11-09-2013, 03:57 PM
Worldwide Interoperability for Microwave Access
[attachment=57908]
Abstract:
The two driving forces of modern Internet are broadband, and wireless. The WiMax standard
combines the two, delivering high-speed broadband Internet access over a wireless connection.
The main problems with broadband access are that it is pretty expensive and it doesn't reach all
areas. The main problem with WiFi access is that hot spots are very small, so coverage is sparse.
Here comes the technology of Wi-MAX, acronym for Worldwide Interoperability for
Microwave Access and goes by and it also goes by the IEEE name 802.16. This technology would
provide high speed of Broadband service, wireless access, and most importantly wide coverage
area unlike the Wi-Fi. Because it can be used over relatively long distances, it is an effective "last
mile" solution for delivering broadband to the home, and for creating wireless "hot spots" in places
like airports, college campuses, and small communities.
The so-called "last mile" of broadband is the most expensive and most difficult for
broadband providers
and Wi-MAX provides an easy solution. Although it is a wireless technology
unlike some other wireless technologies, it doesn't require a direct line of sight between the source
and endpoint, and it has a service range of 50 kilometers. It provides a shared data rate of up to
70Mbps, which is enough to service up to a thousand homes with high-speed access. Ultimately,
Wi-MAX may be used to provide connectivity to entire cities, and may be incorporated into laptops
to give users an added measure of mobility.
Introduction:
Wi-MAX 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. Wi-MAX delivers a point-to-
multipoint architecture, making it an ideal method for carriers to deliver broadband to locations
where wired connections would be difficult or costly. It may also provide a useful solution for
delivering broadband to rural areas where high-speed lines have not yet become available. A
WiMax connection can also be bridged or routed to a standard wired or wireless Local Area
Network (LAN).
WORKING:
In practical terms, WiMAX would operate similar to WiFi. 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. As
opposed to a traditional Internet Service Provider (ISP), which divides that bandwidth among
customers via wire, it uses a microwave link to establish a connection.
TECHNICAL ADVANTAGES OVER WiFi:
Because IEEE 802.16 networks use the same LLC layer (standardized by IEEE 802.2) as other
LANs and WANs, it can be both bridged and routed to them.
An important aspect of the IEEE 802.16 is that it defines a MAC layer that supports
multiple physical layer specifications. This is crucial to allow equipment makers to differentiate their
offerings. This is also an important aspect of why WiMAX can be described as a "framework for the
evolution of wireless broadband" rather than a static implementation of wireless technologies.
Enhancements to current and new technologies and potentially new basic technologies
incorporated into the PHY (physical layer) can be used. A converging trend is the use of multi-
mode and multi-radio SoCs and system designs that are harmonized through the use of common
MAC, system management, roaming, IMS and other levels of the system. WiMAX may be
described as a bold attempt at forging many technologies to serve many needs across many
spectrums.
The MAC is significantly different from that of Wi-Fi (and ethernet from which Wi-Fi is
derived). In Wi-Fi, the MAC uses contention access-all subscriber stations wishing to pass data
through an access point are competing for the AP's attention on a random basis. This can cause
distant nodes from the AP to be repeatedly interrupted by less sensitive, closer nodes, greatly
reducing their throughput. By contrast, the 802.16 MAC is a scheduling MAC where the subscriber
station only has to compete once (for initial entry into the network). After that it is allocated a time
slot by the base station. The time slot can enlarge and constrict, but it remains assigned to the
subscriber station meaning that other subscribers are not supposed to use it but take their turn.
This scheduling algorithm is stable under overload and oversubscription (unlike 802.11). It is also
much more bandwidth efficient. The scheduling algorithm also allows the base station to control
Quality of Service by balancing the assignments among the needs of the subscriber stations.
POTENTIAL APPLICATIONS:
WiMAX is a wireless metropolitan area network (MAN) technology that can connect IEEE 802.11
(Wi-Fi) hotspots with each other and to other parts of the Internet and provide a wireless alternative
to cable and DSL for last mile (last km) broadband access. IEEE 802.16 provides up to 50 km (31
miles) of linear service area range and allows connectivity between users without a direct line of
sight. Note that this should not be taken to mean that users 50 km (31 miles) away without line of
sight will have connectivity. Practical limits from real world tests seem to be around "3 to 5 miles" (5
to 8 kilometers). The technology has been claimed to provide shared data rates up to 70 Mbit/s,
which, according to WiMAX proponents, is enough bandwidth to simultaneously support more than
60 businesses with T1-type connectivity and well over a thousand homes at 1Mbit/s DSL-level
connectivity. Real world tests, however, show practical maximum data rates between 500kbit/s and
2 Mbit/s, depending on conditions at a given site.
SCENARIO OF WiMAX:
An Internet service provider sets up a WiMAX base station 10 miles from your home. You would
buy a WiMAX-enabled computer (some of them should be on store shelves in 2005) or upgrade
your old computer to add WiMAX capability. You would receive a special encryption code that
would give you access to the base station. The base station would beam data from the Internet to
your computer (at speeds potentially higher than today's cable modems), for which you would pay
the provider a monthly fee. The cost for this service could be much lower than current high-speed
Internet-subscription fees because the provider never had to run cables.
If you have a home network, things wouldn't change much. The WiMAX base station would
send data to a WiMAX-enabled router, which would then send the data to the different computers
on your network. You could even combine WiFi with WiMAX by having the router send the data to
the computers via WiFi.
Conclusion:
The IEEE 802.16 family of standards and its associated industry consortium, WiMax,
promise to deliver high data rates over large areas to a large number of users in the near future.
This exciting addition to current broadband options such as DSL, cable, and WiFi promises to
rapidly provide broadband access to locations in the world's rural and developing areas where
broadband is currently unavailable, as well as competing for urban market share.
The WiMAX protocol is designed to accommodate several different methods of data
transmission, one of which is Voice Over Internet Protocol (VoIP). VoIP allows people to make
local, long-distance and even international calls through a broadband Internet connection,
bypassing phone companies entirely. If WiMAX-compatible computers become very common, the
use of VoIP could increase dramatically. Almost anyone with a laptop could make VoIP calls.
[attachment=57908]
Abstract:
The two driving forces of modern Internet are broadband, and wireless. The WiMax standard
combines the two, delivering high-speed broadband Internet access over a wireless connection.
The main problems with broadband access are that it is pretty expensive and it doesn't reach all
areas. The main problem with WiFi access is that hot spots are very small, so coverage is sparse.
Here comes the technology of Wi-MAX, acronym for Worldwide Interoperability for
Microwave Access and goes by and it also goes by the IEEE name 802.16. This technology would
provide high speed of Broadband service, wireless access, and most importantly wide coverage
area unlike the Wi-Fi. Because it can be used over relatively long distances, it is an effective "last
mile" solution for delivering broadband to the home, and for creating wireless "hot spots" in places
like airports, college campuses, and small communities.
The so-called "last mile" of broadband is the most expensive and most difficult for
broadband providers
and Wi-MAX provides an easy solution. Although it is a wireless technology
unlike some other wireless technologies, it doesn't require a direct line of sight between the source
and endpoint, and it has a service range of 50 kilometers. It provides a shared data rate of up to
70Mbps, which is enough to service up to a thousand homes with high-speed access. Ultimately,
Wi-MAX may be used to provide connectivity to entire cities, and may be incorporated into laptops
to give users an added measure of mobility.
Introduction:
Wi-MAX 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. Wi-MAX delivers a point-to-
multipoint architecture, making it an ideal method for carriers to deliver broadband to locations
where wired connections would be difficult or costly. It may also provide a useful solution for
delivering broadband to rural areas where high-speed lines have not yet become available. A
WiMax connection can also be bridged or routed to a standard wired or wireless Local Area
Network (LAN).
WORKING:
In practical terms, WiMAX would operate similar to WiFi. 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. As
opposed to a traditional Internet Service Provider (ISP), which divides that bandwidth among
customers via wire, it uses a microwave link to establish a connection.
TECHNICAL ADVANTAGES OVER WiFi:
Because IEEE 802.16 networks use the same LLC layer (standardized by IEEE 802.2) as other
LANs and WANs, it can be both bridged and routed to them.
An important aspect of the IEEE 802.16 is that it defines a MAC layer that supports
multiple physical layer specifications. This is crucial to allow equipment makers to differentiate their
offerings. This is also an important aspect of why WiMAX can be described as a "framework for the
evolution of wireless broadband" rather than a static implementation of wireless technologies.
Enhancements to current and new technologies and potentially new basic technologies
incorporated into the PHY (physical layer) can be used. A converging trend is the use of multi-
mode and multi-radio SoCs and system designs that are harmonized through the use of common
MAC, system management, roaming, IMS and other levels of the system. WiMAX may be
described as a bold attempt at forging many technologies to serve many needs across many
spectrums.
The MAC is significantly different from that of Wi-Fi (and ethernet from which Wi-Fi is
derived). In Wi-Fi, the MAC uses contention access-all subscriber stations wishing to pass data
through an access point are competing for the AP's attention on a random basis. This can cause
distant nodes from the AP to be repeatedly interrupted by less sensitive, closer nodes, greatly
reducing their throughput. By contrast, the 802.16 MAC is a scheduling MAC where the subscriber
station only has to compete once (for initial entry into the network). After that it is allocated a time
slot by the base station. The time slot can enlarge and constrict, but it remains assigned to the
subscriber station meaning that other subscribers are not supposed to use it but take their turn.
This scheduling algorithm is stable under overload and oversubscription (unlike 802.11). It is also
much more bandwidth efficient. The scheduling algorithm also allows the base station to control
Quality of Service by balancing the assignments among the needs of the subscriber stations.
POTENTIAL APPLICATIONS:
WiMAX is a wireless metropolitan area network (MAN) technology that can connect IEEE 802.11
(Wi-Fi) hotspots with each other and to other parts of the Internet and provide a wireless alternative
to cable and DSL for last mile (last km) broadband access. IEEE 802.16 provides up to 50 km (31
miles) of linear service area range and allows connectivity between users without a direct line of
sight. Note that this should not be taken to mean that users 50 km (31 miles) away without line of
sight will have connectivity. Practical limits from real world tests seem to be around "3 to 5 miles" (5
to 8 kilometers). The technology has been claimed to provide shared data rates up to 70 Mbit/s,
which, according to WiMAX proponents, is enough bandwidth to simultaneously support more than
60 businesses with T1-type connectivity and well over a thousand homes at 1Mbit/s DSL-level
connectivity. Real world tests, however, show practical maximum data rates between 500kbit/s and
2 Mbit/s, depending on conditions at a given site.
SCENARIO OF WiMAX:
An Internet service provider sets up a WiMAX base station 10 miles from your home. You would
buy a WiMAX-enabled computer (some of them should be on store shelves in 2005) or upgrade
your old computer to add WiMAX capability. You would receive a special encryption code that
would give you access to the base station. The base station would beam data from the Internet to
your computer (at speeds potentially higher than today's cable modems), for which you would pay
the provider a monthly fee. The cost for this service could be much lower than current high-speed
Internet-subscription fees because the provider never had to run cables.
If you have a home network, things wouldn't change much. The WiMAX base station would
send data to a WiMAX-enabled router, which would then send the data to the different computers
on your network. You could even combine WiFi with WiMAX by having the router send the data to
the computers via WiFi.
Conclusion:
The IEEE 802.16 family of standards and its associated industry consortium, WiMax,
promise to deliver high data rates over large areas to a large number of users in the near future.
This exciting addition to current broadband options such as DSL, cable, and WiFi promises to
rapidly provide broadband access to locations in the world's rural and developing areas where
broadband is currently unavailable, as well as competing for urban market share.
The WiMAX protocol is designed to accommodate several different methods of data
transmission, one of which is Voice Over Internet Protocol (VoIP). VoIP allows people to make
local, long-distance and even international calls through a broadband Internet connection,
bypassing phone companies entirely. If WiMAX-compatible computers become very common, the
use of VoIP could increase dramatically. Almost anyone with a laptop could make VoIP calls.