The third generation wireless communication standard
Today, we are entering the third-generation wireless communication stage. Or the "Internet contains everything" stage, this stage uses wireless sensors and control technology to connect the human world and the virtual electronic world.
Sensors and control networks do not enhance people's communication. Instead, they allow sensors and operators to interact to create a more dynamic world, thereby avoiding human errors and reducing labor costs.
Ultra-low power wireless sensor networks can bring benefits to many applications. This includes monitoring temperature, vibration, humidity, position, liquid level, etc. In the factory, they can be connected to control and actuators such as HAVC systems, storage systems, robot systems, or temperature control systems.
There are many examples like this. For agricultural applications, the information of temperature sensors and soil moisture sensors can be collected through wireless sensor networks to monitor farmland, vineyards, and greenhouses, and automatically adjust irrigation and fertilization.
For many real-world applications, low-power wireless sensor networks have many advantages, including no need for cables, increased flexibility in space-constrained or hazardous areas, easy installation, increased safety, and reduced maintenance costs. However, the development of wireless sensors depends entirely on the progress of the development of industry standards.
Industrial standards promote the development of wireless applications. Wireless communication has been greatly developed under the promotion of industrial standards. The standard provides flexibility for OEMs and integrators to choose, allowing devices from different vendors to be interoperable, which is the most important in all applications.
Compared with most wireless networks, the requirements of sensor networks are quite different, and the power consumption index is the most obvious difference. For wireless sensor network transceivers, the de facto standard is the IEEE 802.15.4 specification (ZigBee and other versions). Many vendors have begun to provide transceiver chips based on the 802.15.4 protocol. Some chips are a simplification of standard protocols, while others provide additional features for special applications. For example, GreenPeak's GP500 transceiver contains many low-power features that can be used for button battery-powered and self-collected energy-powered applications.
Some manufacturers also provide sensor network applications using Bluetooth and Wi-Fi technology. The comparison between IEEE 802.15.4 and Bluetooth technology is shown in Table 1. They all use a non-standard form, using IEEE 802.15.4 protocol to achieve in the country. The IEEE 802.15.4 protocol specification provides the most basic low-power wireless sensor network applications and is widely accepted.
Table 1 Comparison of main parameters of IEEE 802.15.4 and Bluetooth
Promotion of ZigBee Alliance
The ZigBee Alliance is an independent standardization organization composed of technology providers and OEM product companies. At the end of 2007, the alliance finalized the ZigBee and ZigBee PRO network protocol specifications.
From the perspective of use, the ZigBee network protocol stack is very suitable for home applications. The home network usually includes 10, or up to 100 devices. The ZigBee PRO network protocol stack is a superset of ZigBee, which increases network capacity and the ability to handle conflicts with other wireless technologies. The characteristics of ZigBee PRO make it very suitable for large-scale applications, especially in commercial buildings.
Another feature of ZigBee PRO is that it requires more memory space, which makes it more expensive. In the consumer electronics market, which is extremely cost-sensitive, every additional cost limits the possibility of adopting this technology. However, thanks to the decreasing cost of semiconductors, it can be predicted that in the short term, the cost difference between ZigBee and ZigBee PRO will be negligible, and more applications will adopt ZigBee PRO.
ISA-100 and wireless HART standards
ISA-100 and wireless HART are two industrial automation wireless standards. ISA-100 was initiated by the Instrument, Systems and Automation Association (ISA), a non-profit technical association for industrial automation. Wireless HART is not a complete industrial sensor protocol, it is a complement to the old but popular HART industrial wired bus standard for industrial automation. Since ISA-100 and wireless HART basically solve the same problem, it is currently being tested whether the two standards can be combined. The comparison of the above several low-power wireless protocols is shown in Table 2.
Table 2 Comparison of low-power wireless protocols
In addition to the IEEE 802.15.4 standard, private wireless communication technology also has many technologies that can be used to implement private transceivers. Its main purpose is to reduce complexity and reduce potential costs.
Private technology can be developed faster than standard technology because there is no need to agree between different companies. It should also be seen that if the private solution will achieve sufficient output, it will also reduce costs. Reducing complexity can sometimes sacrifice performance and limit its scope of application.
Even if the recent progress is within the scope of the standard, technology providers can have more room for innovation. For example, GreenPeak's Emerald GP500C transceiver and network protocol stack are compatible with the IEEE 802.15.4 standard, but add features for ultra-low power applications.
Another development is the low-power routing (LPR) technology that will soon appear in the standard. In LPR networks, battery-powered devices can receive messages from neighboring devices and forward the information to further communication links. The purpose of other standards to provide this function is simply to continuously power the device so that it is always in the listening state. LPR adds a time synchronization mechanism to the network, allowing devices to wake up at the same time to initiate communication and avoid continuous operation of the device.
IEEE Std 802.15.4-2003.pdf standard
The industry has begun to look for wireless network standards that do not require batteries. There are many ZigBee protocols for special functions-a subset of the ZigBee protocol. These are smaller, more task-oriented, and lower power consumption protocol stacks. Special ZigBee protocols for Smart Energy and Home AutomaTIon have been developed and released. The new batteryless power supply agreement is still under development and is expected to be completed in the first quarter.
Jinan Huajiang environmental protection and energy saving Technology Co., Ltd , https://www.hjnewenergy.com