In the day and age of internet and wireless communication, you must have come across the term wireless signal numerous times. Technical experts across social media platforms mention frequency and bandwidths during their reviews. It must be baffling to come across these terms, especially for non-technical individuals.

What are wireless signals?

Wireless signals allow transferring various types of data. Typically, they are electromagnetic waves that travel through the air on specific frequency spectrums. These frequencies are the rates at which the signal can vibrate. Thus, these numbers that bemuse you are nothing but the frequencies at which the routers exchange information, i.e., 2.4GHz or 5GHz.

Let’s delve further and explore some of the essential information about this topic.

Wi-Fi 2.4 GHz vs. 5 GHz

 These numbers refer to two distinct frequencies or bands as used synonymously. The frequencies are commonly used by Wi-Fi routers to transmit the connection. The primary difference between the frequencies is in the form of speed and the range that they offer.

Ideally, wireless transmission with 2.4 GHz wavelength can provide internet to a larger area at the cost of faster speed, whereas at 5 GHz offers a faster speed within a restricted location. You need to note that every router consists of a different set of frequencies. To gain the maximum performance of your Wi-Fi, it is crucial to consider your needs before choosing the band and the channel for your requirements. The 2.4 GHz frequency in a Wi-Fi router enables a broader coverage of the area to penetrate through objects or walls at a maximum speed of 150 Mbps. However, this frequency is prone to interference and disturbances.

On the other hand, the newer of the two frequencies is the 5GHz that can provide a higher speed to handle minimal interference. It can be an ideal choice for internet connectivity at home. Crucial information on this frequency is its inability to penetrate solid objects, hence not considered a very successful band.

Different Wi-Fi standard supported in 2.4 GHz?

The 802.11 is a standard that has been around for a decade. Therefore the newer wireless technologies are built to support both the frequencies of 2.4 GHz and 5 GHz. Let’s dive in and look at some of the standards supported in the 2.4 GHz band.

802.11

The 802.11 is a standard for WiFi. This is the first WiFi standard was introduced in the year 1997.  The name was derived from the team that was responsible for its development. It supports up to 1 or 2 Mbps transmission capacity in 2.4 GHz band. This is the original IEEE standard. The more letters that get added signifies faster speed and performance.

802.11b

The standard 802.11 was further upgraded to 802.11b in 1999. This bandwidth supports 11 Mbps. The frequency remained the same at 2.4 GHz. For lowering the cost of production, the service providers prefer to have lower frequencies. As these networks fall into the unregulated network, the devices connected may have interferences from other devices such as microwaves, wireless phones, and connected appliances. However, 802.11b is rightly equipped to avoid any interference by maintaining the appropriate distance from other appliances. 802.11b is compatible with the g network. The backward compatibility allows for supporting more devices. The transmission speed is up to 11 Mbps in the 2.4 GHz band.

Pros: Low cost and the range of the signal is adequate without any disturbance.

Home appliances disturbance is possible and maximum speed is not sufficient.

802.11a

The extension of 802.11b is known as the 802.11a. The cost factor of acquiring an 802.11a frequency is higher as compared to 802.11b. It is commonly found in enterprise networks. The maximum bandwidth is 54 Mbps and comprises of a regulated frequency spectrum of 5 GHz. The drawback of this network is the coverage area, which is comparatively smaller than 802.11b. There is a difficulty faced with a higher frequency while penetrating walls and other obstructions in the room.

Faster speed, Regulated frequency.

Higher cost factor and lower signal range.

802.11g

This is perhaps the most popular network that offers speed and backward compatibility as well. It has a transmission speed of 54 Mbps and supporting the 2.4 GHz band. Thus, it is widely implemented in modern networks.

802.11n

It is commonly known as Wireless N. The focus was on improving the performance of 802.11g. When multiple frequencies are combined to achieve higher speed through antennas, it is called MIMO technology. It is backward compatible and offers a good range of coverage compared to earlier WiFi Stds.

This network type is the fastest among all of the available ones. The standard transmission speed is considered 100 Mbps, but it can support speed up to a staggering 600 Mbps in the right conditions. It is possible under the circumstances when multiple frequencies are used at once, and the speed is combined. The frequency is in the range of 2.4 GHz and 5 GHz.

For 2.4Ghz band Theoretical throughput is 300Mbps

For 5GHz band Theoretical throughput is 600Mbps

Highest rate, best among the signal range, no interference.

It is not yet finalized, costly, and multiple frequencies may cause interference with other networks based on 802.11g in the area.

Which frequency channels are allowed for 2.4 GHz and 5 GHz?

The 802.11 standard supports five frequency ranges: 2.4 GHz, 3.6 GHz, 4.9 GHz, 5GHz, and 5.9 GHz. These ranges are further divided into a group of channels. The allowable channel and maximum power level vary according to countries as per their regulations. In the USA, the licensed radio operators are allowed to use some of the channels at a higher power for covering a more comprehensive range of wireless access.

Illustration of the 2.4 GHz band channels.
Allowable channels in 2.4 GHz band in most countries

A total of 14 channels are accepted in the 2.4 GHz band. They are spaced apart by 5 MHz; however, an exception of 12 MHz exists before channel 14. It is crucial to highlight that in 802.11g/n, and orthogonal frequency-division multiplexing is not feasible. Hence it affects the number of possible non-overlapping channels for radio operation.

As the 2.4GHz band is 100 MHz wide, the allowable channels tend to overlap with each other. Therefore, it leads to interference in the Wi-Fi network. However, individual channels are capable of offering better performance because they don’t overlap.  The use of channels 1,6 and 11 or 1, 5, 9, 13 in specific nations are used in the 2.4 GHz spectrum. These channels allow us to remove cross channel interference possibilities as the channels cells are spread wide apart from one another.

On the other hand, in the 5 GHz spectrum, 24 channels don’t overlap. The cross-channel interference is tackled by placing the same channel access points away from each other. This ensures that the coverage area is divided into smaller cells, and each section consists of limited clients.

How 2.4 GHz has a more extended range than 5 GHz?

The coverage differs due to the nature of frequency. A higher frequency struggles to penetrate through objects. On the contrary, the lower frequency can pass through walls and other items easily. However, the data is transmitted quicker on a higher frequency as compared to the lower frequency. A higher frequency makes data downloading and uploading faster. Some of the major points are highlighted below.

2.4Ghz5Ghz
802.11b/g/n.
802.11a/n/ac.
A wider range of up to 300ft.The indoor range is significantly lower (~90 ft).
Compatible with most devices in general.Compatible with 802.11a/n/ac supported devices only.
Three non-overlapping channels.24 non-overlapping channels.
Congestion problems with Wi-Fi connectivity.Lower congestion as compared to 2.4GHz.
May face non-Wi-Fi interference.Lesser Wi-Fi interference.
Frequency band in 2.4Ghz and 5Ghz

802.11ac

This is the next generation among the available Wi-Fi networks. It comprises a dual-band wireless technology that can support both 2.4 GHz and 5 GHz frequencies. There is support for backward compatibility. The maximum speed falls in the range of 1300 Mbps on 5 GHz and about 450 Mbps on the 2.4 GHz.

Pros: Much improved bandwidth capacity, supports simultaneous frequencies and backward compatible

Cons: Costly and prone to interference.

What is Multiple-Input Multiple-Output (MIMO)?

Multiple-input Multiple-output (MIMO) is a form of wireless technology that consists of multiple transmitters and receivers that allows the transfer of an enormous amount of data at a single instance. Currently, MIMO

  • Is applicable only in 5GHz technology
  • 802.11n onwards WiFi stds only support this technology.

MIMO allows to achieve higher speeds as compared to devices with other network support.

Basic structure of a MIMO system in WiFi

To use MIMO, the access point and the station must have support for MIMO. A natural radio-wave called multipath is used for transmitting the signal. The signal can bounce off walls or ceilings and other objects, which passes on to the receiving antenna through various angles. Earlier usage of MIMO reported having faced problems related to interference and slowing down of signals. The addition of multipath in MIMO allows using smart transmitters and receivers to increase performance and signal range. The antennas’ purpose increases the receiver signal while combining the data streams from different paths at varying time intervals.

What is the modulation scheme?

Before we proceed to the modulation scheme, it is essential to understand the concept of modulation.

So what is modulation? Modulation is a necessary process that is associated with the conversion of data into electrical signals for transmission. There are primarily three types of modulation: amplitude modulation, frequency modulation, and digital modulation.

In general, wireless signals use adaptive modulation techniques. The advancement in technology has led to systems capable of supporting higher data rates in the network. The speed of transmission in modern devices is higher than older generation WLAN systems. There is a need for implementing different modulation techniques to achieve a higher speed of transmission.

Currently, a direct sequence spread spectrum (DSS) WLAN system uses binary phase-shift keying (BPSK) and quadrature phase-shift keying (QPSK) modulation techniques. These modulation techniques don’t meet the needs for higher data rate transmission. Thus, companies have started employing the more complex nature of modulation techniques. Some of the most common types of modulation techniques that support higher data rate transmission are M-ary orthogonal keying (MOK), complementary code keying (CCK), cyclic-code shift keying (CCSK), pulse position modulation (PPM), quadrature amplitude modulation (QAM), orthogonal code division multiplexing (OCDM), and orthogonal frequency division multiplexing (OFDM).

Orthogonal frequency division multiplexing (OFDM) existed in the older versions of Wi-Fi for single transmission type. The latest offering is Wi-Fi 6 supports both OFDMA and OFDM.

OFDMA is responsible for splitting up the Wi-Fi channels into a smaller set of frequency allocations known as resource units. This procedure aims to achieve better communication between the access point and multiple clients by assigning specific resource units. The channel’s division into various frequencies allows us to have improved video and audio streaming in a lag-free manner, thus enhancing the application’s performance. The OFDMA modulation technique is highly flexible as single clients may be provided the entire channel or perform the splitting as per the network traffic. The subcarriers of a channel are allocated to other clients for continuous transmission at a given time. The access point is responsible for the allocation of the channel or its subcarriers based on the need. Such a process allows for achieving effectiveness in the utilization of bandwidth. OFDMA is known to perform well in high-density environments. In total, there are 256 subcarriers in a 20 MHz channel, also known as resource units. 25, 52, 104, and 242 are the standard resource units available in a 20MHz channel and a minimum bandwidth allocation of 26 tone resource units that adds up to 2 MHz.

There are 256 subcarriers (tones) in a 20 MHz channel, and these groups of subcarriers are called resource units (RUs). The standardized resource units in a 20 MHz channel are 26, 52, 104, and 242. The minimum bandwidth allocation is 26 tone resource unit (RU) – approximately 2MHz.

A significant transition allowed the shift from simple analog amplitude modulation (AM) and frequency/phase modulation (FM/PM) to advanced forms of digital modulation techniques in recent years. Some of the examples of new modulation techniques are quadrature phase-shift keying (QPSK), frequency-shift keying (FSK), minimum shift keying (MSK), phase-shift keying (PSK), and quadrature amplitude modulation (QAM).

MSK is an improvement over QPSK. It has been successful due to the involvement of linear phase change. However, the spectral density is on the lower side lobes that help control adjacent channel interference.

QAM is another addition to the digital modulation techniques. It is used in applications like microwave digital radio, modems, and digital video broadcasting cable. Generally, there are four I value and four Q values, respectively. The result is a real possibility of 16 states for the signal, transmitting from any given state to any other state.

The most common type of phase modulation is QPSK. The most popular use of QPSK has been in cellular service, offering CDMA connectivity. The term quadrature refers to the shifting of phase states. The points are selected with the use of an I/Q modulator.

FSK is among the digital modulation techniques that involve changes in carrier signals based on the changes occurring in digital signals. Typically, the output comprises a higher frequency for high binary input and lower for low binary input.

PSK is the modulation technique in which the phase of the carrier is subject to changes by varying the sine and cosine input values at a given time. PSK techniques are most commonly found in wireless LANs, bio-metrics, Bluetooth technology, and RFID communications.

What is SSID?

SSID, does this term seem familiar? Probably yes, for people who have gone in-depth into the settings of the home based Wi-Fi connectivity. An SSID stands for a service set identifier. This is the most commonly associated with the 802.11 WLAN in the home network or a public hotspot. This allows for user devices to search for a wireless network to join.

 In simple terms, SSIDs are the names of your Wi-Fi network. If you have tried to access a Wi-Fi network publicly, you must have come across your wireless device with a list of names of the access network in the area. In most cases, SSIDs are displayed with a lock symbol that states the network’s security option is enabled. The SSIDs doesn’t have a common name as it can be changed when required. The majority of wireless routers allow disabling the SSID broadcasting to improve the security of the Wi-Fi network. With the possibility of discovering the SSID from the header of data packets in a router, this technique’s effectiveness is questionable.

 Cons of SSID

  • Easier access to the network with an SSID that does not have security options enabled.
  • A default SSID may create a clash with a nearby network with a similar name. In such a scenario, the network with a stronger link will connect instead of the desired network.
  • A flashy name of the network may invite unwanted attention from hackers.
  • An SSID may contain information that can be offensive.

What is BSSID?

Basic service set identifiers (BSSID) is a 48-bit identifier. It can be used to identify the access point or router because of its unique address. It can be simplified as the MAC address of a wireless access point. When there are multiple WLANs, there is a need to identify the access points and the client. Thus this identifier is included in the wireless pockets for this purpose. Ideally, as an administrator, you may supervise the activity within the BSS as you will acquire the information on the overloading of a network. With the help of a BSS, it is easy to locate the client. There is interlinking between the MAC address and the BSSID as all the packets contain the source BSSIDs. It is easy to identify the packet. However, it works well with a single radio and single WLAN configured.

How is a new network identified?

In specific cases, the wireless network doesn’t send out the SSID. A NIC may pick up the signal without a name for the access point. In such a scenario, you will be required to provide the name. The following steps may guide to identify a new network.

  • Access the control panel.
  • Select View Network Status.
  • Select the option to set up a connection or network.
  • Choose connect to a wireless network.
  • Click on the Next button.
  • Type the SSID into the network name option.
  • Select the security type from the security type button from the menu.
  • On the activation of the encryption type button, select the appropriate encryption from the menu.
  • Fill in the wireless network’s password in the security key text box.
  • Click next to connect with the network.
  • Select the connect to option.

Important terminology of wireless network

Wi-Fi 4

The standard 802.11n is also termed as Wi-Fi 4. This standard is considered as an upgrade over the 802.11g. MIMO technology was first introduced in this Wi-Fi standard. Due to the implementation of MIMO, a higher bandwidth rate of up to 150 Mbps is possible. The range of a Wi-Fi 4 device can achieve about 70 meters and 250 in outer conditions. The devices such as 2T3R and 4T4R are the Wi-Fi 4 devices with support for MIMO configurations. The modulation schemes that are used are QPSK, BPSK, 6QAM, and 16QAM. It supports both the frequencies of 2.4 GHz and 5 GHz.

Wi-Fi 5

802.11ac standard by IEEE is what is known as Wi-Fi 5. This standard includes support for multi-user MIMO features. It supports a higher bandwidth along with higher spatial streams and higher throughput. The modulation schemes are on the higher side at 256 QAM. Wi-Fi 5 works on a 5 GHz frequency. The data transmission rate supported is up to 3.4 Gbps. Several bandwidth channels are supported, such as 160 MHz, 20 MHz, 80 MHz, and 40 MHz. There is support for multi-user and single-user transmissions, respectively. The expected range of coverage is between 80 meters and three antennas.

Wi-Fi 6

So why is there a buzz about Wi-Fi 6, and why it matters?

Wi-Fi 6 is the newest addition to the wireless standards, which is expected to be faster than 802.11ac. This new standard is known as 802.11ax. Speed, along with performance, is the focus area of this new standard. With the capability of providing uninterrupted speed in congested areas to football stadiums or your home network, Wi-Fi 6 is well equipped with modern technologies incorporated into it. Although it was officially released in 2019, the specialized hardware is releasing gradually in 2020.

The latest Wi-Fi standard has the fastest data transfer speeds among the other standards. The expected difference in speed on a single device is about 40% higher than the Wi-Fi 5 standard. It has been possible to reach such speeds due to the efficient encoding of data that results in better throughput. The encoder and decoder mechanism is more powerful that allows handling additional work. The new standard has been found to increase the speed even on a 2.4 GHz frequency. Although there has been a steady shift towards the 5 GHz frequency, the 2.4 GHz is still considered to be among the best in penetrating solid objects. The scope of interference has been reduced as old generation technology such as cordless phones no longer exist in the market today.

Let’s deep dive further and have a look at some of the possible benefits of Wi-Fi 6.

  • Improved battery life: The likes of the Internet of Things (IoT) have led to smarter devices’ innovations. The introduction of a new feature called target wake time is responsible for handling the Wi-Fi enabled devices’ wake-up time. This feature can communicate with the device when the device needs to sleep and wake up on receiving a transmission. Using this feature will save power as it will be in sleep mode during idle conditions, thus longer battery for your smartphones, laptops, and tablets.
  • Performance enhancement in crowded areas: Often, you may have come across situations wherein a busy and congested area tends to interfere with the connectivity. There are multiple devices in such surroundings. It is common in places such as markets, malls, stadiums, hotels, or airports. As per Intel’s reports, Wi-Fi 6 is expected to increase the user’s average speed by a minimum of 4 times from earlier performance rates in a crowded place. It will also be applicable if you are using at home with multiple devices connected at the same time or if you are living in an apartment complex with various networks and people.

How does Wi-Fi 6 tackle congestion?

Wi-Fi 6 is designed in a way that has divided a wireless channel into multiple sub-channels. The sub-channels carry data to be transmitted to another device. This process is achieved through a new technology feature called orthogonal frequency division multiple access (OFDMA). It allows for an access point to communicate with many devices at a single time. MIMO has been improved significantly than the previous generation with multiple antennas. Although Wi-Fi 5 let the access points to communicate with other devices, the devices couldn’t respond in return. This factor has been improved in Wi-Fi 6 with MU-MIMO, allowing the devices to communicate with the access points simultaneously.

Conclusion

Wi-Fi has become an integral part of our daily lives and how we operate in the personal and professional space. The introduction of newer standards has significantly improved the connectivity and speed factors needed to be addressed in time. As technology evolves, it is highly likely to expect better and smarter standards that will incorporate artificial intelligence and IoT to an extent to improve user experience beyond an unimaginable point in the future.

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