Bluetooth has evolved through five versions from 1.0 to 5.0, each with distinct features. As the version number increases, the functionality of Bluetooth has continuously improved. This article introduces the Bluetooth standards from 1.0 to 5.0, the changes in transmission speed, the increase in effective transmission distance, changes in communication modes, and functional improvements.
Version 1.0
The transmission rate is approximately 748~810 kb/s. As an early design, it is easily affected by interference from similar communication products operating on the same frequency, impacting communication quality. This initial version supports the transmission requirements for Stereo sound but can only operate in (half-duplex) mode, and with unsatisfactory bandwidth frequency response and other indicators, it is not considered the best tool for Stereo transmission.
Version 1.2
It also has a transmission rate of only 748~810 kb/s but adds anti-interference frequency hopping functionality; technical theories are not elaborated here. It supports the transmission requirements for stereo sound but can only operate in half-duplex mode, and the bandwidth frequency response is still unsatisfactory, thus it cannot serve as a tool for stereo transmission.
Version 2.0
2.0 is an improved version of 1.2, with a transmission rate of approximately 1.8 M/s to 2.1 M/s, allowing for full-duplex operation. This means that while voice communication occurs, files/high-quality images can also be transmitted. Version 2.0 naturally supports Stereo operation. Subsequent Bluetooth 2.0 chips added Stereo decoding chips, making A2DP (Advanced Audio Distribution Profile) unnecessary.
Version 2.1
To improve the issues present in Bluetooth technology, the Bluetooth SIG (Special Interest Group) introduced the Bluetooth 2.1+EDR version of Bluetooth technology.
Improved device pairing process: Previously, during the connection process, a personal identification code was needed to ensure connection security. The improved connection method automatically uses a digital password for pairing and connection. For example, by selecting a specific device in the phone options, the phone will automatically list available devices in the current environment and connect automatically; the short-range pairing aspect also includes an NFC mechanism for mutual pairing and communication transmission between two Bluetooth-enabled phones; better power-saving effects: Bluetooth 2.1 introduced the Sniff Subtracting feature, which saves power by confirming the signal sending interval between two devices.
Bluetooth 2.1 extends the signal sending time interval between devices from the old version’s 0.1 seconds to about 0.5 seconds, significantly reducing the workload on Bluetooth chips and allowing Bluetooth to have more time to enter deep sleep. According to official reports, after adopting this technology, the standby time of Bluetooth devices can be effectively extended by more than five times, supporting full-duplex communication mode.
Version 3.0+HS
On April 21, 2009, the Bluetooth Special Interest Group (Bluetooth SIG) officially issued the new generation standard specification “Bluetooth Core Specification Version 3.0 High Speed”.
The core of Bluetooth 3.0 is the “Generic Alternate MAC/PHY” (AMP), a new alternating radio frequency technology that allows the Bluetooth protocol stack to dynamically select the correct radio frequency for previous tasks. Initially, technologies expected to be used in the new specification included 802.11 and UMB, but UMB’s application was removed in the new specification. As a new version, Bluetooth 3.0 naturally offers higher transmission speeds, with the secret lying in the 802.11 wireless protocol. By integrating “802.11PAL” (Protocol Adaptation Layer), Bluetooth 3.0’s data transmission rate increased to about 24 Mbps (allowing 802.11 WI-FI to be called upon for high-speed data transmission when needed), which is eight times that of Bluetooth 2.0, easily facilitating data transfer between camcorders and HD TVs, PCs and PMPs, and UMPCs and printers.
In terms of power consumption, Bluetooth 3.0’s high-speed data transmission naturally consumes more energy, but the introduction of the Enhanced Power Control (EPC) mechanism, along with 802.11, significantly reduces actual idle power consumption, potentially solving the standby power consumption issues of Bluetooth devices.
Additionally, the new specification includes General Testing Method (GTM) and Unidirectional Broadcast Unconnected Data (UCD) technologies, along with a set of HCI commands to obtain key lengths. It is claimed that PCs equipped with Bluetooth 2.1 modules can theoretically support Bluetooth 3.0 by upgrading firmware. Alliance members have begun to develop Bluetooth 3.0 solutions for device manufacturers.
Version 4.0
Bluetooth 4.0 is an upgraded standard of Bluetooth 3.0. The most important feature of Bluetooth 4.0 is power saving, with extremely low operating and standby power consumption allowing a button battery to work continuously for several years. Moreover, low cost and cross-vendor interoperability, 3 ms low latency, AES-128 encryption, and many other features can be used in pedometers, heart rate monitors, smart meters, sensor IoT, and many other areas, greatly expanding the application scope of Bluetooth technology.
Bluetooth 4.0 supplements the Bluetooth 3.0+HS specification, specifically targeting wireless solutions with high demands for cost and power consumption, and can be widely used in healthcare, sports fitness, home entertainment, security, and many other fields. It supports two deployment modes: dual-mode and single-mode.
In dual-mode, low-power Bluetooth functionality is integrated into existing classic Bluetooth controllers or by adding a low-power stack on existing classic Bluetooth technology (2.1+EDR/3.0+HS) chips, keeping the overall architecture largely unchanged, thus increasing costs minimally. Single mode can only transmit with BT4.0 and is not backward compatible (cannot communicate with 3.0/2.1/2.0); Dual mode can be backward compatible, transmitting with BT4.0 as well as with 3.0/2.1/2.0.
Single mode targets highly integrated, compact devices, using a lightweight connection layer (Link Layer) to provide ultra-low power standby mode operation, simple device recovery, and reliable point-to-multipoint data transmission. It also allows connected sensors to arrange low-power Bluetooth traffic in transmission while providing advanced energy-saving and secure encrypted connections.
Bluetooth 4.0 integrates three specifications, including traditional Bluetooth technology, high-speed technology, and low-energy technology, with the most significant difference from version 3.0 being low power consumption. The power consumption of version 4.0 is reduced by 90% compared to older versions, making it more energy-efficient. As Bluetooth technology expands from traditional application areas like mobile phones, gaming, headsets, portable computers, and automobiles to new areas like IoT and healthcare, the demand for low power consumption will continue to rise. Version 4.0 enhances Bluetooth’s low power performance in data transmission.
Version 4.1
If Bluetooth 4.0 focuses on power-saving features, then the keyword for the upgrade to Bluetooth 4.1 should be IoT (Internet of Things), meaning that all devices are interconnected. To achieve this, improvements to communication functionality are one of the most important advancements in Bluetooth 4.1.
(1) Bulk data transmission speed
First and foremost is the bulk data transmission speed. Bluetooth’s transmission rate has always been poor compared to Wi-Fi, which has already reached gigabit speeds. Therefore, Bluetooth 4.1 has been upgraded on the widely used Bluetooth 4.0 LE basis, allowing bulk data to be transmitted at higher speeds.
Of course, this does not mean that Bluetooth can be used for high-speed streaming video transmission; this improvement primarily targets the newly emerging wearable devices. For example, the already common health bands send out small data streams, and Bluetooth 4.1 can transmit information collected during running, swimming, or cycling to mobile devices more quickly, allowing users to better monitor their exercise status in real-time, which is very useful.
In the Bluetooth 4.0 era, all devices using Bluetooth 4.0 LE were labeled as “Bluetooth Smart” and “Bluetooth Smart Ready.” Bluetooth Smart Ready devices refer to connection center devices like PCs, tablets, and phones, while Bluetooth Smart devices refer to Bluetooth headsets, keyboards, and mice. Previously, the roles between these devices were predetermined and could not be switched; they could only connect one-to-one. However, in Bluetooth 4.1 technology, devices are allowed to simultaneously act as both “Bluetooth Smart” and “Bluetooth Smart Ready,” meaning multiple devices can connect to one Bluetooth device. For example, a smart watch can act as a central hub, receiving exercise information collected from a health band while also serving as a display device for emails and messages from a smartphone. With Bluetooth 4.1 technology, smart watches, smart glasses, and other devices can become real central hubs.
(2) Connecting to the internet via IPV6
Additionally, the problem of wearable devices accessing the internet can also be solved through Bluetooth 4.1. The new standard adds a dedicated channel allowing devices to connect to the internet using IPv6. For instance, if a Bluetooth device cannot access the internet, it can connect to another device that can access the internet via Bluetooth 4.1, allowing it to directly use IPv6 to connect to the internet, achieving the same functionality as Wi-Fi. Although the application of internet access is limited due to transmission rate constraints, operations like data synchronization and email sending and receiving can be fully realized. The advantage of this improvement is that sensors and embedded devices can connect to mobile phones and the internet using only Bluetooth, whereas Wi-Fi is generally used for internet connections and is less effective for connecting devices, unable to achieve the functionality of Bluetooth. As the Internet of Things gradually enters our lives, wireless transmission will play an increasingly important role in daily life, with Bluetooth, as the most widely used transmission method, playing an irreplaceable role in the “Internet of Things.” However, complete adaptation of Bluetooth to IPv6 will take longer, so it will depend on how chip manufacturers help Bluetooth devices increase IPv6 compatibility.
(3) Simplifying device connections
With the push from major mobile device and PC manufacturers, almost all mobile devices and laptops are equipped with Bluetooth modules, and users are quite familiar with Bluetooth usage. However, many users still find Bluetooth cumbersome to use, primarily due to the complex pairing and connection processes of Bluetooth devices. For instance, if a smart watch connected to a phone disconnects, it can be very inconvenient to manually select it again in the settings to reconnect. Previously, the solution to this problem was for manufacturers to include NFC chips in both Bluetooth devices, simplifying the re-pairing process through NFC near-field communication. This was a good idea, but the number of products equipped with NFC chips is limited, and they tend to be expensive and niche.
Bluetooth 4.1 has made significant improvements in this regard, greatly modifying the connection and reconnection processes between devices, allowing manufacturers more design flexibility, including setting frequency bands to create or maintain Bluetooth connections. This change significantly enhances the flexibility of Bluetooth device connections. If two devices equipped with Bluetooth 4.1 have successfully paired before, they can reconnect simply by bringing them close together, without any manual operation required. For example, in the future, when using Bluetooth 4.1 headphones, simply turning on the power switch will suffice, without needing to perform any operations on the phone, making it very simple.
In the field of mobile communications, the hottest topic recently has been 4G, which has become an irreversible trend in global wireless communication networks. Bluetooth 4.1 has also been optimized specifically for 4G to ensure coexistence with 4G signals, a change referred to as “coexistence” by the Bluetooth technology alliance. Some may wonder why Bluetooth 4.1 needs to improve this aspect when Bluetooth and mobile network signals have coexisted for so long.
This is because in practical applications, if both transmit data simultaneously, Bluetooth communication may be affected by mobile network signals, leading to a decrease in transmission rates. Therefore, in the new Bluetooth 4.1 standard, when both Bluetooth 4.1 and 4G networks are transmitting data simultaneously, Bluetooth 4.1 will automatically coordinate the transmission information of both, thereby reducing interference from other signals on Bluetooth 4.1, relieving users of concerns about transmission rate drops.
(4) Enhanced features provided by Bluetooth 4.1
AES encryption technology provides a more secure connection. This feature makes wireless headphones more suitable for applications in government, healthcare, and banking where security is paramount. It allows for remote control of headphones, speakers, and soundbars via dedicated Bluetooth Smart remote controls and supports synchronized playback of audio streams originating from entirely different devices.
Version 4.2
On December 4, 2014, the Bluetooth 4.2 standard was issued, improving data transmission speed and privacy protection, allowing direct access to the internet via IPv6 and 6LoWPAN. Under the new standard, Bluetooth signals must obtain user permission to connect or track user devices; otherwise, Bluetooth signals will not be able to connect and track user devices.
In terms of speed, data transmission speed between two Bluetooth devices has increased by 2.5 times, as the capacity of Bluetooth Smart data packets has increased, accommodating roughly ten times the amount of data previously.
Version 5.0
(1) Faster transmission speeds
Developers of Bluetooth 5.0 claim that the new version’s maximum transmission speed is 2 Mbps, which is twice that of the previous 4.2LE version. Of course, it is unlikely that this maximum speed will be achieved in real life, but users can still experience a significant speed increase.
(2) Greater effective distance
Another important improvement of Bluetooth 5.0 is that its effective distance is four times that of the previous version. Theoretically, the effective working distance between Bluetooth transmitting and receiving devices can reach up to 300 meters.
(3) Navigation functionality
Bluetooth 5.0 will add more navigation functionalities, allowing the technology to serve as indoor navigation beacons or similar positioning devices, achieving indoor positioning with an accuracy of less than 1 meter in conjunction with Wi-Fi.
(4) IoT capabilities
Bluetooth 5.0 has undergone many foundational optimizations for the Internet of Things, striving to serve smart homes with lower power consumption and higher performance.
(5) Upgraded hardware
Previous Bluetooth version updates only required software upgrades, but Bluetooth 5.0 will likely require new chip upgrades. However, older hardware can still be compatible with Bluetooth 5.0, though it will not be able to utilize its new features.
(6) More transmission functionalities
The new Bluetooth 5.0 can add more data transmission functionalities, allowing hardware manufacturers to create more complex connection systems, such as Beacons or location services. Thus, advertising data sent via Bluetooth devices can transmit small amounts of information to target devices without needing to pair.
(7) Lower power consumption
It is well-known that Bluetooth is an essential feature of smartphones, and as more smart devices and mobile payment options require Bluetooth to enjoy convenient features, Bluetooth’s power consumption has become a significant factor affecting smartphone standby time. Therefore, Bluetooth 5.0 will significantly reduce Bluetooth’s power consumption, alleviating concerns about short standby times during Bluetooth use.
(8) True lossless transmission support
Supports 24bit/192KHz lossless audio source transmission, posing a significant threat to existing Wi-Fi high-fidelity lossless audio transmission.
The above is an introduction to the features of different Bluetooth versions. In the future, Bluetooth technology will integrate better with other wireless connection technologies, and its application range will be broader.
——This article is reprinted from Electronic Product World——
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