1. Version 1.1:
The transmission rate is about 748 ~ 810kb / s. due to the early design, it is vulnerable to the interference of similar communication products between the same frequency and affect the communication quality. This initial version supports the transmission requirements of stereo sound effects, but it can only work in (simplex) mode. In addition, indicators such as bandwidth frequency response are not ideal, so it is not the best stereo transmission tool.
2. Version 1.2:
Similarly, the transmission rate is only 748 ~ 810kb / s, but the anti-interference frequency hopping function of software is added. (too deep technical theory will not be detailed!). It supports the transmission requirements of stereo sound effect, but it can only work in (simplex) mode. In addition, the bandwidth frequency response is still not ideal, and it can not be used as a stereo transmission tool.
3. Version 2.0:
2.0 is an improved version of 1.2. The transmission rate is about 1.8m/s ~ 2.1m/s, and there can be (duplex) working mode. That is, while making voice communication, it can also transmit files / high-quality pictures. Of course, version 2.0 also supports stereo operation.
Subsequently, the stereo decoding chip is added to the chip of Bluetooth version 2.0, so even A2DP (advanced audio distribution profile) can not be needed.
4. Version 2.1:
In order to improve the problems of Bluetooth technology, the Bluetooth SIG Organization (special interest group) launched.
Bluetooth 2.1 + EDR version of Bluetooth technology. Improve the device pairing process: in the past, in the connection process, it was necessary to use the personal identification code to ensure the security of the connection, while the improved connection method will automatically use the digital password for pairing and connection. For example, as long as the connection specific device is selected in the mobile phone option, after confirmation, the mobile phone will automatically list the devices available in the current environment, And automatic connection; In terms of short-distance pairing: it also has NFC for pairing and communication transmission between two Bluetooth enabled mobile phones(near field communication) mechanism; Better power saving effect: sniff is added to Bluetooth version 2.1.
The function of subrating can save power by setting the transmission interval of mutual confirmation signals between the two devices. Bluetooth 2.1 extends the signal transmission interval of mutual confirmation between devices from 0.1 second in the old version to about 0.5 seconds, which can greatly reduce the workload of Bluetooth chip and give Bluetooth more time to sleep completely. According to the official report, after adopting this technology, the standby time of Bluetooth device after turning on Bluetooth online can be effectively extended by more than 5 times, and began to support full duplex communication mode.
5. Version 3.0 + HS:
On April 21, 2009, the Bluetooth Technology Alliance (bluetoothsig) officially issued a new generation of standard regulations"Bluetooth core specification version 3.0 high speed", the core of Bluetooth 3.0 is "generic alternate MAC / PHY" (AMP), which is a new alternating RF technology that allows the Bluetooth protocol stack to dynamically select the correct RF for any task. The technologies originally expected to be used in the new specification include 802.11 and UMB, but the application of UMB is cancelled in the new specification. The new version of the 802.0 wireless protocol will naturally have a higher transmission speed. By integrating "802.11pal" (protocol adaptation layer), the data transmission rate of Bluetooth 3.0 is increased to about 24mbps (802.11wi-fi can be called when necessary to realize high-speed data transmission)., It is eight times that of Bluetooth 2.0. It can be easily used for data transmission from video recorder to HD TV, PC to PMP, UMPC to printer. In terms of power consumption, transmitting a large amount of data at high speed through Bluetooth 3.0 will naturally consume more energy. However, due to the introduction of enhanced power control (EPC) mechanism and 802.11, the actual idle power consumption will be significantly reduced, and the standby power consumption of Bluetooth devices is expected to be preliminarily solved. In addition, the new specification also has two technologies: General test method (GTM) and one-way broadcast connectionless data (UCD), and includes a set of HCI instructions to obtain the key length. It is said that PCs equipped with Bluetooth 2.1 module can theoretically support Bluetooth 3.0 by upgrading firmware. Alliance members have begun to develop Bluetooth 3.0 solutions for device manufacturers.
6. Bluetooth 4.0
Bluetooth 4.0 is the upgrade standard of Bluetooth 3.0. The most important feature of Bluetooth 4.0 is power saving. The extremely low operation and standby power consumption can make a button battery work continuously for several years. In addition, many features such as low cost and cross vendor interoperability, 3-millisecond low delay and AES-128 encryption can be used in pedometer, heart rhythm monitor, intelligent instrument, sensor, Internet of things and many other fields, greatly expanding the application scope of Bluetooth technology.
6.2 main features:
Bluetooth 4.0 is a supplement to Bluetooth 3.0 + HS specification. It is specially for wireless solutions with high requirements for cost and power consumption. It can be widely used in many fields, such as health care, sports and fitness, home entertainment, security and so on.
It supports two deployment modes: dual mode and single mode. In dual mode, the low-power Bluetooth function is integrated into the existing classic Bluetooth controller, or the low-power stack is added on the existing classic Bluetooth Technology (2.1 + EDR / 3.0 + HS) chip. The overall architecture is basically unchanged, so the cost increase is limited.
Single mode can only be used with BT4 0 is mutually transmitted and cannot be downward compatible (cannot be connected with 3.0 / 2.1 / 2.0); Dualmode is downward compatible with BT4 0 transmission can also be transmitted with 3.0 / 2.1 / 2.0.
Single mode is for highly integrated and compact devices. It uses a lightweight link layer to provide ultra-low-power standby mode operation, simple device recovery and reliable point-to-multipoint data transmission. It also allows networked sensors to arrange the order of low-power Bluetooth traffic in Bluetooth transmission, as well as advanced energy-saving and secure encrypted connection.
Bluetooth 4.0 integrates three specifications, including traditional Bluetooth technology, high-speed technology and low-power technology. Compared with version 3.0, the biggest difference is low power consumption. "The power consumption of version 4.0 is 90% lower than that of the old version and is more power-saving." with the expansion of Bluetooth technology from traditional application fields such as mobile phones, games, headphones, portable computers and cars to new fields such as the Internet of things and medical treatment, the requirements for low power consumption will be higher and higher. Version 4.0 strengthens the low power performance of Bluetooth in data transmission. "
7. Bluetooth 4.1
If Bluetooth 4.0 focuses on power-saving features, the keyword of this upgrade of Bluetooth 4.1 should be IOT (full Networking), which means networking all devices. In order to achieve this, the improvement of communication function is one of the most important improvements of Bluetooth 4.1.
7.2 main features
1) Transmission speed of batch data
The first is the transmission speed of batch data. As we all know, the transmission rate of Bluetooth has always been very bad, which is incomparable with the Gigabit WiFi. Therefore, Bluetooth 4.1 has been upgraded on the basis of Bluetooth 4.0 Le, which has been widely used, so that batch data can be transmitted at a higher rate. Of course, this does not mean that streaming video can be transmitted at high speed with Bluetooth. This improvement is mainly aimed at the emerging wearable devices.
For example, the already common health bracelet does not send a large data stream. Through Bluetooth 4.1, the information collected during running, swimming and cycling can be transmitted to mobile phones and other devices more quickly, and users can better monitor the condition of sports in real time, which is very useful.
In the era of Bluetooth 4.0, all devices using Bluetooth 4.0 le are labeled with "Bluetooth smart" and logo of "Bluetooth smartready". Bluetooth smart ready device refers to PC tablet, mobile phone and other connection center devices, while Bluetooth smart device refers to Bluetooth headset, keyboard and mouse and other expansion devices. The roles between these devices have been arranged long ago. There is no role exchange, and only 1-to-1 connection can be made. In Bluetooth 4.1 technology, the device is allowed to act as the functions of "Bluetooth smart" and "Bluetooth smart ready" at the same time, which means that multiple devices can be connected to one Bluetooth device. For example, a smart watch can not only be used as a central hub to receive the movement information collected from the health bracelet, but also as a display device to display the messages from the smart phone E-mail, SMS. With the help of Bluetooth 4.1 technology, smart watches, smart glasses and other devices can become a real central hub.
2) Connect to the network via IPv6
In addition, the problem that it is not easy for wearable devices to surf the Internet can also be solved through Bluetooth 4.1. The new standard adds a dedicated channel to allow devices to be used online through IPv6. For example, if a Bluetooth device cannot access the Internet, after connecting to a device that can access the Internet through Bluetooth 4.1, the device can directly connect to the network through IPv6 to realize the same functions as WiFi. Although limited by the transmission rate, the Internet application of the device is limited, but operations such as synchronizing data and sending and receiving e-mail can be realized. The advantage of this improvement is that sensors and embedded devices can connect to mobile phones and the Internet only by Bluetooth. Relatively speaking, WiFi is mostly used to connect to the Internet. The effect of connecting devices is general, and the function of Bluetooth cannot be achieved. In the future, as the Internet of things gradually enters our life, the status of wireless transmission in daily life will be higher and higher. As the most popular transmission mode, Bluetooth will play an important role in the "Internet of things". However, it will take longer for Bluetooth to fully adapt to IPv6, so it depends on how chip manufacturers help Bluetooth devices increase IPv6 compatibility.
3) Simplify device connectivity
Driven by major mobile phone manufacturers and PC manufacturers, almost all mobile devices and laptops are equipped with Bluetooth modules, and users use Bluetooth more. However, a large number of users still feel that Bluetooth is very troublesome to use. In the final analysis, it is caused by the complex pairing and connection of Bluetooth devices. Imagine if a smart watch connected to a mobile phone has to be manually selected once in the setting interface every time it is disconnected, which is very troublesome. The previous solution to this problem is that manufacturers add NFC chips to both Bluetooth devices to simplify the steps of re pairing through NFC near-field communication, which is a good idea. Only the number of products equipped with NFC chips is small, and the price is high, which is very small.
Bluetooth 4.1 has made improvements to this point. It has greatly modified the connection and reconnection between devices, which can provide manufacturers with more design permissions during design, including setting frequency band, creating or maintaining Bluetooth connection. This change has significantly improved the flexibility of Bluetooth device connection. The two devices with Bluetooth 4.1 have been paired successfully before. When reconnecting, you can reconnect as long as the two devices are close to each other without any manual operation. For example, when using Bluetooth 4.1 headphones in the future, just turn on the power switch. There is no need to operate on the mobile phone. It is very simple.
4) Peaceful coexistence with 4G
In the field of mobile communication, the hottest topic in the near future is 4G, which has become an irreversible development trend of global wireless communication networks. Bluetooth 4.1 is also optimized specifically for 4G to ensure peaceful coexistence with 4G signals. This improvement is called "coexistence" by the Bluetooth technology alliance. You may wonder whether mobile network signal and Bluetooth have coexisted for a long time. Why should Bluetooth 4.1 be specially improved for this? This is because in practical applications, if the two transmit data at the same time, Bluetooth communication may be disturbed by mobile network signals, resulting in the decline of transmission rate. Therefore, in the new Bluetooth 4.1 standard, once Bluetooth 4.1 and 4G networks are transmitting data at the same time, Bluetooth 4.1 will automatically coordinate their transmission information, so as to reduce the interference of other signals to Bluetooth 4.1, and users don't have to worry about the decline of transmission rate.
5) The enhancements provided by Bluetooth 4.1 include:
AES encryption technology provides a more secure connection. This function makes the wireless headset more suitable for security oriented applications such as government, medical treatment and banking.
You can control headphones, speakers and strip speakers through the exclusive Bluetooth smart remote control, and support synchronous playback of audio streams from another completely different device.
Bluetooth 4.2 standard
On December 4, 2014, the Bluetooth 4.2 standard was issued, which improved the data transmission speed and privacy protection, and can directly access the Internet through IPv6 and 6LoWPAN. Under the new standard, if Bluetooth signal wants to connect or track user equipment, it must be approved by the user, otherwise Bluetooth signal will not be able to connect and track user equipment.
The speed has become faster. The data transmission speed between the two Bluetooth devices has increased by 2.5 times, because the capacity of Bluetooth smart data packet has increased, and the amount of data it can hold is about 10 times that before.
8.Bluetooth 5.0 protocol officially released in London on June 16, 2016 us time, it is the most advanced Bluetooth protocol standard at this stage.
1. Faster transmission speed
According to the developers of Bluetooth 5.0, the transmission speed of the new version of Bluetooth is limited to 2Mbps, twice that of the previous version of 4.2le. Of course, you are unlikely to reach this limit speed in real life, but you can still experience a significant speed increase.
2. Longer effective distance
Another important improvement of Bluetooth 5.0 is that its effective distance is four times that of the previous version. Therefore, in theory, when you stand 300 meters away from the Bluetooth speaker with your mobile phone, it will continue to play your favorite songs. In other words, in theory, the effective working distance between Bluetooth transmitting and receiving devices can reach 300 meters. Of course, the actual effective distance also depends on the electronic device you use.
3. Navigation function
In addition, Bluetooth 5.0 will add more navigation functions, so this technology can be used as indoor navigation beacons or similar positioning devices. Combined with WiFi, indoor positioning with an accuracy of less than 1 meter can be realized. For example, if you are a road addict, you can still use Bluetooth technology to find a way in the business center of Nuo University.
4. Internet of things function
The Internet of things has been optimized continuously for the lower performance of Bluetooth 5.0.
5. Upgrade hardware
Some previous Bluetooth version updates only require software upgrades, but Bluetooth 5.0 is likely to require upgrades to new chips. However, the old hardware can still be compatible with Bluetooth 5.0, so you can't enjoy its new performance. The flagship mobile phone equipped with Bluetooth 5.0 chip will come out in 2017. It is believed that medium and low-end mobile phones will also continue to have Bluetooth 5 chip built in. Apple will be one of the first manufacturers to use the technology.
6. More transmission functions
9.The new Bluetooth 5.0 can add more data transmission functions. Hardware manufacturers can create more complex connection systems through Bluetooth 5.0, such as beacon or location services. Therefore, the advertisement data sent through the Bluetooth device can send a small amount of information to the target device, even without pairing.
7. Lower power consumption
As we all know, Bluetooth is a necessary function of smart phones. As more and more smart devices and mobile payments need to turn on Bluetooth in order to enjoy convenient functions, it is gradually integrated into people's life. The power consumption of Bluetooth has become a major killer of the standby time of smart phones. Therefore, Bluetooth 5.0 will greatly reduce the power consumption of Bluetooth, so that people no longer have to worry about the short standby time in the process of using Bluetooth.
8. Truly support lossless transmission
It supports 24bit / 192Khz lossless sound source transmission, which poses an effective threat to the existing WiFi high fidelity lossless audio transmission.