IEEE802.15.4 protocol framework and communication characteristics

It's time for another week's "What to Watch This Week". I don't know if you guys think about Xiao Yi? In response to the needs of fans and friends, this week Xiaoyi will share with you some related content of industrial IoT terminals the IEEE802.15.4 protocol. Data transmission model, PHY layer physical characteristics and frame structure, remember to keep paying attention!

01 What is the purpose of the IEEE802.15.4 protocol?

The IEEE802.15.4 standard aims to provide a wireless personal area network (WPANs) for data transmission over relatively short distances. Unlike wireless local area networks (WLANs), connections via WPANs involve little or no infrastructure , so it has the characteristics of small size, energy saving, and low cost, and is suitable for various equipment solutions.

02 What are the characteristics of the IEEE802.15.4 protocol?

The rate of wireless data transmission includes 250kb/s, 100kb/s, 40kb/s, 20kb/s

Support both star and Wireless serial lora module point-to-point network topologies

There are two address formats, 16-bit and 64-bit, of which the 64-bit address is the only extended address in the world

Optional Guaranteed Time Slots ((GTSs)

Carrier sense multiple access with collision avoidance (CSMA-CA)

Support acknowledgment (ACK) mechanism to ensure transmission reliability

low power consumption

With channel energy detection (ED)

With Link Quality Indicator (LQI)

Working on 16 channels of 2.4G ISM frequency band, 30 channels of 915 frequency band, 3 channels of 868 frequency band

In the IEEE802.15.4 network, according to the communication capability of the device, it can be divided into Full Function Device (Full Function Device, FFD) and Reduced Function Device (Reduced Function Device, RFD).

FFD operates in the network in three roles: coordinator, (PAN) coordinator, and device. FFD devices can communicate with each other and between FFD devices and RFD devices. RFD devices cannot communicate directly with each other, but can only communicate with FFD devices, or forward data through an FFD device.

RFDs are suitable for very simple applications such as optical switches or passive infrared sensors that do not need to send large amounts of data and may only be associated with one FFD at a time, so the RFD can be implemented using minimal resources and memory capacity.