[Difference analysis] Bluetooth 4.0 vs Bluetooth 4.1 vs Bluetooth 4.2 vs Bluetooth 5.0

A while ago, I saw the latest announcements from major testing organizations to forward Bluetooth certification. The notice shows that with the promulgation and implementation of the new Bluetooth standard, the old standards will be phased out.

In order to encourage members to gradually abandon the old Bluetooth standard of the Bluetooth core specification and switch to the new Bluetooth core specification version of the Bluetooth standard to improve interoperability and quality, the Bluetooth SIG Board of Directors formally approved the Bluetooth core specification version to be deprecated and revoked. plan.

1. The implementation of the deprecated Bluetooth core standard version 2.0/2.0+EDR will be implemented from December 19, 2017;

2. The cancellation of the Bluetooth Core Standard Version 2.0/2.0+EDR will be implemented from July 1, 2018;

3. The implementation of the deprecated Bluetooth Core Standard Edition 4.0/3.0/2.1/2.1+EDR will be implemented from July 1, 2018;

4. The implementation of the cancellation of the Bluetooth Core Standard Edition 4.0/3.0/2.1/2.1+EDR will be implemented on January 1, 2020;

5. Implementation of the deprecated Bluetooth Core Standard Version 4.1 from January 1, 2019;

6. The Bluetooth Core Standard Version 4.1 will be revoked on July 1, 2020.

The certification notice issued by the SIG has not been found on the official website. It must have been considered by the SIG. The announcement has been revoked. The old standard has not been revoked so quickly. So the above information can be read, and the SIG announcement.

https://www.bluetooth.com/specifications/bluetooth-core-specification/deprecated-specifications

The Bluetooth certification notice reminds me of the routine of Andy Beer's Law, What Andy gives, Bill takes away. With the development of semiconductors and powerful processor chips, there are naturally more hardware resources available to run more complex Bluetooth protocols and software. The SIG has issued new standards every year, adding new features and requiring more Hardware resources to run more complex algorithms and protocols, natural old hardware can not be eliminated without the new software.

Bluetooth 4.0 includes both classic Bluetooth and BLE. Today, we focus on the differences between Bluetooth 4.0 and later BLE.

Bluetooth 4.1 vs Bluetooth 4.0

1. Increase data transfer rate

Compared to Bluetooth 4.0, the Bluetooth 4.1 single packet data transfer maximum is increased from 20 bytes to 23 bytes, which increases the data transfer rate by 15%. According to this rule, you can try to modify the value of the single packet data payload. If the chip only supports BT4.0, then modifying the transmission of 23 bytes will either compile the error or drop the packet during the transmission.

2. Master and slave coexistence

The link layer link layer topology has been updated to allow simultaneous master-slave coexistence (time slice rotation) and a master-to-multiple slave connection topology.

3. Support 32-Bit UUID

32-Bit UUID refers to the UUID carried by the broadcast packet, not the 16-bit and 128-bit UUID that we refer to for the attribute list. The full 128-bit UUID can be obtained by broadcasting the 32-Bit UUID mapping so that the effective broadcast data length in the broadcast packet is more.

Bluetooth 4.2 vs Bluetooth 4.1

1.LE connection security

The pairing encryption links of Bluetooth 4.0 and 4.1 from Spec definition are based on AES-CCM encryption, but since Bluetooth 4.1 shares the same key, there are risks and vulnerabilities that are cracked. The pairing link of Bluetooth 4.2 is encrypted by the Diffie-Hellman Key Exchange key exchange algorithm. Each device has a pair of key pairs, a public key and a private key. The private key is saved by itself, and the public key is disclosed to the other party. When the data is exchanged, one party The encrypted file is encrypted by the private key of the user and the public key of the other party, and the receiver decrypts the private key of the transmitting party and the public key of the transmitting party, thereby effectively preventing the middleman from cracking the key event.

2. Privacy protection

Bluetooth broadcasts its own BD address (bluetooth device address), which is the unique MAC address of Bluetooth. It is very helpful in some applications, such as logistics tracking applications. It can fix logistics equipment according to BD address.

However, in some applications, it is not expected that the BD address is exposed to the monitoring of the master device. Bluetooth 4.2 gives a flexible choice. According to Bluetooth 4.2, the slave device can choose to send a random BD address in the broadcast mode, so that the master The device can obtain its real BD address after receiving the device, except that the BD address of the device broadcast mode is a random sequence.

3. Big data transmission

Bluetooth 4.1 supports up to 23 bytes of single packet data transmission, and Bluetooth 4.2 supports up to 255 bytes of single packet data transmission, which greatly improves the data transmission rate.

Bluetooth 5.0 vs Bluetooth 4.2

1.Long distance

Thanks to forward error coding and mode mapping, the RX end has different improvement in decoding and error correction capability of the entire payload data packet during the transmission process (simply speaking, to improve the receiving sensitivity of the RX terminal), and the transmission distance of the Bluetooth 5 Only a significant improvement

2. Long broadcast package

The Bluetooth 4.x protocol stipulates that Bluetooth broadcast data packets only support a maximum of 31 bytes of data transmission per packet, and the broadcast channel is limited to three channels of 37, 38, and 39. Based on the original PDUs for transmitting broadcast data (ADV_IND, ADV_DIRECT_IND, ADV_NONCONN_IND, and ADV_SCAN_IND, called legacy PDUs), Bluetooth 5 adds extended PDUs (ADV_EXT_IND, AUX_ADV_IND, AUX_SYNC_IND, and AUX_CHAIN_IND, called extended advertising PDUs). At the same time, it also allows Bluetooth to send data with a length of 0-255 bytes on 37 channels other than the three channels of 37, 38, 39.

3. Big data transmission

Compared with Bluetooth 4.2, Bluetooth 5 supports two PHYs, 1M PHY and 2MPHY. The data transmission rate of 2M PHY is a new feature of Bluetooth 5.0. Before Bluetooth 4.2, only the rate of 1Mbps PHY is supported. Like Bluetooth 4.2, Bluetooth 5 also supports a single packet of 255 bytes of data transmission, so the speed of Bluetooth is doubled compared to 4.2.

Summary:

At present, there are still a large number of Bluetooth 4.0/3.0/2.1/2.1+EDR products on the market, ranging from self-timer and remote control to various smart devices. Because of their ability to use, the price is low, and they are relatives of customers of fast-moving products. Industrial, automotive applications, BT4.0 products are still in the right way, the reasons, stable, enough, good supply, of course, the price is not expensive. But if Bluetooth 5 solves the problem of Bluetooth connection between a single-point connected wearable device and a mobile phone before Bluetooth 5, then Bluetooth 5 is the problem of solving the multi-point interconnection IoT (Internet of Things).