2.4 GHz vs 5 GHz WiFi: Understanding the Differences

The term Wi-Fi is short for Wireless Fidelity. It’s a wireless technology that allows devices to connect to the internet and local networks without physical cables.

Wi-Fi uses radio waves to transmit data between devices and a wireless router or access point. The Wi-Fi router acts as a central hub, providing the connection to the internet and allowing multiple devices to connect simultaneously. Each connected device communicates with the router over a specific radio frequency, commonly in the 2.4 GHz, 5 GHz, or 6 GHz frequency bands, depending on the Wi-Fi standard and the device’s capabilities.

Let’s compare 2.4 GHz WiFi vs 5 GHz WiFi, examining the differences in speed, range, wavelength, advantages, disadvantages, and other parameters.

Introduction

WLAN (Wireless LAN) was developed to overcome the cabling difficulties found in cabled LANs. WLAN is wireless and uses the ISM band with three frequency ranges: 902-928 MHz, 2400-2483.5 MHz, and 5725 to 5850 MHz.

Wireless Local Area Networks follow the IEEE 802.11 series of standards. It works similarly to a traditional LAN, except it has a wireless interface. WLAN allows users to move around within a selected area while still connected to the internet.

Several WLAN versions define the PHY (Physical) Layer and MAC (Medium Access Control) layer with distinct features such as QoS, Security, and data rates. Initially, WLAN hardware was expensive and used only in scenarios where cabling was very difficult or impossible in a wired LAN network. Nowadays, WLAN components are cheaper and widely used in homes, enterprises, and commercial public areas. The transmission technologies used in WLAN are spread spectrum and infrared.

In spread spectrum (SS) transmission, two modulation schemes are employed: FHSS (Frequency Hopping SS) and DSSS (Direct Sequence SS).

Infrared transmission uses infrared light to carry information and has three types: diffused, directed, and directed point-to-point.

Figure-1 : WLAN Architecture

WLAN networks can be implemented in two ways: ad-hoc mode and infrastructure mode.

Ad-hoc mode is used by a small number of mobile users and doesn’t require an AP or router. Infrastructure mode is set up by APs (Access Points) or routers. Here, a group of stations belonging to an AP is called a Basic Service Set (BSS). Multiple BSSs are connected to each other and to a DS (Distributed System) by APs (Access Points). This is shown in the WLAN architecture above.

An AP (Access Point) provides interoperability between wired computing devices and Wi-Fi devices. It’s also known as a Wi-Fi router. It’s usually connected to a single broadband internet connection so that multiple Wi-Fi devices can share a single broadband connection for high-speed browsing. Both 2.4 GHz and 5 GHz frequencies are used in various Wi-Fi standards.

The following table mentions the series of 802.11 standards developed by the IEEE WLAN group.

Let’s understand the 2.4G and 5G radio frequencies used in these Wi-Fi versions.

The figure depicts the frequency spectrum of both 2.4GHz and 5GHz frequencies. As shown, 2.4g will have fewer cycles in the same time period as 5g. In the Electromagnetic spectrum, 5g is considered a higher frequency than 2.4g.

Figure-2 : 2.4 vs 5 GHz waveforms

2. 4 GHz frequency corresponds to 0.125 meters of wavelength, whereas 5 GHz frequency corresponds to 0.060 meters. Due to the larger wavelength, a 2.4 GHz signal can easily pass through walls and solid objects. Hence, it covers larger distances and provides better coverage. Therefore, 2.4 GHz can be used in large hotels requiring coverage for guests in many rooms and outdoors. It’s also used in pubs/restaurants with multiple walls.

About 2.4 GHz WiFi

Figure-3 : 2.4 GHz wifi channels

The figure depicts 2.4 GHz channels used in Wi-Fi networks by routers or APs (Access Points) and Stations (STAs) or clients. Among all the channels, channel-1, channel-6, and channel-11 are non-overlapping channels as they are separated by a spacing of 25MHz. The rest of these three channels are known as overlapping channels as they share some frequency spectrum space.

Here are some silent features of 2.4 GHz WiFi:

• Better coverage range
• Universally compatible
• Used in the 802.11b standard
• Lower bandwidth than the 5 GHz version
• Higher interference due to the use of 2.4 GHz by many devices. Moreover, there are only three non-overlapping channels (i.e., 1, 6, and 11).

The power spectrum mask of 2.4 GHz frequency channels is shown below.

Figure-4 : 2.4 GHz power spectrum mask

About 5 GHz WiFi

Figure-5 : 5 GHz wifi channels

The figure depicts 5 GHz channels used in Wi-Fi networks. As shown, there are 25 pre-defined channels starting from 36, 40, 44, 48, and going till 149, 153, 157, 161, and 165. UNII-1 Channels are used for domestic applications and are the best to use among 5GHz wifi channels. These channels are used for various bandwidths (20 MHz, 40 MHz, 80 MHz, 160 MHz) in different WLAN standards.

Here are some silent features of 5 GHz WiFi:

• Faster network speed
• Less interference than 2.4 GHz
• More bandwidth options available
• Shorter range than the 2.4 GHz version

IEEE has not defined channel width for 5 GHz channels.

The power spectrum mask of 20 MHz OFDM frequency channels is shown below.

Figure-6 : OFDM spectrum mask

Tabular difference between 2.4 and 5 GHz WiFi

The following table compares 2.4 GHz vs 5 GHz WiFi with respect to different parameters such as speed, coverage range or distance, and mentions the difference between 2.4 and 5 GHz Wi-Fi versions.