Difference between 2.4 GHz WiFi and 5 GHz WiFi | 2.4 GHz vs 5 GHz

The term Wi-Fi is the short form of Wireless Fidelity. It is a wireless technology that allows devices to connect to the internet and local network without physical cables. Wi-Fi operates using radio waves to transmit data between devices and a wireless router or access point. The wifi router acts as a central hub that provides the connection to the internet and allows multiple devices to connect to it simultaneously. Each connected device communicates with the router over a specific radio frequency, commonly in the 2.4 GHz or 5 GHz or 6 GHz frequency bands, depending on the WiFi standard and the capabilities of the device. Let us compare 2.4 GHz WiFi vs 5 GHz WiFi and derives difference between 2.4 and 5 GHz WiFi versions against various parameters such as speed, range, wavelength, advantages, disadvantages and other parameters.

Introduction: WLAN (Wireless LAN) has been developed to overcome cabling difficulties observed in cabled LAN. WLAN is wireless in nature and uses ISM band with three frequency ranges viz. 902-928, 2400-2483.5 and 5725 to 5850 MHz. Wireless Local Area Networks follow IEEE 802.11 series of standards. It works similar to traditional LAN except it has wireless interface.

WLAN allows users to move around in selected area while they are still connected to the internet. Several WLAN versions define PHY (Physical) Layer and MAC (Medium Access Control) layer with distinct features such as QoS, Security, data rates etc.

Initially WLAN hardware was expensive and they were used only in certain scenarios where cabling was very difficult or impossible in wired LAN network. Now-a-days WLAN components are cheaper and hence it is widely used in home, enterprise 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 viz. FHSS (Frequency Hopping SS) and DSSS (Direct Sequence SS). Refer DSSS vs FHSS for difference between FHSS and DSSS. Infrared transmission uses infrared light to carry information and it has three types viz. diffused, directed and directed point-to-point.

Figure-1 : WLAN Architecture

WLAN network can be implemeted in two ways i.e. adhoc mode and infrastructure mode. Adhoc mode is used by small number of mobile users and it does not require AP or router. Infrastructure mode is setup by APs (Access Points) or routers. Here group of stations belonging to an AP is called Basic Service Set (BSS). Multiple BSSs are connected to each other and to DS (Distributed System) by APs (Access Points). This is shown in the WLAN architecture above.

AP (Access Point) provides interoperability between wired computing devices and wifi devices. It is also known as wifi router. It is usually connected with single broadband internet connection so that multiple wifi devices can share single broadband connection eo experience very high speed browsing.

Both 2.4 GHz and 5 GHz frequencies are used in various wifi standards. Following table mentions series of 802.11 standards developed by IEEE WLAN group.

802.11 Standard	Features
802.11b	• Designated as WiFi 1 • Uses 2.4 GHz frequency band and DSSS/CCK modulation. • The data rate supported are 1, 2, 5.5 and 11 Mbps • Supports coverage distances of 38 meters (indoor) and 140 meters (outdoor).
802.11a	• Designated as WiFi 2 • It is the first standard to use OFDM as multi carrier modulation. • The routers and stations use 5 GHz frequency for communication. • It uses bandwidth of 20 MHz to support different data rates e.g. 6, 9, 12, 18, 24, 36, 48, 54 Mbps. • Supports coverage distances of 35 meters (indoors) and 120 meters (outdoors).
802.11g	• Designated as WiFi 3 • It uses both 2.4 GHz and 5 GHz frequencies. • It supports features of both 802.11a and 802.11b standards.
802.11n	• Designated as WiFi 4 • It supports bandwidths of 20 MHz and 40 MHz. • With features such as MIMO, 40 MHz bandwidth and higher level modulation schemes (64 QAM) data rate of 150 Mbps can be achieved. • Supports coverage distances of 70 meters (indoors) and 250 meters (outdoors).
802.11ac	• Designated as WiFi 5 • It uses 5 GHz carrier frequency. • It supports maximum data rates up to 6.93 Gbps due to higher bandwidth (up to 160 MHz), higher level modulation (such as 256 QAM) and multi-user MIMO. • Coverage distances of 80 meters with 3 antenna can be supported.
802.11ax	• Designated as WiFi 6 • It uses 2.4 GHz and 5 GHz carrier frequencies. • It offers higher speed and coverage distances compare to all the legacy wifi standards. • It supports features such as MU-MIMO, 1024QAM, spatial streams upto 8, long symbol size, BSS coloring and so on. Refer advantages of wifi 6 standard >>.

Let us understand 2.4G and 5G radio frequencies used in these wifi versions. The figure depicts frequency spectrum of both 2.4GHz and 5GHz frequencies. As shown, 2.4g will have less number of cycles in the same time period as 5g. In Electromagnetic spectrum, 5g is considered higher frequency than 2.4g.

Figure-2 : 2.4 vs 5 GHz waveforms

2.4 GHz frequency corresponds to 0.125 meters of wavelength where as 5 GHz frequency corresponds to 0.060 meters. Due to larger wavelength, 2.4 GHz signal cam easily pass through walls and solid objects. Hence it covers larger distances and provides better coverage. Hence 2.4 GHz can be used in large hotels which require coverage for guests in many rooms and outdoors. It is also used in pubs/restaurants which have multiple walls.

About 2.4 GHz WiFi

Figure-3 : 2.4 GHz wifi channels

The figure depicts 2.4 GHz channels used in wifi network 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 spacing of 25MHz. Rest of these three channels are known as overlapping channels as they share some frequency spectrum space. Following are some of the silent features of 2.4 GHz WiFi.
• Better coverage range
• Universally compatible
• Used in 802.11b standard
• Lower bandwidth than 5 GHz version
• Higher interference due to 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 wifi network. As shown 25 pre-defined channels starting from 36, 40, 44, 48 and goes till 149, 153, 157, 161 and 165. UNII-1 Channels are used for domestic applications and are 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. Following are some of the silent features of 5 GHz WiFi.
• Faster network speed
• Less interference than 2.4 GHz
• More bandwidth options available
• Shorter range than 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

Following table compares 2.4 GHz vs 5 GHz WiFi with respect to different parameters such as speed, coverage range or distance, and mentions difference between 2.4 and 5 GHz wifi versions.

Features	2.4 GHz WiFi	5 GHz WiFi
IEEE Standard	802.11 b/g/n/ax	802.11 a/n/ac/ax
Waveform time period	Higher	Lower
Wavelength	0.125 meters, Greater than 5 GHz	0.060 meters, Less than 2.4 GHz
Coverage distance or range	Supports long distances, about 150 feet (~36 meters) indoors and 300 feet (~92 meters) outdoors	Supports short distances, about 50 feet (~12 meters) indoors and 100 feet ( 30.6 meters) outdoors
Speed	Slower, About 450 Mbps to 600 Mbps	Faster, About 1.3 Gbps
Number of channels	11 overlapping channels, 3 non-overlapping channels	25
Bandwidth	Lower	Higher
Cost	Less expensive	More expensive
Non wifi interference	Yes	No
Advantages (i.e. Pros)	Longer coverage, easily pass through walls, floors as well as solid objects	Faster speed, much higher bandwidth, more channels, usually less congested
Disadvantages (i.e. Cons)	Slower speed, lower bandwidth, liable to congestion during peak usage hours	Shorter coverage and more expensive routers and end devices
Applications	Large hotels, pubs, restaurants having more guests and multiple walls between rooms	Hotels and cafes with professionals housing meeting rooms and business conferences.

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