Smart home has appeared as early as the nineties of the last century, but the expensive cost, complicated wiring and physical limitations have made the development of smart home almost stagnant, especially on the opposite side of the existing building, and the opportunity is impossible to transform. Fortunately, we have come to the era of the Internet of Things, an era that makes our lives simple, turning everything around us into a smartphone, a smart PC, and connecting them together through ready-made networks, so that we can easily operate them from anywhere on the planet. In this context, smart homes based on various wireless protocols have entered our lives with a momentum. Such a huge market and development prospects, will inevitably drive the development of technology, a variety of wireless networking modes have been improved, low power consumption, low-cost products more and more, so that we have more and more choices, there are mainly the following main networking modes:
Zigbee is based on IEEE80215.4 standard low-power personal area network protocols. The technology specified under this protocol is a short-range, low-power wireless communication technology. Zigbee has low power consumption, and two No. 5 batteries can last for 6 monthsLow-cost, Zigbee license-free royalty-free, $2 per chipShort delay, Zigbee's response speed is fast, generally only 15ms from sleep to working state, node connection into the network only 30ms, further saving power high capacity, Zigbee can use star, sheet and mesh network structure, by a master node to manage a number of sub-nodes, up to a master node can manage 254 sub-nodes, at the same time the master node can also be managed by the previous layer of network nodes, up to 65000 nodes of the network.
As an emerging short-range, low-rate wireless communication technology, Zigbee has received more and more attention and application. Especially in the field of smart home, most manufacturers have adopted Zigbee networking. But Zigbee also has shortcomings that cannot be ignored: First of all, the current domestic Zigbee technology mainly works in 24GHz-25GHzism microwave band, its diffraction ability is weak, the ability to penetrate the wall is weak, if the RF power amplifier is used, the right 2The amplification of 5G signals will increase power consumption and costSecondly, the main feature of Zigbee technology is that it supports ad hoc networks, but in the home environment, most of the home control devices are installed at fixed points, and the advantages of ad hoc networks no longer exist;Finally, relative to 65,000 nodes, we currently use up to 100 nodes in the home environment, which is not within our affordability, of course, with the reduction of the cost of Zigbee modules, there may be igbee modules installed on every item in the home in the future. At that time, it will be possible to make better use of its advantages.
Z-W**E is an emerging RF-based, low-cost, low-power, high-reliability, network-friendly short-range wireless communication technology. The operating frequency band is 90842MHz (USA) 86842MHz (Europe, the domestic use of the European frequency band, at present these two frequency bands are unlicensed frequency bands), FSK (BFSK GFSK) modulation mode, the data transmission rate is 96 kbps-40kbps, the effective coverage of the signal is 30m indoors and more than 100m outdoors, which is suitable for narrow bandwidth applications. With the increase of communication distance, the complexity of the device, power consumption and system cost are increasing, compared with the existing wireless communication technology, the design cost of Z-W**E is only about half of Zigbee, and the lightweight protocol and simple structure help to maintain lower power consumption than Zigbee, strongly promoting low-rate wireless personal area networks, at the same time, because its target is clearly positioned in the field of smart home, so the development of the field of smart home is faster than Zigbee. However, compared with Zigbee Frequency Hopping Spread Spectrum (FHSS) technology, the single-channel mode of Z-W**E has weak self-healing ability, is prone to interference, and has poor security, which are all problems that the Z-W**E Alliance needs to solve as soon as possible.
WiFi is currently the most widely used, the fastest transmission rate of wireless networking mode, is also the most well-known way, however, in the field of terminals, only occupy the PC and smart phones, and other passive intelligent terminal equipment is rarely used, the ultimate reason is because the power consumption is too large, compared with Zigbee, Bluetooth and other networking methods, WiFi power consumption is unacceptable, especially in the rapid development of the Internet of Things today, most of the networking devices are passive, so WiFi has not been optimistic about the development of the Internet of Things, although a large number of WiFi hotspots have been placed in China, and more will be installed in the future, but the application of other smart terminals has not been widely adopted. However, the current low-power wifi chip also has a lot of eye-catching research, especially the embedded real-time clock controller watchdog timer wifi chip, the chip's power management function will automatically control the power supply to maintain low-power standby mode when there is no device connection control, the power consumption is only a few W, it can make the dry battery use for more than a year, and the power consumption is almost the same as the power consumption of Zigbee, of course, in the future application, the cost reduction may occupy more markets.
Source: Wireless Connectivity Technology.
Original title: **Smart home wireless networking mode.
Author: Han Huan, Wang Huajun.