Short link broadcast technology (later renamed Bluetooth) was originally developed by Nils Rydbeck, CTO of Ericsson Mobile, in Lund, Sweden, for the purpose of using two inventions published in 1989 (Dr. Johan Ullman SE 8902098-6 released on June 2, 1989 and SE 9202239 released on July 24, 1992), to develop a wireless headset. Nils Rydbeck left the specification work to Tord Wingren and the development work to Jaap Haartsen and Sven Mattisson. They work for Ericsson in Lund, Sweden. This specification is based on frequency hopping technology.
The Bluetooth specification was officially launched by the Bluetooth Technology Alliance, which was officially announced on May 20, 1998. Today it has more than 25,000 member companies worldwide. It was originally founded by Ericsson, IBM, Intel, Toshiba and Nokia, and was later joined by many other companies.
All Bluetooth standard versions support backward compatibility, allowing the latest version to cover all older versions.
The Bluetooth Core Specification Working Group (CSWG) mainly develops 4 specifications of Bluetooth core specifications. The Core Specification Appendix (CSA) is usually updated every few years, and the core can be updated several times a year. Specification Supplement (CSS), Release of Faster Errata This Bluetooth core version was released in 2004. The main difference is the introduction of Enhanced Data Rate (EDR), which enables faster data transfer. The nominal rate of EDR is 3 Mbit/s, although the actual data transfer rate is 2.1 Mbit/s. EDR uses a combination of GFSK, Phase Shift Keying (PSK) modulation and π/4-DQPSK, 8DPSK variables. EDR provides lower power consumption by reducing duty cycles.
This specification is named Bluetooth v2.0 EDR, which means that EDR is an optional function. In addition to EDR, the 2.0 specification includes other minor improvements. Products do not need to support higher-speed data rates to complete Bluetooth 2.0 compliance certification. At least one commercial device states on its data sheet that it is "Bluetooth 2.0 without EDR support." Bluetooth Core Specification 2.1 EDR was launched by the Bluetooth Technology Alliance on July 26, 2007.
The biggest feature of 2.1 is Secure Simple Pairing (SSP): it improves the pairing experience for Bluetooth devices, while also improving the practical application and strength of security. Please refer to the "Pairing" section below for more details.
2.1 also includes other improvements, including "Extended Inquiry Response" (EIR), which provides more information during the query process so that devices can better filter before connecting; and low battery consumption like Sniff Subrating, which can reduce power consumption in low-power mode. The Bluetooth core specification 3.0 HS version was launched by the Bluetooth Technology Alliance on April 21, 2009. Bluetooth 3.0 HS can theoretically achieve transfer rates of up to 24 Mbit/s, although this is not through the Bluetooth link itself. Instead, the Bluetooth link is used for negotiation and establishment, and high-speed data transfer is completed by the co-located 802.11 link.
The main new feature is AMP (Alternative MAC/PHY), which is also a new high-speed transmission function of 802.11. High speed is not a mandatory feature of this specification, so only devices marked with the HS trademark truly support Bluetooth through 802.11 high-speed data transmission. Bluetooth 3.0 devices not marked with the HS suffix only support core specification version 3.0 or the previous core specification Appendix 1.
L2CAP Enhanced Mode
Enhanced Retransmission Mode (ERTM) uses a reliable L2CAP channel, while Streaming Mode (SM) uses It is an unreliable network channel without retransmission and flow control. Introduced in Appendix 1 of the core specification.
Alternative MAC/PHY
Bluetooth profile data can be transmitted via alternative MAC and PHYs. The Bluetooth radio is still used for device discovery, initial connection, and profile configuration. But when there is a need for large amounts of data transfer, the high-speed alternative MAC PHY 802.11 (often associated with Wi-Fi) can transfer the data. This means Bluetooth can use its proven low-power connection model when the system is idle, using a faster radio when large amounts of data need to be transferred. AMP links require enhanced L2CAP mode.
Unicast Connectionless Data (Unicast Connectionless Data)
Unicast Connectionless Data can transmit service data without establishing an explicit L2CAP channel. Mainly used for applications that require low latency for user operations and data reconnection/transmission. It is only suitable for small amounts of data transfer.
Enhanced Power Control
Enhanced Power Control updates the power control function, removes open-loop power control, and clarifies the new modulation method of EDR. Introduced power control. Enhanced power control specifies the desired behavior. This feature also adds closed-loop power control, meaning RSSI filtering can be initiated at the same time as a reply is received. Additionally, a "go straight to maximum power" request was introduced to combat headset link loss, especially when the user puts the phone in a pocket on the opposite side of the body.
Ultra-wideband
The high-speed (AMP) features of Bluetooth 3.0 were originally intended for UWB applications, but the WiMedia Alliance (WiMedia Alliance) is responsible for the UWB features of Bluetooth. organization) announced its dissolution in March 2009, and UWB was eventually eliminated from the core specification version 3.0.
On March 16, 2009, the WiMedia Alliance announced that they had entered into discussions on the technology transfer agreement for the WiMedia Ultra-Wideband (UWB) version. WiMedia has transferred all current and future versions to the Bluetooth SIG, Wireless USB Promoter Group, and USB Implementers Forum, including future high-speed and power optimization and other related work. After the successful completion of technology transfer, marketing and related administrative terms, the WiMedia Alliance ceased operations.
In October 2009, the Bluetooth SIG suspended the development of UWB as part of the Bluetooth 3.0 HS alternative MAC/PHY solution. Because a few but important members of the former WiMedia were unwilling to sign the necessary agreements for IP transfer. The Bluetooth SIG is now evaluating other options for its long-term growth. See also: Bluetooth Low Energy
The Bluetooth SIG officially launched Bluetooth Core Specification 4.0 (called Bluetooth Smart) on June 30, 2010. It includes Bluetooth Classic, Bluetooth High Speed ??and Bluetooth Low Energy protocols. High Speed ??Bluetooth is based on Wi-Fi, while Classic Bluetooth includes older Bluetooth protocols.
Bluetooth Low Energy, also known as Wibree earlier, is a subset of Bluetooth version 4.0. It has a new protocol stack and can quickly establish simple links.
As an alternative to the Bluetooth standard protocol in Bluetooth 1.0 – 3.0 versions, it is mainly targeted at applications that require extremely low power consumption and are powered by button batteries. Chip designs are available in two flavors: dual-mode, single-mode and enhanced early versions. The early names Wibree and Bluetooth ULP (Ultra Low Power) were deprecated and replaced by the later BLE. Later in 2011, new trademarks were launched, namely "Bluetooth Smart Ready" for the main device and "Bluetooth Smart" for the sensor. In the case of single mode, only low-power protocol stacks can be executed. STMicroelectronics, Shengke Electronics, CSR, Nordic Semiconductor and Texas Instruments have released single-mode Bluetooth low energy solutions. In the dual-mode case, the Bluetooth Smart function is integrated into the existing classic Bluetooth controller. As of March 2011, Qualcomm Atheros, CSR, Broadcom and Texas Instruments have announced the release of chips that comply with this standard. The applicable architecture enjoys all the existing radio frequencies and functions of classic Bluetooth, and the price increase compared to classic Bluetooth is almost negligible. The cost reduction of single-mode chips makes it possible to achieve a high degree of integration and compatibility of equipment. One of its features is a lightweight link layer that provides low-power idle mode operation, easy device discovery, and reliable point-to-multiple data transfer, with advanced power-saving and secure encrypted connections at a very low cost.
General improvements in version 4.0 include those necessary to advance Bluetooth Low Energy mode, as well as the Generic Attribute Profile (GATT) and AES-encrypted Security Manager (SM) services.
Core Specification Appendix 2 was officially launched in December 2011. It includes improvements to the audio host controller interface and high-speed (802.11) protocol adaptation layer.
Core Specification Appendix 3 Revision 2 was officially adopted on July 24, 2012.
Core Specification Appendix 4 was officially adopted on February 12, 2013. The Bluetooth Technology Alliance officially announced the adoption of Bluetooth core specification version 4.1 in December 2013. This specification is a software update to Bluetooth version 4.2, not a hardware update. This update includes the Bluetooth Core Specification Addenda (CSA1, 2, 3 and 4) and adds new features to improve consumer usability. These features include improved support for LTE and bulk data exchange rate storage, and help developers innovate by allowing devices to support multiple roles simultaneously.
The features of version 4.1 are as follows: Mobile Wireless Service ***Signaling Train nudging and universal interface scanning Low duty cycle directional broadcast Credit-based flow control L2CAP Connection-oriented dedicated channel Dual-mode and topology Low power Consumed link layer topology 802.11n PAL Audio architecture updates for wideband voice Fast Data Advertising Interval Limited discovery time Please note that some features existed in the Core Specification Addendum (CSA) prior to version 4.1 .
Bluetooth 4.2 was released on December 2, 2014. It introduces some key features for IoT and is a hardware update. However, some old Bluetooth hardware can also obtain some features of Bluetooth 4.2, such as privacy protection updates through firmware.
The main improvements are as follows: Low-power packet length extension Low-power secure connection Link layer privacy permissions Link layer extended scanning filtering policy Bluetooth Smart devices can support profiles through network protocols (Internet Protocol Support Profile (IPSP for short) to implement IP connections. IPSP adds an IPv6 connectivity option to Bluetooth Smart, ideal for connected home and IoT applications. Bluetooth 4.2 makes data transmission faster by increasing the packaging capacity of Bluetooth Smart.
Industry-leading privacy settings make Bluetooth Smart smarter. Not only does it reduce power consumption, it also makes it difficult for eavesdroppers to track the device online via Bluetooth. Consumers can be more assured that they will not be tracked by beacons and other devices. Benefits of this core release include: Enabling the Internet of Things: Support for flexible Internet connectivity options (IPv6/6LoWPAN or Bluetooth Smart gateway) Making Bluetooth Smart smarter: Industry-leading privacy, energy efficiency, and industry-standard security Make Bluetooth Smart faster: improved throughput speed and packet capacity