This document discusses WiMAX technology and its applications. It begins by defining WiMAX and comparing it to other wireless technologies such as WiFi, DSL, and cable. It then addresses whether WiMAX will replace these existing broadband technologies. While WiMAX provides broadband wireless access not available in all areas, DSL and cable will likely continue to be deployed where infrastructure allows. The document goes on to describe the IEEE 802.16 standard that defines WiMAX and how it has evolved. It also explains WiMAX system models including point-to-point, point-to-multipoint, and mesh topologies. Finally, it covers WiMAX's use as a metro-access option and details its physical layer technology which is based
EMERGING BROADBAND WIRELESS TECHNOLOGIES: WIFI AND WIMAXcscpconf
Now-a-days there is high demand for broadband mobile services. Traditional high-speed
broadband solutions depend on wired technologies namely digital subscriber line (DSL). Wifi
and Wimax are useful in providing any type of connectivity such as the fixed or portable or
nomadic connectivity without the requirement of LoS (Line of Sight) of the base station. Mobile
Broadband Wireless Network (MBWN) is a flexible and economical solution for remote areas
where wired technology and also terminal mobility cannot be provided. The IEEE Wi-Fi and
Wi-Max/802.16 are the most promising technologies for broadband wireless metropolitan area networks (WMANs) and these are capable of providing high throughput even on long distances with varied QoS. These technologies ensure a wireless network that enables high speed Internet access to residential, small and medium business customers, as well as Internet access for WiFi hot spots and cellular base stations. These offer support to both point-to-multipoint (P2MP) and multipoint-to-multipoint (mesh) nodes and offers high speed data (voice, video) service to the customers. In this paper, we study the issues related to, benefits and deployment of these technologies.
The document discusses broadband evolution and spectrum challenges. It provides an overview of du's broadband portfolio including fixed wireless broadband, HSPA+, and LTE technologies. Key points include du being the first in the UAE to deploy DC-HSPA+ nationwide. The document also discusses evolutions in fixed wireless broadband using OFDM technology, enhancements to HSPA+ through MIMO and dual carrier implementations, and du's LTE deployment strategy focusing on improved peak rates, coverage, and average throughput compared to HSPA.
The document discusses WiMax (Worldwide Interoperability for Microwave Access), which is a wireless technology that provides broadband connections over long distances at speeds up to 70 megabits per second without needing line-of-sight access to a base station. It is based on IEEE 802.16 standards and is expected to replace or complement existing wireless technologies like WiFi and Bluetooth by offering higher speeds and longer ranges. The document covers WiMax's technical details, working mechanisms, applications and its potential to enable widespread wireless broadband access.
The WiMAX MAC encapsulates data packets from higher layers through various sublayers. It adds headers at each sublayer for functions like security, bandwidth allocation, and multiple access control before the data is encoded and transmitted through the physical layer using modulation schemes like OFDM. This ensures efficient transmission of data over the wireless medium according to QoS priorities and security requirements.
This document discusses WiMAX (Worldwide Interoperability for Microwave Access), a wireless technology based on IEEE 802.16 standards that can provide broadband connections over long distances. It defines key terms, describes applications of WiMAX for both fixed and mobile use, how WiMAX systems work, competing technologies, current deployments, benefits compared to other options, and initiatives to bring WiMAX to Pakistan.
The document discusses WiMAX technology and its use of OFDM to address bottleneck problems in high-speed networks. It describes how WiMAX uses OFDM to efficiently allocate bandwidth and share it between connecting nodes based on their data request sizes, in order to prevent data loss. It also provides background on WiMAX architecture and management, and how it can support high-speed point-to-point and point-to-multipoint connections with optimized handover and security features.
WiMax offers some advantages over WiFi.WiMax is the real wireless architecture by which the wireless access range can extended to 49.6Kms compared with Wi-Fi 91mts and Bluetooth’s 9mts. WiMax used to provide connectivity to entire cities, and may be incorporated into laptops to give users an added measure of mobility.
In 2002, Liberty Technologies, then exclusively an infrastructure provider to ISPs in Panama, was assigned a portion of the 3.5-GHz spectrum by the Panamanian government. Liberty launched a residential network service based on Time Division-Synchronous Code Division Multiple Access (TD-SCDMA) wireless networking technology. The company determined that deploying a wired or cable service would be prohibitively expensive and would not allow for a competitively priced broadband service. Instead, a wireless network could be deployed quickly and inexpensively and had a promising future as a WAN access technology.
EMERGING BROADBAND WIRELESS TECHNOLOGIES: WIFI AND WIMAXcscpconf
Now-a-days there is high demand for broadband mobile services. Traditional high-speed
broadband solutions depend on wired technologies namely digital subscriber line (DSL). Wifi
and Wimax are useful in providing any type of connectivity such as the fixed or portable or
nomadic connectivity without the requirement of LoS (Line of Sight) of the base station. Mobile
Broadband Wireless Network (MBWN) is a flexible and economical solution for remote areas
where wired technology and also terminal mobility cannot be provided. The IEEE Wi-Fi and
Wi-Max/802.16 are the most promising technologies for broadband wireless metropolitan area networks (WMANs) and these are capable of providing high throughput even on long distances with varied QoS. These technologies ensure a wireless network that enables high speed Internet access to residential, small and medium business customers, as well as Internet access for WiFi hot spots and cellular base stations. These offer support to both point-to-multipoint (P2MP) and multipoint-to-multipoint (mesh) nodes and offers high speed data (voice, video) service to the customers. In this paper, we study the issues related to, benefits and deployment of these technologies.
The document discusses broadband evolution and spectrum challenges. It provides an overview of du's broadband portfolio including fixed wireless broadband, HSPA+, and LTE technologies. Key points include du being the first in the UAE to deploy DC-HSPA+ nationwide. The document also discusses evolutions in fixed wireless broadband using OFDM technology, enhancements to HSPA+ through MIMO and dual carrier implementations, and du's LTE deployment strategy focusing on improved peak rates, coverage, and average throughput compared to HSPA.
The document discusses WiMax (Worldwide Interoperability for Microwave Access), which is a wireless technology that provides broadband connections over long distances at speeds up to 70 megabits per second without needing line-of-sight access to a base station. It is based on IEEE 802.16 standards and is expected to replace or complement existing wireless technologies like WiFi and Bluetooth by offering higher speeds and longer ranges. The document covers WiMax's technical details, working mechanisms, applications and its potential to enable widespread wireless broadband access.
The WiMAX MAC encapsulates data packets from higher layers through various sublayers. It adds headers at each sublayer for functions like security, bandwidth allocation, and multiple access control before the data is encoded and transmitted through the physical layer using modulation schemes like OFDM. This ensures efficient transmission of data over the wireless medium according to QoS priorities and security requirements.
This document discusses WiMAX (Worldwide Interoperability for Microwave Access), a wireless technology based on IEEE 802.16 standards that can provide broadband connections over long distances. It defines key terms, describes applications of WiMAX for both fixed and mobile use, how WiMAX systems work, competing technologies, current deployments, benefits compared to other options, and initiatives to bring WiMAX to Pakistan.
The document discusses WiMAX technology and its use of OFDM to address bottleneck problems in high-speed networks. It describes how WiMAX uses OFDM to efficiently allocate bandwidth and share it between connecting nodes based on their data request sizes, in order to prevent data loss. It also provides background on WiMAX architecture and management, and how it can support high-speed point-to-point and point-to-multipoint connections with optimized handover and security features.
WiMax offers some advantages over WiFi.WiMax is the real wireless architecture by which the wireless access range can extended to 49.6Kms compared with Wi-Fi 91mts and Bluetooth’s 9mts. WiMax used to provide connectivity to entire cities, and may be incorporated into laptops to give users an added measure of mobility.
In 2002, Liberty Technologies, then exclusively an infrastructure provider to ISPs in Panama, was assigned a portion of the 3.5-GHz spectrum by the Panamanian government. Liberty launched a residential network service based on Time Division-Synchronous Code Division Multiple Access (TD-SCDMA) wireless networking technology. The company determined that deploying a wired or cable service would be prohibitively expensive and would not allow for a competitively priced broadband service. Instead, a wireless network could be deployed quickly and inexpensively and had a promising future as a WAN access technology.
Cable modems allow high-speed internet access over existing cable TV networks. They have the potential to provide internet speeds over 100 times faster than traditional dial-up connections, at a lower cost. Cable modem systems work by sending data downstream from the cable headend to multiple users simultaneously, and sending data upstream from individual users to the headend. Early cable modem systems were proprietary, but standardization under DOCSIS has led to wider adoption and compatibility between equipment from different manufacturers. India is poised for significant growth in cable modem internet users as costs decline from traditional telephone-based access.
The document discusses the xMax wireless broadband technology. It provides an overview of the key components of the xMax network architecture, including xMod fixed/mobile hotspots, xAP access points, and the xMSC access network gateway. The xMax technology uses a proprietary protocol and is designed to prioritize voice calls by providing dedicated bandwidth and minimizing latency, allowing it to provide reliable voice services in shared spectrum.
WiMAX is a wireless broadband technology that provides transmission of data using a wireless signal. It supports transmission of up to 30 miles for fixed users and 5-15 km for mobile users. The IEEE 802.16 standard defines the WiMAX technology specifications. It has evolved over time to support different frequencies and applications. WiMAX provides high-speed broadband access and can serve as a wireless alternative to cable and DSL networks. However, it requires line-of-sight and can be affected by interference or heavy rain. Potential applications include cellular backhaul, residential broadband access, and connectivity in underserved areas.
WiMAX (802.16) is a wireless technology that provides broadband connectivity using the IEEE 802.16 standards. It was developed to provide "last mile" broadband access using wireless technology. Key features of WiMAX include the use of OFDMA, TDD, and MIMO to provide broadband speeds over long distances. It has applications for small business connectivity, wireless backhaul, nomadic broadband access, and private networks.
WiMAX has the potential to replace existing telecommunications infrastructure by providing broadband internet, phone, and TV services without the need for cables. It can do this through either fixed wireless or mobile configurations. WiMAX uses radio signals to transmit data between a base station and customer equipment up to 6 miles away, delivering speeds of around 40 Mbps. Key benefits of WiMAX include its ability to provide broadband connectivity to both businesses and homes from a single base station. Objections around interference, quality of service, security and reliability for wireless technologies are addressed through features in the WiMAX protocol like adaptive antenna systems and dynamic frequency selection.
This document analyzes the performance of different VoIP codecs over a WiMAX network using the network simulator NS2. The simulation varies parameters like the number of nodes and type of VoIP codec. Performance is evaluated based on metrics like throughput, average delay, and jitter. Results are presented graphically to compare these metrics for different codecs and number of nodes. The document provides background on VoIP codecs, IEEE 802.16 service flow classes, and simulation setup using NS2.
IEEE 802.16 is a standard for fixed wireless broadband access that provides high-speed internet access over long distances (up to 31 miles). It uses point-to-multipoint radio links to connect base stations to multiple subscriber stations and supports services like data, voice, and video. The standard defines the physical and medium access control layers for both licensed and unlicensed frequency bands below 11GHz to support residential and small business broadband connectivity as a cheaper alternative to fiber.
This document provides an overview of the IEEE 802.16 standard for Mobile WiMAX and beyond. It discusses key features of the WiMAX air interface including its physical layer, medium access control layer, and network architecture. The physical layer uses OFDM and supports features like adaptive modulation and coding, MIMO, and power control. The medium access control layer provides quality of service, scheduling, and error correction. The network architecture is based on an all-IP platform and supports mobility, security, and quality of service.
WiMAX is a wireless technology that provides broadband access over long distances. It can deliver high-speed internet access to both fixed and mobile users. WiMAX uses radio signals to transmit data between an antenna mounted on a structure like a tower and a wireless device. This allows it to provide broadband connectivity to areas where cable or DSL internet is unavailable or too expensive. WiMAX has advantages over WiFi like greater range, higher speeds, and less interference. While it promises high speeds and long ranges, its real-world performance depends on factors like line of sight, number of users, and environmental conditions. WiMAX can help provide emergency communications networks that are difficult to disrupt.
The document discusses the IEEE 802.16a standard for broadband wireless access and the role of WiMAX in driving adoption of the standard. The 802.16a standard specifies a protocol that supports applications like voice and video over wireless broadband, provides connectivity without line of sight, and can support hundreds to thousands of subscribers. WiMAX will help accelerate adoption of the standard by developing certification and interoperability test plans and awarding a "WiMAX Certified" label to certified equipment.
The document provides information about WiMAX including:
1) WiMAX is a wireless technology that provides broadband internet access over long distances, as an alternative to cable and DSL. It uses towers and receivers to connect devices to the internet.
2) A single WiMAX tower can provide coverage to a large area of up to 3,000 square miles using connections to other towers. This allows WiMAX to service remote rural areas.
3) WiMAX can provide both non-line-of-sight and line-of-sight services using different frequency ranges. It is suitable for applications like broadband access, connecting WiFi hotspots, and providing backup internet connections for businesses.
Future Technologies and Testing for Fixed Mobile Convergence,SAE and LTE in C...Going LTE
This white paper discusses future technologies for fixed-mobile convergence including LTE and SAE. It defines fixed-mobile convergence as providing consistent services via any fixed or mobile access point. The paper describes the motivation for convergence including mobility and consistent services. It outlines the LTE/SAE introduction and technologies including the evolved packet core and all-IP architecture. Key aspects of LTE such as physical layer channels and protocols are also summarized. The purpose is to support an integrated network through the IP Multimedia Subsystem for high-speed mobile experiences comparable to fixed broadband.
This document provides a comparative study of WiMAX and LTE networks. It summarizes key aspects of each network, including supported data rates and bandwidth, range, supported speeds, modulation techniques, frame structure, quality of service mechanisms, and security features. The document concludes with a comparison table highlighting that LTE supports higher data rates but shorter range compared to WiMAX, and different duplexing and frame allocation approaches between the two technologies.
This document summarizes a study that designed an integrated WiFi/WiMAX network using the QUALNET simulator. WiFi provides high data rates but short range, while WiMAX has lower data rates but much longer range. The study developed a coupler device that can receive WiMAX signals and convert them to WiFi, allowing seamless connectivity across both networks. This provides continuous coverage for users in high-rise buildings that may be outside WiFi range. The integrated network was analyzed in QUALNET and was found to provide high throughput, low delay, and consistent performance.
Wi Max Network Architecture V0.1 Pdf VersionDeepak Sharma
The document discusses the network architecture of WiMAX. It describes the key components of the WiMAX access service network (ASN) and connectivity service network (CSN), including the base stations, access gateway, home agent, AAA server, and their functions. It also outlines the WiMAX network reference points and profiles, as well as deployment strategies for fixed, mobile, and enterprise services.
This document compares the 4G wireless technologies WiMAX and 3GPP-LTE. It finds that while technically similar, WiMAX appears poised to reach the market sooner with initial deployments beginning in 2007-2008, while 3GPP-LTE deployments are not expected until 2010. WiMAX also has an earlier standard completion in 2005 versus 2007 for 3GPP-LTE. Due to its earlier timeline, the document concludes WiMAX is likely to be adopted by new service providers and those looking to offer mobile services sooner, while major UMTS providers will evolve to 3GPP-LTE over time.
The document discusses WiMAX technology and architecture. It provides an overview of the IEEE 802.16 standard, operating frequencies, data rates, network components, and services supported. The key components of a WiMAX network include the subscriber stations, access service network with base stations, connectivity service network with AAA and DHCP servers, and network service provider layer which offers various applications and services to subscribers.
Wireless routing (mesh) networks provide robust wireless coverage through their unique architecture. Every device serves as both an access point and part of the network infrastructure, automatically forwarding traffic for other devices. This allows the network to:
1. Self-configure into a microcellular structure, dramatically decreasing needed link distances and increasing scalability.
2. Automatically select the best RF links and multihop routes based on current propagation conditions, taking advantage of the best paths rather than needing to overcome the worst cases.
As more devices are added to a wireless routing network, the probability that a new subscriber will have coverage increases exponentially. This ensures full and continuous coverage at lower overall cost compared to traditional point-to-multipoint networks.
The document proposes ways to make schools safer by keeping the environment friendly with zero bullying, ensuring student safety, using multiple classroom levels and controlled access points to restrict intruders, installing bulletproof glass, security cameras, and metal detectors, and training teachers to calmly and effectively handle any situation.
Analisis sistem dan prosedur persediaan obat-obatan di Rumah Sakit Islam Unisma Malang untuk mendukung pengendalian intern. Studi kasus menganalisis sistem persediaan obat, mencakup fungsi, dokumen, catatan, dan prosedur. Hasilnya sistem persediaan obat rumah sakit bagus untuk pengendalian intern, tetapi perlu perbaikan pada sistem penghitungan fisik persediaan yang dapat menyebabkan kesalahan informasi pembelian.
Cable modems allow high-speed internet access over existing cable TV networks. They have the potential to provide internet speeds over 100 times faster than traditional dial-up connections, at a lower cost. Cable modem systems work by sending data downstream from the cable headend to multiple users simultaneously, and sending data upstream from individual users to the headend. Early cable modem systems were proprietary, but standardization under DOCSIS has led to wider adoption and compatibility between equipment from different manufacturers. India is poised for significant growth in cable modem internet users as costs decline from traditional telephone-based access.
The document discusses the xMax wireless broadband technology. It provides an overview of the key components of the xMax network architecture, including xMod fixed/mobile hotspots, xAP access points, and the xMSC access network gateway. The xMax technology uses a proprietary protocol and is designed to prioritize voice calls by providing dedicated bandwidth and minimizing latency, allowing it to provide reliable voice services in shared spectrum.
WiMAX is a wireless broadband technology that provides transmission of data using a wireless signal. It supports transmission of up to 30 miles for fixed users and 5-15 km for mobile users. The IEEE 802.16 standard defines the WiMAX technology specifications. It has evolved over time to support different frequencies and applications. WiMAX provides high-speed broadband access and can serve as a wireless alternative to cable and DSL networks. However, it requires line-of-sight and can be affected by interference or heavy rain. Potential applications include cellular backhaul, residential broadband access, and connectivity in underserved areas.
WiMAX (802.16) is a wireless technology that provides broadband connectivity using the IEEE 802.16 standards. It was developed to provide "last mile" broadband access using wireless technology. Key features of WiMAX include the use of OFDMA, TDD, and MIMO to provide broadband speeds over long distances. It has applications for small business connectivity, wireless backhaul, nomadic broadband access, and private networks.
WiMAX has the potential to replace existing telecommunications infrastructure by providing broadband internet, phone, and TV services without the need for cables. It can do this through either fixed wireless or mobile configurations. WiMAX uses radio signals to transmit data between a base station and customer equipment up to 6 miles away, delivering speeds of around 40 Mbps. Key benefits of WiMAX include its ability to provide broadband connectivity to both businesses and homes from a single base station. Objections around interference, quality of service, security and reliability for wireless technologies are addressed through features in the WiMAX protocol like adaptive antenna systems and dynamic frequency selection.
This document analyzes the performance of different VoIP codecs over a WiMAX network using the network simulator NS2. The simulation varies parameters like the number of nodes and type of VoIP codec. Performance is evaluated based on metrics like throughput, average delay, and jitter. Results are presented graphically to compare these metrics for different codecs and number of nodes. The document provides background on VoIP codecs, IEEE 802.16 service flow classes, and simulation setup using NS2.
IEEE 802.16 is a standard for fixed wireless broadband access that provides high-speed internet access over long distances (up to 31 miles). It uses point-to-multipoint radio links to connect base stations to multiple subscriber stations and supports services like data, voice, and video. The standard defines the physical and medium access control layers for both licensed and unlicensed frequency bands below 11GHz to support residential and small business broadband connectivity as a cheaper alternative to fiber.
This document provides an overview of the IEEE 802.16 standard for Mobile WiMAX and beyond. It discusses key features of the WiMAX air interface including its physical layer, medium access control layer, and network architecture. The physical layer uses OFDM and supports features like adaptive modulation and coding, MIMO, and power control. The medium access control layer provides quality of service, scheduling, and error correction. The network architecture is based on an all-IP platform and supports mobility, security, and quality of service.
WiMAX is a wireless technology that provides broadband access over long distances. It can deliver high-speed internet access to both fixed and mobile users. WiMAX uses radio signals to transmit data between an antenna mounted on a structure like a tower and a wireless device. This allows it to provide broadband connectivity to areas where cable or DSL internet is unavailable or too expensive. WiMAX has advantages over WiFi like greater range, higher speeds, and less interference. While it promises high speeds and long ranges, its real-world performance depends on factors like line of sight, number of users, and environmental conditions. WiMAX can help provide emergency communications networks that are difficult to disrupt.
The document discusses the IEEE 802.16a standard for broadband wireless access and the role of WiMAX in driving adoption of the standard. The 802.16a standard specifies a protocol that supports applications like voice and video over wireless broadband, provides connectivity without line of sight, and can support hundreds to thousands of subscribers. WiMAX will help accelerate adoption of the standard by developing certification and interoperability test plans and awarding a "WiMAX Certified" label to certified equipment.
The document provides information about WiMAX including:
1) WiMAX is a wireless technology that provides broadband internet access over long distances, as an alternative to cable and DSL. It uses towers and receivers to connect devices to the internet.
2) A single WiMAX tower can provide coverage to a large area of up to 3,000 square miles using connections to other towers. This allows WiMAX to service remote rural areas.
3) WiMAX can provide both non-line-of-sight and line-of-sight services using different frequency ranges. It is suitable for applications like broadband access, connecting WiFi hotspots, and providing backup internet connections for businesses.
Future Technologies and Testing for Fixed Mobile Convergence,SAE and LTE in C...Going LTE
This white paper discusses future technologies for fixed-mobile convergence including LTE and SAE. It defines fixed-mobile convergence as providing consistent services via any fixed or mobile access point. The paper describes the motivation for convergence including mobility and consistent services. It outlines the LTE/SAE introduction and technologies including the evolved packet core and all-IP architecture. Key aspects of LTE such as physical layer channels and protocols are also summarized. The purpose is to support an integrated network through the IP Multimedia Subsystem for high-speed mobile experiences comparable to fixed broadband.
This document provides a comparative study of WiMAX and LTE networks. It summarizes key aspects of each network, including supported data rates and bandwidth, range, supported speeds, modulation techniques, frame structure, quality of service mechanisms, and security features. The document concludes with a comparison table highlighting that LTE supports higher data rates but shorter range compared to WiMAX, and different duplexing and frame allocation approaches between the two technologies.
This document summarizes a study that designed an integrated WiFi/WiMAX network using the QUALNET simulator. WiFi provides high data rates but short range, while WiMAX has lower data rates but much longer range. The study developed a coupler device that can receive WiMAX signals and convert them to WiFi, allowing seamless connectivity across both networks. This provides continuous coverage for users in high-rise buildings that may be outside WiFi range. The integrated network was analyzed in QUALNET and was found to provide high throughput, low delay, and consistent performance.
Wi Max Network Architecture V0.1 Pdf VersionDeepak Sharma
The document discusses the network architecture of WiMAX. It describes the key components of the WiMAX access service network (ASN) and connectivity service network (CSN), including the base stations, access gateway, home agent, AAA server, and their functions. It also outlines the WiMAX network reference points and profiles, as well as deployment strategies for fixed, mobile, and enterprise services.
This document compares the 4G wireless technologies WiMAX and 3GPP-LTE. It finds that while technically similar, WiMAX appears poised to reach the market sooner with initial deployments beginning in 2007-2008, while 3GPP-LTE deployments are not expected until 2010. WiMAX also has an earlier standard completion in 2005 versus 2007 for 3GPP-LTE. Due to its earlier timeline, the document concludes WiMAX is likely to be adopted by new service providers and those looking to offer mobile services sooner, while major UMTS providers will evolve to 3GPP-LTE over time.
The document discusses WiMAX technology and architecture. It provides an overview of the IEEE 802.16 standard, operating frequencies, data rates, network components, and services supported. The key components of a WiMAX network include the subscriber stations, access service network with base stations, connectivity service network with AAA and DHCP servers, and network service provider layer which offers various applications and services to subscribers.
Wireless routing (mesh) networks provide robust wireless coverage through their unique architecture. Every device serves as both an access point and part of the network infrastructure, automatically forwarding traffic for other devices. This allows the network to:
1. Self-configure into a microcellular structure, dramatically decreasing needed link distances and increasing scalability.
2. Automatically select the best RF links and multihop routes based on current propagation conditions, taking advantage of the best paths rather than needing to overcome the worst cases.
As more devices are added to a wireless routing network, the probability that a new subscriber will have coverage increases exponentially. This ensures full and continuous coverage at lower overall cost compared to traditional point-to-multipoint networks.
The document proposes ways to make schools safer by keeping the environment friendly with zero bullying, ensuring student safety, using multiple classroom levels and controlled access points to restrict intruders, installing bulletproof glass, security cameras, and metal detectors, and training teachers to calmly and effectively handle any situation.
Analisis sistem dan prosedur persediaan obat-obatan di Rumah Sakit Islam Unisma Malang untuk mendukung pengendalian intern. Studi kasus menganalisis sistem persediaan obat, mencakup fungsi, dokumen, catatan, dan prosedur. Hasilnya sistem persediaan obat rumah sakit bagus untuk pengendalian intern, tetapi perlu perbaikan pada sistem penghitungan fisik persediaan yang dapat menyebabkan kesalahan informasi pembelian.
This document contains repeated text promoting the website OrganoGold.com/Powerpoint and its coffee and supplement products. It provides contact emails for individuals and repeatedly asks if the reader likes coffee and Organo Gold in an effort to advertise these products.
The document is a letter from The Boyd Capital Group confirming pre-approval of a $85,000 business purpose loan for Taylor Badstreet secured by a first trust deed on a property in Benedicta, ME. The terms include an 12% interest rate, 12 month interest-only payments of $850.78 billed through FCI Lender Services. Estimated lender and broker fees total $6,875. Closing is scheduled for February 15, 2013 contingent on meeting loan conditions like insurance and an appraisal by specified deadlines.
The document provides instructions for viewing a stereogram image of dice in 3D without special glasses. It explains that by crossing your eyes and letting them refocus, the reader will be able to see the hidden 3D image within the 2D picture. It suggests trying this technique to experience the depth perception created by a stereogram.
Prepared this slide for a workshop specializing in propulsion. This presentation gives a brief introdution to applications of CFD and FEA in assessing the performance of Ramjet and Turbine Intakes and Combustion modelling.
This document discusses controls for aerospace gas turbine engines. It begins with an overview of gas turbine components and typical control systems. It describes the evolution from mechanical to digital controls, including fully authority digital engine controls (FADEC). The document outlines requirements for fuel control and various control variables. It discusses challenges for intelligent gas turbine engines, including active component control, intelligent control and health monitoring, and distributed control with smart sensors.
Hybrid rockets use a liquid oxidizer and solid fuel. They are mechanically simpler than other rocket types and can provide denser fuels. A hybrid rocket consists of a pressure vessel containing liquid oxygen and a combustion chamber housing solid fuel. When thrust is desired, the liquid oxidizer flows into the combustion chamber where it reacts with the solid fuel surface in a boundary layer flame. Hybrid rockets offer higher safety during fabrication and operation compared to solid rockets, and allow for throttling capability not available with other rocket types. While hybrid rockets currently have some performance disadvantages, their safety features make them promising for future propulsion applications.
The document discusses policy implementation, which involves carrying out the activities designed by the legislative branch to achieve its policy goals. This includes establishing and staffing new agencies or assigning new responsibilities to existing agencies. The implementing agencies then translate the legislative intent into operational rules and guidelines, and coordinate resources and personnel to achieve the intended goals.
Education is central to development and empowerment. It lifts people out of poverty, promotes economic growth, and values democracy. Education can initiate social changes by changing attitudes and preparing for scientific and technological development, bringing changes to all aspects of life. Effective schools have a clear mission, high expectations, strong leadership, opportunities to learn, a safe environment, and monitor student progress. The benefits of education include improved health, increased productivity and earnings, reduced inequality, lower mortality rates, and increased women's participation in the workforce. Education also benefits society by driving economic competitiveness, reducing poverty, contributing to democracy, and promoting peace and environmental concern.
WiMAX is a wireless technology that provides broadband connections over long distances. It uses radio waves in the 2-11 GHz range to transmit data, allowing it to provide coverage over large areas of up to 50 km from the base station. WiMAX was developed to provide wireless internet access similar to cable or DSL but over longer distances and in more rural areas. It allows for speeds of up to 70 Mbps and can support both fixed and mobile broadband applications. While WiFi is better suited for short range indoor use due to its lower power and speeds of up to 54 Mbps.
This document summarizes a presentation on WiMAX technology given by two students. It discusses how WiMAX uses OFDMA to provide broadband wireless access without direct line of sight, allowing for growth in broadband applications. It describes key features of WiMAX's physical and MAC layers that provide quality of service, scalability, and efficient service in multipath environments. These include flexible channelization, adaptive burst profiles, space-time coding for diversity, and a centralized scheduling MAC to ensure bandwidth efficiency and bounded delays.
This document is a paper presentation on WiMAX technology by D. Anusha R. Manasa and R. Manasa from Brahmaiah College of Engineering in Nellore, India. The paper provides an overview of WiMAX, including its benefits over other wireless technologies such as longer range without line of sight connectivity, higher data rates, and improved quality of service and scalability. Key features of the WiMAX physical and MAC layers that enhance performance in multipath environments are described. The paper concludes that WiMAX can complement existing networks by providing cost-effective broadband wireless access.
THIS IS A PRESENTATION PREPARED BY ME AND MY PARTENER AS A CLASS PROJECT..DONT RATE IT VERY HIGH MYSELF COZ DID NOT SPENT MUCH TIME ON IT..BUT WIL WORK JUST FINE..DATA AVAILABLE WERE LATEST AND WE DID PUT AN EFFORT :)..
NO PDF BUT PPT FORMAT COZ DONT WANT TO TAKE CREDIT JUST HELP FELLOW STUDENTS...A THNX WUD DO....:)..IF U DONT LIKE THEN ALSO SAY..I'LL APPRECIATE IT
The presentation contains slides regarding various functions, components & uses of Wi-MAX. It compares the advantages of Wi-MAX over other technologies.
This document provides an overview and summary of WiMAX technology. It discusses:
1) WiMAX is a wireless technology that provides broadband connectivity without direct line-of-sight to a base station, addressing the need for higher bandwidth applications. It uses OFDM/OFDMA to divide spectrum into sub-carriers.
2) Key differences between WiMAX (IEEE 802.16) and other technologies like WiFi include greater bandwidth, encryption, and ability to support both indoor and outdoor use cases.
3) The PHY and MAC layers of WiMAX were designed to scale from one to hundreds of users per channel and provide quality of service, addressing limitations of technologies like WiFi.
The document discusses the WiMAX (IEEE 802.16) wireless broadband standard. It provides an overview of the standard, including its physical layer specifications and MAC layer features. Key points covered include WiMAX targeting wireless broadband services up to 31 miles at over 100 Mbps, its use of OFDM and OFDMA technologies, support for QoS and different data protocols, and comparisons between WiMAX and Wi-Fi standards.
The document discusses WiMAX (Worldwide Interoperability for Microwave Access) which is a wireless communication technology that provides broadband access over long distances. It describes key aspects of WiMAX including its standards, features, modes of operation, protocol stack, and comparisons to other wireless technologies. WiMAX uses radio waves to provide last mile wireless broadband connectivity and can operate in both line-of-sight and non-line-of-sight modes. The physical layer uses techniques like OFDM to transmit data over the wireless medium while the MAC layer organizes data packets and provides an interface between transport and physical layers.
This document summarizes a study that designed an integrated WiFi/WiMAX network using the QUALNET 5.0.1 simulator. The study aimed to provide seamless connectivity for subscribers across different network types. It provides an overview of WiFi and WiMAX technologies and their complementary characteristics. The designed system model includes a WiFi/WiMAX interworking module that converts between the different network signals to allow coupling and handover between WiFi and WiMAX networks. The study analyzed the integrated network's performance in terms of throughput, delay, and jitter.
WiMAX is a wireless technology that provides broadband access over long distances. It allows users to access the internet without wires by connecting to a WiMAX base station. Key points:
- WiMAX provides high-speed internet access to homes and businesses without wires using wireless technology outlined in IEEE 802.16 standards.
- It can be used for various applications including connecting Wi-Fi hotspots, providing broadband access, and providing mobile data for 4G services.
- WiMAX uses licensed or unlicensed spectrum and has an architecture with subscriber stations, access networks, and connectivity networks interconnected by standardized interfaces.
- It aims to eliminate constraints of Wi-Fi by providing greater mobility over longer distances and
3G networks faced issues accommodating mobile internet demand, including high costs of expanding networks. Performance was also low in densely populated and dead spot areas. IMT-Advanced networks were developed to address these issues by providing higher data rates, better mobility support, improved indoor coverage, and more compatible international roaming compared to 3G networks. WiMAX is a telecommunications technology that can provide wireless broadband internet over wide areas as an alternative to DSL and cable. It uses the IEEE 802.16 standard and can transmit data at distances of up to 30 miles.
WiMAX is a wireless communication technology that provides broadband internet access over long distances, surpassing the range of Wi-Fi. It uses IEEE 802.16 standards for wireless data transfer and can deliver speeds up to 1 Gbit/s for fixed locations and 75 Mbit/s for mobile use. WiMAX is used for internet access, mobile backhaul, and triple play services. It connects using various devices like indoor/outdoor gateways, external modems, and mobile phones that are certified by the WiMAX Forum to ensure interoperability.
WiMax was introduced to address limitations of existing wireless technologies like Bluetooth and WiFi that have short ranges and lower data rates. WiMax provides broadband connectivity over distances of up to 50km with data rates comparable to cable. It allows for quick deployment of wireless networks without the need for cables. Key features of WiMax include flexible network architectures, high security, support for multiple service levels, interoperability between equipment vendors, portability between base stations, and soon mobility for users.
The document discusses WiMAX (Worldwide Interoperability for Microwave Access), a wireless technology that provides broadband connections over long distances. WiMAX can provide broadband access to both fixed and mobile users, with speeds up to 70 Mbps. It has advantages over existing technologies like WiFi by providing broader coverage over distances of up to 50 km for lower costs. The document explores how WiMAX works, its standards, characteristics compared to WiFi, advantages and disadvantages, and its potential future applications in providing universal broadband connectivity.
WiMAX is a wireless technology that provides broadband internet access over long distances. It uses radio waves to transmit data and can provide connectivity up to 30 miles from a base station. WiMAX uses the IEEE 802.16 standard and consists of components like the base station, receiver, and antennas. It establishes connections like cellular networks but provides faster speeds than WiFi for connecting larger areas.
This document discusses WiMAX (Worldwide Interoperability for Microwave Access), a wireless technology that can provide broadband internet access over long distances. It describes WiMAX's ability to connect devices using wireless signals instead of cables. The document outlines WiMAX's history, how it works by transmitting signals between towers and receivers, its applications for broadband internet access, and its advantages of low cost and wide coverage though it has disadvantages like needing line of sight and being power intensive.
WiMAX has the potential to:
1) Extend public WiFi hotspots to provide metropolitan-wide mobile data coverage;
2) Connect enterprises and residents in urban and suburban areas where copper infrastructure is limited; and
3) Bridge the digital divide by delivering broadband access in low-density areas. WiMAX uses innovative technology to provide broadband wireless access at multiple Mbit/s data rates within a range of several kilometers. It will enable the "Portable Internet" experience on mobile devices.
Search Results
WiMAX (Worldwide Interoperability for Microwave Access) is a wireless industry coalition dedicated to the advancement of IEEE 802.16 standards for broadband wireless access (BWA) networks.
High frequency of low noise amplifier architecture for WiMAX application: A r...IJECEIAES
The low noise amplifier (LNA) circuit is exceptionally imperative as it promotes and initializes general execution performance and quality of the mobile communication system. LNA's design in radio frequency (R.F.) circuit requires the trade-off numerous imperative features' including gain, noise figure (N.F.), bandwidth, stability, sensitivity, power consumption, and complexity. Improvements to the LNA's overall performance should be made to fulfil the worldwide interoperability for microwave access (WiMAX) specifications' prerequisites. The development of front-end receiver, particularly the LNA, is genuinely pivotal for long-distance communications up to 50 km for a particular system with particular requirements. The LNA architecture has recently been designed to concentrate on a single transistor, cascode, or cascade constrained in gain, bandwidth, and noise figure.
136040819_wimxax_introduction and coverageAhmed963381
WIMAX stands for Worldwide Interoperability for Microwave Access and enables high-speed wireless transmission of data, voice, and video via portable devices. It provides broadband connectivity over long distances without wires using microwave frequencies. WIMAX networks can connect users to the internet from up to 30 miles away at cable modem-like speeds, allowing users to browse on laptops without being physically connected. It involves the wireless transfer of data using microwave frequencies and supports both fixed and mobile uses.
1. Gyan Prakash, Sadhana Pal / International Journal of Engineering Research and Applications (IJERA)
ISSN: 2248-9622 www.ijera.com Vol. 1, Issue 2, pp.327-336
WIMAX TECHNOLOGY AND ITS APPLICATIONS
1
Gyan Prakash, 2Sadhana Pal
1
(Lecturer in department of Electronics & Communication Engineering
Babu Banarasi Das Institute of Engineering Technology & Research Centre, Jahangirabad (U.P.)
2
(Assistant Professor in department of Electronics & communication Engineering
Vishweshwraya Institute of Engineering and Technology, Greater Noida (U.P.)
1. Abstract broadband technologies. In fact, many such countries are
This paper presents the features of the Worldwide already widely using proprietary broadband wireless
Interoperability for Microwave Access (WiMAX)
technology and future applications of WiMAX. A technologies. Even in such regions however, it is very
discussion is given by comparing WIMAX with unlikely that either Cable or DSL technologies would
DSL(Digital subscriber line) & Cable and Wireless Fidelity disappear. The business case and basic infrastructure often
(Wi-Fi). Several references have been included at the end
dictates that the cheapest solutions will predominate. In
of this paper for those willing to know in detail about
certain specific topics. many areas in developing nations, it may be cheaper to
deploy Cable and DSL in the cities at least for fixed
2. Introduction applications, whereas WiMAX will dominate outside of
WiMAX is an IP based, wireless broadband access major towns.
technology that provides performance similar to
802.11/Wi-Fi networks with the coverage and QOS (quality In the US, both Cable and DSL are growing extremely fast,
of service) of cellular networks. WiMAX is also an but are not available for all customers. Rural and remote
acronym meaning "Worldwide Interoperability for areas often lack broadband choices if any are available at
Microwave Access (WiMAX).
WiMAX is a wireless digital communications system, also all. When they are available, the DSL or cable plant may
known as IEEE 802.16, that is intended for wireless only exist within the town limits with no service outside the
"metropolitan area networks". WiMAX can provide city limits. This offers a compelling argument that low-
broadband wireless access (BWA) up to 30 miles (50 km)
cost WiMAX gear can leverage access to many new
for fixed stations, and 3 - 10 miles (5 - 15 km) for mobile
stations. In contrast, the WiFi/802.11 wireless local area customers. WiMAX also promises a whole new level of
network standard is limited in most cases to only 100 - 300 data access flexibility that will be much less location
feet (30 - 100m). specific for customers. This type of robust mobile, portable
WiMAX operates on both licensed and non-licensed
frequencies, providing a regulated environment and viable or fixed broadband access will be unprecedented.
economic model for wireless carriers. The average cell In addition, WiMAX will provide competitive options for
ranges for most WiMAX networks will likely boast 4-5 carriers and users that will benefit traditional wireline
mile range (in NLOS capable frequencies) even through
tree cover and building walls. Service ranges up to 10 carriers and customers by encouraging innovation and
miles (16 Kilometers) are very likely in line of sight (LOS) improved services.
applications (once again depending upon frequency). With the advent of IPTV fiber plays are enjoying
Mobile WiMAX capabilities on a per customer basis are
resurgence. It does not appear that WiMAX or broadband
much better than competing 3G technologies. WiMAX is
often cited to possess a spectral efficiency of 5 bps/Hz, wireless will be ready to deliver IPTV in the immediate
which is very good in comparison to other broadband future. However, fixed WiMAX may offer the best
wireless technologies, especially 3G.
potential for delivery of this potential content juggernaut.
More recently some promising new compression
3. Will WiMAX replace DSL and Cable?
technologies have reached the market. These technologies,
It is important to remember that WiMAX is a global
while still new, allow the delivery of true IP-based TV
broadband wireless standard. The question of whether or
signals to cellular devices. One company asserts that it
not it could replace either DSL or Cable will vary from
could deliver high definition TV (HDTV) in as little as 2.5
region to region. Many developing countries simply do not
Mbps of bandwidth, with standard resolution signal
have the infrastructure to support either cable or DSL
327 | P a g e
2. Gyan Prakash, Sadhana Pal / International Journal of Engineering Research and Applications (IJERA)
ISSN: 2248-9622 www.ijera.com Vol. 1, Issue 2, pp.327-336
requiring 1.5 Mbps. These speeds are within the potential
reach of WiMAX.
Qualcomm and its MediaFlo system are one good example
of such technologies. It is important to note that the
resolution of this TV or video system is not at the level of
standard TV, but progress is occurring rapidly.
4. IEEE 802.16
The IEEE developed the 802.16 in its first version to
address line of sight (LOS) access at spectrum ranges from
10 GHz to 66 GHz. The technology has evolved through
several updates to the standard such as 802.16a, 802.16c,
the Fixed WiMAX 802.16d (802.16-2004) specification
and lastly the mobile 802.16e set that are currently
commercially available. The upcoming 802.16m standard
is due to be ratified in 2010. The first update added support
for 2 GHz through 11 GHz spectrum with NLOS
6. WiMAX System
capability. Each update added additional functionality or A WiMAX system consists of two parts:
expanded the reach of the standard. • A WiMAX tower - similar in concept to a cell-phone
For example, the 802.16c revision added support for tower- A single WiMAX tower can provide coverage to a
very large area as big as 3,000 square miles (~8,000 square
spectrum ranges both licensed and unlicensed from 2 GHz km).
to 10 GHz. It also improved quality of service (QOS) and • A WiMAX receiver – The receiver and antenna could be
certain improvements in the media access control (MAC) a small box or PCMCIA card, or they could be built into a
laptop the way WiFi access is today.
layer along with adding support for the HiperMAN
A WiMAX tower station can connect directly to the
European standard. The number of supported physical Internet using a high bandwidth, wired connection (for
(PHY) layers was increased. Transport mediums such as example, a T3 line). It can also connect to another WiMAX
IP, Ethernet and asynchronous transfer mode (ATM) were tower using a line-of-sight, microwave link. This
connection to a second tower (often referred to as a
added. backhaul), along with the ability of a single tower to cover
Concentrated in 2- to 11-GHz WMAN, with the following up to 3,000 square miles, is what allows WiMAX to
set of features: provide coverage to remote rural areas.
Service area range 50 km Compared to the complicated wired network, a WiMAX
NLoS system only consists of two parts:
QoS designed in for voice/video, differentiated services The WiMAX base station (BS) and WiMAX subscriber
Very high spectrum utilization: 3.8 bit/Hz station (SS), also referred to as customer premise
Up to 280 Mbps per BS equipments (CPE). Therefore, it can be built quickly at a
Speed - 70 Mbps low cost. Ultimately, WiMAX is also considered as the
next step in the mobile technology evolution path. The
5. WiMAX—Evolution of the Technology potential combination of WiMAX and CDMA standards is
As the envisioned usage scenario has evolved over time, so referred to as 4G.
has evolved the technological basis of WiMAX. The IEEE 6.1 System Model
802.16 technical specification has now evolved through IEEE 802.16 supports two modes of operation: PTP and
three generations: PMP.
• IEEE 802.16: High data rate, highpower, PTP, LOS, fixed 6.1.1 Point-to-point (PTP)
SSs The PTP link refers to a dedicated link that connects only
• IEEE 802.16-2004: Medium data rate, PTP, PMP, fixed two nodes: BS and subscriber terminal. It utilizes resources
SSs in an inefficient way and substantially causes high
• IEEE 802.16-2005: Low-medium data rate, PTP, PMP, operation costs. It is usually only used to serve high-value
fixed or mobile SSs. customers who need extremely high bandwidth, such as
business high-rises, video postproduction houses, or
scientific research organizations. In these cases, a single
328 | P a g e
3. Gyan Prakash, Sadhana Pal / International Journal of Engineering Research and Applications (IJERA)
ISSN: 2248-9622 www.ijera.com Vol. 1, Issue 2, pp.327-336
connection contains all the available bandwidth to generate
high throughput. A highly directional and high-gain
antenna is also necessary to minimize interference and
maximize security.
6.1.2 Point-to-multipoint (PMP)
The PMP topology, where a group of subscriber terminals
are connected to a BS separately (shown in Figure), is a
better choice for users who do not need to use the entire
bandwidth. Under PMP topology, sectoral antennas with
highly directional parabolic dishes (each dish refers to a
sector) are used for frequency reuse. The available
bandwidth now is shared between a group of users, and the
cost for each subscriber is reduced.
7. WiMAX as a Metro-Access
Deployment Option
WiMAX is a worldwide certification addressing
interoperability across IEEE 802.16 standards-based
products. The IEEE 802.16 standard with specific revisions
addresses two usage models:
Fixed (IEEE 802.16d)
Portable (IEEE 802.16e)
7.1 Fixed (IEEE 802.16d)
6.1.3 Mesh Topology
Fixed WiMAX is the 802.16d standards or as it is
In addition to PTP and PMP, 802.16a introduces the mesh
topology, which is a more flexible, effective, reliable, and sometimes called 802.16-2004. Its product profile utilizes
portable network architecture based on the multihop the OFDM 256-FFT (Fast Fourier Transform) system
concept. Mesh networks are wireless data networks that profile, which is just different enough from its sister
give the SSs more intelligence than traditional wireless
transmitters and receivers. In a PMP network, all the standard of Mobile WiMAX (802.16e) that the two are
connections must go through the BS, while with mesh incompatible. Interestingly, both standards support both
topology, every SS can act as an access point and is able to protocols within the technology protocol as well as the one
route packets to its neighbors by itself to enlarge the
geographical coverage of a network. The architecture of a chosen for Mobile WiMAX and the Korean WiBro/Mobile
mesh system is shown in Figure. The routing across the WiMAX standard. If the Forum had elected to use an
network can be either proactive (using predetermined OFDMA version in Fixed WiMAX, it would have been far
routing tables) or reactive (generating routes on demand).
easier to provide an upgrade path.
This particular disconnect likely points to the emerging
understanding of the marketplace power of WiMAX. More
importantly, it indicates the power of the Korean
WiBro/Mobile WiMAX persuasion, which heavily
influenced the use of OFDMA® in the Mobile Standard.
The Fixed WiMAX 802.16-2004 standard supports both
time division duplex (TDD) and frequency division duplex
(FDD) services---the latter of which is far more popular
with mobile wireless providers than the newer TDD
329 | P a g e
4. Gyan Prakash, Sadhana Pal / International Journal of Engineering Research and Applications (IJERA)
ISSN: 2248-9622 www.ijera.com Vol. 1, Issue 2, pp.327-336
approach. systems as well as throughput.
At this point, Fixed WiMAX 802.16d systems are widely The 802.16e standard is being utilized primarily in licensed
deployed in both Europe and Asia, but it is clear that for spectrum for pure mobile applications. Many firms have
many vendors the adoption of the Mobile WiMAX 802.16e elected to develop the 802.16e standard exclusively for
is the option of choice. both fixed and mobile versions. The 802.16e version of
Having said this, the opening of the US 3.65 GHz spectrum WiMAX is the closest comparable technology to the
range has opened up a 802.16d opportunity in the US as emerging LTE mobile wireless standard. Or rather, it is
vendors adapt existing 3.5 GHz systems (and mostly Fixed more proper to say that LTE is the most comparable to
WiMAX based built for International use) radio systems to Mobile WiMAX in terms of capabilities as well as
use in this band. technology. The two competing technologies are really
7.2 Portable (IEEE 802.16e) very much alike technically.
The true Mobile WiMAX standard of 802.16e is divergent
from Fixed WiMAX. It attracted a significant number of 8. WiMAX Physical Layer
Forum members towards an opportunity to substantively The WiMAX physical layer is based on orthogonal
challenge existing 3G technology purveyors. While clearly frequency division multiplexing. OFDM is the transmission
scheme of choice to enable high-speed data, video, and
based on the same OFDM base technology adopted in multimedia communications and is used by a variety of
802.16-2004, the 802.16e version is designed to deliver commercial broadband systems, including DSL, Wi-Fi and
service across many more sub-channels than the OFDM Digital Video. Broadcast-Handheld (DVB-H), and
MediaFLO, besides WiMAX. OFDM is an elegant and
256-FFT. It is important to note that both standards efficient scheme for high data rate transmission in a non-
support single carrier, OFDM 256-FFT and at least line-of-sight or multipath radio environment.
OFDMA 1K-FFT. 8.1 OFDM Technology
Orthogonal frequency division multiplexing (OFDM)
The 802.16e standard adds OFDMA 2K-FFT, 512-FFT and
technology provides operators with an efficient means to
128-FFT capability. Sub-channelization facilitates access overcome the challenges of NLOS propagation. OFDM is
at varying distance by providing operators the capability to based on the traditional frequency division multiplexing
(FDM), which enables simultaneous transmission of
dynamically reduce the number of channels while
multiple signals by separating them into different frequency
increasing the gain of signal to each channel in order to bands (subcarriers) and sending them in parallel. In FDM,
reach customers farther away. The reverse is also possible. guard bands are needed to reduce the interference between
For example, when a user gets closer to a cell site, the different frequencies, which causes bandwidth wastage
.Therefore, it is not a spectrum-efficient and cost-effective
number of channels will increase and the modulation can solution. However, OFDM is a more spectrum-efficient
also change to increase bandwidth. At longer ranges, method that removes all the guard bands but keeps the
modulations like QPSK (which offer robust links but lower modulated signals orthogonal to mitigate the interference
level.
bandwidth) can give way at shorter ranges to 64 QAM
(which are more sensitive links, but offer much higher
bandwidth) for example. Each subscriber is linked to a
number of subchannels that obviate multi-path
interference. The upshot is that cells should be much less
sensitive to overload and cell size shrinkage during the load
than before. Ideally, customers at any range should receive
solid QOS without drops that 3G technology may
experience. Here is an in-depth Q&A on OFDMA®.
Comparison between FDM and OFDMA
The 802.16e version of WiMAX also incorporates support
for multiple-input-multiple-output (MIMO) antenna As shown in figure the required bandwidth in OFDM is
technology as well as Beamforming and Advanced significantly decreased by spacing multiple modulated
Antenna Systems (AAS), which are all "smart" antenna carriers closer until they are actually overlapping.OFDM
uses fast Fourier transform (FFT) and inverse FFT to
technologies that significantly improve gain of WiMAX convert serial data to multiple channels. The FFT size is
330 | P a g e
5. Gyan Prakash, Sadhana Pal / International Journal of Engineering Research and Applications (IJERA)
ISSN: 2248-9622 www.ijera.com Vol. 1, Issue 2, pp.327-336
256, which means a total number of 256 sub channels
(carriers) are defined for OFDM. In OFDM, the original
signal is divided into 256 subcarriers and transmitted in
parallel. Therefore, OFDM is referred to as a multicarrier
modulation scheme. Compared to single-carrier schemes,
OFDM is more robust against multipath propagation delay
owing to the use of narrower subcarriers with low bit rates
resulting in long symbol periods. A guard time is
introduced at each OFDM symbol to further mitigate the
effect of multipath delay spread.
The WiMAX OFDM waveform offers the advantage of
being able to operate with the larger delay spread of the
NLOS environment. By virtue of the OFDM symbol time
and use of a cyclic prefix, the OFDM waveform eliminates
the inter-symbol interference (ISI) problems and the
complexities of adaptive equalization. Because the OFDM
waveform is composed of multiple narrowband orthogonal For all of these reasons recent international standards such
carriers, selective fading is localized to a subset of carriers as those set by IEEE 802.16, ETSI BRAN, and ETRI, have
that are relatively easy to equalize. An example is shown established OFDM as the preferred technology of choice.
below as a comparison between an OFDM signal and a 8.2 OFDM Parameters in WiMAX
single carrier signal, with the information being sent in As mentioned previously, the fixed and mobile versions of
parallel for OFDM and in series for single carrier. WiMAX have slightly different implementations of the
OFDM physical layer. Fixed WiMAX, which is based on
IEEE 802.16- 2004, uses a 256 FFT-based OFDM physical
layer. Mobile WiMAX, which is based on the IEEE
802.16e-20055 standard, uses a scalable OFDMA-based
physical layer. In the case of mobile WiMAX, the FFT
sizes can vary from 128 bits to 2,048 bits.
8.2.1 Fixed WiMAX OFDM-PHY:
For this version the FFT size is fixed at 256, which 192
subcarriers used for carrying data, 8 used as pilot
subcarriers for channel estimation and synchronization
purposes, and the rest used as guard band subcarriers.6
Since the FFT size is fixed, the subcarrier spacing varies
with channel bandwidth. When larger bandwidths are used,
the subcarrier spacing increases, and the symbol time
decreases. Decreasing symbol time implies that a larger
fraction needs to be allocated as guard time to overcome
delay spread. WiMAX allows a wide range of guard times
that allow system designers to make appropriate trade-offs
between spectral efficiency and delay spread robustness.
For maximum delay spread robustness, a 25 percent guard
The ability to overcome delay spread, multi-path, and ISI in time can be used, which can accommodate delay spreads up
an efficient manner allows for higher data rate throughput. to 16 µs when operating in a 3.5MHz channel and up to 8
As an example it is easier to equalize the individual OFDM µs when operating in a 7MHz channel. In relatively benign
carriers than it is to equalize the broader single carrier multipath channels, the guard time overhead may be
signal. reduced to as little as 3 percent.
8.2.2 Mobile WiMAX OFDMA-PHY:
In mobile WiMAX, the FFT size is scalable from 128 to
2,048. Here, when the available bandwidth increases, the
FFT size is also increased such that the subcarrier spacing
is always 10.94 kHz. This keeps the OFDM symbol
duration, which is the basic resource unit, fixed and
therefore makes scaling have minimal impact on higher
layers. A scalable design also keeps the costs low. The
subcarrier spacing of 10.94 kHz was chosen as a good
balance between satisfying the delay spread and Doppler
spread requirements for operating in mixed fixed and
mobile environments. This subcarrier spacing can support
331 | P a g e
6. Gyan Prakash, Sadhana Pal / International Journal of Engineering Research and Applications (IJERA)
ISSN: 2248-9622 www.ijera.com Vol. 1, Issue 2, pp.327-336
delay spread values up to 20µs and vehicular mobility up to design includes a convergence sub layer that can interface
125 kmph when operating in 3.5GHz. A subcarrier spacing with a variety of higher-layer protocols, such as ATM,
of 10.94 kHz implies that 128, 512, 1,024, and 2,048 FFT TDM Voice, Ethernet, IP, and any unknown future
are used when the channel bandwidth is 1.25MHz, 5MHz, protocol. Given the predominance of IP and Ethernet in the
10MHz, and 20MHz, respectively. It should, however, be industry, the WiMAX Forum has decided to support only
noted that mobile WiMAX may also include additional IP and Ethernet at this time. Besides providing a mapping
bandwidth profiles. For example, a profile compatible with to and from the higher layers, the convergence sub layer
WiBro will use an 8.75MHz channel bandwidth and 1,024 supports MSDU header suppression to reduce the higher
FFT. This obviously will require different subcarrier layer overheads on each packet. The WiMAX MAC is
spacing and hence will not have the same scalability designed from the ground up to support very high peak bit
properties. rates while delivering quality of service similar to that of
8.3 Sub Channelization OFDMA ATM and DOCSIS. The WiMAX MAC uses a variable-
Sub Channelization in the uplink is an option within length MPDU and offers a lot of flexibility to allow for
WiMAX. Without sub channelization, regulatory their efficient transmission. For example, multiple MPDUs
restrictions and the need for cost effective CPEs, typically of same or different lengths may be aggregated into a single
cause the link budget to be asymmetrical, this causes the burst to save PHY overhead. Similarly, multiple MSDUs
system range to be up link limited. Sub channeling enables from the same higher-layer service may be concatenated
the link into a single MPDU to save MAC header overhead.
budget to be balanced such that the system gains are similar Conversely, large MSDUs may be fragmented into smaller
for both the up and down links. Sub channeling MPDUs and sent across multiple frames. Each MAC frame
concentrates the transmit power into fewer OFDM carriers; is prefixed with a generic MAC header (GMH) that
this is what increases the system gain that can either be contains a connection identifier (CID), the length of frame,
used to extend the reach of the system, overcome the and bits to qualify the presence of CRC, sub headers, and
building whether the payload is encrypted and if so, with which key.
penetration losses, and or reduce the power consumption of The MAC payload is either a transport or a management
the CPE. The use of sub channeling is further expanded in message. Besides MSDUs, the transport payload may
orthogonal frequency division multiple access (OFDMA) to contain bandwidth requests or retransmission requests. The
enable a more flexible use of resources that can support type of transport payload is identified by the sub header
nomadic or mobile operation. that immediately precedes it. Examples of sub headers are
packing sub headers and fragmentation sub headers.
WiMAX MAC also supports ARQ, which can be used to
request the retransmission of unfragmented MSDUs and
fragments of MSDUs. The maximum frame length is
2,047 bytes, which is represented by 11 bits in the GMH.
8.4.1 Channel-Access Mechanisms
In WiMAX, the MAC layer at the base station is fully
responsible for allocating bandwidth to all users, in both the
uplink and the downlink. The only time the MS has some
control over bandwidth allocation is when it has multiple
sessions or connections with the BS. In that case, the BS
allocates bandwidth to the MS in the aggregate, and it is up
to the MS to apportion it among the multiple connections.
All other scheduling on the downlink and uplink is done by
the BS. For the downlink, the BS can allocate bandwidth to
each MS, based on the needs of the incoming traffic,
without involving the MS. For the uplink, allocations have
to be based on requests from the MS. The WiMAX
standard supports several mechanisms by which an MS can
request and obtain uplink bandwidth. Depending on the
particular QoS and traffic parameters associated with a ser-
8.4 MAC-Layer Overview vice, one or more of these mechanisms may be used by the
The primary task of the WiMAX MAC layer is to provide MS. The BS allocates dedicated or shared resources
an interface between the higher transport layers and the periodically to each MS, which it can use to request
physical layer. The MAC layer takes packets from the bandwidth. This process is called polling. Polling may be
upper layer—these packets are called MAC service data done either individually (unicast) or in groups (multicast).
units (MSDUs)—and organize them into MAC protocol Multicast polling is done when there is insufficient
data units (MPDUs) for transmission over the air. For bandwidth to poll each MS individually. When polling is
received transmissions, the MAC layer does the reverse. done in multicast, the allocated slot for making bandwidth
The IEEE 802.16- 2004 and IEEE 802.16e-2005 MAC requests is a shared slot,
332 | P a g e
7. Gyan Prakash, Sadhana Pal / International Journal of Engineering Research and Applications (IJERA)
ISSN: 2248-9622 www.ijera.com Vol. 1, Issue 2, pp.327-336
overall power consumption of the CPE and the potential
interference with other co-located base stations. For LOS
the transmit power of the CPE is approximately
proportional to its distance from the base station, for NLOS
it is also heavily dependent on the clearance and
obstructions.
8.6 Adaptive Modulation
Adaptive modulation allows the WiMAX system to adjust
the signal modulation scheme depending on the signal to
noise ratio (SNR) condition of the radio link. When the
radio link is high in quality, the highest modulation scheme
is used, giving the system more capacity. During a signal
fade, the WiMAX system can shift to a lower modulation
scheme to maintain the connection quality and link
stability. This feature allows the system to overcome time-
selective fading. The key feature of adaptive modulation is
that it increases the range that a higher modulation scheme
can be used over, since the system can flex to the actual
fading conditions, as opposed to having a fixed scheme that
is budgeted for the worst case conditions.
8.7 Error Correction Techniques
Error correction techniques have been incorporated into
WiMAX to reduce the system signal to noise ratio
requirements. Strong Reed Solomon FEC, convolution
encoding, and interleaving algorithms are used to detect
and correct errors to improve throughput. These robust
error correction techniques help to recover error frames that
may have been lost due to frequency selective fading or
burst errors. Automatic repeat request (ARQ) is used to
correct errors that cannot be corrected by the FEC, by
having the error information resent. This significantly
improves the bit error rate (BER) performance for a similar
threshold level.
9. Competing technologies
which every polled MS attempts to use. WiMAX defines a Within the marketplace, WiMAX’s main competition
contention access and resolution mechanism for the case comes from widely deployed wireless systems with
when more than one MS attempts to use the shared slot. If overlapping functionality such as UMTS and CDMA2000,
it already has an allocation for sending traffic, the MS is as well as a number of Internet-oriented systems such as
not polled. Instead, it is allowed to request more HIPERMAN and WiBro .Both of the two major 3G
bandwidth by systems, CDMA2000 and UMTS, compete with WiMAX.
(1) Transmitting a stand-alone bandwidth request MPDU, Both offer DSL-class Internet access, in addition to phone
(2) Sending a bandwidth request using the ranging channel, service. UMTS has also been enhanced to compete directly
or with WiMAX in the form of UMTS-TDD, which can use
(3) Piggybacking a bandwidth request on generic MAC WiMAX-oriented spectrum, and it provides a more
packets. consistent (lower bandwidth at peak) user experience than
WiMAX (Figure). Moving forward, similar air interface
8.5 Power Control technologies to those used by WiMAX are being
Power control algorithms are used to improve the overall considered for the 4G evolution of UMTS.
performance of the system, it is implemented by the base
station sending power control information to each of the
CPEs to regulate the transmit power level so that the level
received at the base station is at a predetermined level. In a
dynamical changing fading environment this pre-
determined performance level means that the CPE only
transmits enough power to meet this requirement. The
converse would be that the CPE transmit level is based on
worst-case conditions. The power control reduces the
333 | P a g e
8. Gyan Prakash, Sadhana Pal / International Journal of Engineering Research and Applications (IJERA)
ISSN: 2248-9622 www.ijera.com Vol. 1, Issue 2, pp.327-336
Clearly, WiMAX and Wi-Fi are complementary
technologies and will remain so for the foreseeable future.
The widely available Wi-Fi technology used in hotspots in
hotels, restaurants, airports and even larger Wi-Fi zones in
some cities will continue to grow for many years. The
recent flurry of municipal Wi-Fi mesh networks has only
served to cement the technology into the wireless equation.
Wi-Fi is not going away any time soon.
As the WiMAX standard grows into its first highs scale
deployment with Clear wire in 2009 and continues to gain
acceptance and drive cost reductions, new chipsets that
incorporate the ability to function across multiple platforms
9.1 WiBro
WiBro (wireless broadband) is an Internet technology will become more common in general with the MAN
being developed by the Korean telecom industry (Figure). portion of this network technology slowly being converted
In February 2002, the Korean government allocated 100
to the more robust WiMAX systems, as the business cases
MHz of electromagnetic spectrum in the 2.3-GHz band,
and in late 2004, WiBro Phase 1 was standardized by the for hotspot venues merit. Basically, this means that
TTA (Telecommunications Technology Association) of WiMAX users in a few years will be able to not only access
Korea. WiBro is the newest variety of mobile wireless Wi-Fi hotspots at a café, but could also have mobile
broadband access. It is based on the same IEEE 802.16
standard as WiMAX but is designed to maintain citywide WiMAX access as well, along with access to other
connectivity on the go, tracking a receiver at speeds of up existing cellular technologies.
to 37 mi per hr (60 km/hr). WiMAX is the current standard Multiple network capability in a single device is gaining
in the United States, offering wireless Internet connectivity
to mobile users at fixed ranges of up to 31 mi (50 km) from traction and should be the norm in only a few years. Once
the transmitting base. However, it is not designed to be again, this points towards a complementary aspect to the
used while the receiver is in motion. WiBro can be thought two technologies. True mobile access users in many cases
of as mobile WiMAX, though the technology and its exact
will not require the level of bandwidth that they may need
specifications will change as it undergoes refinements
throughout its preliminary stages. when in a fixed location. The two technologies will fulfill
differing needs for consumers.
However, other LAN technology standards such as
Bluetooth, UHF Whitespace frequencies, Ultrawideband
and the 802.11n specification that offer value in shorter
range hotspot networks will all grow and necessitate
chipsets and laptop radios that will eventually be able to
seamlessly cross these shorter range data networks as well
as cellular networks and WiMAX citywide networks. The
WiMAX standard is a major part of the very bright vision
of the broadband wireless future that flexibility like this
promises. Though leaders in the industry often cite the
potential for true software defined radio systems, wherein a
user’s handset, laptop or other devices essentially scan for
the best connection for the location and spectrum available.
The industry is slowly moving in this direction; however,
expect the full development of this type of seamless
technology to be a few years away. Even moderate
10. Will WiMAX compete with Wi-Fi? incremental improvements in this direction could afford
334 | P a g e
9. Gyan Prakash, Sadhana Pal / International Journal of Engineering Research and Applications (IJERA)
ISSN: 2248-9622 www.ijera.com Vol. 1, Issue 2, pp.327-336
consumers benefits that are essentially impossible with systems, available bandwidth is shared between users in a
given radio sector, so performance could deteriorate in the
wireline technologies. case of many active users in a single sector. In practice,
many users will have a range of 2-, 4-, 6-, 8-, 10- or 12
Mbit/s services and additional radio cards will be added to
11. Benefits of WiMAX the base station to increase the capacity as required.
Component Suppliers Because of this, various granular and distributed network
• Assured wide market acceptance of developed and architectures are being incorporated into WiMAX through
components independent development and within the 802.16j mobile
• Lower production costs due to economies of scale multi-hop relay (MMR) task group. This includes wireless
• Reduced risk due to interoperability Equipment mesh, grids, network remote station repeaters which can
Manufacturers extend networks and connect to backhaul.
• Stable supply of low cost components and chips
• Freedom to focus on development of network elements 13. Future of WiMAX
consistent with core competencies, while knowing that 13.1 The IEEE 802.20 Standard
equipment will interoperate with third party products The IEEE 802.20 standard is a broadband wireless
• Engineering development efficiencies networking technology that is being standardized for
• Lower production costs due to economies of scale deployment by mobile communications service providers,
Operators and Service Providers in portions of their licensed spectrum. The capacity of
• Lower CAPEX – with lower cost base station, customer 802.20 is projected to be 2 Mbps per user, and its range is
premises equipment (CPE), and network deployment costs comparable to 3G cellular technologies, namely, up to 5
• Lower investment risk due to freedom of choice among km. More typical deployments will be in the neighborhood
multiple vendors and solutions of 1 to 3 km. Finalization of the 802.20 standard is not
• Ability to tailor network to specific applications by expected soon. The 802.20 standard has been under
mixing and matching equipment from different vendors development since late 2002, but the going has been slow,
• Improved operator business case with lower OPEX End to say the least. 802.20 and 802.16e, the mobile WiMAX
Users specification, appear similar at first glance but differ in the
• Lower subscriber fees frequencies they will use and the technologies they are
• Wider choice of terminals enabling cost performance based on. Standard 802.20 will operate below 3.5 GHz,
analysis whereas mobile WiMAX will work within the 2-GHz to 6-
• Portability of terminals when moving locations/networks GHz bands. Further, as the name suggests, 802.16e is based
from WiMAX operator “A” to operator “B” on WiMAX, with the goal of having WiMAX transmitters
• Lower service rates over time due to cost efficiencies in being able to support both fixed and mobile connections.
the delivery chain. Although the 802.20 group will be back at work later, the
802.20 technology is alluring, with promises of low-latency
12. Limitations 1-Mbps connections being sustained even at speeds of up to
A commonly-held misconception is that WiMAX will 150 mph, but we are going to have to wait a couple of years
deliver 70 Mbit/s over 50 kilometers. In reality, WiMAX for it.
can do one or the other — operating over maximum range
(50 km) increases bit error rate and thus must use a lower
bitrate. Lowering the range allows a device to operate at
higher bitrates. Typically, fixed WiMAX networks have a
higher-gain directional antenna installed near the client
(customer) which results in greatly increased range and
throughput. Mobile WiMAX networks are usually made of
indoor "customer premises equipment" (CPE) such as
desktop modems, laptops with integrated Mobile WiMAX
or other Mobile WiMAX devices. Mobile WiMAX devices
typically have an omni-directional antenna which is of
lower-gain compared to directional antennas but are more
portable. In practice, this means that in a line-of-sight
environment with a portable Mobile WiMAX CPE, speeds
of 10 Mbit/s at 10 km could be delivered However, in
urban environments they may not have line-ofsight and
therefore users may only receive 10 Mbit/s over 2 km.
Higher-gain directional antennas can be used with a Mobile
WiMAX network with range and throughput benefits but
the obvious loss of practical mobility. Like most wireless
335 | P a g e
10. Gyan Prakash, Sadhana Pal / International Journal of Engineering Research and Applications (IJERA)
ISSN: 2248-9622 www.ijera.com Vol. 1, Issue 2, pp.327-336
13.2 IEEE 802.16m have been introduced into the market that already contains
the WiMAX standard presented here. Market is the key
The 802.16m mobile WiMAX standard is a follow-on to word to take into account. Products will have to be
802.16e standard and is a candidate to the International delivered according to the market needs and those for end-
Telecom Union's (ITU) consideration as an IMT advanced users will have to be extremely easy to install. Experience
from DSL and cable modems services shows this
(4G) technology - specifically, providing downlink speeds
drawback. Of course, in addition to be easy to install and
of at least 100 Mbps in a wide area with high-mobility. provide good technical features, these products have to
The new 802.16m standard will provide increased provide low-cost or at least a clear advantage over other
performance advantages over 802.16e. From a technologies that are, at this moment,
already matured in the market like xDSL and cable modem.
technological perspective, 802.16m is capable of providing
up to 120 Mbps down and 60 Mbps up in an urban setting, 15. REFERENCES
using 4x2 MIMO antennas on a single 20MHz-wide [1] IEEE 802.16e: IEEE 802.16e Task Group (Mobile
channel. Even higher data rates can be achieved with WirelessMAN) http://www.ieee802.org/16/tge/.
[2] IEEE Std. 802.16: IEEE Standard for local and metropolitan
additional spectrum resources or more complex antenna area networks—Part 16: Air Interface for Fixed Broadband
schemes. Actual commercial performance will be Wireless Access Systems, 2004.
considerably less based on spectrum used and other factors. [3] IEEE Std. 802.16e: Draft IEEE std 802.16e/D9. IEEE
Standard for local andmetropolitan area networks-Part 16:
While 802.16m will provide increased performance for
Air Interface for Fixed BroadbandWireless AccessSystems.
users, the main, driving factor for operators adopting the Amendment 2: Physical and Medium Access Control
technology will be increased network capacity to Layers for Combined Fixed and Mobile Operation in
Licensed Bands, 2005.
accommodate the massive bandwidth increases driven by
[4] C. Cicconetti, L. Lenzini, E. Mingozzi, and C. Eklund,
smart phones, tablets and other wireless devices. Quality of service support in IEEE 802.16 networks, IEEE
In addition to capacity and performance advantages, Network, 8(2), March 2006.
802.16m will be backward compatible with existing [5] K. Ramadas and R. Jain, WiMAX System Evaluation
Methodology (Wimax Forum), January 2007.
WiMAX networks, providing ease-of-mind for operators [6] V. Singh and V. Sharma, Efficient and fair scheduling
deploying networks today. Most mobile WiMAX of uplink and downlink in IEEE 802.16 OFDMA
operators can easily convert from 802.16e to 802.16m by Networks, IEEE WCNC, April 2006.
[7] www.wimaxforum.org
updating some circuit plate units and software in their bases [8] T he Implications of WiMax for Competition and
stations. Regulation, OECD document [dated March 2,2006].
[9] http://electronicxtreme.blogspot.com/2006/12/wi-
14. CONCLUSION max.html [dated December 11, 2006].
It is expected that WiMAX becomes the dominant standard [10] http://news.techdirt.com/news/wirless/article/6929
for Wireless MAN networks in the world market, at least, [dated October 26,2006].
in fixed broadband networks. A brief comparison between [11] http://21talks.net/voip/voice-overwimax.
802.16 and 802.16a has been provided and also it has been [12] S. Borst, User-level performance of channel-aware
shown the advantage by using adaptive modulation. It has scheduling algorithms in wireless data networks, IEEE
been explained that the key difference between the initial Infocom, April 2003.
802.16 standard and the 802.16a consists of the
modulation scheme. The importance of OFDM has also
been analyzed and this becomes an important feature that
makes the difference between the 802.16 and 802.16a
standard. More about this topic can be found in the
literature provided. PHY and MAC layers of WiMAX have
been Discussed Future possible applications have been
discussed. WiMAX mobility standard is the next step.
However, it will have its competition too with the 802.20
standard that in short is called Mobility-Fi. We will have to
wait for the products and their performance in real
environments in order to evaluate what the standard
addresses and the real performance of these products. There
are already prototypes and also development kits using
WiMAX standard that are used for education and mainly
for research. Nowadays, there are also some products that
336 | P a g e