[ZigBee] 1, ZigBee introduction

Objective

At present, China vigorously promote the internet of Things is the main battlefield of ZigBee applications, the Internet of things through intelligent sensing, recognition technology and pervasive computing (I also specifically applied for a domain name PSJS.VIP), ubiquitous network fusion application, known as the second computer, the world's information industry after the development of the third wave. If you want to make a difference on the internet of Things, now open the door to ZigBee learning!

1, the background of ZigBee production

In some areas, data throughput requirements are low and power consumption is lower than the power consumption provided by existing standards. Therefore, a communication link and a low complexity wireless transceiver are designed to maintain the minimum flow rate, and the core problem to be considered is low power consumption and low price design. This requires that the standard should provide low bandwidth, low data transfer rate applications.

2, the relationship between ZigBee and IEEE 802.15.4

Advantages of the IEEE 802.15.4 standard
A: Low power consumption
B: Low Price
C: Low data transfer rate
Tasks of the IEEE 802.15.4 standard development team
A: Physical Layer (DSSS): Modulation of data transmission and reception demodulation, media selection, channel selection.
B:mac Layer (CSMA/CA): Generates Web beacons, supports device security, and so on.

ZigBee is built on the IEEE802.15.4 standard, because the IEEE 802.15.4 standard defines only the physical layer protocol and the MAC layer protocol, so the ZigBee Alliance is established, the ZigBee Alliance standardizes its network layer protocol and API, and also develops the security layer. After the improvement of the ZigBee Alliance to the IEEE 802.15.4, this really formed the ZigBee protocol stack (Zstack).

3, the characteristics of ZigBee

Low data transfer Rate: 10kb/sec ~250kb/sec, focusing on low-transmission applications
Low power consumption: Two normal 5th-cell batteries can be used for 6-24 months in low power standby mode

IEEE 802.15.4 (ZigBee) operates in the ISM band, defining two bands, 2.4GHz bands, and 896/915mhz bands. In IEEE 802.15.4, 27 channels are specified:

?? In the 2.4GHz band, a total of 16 channels, channel communication rate of 250kbps;
?? In the 915MHz band, a total of 10 channels, channel communication rate of 40kbps;
?? In the 896MHz band, there are 1 channels with a channel communication rate of 20kbps.

4. ZigBee Network topology Model

ZigBee network topology mainly includes star network and network type. Different network topology corresponds to different application areas, in ZigBee wireless network, different network topology configuration of network nodes are different, network node type: Coordinator, router and terminal node, the specific configuration according to need to decide, the specific content will be explained in later chapters, here, Readers only need to have a conceptual understanding of the topology of the network.

Mesh Mesh network Topology network has a powerful function, the network can be a multi-hop way to communicate, the topology can be composed of extremely complex network, the network also has self-organization, self-healing function.

5. ZigBee Application Range

ZigBee has been widely used in the industry chain of the IoT industry, such as smart grid, intelligent transportation, smart home, finance, Mobile POS terminal, supply chain automation, industrial automation, intelligent building, fire protection, public safety, environmental protection, meteorology, digital medical, remote sensing, agriculture, forestry, water, coal, Petrochemical and other fields.

6. A typical system framework for ZigBee applications

Link

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[ZigBee] 1, ZigBee introduction