# 25 Years of Bluetooth Technology
## 1 Introduction  
The Bluetooth radio technology was developed by [PERSON] in 1994. The standard is named after the King of Denmark, [PERSON] (\"Bluetooth\"). Major mobile phone manufacturers and technology providers comprising IBM, Nokia, Intel, Ericsson, and Toshiba created the Bluetooth Special Interest Group (SIG). The aim of the group was to invent an open specification for wireless technologies of short range. Bluetooth SIG continues to oversee the Bluetooth technology today. 3 COM, Microsoft, Lucent, and Motorola also promote the SIG group currently. The SIG [1] now has more than 1900 companies since it was created. Classic Bluetooth (which was the original specification of Bluetooth) was intended to transmit data wirelessly between computer devices. Over the last twenty years of SIG existence, Bluetooth technology has constantly been able to meet the growing demands for wireless innovation. Since its introduction in 1998, Bluetooth device shipments continue to increase without the slightest expectation of a decrease in demand. Figure 1 shows the previous and predicted annual Bluetooth device shipments [2]. Main contributions of this work We summarize the main contributions of this work as follows:  
* We present the evolution of Bluetooth technology over the last two decades as well as current and future trends of Bluetooth. * We describe internetworking solutions between Bluetooth and IP-based networks. We also present the communication protocols used between Bluetooth and Zigbee. * We discuss recent attacks on Bluetooth and solutions to mitigate them. * Finally, we highlight state-of-the-art research efforts that have been leveraging Bluetooth technology to provide innovative solutions in areas such as health, location tracking, and smart homes. Bluetooth Low Energy, generally referred to as \"Bluetooth Smart\" was specifically created for scenarios, which have a low duty cycle and was marketed to the public in October 2010. For instance, a belt that records the heart rate can be hooked on for many hours, say during a workout session, but will only need to send limited number of bytes of data per second. Therefore, in an enhanced and optimized protocol, Bluetooth radios will be kept \"on\" for just a few milliseconds. In comparison, a headset or a wireless speaker would transmit much more data (typically many kilobytes in just one second and the radio is turned on for a reasonably longer time. Bluetooth Low Energy (BLE) was devised specifically for use cases that Bluetooth classic was not suited for. Currently, Bluetooth Smart has been broadly adopted in many types of health and fitness applications including some sports-related use cases. The BLE technology also has potential for use in medical devices and for newer applications such as beacons and proximity tags. Recently there is also an increase in many types of \"connected\" devices for home networking and smart grids, as well as an array of smart watches, motion monitoring devices and other smart tools and gadgets. Bluetooth Smart serves as a driver of the Internet of Things (IoT). Instead of acquiring a direct Internet connection, gadgets that are Bluetooth Smart may acquire Internet connectivity via other devices that are Bluetooth Smart Ready. This approach provides a cheaper and lower power consuming solution [3]. It is predicted that by 2023, more than 1.6 billion Bluetooth Low Energy devices will be shipped each year, and 90% of all Bluetooth devices will include Bluetooth Low Energy technology [2]. Figure 2 shows the Bluetooth device shipment numbers by the radio version. Figure 1: Annual Bluetooth device shipments (in billions) [2]. Today, we have three main versions of Bluetooth technology, namely: a) Bluetooth Basic Rate (BR)/Enhanced Data Rate (EDR), b) Bluetooth Low Energy (BLE), and c) Bluetooth Mesh. Figure 3 shows the timeline for Bluetooth evolution. The characteristics relevant to each Bluetooth version are shown in Table 1 below. The rest of this paper is organized as follows.