IEEE 802.11 Wireless LAN

Introduction

IEEE 802.11 Wireless LAN contains several kinds of Media Access Control (MAC) and physical layer (PHY) protocols that improve communication between computers across Wireless Local Area Networks (WLAN). The rules and changes rank among the majority of widely used wireless networking standards for computers today and serve as the foundation for wireless networking technology that carries the WiFi band. To provide wireless communication and connectivity via internet access amongst computers, printers, cell phones, and several other electronics, a great deal of home and office networking uses IEEE 802.11. IEEE 802.11 is the basis for enabling vehicle-based communication networks also.

These IEEE 802.11 specifications have significantly influenced the development of wireless networking methods, allowing wireless communication to proliferate across a variety of devices, from desktops and cell phones to Internet of Things (IoT) gadgets and automated homes. The 2.4 GHz, 5 GHz, 6 GHz, and 60 GHz ranges of frequency constitute just some of the available frequencies where the IEEE 802.11 protocol can be used. Although the IEEE 802.11 specifications provide potential paths, each governmental jurisdiction has a significantly different available radio frequency bandwidth. The foundation of 802.11 technology lies in this choice.NCR Corporation and AT&T started working on the forerunner to 802.11 at Nieuwegein, the Netherlands 1991. The technique was initially intended to become widely used in the cashier apparatus created by the developers. Early wireless networking technologies bearing the brand WaveLAN entered the marketplace by utilizing raw data speeds.

History

In 1985, the United States Federal Communications Commission announced a judgment allowing unlicensed ISM band utilization. The foundation of 802.11 technology lies in this choice. NCR Corporation and AT&T started working on this at Nieuwegein, the Netherlands 1991. The technique was initially intended to become widely used in the cashier apparatus created by the developers. Early wireless networking technologies bearing the brand WaveLAN entered the marketplace by utilizing raw data speeds.

Vic Hayes, who has been referred to as the "father of WiFi" and served as head of IEEE 802.11 for over 10 years, was responsible for developing the initial 802.11b and 802.11a standards inside the IEEE. He and Bell Labs engineer Bruce Tuch addressed IEEE to develop a standard.

Common misunderstandings about achievable throughput

The maximum achievable abilities of the vast majority of 802.11 versions have either been expressed according to discoveries made under ideal circumstances or quantified in terms of layer-2 data transfer rates. Seems to be outside typical deployments, in which data is transferred between a pair of computers, often connected to a connected infrastructure and the other to a wireless network. It also means that communication sessions often transform from 802.11 (WLAN) to 802.3 or vice versa while they move over the channel. The application's packet quantity governs the information transfer velocity since both mediums' frame (header) sizes fluctuate.

As a result, VoIP and other short-packet technologies produce data streams with significant overhead traffic. The rapidity with which the software communicates each packet, its information pace, and the power from which the transmitted signal arrives were additional aspects that influenced the application as a whole data transfer rate. The latter parameter is based on both the adjusted power supply of the gadgets that are communicating and the distance between them. The diagrams in the attachment that display assessments of UDP bandwidth use the same standards. Every measurement displays the average throughput (UDP) across 25 measurements; the bars with errors are included, although they are hardly noticeable considering the little fluctuation. Each one has a distinct data rate (10 kbit/s to 100 mbit/s) and packet size (tiny or big). Additionally, there are identifiers for the visitor profiles of popular programs. These numbers assume there are no packet errors, which, if present, would further decrease the overall transmission efficiency.

Channel spacing within the 2.4 GHz band

The 802.11 standard also includes (in Clause 17) a spectral mask that outlines the allowed power dispersion throughout every channel and the channel's centre bandwidth. The transmitted signal must be attenuated at least 20 dB beyond the greatest amplitude at 11 MHz from the centre of the frequency, which happens to be when a channel's width is 22 MHz wide, in order to pass beneath the mask. As a result, broadcasts are limited to using each fourth or fifth channel without overlapping.

Channel accessibility varies by nation and is restricted by how a nation distributes its radio spectrum among different service providers. Japan allows the simultaneous use of 14 channels for 802.11b and 1 through 13 for 802.11g/n-2.4. Yet Europe currently permits channels 1 through 13, unlike other countries, including Spain, which originally limited access to channels 10 and 11, and France, which previously permitted channels 10, 11, 12, and 13. Only 1 through 11 is permitted in North America and certain Central and South American nations. IEEE's primary AIM is fostering excellence and creativity in technology for the betterment of humanity. The Internet and its associated technologies must conform to a particular list of rules and standard procedures for all networking equipment to function properly and for interactions among different gadgets to be guaranteed by the IEEE standards for computer networks. The IEEE's Computer Organization launched Project 802 in 1985 to facilitate a uniform interface across different gadgets owing to the wide range of computer equipment suppliers.

IEEE Standards for Computer Networks

Let's begin by studying the IEEE before diving into the IEEE requirements for computer networks. Many scientists, engineers, and learners across many countries make up the IEEE.

LANs serve as the main application for the technology, along with the protocols that make up Ethernet. The IEEE 802.3 standard originally regulated it in the 1980s. For wired Ethernet networks, IEEE 802.3 specifies the physical layer and the communication link layer's medium access control (MAC) sub-layer. Ethernet is divided into two types: Switched Ethernet and Traditional Ethernet.

The Internet, along with its associated technologies, must conform to a particular variety of rules and recommended procedures to enable all networking equipment to function properly and for interaction between different gadgets guaranteed by the IEEE standards for computer networks. The IEEE Computer Society launched Project 802 in 1985 to facilitate uniform communications across different systems because of the diversity of computer system manufacturers. The data link layer was separated into two sections for the purpose of this project: the IEEE, notably.

• LLC or Logical Link Control
• MAC or Media Access Control

The IEEE 802 wireless standards include those that deal with computer networking (and networking in general). IEEE 802 comprises a group of network protocols covering Ethernet and wireless technologies as well as data link layer technologies.

Variety of IEEE standards in Computer Networks

Computer networks use a variety of IEEE standards. Let's get started by becoming familiar with three important IEEE standards.

• IEEE 802: The LAN (local area network) and metropolitan area network (MAN) technologies are covered under the IEEE 802.
• IEEE 802.1: The IEEE 802.1 is concerned with LAN and MAN specifications. Additionally, it addresses MAC (Media Access Control) bridging.
• IEEE 802.2: The LLC (Logical Link Control) is a topic covered by IEEE 802.2.

Let’s start to use one of the IEEE standards for computer networks as a case study. Many common household items, including laptops, printers, smartphones, and other electronic gadgets, employ the IEEE 802.11 standard for computer networks, enabling Internet-based communication. Therefore, wireless communication equipment, such as WiFi bands, benefits from the IEEE 802.11 standard in computer networks.

Frames used by IEEE 802.3 and Traditional Ethernet

• Preamble: The very first area of a transmission serves as a warning and timing pulse. It comprises an 8-byte field for traditional Ethernet and a 7-byte sector for IEEE 802.3.
• Start of Frame Delimiter: A single byte field in an IEEE 802.3 framework consisting of a changing sequence of both ones and zeros and ends with two ones is called the "start of frame delimiter."
• Destination Address: This field is 6 bytes and contains the actual physical addresses of stations' targets.
• Source Address: The transmitting station's physical location is in a 6-bit field.
• Length: A 7-byte field is used to record the size of this information field.
• Data: The information from the topmost layers is carried via this variable-sized field.
• Padding: The following is included in the data in order to increase its size beyond the required limit of 46 bytes:
• CRC: A cyclic redundancy check is referred to as a CRC. It includes data about the identification of errors.

Local Area Networks (LANs), which employ high-frequency radio waves rather than wires for linking every device within the LAN, are commonly referred to as wireless LANs. Users attached via WLANs have mobility over the wireless network's coverage region. Most WLANs are centred on the IEEE 802.11, or WiFi, standard.

The IEEE 802.11 Architecture

1. Stations (STA): All hardware and software used for linking to a wireless local area network is referred to as a station (abbreviated as "STA"). There are two categories of stations:

• Wireless Access Point (WAP): The wireless routers that serve as the base installations or entry are commonly referred to as WAPs or simply points of access (AP).
• The Client: Clients include desktops, laptops, printing devices, mobile devices, and other electronic devices.

A station, also known as an STA in IEEE 802.11 (WiFi) parlance, represents a piece of equipment that can utilize the 802.11 protocol. For instance, a station could consist of a laptop, desktop PC, PDA, connection point, or WiFi phone. A STA might be stationary, moveable, or portable. A station, a wireless client, and a device known as a node tend to be used synonymously within wireless networking terminology; there needs to be a clear differentiation among these words. Depending on its broadcasting properties, a station could be known as either a transmitter or a receiver. According to IEEE 802.11-2007, a station is any gadget with a media access control (MAC) and physical layer (PHY) interface that complies with IEEE 802.11 standards regarding the wireless medium (WM).

A wireless network interface processor is present on every station.

2. Basic Service Set (BSS): A basic service set is a group of stations communicating at the physical layer level. BSS can be of two categories depending upon the mode of operation:

• Infrastructure BSS: The devices communicate with other devices through access points.
• Independent BSS: Here, the devices communicate on a peer-to-peer basis ad hoc manner.

3. Extended Service Set (ESS) is a set of all connected BSS. A single AP and a single STA make up the most fundamental BSS. A common service set identification (SSID) is required for a broader assistance set comprising various BSSs. The BSSs may operate on either the identical channel or other channels. It assists in strengthening communication over the entire wireless connection. An 802.11 wireless LAN (WLAN) comprises just one service set comprising all STAs that acquire transmissions via a specific AP. Each STA might pick up a signal through several APs that are in the range of it. Each STA can manually select the network it wants to be associated with or via automation, depending on how it is configured. Additionally, as an essential component of an expanded service set, many APs may use the same SSID.

Although not part of the 802.11 standard, some wireless APs may broadcast multiple SSIDs, creating virtual access points – each with security and network settings.

4. Distribution System (DS): It connects access points in ESS. The term "distributed system" describes a group of independent computing devices that link together through a centralized computer network using distributed system software despite being physically distinct. All of the system's autonomous machines will interact with one another by exchanging files and resources while carrying out the duties given to them.

Example of a Distributed System:

Each social media platform might possess a centralized computer network serving as its administrative office, along with autonomous systems in a distributed system framework that any individual may utilize to employ their offerings.  

• Distributed System Software: This Software enables computers to coordinate their activities and to share resources such as Hardware, Software, Data, etc.
• Database: It is used to store the processed data processed by each Node/System of the Distributed systems connected to the Centralized network.

Advantages of WLANs

• They additionally offer clutter-free residences, workplaces, and other associated locations.
• LANs are more expandable over wired LANs, meaning that gadgets can be introduced to or deleted through the network's infrastructure with less difficulty.
• The equipment is transportable across the network's coverage; hence, cables do not constitute a barrier to accessing the network.
• The equipment & setup expenses were less compared to equivalent wired systems.
• Installation and configuration are simpler.

Disadvantages of WLANs

• Because radio waves are utilized as interactions, there is greater disturbance between surrounding systems, making the sounds louder.
• Information encryption needs to be done with more care.