26-04-2011, 01:01 PM
Submitted By:
Mamta Hooda
seminar1.doc (Size: 1.1 MB / Downloads: 51)
CHAPTER 1
ABSTRACT
Abstract. The term WIMAX (Worldwide Interoperability for Microwave Access) has become synonymous with the IEEE 802.16 Wireless Metropolitan Area Network (MAN) air interface standard. Filling the gap between Wireless LANs and wide area networks, WIMAX-compliant systems will provide a cost-effective fixed wireless alternative to conventional wire-line DSL and cable in areas where those technologies are readily available. The WIMAX technology can provide a cost-effective broadband access solution in areas beyond the reach of DSL and cable.
The ongoing evolution of IEEE 802.16 will expand the standard to address mobile applications thus enabling broadband access directly to WIMAX-enabled portable devices ranging from smart phones and PDAs to notebook and laptop computers. Thus WIMAX is going to be a revolution in the world of communications. First of all, it will suppose an explosion of the wireless data networks, being not a substitute but a complement to Wi-Fi, and if technology advances enough to get a good intercity wireless link, these networks could be comparable to the internet. It will mean also revolution in the world of mobile communications, being a serious competitor with UMTS. WIMAX Forum Certified products will extend the range of Wi-Fi networks from the local area to the metropolitan area and beyond. These products will be based upon the 802.16 standard and will support distances of up to 50 kilometers – far longer distances than supported by Wi-Fi products.
Word Count. 228
Keywords. IEEE 802.16, MAN, NLOS, PDA, UMTS, Wi-Fi.
CHAPTER 2
INTRODUCTION
“A new metropolitan-area wireless standard will change the economics of Internet access—again.”
It’s hard to buy a laptop computer today that doesn’t come with a Wi-Fi chip: a built-in radio that lets users surf the Web wirelessly from the boardroom, the bedroom, or the coffee bar. People love Wi-Fi because a single base station - a box with a wired connection to the Internet, such as a DSL, cable, or T1 line can broadcast to multiple users across distances as great as 100 meters indoors and 400 meters out-doors. But there’s a new technology on the way that will make Wi-Fi look feeble. IT’S CALLED WiMAX.
AND WiMAX provides wireless broadband Internet connections at speeds similar to Wi-Fi - but over distances of up to 50 kilometers from a central tower. “Metropolitan area” wireless networking at broadband speeds isn’t new, but the specialized equipment that receives the broadband signals has typically been too expensive for everyone but large businesses. Now that U.S. computing and communications firms are gradually reaching consensus on the details of the WiMAX standard, however, those prices could come down significantly. Industry agreement on details such as how to encrypt WiMAX signals, which frequencies to use, and how to provide multiple users with access to those frequencies will finally allow companies like Intel to manufacture mass quantities of WiMAX-enabled chips for use in broadband wireless equipment. And that’s expected to eventually bring WiMAX receivers into the $50 to $100 price range of today’s DSL and cable modems, meaning that millions of users could eventually drop their current Internet
Service Providers - often local phone or cable companies - and simply access the Internet over rooftop antennas at the other end of town.
CHAPTER 3
ABOUT WIMAX
WHAT IS WIMAX?
WiMAX is a wireless metropolitan-area network technology that provides interoperable broadband wireless connectivity to fixed, portable and nomadic users. It provides up to 50- kilometers of service area, allows users to get broadband connectivity without the need of direct line-of-sight to the base station, and provides total data rates up to 75 Mbps— enough bandwidth to simultaneously support hundreds of businesses and homes with a single base station. This white paper discusses wireless metro-access technologies: Wi-Fi with high gain antennas, Wi-Fi meshed networks and WiMAX. It explores how the technologies differ and how they can be combined to provide a total last-mile access solution now and in the future.
WiMAX is a standard-based technology which will serve as a wireless extension or alternative to cable and DSL for broadband access. Particularly for end users in rural, sparsely populated areas or in areas where laying cable is difficult or uneconomical, WiMAX will provide a new broadband access path to the internet.
CHALLENGES
Typical modified IEEE 802.11 network topologies associated with last-mile and hot-zone coverage use either directional antennas or a mesh-network topology. Wi-Fi provides the
certification for IEEE 802.11 client-to-access point (AP) communications. However, implementations of AP-to-AP and AP-to-service providers (that is, backhaul applications) that are typically needed for wireless last-mile and hot-zone coverage are still proprietary, thus providing little or no interoperability. Because the IEEE 802.11 standards were designed for unwiring the local area network (LAN), metro-access applications are facing the following challenges:
• Non-standard wireless inter-AP communication. Today, wireless links used to connect 802.11 APs for inter-AP communication in mesh networking are vendor-specific. The proposed IEEE 802.11s standard, estimated to be ratified in 2007, will standardize Wi-Fi mesh networking.
• Providing quality of service (QoS). QoS refers to the ability of the network to provide better service to selected network traffic over various technologies. The goal of QoS technologies is to provide priority (including dedicated bandwidth to control jitter and latency) that is required by some real-time and interactive traffic, while making sure that in so doing the traffic on the other paths does not fail. In general, unlicensed bands can be subject to QoS issues because deployment is open to anyone.
• Expensive backhaul costs. Backhaul refers both to the connection from the AP back to the provider and to the connection from the provider to the core network.
Despite the challenges, wireless metro-access solutions are continuously sought after for the following reasons:
• Wireless metro-access solutions available today, such as mesh networking implementations, are more cost-effective and flexible than their wired counterparts.
• These solutions provide a standards-based connection from AP-to-mobile users for hot-zone coverage.
• Local governments can provide free access for businesses or emergency services (such as police and fire fighters).
• Educational institutions can broaden learning through online collaboration between students and faculty on and off campus.
Mamta Hooda
seminar1.doc (Size: 1.1 MB / Downloads: 51)
CHAPTER 1
ABSTRACT
Abstract. The term WIMAX (Worldwide Interoperability for Microwave Access) has become synonymous with the IEEE 802.16 Wireless Metropolitan Area Network (MAN) air interface standard. Filling the gap between Wireless LANs and wide area networks, WIMAX-compliant systems will provide a cost-effective fixed wireless alternative to conventional wire-line DSL and cable in areas where those technologies are readily available. The WIMAX technology can provide a cost-effective broadband access solution in areas beyond the reach of DSL and cable.
The ongoing evolution of IEEE 802.16 will expand the standard to address mobile applications thus enabling broadband access directly to WIMAX-enabled portable devices ranging from smart phones and PDAs to notebook and laptop computers. Thus WIMAX is going to be a revolution in the world of communications. First of all, it will suppose an explosion of the wireless data networks, being not a substitute but a complement to Wi-Fi, and if technology advances enough to get a good intercity wireless link, these networks could be comparable to the internet. It will mean also revolution in the world of mobile communications, being a serious competitor with UMTS. WIMAX Forum Certified products will extend the range of Wi-Fi networks from the local area to the metropolitan area and beyond. These products will be based upon the 802.16 standard and will support distances of up to 50 kilometers – far longer distances than supported by Wi-Fi products.
Word Count. 228
Keywords. IEEE 802.16, MAN, NLOS, PDA, UMTS, Wi-Fi.
CHAPTER 2
INTRODUCTION
“A new metropolitan-area wireless standard will change the economics of Internet access—again.”
It’s hard to buy a laptop computer today that doesn’t come with a Wi-Fi chip: a built-in radio that lets users surf the Web wirelessly from the boardroom, the bedroom, or the coffee bar. People love Wi-Fi because a single base station - a box with a wired connection to the Internet, such as a DSL, cable, or T1 line can broadcast to multiple users across distances as great as 100 meters indoors and 400 meters out-doors. But there’s a new technology on the way that will make Wi-Fi look feeble. IT’S CALLED WiMAX.
AND WiMAX provides wireless broadband Internet connections at speeds similar to Wi-Fi - but over distances of up to 50 kilometers from a central tower. “Metropolitan area” wireless networking at broadband speeds isn’t new, but the specialized equipment that receives the broadband signals has typically been too expensive for everyone but large businesses. Now that U.S. computing and communications firms are gradually reaching consensus on the details of the WiMAX standard, however, those prices could come down significantly. Industry agreement on details such as how to encrypt WiMAX signals, which frequencies to use, and how to provide multiple users with access to those frequencies will finally allow companies like Intel to manufacture mass quantities of WiMAX-enabled chips for use in broadband wireless equipment. And that’s expected to eventually bring WiMAX receivers into the $50 to $100 price range of today’s DSL and cable modems, meaning that millions of users could eventually drop their current Internet
Service Providers - often local phone or cable companies - and simply access the Internet over rooftop antennas at the other end of town.
CHAPTER 3
ABOUT WIMAX
WHAT IS WIMAX?
WiMAX is a wireless metropolitan-area network technology that provides interoperable broadband wireless connectivity to fixed, portable and nomadic users. It provides up to 50- kilometers of service area, allows users to get broadband connectivity without the need of direct line-of-sight to the base station, and provides total data rates up to 75 Mbps— enough bandwidth to simultaneously support hundreds of businesses and homes with a single base station. This white paper discusses wireless metro-access technologies: Wi-Fi with high gain antennas, Wi-Fi meshed networks and WiMAX. It explores how the technologies differ and how they can be combined to provide a total last-mile access solution now and in the future.
WiMAX is a standard-based technology which will serve as a wireless extension or alternative to cable and DSL for broadband access. Particularly for end users in rural, sparsely populated areas or in areas where laying cable is difficult or uneconomical, WiMAX will provide a new broadband access path to the internet.
CHALLENGES
Typical modified IEEE 802.11 network topologies associated with last-mile and hot-zone coverage use either directional antennas or a mesh-network topology. Wi-Fi provides the
certification for IEEE 802.11 client-to-access point (AP) communications. However, implementations of AP-to-AP and AP-to-service providers (that is, backhaul applications) that are typically needed for wireless last-mile and hot-zone coverage are still proprietary, thus providing little or no interoperability. Because the IEEE 802.11 standards were designed for unwiring the local area network (LAN), metro-access applications are facing the following challenges:
• Non-standard wireless inter-AP communication. Today, wireless links used to connect 802.11 APs for inter-AP communication in mesh networking are vendor-specific. The proposed IEEE 802.11s standard, estimated to be ratified in 2007, will standardize Wi-Fi mesh networking.
• Providing quality of service (QoS). QoS refers to the ability of the network to provide better service to selected network traffic over various technologies. The goal of QoS technologies is to provide priority (including dedicated bandwidth to control jitter and latency) that is required by some real-time and interactive traffic, while making sure that in so doing the traffic on the other paths does not fail. In general, unlicensed bands can be subject to QoS issues because deployment is open to anyone.
• Expensive backhaul costs. Backhaul refers both to the connection from the AP back to the provider and to the connection from the provider to the core network.
Despite the challenges, wireless metro-access solutions are continuously sought after for the following reasons:
• Wireless metro-access solutions available today, such as mesh networking implementations, are more cost-effective and flexible than their wired counterparts.
• These solutions provide a standards-based connection from AP-to-mobile users for hot-zone coverage.
• Local governments can provide free access for businesses or emergency services (such as police and fire fighters).
• Educational institutions can broaden learning through online collaboration between students and faculty on and off campus.