 32KB code, as little as 4KB code sub-function node, and ZigBee protocol patent is free;
(3) Low rate: ZigBee works at a communication rate of 250kbps to meet the application requirements of low rate data transmission;
(4) Short distance: the transmission range is generally between 10 and 100m, and can be increased to 1-3km after increasing RF transmitting power. This refers to the distance between adjacent nodes. If through the relay of routing and communication between nodes, the transmission distance can be further;
(5) Short delay: ZigBee has a fast response speed. Generally, it only takes 15ms to transfer from sleep to work, and only 30ms for nodes to connect to the network, which further saves electric energy. In comparison, Bluetooth requires 3-10s and WiFi requires 3s.
(6) High capacity: ZigBee can adopt star, sheet and mesh network structure. A master node can manage several child nodes. At most, a master node can manage 254 child nodes. At the same time, the primary node can also be managed by the upper-layer network nodes, which can form a maximum of 65,000 nodes.
(7) High security: Zigbee provides data integrity check and authentication functions, providing three-level security in data transmission, including no security Settings, the use of access control List (ACL) to prevent illegal data acquisition, and the use of advanced Encryption Standard (AES128) symmetric password to flexibly determine its security attributes. The first level is essentially no security mode, which devices can choose to transfer data in if security is not important or if the upper layer has provided sufficient security protection for certain applications. For the second level of security, devices can use access control lists (ACLs) to prevent unauthorized devices from obtaining data, and encryption is not implemented at this level. The third level of security uses symmetric passwords under the Advanced Encryption Standard (AES) for data transfer. AES can be used to protect data load and prevent attackers from impersonating legitimate devices. Each application can determine its security attributes flexibly.
(8) License-free frequency band: use direct sequence spread spectrum in industrial science medical 2.4GHz (global) band.