What is the difference between Wifi, Bluetooth and ZigBee?

    In the era of the Internet of Everything, wireless communication technology is becoming more and more important. However, there are so many wireless communication technologies on the market, it is unavoidable to make people dazzled. However, if you want to count the three giants of wireless communication today, you should push Wi-Fi , Bluetooth ( Bluetooth ) and ZigBee . What is the difference between these three wireless technologies that are currently becoming a tripartite trend?       


Respective strengths and applicable fields

In terms of development order, Wi-Fi was the first, followed by Bluetooth, and then ZigBee . This order also caused differences in the scale and resources of their alliance organizations, which affected their respective development situations.


Wi-Fi is undoubtedly the one among the three major wireless technology standards, the most rigorous and detailed alliance specification, the most invested manufacturers, the broadest application base in the market, the most ambitious in terms of integration and update, and it covers the widest range of development, from Low-frequency 2.4GHz to high-frequency 5GHz , even ultra-high frequency 60GHz , in addition, long transmission distance, high transmission rate is its specialty, but high power consumption has always been its fatal flaw. However, in recent years, Wi-Fi has also begun to develop low-power technologies, such as the Wi-Fi Aware technology launched last year that can explore and connect nearby devices in an environment without a wireless network.


For Bluetooth, which developed slightly later than Wi-Fi , because it can carry up to 1MB per second of transmission capacity, and at the same time has high security, encryption protection can be set, and the frequency can be changed 1,600 times per minute, but the effective transmission distance Shorter, the traditional version is about 10 meters, so it is more invested in the data transmission application of personalized sensory experience, so the supporting development in the field of sound applications is the most mature. Compared with Wi-Fi , Bluetooth's low power consumption, low cost and high security are its advantages, and the Bluetooth SIG also obviously focuses on this. It is currently developed to version 4.2 . In addition to improving the transmission distance and transmission rate, It further reduces its power consumption, and adds privacy functions to strengthen security.


As for ZigBee , because it was first developed for the purpose of automatic control, it is the most suitable wireless communication technology for intelligent control applications such as smart factories, smart homes, and smart buildings. In the field of control applications, ZigBee has a rich variety of devices, and the supporting protocol language has been relatively completely defined. In addition, in the design of the basic communication protocol, ZigBee has considered more than one-to-thousand communication from the beginning, and adopts jump points along multiple paths. Communication ( multi-hop ), so it is more mature than Wi-Fi and Bluetooth in the application of equipment automation. Because ZigBee communication only focuses on sensing and control, the amount of information it transmits is very small, and because the device does not need to be turned on all the time, it is the most suitable for Wi-Fi and Bluetooth in this application. It is a wireless communication technology that saves power. In addition, the hardware device of ZigBee is also the cheapest among the three, so the cost is also the lowest. As for the security part, since it supports the advanced encryption standard AES (Advanced Encryption Standard) , it is also possible as long as it is properly set. Extremely high security. It can be said that low transmission rate, low cost, power saving, security, and dedicated communication between devices ( Machine to Machine , M2M ) are the basic characteristics of ZigBee .


However, the problem with ZigBee is that its applications other than equipment automation are very weak, and it can only stick to the field of automatic control. At present, it emphasizes the trend of smart networking combined with mobile devices such as mobile phones, because the wireless technologies used by mobile devices are only Wi-Fi and Bluetooth. Therefore, it is necessary to rely on the Gateway ( gateway device ) that can convert various communication protocols to play a key intermediary role. This is why many manufacturers of smart home solutions are actively working on Gateway .


verification standard

So there are so many products on the market that claim to have Wi-Fi , Bluetooth, and ZigBee technologies. Is there any certification standard as a basis?


All wireless communication technologies are generally subject to two certification standards, and therefore must be verified before the relevant products are launched. The two certification specifications, one is the control of wireless communication by laws and regulations of various countries, and the other is the certification of technology by various technical alliances. Since the two certification specifications are concerned about different points, the direction of testing is also different. Therefore, there is no way to cover each other in terms of verification. The verification of national regulations is mandatory, and the alliance certification depends on the specifications of each alliance. The main focus of national regulations is on the control and management of wireless spectrum. When the power is higher and the closer to the forbidden frequency band, the control is stricter; alliance certification is a qualification certificate that the technology meets the performance, which is intended to protect the intellectual property rights of the alliance technology, and Maintain technical quality.


Alliance Certification

As for the part of the alliance certification, Wi-Fi , Bluetooth, and ZigBee are different in terms of the binding force of the certification and the verification items.


Among the three wireless technologies, only Bluetooth technology has clear intellectual property rights constraints, and the other two are voluntary and not mandatory in alliance certification. That is to say, if you use Bluetooth-related technologies without certification, you will suffer infringement However, products that meet Wi-Fi and ZigBee technology qualifications do not necessarily need to apply for alliance certification. Therefore, related equipment that has not been certified by Wi-Fi and ZigBee technology alliances may not be compatible with Wi-Fi and ZigBee devices.


In the part of the verification project, the Wi-Fi Alliance does not care about the wireless radio frequency power of the product. What it requires is to verify whether the security mechanism of the Wi-Fi product is normal in the application environment and whether it can achieve the desired transmission. Speed, whether it can perform mutual synchronization with other Wi-Fi devices, file transfer and sharing, remote printing, projection projection and other functions.


The ZigBee Alliance mainly focuses on application testing to verify whether the tested product responds correctly or sends commands as required, and whether the commands are executed correctly, so as to ensure that each new radio receiver and microcontroller can work normally in the ZigBee network. Operation to ensure the interoperability with other ZigBee products of different brands on the network.


The Bluetooth SIG not only requires to test the processing capabilities of the protocol layer of the product in different applications, that is, whether it can communicate well with other Bluetooth products, and whether it will get a correct response when issuing commands, it also requires testing the electrical properties, power, and power of the transmitter. Whether the modulation is normal, whether the phase conversion is correct, whether the sensitivity of the receiver and the anti-interference ability meet the specifications.


These verifications must be carried out in the certification laboratories authorized and designated by each alliance, with various testing equipment designated or licensed by each alliance. Among them, the accreditation evaluation of the Wi-Fi Alliance is the most stringent. Not every certification laboratory can be accredited, which also shows the rigor of the Wi-Fi Alliance.


Future prospects

For the prospects of Wi-Fi , Bluetooth, and ZigBee , in the short term, wireless communication will still maintain Wi-Fi as the basis of general wireless networks, ZigBee will serve as a means of M2M , and Bluetooth will serve the fields of personal wearables, audio-visual, etc. The three-point world pattern. After all, at this stage, the accumulated foundations of Bluetooth and ZigBee in their respective fields for many years of deep cultivation and management should not be underestimated, not to mention that each is constantly improving its own system. Although it will be a very long time for the standard to dominate one family, in the future we may witness more compatibility between various technologies and more frequent alliances among alliances in the increasingly fierce competition.