History About Wifi Technology Information Technology Essay

ABSTRACT

In many of the industrial sectors, the wireless networking technologies are gaining rapid approval because of its cost effectiveness, improved reliability and flexibility. The increase in the wireless networks is one of the technological advances that are having a major impact on the way we do business [10].

This paper refers how Wi-Fi technology is organized and some of its applications and advantages over customary means. It also explores how Wi-Fi technologies communicate in the spread spectrum and also its configurations. The Wi-Fi refers to the 802.11b wireless Ethernet standard that was designed to support the wireless LANs. The essential enabling technology is the Wi-Fi technology and it is the only practicable infrastructure for the home which allows the user to extend their networks for home entertainment. The most popular user access technology is the Wi-Fi (WLAN/IEEE 802.11) because of its high bandwidth and low cost.

Keywords: Wireless Fidelity, Wi-Fi, WLAN, wireless technologies, IEEE 802.11a/b/g, spread spectrum, configurations.

Introduction

In the recent years only, the wireless technology has grown rapidly which allows the users more reliable, effective and can access the internet without using the wire. Wireless networks are more effectively used in many applications such as home entertainment, offices, radio, military areas and public places. The term wireless does not mean the disturbance or group of switches. Wireless means the communication without the use of wires other than the antenna, the Ethernet, and the ground taking the place of wires [2]. For several industrial operations, wireless technology affords cost-effective and effective connectivity solutions. Using the wireless technology there are many benefits such as remote facilities, processes and field operation which results in improving productivity, downtime, faster and more accurate data collection.

The term Wi-Fi technology is also referred as “Wireless Fidelity”. The Institute of Electrical and Electronics Engineers Inc. (IEEE) is the association liable for setting the standards on how the technology and products works, operate and communicate [3]. The 802.11 technology standards, better known as Wi-Fi technology and it is being set up into the Broadband Wireless Access (BWA) equipment and Local Area Network (LAN) access points to quickly connect computer to LANs and as well as internet service providers. The 802.11 standards are growing to supply a higher data rates and better quality of service. Wireless LANs operates on two frequencies such as radio wave and infrared. In the past decades, the wireless access point has come into the market with infrared but in today’s world the radio frequencies are used most popularly. The advantage of the radio wave frequency is more penetrate through the walls, floors and doors but whereas the infrared device is on line of sight. Wi-Fi network connect computer to each other to the internet and to the wired network.

1.2 History of WLAN

A WLAN is a local area network without wires and whereas a wired network in which the clients send/receive the data through the cables. The wireless network uses a radio wave frequency. As part of the large family of the spread spectrum systems, the Wi-Fi technology uses single carrier direct-sequence spread spectrum radio technology and multi-carrier OFDM (Orthogonal Frequency Division Multiplexing) radio technology. In 1985, the unlicensed spread spectrum was first approved by the Federal Communications Commission (FCC) [5]. In all major countries, these FCC regulations were later copied with enabling some changes in the use of this technology and these regulations were then enabled the growth of Wi-Fi technology according to requirements such as offices, online games and so on.

In 1991, the Wi-Fi technology was invented by NCR corporation/AT&T (later Lucent and Agere systems) in Nieuwegein, the Netherlands. Initially for the cashier systems, the first wireless product were brought on the market which is marked as WaveLAN with speeds of 1Mbits/s to 2Mbits/s. Vic Hayes, who was the first discoverer of the Wi-Fi and later has been named as ‘Father of Wi-Fi’, was involved in designing standards such as 802.11a/b/g. Wireless LANs communicate via the 2.4 GHz or 5GHz band with the unlicensed Industrial, Scientific and Medical (ISM) radio bands where cordless phones, instant monitor and other personal device can also operate. According to Mr. Phil Belanger of the Wi-Fi Alliance contradict the most popular conclusion that Wi-Fi stands for “Wireless Fidelity” [5].

1.3 Benefits of WLAN

A new way to communicate with the user is through the WLANs while accommodating the way business is done. The following are the benefits achieved through WLANs:

Mobility within building.

Flexibility

Lower cabling costs

To set up temporary spaces, it is easier

Productivity gains

Reduced errors

Improved efficiency

Improved performance, efficiency and security for enterprise partners and guests

Easier to collaborate

Easier adds, moves and changes and lower support and maintenance costs

More efficient use of office space.

Wireless Fidelity (Wi-Fi) Technology

The IEEE 802.11 standard was projected for the WLANs. To handle the networking the short way for Wi-Fi is the wireless. Wi-Fi is easy to access and it is very simple to connect to computer anywhere in the office or homes without the use of wires. Using the radio signals the computer connects to the network. In 1997, the first standard (802.11) was released and works in the frequency band at 5GHz with the data rate of 54Mbits/s and uses the OFDM (Orthogonal Frequency Division Multiplexing) modulation [4]. The Carrier Sense Multiple Access/ Collision Avoidance (CSMA/CA) is the media access method.

The term 802.11.x terms is used to donate the set of amendments to the standard. Within the scope of one building and one room, we can connect to the wireless to the restricted signal range (indoor range is approximately about 1m).

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Figure 1: Internet connection with wire and without wire (Wi-Fi)

At present, the best values of the bit rate have a networks designed accordance with the 802.11n standard that has the typical raw data rate of 540Mbits/s [3]. Wi-Fi network operates in the unlicensed with the 2.4 and 5GHz radio bands, with 11Mbps (802.11b) or 54Mbps (802.11a) data rate or some of the products have dual bands. Wi-Fi network uses radio technologies to transmit and receive the data at high speed.

IEEE 802.11 is available in three modes- 802.11a, 802.11b and 802.11g. IEEE 802.11a/b/g actually describes three different wireless Ethernet standards which are currently implemented in industrial applications as well as commercial applications. These three alternatives are based around the same physical layer of the OSI model and it also defines the bands on what the wireless network is used and also defines the modulation technique. IEEE 802.11 standards include “Wi-Fi”, “W-LAN” and “Wireless Ethernet”.

IEEE 802.11a:

This standard operation is used in OFDM which operates at a frequency of 5GHz band and thereby allowing the raw transmission data rate up to 54Mbps. It is introduced in 2001. For this band, some of the countries have other uses such as military and air traffic control, so therefore this band is not globally accepted and to be used in the ISM applications. But in some cases, this band can be used inside the building with limited power. In the U.S, the band 5GHz is treated as other 900MHz and 2.4GHz ISM bands. One advantage of the IEEE 802.11a is that it operates with same data rate (54Mbps) as IEEE 802.11g but it escapes sometimes due to crowded with the 2.4GHz channels. Less interference in the 5GHz band appears means the potential for more reliable transmission. The theoretical speed of this standard is 54Mbps but the raw transmission rate of this standard is in between 15-20 Mbps. The range of this standard is 50-75 feet. This is not compatible with 802.11b and it is more expensive.

IEEE 802.11b:

This standard was implemented in 1999, uses 2.4GHz band with the DSSS (Direct Sequence Spread Spectrum) modulation. The maximum transmission rate of this standard is 11Mbps within 30m range. It is most popular and least expensive. But the actual speed of this standard is 4-6 Mbps. The range of the wireless is 100-150 feet. The subsection of this standard is called “Wi-Fi”.

IEEE 802.11 g:

The OFDM technology of 802.11a is adopted in this standard and which is globally accepted with 2.4GHz band. Using the OFDM technique these data rates increased to 54Mbps over the air. It is important that 802.11g is compatible backwards with 802.11b. But this standard is more expensive so prefer to go for the least expensive and better performance which is 802.11b.

Components of Wi-Fi:

In order to access the Wi-Fi, we require some of the components such as adapters, access point, Wi-Fi antenna, Wi-Fi Bridge, PCI cards that accept wireless PC cards and external USB wireless NICs. The following are the component figures:

accecpoint.jpg

Figure 2: Access Point Figure 3: Adapters

wifi antena.jpg wifi bridge.jpg

Figure 4: Wi-Fi Antenna Figure 5: Wi-Fi Bridge

Figure 6: PCI cards that accepts wireless PC card Figure 7: External USB wireless NICs

How Wi-Fi network works?

Wi-Fi network uses the radio waves to communicate each other among devices. The basic concept of the Wi-Fi network is same as the walkie talkies. An access point to the internet connection can be installed through the Wi-Fi hotspot. This access point acts as base station. With this access point, an antenna is physically connected to conventional wired Ethernet network and serves as a bridge to the wireless network. A device encounters the hotspot when the Wi-Fi is enabled and the device can connect to that network wirelessly. Between the client systems, the Wi-Fi can also support communication and allowing the devices to communicate with one another during the peer-to-peer method.

A Wi-Fi 802.11b typically can transmit the maximum data rate up to 11Mbps with an approximation range of 150 feet. Beyond that distance, the signal fallback very slow up to 5.5 Mbps, 2Mbps and 1Mbps and this slower speed can move the signals as far as 1500 feet. The actual performance of the network depends upon the signal pattern and the number of obstacles in the area. To indicate the wireless within the area, an access point itself announces through broadcasting, a Service Set Identifier (SSID) approximately 10 times per second. The SSID indicates the name of the network. PCs that are within the range and has equipped with wireless network interface card can receive the SSID, associate with WLAN and request an IP address that will allow them to connect to the local network, surf the internet and view network folders [4].

Wi-Fi Network Topologies

Access Point (AP) in the Wi-Fi may vary greatly depending upon their cost but in some of the cases these AP gives selection for roaming where the wireless clients can switch from one AP to another. There are three kinds of network topologies.

AP (Access Point)-based topology (Infrastructure Mode)

Peer-to-Peer topology (Ad-hoc Mode)

Point-to-multipoint bridge topology.

AP-Based Topology:

Access Point (AP) is the wireless component through which the client can communicate. Access point is the device that contains standard IEEE 802.11 conformant MAC and PHY interface to the wireless medium and provides access to the distribution system for associated stations. Through an AP, BSA-RF (Basic Service access is the area of the radio frequency (RF)) coverage is provided. ESA (Extended Service Access) consists of two or more BSA. In order to allow the roaming, ESA cell consists of 10-15% overlap. The following figure shows the AP-based topology [9].

Figure 8: AP-Based topology

Peer-to-Peer Topology:

In this topology, the access point is not required. Within the cell, the client devices can communicate directly with one another. This topology is useful in setting up the wireless network very quickly and easily. The following figure shows the peer to peer method.

Figure 9: peer-to peer method

Point-to-multipoint bridge topology:

This type of topology is used in buildings from one to another building apart within the miles. This is required to connect a LAN in one building to a LANs in another building. A clear line of sight is achieved among buildings under these conditions. Based on the type of antenna and wireless bridge used the line-of-sight range varies and as well as in environmental conditions. The following figure shows the point to multipoint bridge topology

Figure 10: point-to-multipoint bridge topology

Access Point and Wireless Card are the two ways that can use for the networking.

Ad-hoc: In this method, the entire wireless cards are used from peer-to-peer network and there is no access point (AP).

Infrastructure: All wireless cards connect to the central access point that provides them connectivity with each other as well as wired network [1].

Wi-Fi Configurations

A Wi-Fi network is very simple and can be easily set up to the homes and offices that allow the network to share the files, printer and so on.

Figure 11: Wireless network set up

The public “Wi-Fi hot spots” are rapidly becoming common in airports, business, hotels, libraries and so on.

Wi-Fi Security

Security is one of the first disquiet of people deploying a wireless LAN, the 802.11 has addressed the issue through providing what is called WEP (Wired Equivalent Privacy). The main concerns of the users are that an intruder would not be able to access the network resources through similar wireless LAN equipment and be able to capture the wireless LAN traffic (eavesdropping).

There are two primary components which are required for Wi-Fi network security to be broken down.

Authentication

Privacy

There are two types of authentication is required: first is user authentication and second is server authentication.

Authentication means keeping the unauthorized users off from the network. In user authentication server, the username and password is required. This authentication has a risk as well as a solution in sending the data. The risk one is the data is send before the secure channel is established and level to passive eavesdropping by attackers. The solution for this is, before sending the username and password, encrypted channel is established. Secondly in server authentication, the digital certificate is used and within the client software the validation of the digital certificate occurs automatically.

Wireless Protected Access (WPA) is a standard based specification, interoperable security enhancement that strongly increase the level of data protection and for existing access control and future wireless LAN systems.

Wi-Fi Applications

Wi-Fi technology is simple and easy to access the network without the wire. At present, the Wi-Fi is most popular technology that has been used in the market. There are several applications through the Wi-Fi technology. It is used at homes, office, small businesses, large corporations and campuses, health care, wireless ISP (WISP) and travellers.

Advantages and Disadvantages of Wi-Fi

Advantages of Wi-Fi:

It allows the LANs to be set up without cabling and also it reduces the costs and expansion of the network.

Wi-Fi network support roaming such that a laptop can move from one access point to another.

Wi-Fi is global set of standards.

Mobility

Ease of installation

Reliability and Flexibility

Security

Use unlicensed part of radio spectrum

Disadvantages of Wi-Fi:

It can access to limited range.

Higher power consumption

The most common wireless encryption standard, Wired Equivalent Privacy (WEP) has been broken even if the correct configuration is set up.

Interference

Typically, Wi-Fi Access Point is set to default to an open (encryption-free) mode.

Conclusion:

In the past few years, the Wi-Fi technology is growing very rapidly in the rural development areas. In the rural areas, the technology has been helped the consumers in receiving the high speed internet service. All through urban environment the Wi-Fi “hot spots” are becoming more popular. When the Wi-Fi technology has brought up to the rural and urban areas the broadband internet access price has been drive down. According to the various industrial applications, the network connectivity for the industrial wireless solution provides that is cost effective and efficient. To ensure the reliability of wireless connectivity and safety of industrial operations, a hazardous area classification is necessary that provides the redundant links “radio”. Currently, there are several standard-based wireless technologies that are used for the industrial applications for the field sensors networking such as ISA100, WHART and ZigBee. Wi-Fi technology is simple and easy to deploy to the network. The IEEE 802.11 is the standard used for the Wi-Fi “hot spots”.

With appropriate security features, industrial hardware and industrial interface products, “Wi-Fi” technology has a certain association of commercial technology, based on the 802.11 technology and is becoming a solution for many industrial communications and networking.