From the development history of Bluetooth, can you understand the past and present life of Bluetooth mesh? Think about three questions about the soul: where it comes from, where it goes, and what it wants to do. Prepare to learn Bluetooth mesh next.
Why is it named Bluetooth? This stems from a short story. In the tenth century Denmark there was a king named Harald Blatand, who was articulate and sociable. He united Norway, Sweden and Denmark. Because he likes to eat blueberries and his gums are often blue, he is known as the Bluetooth King. When determining the name, the designers felt that the name "Bluetooth" was very expressive, and that King Blatand's personality fit well with the characteristics of this technology, so the name "Bluetooth" was used. The Bluetooth logo design is taken from the letters "H" and "B" in the name Harald Bluetooth.
Barbaric Growth Stage
The core of Bluetooth is short-range radio communication. Its basis comes from Frequency Hopping Spread Spectrum (FHSS) technology, developed by Hollywood actress Hedy Lamarr and pianist George Antheil proposed in a patent filed in August 1942. They were inspired by the number of keys on a piano and controlled the torpedo by using radios with 88 different carrier frequencies. Since the transmission frequency is constantly jumping, it has certain confidentiality capabilities and anti-interference capabilities.
At first, this technology did not attract the attention of the U.S. military. It was not used by the military in wireless communication systems on the battlefield until the 1980s. Frequency hopping spread spectrum (FHSS) technology was later used to solve problems including Bluetooth, WiFi, and 3G mobile communication systems play a key role in wireless data transmission and reception issues.
The 1980s and 1990s were an era of explosive communication technology. At that time, many technology giants were studying a short-range wireless communication technology that could wirelessly connect different devices together.
In 1994, JaapHaartsen completed the core baseband part of this technology, and Sven Mattissson completed the radio frequency part, plus link management (LMP). These three parts constitute the core protocol of this technology. layer. This is the earliest Bluetooth technology, but it was not called Bluetooth at this time.
After a long period of barbaric growth, various standards have emerged one after another.
For the sake of convenience, it is impossible for every company to use its own standards, just like charging data cables. There are two charging data cables on the market, Apple and Android. Even so, it is a headache. Let’s try it out and see what it will be like if a mobile phone manufacturer uses a kind of charging cable. The Bluetooth mesh standard was born in the same way as Bluetooth was born. Before 2017, there were various own Bluetooth mesh standards at home and abroad. It was not until Sig released the official version that they were unified.
A solution created by Ericsson in 1994 to develop low-power, low-cost wireless communication connections between mobile phones and other accessories. The inventor hopes to create a unified set of rules (standardized protocol) for wireless communication between devices to solve the communication problem of mutually incompatible mobile electronic devices between users and to replace the RS-232 serial communication standard.
In December 1996, Ericsson, Nokia, Intel, Toshiba and IBM decided to establish a Special Interest Group (SpecialInterestGroup) to unify and maintain the wireless communication technology standard so that it can become the future wireless communication standard. After discussions, Intel was responsible for the development of semiconductor chips and transmission software, Ericsson was responsible for the development of wireless radio frequency and mobile phone software, and IBM and Toshiba were responsible for the development of notebook computer interface specifications.
On May 20, 1998, Ericsson joined forces with five well-known manufacturers: IBM, Intel, Nokia and Toshiba to establish the "Special Interest Group" (SIG), the predecessor of the Bluetooth Technology Alliance, with the goal of Develop a low-cost, high-efficiency Bluetooth technology standard that can be connected wirelessly at will within short distances. That year, Bluetooth launched the 0.7 specification, supporting two parts of the Baseband and LMP (Link Manager Protocol) communication protocols.
In 1999, version 0.8, version 0.9, and version 1.0 Draft were launched successively. Completed the SDP (Service Discovery Protocol) agreement and the TCS (Telephony Control Specification) agreement.
Version 1.0A was officially announced on July 26, 1999, and was determined to use the 2.4GHz frequency band. Compared with the popular infrared technology at the time, Bluetooth has a higher transmission speed and does not require interface-to-interface connections like infrared. Basically, all Bluetooth devices can be connected at any time as long as they are used within the effective communication range. Data can be exchanged at any angle and direction, which marks the beginning of the rapid development of Bluetooth technology.
In the second half of 1999, Apple, Microsoft, Motorola, Samsung, Lucent and five companies from the Bluetooth Task Force jointly initiated the establishment of the Bluetooth Technology Promotion Organization, thus setting off a global trend. The "Bluetooth" craze.
By April 2000, the SIG had more than 1,500 members and was growing faster than any other wireless alliance. As of now, more than 36,000 companies have become members of special interest groups. The latest version of the Bluetooth protocol is also 5.2, which was released on January 7, 2020. There is no news about Bluetooth 5.3 being released yet.
The first generation of Bluetooth: Early exploration of short-distance communication
1999: Bluetooth 1.0
There are multiple versions of early Bluetooth 1.0 A and 1.0B Problem, several manufacturers have pointed out that their products are incompatible with each other. At the same time, during the process of "linking" (Handshaking) between two devices, the address of the Bluetooth hardware (BD_ADDR) will be sent out. Anonymity cannot be achieved at the protocol level, causing the risk of data leakage.
Therefore, when version 1.0 was launched, Bluetooth was not immediately widely used. In addition to the small variety of electronic devices supporting Bluetooth functions at that time, Bluetooth devices were also very expensive.
2001: Bluetooth 1.1
Bluetooth version 1.1 is officially included in the IEEE 802.15.1 standard, which defines the physical layer (PHY) and media access control (MAC) specifications. For wireless connections between devices, the transmission rate is 748~810kb/s. However, because it is an early design, it is susceptible to interference from products of the same frequency, affecting communication quality.
2003: Bluetooth 1.2
Bluetooth version 1.2 also has a transmission rate of only 748~810kb/s, but in response to the security issues exposed by version 1.1, the anonymous method was improved. Added the function of blocking the hardware address of the device (BD_ADDR) to protect users from identity sniffing attacks and tracking, while being backward compatible with version 1.1.
In addition, four new functions have been added:
AFH (Adaptive Frequency Hopping) adaptive frequency hopping technology reduces interference problems between Bluetooth products and other wireless communication devices;
eSCO (Extended Synchronous Connection-Oriented links) extends synchronous connection-oriented channel technology to provide QoS audio transmission to further meet the needs of high-end voice and audio products;
Faster Connection function , which can shorten the time of re-searching and reconnecting, making the connection process more stable and faster;
Supports the transmission requirements of Stereo sound effects, but can only work in simplex mode.
The second generation of Bluetooth: EDR with high transmission rate
2004: Bluetooth 2.0
Bluetooth 2.0 is an improved version of version 1.2, with new EDR (Enhanced Data Rate) technology improves the ability of multi-tasking and simultaneous operation of multiple Bluetooth devices, making the transmission rate of Bluetooth devices approximately 1.8M/s ~ 2.1M/s.
Bluetooth 2.0 supports duplex mode: you can perform voice communication while transmitting documents/high-quality pictures. At the same time, EDR technology reduces power consumption by reducing workload cycles, and Bluetooth 2.0 increases the number of connected devices due to increased bandwidth.
The most widely used is the Bluetooth 2.0 EDR standard, which was launched in 2004. Products supporting the Bluetooth 2.0 EDR standard also appeared in large numbers in 2006. Although the Bluetooth 2.0 EDR standard has made a lot of technical improvements, the problems of complex configuration processes and high device power consumption inherited from the 1.X standard still exist.
Bluetooth 2.0 can be regarded as untimely: although Bluetooth 2.0 has appeared, most mobile phones still have integrated transmitters below Bluetooth 2.0, which has led to compatibility problems. Therefore, it is also There is no large-scale popularization; in addition, this is also the reason why Bluetooth is not easy for everyone to match.
2007: Bluetooth 2.1
Bluetooth 2.1 added the Sniff Subrating power saving function, which extended the signal sending interval for mutual confirmation between devices from 0.1 seconds in the old version to about 0.5 seconds. , thus greatly reducing the workload of the Bluetooth chip. In addition, the newly added SSP simple and secure pairing function improves the pairing experience of Bluetooth devices while enhancing the use and security strength. Supports NFC near field communication. As long as two Bluetooth devices with built-in NFC chips are brought close to each other, the pairing password will be transmitted through NFC without manual input.
On August 2, 2007, the Bluetooth Technology Alliance officially approved the Bluetooth version 2.1 specification, namely "Bluetooth 2.1 EDR", which can be freely used by future devices. At present, this version still occupies a large share of the Bluetooth market. Compared with version 2.0, it mainly improves the standby time by more than 2 times, and there is no fundamental change in the technical standards.
Many Bluetooth speakers on the market use this version of the standard for voice announcements after payment on mobile phones in the streets. Commonly referred to as audio Bluetooth, it supports SSP simple and secure pairing on Android, while MFI authentication is required on iOS.
The third generation of Bluetooth: High Speed, transmission rate up to 24Mbps
2009: Bluetooth 3.0
On April 21, 2009, the Bluetooth Technology Alliance officially promulgated Bluetooth Core specification version 3.0.
Bluetooth 3.0 adds the optional technology High Speed. High Speed ??allows Bluetooth to call 802.11 WiFi for high-speed data transmission. The transmission rate is up to 24Mbps, which is 8 times that of Bluetooth 2.0. It can easily realize the video recorder to HD TV, PC to PMP, UMPC Data transfer to and from the printer (both parties need to meet this standard to function).
The core of Bluetooth 3.0 is AMP (Generic Alternate MAC/PHY), a new alternate radio frequency technology that allows the Bluetooth protocol stack to dynamically select the correct radio frequency for any task.
In terms of power consumption, Bluetooth 3.0 introduces EPC enhanced power control technology, and supplemented by 802.11, the actual idle power consumption is significantly reduced.
The fourth generation of Bluetooth: focusing on "Low Energy" low power consumption
2010: Bluetooth 4.0
The Bluetooth 4.0 specification was officially launched on July 7, 2010 Released, the biggest significance of the new version lies in low power consumption, while enhancing device compatibility between different manufacturers and reducing latency. The theoretical maximum transmission speed is still 24Mbps (ie 3MB/s), and the effective coverage is expanded to 100 meters (previously version is 10 meters). With faster response times, the connection can be set up and data transferred in as little as 3 milliseconds. More secure technology, using AES-128 CCM encryption algorithm for packet encryption and authentication.
Bluetooth 4.0 is the first Bluetooth comprehensive protocol specification to date, integrating three specifications. The most important change is the BLE (Bluetooth Low Energy) low-power function, which proposes three modes: low-power Bluetooth, traditional Bluetooth and high-speed Bluetooth:
BLE was formerly Wibree technology developed by NOKIA. It is an extremely low-power mobile wireless communication technology developed specifically for mobile devices. It was renamed Bluetooth Low Energy (hereinafter referred to as Bluetooth Low Energy) after being accepted and standardized by SIG. These three protocol specifications can also be combined and matched with each other to achieve a wider range of application models.
The chip modes of Bluetooth 4.0 are divided into single mode and dual mode. Single mode can only transmit to and from Bluetooth 4.0 and is not backward compatible with version 3.0/2.1/2.0; Dual mode can be backward compatible with version 3.0/2.1/2.0. The former is used in sensor devices that use button batteries, such as heart rate detectors and thermometers that require high power consumption; the latter is used in traditional Bluetooth devices while taking into account low power consumption requirements.
2013: Bluetooth 4.1
Bluetooth 4.1 was released on December 6, 2013. If data is transmitted simultaneously with LTE radio signals, Bluetooth 4.1 can automatically coordinate the two. Transmitting information can theoretically reduce the interference of other signals on Bluetooth 4.1. The improvement is to increase the connection speed and make it more intelligent, such as reducing the reconnection time between devices, which means that if the user goes out of the Bluetooth 4.1 signal range and the disconnection time is not very long, when the user returns to the signal again The device will automatically connect after being in range, and the response time is shorter than Bluetooth 4.0. The last improvement is to improve transmission efficiency. If the user connects a lot of devices, such as multiple wearable devices, the information between each other can be sent to the receiving device instantly.
Bluetooth 4.1 has small changes in transmission speed and transmission range, but has significant improvements in software.
The purpose of this update is to make Bluetooth Smart technology eventually become the core driving force for the development of the Internet of Things (Internet of Things).
Allows developers and manufacturers to "customize" the reconnection interval of Bluetooth 4.1 devices, providing developers with greater flexibility and control.
Supports "Cloud Sync". Bluetooth 4.1 adds a dedicated IPv6 channel. Bluetooth 4.1 devices only need to be connected to devices that can connect to the Internet (such as mobile phones), and they can synchronize data with the cloud through IPv6 to meet the application needs of the Internet of Things.
Supports role interchange between "expansion device" and "central device". Headphones, watches, keyboards and mice that support the Bluetooth 4.1 standard can send and receive data independently without going through data hubs such as PCs, tablets, and mobile phones. For example, smart watches and pedometers can bypass smartphones and enable conversations directly.
2014: Bluetooth 4.2
On December 4, 2014, the latest Bluetooth 4.2 standard was released. The announcement of the Bluetooth 4.2 standard not only improves data transmission speed and privacy protection, but also allows the device to directly access the Internet through IPv6 and 6LoWPAN.
First of all, the speed becomes faster. Although the Bluetooth 4.1 version has improved a lot on the previous basis, it is far from meeting the needs of users. Compared with Wi-Fi, it appears to have insufficient advantages. The Bluetooth 4.2 standard has improved the capacity (MTU Size) of Bluetooth Smart data packets. The amount of data it can accommodate is about 10 times that of the previous one, and the data transmission speed between two Bluetooth devices has increased by 2.5 times.
Secondly, the enhanced privacy protection has also been praised by many users. We know that Bluetooth 4.1 and its previous versions have certain privacy risks - after connecting once, it automatically connects without further confirmation, which can easily cause privacy leaks. Under the new Bluetooth 4.2 standard, Bluetooth signals that want to connect or track user devices must obtain user permission, otherwise Bluetooth signals will not be able to connect and track user devices.
Of course, the most anticipated feature is the new version’s ability to access the Internet through IPv6 and 6LoWPAN. As early as Bluetooth version 4.1, the Bluetooth Technology Alliance has already begun to try to access, but due to the transmission rate limitations of previous versions and the incompatibility of the network chip, this function has not been fully implemented. According to the Bluetooth Technology Alliance, the new Bluetooth 4.2 standard can directly access the Internet through IPv6 and 6LoWPAN. I believe that on this basis, once IPv6 and 6LoWPAN can be widely used, this feature will attract more attention.
It must also be mentioned that for older Bluetooth adapters, some functions of Bluetooth 4.2 will be available through software upgrades, but not all functions will be available. The Bluetooth SIG said: "Privacy features may be available through firmware upgrades, subject to installation and enablement by the manufacturer. Speed ??improvements and packet expansion will require hardware upgrades."
So far, Bluetooth 4.0 is still the most commonly used standard for consumer devices, but mobile platforms such as Android Lollipop have begun to add native support for the Bluetooth 4.1 standard and Bluetooth 4.2 standard.
The fifth generation of Bluetooth: opening the door to the "Internet of Things" era
2016: Bluetooth 5.0
June 16, 2016, US time, Bluetooth Technology Alliance (SIG) officially released the fifth generation of Bluetooth technology (Bluetooth 5.0 for short) in Washington. Bluetooth 5.0 has faster and farther transmission capabilities in low-power mode. The transmission rate is twice that of Bluetooth 4.2 (the speed limit is 2Mbps), and the effective transmission distance is four times that of Bluetooth 4.2 (theoretically up to 300 meters). The data packet capacity is eight times that of Bluetooth 4.2.
Supports indoor positioning and navigation functions, and combined with WiFi can achieve indoor positioning with an accuracy of less than 1 meter.
In addition, Bluetooth 5.0 also allows receiving beacon data without pairing, such as advertisements, Beacons, location information, etc. At the same time, the Bluetooth 5.0 standard also performs underlying optimization for the IoT Internet of Things, making it faster and more power-saving, striving to serve smart homes with lower power consumption and higher performance.
In 2019, SIG launched Bluetooth 5.1. The new direction-finding function improves the accuracy of Bluetooth positioning to centimeter level, with lower power consumption, faster transmission, longer distance, and more accurate positioning.
In January 2020, the Bluetooth Technology Alliance released its new generation of Bluetooth audio technology standard - low-power audio LE Audio at CES2020 in Las Vegas. This solution has attracted attention with the outbreak of TWS headsets. Therefore, some insiders believe that the LE Audio Bluetooth standard will once again have a significant impact on terminal applications.
Mesh mesh network: the key "key" to realize the Internet of Things
The Bluetooth Technology Alliance officially announced on July 19, 2017 that Bluetooth (Bluetooth@) technology began to fully support Mesh Mesh network. Mesh mesh network is an independently developed network technology that can use Bluetooth devices as signal relay stations to cover data to a very large physical area and is compatible with Bluetooth 4 and 5 series protocols.
Traditional Bluetooth connections are achieved through "pairing" from one device to another, establishing a "one-to-one" or "one-to-many" micro-network relationship.
The Mesh network enables devices to achieve a "many-to-many" relationship. Each device node in the Mesh network can send and receive information. As long as a device is connected to the gateway, the information can be relayed between nodes, allowing the message to be transmitted farther than the normal transmission distance of radio waves.
In this way, Mesh networks can be distributed in manufacturing factories, office buildings, shopping malls, business parks, and wider scenarios to provide lighting equipment, industrial automation equipment, security cameras, smoke detectors, and environmental sensors. Provides a more stable control scheme.
Internet of Things: The new home of future Bluetooth technology
Since 1998, the Bluetooth protocol has been updated many times, from audio transmission, image and text transmission, video transmission, to Low power consumption is the main focus of IoT data transmission. On the one hand, backward compatibility of Bluetooth devices is maintained, and on the other hand, Bluetooth is also being used in more and more Internet of Things devices.
As the Low Energy version of Bluetooth continues to improve in power consumption and transmission efficiency, the Classic version (classic Bluetooth, or audio Bluetooth) has not been updated much since 3.0. It is foreseeable that the main focus of Bluetooth in the future will be on the Internet of Things, not just mobile devices. The addition of Mesh mesh networks makes it possible for Bluetooth to form its own IoT system.
According to SIG's market report, global Bluetooth device shipments will reach 4 billion by the end of 2018, of which: mobile phones, tablets and PCs will be shipped 2 billion this year, audio and entertainment Device shipments can reach 1.2 billion, 86% of the cars manufactured worldwide will be equipped with Bluetooth functions, and smart home Bluetooth device shipments can reach 650 million. Smart buildings, smart cities, smart industries, etc. will all become potential tracks in the future.
With the emergence of Bluetooth 5 technology and the maturity of Bluetooth mesh technology, the threshold for long-distance and multi-device communication between devices has been greatly reduced, bringing greater imagination to the future IoT. This technology, which came out 20 years ago, will continue to flourish in the future.
Wireless communication technology is the basis of today's network communications. According to distance, it can be divided into short-range wireless communication and long-distance wireless communication. Short-range wireless communication includes WIFI, Bluetooth, ZigBee, Z-Wave, NFC, UWB, etc. Long-distance wireless communication includes LoRa, NB-IoT, etc.
Compared with other wireless technologies: infrared, wireless 2.4G, and WiFi, Bluetooth has many advantages such as complete encryption measures, stable transmission process, and rich compatible devices. Especially today as the authorization threshold is gradually lowered, Bluetooth technology has begun to truly spread to all digital devices. However, Bluetooth has not been perfect along the way. From 1.0 to 5.0 is an extraordinary process.
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