Many technologies have helped people keep in touch with loved ones as digital communication continues to expand. Among the most widely used options is Bluetooth, a wireless feature now common in several devices used daily.
It allows users to connect items like keyboards and mice to their computers without physical cables. It’s also how mobile phones link up with car audio systems during drives, and how smartwatches and fitness trackers stay connected to phones.
For two electronic devices to successfully exchange information, they must first establish a mutual understanding on specific points. The first agreement deals with how they will interact, through physical wiring or wirelessly.
Where cables are involved, questions arise about how many are needed, whether it is one, two or more. Once the connection type is confirmed, other technical details come into play.
Tiny radio waves make big connections every day (Photo: Twitter)
These include the volume of data that can be exchanged at a time. For instance, serial ports send data one bit at a time while parallel ports can send several bits simultaneously.
Additionally, both devices must speak the same digital language — they must share protocols that define how information is sent and received, including how errors are detected and corrected.
Bluetooth Special Interest Group (SIG) is responsible for setting the standards that guide manufacturers on how Bluetooth should be used. As devices evolve, Bluetooth also keeps improving.
Currently, developers rely on two major versions of Bluetooth to maintain connections. Though the two serve similar functions, each has particular features that make it more suitable for specific uses.
Bluetooth Connections
Wireless communication is now very normal and widely used. Many people have WiFi set up in their homes and offices. But unlike WiFi which connects devices through a router, Bluetooth allows devices to link directly. This simplicity reduces power consumption and helps batteries last longer.
Bluetooth gadgets use low-energy radio waves that operate on frequencies between 2.400 GHz and 2.483.5 GHz. These frequencies fall under the ISM band, which has been reserved internationally for industrial, scientific and medical tools.
Other items such as baby monitors, cordless phones and garage door openers also work using this same frequency range. Because of that, Bluetooth technology needs to work in a way that avoids interfering with other wireless systems.
As of 2020, there are two Bluetooth standards: Bluetooth Classic (also called Bluetooth Basic Rate/Enhanced Data Rate or BR/EDR) and Bluetooth Low Energy (LE).
Both operate on the same frequency, but Bluetooth LE has become the more preferred choice due to its efficient energy usage and its flexibility to support point-to-point, broadcast and mesh network connections.
Bluetooth Classic can send more data in a single go than Bluetooth LE—up to 3 Mbps as against 1 or 2 Mbps. However, its communication is limited to only two devices at a time. Each version has benefits, so manufacturers pick the one that matches their product goals.
Why Is It Called Bluetooth?
Harald Bluetooth, a king who ruled Denmark in the late 900s, is the inspiration behind the name. He successfully united Denmark and a part of Norway under one rule and played a key role in introducing Christianity to the Danes. One of his lasting marks is the Jelling rune stone, a tribute to his parents.
He died in 986 during conflict with his son, Svend Forkbeard. The Bluetooth name acknowledges the major contributions of Nordic countries like Denmark, Norway, Sweden and Finland to digital communication technologies, even though the name does not describe the technical function of Bluetooth.
How Bluetooth Technology Operates
Bluetooth Classic devices need to be paired before any data can be exchanged. This pairing process creates trust between the two devices, allowing them to share data securely using encryption.
Once the devices come within the necessary range, they start communicating electronically to confirm mutual trust and check for data to share. The user is rarely required to press anything for this to happen — the devices handle the process themselves. After trust is established, the devices then form a small wireless group or network.
Bluetooth LE follows a slightly different procedure. Devices may or may not need to be paired. A LE device that is ready to be found starts sending out specific messages known as advertising packets.
These packets give out relevant details about the device. Another compatible device scans the surroundings for these packets and identifies the ones it can work with. Normally, scanning is initiated by the user through an app, like when a smartphone is searching for nearby Bluetooth devices. Once scanning results show available options, the user picks the one they wish to connect to.
Bluetooth accessories such as watches and fitness bands that are connected to a central device like a phone form what is called a piconet or personal area network (PAN). This setup might cover an entire house or just the small distance between a pocketed phone and a smartwatch.
After establishing a piconet, the connected devices automatically jump between radio frequencies together. This helps prevent interference with other Bluetooth or WiFi devices that may also be operating in the same space.
Bluetooth technology is even smart enough to detect which frequencies are clear and which ones have interference so that it can stick to the better options. This method is called adaptive frequency hopping, and it keeps Bluetooth connections stable in places filled with wireless activity.
Bluetooth Range
Although many believe Bluetooth is only useful for close-range connections, it is capable of working over much longer distances — even beyond one kilometre in some cases.
Some devices, like wireless earbuds, are designed to work within a short range for practical and security reasons. But because the Bluetooth system is adjustable, manufacturers can fine-tune their products to balance connection range, battery consumption and signal strength.
Several things determine how far a Bluetooth device can communicate:
Radio frequency band: Bluetooth’s designated frequency range is suitable for stable wireless data exchange.
Physical layer or PHY: This part defines how the Bluetooth signal is structured and how errors and interference are managed.
Receiver sensitivity: This is about how weak a signal can be while still being understood correctly by the receiving device.
Power of transmission: A stronger signal can travel further, but it will also use more battery.
Antenna gain: This describes how signals are converted and received between the transmitter and the receiver.
Path loss: Environmental conditions like moisture, obstacles such as walls or metal, and distance can all weaken the Bluetooth signal.
A more recent feature in Bluetooth called forward error correction (FEC) helps extend signal range without using more power. FEC works by fixing data errors on the receiving end, making it possible for devices to communicate even when far apart and the signal has become weaker.
Bluetooth Security
Bluetooth comes with several layers of protection that meet even strict government security standards like those set by the Federal Information Processing Standards (FIPS).
Your smartwatch chats with your phone quietly in the background (Photo: Getty Images)
When connecting a new device, users go through a pairing process. This step gives both devices private keys that allow them to trust and communicate securely. Without pairing, devices will refuse to connect with each other.
These security features let Bluetooth protect data in various ways. For example, data exchanged can be encrypted to prevent outsiders from reading it. Also, Bluetooth can hide a device’s identity by changing its address every few minutes, helping to shield users from being tracked using their electronic devices.
People who own Bluetooth products may already be familiar with how this works. For example, when you first use a cordless mouse, you pair it to your laptop by turning it on and selecting it from the Bluetooth menu. Computers are designed to manage several Bluetooth connections at once, so using a cordless keyboard, headphones, and a mouse together is no problem.
However, the accessories themselves are usually made to connect with only one device at a time. You would want your wireless keyboard to respond only to your laptop, and your headphones to play sound only from your phone.
Some gadgets may support pairing with several devices but still allow connection to just one at a time. This depends on how the manufacturer designed it. Some connections even require entering a code during setup. This step, called authentication, is meant to confirm that the devices being linked are the correct ones the user intends to pair.
