Comparative analysis of five smart home wireless technologies: KNX RF, Zigbee, Z-Wave, WiFi, BLE-MESH

Smart home solutions need to comprehensively consider multiple factors such as technology, cost, construction convenience, and aesthetics. The traditional smart home network wiring method is a wired network, which is inconvenient to construct and affects the appearance. Manufacturers are promoting smart home solutions based on wireless technology. Wireless networks do not require wiring and will not affect the indoor appearance. They save manpower and material resources in terms of integrated wiring. They are also convenient and fast, making them very suitable for smart homes.

Overview

Smart home solutions need to comprehensively consider multiple factors such as technology, cost, construction convenience, and aesthetics. The traditional smart home network wiring method is a wired network, which is inconvenient to construct and affects the appearance. Manufacturers are promoting smart home solutions based on wireless technology. Wireless networks do not require wiring and will not affect the indoor appearance. They save manpower and material resources in terms of integrated wiring. They are also convenient and fast, making them very suitable for smart homes.

There are many wireless solutions for smart homes on the market, which can provide users with more choices, but also confuse users, who don't know which wireless technology to choose to build a smart home system. Although there are many wireless solutions for smart homes, the mainstream smart home wireless technologies can be summarized as: Zigbee, Z-Wave, KNX RF, WiFi, Bluetooth, etc.

How to choose a smart home wireless solution? A horizontal comparison of the five major mainstream technologies.

Comparison of several mainstream smart home wireless technologies

This paper compares the above-mentioned mainstream smart home wireless technologies from several aspects, including wireless transmission technology, power consumption, number of nodes, security, openness, standardization and interoperability, industry applicability, and available software and hardware resources.

1. Wireless transmission technology

Zigbee: Based on IEEE 802.15.4 standard

• Operating frequency: 868MHz, 915MHz or 2.4GHz
• in the country, 2.4GHz is mainly used, 250kbps (2.4GHz)
• Modulation mode: BPSK/OQPSK, supports star, tree and mesh network topologies, supports 16 communication channels (2.4GHz)

Z-Wave: No standard for wireless transmission technology

• The operating frequency is 908.42MHz (USA), 868.42MHz (Europe)
• Modulation mode: FSK (BFSK/GFSK), data transmission rate is 40kbps, supports mesh network topology, supports single channel.

KNX RF: Based on EN 50090-5-3

• Operating frequency is 868MHz
• Modulation mode: 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 standards

• Operating frequency is 2.4GHz
• Modulation mode: MIMO-OFDM/DSSS/CCK, data transmission rate is above 11Mbps, supports ad hoc and infrastructure topologies, and supports 14 communication channels.

Bluetooth: Based on IEEE 802.15 standard

• The main operating frequency is 2.4GHz
• The modulation mode is GFSK, the data transmission rate is above 1Mbps, it supports point-to-point and peer-to-peer (Ad hoc) topologies, and supports 79 channels.

2. Power consumption

• Zigbee/Z-Wave/KNXRF are all designed for low power consumption, typically 1mW (0dBm)
• KNX RF even supports electromechanical energy harvesting (similar to EnOcean)
• WiFi consumes a lot of power and requires an external power supply, typically 36mW (16dBm)
• Bluetooth power consumption is between low power consumption and WiFi power consumption, typically 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 approximately 4000 nodes.
• WiFi: Theoretically 254 nodes, but the actual support is far lower than the theoretical value, generally not more than 20.
• Bluetooth: generally 8 nodes.

4. Security

• Zigbee: AES–128 and other security mechanisms.
• Z-Wave: It has a security layer and provides a key mechanism.
• KNX RF: Provides security mechanisms such as authentication and encryption above the application layer.
• WiFi: WPA/WPA2 security mechanism.
• Bluetooth: can provide security mechanisms such as authentication, encryption and key management.

5. Openness

• Zigbee: Zigbee Alliance, membership open.
• Z-Wave: Zensys leads the Z-Wave Alliance, which has open membership.
• KNX RF: KNX Association, fully open membership.
• WiFi: Fully open.
• Bluetooth: Bluetooth Technology Alliance, completely open.

6. Standardization and interoperability

• Zigbee: No international standards have been established, but internal protocol specifications and regulations for different fields have been established within the association. Currently, there are interoperability issues among products from different manufacturers.
• Z-Wave: No international standard has been established, but internal protocol specifications have been established within the association.
• KNX RF: has become an ISO/IEC standard, EN standard, and GB/T standard. Products from different manufacturers can interoperate and use unified software for configuration.
• WiFi: There are international standards, but no protocols have been established for the smart home field, and products from different manufacturers cannot interoperate.
• Bluetooth: There are international standards, but no protocols have been established for the smart home field, and products from different manufacturers cannot interoperate.

7. Industry Applicability

• Zigbee: It can be used in multiple application areas and is suitable for smart home applications, but is mainly used for functions such as sensing and control.
• Z-Wave: Specifically targeted at smart home applications, but mainly used for functions such as sensing and control.
• KNX RF: Specifically for smart home applications, it can be used with KNX TP (twisted pair), but is mainly used for functions such as sensing and control.
• WiFi: Aiming at multiple application areas, smart home applications can be used not only for sensing and control, but also for audio and video functions.
• Bluetooth: Aiming at multiple application fields, smart home applications can be used not only for sensing and control, but also for voice and other functions.

8. Available software and hardware resources

• Zigbee: Multiple chip manufacturers have provided solutions, such as TI, FREESCALE, ATMEL, Nordic, etc., as well as communication protocol stacks based on different hardware platforms.
• Z-Wave: Zensys provides dedicated chips.
• KNX RF: There are currently 2 hardware manufacturers and 2 software companies providing chip and protocol solutions.
• WiFi: Many manufacturers provide chip and protocol solutions, and protocols other than the application layer are open protocols.
• Bluetooth: Many manufacturers provide chip and protocol solutions.

Features Analysis

1. Zigbee

The wireless communication technology is advanced, with average anti-interference and penetration (mainly working at 2.4GHz), rich software and hardware development resources, and standardization and interoperability need to be improved. It is more suitable for applications in the smart home industry.

2. Z-Wave

The wireless communication technology is relatively advanced, with good anti-interference and penetration, single software and hardware development resources, few third-party solutions, and standardization needs to be improved, but good interoperability. It is suitable for smart home industry applications.

3. KNX RF

Wireless communication technology is simple but practical, with less software and hardware development resources, good anti-interference and penetration, and excellent standardization and interoperability. Wireless and wired can form a complete solution, suitable for smart home industry applications.

4. WiFi

Wireless communication technology is advanced, and software and hardware development resources are abundant. Anti-interference and penetration are average (mainly working at 2.4GHz). The standardization and interoperability of the smart home industry are poor. Due to high power consumption and node number restrictions, its application in the smart home industry is limited, but it has the strongest ability to integrate smart home applications into IT networks.

5. Bluetooth

Wireless communication technology is advanced, software and hardware development resources are abundant, and anti-interference and penetration are average (mainly working at 2.4GHz). The standardization and interoperability of the smart home industry are poor. Due to the number of nodes and topology, its application in the smart home industry is limited, but it is easy to integrate into smart terminals such as mobile phones and Pads.

Viewpoint

The above objective comparison of several mainstream wireless technologies used in smart homes is presented above. However, when it comes to which technology a company chooses and which product a customer chooses, in addition to the comparison of technological advancement, multiple factors such as technological maturity, reliability, and engineering implementation must also be considered.

Two more questions:

(1) Is it necessary to support wireless technology for Mesh networks?

Wireless technology that supports Mesh topology means that the wireless technology is more complex and can support more nodes and cover a wider area. However, given the complexity of Mesh topology, it will increase the difficulty of development and make network management more complex. In addition, more routes are not very meaningful in practical applications.

(2) Should a pure wireless solution be adopted at this stage?

Wireless technology has indeed brought a lot of convenience to smart homes, but it seems that relying solely on wireless technology cannot solve all application problems, and the reliability and stability of wireless technology still need to be improved, especially for public building applications. The wired + wireless solution is still the right choice at this stage.