During World War II, Hollywood actress Hedy Lamarr, who should have relied on her beauty to make a living, instead relied on her strength to join forces with pianist George Antheil to study Frequency Hopping Spread Spectrum (FHSS) technology. According to relevant records, this technology was patented in August 1942. For nearly half a century, this technology was not taken seriously. It was not until the 1980s that FHSS technology was used by the military for wireless communication systems on the battlefield. Later, FHSS technology sank to the mass market, and also affected the development of wireless technologies such as Bluetooth and WiFi.
Time has changed, and the Bluetooth technology based on FHSS has also undergone tremendous changes - its standard has been upgraded from Bluetooth 1.0 to Bluetooth 5.0 to LE Audio. In the process of this technological change , what has Bluetooth changed?
The origin of Bluetooth technology
Bluetooth technology can be traced back to 1994. At the beginning, Ericsson devoted itself to the research of Bluetooth technology as an alternative to RS-232 data lines. . RS-232 is one of the commonly used serial communication interface standards. It was jointly formulated in 1970 by the Electronic Industries Association (EIA), Bell Systems, modem manufacturers and computer terminal manufacturers. The RS-232 bus specifies 25 lines and includes two signal channels, namely the first channel (called the main channel) and the second channel (called the secondary channel). RS-232 uses a point-to-point connection, and usually a serial port can only connect to one peripheral. Using Bluetooth technology, multiple devices can be connected, thereby overcoming the problem of data synchronization. Therefore, Bluetooth technology is regarded as a method for low-power, low-cost wireless communication connections between mobile phones and other accessories.
In 1997, Ericsson used this concept to contact mobile device manufacturers to discuss their project cooperation and development and obtain support. In 1998, five companies including Ericsson, Nokia, Toshiba, IBM and Intel established the "Special Interest Group" (SIG), the predecessor of the Bluetooth Technology Alliance, with the goal of developing a low-cost, high-efficiency , a Bluetooth technology standard that can be connected wirelessly at will within a short distance. During this time, an interesting thing happened regarding the naming of Bluetooth. At that time, SIG's contract framework was nearly completed, but the official name of this short-term wireless connection technology had not yet been determined. Its alternative name, PAN, was biased towards buzzwords and already had high traffic in Internet search engines at the time. Therefore, the trademark search failed. Intel's Jim Kardach suggested using Bluetooth as an interim codename. Kardach was later quoted as saying: "King Harald Bluetooth, is known for uniting Scandinavia, just as we intend to unite the PC and cellular industries through short-range wireless links."
Version 0.7 is the first standard version of Bluetooth, which supports Baseband and LMP communication protocols. Then, SIG was established and successively released Bluetooth version 0.8, version 0.9, version 1.0 Draft, version 1.0a and version 1.0B. In the second half of 1999, five companies including Microsoft, Motorola, Samsung, Lucent and the Bluetooth Task Force jointly initiated the establishment of a Bluetooth technology promotion organization, thus setting off a Bluetooth craze around the world.
The evolution of the Bluetooth standard promotes changes in terminal applications
Under the craze of Bluetooth, the Bluetooth standard has also changed along with the needs of technical terminal applications.
Bluetooth version 1.0, launched in 1999, was not widely used immediately because of technical data leakage problems. In addition, at that time, there were few types of electronic devices supporting Bluetooth functions, and Bluetooth devices were also very expensive, which was one of the reasons why Bluetooth was not widely adopted. It was not until 2001 that Bluetooth 1.1 became the first official commercial version and entered the market. This version of the Bluetooth standard has also been officially included in the IEEE standard, also known as IEEE 802.15.1. In the same year, the number of SIG member companies exceeded 2,000.
After a few years, Bluetooth has become an essential feature of electronic products, and its price has dropped significantly due to the maturity of the technology. In order to expand the application level and transmission speed of Bluetooth, SIG successively launched version 1.2 (in order to solve the problem of being prone to interference, this version added an anti-interference frequency hopping function) and version 2.0 in 2003 and 2004, and added many new features. Function. According to Wikipedia information, version 2.0 has added features such as EDR (Enhanced Data Rate, which increases the maximum transmission speed to 3Mbps in accordance with the technical standards of 2.0), A2DP (Advanced Audio Distribution Profile, a track distribution technology, which is mainly used in Stereo headphones), AVRCP (A/V Remote Control Profile), etc. Bluetooth 2.0 increases the transmission rate to 2Mbps and 3Mbps, which is much larger than the 1Mbps of version 1.x (actually about 723.2kbps). Bluetooth version 2.0 begins to support duplex mode-that is, it can perform voice communication on one side and transmit data at the same time. It was also from this version that Bluetooth was recognized by the market. Subsequently, in mid-2007, SIG made improvements to the existing problems and released Bluetooth version 2.1. At this time, the emergence of Bluetooth technology allowed mobile phones to transmit audio, video, and pictures to each other. But at that time, the method of connecting mobile phones through Bluetooth was relatively cumbersome. Both sides of the pairing displayed a 6-digit number. It was up to the user to check whether the numbers were consistent and input Yes/No. If both ends indicated yes, they could pair. Although this was cumbersome at the time, it could prevent man-in-the-middle attacks.
In 2009, Bluetooth 3.0 also began to enter the market, using a new alternative radio frequency technology and canceling UMB applications. In April this year, the Bluetooth Technology Alliance promulgated Bluetooth Core Specification Version 3.0 (3.0 +HS), which is a new alternative radio frequency technology. Bluetooth 3.0 +HS improves the data transmission rate, and the integrated 802.11PAL has a maximum speed of 24Mbps, which is 8 times the speed of Bluetooth 2.0. In addition, enhanced power control is introduced, and actual idle power consumption is significantly reduced. This feature also adds closed-loop power control, meaning RSSI filtering can be initiated at the same time as a reply is received. In addition, this version also adds a request to "go straight to max power" to deal with the link loss of the headset. Traditional Bluetooth headsets are also gradually entering the market.
In 2010, the release of Trinity Bluetooth 4.0 once again revolutionized Bluetooth technology. At the time of the release of this version, SIG also proposed three modes: "Bluetooth Low Energy", "Bluetooth Traditional" and "Bluetooth High Speed". Among them, high-speed Bluetooth focuses on data exchange and transmission; traditional Bluetooth focuses on information communication and device connection; Bluetooth low-power, as its name suggests, focuses on connecting devices that do not require too much bandwidth. The predecessor was actually Wibree technology developed by NOKIA. It was originally an extremely low-power mobile wireless communication technology developed specifically for mobile devices. After being accepted and standardized by SIG, it was renamed Bluetooth Low Energy (hereinafter referred to as Bluetooth Low Energy). ). These three protocol specifications can also be combined with each other to achieve a wider range of application modes. In addition, Bluetooth 4.0 also increases the transmission distance of Bluetooth to more than 100 meters (under low-power mode conditions). At this point, the release of Bluetooth 4.0 has also laid the foundation for the subsequent development of the Internet of Things.
Then, at the end of 2013, the Bluetooth Technology Alliance launched the Bluetooth 4.1 specification, whose purpose is to make Bluetooth Smart technology eventually become the core driving force for the development of the Internet of Things. This version improves support for LTE and bulk data exchange rate storage, and helps developers innovate by allowing devices to support multiple roles simultaneously. Through Bluetooth 4.1 version, headphones, watches, keyboards and mice that support this standard can independently send and receive data without going through data hubs such as PCs, tablets, and mobile phones. For example, smart watches and pedometers can bypass smartphones and enable direct conversations.
In 2014, SIG updated the Bluetooth standard and launched Bluetooth 4.2, which is not only 2.5 times faster and more private, but can also connect to the Internet through IPv6. This technology allows multiple Bluetooth devices to access the Internet or LAN through one terminal. In this way, most smart home products can abandon the relatively complicated WiFi connection and switch to Bluetooth transmission, making the interconnection between personal sensors and homes more convenient and faster.
In 2016, the Bluetooth standard continued to evolve with the explosion of Internet of Things applications. During this period, SIG released Bluetooth 5.0 version. Compared with Bluetooth 4.0 version, 5.0 has twice the transmission speed. The transmission distance is increased by four times, the data transmission volume is increased by eight times, and it can be stored with Wi-Fi without interfering with each other. In 2019, SIG launched Bluetooth 5.1, adding a new direction-finding function, which improved the accuracy of Bluetooth positioning to centimeter level, with lower power consumption, faster transmission, longer distance, and more accurate positioning. With the launch of the Bluetooth 5.1 standard, the industry has also seen the prospect of applying Bluetooth technology to indoor positioning, which is also one of the future development prospects of Bluetooth technology.
In addition, with the advent of the era of Internet of Everything, Bluetooth technology has also been absorbed and expanded. In addition to the Bluetooth 1, 2, 3, 4, and 5 series standards, the Bluetooth Technology Alliance officially announced in July 2017 that Bluetooth technology began to fully support Mesh mesh networks. It is reported that Bluetooth Mesh will be compatible with Bluetooth 4 and 5 series protocols. The new Mesh function provides many-to-many transmission between devices, and especially improves the communication capabilities of building large-scale network coverage. It is suitable for building automation, wireless sensor networks and other applications that require tens of thousands of devices to transmit in a reliable and secure environment. IoT solutions. With the launch of Bluetooth Mesh, smart homes have developed greatly, and this field is also regarded as another direction for the future development of Bluetooth. At the 2018 International Consumer Electronics Show, Alibaba and MediaTek announced that they would work together to promote Bluetooth Mesh technology, signed a cooperation agreement, and created the first Smartmesh wireless connection solution that supports Bluetooth Mesh technology.
The new Bluetooth standard will once again reform terminal applications
In January 2020, the Bluetooth Technology Alliance released its new generation of Bluetooth audio technology at CES2020 in Las Vegas Standard - low power audio LE Audio. 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 major impact on terminal applications.
As we all know, traditional Bluetooth headsets have not been widely used before because their sound quality and battery life are not satisfactory. TWS headphones that use the LE Audio Bluetooth standard can transmit better sound over longer distances with low energy consumption. According to the SIG official website, in terms of improving sound quality, the LE Audio Bluetooth standard includes a new high-quality, low-power audio codec, the Low Complexity Communication Codec (LC3). Delivering high quality even at low data rates, LC3 will bring tremendous flexibility to developers, allowing them to make better design tradeoffs between key product attributes such as audio quality and power consumption. According to relevant reports, the quality of LC3 has been improved by three times, while the energy consumption when transmitting audio has been reduced by three times.
According to relevant reports, SIG will launch independent functions of LE Audio this year. SIG expects chip manufacturers to release new designs that support LE Audio within next year to 18 months. This is because LE Audio requires the mobile phone to support the LE Audio standard before TWS headphones make more sense. Therefore, in this case, TWS headsets are still some distance away from their real explosive period.
At the same time, SIG also introduced on its official website that LE Audio will not only bring development opportunities to TWS headphones, but this standard will also promote the development of other audio products. For example, LE Audio will advance the development of Bluetooth hearing aids, bringing all the benefits of Bluetooth audio to the growing number of people with hearing loss. LE Audio will also add broadcast audio, allowing an audio source device to broadcast one or more audio streams to an unlimited number of audio sink devices.
Broadcast audio offers significant new opportunities for innovation, including enabling new Bluetooth use cases called Audio Sharing. Bluetooth audio sharing can be personal or location-based. With Personal Audio Sharing, people will be able to share their Bluetooth audio experience with others around them; for example, sharing music from their smartphones with family and friends. With location-based audio sharing, public venues such as airports, bars, stadiums, movie theaters and conference centers can now share Bluetooth audio to enhance the visitor experience.
Conclusion
The above data shows that Bluetooth has evolved from the initial audio transmission, image and text transmission, and video transmission to become the protagonist of IoT transmission. Especially in the past year, the development of Bluetooth technology has also led to changes in the TWS headset market. Judging from the changes in Bluetooth technology, its development has a huge impact on downstream terminal products. In recent years, the diversification trend of terminal products has also brought new opportunities for the development of Bluetooth.
At the same time, as a member of wireless communications, Bluetooth technology also needs to compete with other wireless transmission technologies such as WiFi. How Bluetooth technology maintains its advantage in this competition is worthy of the industry's attention.