07-06-2010, 12:57 PM
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Wimax: The Next Broadband Wireless Revolution
Presented By:
Names : T.Snehalatha.
Y.Sunitha.
Class : 4/4 B.Tech (E.C.E).
ABSTRACT:
WiMax is the next step on the road to a wireless world, extending broadband wireless access to new locations and over longer distances. It will also significally reduces the cost of bringing broadband to new areas.
INTRODUCTION:
WiMax (worldwide Interoperability for Microwave Access) is the recently approved IEEE 802.16 wireless metropolitan area network (MAN) standard for wireless access. WiMax is the real wireless architecture by which the wireless access range can extended to 49.6Kms compared with Wi-Fi 91mts and Bluetoothâ„¢s 9mts. WiMax 802.16
has a single carrier modulation scheme that operates between 10GHz and 66GHz radio frequency and requires line of sight towers for the connection to work. The new ratified 802.16a extension uses a lower frequency range of 2GHz to 11GHz, and does not require line of sight towers. It also boasts 70Mbps data transfer rate that can support thousands of users.
Wi-Fi Vs WiMax:
Wi-Fi uses a small base station plugged into a high speed (broadband ) connection to page link laptops or Internet with in 50mts. Wi-Fi is undoubtedly popular.And is used mainly to provide wireless access inside homes, offices and schools.But few people seem to be prepared to pay much amount for Wi-Fi access in Ëœhotspotsâ„¢ like airports and railway stations.
WiMax is considered as the next step beyond Wi-Fi because it is optimized for broadband operation in a WAN. It already includes numerous advancements like quality of service, enhanced security, higher data rates and uses smart antenna technology which allows better use of the spectrum.
ARCHITECTURE OF WiMax:
The core components of a WiMax system are the subscriber station (SS) and the base station (BS). A BS and one or more SSâ„¢s can form a cell with point to multipoint (P2MP) structure. An 802.16 based system often uses fixed antenna at the subscriber station site. The antenna is mounted on the roof. Provisions such as adaptive antenna systems and sub channel stations are also supported by this system.
A BS typically uses either directional or omni directional antennas. A fixed SS typically uses directional antenna while mobile or portable SS uses an omni directional antenna. Multiple BSâ„¢s can be configured to form a cellular wireless network. The 802.16 standard also can be used in a point to point topology with pairs of directional antennas. This increases the effective range of the system compared to what can be achieved in the P2MP mode.
FUNDAMENTAL TECHNOLOGIES IN 802.16:
OFDM (Orthogonal Frequency Division Multiplexing):
It is fundamental technology in digitital TV. It transmits multiple signals simultaneously across the wireless transmission paths within separate frequencies to avoid interference. It is also supported in the WLAN standard. OFDM will almost certainly become dominant in all wireless technologies.
ADAPTIVE MODULATION:
Many systems in the past decade have involved in the fixed modulation, offering a trade off between higher order modulation for high data rates, but requiring optimal links or more robust lower order that will only operate at low data rates. But 802.16 supports adaptive modulation ,balancing different data rates and page link quality, making most efficient use of bandwidth.
FDD AND TDD:
The standard also supports both frequency and time division multiplexing to
enable interoperability with cellular and other wireless system. FDD has been widely deployed in cellular telephony. It requires two channel pairs. One for transmission and other for reception, with some frequency separation between them to migrate self-interference.TDD uses a single channel for both upstream and downstream transmissions, dynamically allocating bandwidth depending on traffic requirements.
POTENTIAL WiMax APPLICATIONS:
The WiMax 802.16 will provide solution to the following multiple broadband segments.
Cellular backhaul:
The robust bandwidth of 802.16 technology makes it an excellent choice for backhaul for the commercial enterprises, such as those providing ˜hotspots™,as well as for point “to-point backhaul applications.
Broadband to underserved and remote areas:
WiMax is a natural choice for under served rural and outlying areas with a low population density.
Broadband on demand:
It can help to accelerate the deployment of Wi-Fi hotspots especially in those areas not served by cable, in areas where the local telephone company may have a long lead time for providing a broadband service.
Best-connected wireless service:
WiMax has nomadic capabilities, which allow users to connect to WISP even when they roam outside their home or business, or go to another city that also has a WISP.
CHIP ADVANCES:
The main obstacles to long distance wireless communications are limitations on battery power and poor power efficiency. Regulation keeps the power levels low and the range of Wi-Fi signals short, to avoid the overcrowding of airwaves. But advances in DSP chips mean that weak signals can be deciphered, lengthening the distance that is practical for transmission, as well as improving distance and speed potential. Battery improvement is vital to make a WiMax cell phone a practicality.
Nokia is working on battery and handset chip designs towards this end. Intel is increasingly involved in next generation battery and processing power for mobile devices, including digital radios that can intelligently tune in to the most efficient network like Cellular,Wi-Fi,Bluetooth,WiMax.
TECHNOLOGY CONSIDERATIONS:
WiMax backers are also working to sort out problems with service providers who want low-cost systems that support portable devices and roaming. In the development cycle, WiMax is expected to support mobile wireless technology, that is wireless transmissions directly to mobile users. This will be similar in function to the General Packet Radio Service (GPRS).
Intel has now promised WiMax versions of its Centrino chipset for 2004, where as Nokia says it will have battery and other technical issues solved in time to launch a WiMax cell phone in 2005.
CONCLUSION:
With in 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 no far not been practical.WiMax will be the most significant technology in making wireless access ubiquitous and, as the free spectrum is opened up, in creating a major shake-up of the traditional shape of the wireless and mobile communications sector.
REFERENCES:
1) Information Technology magazine (October 2004)
2) google.com
3) houstuffworks.com
4) intelsemiworks.com
5) IEEE magazines
Wimax: The Next Broadband Wireless Revolution
Presented By:
Names : T.Snehalatha.
Y.Sunitha.
Class : 4/4 B.Tech (E.C.E).
ABSTRACT:
WiMax is the next step on the road to a wireless world, extending broadband wireless access to new locations and over longer distances. It will also significally reduces the cost of bringing broadband to new areas.
INTRODUCTION:
WiMax (worldwide Interoperability for Microwave Access) is the recently approved IEEE 802.16 wireless metropolitan area network (MAN) standard for wireless access. WiMax is the real wireless architecture by which the wireless access range can extended to 49.6Kms compared with Wi-Fi 91mts and Bluetoothâ„¢s 9mts. WiMax 802.16
has a single carrier modulation scheme that operates between 10GHz and 66GHz radio frequency and requires line of sight towers for the connection to work. The new ratified 802.16a extension uses a lower frequency range of 2GHz to 11GHz, and does not require line of sight towers. It also boasts 70Mbps data transfer rate that can support thousands of users.
Wi-Fi Vs WiMax:
Wi-Fi uses a small base station plugged into a high speed (broadband ) connection to page link laptops or Internet with in 50mts. Wi-Fi is undoubtedly popular.And is used mainly to provide wireless access inside homes, offices and schools.But few people seem to be prepared to pay much amount for Wi-Fi access in Ëœhotspotsâ„¢ like airports and railway stations.
WiMax is considered as the next step beyond Wi-Fi because it is optimized for broadband operation in a WAN. It already includes numerous advancements like quality of service, enhanced security, higher data rates and uses smart antenna technology which allows better use of the spectrum.
ARCHITECTURE OF WiMax:
The core components of a WiMax system are the subscriber station (SS) and the base station (BS). A BS and one or more SSâ„¢s can form a cell with point to multipoint (P2MP) structure. An 802.16 based system often uses fixed antenna at the subscriber station site. The antenna is mounted on the roof. Provisions such as adaptive antenna systems and sub channel stations are also supported by this system.
A BS typically uses either directional or omni directional antennas. A fixed SS typically uses directional antenna while mobile or portable SS uses an omni directional antenna. Multiple BSâ„¢s can be configured to form a cellular wireless network. The 802.16 standard also can be used in a point to point topology with pairs of directional antennas. This increases the effective range of the system compared to what can be achieved in the P2MP mode.
FUNDAMENTAL TECHNOLOGIES IN 802.16:
OFDM (Orthogonal Frequency Division Multiplexing):
It is fundamental technology in digitital TV. It transmits multiple signals simultaneously across the wireless transmission paths within separate frequencies to avoid interference. It is also supported in the WLAN standard. OFDM will almost certainly become dominant in all wireless technologies.
ADAPTIVE MODULATION:
Many systems in the past decade have involved in the fixed modulation, offering a trade off between higher order modulation for high data rates, but requiring optimal links or more robust lower order that will only operate at low data rates. But 802.16 supports adaptive modulation ,balancing different data rates and page link quality, making most efficient use of bandwidth.
FDD AND TDD:
The standard also supports both frequency and time division multiplexing to
enable interoperability with cellular and other wireless system. FDD has been widely deployed in cellular telephony. It requires two channel pairs. One for transmission and other for reception, with some frequency separation between them to migrate self-interference.TDD uses a single channel for both upstream and downstream transmissions, dynamically allocating bandwidth depending on traffic requirements.
POTENTIAL WiMax APPLICATIONS:
The WiMax 802.16 will provide solution to the following multiple broadband segments.
Cellular backhaul:
The robust bandwidth of 802.16 technology makes it an excellent choice for backhaul for the commercial enterprises, such as those providing ˜hotspots™,as well as for point “to-point backhaul applications.
Broadband to underserved and remote areas:
WiMax is a natural choice for under served rural and outlying areas with a low population density.
Broadband on demand:
It can help to accelerate the deployment of Wi-Fi hotspots especially in those areas not served by cable, in areas where the local telephone company may have a long lead time for providing a broadband service.
Best-connected wireless service:
WiMax has nomadic capabilities, which allow users to connect to WISP even when they roam outside their home or business, or go to another city that also has a WISP.
CHIP ADVANCES:
The main obstacles to long distance wireless communications are limitations on battery power and poor power efficiency. Regulation keeps the power levels low and the range of Wi-Fi signals short, to avoid the overcrowding of airwaves. But advances in DSP chips mean that weak signals can be deciphered, lengthening the distance that is practical for transmission, as well as improving distance and speed potential. Battery improvement is vital to make a WiMax cell phone a practicality.
Nokia is working on battery and handset chip designs towards this end. Intel is increasingly involved in next generation battery and processing power for mobile devices, including digital radios that can intelligently tune in to the most efficient network like Cellular,Wi-Fi,Bluetooth,WiMax.
TECHNOLOGY CONSIDERATIONS:
WiMax backers are also working to sort out problems with service providers who want low-cost systems that support portable devices and roaming. In the development cycle, WiMax is expected to support mobile wireless technology, that is wireless transmissions directly to mobile users. This will be similar in function to the General Packet Radio Service (GPRS).
Intel has now promised WiMax versions of its Centrino chipset for 2004, where as Nokia says it will have battery and other technical issues solved in time to launch a WiMax cell phone in 2005.
CONCLUSION:
With in 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 no far not been practical.WiMax will be the most significant technology in making wireless access ubiquitous and, as the free spectrum is opened up, in creating a major shake-up of the traditional shape of the wireless and mobile communications sector.
REFERENCES:
1) Information Technology magazine (October 2004)
2) google.com
3) houstuffworks.com
4) intelsemiworks.com
5) IEEE magazines
