What is Wi-Fi? Basic Wi-Fi knowledge | NEXTY Electronics, an electronic components and semiconductor trading company

Basic knowledge of Wi-Fi

In this column, we will explain the basics of Wi-Fi, which is already used by many people.
This time, as basic knowledge of Wi-Fi,
・Basic overview of Wi-Fi: "What is Wi-Fi?", "History and evolution of Wi-Fi"
・Wi-Fi technical basics: "Fundamentals of wireless communication," "Frequency bands and channel width"
Focus on.

Wi-Fi basics overview

What is Wi-Fi?

Wi-Fi is a type of radio/wireless communication technology, also known as WLAN (Wireless Local Area Network).
Wi-Fi is a technology that uses radio waves (electromagnetic waves) to send and receive data between devices, allowing you to Access the Internet without a wired connection. Wi-Fi is used by a variety of devices, including computers, smartphones, TABLETS, and smart home devices, and is an essential part of everyday life and business.
To use Wi-Fi, you typically need a device called a router or Access point. These devices receive your internet connection from your Internet Service Provider (ISP) and transmit it as a radio signal to nearby devices. Wi-Fi range depends on the device's capabilities and your environment, but it can generally cover an entire home or office.

Usage example:

PC
Smartphone
TABLETS
Smart Home Devices

Supplementary information/Radio waves (electromagnetic waves):
Radio waves are a type of electromagnetic wave that lies in the lowest frequency band of the electromagnetic spectrum. Radio waves typically fall in the frequency range from a few Hz to a few GHz and are widely used for wireless communication.
Radio waves are used for the following purposes:

Wi-Fi/Wireless LAN
radio broadcasting
Television broadcast
Mobile phone communications
satellite communications
radar

History and Evolution of Wi-Fi

The history of Wi-Fi dates back to 1985.
It all began in 1985 when the US Federal Communications Commission (FCC) opened up the Industrial, Scientific, and Medical (ISM) bands to commercial use, accelerating the development of wireless communication technology and laying the foundation for Wi-Fi.
The first Wi-Fi standard, IEEE802.11, was established by the Institute of Electrical and Electronics Engineers (IEEE) in 1997. This standard provided data transfer speeds of up to 2Mbps and established the basis for wireless networking.
The Wi-Fi Alliance was then founded in 1999 to promote the widespread adoption and compatibility of Wi-Fi technology.

Key Wi-Fi evolutions:

Year	Wi-Fi Alliance	IEEE	Evolution content
1997年	ー	802.11	It uses the 2.4GHz band and offers speeds of up to 2 Mbps.
1999年	ー	802.11b	It uses the 2.4GHz band and offers speeds of up to 11 Mbps. It is becoming popular in homes and small offices.
1999年	ー	802.11a	It uses the 5 GHz band and offers speeds up to 54 Mbps, allowing for faster speeds with less interference.
2003年	ー	802.11g	It uses the 2.4 GHz band, provides speeds up to 54 Mbps, and is backward compatible with 802.11b.
2009年	Wi-Fi 4	802.11n	It provides speeds of up to 600 Mbps and incorporates MIMO (Multiple Input Multiple Output) technology.
2014年	Wi-Fi 5	802.11ac	Provides speeds of up to 1 Gbps or more. Achieves high-speed communication in the 5 GHz band.
2021年	Wi-Fi 6/6E	802.11ax	Offers speeds up to 9.6 Gbps, enhancing efficient bandwidth utilization and simultaneous multi-user connections.
2024 (Plan)	Wi-Fi 7	802.11be	Provides speeds of up to 46 Gbps. Implements MLO (Multi Link Operation) technology to improve latency.

Wi-Fi technology continues to evolve to provide faster and more reliable connections, and is now used in a wide variety of applications, including IoT devices, smart homes, and streaming services.

Technical Basics of Wi-Fi

Wireless Communication Fundamentals

Wireless communication is a technology that uses electromagnetic waves (radio waves) to send and receive information. Wireless communication technology transmits wireless signals through space, providing a means of communication that does not require wired CABLES.
The foundation of wireless communication consists of the following key components and concepts:

Component Concept:

component	Component Concept
Electromagnetic waves (radio waves)	Wireless communication uses electromagnetic waves. Electromagnetic waves are formed by fluctuations in electric and magnetic fields and propagate at the speed of light. The electromagnetic waves used in wireless communication are limited to low frequency bands ranging from a few Hz to a few GHz, from radio waves to microwaves, and are called radio waves.
frequency	Frequency is the number of times an electromagnetic wave oscillates per second and is measured in Hertz (Hz). Wireless communications use specific frequency bands, which allow different communication systems to coexist without interfering with each other.
Transmission and Modulation	On the transmitter side, modulation is performed, which is the process of imposing the information to be transmitted onto electromagnetic waves (radio waves). Common modulation methods include amplitude modulation (AM), frequency modulation (FM), and phase modulation (PM). Wi-Fi primarily uses OFDM (Orthogonal Frequency-Division Multiplexing).
Reception and demodulation	At the receiver side, ANTENNAS receives the electromagnetic waves and demodulates the modulated signal to restore the original information, which involves the receiver analyzing the signal and removing noise.

Wireless communication configuration diagram

Frequency bands and channel widths

Wi-Fi wireless communication uses a specific frequency band, which allows multiple devices to communicate simultaneously. Below we will explain the main frequency bands and channel widths used by Wi-Fi.

Frequency band characteristics:

Frequency band	Features
2.4GHz帯	Frequency range: 2.4 GHz (2.400 GHz to 2.4835 GHz) Wide coverage: The low frequency allows the signal to penetrate obstacles more easily, providing coverage over a wider area. Interference: Many household devices (e.g. microwave ovens, Bluetooth devices) and other Wi-Fi networks also use this band, so there may be a lot of interference. Data speed: The maximum speed is 600 Mbps for Wi-Fi 4 (IEEE 802.11n) and 54 Mbps for IEEE 802.11g, which is slower than the 5 GHz and 6 GHz bands. ・Standards used: IEEE 802.11b/g/n supported.
5GHz帯	Frequency range: 5 GHz (5.150 GHz to 5.825 GHz) Speed and performance: Higher frequency bands enable faster data transfer rates and wider bandwidths, enabling higher throughput. This is especially evident in Wi-Fi 5 (IEEE 802.11ac) and Wi-Fi 6 (IEEE 802.11ax). Interference: Fewer devices are using the 2.4 GHz band, resulting in less interference and a more stable connection. - Coverage: Because of the high frequency, it has difficulty passing through obstacles and walls, which may result in a limited coverage range. ・Standards used: IEEE 802.11a/n/ac/ax/be supported.
6GHz帯	Frequency range: 6 GHz (5.925 GHz to 7.125 GHz) - Latest technology: Supports Wi-Fi 6E (IEEE 802.11ax)/Wi-Fi 7 (IEEE 802.11be), the latest frequency band, providing additional bandwidth and low latency. - Low interference: Currently, there is little use of other wireless devices, so there is very little interference, providing a very clean signal environment. Speed and capacity: High data transfer speeds and low latency provide exceptional performance. Coverage: As with the 5 GHz band, the coverage range is narrower due to the high frequency, and signal attenuation by obstacles is significant. ・Standards used: IEEE 802.11ax/be supported.

Channel width characteristics:

Channel Width	Features
20MHz	-Data speed: Low. - Low interference: The narrow width means less interference and a stable connection. - Coverage: Narrow signal spread and high resistance to obstacles. ・Usage: Compatible with a wide range of Wi-Fi standards. ・Supported standards: IEEE 802.11a/g/n/ac/ax/be (IEEE 802.11b: 22MHz)
40MHz	-Data speed: Medium. Potential for interference: Using twice the width of a 20 MHz channel increases the risk of interference. Coverage: Possibly less coverage than 20 MHz, but offers better speeds. ・Supported standards: IEEE 802.11n/ac/ax/be are supported.
80MHz	・Data speed: High speed. Risk of interference: Because it uses a wider bandwidth, there is a greater risk of interference, but it also offers significantly faster speeds. -Coverage: Because the channel width is wide, coverage tends to be narrow. ・Supported standards: IEEE 802.11ac/ax/be supported.
160MHz	-Data speed: Very fast. Risk of interference: The wide range means there is a very high chance of interference, but the data transfer speeds are significantly faster. Coverage: Coverage tends to be narrow. ・Supported standards: IEEE 802.11ac/ax/be supported.
320MHz	・Data speed: Super fast. Risk of interference: Because it uses such a wide bandwidth, it is highly sensitive to the environment in which it is used, as it poses the greatest risk of interference. Coverage: This offers the lowest coverage but extremely high data rates. ・Supported standards: IEEE 802.11be supported.

Wi-Fi wireless communication channel width diagram

Summary

This time, we provided basic knowledge and an overview of Wi-Fi, focusing on "What is Wi-Fi?" and "The history and evolution of Wi-Fi," as well as the technical foundations of Wi-Fi, focusing on "The basics of wireless communication" and "Frequency bands and channel width."
In the next article, we will discuss the technical structure of Wi-Fi in detail, and explain the main technical elements of Wi-Fi and its technical features.