An Overview Of Wifi And How It Works
Being able to connect seamlessly to the internet has become an integral part of our lives. Technology has advanced hence we have moved from an age that involves a lot of tangled cables to wireless connectivity particularly Wi-Fi. This is where radio waves have proved to be useful. From telephone networks, television broadcasting to Bluetooth. These applications in radio waves have influenced the development of Wi-Fi technology in one way or another. Almost every gadget today has the ability to connect to the internet via a Wi-Fi connection. Including smartphones, computers, miniature drones, smart TVs, automobiles and even printers. Not only is it cheap, but also a convenient mode of connecting to the internet. Today, a Wi-Fi hotspot can be found in about any public place. From learning institutions, lobbies, hotels, airports, etc. You can as well have a private Wi-Fi network at home or one that is portable. Smartphones and computers can also create hotspot. You may be intrigued by how Wi-Fi works or how data is able to travel through a wireless medium. We have taken a comprehensive look at what Wi-Fi is and how it works.
What is Wi-Fi
Wi-Fi is a wireless technology that harnesses radio waves to transmit data wirelessly between two or more connected devices. Instead of transmitting signals via a cable, it is sent through the air. Wi-Fi is an acronym that stands for Wireless Fidelity which means the degree of accuracy of the signal. Well, this term is not widely known or used hence in a way it has been replaced by its abbreviated name.
Every Wi-Fi connection has a two-way route for data communication. One way is dedicated to outgoing messages while the other way is dedicated to incoming messages. Basically, when two devices are connected, data can be sent back and forth. To prove this concept, you will always see two arrows next to the Wi-Fi signal icon. One arrow pointing down while the other pointing up. Arrow pointing up represents data being sent from the respective device, while the arrow pointing down represents data being received by the device. Radio waves used in Wi-Fi technology is different from traditional radio waves used in other communications in that, Wi-Fi uses higher radio frequencies to increase the rate of data transmission.
Different Wi-Fi protocols come with different Wi-Fi standards. These standards come in the IEEE 802.11 family of standards. The introduction of wireless connectivity using Wi-Fi dates back from as early as 1971 with the Great Hawaiian islands being the first to make this step. The initial version of the 802.11 standards was released in 1997.
Wi-Fi fi Standards
The different Wi-Fi standards mean a difference in Radio technology used in each standard. Consequently, a difference in speed, range, and bandwidth. Usually, Wi-Fi signals operate between a 2.4GHz (Gigahertz) to 5GHz bandwidth depending with the standard. To minimize interference, these bandwidths are usually broken down into channels using TDMA (Timed-Division Multiple Access) and OFDM (Orthogonal Frequency-Division Multiplexing) technologies. This allows multiple users to access the same frequency and transmit at the same time. The various standards are known as IEEE 802.11 with a letter at the end representing the specific standard.
Here are the main 802.11 Wi-Fi standards as set by IEEE (Institute of Electrical and Electronics Engineers):
- 802.11a: This standard can transmit data at a rate of up to 54Mbps (Megabits per second). Although at normal circumstances and constraint factors being present, it usually transmits at a rate between 6 and 24Mbps. Radio signals are transmitted at a frequency of 5GHz. 802.11a has incorporated orthogonal frequency-division multiplexing technique to reduce interference. Although this standard has a higher rate of data transmission, it has been noted that it is more prone to obscuration and absorption by concrete walls and other materials due to its small wavelength. This greatly limits its range in premises with a lot of walls. Hence it is more effective for direct line-of-sight connections.
- 802.11b: This standard is a bit slower. Rate of data transmission is up to 11Mbps. Radio signals are transmitted at a frequency of 2.4GHz. This may seem low but the overall range of this standard is higher than that of 802.11a. The main cause of interference to this standard are devices operating at the same 2.4GHz frequency including cordless telephones, Bluetooth, microwaves, etc.
- 802.11g: This standard operates at a 2.4GHz frequency as 802.11b. The difference is it implements orthogonal frequency-division multiplexing. As a result, it is able to transmit data at a rate of 54Mbps. Which is an average of 24Mbps during normal circumstances. Just like 802.11b, this standard is affected by equipment transmitting radio waves at the same frequency
- 802.11n: This is a more advanced standard to its previous counterparts. 802.11n adds a technique called MIMO (Multiple-Input Multiple-Output). This technology expands its capacity by use of multiple transmitters and receivers. This enables sending and receiving multiple radio signals all at once. It is able to operate at both 2GHz and 5GHz frequencies. Its theoretical rate of data transmission ranges between 54 and 600Mbps.
- 802.11ac: also known as Wifi 5, this standard sends signals at a frequency of 5GHz compatible with more modern devices.
Various protocols and technologies have been combined to come up with other standards.
How Wi-Fi Works
To get a better understanding of how Wi-Fiworks, we have broken down this topic into a series of subtopics.
Requirements for a Wi-Fi Connection
A typical Wi-Fi connection consists of hotpot (or an Access Point) and a Wi-Fi enabled device known as a client. A hotspot is an area where Wi-Fi can be accessed. A router is the most common device for setting up a hotspot. In order for the network to have an internet connection, the router has to be connected to an ISP (Internet Service Provider) using a modem. You can also connect an internet cable to your wireless router. Router to router connection can be done as well, with one router being able to connect to the internet and sharing to the other router.
For your device to connect to a Wi-Fi network, it needs to have a network adapter or a network interface card. The network adapter supports both wireless Wi-Fi connection and wired Ethernet connection. Today, network adapters have been enhanced to be able to decode USB tethering. It is important to note a Wi-Fi connection can be established even without the network having an internet connection. For example, having two mobile devices connected via direct Wi-Fi then sharing files or a connection between your desktop and printer. Data exchange will happen between these devices without internet. This is known as an Ad-hoc network.
How Does a Network Adapter Work
The network adapter is also known as NIC (Network Interface Controller), network interface card or a LAN adapter. These terms basically mean the same so don’t be confused when you see them used interchangeably in different write-ups.
To understand how a network adapter works, we must dissect its components. The network adapter consists of the transmitter, receiver and necessary circuitry and software for encoding and decoding data. Having looked at its components, we can establish its functionality as follows:
- Encodes data into radio waves which are sent using the transmitter.
- Decodes radio waves that are received via the receiver into a form that is understood by the device.
- The network adapter also handles buffer storage.
All this is conducted with the help of the seven network layer protocols depending on the standard used. The transmitter and receiver are what creates the two-way route. The link can be established with the means of a wired connection (e.g. USB tethering or Ethernet) or wireless connection (i.e. Wi-Fi ). Most computer motherboards come with an expandable slot for the network interface card. Conversely, if your computer does not have the required slot, an external USB Wi-Fi adapter can be used for wireless connectivity.
How Data is Sent Using Wi-Fi
You might have heard of the term network packet (data packet or simply a datagram). This is a small chunk of data that is usually sent over a network whether wired or wireless. Before data such as a message, email or a large file is sent over a Wi-Fi connection, it is first split into smaller fragments called packets. These chunks are then collected and merged on the receiving end to come up with the original data chunk. This explains the importance of buffer storage. These packets not only carry pieces of the original data but also contain other essential information as well. Every data packet is sent along with the necessary information that will enable it to reach its intended destination.
When a data packet is created, it is marked with the physical address (otherwise known as Mac address) of the receiving device. The packet is then relayed through the air by use of radio waves. It is not sent to any particular device, therefore, any Wifi enabled gadget within range will be able to receive this packet. Only the device with the matching Mac address as specified along with the packet will be able to process and retrieve the data. Once the chunk is received, a message is sent by the receiver to acknowledge the successful reception of the packet. Then the next packet is sent. The process continues until all the data goes through.
For communication to go beyond the router and into the internet, a service called DNS (Domain Name Service) is required. This service is responsible for mapping all existing domain names into their corresponding IP addresses. For example, when you search for ‘google.com’ on your computer, for you to receive a response the DNS is required to give the corresponding IP address. The reason for this is because networked devices can only establish communication by use of IP address and not domain names. Domain names are used to enhance readability and remembrance to humans. Imagine having to remember and type in the IP address of a website every time you want to visit. Take a look at it this way, the internet is made up of millions of computers and servers each with its own unique IP address that corresponds to its domain name. Therefore, it is necessary to convert the domain name to an IP address before a connection to the remote server is established.
DNS service is run by your internet service provider on a DNS server which keeps a huge record of existing domain names and their corresponding IP address. When you type the domain name or simply the URL (Uniform Resource Locator) on your browser address bar, your device sends a request know as DNS query to your ISP DNS server to resolve the domain name to its IP address. This process is very rapid and takes place in the background. It often goes unnoticed. The response with the IP address is received by your device in a split second. Wi-Fi technology has come a long way. With its advancement over the years, a variety of trends have emerged today. Ambitious plans and active development are still underway to improve this technology and its application in a wide range of areas. What has been achieved so far is quite breathtaking.
IoT (Internet of Things)
This is a Wi-Fi trend that is rising very fast. The ‘thing’ in the internet of things may be an automobile with sensors to alert the driver of a suitable route, a piece of autonomous farm equipment guided by GPS or even an animal tagged with a tracking device. A simple example is a remote printer connected to your desktop at your workplace. Other wireless technologies apart from Wi-Fi have been used to achieve IoT. Imagine having a house whereby all your devices and equipment are interconnected and centrally controlled with your computer or mobile phone. This means that household equipment such as fridge, TV, sound system, microwaves, and even your vehicle can exchange data. You can switch on or tune your sound system even without having to interact with it. Internet of things has been used in a huge scope of industrial applications. With the advancement in IoT, it has been necessary to introduce new protocols.
Various software designated for IoT devices has been developed including Riot OS and Thingsquare mist. Riot is an operating system belonging to IoT devices. Thingsquare is an open source firmware that has been applied in a number of mesh networks and other IoT networks. It brings internet connectivity in IoT. There are also cloud service providers for complex IoT setups including ThingWorx and Everything. IoT has even adopted machine learning to bring about autonomous interconnected devices. Popular software that has been used is the Gork engine.
As the name suggests, mesh networks are formed by links established between multiple nodes. Each node acts as a router being able to communicate with its intermediate nodes as well as client devices connected to the network. Generally forms a mesh topology. This trend has proved effective when dealing with Wi-Fi dead zones as well as increasing range without losing significant signal strength. With mesh networks, high performance and broadband networks can be set up at a low cost.
A Mesh network may operate in one of the following three protocols:
- Proactive protocol: nodes constantly communicate with each other and inform each other in case of path changes such as removal of one node. This enables it to recover from failure. In the case of a dynamic environment where nodes are moving too fast, more resources are used for path reordering which may result in low bandwidth and increased collision. It is more applicable in static environments.
- Reactive protocol: With this protocol, connections are established on demand. This results in the best and shortest paths possible.
- Hybrid: Has the features of both proactive and reactive.
Recently, reports show Mesh networks have experienced an increase in market share compared to traditional stand-alone access points. These networks cannot be added to your existing router therefor it is meant to replace it. Large scale mesh networks are able to span an enormous area such as a whole city. Cool and portable mesh nets designed for indoor use have hit the market. From the Google Wi-Fi, Tenda Nova to the NetGear Orbi. There are also many other pocket-friendly mesh nets out there.
This is the next generation Wi-Fi standard (Wi-Fi 6 in layman) that is said to be four times faster than 802.11ac. Although this standard has not yet been adopted fully. This standard has been developed with the aim of enhancing efficiency. Talk of battery life and a reduction in latency. 802.11ax is set to operate at all bandwidths between 1 and 7GHz which is a huge step from the 2.4-5GHz range. To improve efficiency in terms of power consumed and an increase in throughput, this version utilizes OFDMA (Orthogonal Frequency-Division Multiple Access) which is a multi-user version of the OFDM. So far only a few devices have incorporated this standard including the Samsung Galaxy S10.
We have come far from a time when we struggled to download a single image file to now streaming video files in high definition. People can now video chat in real time without losing connections. High-speed connectivity has also played a key role in gaming and virtual reality. Right now developments are underway to come up with the next generation 5G speed. Imagine the possibilities that can come with this kind of connection. Communication latency could be a thing of the past.
Wi-Fi technology has been enhanced over the years to be compatible with more devices. Multi-band enabled devices have the capability of transmitting Wi-Fi signals at more than one bandwidth. Multiband Wi-Fi technologies that are present are Dual-band and Tri-band. Dual-band routers and devices are able to broadcast Wi-Fi signals at both 2.4 and 5GHz spectrum hence able to support client devices that are confined to the older 2.4GHz as well as devices operating at the modern 5GHz spectrum.
Tri-band routers and devices can broadcast three different bandwidth frequencies. One of the frequency is at 2.4GHz while the rest of the two are at 5GHz. This means it supports more devices that can be able to connect to the router. This will not increase speeds on individual devices although it will maintain the speed even when more devices are connected since there are more signals to connect to.
Drawbacks of Using Wi-Fi
While Wi-Fi technology has its advantages, it has its fair share of problems as follows:
- Security: Wireless networks are more susceptible to malicious attackers compared to wired networks yet many businesses neglect this security issue. All that is requires to carry out an attack is to join that network. Public Wi-Fi networks are rated with the highest risk. Even private networks with weak passwords can be exploited. Expert hackers are able to intercept sensitive data belonging to other users.
- Range limitation: A Wi-Fi signal gets weaker with an increase in distance. The decrease in signal strength may be as a result of interference by other radio waves transmitted at the same frequency. Loss of signal can also be due to absorption by blocking materials such as concrete walls. Even without these factors, radio signals always lose strength naturally with distance.
- Speed: Compared to a wired Ethernet connection, Wi-Fi connection is relatively slower.
- Reliability: May not be reliable when many devices are connected. Wi-Fi is prone to slow connections especially when there is high interference or when there is a large number of client devices connected. This means there is a limited maximum number of users able to connect at one time. Slow connections may as well be experienced due to ISP throttling. This is whereby the internet service provider limits the maximum data rate to prevent server overload.
- Cost: In some instances, it may be costly to set up a wireless network compared to a wired network. Getting a decent reception from an internet service provider is costly as well. Cheaper alternatives are available but are less reliable especially when in an overcrowded network.
Wi-Fi has brought convenient and seamless connectivity which has, in turn, made a big impact on information sharing. It is evident that advancement in Wifi technology is not going to stop anytime soon. It is therefore prudent to note that being able to connect on the go bring negative impacts such as cybercrimes and exposure to sensitive information.
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