ZigBee/WiFi/Bluetooth? Who is more suitable for smart home

1. ZigBee (Zifeng Protocol)

Introduction to ZigBee

Zigbee is the abbreviation of IEEE 802.15.4 protocol. It is a bee's splayed bee. The bee is the "dance" of flying and "zig" shaking wings to convey the position information of the pollen with the companion, and the ZigBee protocol. The method is similar to ZigBee. ZigBee is mainly suitable for automatic control and remote control. It can be embedded in various devices. It is characterized by near propagation distance, low power consumption, low cost, low data rate, and self-organizing network. The agreement is simple.

The main advantages of ZigBee are as follows:

Low power consumption

Compared to Bluetooth and WiFi, the same power (two AA batteries) can support the device for six months to two years, while Bluetooth can only work for a few weeks, WiFi can only work for a few hours.

2. Low cost

The ZigBee patent fee is waived, the transmission rate is small and the protocol is simple, which greatly reduces the cost of the ZigBee device.

3. Low drop rate

Due to ZigBee's collision avoidance mechanism, and at the same time, a dedicated time gap is reserved for the fixed bandwidth of the communication service, so that competition and conflict do not occur during data transmission; the function of the self-organizing network allows each node module to be between The contact can be established, and the received information can be transmitted through the line between each node module, so that the reliability of ZigBee transmission information is greatly improved, and it can be considered that it will not be dropped.

4. Strong networking ability

ZigBee's networking capabilities are superior, with 60,000 nodes each.

5. Security and confidentiality

ZigBee provides a set of security classes and software based on the 128-bit AES algorithm and integrates the security elements of IEEE 802.15.4.

6. Flexible working frequency band

The 2.4 GHz, 868 MHz and 915 MHz bands are all unlicensed.

The disadvantages of ZigBee are as follows:

Propagation distance

If the power amplifier is not applicable, the effective propagation distance of ZigBee is generally 10m--75m, which is mainly suitable for some small areas, such as home and office. However, if the node module is used as the receiving end and the transmitting end is sacrificed under the premise of sacrificing the advantage of its low drop rate, long-distance information transmission can be realized.

2. Low data transmission rate

In the 2.4 GHz band, ZigBee also has a propagation speed of only 250 Kb/s, and this is only the rate on the link and does not include frame header overhead, channel contention, acknowledgment and retransmission, and the actual applicable after removing these. The rate will be less than 100 Kb/s, and the rate will be shared by multiple nodes when running multiple applications.

3. There will be delay

ZigBee does not support time-division multiplexed channel access mode while randomly accessing the MAC layer. Therefore, when supporting some real-time applications, delays may occur due to sending multiple hops and collisions.

ZigBee specific application

The advent of ZigBee has been around for a long time, but due to the transmission rate and the current proportion of modules configured in electronic devices is almost zero, there are few famous applications before 2010. In the years when LEDs were hot, ZigBee was found to be suitable for lighting systems, such as smart home systems, which do not require a fast transfer rate. Recently, applications have also been implemented in wireless positioning systems and have been implemented on specific projects.

2. Bluetooth (Bluetooth Protocol)

Bluetooth introduction

The Bluetooth protocol was created by Ericsson and was developed with other industry-leading developers on May 20, 1999. The wireless technology was eventually named Bluetooth. Bluetooth technology is a wireless communication technology that enables electronic devices to establish network connections and transmit data or voice calls within a spatial range of 10 to 100 m.

Bluetooth development trend

The Bluetooth Special Interest Group (SIG) has announced the official release of the Bluetooth 4.0 version, and has developed technical standards and started the certification program. On the basis of maintaining the 3.0+HS high-speed transmission technology, Bluetooth 4.0 has joined the Wibree low-power transmission technology promoted by a certain developer.

Bluetooth 4.0 is a combination of IEEE 802.15.1 traditional Bluetooth, IEEE 802.11 physical layer and MAC layer and Wibree. It has a world of difference with Bluetooth, which is only applicable to WPAN in the past. Bluetooth will continue in the next few years. The development trend of several years has entered an application frenzy.

The biggest breakthrough and technical feature of Bluetooth 4.0 is the low-power transmission of Wibree. It uses simple GFSK modulation and thus has extremely low running and standby power consumption. Even a single button battery can support the device for more than a few years.

The network topology of Bluetooth 4.0 is simpler than that of ZigBee's star topology, and the transmission rate is several times higher than that of ZigBee. It has a large advantage over NFC in terms of transmission distance, and its wide application in the field of mobile phones and audio, as a The new technology that came out soon, its threat to ZigBee and NFC can not be ignored, and the future development is limitless.

The advantages of Bluetooth are as follows:

1. Low power consumption and fast transfer rate

The short data packet nature of Bluetooth is fundamental to its low-power technology, with transmission rates of up to 1 Mb/s, and all connections use advanced sniffing sub-rated function modes for ultra-low load cycling.

2. The connection time is short

It takes only a short 3ms for the Bluetooth application to open to establish a connection, and the approved data transfer can be completed at a few milliseconds of transfer speed and the connection is immediately closed.

3. Good stability

Bluetooth low energy technology uses a 24-bit cyclic repeat loop (CRC) to ensure maximum stability of all packets in the event of interference.

4. High security

CCM's AES-128 full encryption technology provides high encryption and authentication for data packets.

The disadvantages of Bluetooth are as follows:

1. The size of the data transmission is limited

High-speed frequency hopping makes Bluetooth transmit information with great security, but it also limits the data packets during Bluetooth transmission. Even in the so-called high-fidelity Bluetooth headset, the high and low frequency parts will be severely compressed.

2. The number of device connections is small

Compared with Wifi and ZigBee, the Bluetooth connection device capability is really poor. In theory, 8 devices can be connected. In fact, only 6-7 devices can be connected.

3. Single connectivity of Bluetooth devices

Suppose I connect a Bluetooth device with an A phone, then the B phone can't connect to it. I must disconnect the B phone from the Bluetooth device to connect to it.

Bluetooth application

The transmission of data from the original Bluetooth makes Bluetooth technology widely used on mobile phones, and then the popularity of Bluetooth headsets and Bluetooth wireless mice, and nowadays the most popular Bluetooth smart home system, the convenience of Bluetooth for people's lives is self-evident. With its high configuration ratio in electronic products, people's acceptance of new Bluetooth products will be higher than ZigBee, NFC and other products. Electronic curtains, vacuum cleaners, range hoods, smart wearables, and low-power Bluetooth 4.0 will have a larger application market.

3. WiFi (Wireless Fidelity Protocol)

Introduction to WiFi technology

WiFi (Wireless Fidelity) is short for IEEE 802.11. It is a short-range wireless transmission technology that supports data, image, voice and multimedia with an output rate of up to 54Mb/s. It can be used within a few hundred meters. The internet accessor receives the radio signal. The first version of WiFi was introduced in 1997, when the physical layer and the medium access control layer (MAC layer) were defined and the medium access layer (MAC) was standardized while specifying the basic transmission medium and network structure of the WLAN. Features and physical layer (PHY), where the physical layer uses FSSS (frequency modulation spread spectrum) technology, infrared technology and DSSS (direct sequence spread spectrum) technology. In 1999, the IEEE 802.11g and IEEE 802.11a standards were added to improve.

WiFi technology features

1. Wide transmission range

WiFi's radio wave coverage range is as high as 100 m, and even the entire building can be covered. Compared with the radius of only 15m Bluetooth, the advantage is quite obvious.

2. Fast transmission speed

The transmission rate of up to 54Mb/s enables WiFi users to receive the network anytime and anywhere, and can quickly enjoy a series of broadband information similar to online games, video on demand (VOD), distance education, online securities, telemedicine, video conferencing, etc. Value-added services. In this fast-developing information age, WiFi, which is still improving in speed, will be able to meet the needs of social and personal information development.

3. Health and safety

The WiFi device can't transmit more than 100 mW under the IEEE 802.11, and the actual transmit power may be 60~70 mW. Compared with similar communication devices, the mobile phone's transmit power is about 200 mW~1 W. The walkie-talkie is up to 5 W. The radiation of the WiFi products is smaller than the two.

4. High popularity

More and more electronic devices are equipped with WiFi, and mobile phones, laptops, tablets, and MP4s almost all include WiFi in their mainstream standard configuration.

WiFi development trend

Some time ago, WiFi Technology Alliance launched the WiFi Direct standard, which also indicates that the adoption rate of WiFi in netbooks, smart phones, TV sets, set-top boxes and other devices is rising, and it also begins to involve the Bluetooth traditional WPAN field. According to survey data from market research firm In-Stat, it is estimated that by 2013, 216 million electronic devices equipped with WiFi modules will be added worldwide.

The more popular Bluetooth and infrared in the traditional standard are currently only Bluetooth. The new configuration includes gravity sensing, GPS and WiFi, among which the WiFi configuration ratio is the highest. WiFi has become a standard in mobile phones and other similar electronic devices. Currently, almost all flat panels, notebook computers and smart phones on the market are equipped with WiFi modules.

Recently, David Murray, director of marketing for the GPS business group of Broadcom Wireless Connection Group, said that Broadcom's solution has more advantages than its competitors - in addition to using satellite signals, it also assists in positioning via WiFi and base stations. It is worth mentioning that the addition of WiFi enables accurate positioning of indoors that are difficult to receive satellite signals.

4. Bluetooth, WiFi, ZigBee feature comparison

5 Conclusion

At present, the electronic devices (mobile phones, tablets) with high penetration rate in the market are basically equipped with Bluetooth 4.0 modules and WiFi modules. In this respect, the degree of acceptance of the two on the client side is much greater than that of ZigBee. Years ago, Japan used to promote mobile phones with ZigBee modules. However, the cumbersome ZigBee protocol and the low transmission rate seem to be unable to catch up with the feeling of the times. Therefore, it has not been popularized, but its self-organizing network is characterized by two other types. The program can not be replaced. In the future smart home market, Bluetooth, due to its small size and low power consumption, may be developed in the direction of miniaturization, such as wearable electronic devices. With the characteristics of wireless networks almost everywhere, WiFi is sure to become the most accepted and widely used solution in the future. Now that ZigBee wants to break the deadlock and not be eliminated, it may really take a big transformation like Bluetooth 3.0 to enter Bluetooth 4.0.