Bluetooth WiFi and Infrared technology

In this article, we’re going to look at the tools of smartphone connectivity (Bluetooth WiFi and Infrared).

Smartphones are devices designed for communication and connectivity. Thus their primary function is communication. Smartphones come with a range of tools that help them carry out this function.

Communication and connectivity entail being able to access mobile broadband, as well as the Internet. It also means connecting to other electronic devices such as smartphones, Bluetooth headsets, smartwatches, smart TVs etc.


The main connections used by phones include Internet/mobile broadband, USB, Bluetooth WiFi, and Infrared technology.

Bluetooth WiFi and Infrared technology

As you may have noticed, all of the following except one are wireless. The shift from using wired communications to wireless started as far back as the 1980s. Modern smartphones today are almost all wireless except for their charging ports (the high-end phones have wireless charging). These were all made possible by the addition of radios and modems to the smartphone. Sometimes, these radios are embedded into the SoC. Other times they are attached to the motherboard outside of the SoC.


Bluetooth is a wireless standard used for exchanging data between devices. This could be between fixed (e.g. Personal Computers) and/or mobile devices (e.g. smartphones) over short distances. It was introduced in 1989. Bluetooth was first used in phones in 2001 appearing in the Ericsson T36.
It quickly became popular and replaced the older and slower Infrared means of inter-device communication.

Bluetooth WiFi and Infrared technology
The Ericsson T39 (credits: Wikipedia)


1. File sharing: Its major use was for file transfer e.g. documents, multimedia, etc. It is only used to transfer small files these days. This is because file sizes have gotten larger and it is impracticable to send them via Bluetooth.

2. Interconnectivity between devices: this is now the primary use of Bluetooth technology especially in this age of IoT (Internet of Things). The inter-device connection includes a headset to a smartphone, a smartphone to a smartwatch, and a printer to a PC. It also includes smartphones to PCs or printers, video game consoles to controllers (gamepads), etc.


1st generation

The first generation Bluetooth radios, Bluetooth version 1.0 was released in 1999. It had a speed of 1 Mbps (megabit per second) which is equivalent to 0.125 megabytes per second. Its range was very short (10 meters) and it consumed a lot of battery. It could also only connect to one device at a time. Bluetooth 1.0B (2001), Bluetooth 1.1 (2001), and Bluetooth 1.2 (2003) only came with very minor improvements.

Bluetooth WiFi and Infrared technology
Bluetooth logo (credits: Wikipedia)

2nd generation

The second generation Bluetooth 2.0+ EDR (Enhanced Data Range) was released in 2004. It was an improvement on the first generation. It could transfer data at 2 to 3 Mbps (0.25 to 0.375 MB/s) but it didn’t improve on the range or battery consumption. A slight upgrade known as Bluetooth 2.1+ EDR was released in 2007.

3rd generation

The third generation promised much and delivered on its promise. Well, at the expense of huge battery consumption. The version 3.0+ HS (High Speed) is still used by many headphones today because it transfers data at speeds of up to 24Mbps (3 MB/s) and consumes a lot of battery as well.

4th generation

The fourth generation took a different approach. It was aimed at low-energy devices like fitness trackers, smartwatches, mice and keyboards, true wireless (TWS) earbuds, etc. The version 4.0 LE (Low Energy) was released in 2010. Version 4.0 transfers data at 1Mbps. Further revisions included the 4.1 (2013) and 4.2 (2014).

5th generation

The current generation is the 5th Bluetooth generation (i.e. Bluetooth 5.0). It improves on 4.0 by increasing data transmission speeds but maintaining low power consumption. Bluetooth 5.0 has data transmission speeds of 2 Mbps and a range of 240 meters which when compared to the old 10-meter range is massive.

In addition, Bluetooth 5.0 consumes less battery and has lower latencies when compared to its predecessors.

The Current iterations include Bluetooth 5.15.2, and 5.3.


This is a family of wireless network protocols based on the IEE802.11 family of standards for Local Area Networks (LAN) and Internet Alliance. It is the wireless equivalent of Ethernet (a wired internet connection). Wi-Fi uses a radio antenna and bands (just like Bluetooth) to transmit data (files or internet).

Wi-Fi can send data over very large areas. It works best if there is no obstruction between the access point (or hotspot) and the receiver. A smartphone’s Wi-Fi hotspot has a range of 20 to 150 meters. Like any wireless network, it is less secure than wired connections. This is why most people are advised against using insecure Wi-Fi connections in public places. This is to prevent them from being hacked and their data stolen.

Bluetooth WiFi and Infrared technology


Inter-device connectivity: Wi-Fi is used to connect two devices wirelessly.

File Sharing: A lot of apps have been developed to take advantage of this. The most popular of these is Xender which took over from a one-time favorite, Flash Share. Wi-Fi can be used to send large amounts of data within a fairly short time.

Internet Sharing: Wi-Fi can also be used to share internet connectivity between two devices with one acting as a hotspot (host) and the other acting as a receiver. Examples include phone-to-phone internet data sharing via hotspot as well as a Wi-Fi router to a Smartphone or PC.

Screencasting: Newer smart TVs come equipped with Wi-Fi. The regular TVs that do not come with Wi-Fi can be fitted with a Wi-Fi receiver to which audiovisual data from your smartphone or laptop can be streamed to your TV set.

City-wide Internet: Many cities in first-world countries have city-wide Internet where the Internet is transmitted to the populace by the means of powerful routers strategically placed all over the city. These could be free, subsidized, or paid for.

Geolocation: The position of a phone can be pinpointed by locating the nearest Wi-Fi to which a phone is connected.


Infrared ( or IR for short) wireless is the use of wireless technology to send/transfer data. It is used for short and medium-range connections.

Infrared rays are generated by the phone as pulses of light which are focused through a piece of semi-transparent plastic called an IR blaster. This piece of plastic is then aimed at the receiving device which accepts the information. The IR blaster is usually found at the top of the phone.

Showing the location of an IR blaster on a smartphone
An IR blaster on the Redmi Note 9 Pro


IR technology is very old and was once used on phones as the primary method of file sharing but it was painfully slow and was soon replaced by Bluetooth in the early 2000’s. it is used these days to turn smartphones into universal remotes for household and/or car appliances.

Bluetooth WiFi and Infrared are now indispensable to smartphone connectivity. We simply can’t do without them.

This brings us to the very end of this post, thank you for reading to the end.

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