Bluetooth is a wireless technology standard that enables short-distance data exchange between fixed devices, mobile devices and building personal domain networks, Which using UHF radio waves in the ISM band of 2.4~ 2.485ghz (Bluetooth, 2020).

Bluetooth originally invented by telcome giant Ericsson in 1994, which was used as an alternative to the RS232 data line

Now, Bluetooth is managed by Bluetooth Special Interest Group (SIG). The Bluetooth Special Interest Group has more than 35,000 member companies in telecommunications, computing, networking, and consumer electronics. The IEEE standardized Bluetooth as IEEE 802.15.1, but no longer maintains the standard (Bluetooth, 2020).

With the update of technology, Bluetooth version has developed from 1.0 to 5.0. All versions of the Bluetooth standards support downward compatibility.That lets the latest standard cover all older versions.

Bluetooth version 5.0 was released by Bluetooth SIG on 6 December 2016. The new features are mainly focused on new Internet of Things technology

Bluetooth 5.0 is aimed at low-energy devices, has a wider coverage and a four-fold increase in speed. Moreover, it will add an auxiliary function for indoor positioning, and combined with Wi-Fi, indoor positioning with an accuracy of less than 1 meter can be achieved.

The upper limit of the low-power mode transmission speed is 2Mbps, which is twice that of the previous 4.2LE version. And the effective working distance can reach 300 meters, which is 4 times that of the previous 4.2LE version.

The major areas of improvement are: Slot Availability Mask (SAM), 2 Mbit/s PHY for LE, LE Long Range, High Duty Cycle Non-Connectable Advertising, LE Advertising Extensions, LE Channel, Selection Algorithm #2, Features Added in CSA5 (Bluetooth, 2020).