An Analysis of the Design and Implementation of QoS over IEEE 802 16 1 of 18 file X www docs cse574 06 ftp wimax qos index html An Analysis of the Design and Implementation of QoS over IEEE 802 16 Mark C Wood Abstract This paper gives an overview of the QoS mechanisms built into the IEEE 802 16 standard also known by the name of its vendor interoperability organization WiMAX The PHY and MAC layers of 802 16 are described in detail with regards to their QoS aspects And the relations and interactions of these QoS mechanisms are described to give an understanding of how QoS can be achieved over 802 16 This paper will also provide some factors that make 802 16 distinct in its QoS methods A comparison of the QoS mechanisms in competing technologies i e 802 11 3G will be given Also this paper will explore some of the current research being done with 802 16 on developing its QoS performance Keywords IEEE 802 16 WiMAX QoS BWA WMAN WirelessMAN multimedia networking Table of Contents 1 0 Introduction 1 1 Background 1 2 IEEE 802 16 History and Future Potential 2 0 IEEE 802 16 QoS General 2 1 The Need for QoS 2 2 IEEE 802 16 QoS Mechanisms 2 3 Adaptive Burst Profiles 3 0 IEEE 802 16 QoS Provisioning 3 1 Service Flow Classification 3 2 Dynamic Service Establishment 3 3 Two Phase Activation Model 4 0 IEEE 802 16 MAC Layer 5 0 Bandwidth Requests and Grants 5 1 Bandwidth Requests 5 2 Bandwidth Grants 6 0 Comparison with Competitor s QoS 6 1 IEEE 802 11 6 2 3G 6 3 Advantages of QoS over IEEE 802 16 7 0 Suggestions for Improvement 8 0 Summary References List of Acronyms 1 0 Introduction 5 9 2006 6 56 PM An Analysis of the Design and Implementation of QoS over IEEE 802 16 2 of 18 file X www docs cse574 06 ftp wimax qos index html 1 1 Background Wireless networking has the potential for use in broadband Internet services video and audio streaming and as an alternative to the PSTN for voice service WiMAX phones and PDAs are already being developed by companies like Motorola and Samsung And they are already in use in Korea with WiMAX s cousin technology WiBro Soon WiMAX adapters will be built into most laptops You will not have trouble finding a hot spot With WiMAX coverage everywhere will be hot There has been some struggle to popularize Broadband Wireless Access BWA Most of the delays in the use of BWA up to this point have been caused by legal or political obstructions in the US Wireless technology is being introduced rapidly in places like China and India that lack the copper wire and fiber cable infrastructures However there have been some legitimate concerns over the use of wireless in broadband networking from a technical standpoint Some of the primary concerns have been packet loss atmospheric interference and contention with other wireless services The 802 16 standard addresses these concerns with QoS In short applying more bandwidth to the right channels at the right time can reduce latency and jitter Ohrtman05 1 2 IEEE 802 16 History and Future Potential The IEEE 802 16 standard which includes MAC and PHY layer specifications was developed for Internet services over wireless metropolitan area networks WMANS and as an alternative to traditional wired networks such as DSL and cable modem 802 16 has two modes point to multipoint PMP mode and mesh mode Cao05 One of things that distinguishes 802 16 in the PHY layer is Orthogonal Frequency Division Multiplexing OFDM which is a multicarrier modulation scheme The 802 16 standard has two OFDM based modes OFDM and Orthogonal Frequency Division Multiplexing Access OFDMA Both of these technologies allow subcarriers to be adaptively modulated QPSK 16 QAM 64 QAM depending on distance and noise OFDMA also has scalability options that provide higher efficiency in bandwidth use Intel04 The MAC layer of 802 16 was originally designed for point to multipoint PMP broadband wireless access applications but later amendments of 802 16a and 802 16d also allow for mesh network architecture Ghosh05 And newly adopted in 802 16a was OFDM which provides greater spectral efficiency and better mitigation of interference 802 16b covers most of the QoS aspects of the standard 802 16TGe introduced scalable OFDMA into the standard 802 16 2004 revised and replaced previous versions and completed the essential fixed wireless standard And 802 16e was an enhancement for supporting mobile communications a handoff mechanism was added making it possible to support mobile communications at vehicular speeds A summary of the history of the 802 16 standard with regard to the QoS aspects of it is shown in Table 1 5 9 2006 6 56 PM An Analysis of the Design and Implementation of QoS over IEEE 802 16 3 of 18 file X www docs cse574 06 ftp wimax qos index html Table 1 History of IEEE 802 16 standards QoS aspects The WiMAX forum http www wimaxforum org home was formed in June of 2001 to ensure interoperability among products by different vendors And the IEEE 802 16 Working Group on Broadband Wireless Access Standards www wirelessman org is the group developing the IEEE 802 16 WirelessMAN Standard for WMANs These groups and a few others may help popularize WiMAX by bringing vendors together on it As Vint Cerf TCP IP co developer and Internet pioneer said People often take the view that standardization is the enemy of creativity But I think that standards help make creativity possible by allowing for the establishment of an infrastructure which then leads to enormous entrepreneurialism creativity and competitiveness Fast Company April 2000 A separate technology known as softswitch offers a technology bypass of the PSTN switches And 802 16 has a non line of site NLOS range of 4 miles The combination of softswitch and 802 16 as a wireless last mile makes a viable alternative to the PSTN for voice services With another technology known as TVoIP 802 16 can also serve as a cable or satellite TV bypass And with the 802 16 standard s ability to transmit 72 Mbps over 30 miles point to point it can also serve as a backhaul bypass A strong business case can be made for using WiMAX as an alternative to the telephone company s T1 and DS3 data circuits to save the enterprise the monthly local loop charges Ohrtman05 And the combination of throughput power range and versatility give 802 16 some technological advantages over competing technologies such as 802 11 and 3G There are a number of reasons both economical and technical that make it an appealing choice for broadband wireless access but the focus of
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