Wi max vs wifi

WiMAX Vs Wi-Fi

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WiMAX

Worldwide Interoperability for Microwave Access Brand licensed by the WiMax Forum. “a standards-based technology enabling the delivery of

last mile wireless broadband access as an alternative to cable and DSL”

WiMAX was seen as more of a Metropolitan Area Network (MAN) technology providing a much larger coverage.

Based on IEEE 802.16

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WiMAX

WiMAX, in fact, comes in two forms, a so called ‘fixed WiMAX’ and a ‘mobile WiMAX’.

WiMAX in its fixed form is seen as a possible alternative to expensive cable and fibre deployment.

It is faster to deploy and less expensive and it also offers operators more flexibility in terms of deployment time frame and possible installation areas.

3G or other cellular network operators could see this as a potential substitute or as a complement to their cellular product.

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WiMAX Architecture

MIB – Management Information Base

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Wi-Fi

Stands for Wireless Fidelity. Brand licensed by the Wi-Fi Alliance. Wi-Fi is a local area network technology that was

originally thought to replace the thousands of miles of LAN cables.

Wireless Local Area Networks (WLAN) Based on IEEE 802.11

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Wi-Fi Wi-Fi has grown from being just a LAN cable

replacement technology to a public wireless access technology.

Cheap and readily available equipment.

WiFi has been viewed as complementary to 3G and other mobile standards as it has worked to enhance mobile services offered by operators.

It’s coverage is not as great as that of 3G, but it gives a much higher transmission rate than mobile technology.

Handoff between WiFi access points is still not possible and, therefore, it is known more as a wireless access technology than a mobile technology.

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New developments are taking place within the 802.11 standardization group

With the increasing popularity of VoIP, many see WiFi as one of the possible means of using VoIP with some form of mobility

802.11r for wireless VoIP and other real time applications

802.11s for meshed WiFi networking

Making WiFi more mobile could make it more of a substitute to mobile technologies

Wi-Fi

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Wireless Systems

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802.11 Protocol Stack

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802.16 protocol stack

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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, fixed (20MHz) frequency channels

MAC designed to support 10’s of users

802.16802.11

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Bit Rate: Relative Performance

802.16a ~5.0 bps/Hz

~2.7 bps/Hz54 Mbps20 MHz

63 Mbps*10, 20 MHz;

1.75, 3.5, 7, 14 MHz;3, 6 MHz

802.11a

ChannelBandwidth

Maximumbps/Hz

MaximumData Rate

* Assuming a 14 MHz channel

802.16a is designed for metropolitan performance

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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

802.16802.11

Coverage

802.16 is designed for market coverage

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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

StandardMAC;Sectoring/MIMO/AMC for Rate/Range dynamic tradeoff

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.

Range can be extended by cranking up the power – but MAC may be non-standard.

802.16802.11

Range

802.16 is designed for distance

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Quality of Service (QoS)

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.

TDD/FDD/HFDD – symmetric or asymmetric

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

TDD only – asymmetric

802.11e (proposed) QoS is prioritization only

802.16a802.11

802.16a is designed for carrier class operation

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Triple-DES (128-bit) and RSA (1024-bit)

Existing standard is WPA + WEP

802.11i in process of addressing security

802.16a802.11

Security

802.16a maintains fixed wireless security

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WiMAX vs Wi-Fi

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WiMAX vs Wi-Fi

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Comparison of WiMAX, WiFi and 3G technology

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802.11 and 802.16 both gain broader industry acceptance through conformance and interoperability by multiple vendors

802.16 complements 802.11 by creating a complete MAN-LAN solution

802.11 is optimized for license-exempt LAN operation

802.16 is optimized for license-exempt and licensed MAN operation.

802.11 vs 802.16: Summary

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Will WiMAX displace WiFi? WiMAX will not replace

WiFi completely, but work TOGETHER

Intel is currently integrating WiMAX and WiFi into a single Centrino chip.

WiFi’s primary role will always be autonomous hotspot service

areas (indoor and outdoor 0 ft. < cell radii <500 ft.).

WiMax will ultimately replace WiFi in large-scale (greater than 1mi.Sq.) commercial and public roles.

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Wi-fi and WiMax Together