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Transcript of Shashi,
WIMAXWIMAX
BY
SHASHI JAKKU
Contents Introduction Working of WIMAX IEEE 802.16 standard 802.16 Architecture IEEE 802.16 Specifications Features of WIMAX Advantages of WIMAX over WIFI WIMAX vs. 3G ISSUES in WIMAX vs. 3G FUTURE OF WIMAX
What is WIMAX?
WIMAX stands for Worldwide Interoperability for Microwave Access
WiMAX refers to broadband wireless networks that are based on the IEEE 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.
THINK OF INTERNET There are three possible ways to
access internet. Broadband access
Uses DSL or cable modem at home and T1 or T3 line at office
WIFIUses WIFI routers at home and hotspots on the road
Dial Up Connection
NEW TECHNOLOGY
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
1) A WiMAX tower, similar in concept to a cell-phone tower - A single WiMAX tower can provide coverage to a very large area
as big as 3,000 square miles (~8,000 square km). 2) 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
A WIMAX system consists of
WIMAX TOWER WIMAX RECEIVER
HOW WIMAX works?
MODES OF OPERATION
Non-Line of sightUses a lower frequency range.
Line of sightUses a higher frequency range.
WIMAX Scenario Consider a scenario where a WiMax-enabled computer is
10 miles away from the WiMax base station.
A special encryption code is given to computer to gain access to base station
The base station would beam data from the Internet required for computer (at speeds potentially higher than today's cable modems)
WIMAX Scenario The user would pay the provider monthly fee for using
the service. The cost for this service could be much lower than current high-speed Internet-subscription fees because the provider never had to run cables
The WiMAX protocol is designed to accommodate several different methods of data transmission, one of which is Voice Over Internet Protocol (VoIP)
If WiMAX-compatible computers become very common, the use of VoIP could increase dramatically. Almost anyone with a laptop could make VoIP calls
WIMAX CHIPS
WiMAX Mini-PCI Reference Design Intel’s first WIMAX chip
IEEE 802.16
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
IEEE 802.16 Specifications 802.16a
Uses the licensed frequencies from 2 to 11 GHzSupports Mesh network
802.16b Increase spectrum to 5 and 6 GHzProvides QoS( for real time voice and video service)
802.16c Represents a 10 to 66GHz
802.16d Improvement and fixes for 802.16a
802.16eAddresses on MobileEnable high-speed signal handoffs necessary for
communications with users moving at vehicular speeds
802.16 Architecture IEEE 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.
802.16 Architecture
P2MP ArchitectureBS connected to Public Networks
BS serves Subscriber Stations (SS)Provides SS with first mile access to Public
Networks
Mesh ArchitectureOptional architecture for WiMAX
P2MP Architecture
Mesh Architecture
FEATURES OF WIMAX
Scalability
Quality of Service
Range
Coverage
Scalability The 802.16 standard supports flexible radio
frequency (RF) channel bandwidths.
The standard supports hundreds or even thousands of users within one RF channel
As the number of subscribers grow the spectrum can be reallocated with process of sectoring.
Quality of Service 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.
Requirements for QoS A configuration and registration function to pre
configure SS based QoS service flows and traffic parameters
A signalling function for dynamically establishing QoS enabled service flows and traffic parameters
Utilization of MAC scheduling and QoS traffic parameters for uplink service flows
Utilization of QoS traffic parameters for downlink service flows
RANGE
Optimized for up to 50 Km Designed to handle many users
spread out over kilometres Designed to tolerate greater multi-
path delay spread (signal reflections) up to 10.0μ seconds
PHY and MAC designed with multi-mile range in mind
Coverage
Standard supports mesh network topology
Optimized for outdoor NLOS performance
Standard supports advanced antenna techniques
BENEFITS OF WIMAX
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
Benefits to Service Providers 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
Benefits to Customers
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
Why not WIFI
Scalability Relative Performance Quality of Service Range Coverage Security
Scalability
• 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
• MAC designed to support thousands of users.
• Wide (20MHz) frequency channels
• MAC designed to support 10’s of users
802.16a802.11
5.0 bps/Hz100 Mbps1.5 – 20 MHz802.16a
2.7 bps/Hz54 Mbps20 MHz802.11
Maximum bps/Hz
Maximum Data Rate
Channel Bandwidth
RELATIVE PERFORMANCE
Quality of Service
• Grant-request MAC
• Designed to support Voice and Video from ground up
• Supports differentiated service levels: e.g. T1 for business customers; best effort for residential.
• Centrally-enforced QoS
• Contention-based MAC (CSMA/CA) => no guaranteed QoS
• Standard cannot currently guarantee latency for Voice, Video
• Standard does not allow for differentiated levels of service on a per-user basis
• 802.11e (proposed) QoS is prioritization only
802.16a802.11
Range
• 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 10.0μ seconds
• PHY and MAC designed with multi-mile range in mind
• Optimized for ~100 meters
• No “near-far” compensation
• Designed to handle indoor multi-path delay spread of 0.8μ seconds
• Optimization centers around PHY and MAC layer for 100m range
802.16a802.11
Coverage
• Optimized for outdoor NLOS performance
• Standard supports mesh network topology
• Standard supports advanced antenna techniques
• Optimized for indoor performance
• No mesh topology support within ratified standards
802.16a802.11
Security
• Existing standard is PKM - EAP• Existing standard is WPA + WEP
• 802.11i in process of addressing security
802.16a802.11
Advantages of WiMax over 3G
Using an assortment of proprietary and standards-based technologies, such as OFDM and W-CDMA ,WiMax has a clear advantage over 3G
The advantages include Higher Throughput Low Cost Lower Latency
Advantages of WiMax over 3G
Advantages of WiMax over 3G
WiMax spectrum is more economical than 3G. The price paid per Hz is as much as 1000
times lower than for 3G spectrum
The low cost is a clear driver for service providers to enter the field of wireless services with WiMax
Advantages of WiMax over 3G WiMAX is important for mobile broadband
wireless, as it completes 3G by providing higher performance for data with more than 1 Mbps downstream to allow connection of laptops and PDAs
WiMAX technology is the solution for many types of high-bandwidth applications at the same time across long distances and will enable service carriers to converge the all-IP-based network for triple-play services data, voice, and video
Advantages of WiMax over 3G WiMAX interoperable solutions enable
economies of scale through integration of standard chipsets, making WiMAX Forum Certified products cost-effective at delivering high-capacity broadband services at large coverage distances in Line Of Sight and Non Line Of Sight conditions
USES OF WIMAX
More ……
FUTURE
WiMax will be deployed in three stages In the first phase WiMaX technology (based on IEEE
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 IEEE 802.16e) will be integrated into commercial laptops
Promises
ISSUES in 3G vs. WIMAX
Deployment of the network WIMAX deployment is in the planning
stages and it might take 3-5 years in providing reasonable coverage in well populated areas
WiMax may initially be relegated to college campuses and larger corporate campuses where people are less mobile and costs containment is important
ISSUES in 3G vs. WIMAX
Quality of Service To provide quality of service by deploying WIMAX
networks and to facilitate the continuous availability of service, careful planning is required at the edge of the network to manage network monitoring, availability, failover, routing etc
This can actually be done using outsourced services in cheap labor markets like India and China via the
public Internet
ISSUES in 3G vs. WIMAX
Cost Issue The main reason to opt for WIMAX is its low cost.
The price paid per Hz for WIMAX spectrum is as much as 1000 times lower than for 3G spectrum
The low cost of WIMAX spectrum compared to 3G is a clear driver for service providers to enter the field of
wireless services with WIMAX
The WIMAX Forum Founded in April 2001
No Profit organization comprised of wireless access system manufacturers, component suppliers, software developers and carriers
A wireless industry consortium that supports and promotes WiMAX’s commercial usage
Comply with the WiMAX standard and focus on the interoperability
Members include Intel, AT&T, Siemens Mobile, British Telecommunications, etc
Conclusion (The Final Issue) 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
References www.ewh.ieee.org/r4/chicago/Yu-WiMAX.pdf
http://computer.howstuffworks.com/wimax.htm
www.wimaxforum.org
http://standards.ieee.org/catalog/olis/lanman.html
Questions?