Wi-max

WiMAX Author Balapure Bhushan R. Desle Vivek K. Gadhe Sandip D.

Abstract – The IEEE 802.16 standard (now called WiMAX) has been proposed to provide last-mile connectivity to fixed locations by radio links. Despite this original objective, we study in this paper the functional parts of a WiMAX system and its basic operation and how WiMAX can use base stations to provide high speed data connections that can be used for voice, data and video services to distances of over 30 km. We find that seamless connection handoff can be achieved within the 802.16 standard by applying some of the existing functionalities defined for the terminal initialization process. WiMAX protocols are designed to allow for point to point (PTP), point to multipoint (PMP) and mesh networks. In WiMAX expensive equipment are used as various versions of smart antennas, OFDM and sometimes mesh to provide often effective alternatives to wired communications.

I. INTRODUCTION WiMAX is short for Worldwide Interoperability for Microwave Access, and it also goes by the IEEE name 802.16. WiMAX has the potential to do to broadband Internet access what cell phones have done to phone access. In the same way that many people have given up their "land lines" in favor of cell phones, WiMAX could replace cable and DSL services, providing universal Internet access just about anywhere you go. WiMAX will also be as painless as Wi-Fi -- turning your computer on will automatically connect you to the closest available WiMAX antenna. The original WiMAX system was designed to operate at 1066 GHz and it had to change to offer broadband wireless access (BWA) in the 2-11 GHz frequency range. To do this, the WiMAX standard includes variants (profiles) that use different combinations of radio channel types (single carrier –vsmulticarrier), modulation types, channel coding types to provide fixed, nomadic or portable services. WiMAX can provide multiple types of services to the same user with different QoS (Quality of Service) levels. For example, it is possible to install a single WiMAX transceiver in an office building and provide real time telephone services and best effort Internet browsing services on the same WiMAX connection. To do this, WiMAX was designed to mix contention based (competitive access) and contention free (polled access) to provide services which have different quality of service (QoS) levels.

Goals of WiMAX The goal of WiMAX is to provide high-speed Internet access in a coverage range several kilometers in radius. In theory,

WiMAX provides for speeds around 70 Mbps with a range of 50 kilometers. The WiMAX standard has the advantage of allowing wireless connections between a base transceiver station (BTS) and thousands of subscribers without requiring that they be in a direct line of sight (LOS) with that station. This technology is called NLOS for non-line-of-sight. In reality, WiMAX can only bypass small obstructions like trees or a house and cannot cross hills or large buildings. When obstructions are present, actual throughput might be under 20 Mbps.

Operating principle of WiMAX At the heart of WiMAX technology is the base transceiver station, a central antenna which communicates with subscribers' antennas. The term point-multipoint link is used for WiMAX's method of communication.

The revisions of the IEEE 802.16 standard fall into two categories:

Fixed WiMAX, also called IEEE 802.16-2004, provides for a fixed-line connection with an antenna mounted on a rooftop, like a TV antenna. Fixed WiMAX operates in the 2.5 GHz and 3.5 GHz frequency bands, which require a license, as well as the license-free 5.8 GHz band.

Mobile WiMAX, also called IEEE 802.16e, allows mobile client machines to be connected to the Internet. Mobile WiMAX opens the doors to mobile phone use over IP, and even high-speed mobile services. TABLE 1 Standard Fixed WiMAX (802.16-2004) Mobile WiMAX (802.16e)

Frequency 2-11 GHz (3.5 GHz in Europe) 2-6 GHz

Speed

Range

75 Mbps

10 km

30 Mbps

3.5 km

II. HOW WIMAX WORKS In practical terms, WiMAX would operate similar to Wi-Fi but at higher speeds, over greater distances and for a greater

number of users. WiMAX could potentially erase the suburban and rural blackout areas that currently have no broadband Internet access because phone and cable companies have not yet run the necessary wires to those remote locations. A WiMAX system consists of two parts: A WiMAX tower, similar in concept to a cell-phone tower - A single WiMAX tower can provide coverage to a very large area -- as big as 3,000 square miles (~8,000 square km). A WiMAX receiver - The receiver and antenna could be a small box or PCMCIA card, or they could be built into a laptop the way Wi-Fi access is today. A WiMAX tower station can connect directly to the Internet using a high-bandwidth, wired connection (for example, a T3 line). It can also connect to another WiMAX tower using a line-of-sight, microwave link. This connection to a second tower (often referred to as a backhaul), along with the ability of a single tower to cover up to 3,000 square miles, is what allows WiMAX to provide coverage to remote rural areas.

Wi-Fi-style access will be limited to a 4-to-6 mile radius (perhaps 25 square miles or 65 square km of coverage, which is similar in range to a cell-phone zone). Through the stronger line-of-sight antennas, the WiMAX transmitting station would send data to WiMAX-enabled computers or routers set up within the transmitter's 30-mile radius (2,800 square miles or 9,300 square km of coverage). This is what allows WiMAX to achieve its maximum range. III. PROTOCOLS FOR CONNECTION HANDOFF Handoff Objective and Mobility Management:As the quality of an established radio link between a subscriber station (SS) (or terminal) and its BS deteriorates due to mobility, the objective of handing off the connection to a neighboring BS is to maintain the IP connectivity between the SS and the corresponding host. A major goal is to minimize packet loss and delay induced by the handoff process. Since the 802.16d standard defines only the physical (PHY) and MAC layers, without loss of generality, suppose that the network under study employs the hierarchical mobile IP (HMIP) algorithm [GJP02] for micro-mobility management. (Similar observations apply to other mobility management algorithms such as [CGK02] and [RVS02].) Using the common terminology for mobile networks, Figure 1 shows the architecture of the HMIP for the 802.16 network under consideration. Specifically, one router is designated the Primary Foreign Agent (PFA) and serves as the “anchor point” for each SS (or connection). That is data from and to a given SS always goes through the corresponding PFA. In addition, the PFA also keeps track of the operational parameters for the 802.16d connections associated with the SS. As shown in the figure, the communication path consists of multiple IP tunnels and packets are forwarded by tunneling.

Figure 2. How WiMAX Works

What this points out is that WiMAX actually can provide two forms of wireless service: There is the non-line-of-sight, Wi-Fi sort of service, where a small antenna on your computer connects to the tower. In this mode, WiMAX uses a lower frequency range -- 2 GHz to 11 GHz (similar to Wi-Fi). Lower-wavelength transmissions are not as easily disrupted by physical obstructions -- they are better able to diffract, or bend, around obstacles. There is line-of-sight service, where a fixed dish antenna points straight at the WiMAX tower from a rooftop or pole. The line-of-sight connection is stronger and more stable, so it's able to send a lot of data with fewer errors. Line-of-sight transmissions use higher frequencies, with ranges reaching a possible 66 GHz. At higher frequencies, there is less interference and lots more bandwidth.

Figure 6. Hierarchical Mobile IP for 802.16d Network

IV. WIMAX SYSTEM TYPES

some of the different types of uses that WiMax networks can provide. That is: 1) Point to Point (PTP) 2) Point to Multipoint (PTMP) This diagram shows that WiMax systems can be used for point-to-point links, residential broadband or high-speed business connections. This example shows that the point to point (PTP) connection may be independent from all other systems or networks. The point to multipoint (PTMP) system allows a radio system to provide services to multiple users. WiMax systems can also be setup as mesh networks allowing the WiMax system to forward packets between base stations and subscribers without having to install communication lines between base stations.

Figure 3. WiMAX system types

V. WIMAX STANDARDS EVOLUTION 802.16 broadband wireless systems have evolved with different standard over time. This diagram shows that the original 802.16 specification defined fixed broadband wireless service that operates in the 10-66 GHz frequency band. To provide wireless broadband service in lower frequency range, the 802.16A specification was created that operates in the 2-11 GHz frequency band. To provide both fixed and mobile service, the 802.16E specification was developed.

Figure 4. WiMAX standards evolution

WiMAX Standard Differences:This figure shows a comparison between the original Fixed WiMAX standard and the WiMAX standard that can be used for fixed, mobile and portable. This table shows that the original 802.16 standard was released in 2004 and it was only capable of providing fixed wireless data services. It used OFDM modulation and could be deployed in both TDD or FDD formats. The 802.16e standard was released in 2005 (now merged into the original 802.16 standard) was designed for fixed, mobile and portable operation. It used OFDMA modulation with TDD and optionally FDD duplexing capability.

Figure 5. WiMAX standards difference

WiMAX Radio Channel Types:This figure shows that WiMAX radio channels can be single carrier or multiple carriers. This diagram shows that the bandwidth of WiMAX radio channels can vary from 1.25 MHz to 28 MHz in steps of 1.75 MHz. This example also shows that a WiMAX system that is using multicarrier OFDMA and how some of the subcarriers have been assigned to a specific user.

Figure 7. WiMAX Radio Channel Types

WiMAX has the advantage of not being – at least until Intel has a long distance Centrino – a consumer technology. Although this has kept its profile lower than Wi-Fi’s, it has not suffered from the over-hype and its development is freer of vendor politics and posturing than its short distance cousin’s.

VI. WiMAX OVER OTHER TECHNOLOGIES Wi-Fi:The WiMAX Forum is keen to present 802.16 as complementary to the local area IEEE standard, 802.11 or WiFi. In many ways, this is right—802.16a, as we have seen, provides a low cost way to backhaul Wi-Fi hotspots and WLAN points in businesses and homes, and as uptake of Wi-Fi increases, the requirement for this backhaul will grow too. But there is conflict too. WiMAX makes redundant the efforts of Wi-Fi specialists to extend the reach of their favourite technology and also places 802.11 into a far smaller role than its supporters have, often unrealistically, carved out for it. This is the opportunity for wireless technologies finally to grow up and offer the speed, multimedia support and ubiquity that WiFi can never deliver. The newer standard holds all the real power. By providing a backbone for hotspots, based on standards rather than the various proprietary WLAN expansion technologies out there, it Makes the idea of a ubiquitous wireless network to rival cellular far more realistic than it ever was with Wi-Fi alone, despite the claims of the enthusiasts. The equipment makers are eyeing it keenly – amid all the doubts about the sustainability of the hotspot boom, anything that offers them a new product line plus helps to preserve the interest in Wi-Fi is to be welcomed. 802.16 is a highly complex standard which contains, from day one, many of the features that are being retrofitted, with various degrees of clumsiness and baggage, into Wi-Fi, which was originally conceived to be very simple and is now taking Wi-Fi:

WiMAX

802.11

802.16

2Mbps

54Mbps

100Mbps

Covera ge

Several miles

300 feet

50 miles

Airwav e

Licensed

3G Max speed

Unlicensed

Either

Range, Advant ages Disadv antages

Fi 802.20: 16Mbps Several miles Licensed Speed,

mobility

Speed, price

Speed, range

Slow,

Short

Interferenc

Expensive

Mobile-

range

e issues?

mobility

High price

on a burden of responsibility beyond its technological reach.

Cellular Technologies:WiMAX is a serious threat to 3G because of its broadband capabilities, distance capabilities and ability to support voice effectively with full QoS. This makes it an alternative to cellular in a way that Wi-Fi can never be, so that while operators are integrating Wi-Fi into their offerings with some alacrity, looking to control both the licensed spectrum and the unlicensed hotspots, they will have more problems accommodating WiMAX. But as with Wi-Fi, it will be better for them to cannibalize their own networks than let independents do it for them, especially as economics and performance demands force them to incorporate IP into their systems. Handset makers such as Nokia will be banking on this as they develop smart phones that support WiMAX as well as 3G. Relationship With Other Wireless Technologies:TABLE 2

BWA alternatives to WiMAX:Not everyone is taking the WiMAX pledge though. Flarion is the leader among OFDM-based vendors that are backing the metro area mobile wireless standard, 802.20 or Mobile-Fi, instead. IPWireless supports neither IEEE approach, but is still pushing its own mobile broadband technology, which is based on an IP packet data implementation of the UMTS 3G standard, operating at over 2.5 miles in urban areas at 16Mbps in 5MHz and 10GMz channels. This technology is less powerful or long distance than WiMAX, though it does have the advantage, especially for second tier mobile operators, of being similar to cellular networks to implement and manage and providing good interoperability with the various flavours of 3G. Its natural home, then, is in extending the networks of the mobile carriers in outlying regions, but it is keen to attack the hotspot sector too, an ambition that will be hard to realize in the face of WiMAX. However, the case that the company’s chief executive, Chris Gilbert, makes for IPWireless over Wi-Fi hotspots is valid for all BWA technologies. He points out that users will not want to have to hunt for hotspots, and that broadband alternatives can offer not only longer distances from the base station, but also mobility – as supported by IPWireless and by the mobile version of WiMAX, 802.16e. Another backhaul option that has gained coverage recently is free space optical, a technology that is primarily used to extend local fiber networks but can also be used for backhaul. One supplier specifically targeting this new direction is Omnilux. FSO is more expensive than wireless - $1,500 per node for

Omnilux, which is cheap by FSO standards – but each node operates at 100Mbps and has routing and quality of service capabilities plus embedded Wi-Fi. Unlikely to be mainstream, but meshes of these nodes could also be an attractive option for some enterprises. And of course there is satellite. There have been several announcements recently of combined satellite/Wi-Fi products that bundle an 802.11 access point with the satellite system. Satellite provides the backhaul to a fixed antenna, which then transmits the connection locally using Wi-Fi. This is a very expensive option of course, so mainly targeted at areas where there is no alternative. For instance, an island in Alaska gained a ‘satellite broadband hotspot’ last week, with Wi-Fi providing a simpler last mile option than other fixed wireless approaches. Another approach, entirely outside the cellular operators’ remit, is to extend the capacity of Wi-Fi. Companies such as Vivato, Ricochet and 5G Wireless have been developing technologies to extend the distances covered by 802.11 standards without the usual line of sight requirement – although their future looks uncertain, given that WiMAX will solve the problem in a year. Companies such as 5G and Vivato do use standard IEEE approaches and so have an advantage over some more individualistic solutions to providing a wireless alternative to DSL in the broadband last mile, though they cannot come close to WiMAX’ 70Mbps or its distances. 5G has conducted a trial in its home state of California, connecting buildings four miles apart, with no line of sight, at sustained throughput speed of 3Mbps. It claims its technology can achieve up to 5Mbps over eight to 10 miles. 5G claims that such performance makes Wi-Fi a viable option for metropolitan areas and campus-based corporations and will look to sign up ISP, corporate or municipal authority customers in the coming weeks. Band speed acquired its proprietary, patent pending WWAN technology with Wireless Think Tank last year. It operates in the 2.4GHz and 5.3GHz ranges and uses three co-located radios as a base, supporting 750 clients within a radius of up to 10 miles. The cost of this facility is $15,000. 5G is working on a new configuration that will support 2,072 clients per colocation. This compares to the cost of an alternative approach, VPOP, used by some wireless last mile providers, which supports 170 clients per location for $38,000.

OFDM (orthogonal frequency division multiplexing):Support for OFDM (orthogonal frequency division multiplexing), which can continue to be implemented in various ways by different operators (the precise variant of OFDM can often be their key differentiator). OFDM is well established and is incorporated in some new generation carrier services as well as being fundamental to digital TV. It transmits multiple signals simultaneously across one cable or wireless transmission path, within separate frequencies, with the orthogonal element spacing these frequencies to avoid interference. It is also supported in the 802.11a WLAN standard. 802.16a has three PHY options: an OFDM with 256 subcarriers – the only option supported in Europe by the ETSI, whose rival HiperMAN standard is likely to be subsumed into WiMAX; OFDMA, with 2048 sub-carriers; and a single carrier option for vendors that think they can beat multipath problems in this mode. OFDM will almost certainly become dominant in all wireless technologies including cellular and its industry body, the OFDM Forum, is a founder member of WiMAX Forum. Support for Smart Antenna:Smart antenna mechanisms are one of the most important methods of improving spectral efficiency in non-cellular wireless networks. 802.16 standards allow vendors to support a variety of these mechanisms, which can be a key performance differentiator. Smart antennas are one of the most interesting approaches to restructuring the network in order to support more users at fast rates, offering broadband performance and quality over a wireless link. Smart antenna suppliers cut the number of base stations by using multiple antennas in parallel, making highly efficient use of the available spectrum. They can be implemented as a more efficient technology for 3G carriers, but can also operate as a separate network to challenge 3G. Dynamic frequency selection in unlicensed spectrum: Spectral Efficiency:This is critical to support difficult user environments with hundreds of users per channel at high bandwidth and a mixture of continuous and burst traffic.

Protocol Independent Core:VII. TECHNICAL SPECIFICATIONS OF 802.16A 802.16 operate at up to 124Mbps in the 28MHz channel (in 10-66GHz), 802.16a at 70Mbps in lower frequency, 2-11GHz spectrum. Fundamental technologies in 802.16a:

WiMAX can transport IPv4, IPv6, Ethernet or ATM and others, supporting multiple services simultaneously and with quality of service. Mesh:Mesh Mode is an optional topology for subscriber-tosubscriber communication in non-line of sight 802.16a. It is

included in the standard to allow overlapping, ad hoc networks in the unlicensed spectrum and extend the edges of the WMAN’s range at low cost. Mesh support has recently been extended into the licensed bands too.

structured channel pairs do not exist, TDD uses a single channel for both upstream and downstream transmissions, dynamically allocating bandwidth depending on traffic requirements. Security:802.16 also include measures for privacy and encryption: authentication with x.509 certificates and data encryption using DES in CBC (cipher block chaining) mode with hooks defined for stronger algorithms like AES. VIII. ADVANTAGES OF WiMAX

Figure 1: Mesh networking

Although it has highly complex topology and messaging, mesh is a good alternative to the usual NLOS, as it scales well and addresses license exempt interference. It allows a community to be densely seeded with WiMAX connections at low cost, with robust communications as there are multiple paths for traffic to take (see diagram). Bandwidth on demand (frame by frame): Quality of Service:The ‘b’ extension to 802.16 is concerned with quality of service (QoS), which enables NLOS operation without severe distortion of the signal from buildings, weather and vehicles. It also supports intelligent prioritization of different forms of traffic according to its urgency. Mechanisms in the Wireless MAN MAC provide for differentiated QoS to support the different needs of different applications. For instance, voice and video require low latency but tolerate some error rate, while most data applications must be error-free, but can cope with latency. The standard accommodates these different transmissions by using appropriate features in the MAC layer, which is more efficient than doing so in layers of control overlaid on the MAC. Adaptive Modulation:Many systems in the past decade have involved fixed modulation, offering a trade-off between higher order modulation for high data rates, but requiring optimal links, or more robust lower orders that will only operate at low data rates. 802.16a supports adaptive modulation, balancing different data rates and link quality and adjusting the modulation method almost instantaneously for optimum data transfer and to make most efficient use of bandwidth. FDD and TDD:The standard also supports both frequency and time division duplexing (FDD and TDD) to enable interoperability with cellular and other wireless systems. FDD, the legacy duplexing method, has been widely deployed in cellular telephony. It requires two channel pairs, one for transmission and one for reception, with some frequency separation between them to mitigate self-interference. In regulatory environments where

Broadband wireless access provides more capacity at lower cost than DSL or cable for extending the fiber networks and supporting multimedia and fast internet applications in the enterprise or home. But it has been held back by the lack of a standard, so that solutions have been based on proprietary, single-vendor efforts. Standardization through the IEEE 802.16 specification raises the potential to: •

• •

•

Stall wired broadband and make wireless the key platform of the future Extend the range of Wi-Fi so that the myth of ubiquitous wireless can become a reality. Provide an alternative or complement to 3G Provide an economically viable communications infrastructure for developing countries and mobile black spot regions in developed nations IX. WiMAX APPLICATIONS

This figure shows some of the applications that WiMAX systems can be used for. This diagram shows that WiMAX can provide wireless broadband Internet access, telephone access services, television service access and mobile telephone services.

Figure 8. Wireless Broadband

Figure 9. Telephone Bypass

Figure 10. Digital Televisions

As the FCC and equivalent authorities in other parts of the world become more friendly to freeing up new spectrum, more broadband WISPs will spring up, especially if the US administration gives into pressure to open up some unused MMDS wireless broadband spectrum. WiMAX operates in a mixture of licensed and unlicensed spectrum, and the initial products will be focused on 2.5GHz and 3.5GHz licensed and 5.8GHz unlicensed bands (though the full standard supports a far wider range of bands). The licensed spectrum gives operators the chance to apply for franchises for fixed wireless broadband provision, especially in rural and remote areas, and to build the infrastructure with low cost, commodity hardware Something Intel is promoting assiduously as a means to increase investment in Centrino enabled PCs (it now has a director of rural broadband access).

Figure 11. Mobile Data & Cellular Bypass

In addition to higher-speed Internet access, mobile WiMAX can be used to provide voice-over-IP services in the future. The low-latency design of mobile WiMAX makes it possible to deliver VoIP services effectively. VoIP technologies may also be leveraged to provide innovative new services, such as voice chatting, push-to-talk, and multimedia chatting. New and existing operators may also attempt to use WiMAX to offer differentiated personal broadband services, such as mobile entertainment. The flexible channel bandwidths and multiple levels of quality-of-service (QoS) support may allow WiMAX to be used by service providers for differentiated high-bandwidth and low-latency entertainment applications. For example, WiMAX could be embedded into a portable gaming device for use in a fixed and mobile environment for interactive gaming. Other examples would be streaming audio services delivered to MP3 players and video services delivered to portable media players. As traditional telephone companies move into the entertainment area with IP-TV (Internet Protocol television), portable WiMAX could be used as a solution to extend applications and content beyond the home. Operators: For mobile operators, there is a doubled edged sword. WiMAX is particularly disruptive because no physical last mile installation is required and the base stations will cost under $20,000 using commodity standard hardware. As with Wi-Fi hotspots, fixed and mobile operators will have an equal interest in extending their networks through WiMAX, and also ensuring that any revenues lost to 3G and wired services are at least preserved within the company. But WiMAX also gives the opportunity for small, lternative operators to enter the game. License exempt wireless ISPs will start to offer WiMAX fixed wireless service. There are already about 1,800 such WISPs in the US, many just focused on Wi-Fi but some already eyeing the metro area. Before WiMAX, such operators had to either use Wi-Fi, or turn to proprietary BWA gear to provide features that Wi-FI lacks such as QoS.

Figure 12: Worldwide sub-11GHz subscriber base - 802.16a and proprietary

The unlicensed aspect means that independents have the chance to provide backhaul services for hotspots, which have the potential to create a nationwide wireless network. If the operators can control this, as they have been trying to do with Wi-Fi, they will be able to offer parallel, integrated services and achieve a stopgap as they struggle towards ubiquitous 3G – one with lower margins than cellular perhaps, but swifter ROI on lower upfront investment. They certainly have the power and resource to take control from alternative network suppliers, but they may also be condemning their 3G investments to stillbirth. But the genie is out of the bottle now, and while the operators hesitate, the equipment makers are driving ahead, Intel in the vanguard, and Nokia, which has supported WiMAX from its earliest days, looking forward to the mobile standard and to the chance to add a new form of base station business to its ailing networks unit. X. SUMMARY Although the WiMAX movement continues to focus on mobile opportunities, it is the traditional fixed wireless market that will remain the technology's bread and butter through 2009. The worldwide wireless broadband audience of five million in 2005 is expected to grow by 40 percent yearly through 2010 and WiMAX vendors will be perfectly poised to take advantage of this building market.

In the report "802.16/WiMAX: Assessment of Fixed and Mobile Opportunities" a $3.4 billion annual opportunity for fixed and portable broadband equipment by 2010. "WiMAX will account for 50% of that multi-billion dollar market by the end of the decade, with much activity in the 3.5 GHz band." "The market for cable modem and digital subscriber line replacement is expanding today while WiMAX in the mobile network remains 3 years to 5 years away." The mobile WiMAX community is faced with political, technical and competitive challenges, the report finds, impacting time to market, which is paramount since the 802.16e specification is not yet finished. "Certified mobile WiMAX equipment will arrive during or after 2007 and mobile carriers typically test new technologies from 12 months to 18 months before implementing them throughout the network." WiMAX will still become a factor in the mobile market in the years to come since most operators will not commit to additional major upgrades prior to 2009 and the standard is gaining support. FLASH-OFDM, TD-CDMA and future revisions of 3GPP and 3GPP2 will also play a role in both the fixed and mobile markets. Some of these platforms, especially FLASH-OFDM, already have considerable technical and time to market advantages over mobile WiMAX. The study provides global and regional forecasts for fixed and mobile 802.16 and BWA base stations and CPE shipments and equipment revenues as well as fixed and mobile 802.16 and BWA subscribers and service revenues through 2010. 802.16 chipset shipments and revenues are also provided through 2010. XI. CONCLUSION WiMAX is the most important of the host of wireless standards emerging from the IEEE and 3G bodies. Its impact will owe much to Wi-Fi, which has created the interest in and market acceptance of wireless networking to enable WiMAX to flourish in the mainstream, not least by attracting Intel into the sector. But its effect on the world of business and consumer internet and wireless access will be far more profound. Within five years, we expect WiMAX to be the dominant technology for wireless networking. By that time it will be fully mobile as well as providing low cost fixed broadband access that will open up regions where internet access has so far not been practical. As the cellular operators move to IPbased fourth generation systems, they will embrace WiMAX as they are doing with the far more limited Wi-Fi. WiMAX will be the catalyst for a shakeout of operators, with some of the small independents falling to the large players, still hunting for a more profitable revenue stream than 3G. WiMAX will be the most significant technology to date in making wireless access ubiquitous and, as more free spectrum is opened up, in creating a major shake-up of the traditional shape of the wireless and mobile communications sector. REFERENCES 1.

Websites:

2.

•

www.google.com

•

www.wimax.com

•

www.wikipedia.com

•

www.ieee802.org

•

www.wimaxforum.org

•

www.arcchart.com

Referred Articles: •

“Air Interface for Fixed and Mobile Broadband Wireless Access Systems,” IEEE/ P802.16e

•

802.16/WiMAX Report Summary by Michael Wolleben