The emergence of intelligent lighting is accompanied by the development of technologies such as Internet of Things, LED lighting, and wireless communication. Its typical feature is the individually controllable, convenient and flexible scene setting of lighting equipment, and can be seamlessly interfaced with other intelligent information systems (such as Intelligent sensor network, security monitoring network, intelligent energy network, etc., to meet different intelligent lighting needs with novel rendering mode. Therefore, intelligent lighting system needs to provide convenient and easy-to-operate system upgrade and transformation plan to adapt to the changing needs. Low-power wireless communication control systems are a key part of this.
As an important part of smart engineering, intelligent lighting is also a good application form in the Internet of Things system. The intelligent lighting solution based on low-power wireless transmission will be the future development trend. At present, the market environment is becoming more and more mature, and the establishment of relevant standards will be the boost to promote the development of the intelligent lighting market.
At present, there are many protocols used in the field of low-power wireless transmission, and a unified transmission specification has not yet been formed. The following is an example of the comparison of two current mainstream low-power wireless transmission protocols, Zigbee and Jennet-IP, to analyze the characteristics and development direction of low-power transmission protocols.
1, Zigbee agreement
The Zigbee protocol is characterized by small size, low cost, low power consumption and low transmission rate. It was jointly proposed by Motorola (USA), Mitsubishi (Japan), Philips (Netherlands), Invensys (UK) and other companies in 2002. Developed low-power wireless communication protocol.
The network layer and media access layer of the Zigbee protocol use the IEEE802.15.4 protocol as the protocol standard, and the IEEE 802.15.4 protocol is the IEEE 802 Wireless Personal Area Network (WPAN, Wireless Personal Area Network) group (established in December 2000) in 2003. Officially released in December, including the protocol standards adopted by its physical layer and MAC layer. The Zigbee Alliance released the Zigbee wireless communication protocol by defining the network layer and the application layer based on the physical layer (PHY) and the medium access layer (MAC) defined in IEEE802. 15.4 in December 2004.
(1) The main application features of the Zigbee wireless communication protocol are as follows:
1 low power consumption: Compared with other wireless network protocols, Zigbee protocol devices have very low power consumption, so the device life is extended a lot;
2 High reliability: The Zigbee protocol has a mechanism to avoid collisions. By adopting a dedicated time gap method, collisions in the process of transmitting data are avoided. In addition, an automatic routing mode is adopted in the transmission to improve transmission reliability.
3 low transmission rate: the Zigbee protocol supports a transmission rate ranging from 10 kb/s to 250 kb/s;
4 transmission delay is small: Zigbee protocol optimizes the application with high time delay requirement, which shortens the communication delay greatly. In addition, the time for Zigbee protocol device to activate from sleep state is also reduced a lot;
5 Supporting a large number of nodes: In theory, the Zigbee protocol network can support a maximum capacity of 65,000 nodes;
6 Security: The Zigbee protocol can provide corresponding security mechanisms for specific application needs. The AES.128 algorithm is used to protect data in CCM mode.
(2) The overall structure of the Zigbee protocol mainly includes the physical layer (PHY), the medium access layer (MAC), the network/security layer, and the application framework layer.
The 1 PHY layer is mainly responsible for controlling the opening and closing of the wireless transceiver, channel selection, energy detection, link quality, sending and receiving data packets through physical media, and the like;
The 2MAC layer is mainly responsible for channel access, transmission acknowledgement frame, time slot management, beacon management, transmission connection, and disconnection request. In addition, it provides support for appropriate security mechanisms, such as collision avoidance carrier sense multiple access. (CSMA-CA), time synchronization beacon optional superframe structure;
3 security layer is mainly responsible for key management, access and other functions;
4 network layer is mainly negative LR-WPAN network networking, data, etc.;
5 The application framework layer is mainly responsible for providing application software interfaces (APIs) to implement device management at the application layer. In addition, the application layer can also provide an application framework model for practical applications in order to develop applications.
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