10-06-2017, 07:06 AM
Introduction Working of WIMAX IEE 802.16 standard 802.16 Architecture Features of WIMAX Advantages of WIMAX over WIFI FUTURE OF WIMAX There are three possible ways to access internet. Broadband access Uses DSL or cable modem at home and T1 or T3 line at office WIFI Uses WIFI routers at home and hotspots on the road Dial Up Connection Broadband access is too expensive and WiFi coverage is very sparse. The new technology promises High speed of broadband service Wireless rather than wired access Broad Coverage WIMAX stands for Worldwide Interoperability for Microwave Access WiMAX refers to broadband wireless networks that are based on the IEE 802.16 standard, which ensures compatibility and interoperability between broadband wireless access equipment WiMAX, which will have a range of up to 31 miles, is primarily aimed at making broadband network access widely available without the expense of stringing wires (as in cable-access broadband) or the distance limitations of Digital Subscriber Line. A WiMAX tower, similar in concept to a cellphone tower - A single WiMAX tower can provide coverage to a very large area as big as 3,000 square miles ( 8,000 square km). A WiMAX receiver - The receiver and antenna could be a small box or Personal Computer Memory card, or they could be built into a laptop the way WiFi access is today Non-Line of sight Uses a lower frequency range. Line of sight Uses a higher frequency range. WiMAX Mini-PCI Reference Design Intel s first WIMAX chip Range- 30 miles from base station Speed- 70 Megabits per second Frequency bands- 2 to 11 and 10 to 66(licensed and unlicensed bands respectively) Defines both MAC and PHY layer and allows multiple PHY layer specifications IEE 802.16 Protocol Architecture has 4 layers: Convergence, MAC, Transmission and physical, which can be mapped to two OSI lowest layers: physical and data link. Scalability Quality of Service Range Coverage Primary purpose of QoS feature is to define transmission ordering and scheduling on the air interface These features often need to work in conjunction with mechanisms beyond the air interface in order to provide end to end QoS or to police the behaviour or SS. It provides flexible and dynamic QoS . Speed Faster than broadband service Wireless Not having to lay cables reduces cost Easier to extend to suburban and rural areas Broad Coverage Much wider coverage than WiFi hotspots Allow service providers to deliver high throughput broadband based services like VoIP, high-speed Internet and Video Facilitate equipment compatibility Reduce the capital expenditures required for network expansion Provide improved performance and extended range Range of technology and service level choices from both fixed and wireless broadband operators DSL-like services at DSL prices but with portability Rapidly declining fixed broadband prices No more DSL installation fees from incumbent Scalability Relative Performance Quality of Service Range Coverage Security 802.11 802.16a Channel bandwidths can be chosen by operator (e.g. for sectorization) 1.5 MHz to 20 MHz width channels. MAC designed for scalability. independent of channel bandwidth Wide (20MHz) frequency channels MAC designed to support 10 s of users MAC designed to support thousands of users. Channel Bandwidth 802.11 802.16a 20 MHz 1.5 20 MHz Maximum Data Rate 54 Mbps 100 Mbps Maximum bps/Hz 2.7 bps/Hz 5.0 bps/Hz 802.11 802.16a Standard cannot currently Designed to support Voice and guarantee latency for Voice, Video Video from ground up Standard does not allow for differentiated levels of service on a per-user basis Supports differentiated service levels: e.g. T1 for business customers; best effort for residential. 802.11 802.16a Optimized for 100 meters No near-far compensation Optimized for up to 50 Km Designed to handle many users spread out over kilometers Designed to tolerate greater multi-path delay spread (signal reflections) up to 10.0 seconds PHY and MAC designed with multi-mile range in mind Designed to handle indoor multipath delay spread of 0.8 seconds Optimization centers around PHY and MAC layer for 100m range 802.11 802.16a Optimized for indoor performance Optimized for outdoor NLOS performance Standard supports mesh network topology Standard supports advanced antenna techniques No mesh topology support within ratified standards 802.11 802.16a Existing standard is WPA + WEP Existing standard is PKM EAP Encryption codes are used WiMax will be deployed in three stages In the first phase WiMaX technology (based on IEE 802.16-2004) provides fixed wireless connections In the second phase WiMaX will be available as a cheap and self-installing Subscriber Terminal (ST), linked to PC and to antenna The third phase enables portability, thus WiMAX (based on IEE 802.16e) will be integrated into commercial laptops Will WIMAX replace 3G Along with the forthcoming standardization, WiMAX has the potential to substitute 3G and become a promising 4G WiMAX has its distinct identity as either a stand-alone solution for incumbent and competitive fixed network operators or as complementary radio access solution for established 2G and 3G cellular network operators Fixed-line operators, on the one hand, may consider WiMAX as a viable alternative to add mobility to the service portfolio, leveraging their huge subscriber base, in particular in countries where 3G licensing is delayed or not affordable