Dr. Linkun Wang

Deputy Director of Instrumentation Comprehensive Technology Research Institute of Machinery Industry

Leader of GB/T 20965 Standard Revision Working Group

"I. Overview

Smart home solutions need to take into account a number of factors such as technology, cost, ease of construction, aesthetics and so on. The traditional smart home network wiring is wired network, construction is not convenient, affecting aesthetics, the manufacturers are pushing the wireless technology-based smart home solutions. Wireless networks do not need wiring will not affect the interior aesthetics, saving the comprehensive wiring in this area of manpower and material resources, and has a convenient, fast and other characteristics, is very suitable for application in the smart home.

Currently on the market more wireless solutions for smart home, which on the one hand can provide users with more choices, but at the same time also brings confusion to the user, do not know which wireless technology to choose to build a smart home system. Although there are many smart home wireless solutions, the mainstream smart home wireless technology can be summarized as: Zigbee, Z-Wave, KNX RF, WiFi, Bluetooth, etc."

"II. several mainstream smart home wireless technology comparison

Now from the wireless transmission technology, power consumption, the number of nodes, security, openness, standardization and interoperability, industry applicability, available hardware and software resources and other aspects of the above several mainstream smart home wireless technology comparison.

1、Wireless transmission technology

Zigbee: based on IEEE 802.15.4 standard, working frequency of 868MHz, 915MHz or 2.4GHz, 2.4GHz is mainly used in China, 250kbps (2.4GHz), modulation: BPSK/OQPSK, support for star, tree, and mesh (mesh) network topology, support for 16 communication channels (2.4GHz). GHz).

Z-Wave: wireless transmission technology without standards, operating frequency 908.42MHz (USA), 868.42MHz (Europe), modulation: FSK (BFSK/GFSK), data transmission rate of 40kbps, support for mesh (mesh) network topology, support for single channel.

KNX RF: based on EN 50090-5-3, operating frequency is 868MHz, modulation: FSK, data transmission rate is 16kbps, supports peer-to-peer network topology, does not support mesh topology, supports 3 fast channels and 2 slow channels.

WiFi: based on IEEE 802.11 standard, main operating frequency is 2.4GHz, modulation mode: MIMO-OFDM/DSSS/CCK, data transmission rate is 11Mbps or more, supports self-organized network (Ad hoc) and infrastructure topology, supports 14 communication channels.

Bluetooth: based on IEEE 802.15 standard, the main operating frequency is 2.4GHz, modulation mode GFSK, data transmission rate of 1Mbps or more, support for peer-to-peer, and peer-to-peer network (Ad hoc) topology, support for 79 channels.

Power consumption

Zigbee/Z-Wave/KNXRF are designed for low power consumption, typical 1mW (0dBm), KNX RF even supports electromechanical energy acquisition (similar to the EnOcean method); WiFi power consumption is large, external power supply is required, typical 36mW (16dBm); Bluetooth power consumption between low power consumption and WiFi power consumption, typical 2.5 mW (4dBm). Typical 2.5 mW (4dBm).

3、Number of nodes

Zigbee: Theoretically, it can support more than 60,000 nodes.

Z-Wave: up to 232 nodes.

KNX RF: up to about 4000 nodes.

WiFi: theoretically 254 nodes, but the actual support is much lower than the theoretical value, generally no more than 20.

Bluetooth: typically 8 nodes.

4、Security

Zigbee: AES- 128 and other security mechanisms.

Z-Wave: has a security layer and provides key mechanisms.

KNX RF: provides security mechanisms such as authentication and encryption above the application layer.

WiFi: WPA/WPA2 security mechanism.

Bluetooth:

Security mechanisms such as authentication, encryption and key management can be provided.

5、Openness

Zigbee: Zigbee Alliance, open membership.

Z-Wave: Zensys leads the Z-Wave Alliance, open to members.

KNX RF: KNX Association, members are completely open.

WiFi: Fully open.

Bluetooth: Bluetooth Technology Alliance, fully open.

6、Standardization and Interoperability

Zigbee: no international standard has been established, the Association has established internal protocol specifications and regulations in different fields, and there are interoperability problems with different vendors' products at present.

Z-Wave: No international standard has been established, and internal protocol specification of the association has been established.

KNX RF: has become an ISO/IEC standard, EN standard, GB/T standard, products from different vendors can be interoperable and configured using unified software.

WiFi: there are international standards, but there is no statute established for the smart home field, and products from different vendors cannot realize interoperability.

Bluetooth: there are international standards, but there is no statute for smart home, and products from different vendors are not interoperable.

7、Industry applicability

Zigbee: It can be used for multiple applications and is suitable for smart home applications, but it is mainly used for sensing and control functions.

Z-Wave: specialized for smart home applications, but mainly used for sensing and control functions.

KNX RF: Specifically for smart home applications, can be used with KNX TP (twisted pair), but mainly used for functions such as sensing and control.

WiFi: Multi-application oriented, smart home applications can be used not only for sensing and control, but also for audio and video functions.

Bluetooth: For multi-application areas, smart home applications can be used not only for sensing and control, but also for voice and other functions.

8、Available hardware and software resources

Zigbee: There have been a number of chip manufacturers to provide solutions, such as TI, FREESCALE, ATMEL, Nordic, etc., as well as based on different hardware platforms of the communication stack.

Z-Wave: Zensys provides specialized chips.

KNX RF: Currently there are 2 hardware vendors and 2 software companies providing chips and protocol solutions.

WiFi: Numerous vendors provide chips and protocol solutions, and protocols beyond the application layer are open protocols.

Bluetooth: more vendors provide chip and protocol solutions."

"III. Characterization

1、Zigbee

Advanced wireless communication technology, general anti-jamming and penetration (mainly working in 2.4GHz), software and hardware development resources are richer, standardization and interoperability to be improved, more suitable for smart home industry applications.

2、Z-Wave

Wireless communication technology is more advanced, better immunity and penetration, single software and hardware development resources, fewer third-party solutions, standardization to be improved, better interoperability. Suitable for smart home industry applications.

3、KNX RF

Wireless communication technology is simple but practical, less hardware and software development resources, better immunity and penetration, standardization and interoperability are excellent. Wireless and wired can constitute a complete solution, suitable for smart home industry applications.

4、WiFi

Wireless communication technology is advanced, software and hardware development resources are abundant, and immunity and penetration are general (mainly working in 2.4GHz). The standardization and interoperability of the smart home industry is poor, due to high power consumption and the number of nodes limitations, the application in the smart home industry is limited, but its ability to integrate smart home applications into the IT network is the strongest.

5、Bluetooth

Advanced wireless communication technology, rich in software and hardware development resources, general immunity and penetration (mainly working at 2.4GHz). The standardization and interoperability of the smart home industry is poor, and its application in the smart home industry is limited due to the number of nodes and topology, but it is convenient to integrate into smart terminals, such as cell phones and pads."

"Fourth, the point of view

The above objective comparison of several mainstream used for smart home wireless technology, but for the company to choose which technology, as well as customers to choose which product, in addition to the comparison of technological sophistication, but also to consider the maturity of the technology, reliability, engineering implementation and many other factors.

Another two questions:

1) Is it necessary to support the wireless technology of Mesh network? Wireless technology supports Mesh topology indicates that its wireless technology is more complex, can support more nodes, covering a wider area. However, in view of the complexity of the Mesh topology, will increase the difficulty of development, and network management is complex, and more routes in the practical application of the significance is not great.

(2) Should we adopt a purely wireless solution at this stage? Wireless technology does bring a lot of convenience to the smart home, but at present see completely rely on wireless technology and can not solve all the application problems, and the reliability and stability of wireless technology still need to be improved, especially for public construction applications. The wired + wireless solution is still the right choice at this stage."