Wimax vsWi-fi


Published on

Presented by Reshma M.R.

Wi-Fi, which stands for “Wireless Fidelity”, is a radio technology that networks computers so
they connect to each other and to the Internet without wires.

WiMAX, meaning Worldwide Interoperability for Microwave Access, is a
telecommunications technology that provides wireless transmission of data using a variety of
transmission modes, from point-to-point links to portable internet access

Published in: Technology, Business
  • Be the first to comment

Wimax vsWi-fi

  1. 1. WiMAX Versus Wi-Fi A Seminar Report Submitted by Reshma MR In partial fulfillment for the award of the degree Of BACHELOR OF TECHNOLOGY In COMPUTER SCIENCE AND ENGINEERING SCHOOL OF ENGINEERINGCOCHIN UNIVERSITY OF SCIENCE & TECHNOLOGY COCHIN-682022 August 2010
  2. 2. DIVISION OF COMPUTER ENGINEERING SCHOOL OF ENGINEERING COCHIN UNIVERSITY OF SCIENCE AND TECHNOLOGY COCHIN– 682022 CERTIFICATE Certified that this is a bonafied record of the Seminar work entitled “WIMAX versus Wi-Fi” done by RESHMA.M.Rof the VIIth semester, Computer Science and Engineering in the year 2010 in partialfulfillment of the requirements to the award of Degree of Bachelor of Technology inComputer Science Engineering of Cochin University of Science and Technology.Dr.David Peter Mr.Sudheep ElayidomHead of the department Seminar Guide
  3. 3. ACKNOWLEDGEMENTIt is with greatest pleasure and pride that I present this report before you. At this moment oftriumph, it would be unfair to neglect all those who helped me in the successful completion ofthis seminar. First of all, I would like to place myself at the feet of God Almighty for his everlastinglove and for the blessings & courage that he gave me, which made it possible to me to seethrough the turbulence and to set me in the right path.I would also like to thank our Head of the Department, Mr. David Peter S for all the help andguidance that she provided to me. I am grateful to my guide, Mr. Sudheep Elayidom.M , for his guidance and whole heartedsupport and very valued constructive criticism that has driven to complete the seminarsuccessfully.I would take this opportunity to thank my friends who were always a source of encouragement.
  4. 4. ABSTRACTWi-Fi, which stands for “Wireless Fidelity”, is a radio technology that networks computers sothey connect to each other and to the Internet without wires .Users can share documents andprojects, as well as an Internet connection among various computer stations, and easilyconnect to a broadband Internet connection while traveling. By using a Wi-Fi network,individuals can network desktop computers, laptops and PDAs and share networkedperipherals like servers and printers. A Wi-Fi network operates just like a wired network,without the restrictions imposed by wires. Not only does it enable users to move around bemobile at home and at work , it also provides easy connections to the Internet and businessnetworks while traveling .The technologies used in this field are one of the best in thewireless space . It is fairly easy to set up a Wi-Fi enabled network at home or a small office.WiMAX, meaning Worldwide Interoperability for Microwave Access, is atelecommunications technology that provides wireless transmission of data using a variety oftransmission modes, from point-to-point links to portable internet access [citation needed].The technology provides up to 75 Mbits/ symmetric broadband speed without the need forcables. The technology is based on the IEEE 802.16 standard (also called BroadbandWireless Access). The name “WiMAX” was created by the WiMAX Forum, which wasformed in June 2001 to promote conformity and interoperability of the standard. The forumdescribes WiMAX as a standards-based technology enabling the delivery of last mile wirelessbroadband access as an alternative to cable and DSL”.s
  5. 5. Table of ContentsChapter No. Title Page No. 1 Introduction 1 2 Wireless Networking 2 2.1 Wireless Standards 3 3 What is Wi-Fi 4 3.1 How Wi-Fi 6 3.2 Wi-Fi Technology Standards 9 3.3 Advantages of Wi-Fi 10 3.4 Disadvantage of Wi-Fi 11 4 What is WiMAX? 13 4.1 How WiMAX works 14 4.2 Backhaul 16 4.3 Types of WiMAX 17 4.4 Advantages of WiMAX 19 4.5 Disadvantages of WiMAX 19 5 WiMAX Versus Wi-Fi 20 5.1 Uses of Wi-Fi versus WiMAX 22 5.2 Capacity of Wi-Fi versus WiMAX 22 5.3 Technical difference of the two standards 23 6 Conclusion 26 7 References 27
  6. 6. LIST OF FIGURESFig no. FIGURES Page no: 1 Wi-Fi and WiMAX logo 1 2 Wireless network 2 3 802 Wireless standards 3 4 WLAN Standards 4 5 How Wi-Fi works 7 6 WMAN Standards 13 7 How WiMAX works 15 8 A WiMAX tower 16
  7. 7. List of TablesTab no. Tables Page no 1 IEEE 802.11 Radio Link Interface 10 2 Summary of 802.16 Radio Link 19 3 Mobile Standards Compared 24 4 Comparison WiMAX and Wi-Fi 25
  8. 8. Wi-MAX Versus Wi-Fi CHAPTER 1 INTRODUCTION WiMAX is not a technology, but rather a certification mark, or stamp of approval givento equipment that meets certain conformity and interoperability tests for the IEEE 802.16 familyof standards. A similar confusion surrounds the term Wi-Fi, which like WiMAX, is acertification mark for equipment based on a different set of IEEE standards from the 802.11working group for wireless local area networks (WLAN). Neither WiMAX, nor Wi-Fi is atechnology but their names have been adopted in popular usage to denote the technologiesbehind them. This is likely due to the difficulty of using terms like IEEE 802.16 in commonspeech and writing. Fig 1: Wi-Fi and WiMAX logo WiMAX and Wi-Fi are both wireless broadband technologies, but they differ in thetechnical execution. Wi-Fi was developed to be used for mobile computing devices, such aslaptops, in LANs, but is now increasingly used for more services, including Internet and VoIPphone access, gaming, and basic connectivity of consumer electronics such as televisions andDVD players, or digital cameras. On the other hand WiMAX was developed as a standards-based technology enabling the delivery of last mile wireless broadband access as an alternative tocable and DSLDivision of Computer Science, SOE CUSAT 1
  9. 9. Wi-MAX Versus Wi-Fi CHAPTER 2 WIRELESS NETWORKINGHow Internet can be made available in remote places of our county with cost effective manner?By using wireless networksImagine the possibility of an ambulance with high quality wireless connections to a hospital,vital information of injured patient can be send to hospital instantly from accident sport so thatthe hospital would be ready for treating the patient by the time he/she arrives there. The termwireless networking refers to technology that enables two or more computers to communicateusing standard network protocols but without network cable.Wireless networks recognize theradio waves and microwaves to maintain communication channel between computers FIG 2: Wireless Network between two computersDivision of Computer Science, SOE CUSAT 2
  10. 10. Wi-MAX Versus Wi-FiBasic type of wireless networks can be classified into  Ad hoc network (Peer to Peer): each device is equipped with wireless Cards and they can setup a network very quickly with out any infrastructure.  Infrastructure based network: The device communicate each other through a base station.2.1 Wireless StandardsIEEE 802 refers to a family of IEEE standards dealing with local area networks andmetropolitan area networks. More specifically, the IEEE 802 standards are restricted tonetworks carrying variable-size packets. (By contrast, in cell-based networks data is transmittedin short, uniformly sized units called cells. Isochronous networks, where data is transmitted as asteady stream of octets, or groups of octets, at regular time intervals, are also out of the scope ofthis standard.) The number 802 was simply the next free number IEEE could assign, through”802” is sometimes associated with the date the first meeting was held – February 1980 Fig 3: 802 wireless standardsDivision of Computer Science, SOE CUSAT 3
  11. 11. Wi-MAX Versus Wi-Fi CHAPTER 3 What is Wi-Fi?Wi-Fi is a trademark of the Wi-Fi Alliance that manufacturers may use to brand certifiedproducts that belong to a class of wireless local area network (WLAN) devices based on theIEEE 802.11 standards, which is by far the most widespread WLAN class today. Because of theclose relationship with its underlying standard, the term Wi-Fi is often used as a synonym forIEEE 802.11 technologyWi-Fi is for Wireless Fidelity, essentially a set of standards for transmitting data over a wirelessnetwork. Wi-Fi allows you to connect to the net at broadband speeds without cables, as long asyou have the right equipment and, in most cases, a regular internet service provider and a Wi-Fiaccount. Fig 4: WLAN standardDivision of Computer Science, SOE CUSAT 4
  12. 12. Wi-MAX Versus Wi-FiUSES: 1. Internet Access A Wi-Fi enabled device such as a personal computer, video game console, mobile phone,MP3 player or personal digital assistant can connect to the Internet when within range of awireless network connected to the Internet. The coverage of one or more (interconnected) accesspoints — called hotspots — can comprise an area as small as a few rooms or as large as manysquare miles. Coverage in the larger area may depend on a group of access points withoverlapping coverage.In addition to private use in homes and offices, Wi-Fi can provide public access at Wi-Fihotspots provided either free-of-charge or to subscribers to various commercial services.Organizations and businesses - such as those running airports, hotels and restaurants - oftenprovide free-use hotspots to attract or assist clients.In internet access we have 1.a City-wide Wi-Fi In the early 2000s, many cities around the world announced plans for city- wide Wi-Fi networks. This proved to be much more difficult than their promoters initially envisioned with the result that most of these projects were either cancelled or placed on indefinite hold. A few were successful, for example in 2005, Sunnyvale, California became the first city in the United States to offer city-wide free Wi-FiDivision of Computer Science, SOE CUSAT 5
  13. 13. Wi-MAX Versus Wi-Fi 1.b Campus-wide Wi-Fi Carnegie Mellon University built the first wireless Internet network in theworld at their Pittsburgh campus in 1994, long before Wi-Fi branding originated in 1999. Mostcampuses now have wireless Internet. 2. Direct Computer-to-Computer Communication Wi-Fi also allows communications directly from one computer to another without the involvement of an access point. This is called the ad-hoc mode of Wi-Fi transmission. 3. Future Directions As of 2010 Wi-Fi technology has spread widely within business and industrial sites. In business environments, just like other environments, increasing the number of Wi-Fi access points provides network redundancy, support for fast roaming and increased overall network-capacity by using more channels or by defining smaller cells. Wi-Fi enables wireless voice-applications3.1 How Wi-Fi works?Wi-Fi uses one or more Wireless Access Points (WAP) (can be compared to cell phone towers)and clients (WiFi Adapters) (comparable to cell phones) to transfer data by the use of radiowaves. These Access points serve as base station for various wi-fi enabled equipments.Division of Computer Science, SOE CUSAT 6
  14. 14. Wi-MAX Versus Wi-FiThe access point broadcasts it’s SSID (The network name) and clients can identify it and decideto connect. If two or more access point uses same SSID, the client will automatically connect tothe access point that has better signal strength.The electronics on the receiver’s end are called WiFi adapters and it can be either in-built to thedevice itself or can be in the form of an external device like a USB stick.Wi-Fi networking can transfer data at a rate ranging from 2Mbps – 108 Mbps and for a distancefrom several meters to several hundred meters. The signal strength depends on the distance fromaccess points and the type of Wi-Fi technology in use.Figure below shows how Wi-Fi works. The description of the numbers shown in the figure helpsto understand the working of Wi-Fi. Fig 5: How does Wi-Fi worksDivision of Computer Science, SOE CUSAT 7
  15. 15. Wi-MAX Versus Wi-Fi1: Wi-fi uses antennas around which wi-fi "hotspots" are created. The hotspots are outletsequipped to receive the radiowaves that power wireless networking. Until recently, wi-fi hasbeen confined to more than 10,000 hot-spots in cafes, bars and airport lounges. But variousprojects are under way to set up city-wide zones, where a series of antennas are installed in thestreets, on lampposts or street signs. The hotspots around them together create a much wider areaof coverage. Norwich has a mesh network which links each lamppost antenna to the nextcreating a seamless wi-fi hotspot around the centre of the city.2: The source internet connection is provided by a PC or server to which the antennas areconnected either wirelessly or via a cable.3: Some mobile phones and personal digital assistants (PDA) now have Wi-Fi chips installed.With mobile phones, this means conventional networks can be bypassed and inexpensive long-distance calls made over the web (using Voice over Internet Protocol, VoIP).4: Many laptops and handheld computers now come with built-in wi-fi connectivity; it is alsopossible to add wi-fi to your computer with a special card that plugs into a port on your laptop.Division of Computer Science, SOE CUSAT 8
  16. 16. Wi-MAX Versus Wi-Fi3.2 Wi-Fi Technology Standards  IEEE 802.11 Standards Wi-Fi The first version of Wi-Fi standard 802.11 uses 2.4GHz spectrum to transfer data. Theoperating speeds were around 1-2Mbps. This version was released in 1997.  IEEE 802.11a (Wi-Fi a) Released in 1999, this version of Wi-Fi uses 5GHz frequency spectrum and are capableof providing 10Mbps speed.  IEEE 802.11b (Wi-Fi b) This was the modified format to tackle the issues of 802.11a version, where multipleaccess points were required for stable reception. The major change was that this version uses2.4GHz frequency spectrum. 802.11b version works at a speed of 11Mbps and was widelyaccepted at the time of release.  IEEE 802.11g (Wi-Fi g) The most widely accepted Wi-Fi networking format of modern times. Wi-Fi g can deliverspeeds up to 54Mbps and can support many clients. This version works on 2.4GHz spectrum.This version was released in 2003.  IEEE 802.11n (Wi-Fi n)Division of Computer Science, SOE CUSAT 9
  17. 17. Wi-MAX Versus Wi-Fi The newest version, currently in draft can deliver speeds up to 108Mbps and has a signalrange of several hundred meters. This technology uses multiple input multiple output pipeliningand hence can use multiple antennas for better signal strength. Standard Maximum bit Channels Frequency Radio rate provided band techniques 802.11 2 Mbps 3 2.4 GHz FHSS or DSSS 802.11 b 11 Mbps 3 2.4 GHz DSSS 802.11 a 54 12 5 GHz OFDM 802.11 g 54 3 2.4 GHz OFDM Table 1: IEEE 802.11 Radio Link Interfaces3.3 Advantages of Wi-Fi • No Wires Required – Wi-Fi technology allows you to deploy networks without the hassle of wiring up your computers. Since Wi-Fi does not use wires, you can easily set up wireless networks even outdoors.Division of Computer Science, SOE CUSAT 10
  18. 18. Wi-MAX Versus Wi-Fi • Wi-Fi Chipsets are Cheap – Wi-Fi adapters are now built-in with laptops; hence you don’t need to add any extra device to receive Wi-Fi signals. • New Wi-Fi Devices – Many new devices (Camera / Cell phones / Personal Media Players / Media Storage Devices …) support Wi-Fi technology. You can easily transfer files from these devices without any wires. Some of the newer devices even provide direct internet uploading from the device itself. • Backward Compatibility – Wi-Fi versions working on same operating spectrum are backward compatible. Hence if you have an old Wi-Fi device, it can work on your newest Wi-Fi access point. • Data Encryption – Wi-Fi supports different types of advanced encryption technologies to securely encrypt your data. This means, you can use wifi for transferring confidential data on a secured network. • Wifi Hotspots – Businesses can provide Wi-Fi hotspots (Public Wi-Fi area) to increase the customer base. Many universities, Airports and retail markets started providing public WiFi services.3.4 Disadvantages of Wi-Fi • Signal Strength Limitation – As wifi uses radio waves, the signal strength is affected by the presence of obstacles. Hence wifi works better on outdoors than indoors. • Data Transfer Limit – According to latest Wi-Fi n draft, this technology can seamlessly deliver speeds upto 108Mbps, but we already have better technology (Gigabit LAN) thatDivision of Computer Science, SOE CUSAT 11
  19. 19. Wi-MAX Versus Wi-Fi can deliver speeds up to 1000 Mbps. Hence Wi-Fi technology in present state are not suitable for fast connectivity needs like network gaming. • Uses Shared Frequency Spectrum – The operating frequency of 2.4GHz is used by Bluetooth devices, Microwave ovens, Cordless Phones and many other home appliances. Hence there is a chance of interference or network crowding for the Wi-Fi signals, which can adversely affect the quality of signal. • Un-Secured WAP(Wireless Access Point) can result in malicious usage. Even though many routers / access points comes with security features, they are seldom used. The result is that anyone with a Wi-Fi adapter with in the range can use your connection without your knowledge.Division of Computer Science, SOE CUSAT 12
  20. 20. Wi-MAX Versus Wi-Fi CHAPTER 4 What is WiMAX?WiMAX is a digital wireless data communication system that can deliver high-speed broadbandservices up to a large distance of 50KMs.The name WiMAX was created by WiMAX forum, theconsortium promoting this standard. The term WiMAX is derived from the phrase WorldwideInteroperability for Microwave Access.The WiMAX system was designed to popularize broadband access the way cell phones havedone to our telephone communication system. WiMAX may replace the old form of broadbandaccess through landlines, DSL and cable in future.The WiMAX system can be considered as an efficient alternative to Wi-Fi, where the un-avoidable limitation was the distance of coverage. WiMAX solves this problem by using higherfrequency range to deliver more data to a larger distance. Fig 6: WMAN standardDivision of Computer Science, SOE CUSAT 13
  21. 21. Wi-MAX Versus Wi-FiUSES:The bandwidth and range of WiMAX make it suitable for the following potential applications: • Providing portable mobile broadband connectivity across cities and countries through a variety of devices. • Providing a wireless alternative to cable and DSL for "last mile" broadband access. • Providing data, telecommunications (VoIP) and IPTV services (triple play). • Providing a source of Internet connectivity as part of a business continuity plan. • Providing a network to facilitate machine to machine communications, such as for Smart Metering4.1 How WiMAX Works?WiMAX, just like Wi-Fi uses radio waves to transfer data. The important difference is thatWiMAX uses two spectrums of frequencies to provide two kinds of wireless broadband accessservices. (Mobile WiMAX & Fixed WiMAX)The WiMAX system has two parts; one is the WiMAX tower (similar to a cell phone tower) anda receiver. The receiver can be of two types depending on the device. It can be an embeddeddevice just like our wi-Fi receivers or it can be advanced hardware equipment with dedicatedantennae.The WiMAX tower connects to internet through regular mediums of connectivity like fibre opticcable or T1 lines. It can also connect with other WiMAX towers using radio link.Division of Computer Science, SOE CUSAT 14
  22. 22. Wi-MAX Versus Wi-FiThis additional line-of-sight connectivity is the biggest advantage of WiMAX. Technically, thisis called the backhaul system. Thus by installing multiple towers, WiMAX can easily providebroadband access to large number of people. Fig 7: How WiMAX worksDivision of Computer Science, SOE CUSAT 15
  23. 23. Wi-MAX Versus Wi-Fi4.2 BACKHAULBackhaul is actually a connection system from the Access Point (AP) back to the provider andto the connection from the provider to the network. A backhaul can set out any technology andmedia provided; it connects the system to the backbone. In most of the WiMAX deploymentscircumstances, it is also possible to connect several base stations with one another by use ofhigh speed backhaul microware links. This would also allow for roaming by a WiMAXsubscriber from one base station coverage area to another, similar to roaming enabled bycellular phone. Fig 8: A WiMAX TOWERDivision of Computer Science, SOE CUSAT 16
  24. 24. Wi-MAX Versus Wi-Fi4.3 Types of WiMAXWiMAX delivers broadband access in two ways depending on the operational frequencies. • Fixed WiMAX • Mobile WiMAX o Fixed WiMAX802.16-2004 is also known as 802.16d, which refers to the working party that has developed thatstandard. It is sometimes referred to as "Fixed WiMAX," since it has no support for mobility.In this form, WiMAX tower works more like an efficient & powerful Wi-Fi access point. Thefrequency range of operation is 2GHz – 11GHz, almost similar to Wi-Fi frequencies.In this mode of operation, the data transfer occurs between WiMAX tower and the internalmobile receivers. As the frequency of operation is low, there is a limitation in area of coverage.According to theory, this type of WiMAX can only deliver up to 6-7 KMs.The same effect can be analogized to cell phone tower system. That is the same reason, why weneed more number of towers for wide area coverage. o Mobile WiMAX802.16e-2005, often abbreviated to 802.16e, is an amendment to 802.16-2004. It introducedsupport for mobility, among other things and is therefore also known as "Mobile WiMAX".Division of Computer Science, SOE CUSAT 17
  25. 25. Wi-MAX Versus Wi-Fi In this form, the receiver requires dedicated antennae properly installed in the line-of-sight ofWiMAX tower. These types of connections are stronger and stable as it uses 66GHz frequencyspectrum to carry more data. This mode of operation can deliver broadband services to about50KM radius. Table 2: Summary of 802.16 Radio LinkDivision of Computer Science, SOE CUSAT 18
  26. 26. Wi-MAX Versus Wi-Fi4.4 Advantages of WiMAX • Large Area of Coverage: As WiMAX can deliver high-speed internet to large distance, it is very well suited to provide broadband access to remote areas of the world. • Scalability: As earlier mentioned, by using backhaul feature of WiMAX, you can set up large number of WiMAX towers in matter of days as opposed to wiring that requires proper planning and heavy labor. • In Built QoS: Quality of Service mechanisms in WiMAX allows mission-critical services to run smoothly even if there is lack of resources. This way, mission critical services are allowed to run at full priority when everything is busy. • Multi-User Connectivity: A single WiMAX tower can connect to 100 client receivers. These clients can of different modes of operation4.5 Disadvantage of WiMAX • Specialized Equipment Required: For utilizing full functionality of WiMAX, you need specialized hardware with dedicated antennae. • Limited Date Rate: When compared to other modes of broadband connectivity, for example, fibre optic cables and satellite internet, WiMAX is still slow. • Bandwidth Shared Among Users: WiMAX’s another drawback is that it distributes the bandwidth among users. This means, you will experience slow down when there are more uses in the base. • Speed Decrease over Large Distance: Because of bit rate errors happening at large distance, WiMAX system is forced to use lower bit rates at these distances. This means less data transfer rate.Division of Computer Science, SOE CUSAT 19
  27. 27. Wi-MAX Versus Wi-Fi • Interference May Affect Connectivity: As the WiMAX uses radio waves, it is susceptible to interference caused by other equipments. • Rain can affect Connectivity: As fixed WiMAX requires line-of-sight radio link, heavy rain can disrupt the entire link.Division of Computer Science, SOE CUSAT 20
  28. 28. Wi-MAX Versus Wi-Fi CHAPTER 5 WiMAX versus Wi-FiComparing WiMAX to Wi-Fi is akin to comparing apples to oranges. Initially it’s easy to seewhy the comparison would exist, as most people think WiMAX is merely a more robust versionof Wi-Fi. Indeed they are both wireless broadband technologies, but they differ in the technicalexecution and ultimately their business case is very different. In addition to the technicaldifferences that exist, the marketplace difference is that equipment is more or less non-existentfor WiMAX and certainly not geared towards a residential environment with very high pricing tobe expected. It will take at least 2 years to see equipment of mass market uptake pricing.WiMAX will not be commercially available until the second half of 2005, and even then at avery controlled level. This is primarily due to standardization issues. In fact, it won’t be until2006 that a robust production and implementation will happen due to the ramp-up period formanufacturers. This is certainly one challenge to the widespread adoption of WiMAX.Additionally, WiMAX will have issues of pricing, and will remain far more expensive than Wi-Fi. WiMAX will be primarily adopted by businesses to replace or displace DSL, and offices thatwant to cover a lot of territory without entering the world of endless repeaters that are necessarywith the 802.11 technologies. It will take some time (2 years) for WiMAX to significantly reduceits price-point for residential uptake. WiMAX will not displace WiFi in the home because WiFiis advancing in terms of speed and technology. Each year brings a new variant to the 802.11 areawith various improvements.Additionally, for commercial deployment, frequency allocation will be an issue. With the threedominant communications players controlling the best frequencies, it will be hard to get the typeof traction needed with the remaining companies operating in the frequencies available. WiMAXwill become extremely robust and displace WiFi as the deployment of choice for commercialdeployments, but that won’t even begin until the end of 2006. Based upon the number of publichotspots already deployed, WiMAX will not be chosen to replace those as they are up andDivision of Computer Science, SOE CUSAT 21
  29. 29. Wi-MAX Versus Wi-Firunning adequately and personnel involved understand how to work with the technology. Thebusiness case does not exist at the hotspot level. Where it may exist is for wider free usedeployments such as city deployments (free ones) and other government sponsored or carriersponsored (with ultra inexpensive pricing for consumers) deployments. If this happens then itsnot only WiFi that will be displaced, but cable and DSL will also lose a percentage of theirsubscriber base. What will cause the displacement is the consumer’s proven desire for a bundledpackage.5.1 Uses of Wi-Fi vs. the uses of WiMAX Wi-Fi is mostly used to provide a Wi-Fi enabled device such as a computer, cell phone orPDA an Internet/LAN connection when in proximity of an access point. Wi-Fi can also be usedto create a mesh network. Wi-Fi also allows connectivity in peer-to-peer mode, which enablesdevices to connect directly with each other. WiMAX on the other hand with its higher bandwidth and longer reach is planned to beused for connecting Wi-Fi hotspots with each other and to other parts of the Internet, providing awireless alternative to cable and DSL for last mile (last km) broadband access, providing high-speed mobile data and telecommunications services (4G).5.2 Capacity of Wi-Fi vs. WiMAX Both the Wi-Fi and the WiMAX connectivity are dependent on the distance of twoconnection points (antennas). Keeping this in mind we can see that when using Wi-Fi with theIEEE 802.11g standard, which is the most common standard used on today’s equipment, the datarate is around 54 Mbit/s and the range indoors are around 30 meters. This range and data rate ischanged with the conditions of the area used and the line of sight of devices used.Division of Computer Science, SOE CUSAT 22
  30. 30. Wi-MAX Versus Wi-Fi WiMAX will deliver 70 Mbit/s, 112 kilometers in theory. But these numbers will changeaccording to conditions, expected values are 10Mbit/s in a 2 KM area.5.3 Technical differences of the two standards5.3.1 Media Access Controller (MAC) Layer In Wi-Fi MAC uses contention access — all subscriber stations that wish to pass datathrough a wireless access point (AP) are competing for the APs attention on a random interruptbasis. This can cause subscriber stations distant from the AP to be repeatedly interrupted bycloser stations, greatly reducing their throughput. This makes services such as Voice over IP(VoIP) or IPTV, which depend on an essentially constant Quality of Service (QoS) depending ondata rate and interruptibility, difficult to maintain for more than a few simultaneous users. In contrast, the 802.16 MAC uses a scheduling algorithm for which the subscriber stationneed compete once (for initial entry into the network). After that it is allocated an access slot bythe base station. The time slot can enlarge and contract, but remains assigned to the subscriberstation which means that other subscribers cannot use it. The 802.16 scheduling algorithm isstable under overload and over-subscription (unlike 802.11). It can also be more bandwidthefficient. The scheduling algorithm also allows the base station to control QoS parameters bybalancing the time-slot assignments among the application needs of the subscriber stations.5.3.2 Physical layer In Wi-Fi except for 802.11a, which operates at 5 GHz, Wi-Fi uses the spectrum near 2.4GHz, which is standardized and unlicensed by international agreement, although the exactfrequency allocations vary slightly in different parts of the world, as does maximum permittedpower. However, channel numbers are standardized by frequency throughout the world, soauthorized frequencies can be identified by channel numbers. The frequencies for 802.11 b/gspan 2.400 GHz to 2.487 GHz. Each channel is 22 MHz wide yet there is a 5 MHz step to thenext higher channel. The maximum number of available channels for Wi-Fi enabled devices is13 for Europe, 11 for North America and 14 for Japan.Division of Computer Science, SOE CUSAT 23
  31. 31. Wi-MAX Versus Wi-Fi Whereas in WiMAX, the original WiMAX standard (IEEE 802.16) specified WiMAX forthe 10 to 66 GHz range. 802.16a, updated in 2004 to 802.16-2004 (also known as 802.16d),added specification for the 2 to 11 GHz range. 802.16d (also known as "fixed WiMAX") wasupdated to 802.16e in 2005 (known as "mobile WiMAX"). and uses scalable orthogonalfrequency-division multiplexing (OFDM) as opposed to the OFDM version with 256 sub-carriersused in 802.16d. More advanced versions including 802.16e also bring Multiple AntennaSupport through Multiple-input, multiple-output communications. This brings potential benefitsin terms of coverage, self installation, power consumption, frequency re-use and bandwidthefficiency. 802.16e also adds a capability for full mobility support. The WiMAX certificationallows vendors with 802.16d products to sell their equipment as WiMAX certified, thus ensuringa level of interoperability with other certified products, as long as they fit the same profile. Most interest will probably be in the 802.16d and .16e standards, since the lowerfrequencies suffer less from inherent signal attenuation and therefore give improved range andin-building penetration. Already today, a number of networks throughout the World are incommercial operation using certified WiMAX equipment compliant with the 802.16d standard.5.3.3 Network layer Both standards are designed to be used with the first and the second layers of the OSImodel. Both the standards can be used with a variety of different network layers, including IP. Table 3: Mobile Standards ComparedDivision of Computer Science, SOE CUSAT 24
  32. 32. Wi-MAX Versus Wi-FiIn general we can say, even though both WiMAX and Wi-Fi works on radio waves, there aredifferences in their operations and functionalities. WiMAX Wi-Fi (802.16) (802.11)Range long distance system, high- short-range system, speed broadband access to broadband access to several several KMs hundred feetData Rate 70Mbps 54MbpsScalability highly scalable Not scalableLocal Network cannot use it for your own work for private networks private networkSpectrum Licensing requires spectrum licensing does not require such a license Table 4: the comparison of WiMAX and Wi-FiDivision of Computer Science, SOE CUSAT 25
  33. 33. Wi-MAX Versus Wi-Fi CHAPTER 6 ConclusionEven though WiFi technology has many disadvantages, properly configured WAPs will giveyou the best wireless connectivity you can get. Latest developments show that WiFi would beembedded in to most of the consumer devices, thus enabling us to wirelessly interact and thereby improve the productivity and entertainment experience.As WiMAX delivers high-speed internet through wireless medium, the cost of implementingbroadband access to remote parts of world are very low. Because of the same reason, we believeWiMAX have huge potential to become the world’s popular broadband access method in nearfuture.Wi-Fi and WiMAX are complementary. WiMAX network operators typically provide a WiMAXSubscriber Unit which connects to the metropolitan WiMAX network and provides Wi-Fi withinthe home or business for local devices (e.g., Laptops, Wi-Fi Handsets, smart phones ) forconnectivity. This enables the user to place the WiMAX Subscriber Unit in the best receptionarea (such as a window), and still be able to use the WiMAX network from any place withintheir residence.Division of Computer Science, SOE CUSAT 26
  34. 34. Wi-MAX Versus Wi-Fi CHAPTER 7 REFERENCES  Stallings, William, Data and Computer Communications, Pearson-Prentice Hall, 7th Ed., USA, 2004.  http://en.wikipedia.org/wiki/Wimax  http://en.wikipedia.org/wiki/Wifi  http://www.voip-news.com/news/features/wifi-vs-wimax-050806/  http://www.mobilein.com/WiFi_vs_WiMax.htm  http://en.wikipedia.org/wiki/IEEE_802.11  http://en.wikipedia.org/wiki/IEEE_802.16  http://en.wikipedia.org/wiki/OSI_model  http://changelog.ca/topic/WiMax  http://www.cisco.com/en/US/netsol/ns341/ns396/ns177/networking_solutions_white_pap er0900aecd801aa448.shtml  http://www.tutorialsweb.com/wimax/wimax.htmDivision of Computer Science, SOE CUSAT 27