In this blog post, we’ll explore the principles, features, pros, and cons of Bluetooth, as well as various use cases, to understand the core of short-range wireless communication technology.
Bluetooth is one of the most widely used short-range wireless communication technologies today. Listening to music with wireless earbuds, making hands-free calls in a car, and using wireless keyboards and mice have become part of our daily lives. Would you believe it if you could send a text message to a smartphone sitting right next to you or control a laptop simply by tapping your fingernail? “NailO,” developed by researchers at MIT, was a prime example demonstrating this possibility. Even without such new technologies emerging, various wireless products are easy to find all around us. When making calls in the car, you don’t need to hold your smartphone in your hand—you can talk wirelessly. And among people listening to music with earbuds, it’s rare to see a cable connecting the earbuds to the music player. Furthermore, the Bluetooth logo is a common sight when purchasing these short-range wireless communication products. So, what exactly is Bluetooth, and how is it related to wireless communication?
Bluetooth is a short-range wireless communication technology standard devised in 1994. The name “Bluetooth” is derived from Harald Blåtand (Harold Bluetooth in English), a 10th-century Danish king. This king strove to unify Denmark, which was divided into various factions, and the Bluetooth technology similarly embodies the goal of connecting a wide range of wireless products from different manufacturers under a single standard. Currently, Bluetooth is broadly categorized into Bluetooth Classic (BR/EDR) and Bluetooth LE (Low Energy). Bluetooth Classic is suitable for continuous one-to-one wireless connections between two devices and is widely used in wireless speakers, headsets, and in-car hands-free systems. In contrast, Bluetooth LE is a technology that significantly reduces power consumption and is designed to connect only when necessary or to communicate with multiple devices. Thanks to these characteristics, it is widely used in wearable devices such as smartwatches, fitness trackers, and heart rate sensors, as well as in Internet of Things (IoT) devices.
Although they are different types, Bluetooth systems fundamentally transmit and receive data in the same way. Bluetooth uses the 2.4 GHz ISM (Industrial, Scientific, and Medical) band to transmit data. The ISM band is a frequency band designated for industrial, scientific, and medical use, but since it can be used without a separate frequency license, it is also widely used for low-power short-range wireless communication. However, since this band is shared by various wireless devices such as Wi-Fi, there is a risk of radio interference. To minimize this, Bluetooth uses FHSS (Frequency Hopping Spread Spectrum). In this method, data is transmitted by rapidly switching between multiple channels. Bluetooth Classic communicates by switching between up to 79 channels approximately 1,600 times per second, and it also utilizes Adaptive Frequency Hopping (AFH) technology, which automatically excludes channels with severe interference. Thanks to this method, interference with other wireless devices is reduced, enabling stable communication.
In addition to its low susceptibility to interference, Bluetooth offers several advantages that make it well-suited for short-range communication. First, since it is a wireless communication technology, devices can communicate freely within a certain range without the need for cables, even in the presence of walls or obstacles. Furthermore, because it supports omnidirectional communication, connected devices do not need to maintain a specific angle or arrangement. Due to its nature as a short-range communication technology, the transmission and reception distances are short, so high output power is not required, resulting in lower power consumption. Since signals do not travel far, interference is relatively minimal even when multiple Bluetooth devices are used simultaneously in the same space. Furthermore, as it is a globally standardized technology, it offers high compatibility even across different manufacturers, and the device discovery and pairing processes are simple. For these reasons, Bluetooth is standard in various peripherals used at close range—such as speakers, headsets, keyboards, mice, and game controllers—and is provided as a standard feature in most information devices, including smartphones, tablets, and laptops.
However, Bluetooth does have its drawbacks. Although data transfer speeds are continuously improving, Bluetooth is still at a disadvantage when it comes to transferring large files compared to standard Wi-Fi. Therefore, while it is suitable for listening to music, making voice calls, and connecting peripherals, Wi-Fi is often a better choice for quickly exchanging large amounts of data. Caution is also required from a security perspective. In the past, there were reports of attacks exploiting Bluetooth vulnerabilities, but security levels have improved significantly thanks to ongoing enhancements in authentication and encryption technologies. However, security risks can still arise if devices are left in discoverable mode for extended periods without necessity or if the latest security updates are not applied, so user caution is required.
Bluetooth’s low power consumption and ability to provide stable short-range wireless communication have played a key role in establishing it as a core technology for wearable devices and Internet of Things (IoT) devices. Recently, the scope of its applications has expanded further with the introduction of new technologies such as Bluetooth LE Audio, Auracast, and Bluetooth Mesh networks. Although it competes with other wireless communication technologies such as Wi-Fi Direct and Ultra-Wideband (UWB), Bluetooth is expected to continue to be widely used as a core short-range wireless communication technology in various wireless devices thanks to its low power consumption, excellent compatibility, and continuous performance improvements.
