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Wimax (802.16)Wimax (802.16)
Presentation by:Presentation by:
P.Devendar(07S11A0406)P.Devendar(07S11A0406)
J.Sandeep(07S11A0444)J.Sandeep(07S11A0444)
P.Nageshwar rao(07S11A0419)P.Nageshwar rao(07S11A0419)
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History of WirelessHistory of Wireless
PhotophonePhotophone
audio conversations wirelessly overaudio conversations wirelessly over
modulatedmodulated light beamslight beams limited by the availability of both sunlightlimited by the availability of both sunlight
and good weatherand good weather
http://en.wikipedia.org/wiki/Light_beamhttp://en.wikipedia.org/wiki/Light_beamhttp://en.wikipedia.org/wiki/Light_beam -
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WimaxWimax
WWorldwideorldwide IInteroperability fornteroperability for
MMicrowaveicrowave AAccccessess
A certification mark for products that passA certification mark for products that passconformity and interoperability tests for the IEEEconformity and interoperability tests for the IEEE
802.16 standards802.16 standards
Run by Wimax ForumRun by Wimax Forum
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WiMAX is a wireless digital communications
system, also known as IEEE 802.16, that is
intended for wireless "metropolitan areanetworks
WiMAX can provide broadband wireless access
(BWA) up to 30 miles (50 km) for fixed stations,
and 3 - 10 miles (5 - 15 km) for mobile stations With WiMAX, WiFi-like data rates are easily
supported, but the issue of interference is
lessened. WiMAX operates on both licensed and
non-licensed frequencies, providing a regulated
environment and viable economic model for
wireless carriers.
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WiMAX is a highly scalable, long-range system,
covering many kilometers using licensed
spectrum to deliver a point-to-point connection tothe Internet from an ISP to an end user.
WiMAX can also be used to Connect many Wi-Fi
hotspots with each other and also to other parts
of the Internet.
When using WiMAX device with directional
antennas, speeds of10 Mbit/s at 10 km
distance is possible, while for WiMAX deviceswith omni-directional antennas only 10 Mbit/s
over 2 km is possible.
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WiMAX could connect remote Indian villages to
the Internet using broadband. This would avoid
hassles in cabling through the forests and otherdifficult terrain only to reach a few people in
remote places.
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WimaxWimax
Goal: Provide high-speed Internet access toGoal: Provide high-speed Internet access tohome and business subscribers, without wires.home and business subscribers, without wires.
Base stations (BS) and subscriber stations (SS)Base stations (BS) and subscriber stations (SS)
Centralized access control to prevents collisionsCentralized access control to prevents collisions
Supports applications with different QOSSupports applications with different QOSrequirementsrequirements
WiMAX is a subset of IEEE 802.16 standardWiMAX is a subset of IEEE 802.16 standard
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IEEE 802.16 standardsIEEE 802.16 standards
802.16.1 (10-66 GHz, line-of-sight, up to802.16.1 (10-66 GHz, line-of-sight, up to134Mbit/s)134Mbit/s)
802.16.2 (minimizing interference between802.16.2 (minimizing interference between
coexisting WMANs)coexisting WMANs)
802.16a (2-11 Ghz, Mesh, non-line-of-sight)802.16a (2-11 Ghz, Mesh, non-line-of-sight)
802.16b (5-6 Ghz)802.16b (5-6 Ghz) 802.16c (detailed system profiles)802.16c (detailed system profiles)
P802.16e (Mobile Wireless MAN)P802.16e (Mobile Wireless MAN)
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Physical layerPhysical layer
Allows use of directional antennasAllows use of directional antennas Allows use of two different duplexing schemes:Allows use of two different duplexing schemes:
Frequency Division Duplexing (FDD)Frequency Division Duplexing (FDD)
Time Division Duplexing (TDD)Time Division Duplexing (TDD)
Support for both full and half duplex stationsSupport for both full and half duplex stations
Adaptive Data Burst profilesAdaptive Data Burst profiles Transmission parameters (e.g. Modulation, FEC) canTransmission parameters (e.g. Modulation, FEC) can
be modified on a frame-by-frame basis for each SSbe modified on a frame-by-frame basis for each SS Profiles are identified by Interval Usage CodeProfiles are identified by Interval Usage Code
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Time Division Duplexing (TDD)Time Division Duplexing (TDD)
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TDD Downlink subframeTDD Downlink subframe
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Uplink subframeUplink subframe
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Bandwidth requestBandwidth request
SSs may request bandwidth in 3 ways:SSs may request bandwidth in 3 ways:Use the contention request opportunitiesUse the contention request opportunities
interval upon being polled by the BSinterval upon being polled by the BS
Send a standalone MAC message called BWSend a standalone MAC message called BW
request in an allready granted slotrequest in an allready granted slot
Piggyback a BW request message on a dataPiggyback a BW request message on a data
packetpacket
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PLANPLAN
I Transmission of the dataI Transmission of the data
II ARQII ARQ
III SchedulingIII Scheduling
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MacMac and physicaland physical layerlayerss
II ARQII ARQ
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II ARQII ARQ
A ARQA ARQ1.1. Stop and WaitStop and Wait
2.2. Sliding window techniqueSliding window technique
3.3. Feedback ( go back-N)Feedback ( go back-N)
4.4. Selective repeatSelective repeat
B FECB FEC
C H-ARQC H-ARQ
D Methods used by WIMAXD Methods used by WIMAX
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Stop and WaitStop and Wait
Transmitting
Data
1 32 3Time
Received Data 1 2 3 Time
ACK
ACK
NAK
Output Data 1 2 3 Time
Error
ACK: Acknowledge
NAK: Negative ACK
retransmission
II ARQII ARQ
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II ARQII ARQ
A ARQA ARQ1.1. Stop and WaitStop and Wait
2.2. Sliding window techniqueSliding window technique
3.3. Feedback ( go back-N)Feedback ( go back-N)
4.4. Selective repeatSelective repeat
B FECB FEC
C H-ARQC H-ARQ
D Methods used by WIMAXD Methods used by WIMAX
II ARQII ARQ
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II ARQII ARQ
The sliding window techniqueThe sliding window technique
Without window With a sliding windowWithout window With a sliding windowsize=0 (stop and wait) size=3size=0 (stop and wait) size=3
Tran
sm
itte
r
Rec
ep
tor
Tran
sm
itte
r
Recep
tor
II ARQII ARQ
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II ARQII ARQ
A ARQA ARQ1.1. Stop and WaitStop and Wait
2.2. Sliding window techniqueSliding window technique
3.3. Feedback ( go back-N)Feedback ( go back-N)
4.4. Selective repeatSelective repeat
B FECB FEC
C H-ARQC H-ARQ
D Methods used by WIMAXD Methods used by WIMAX
F db k ( b k N)
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Feedback ( go back-N)Feedback ( go back-N)
1Time
NAK
Time
Error
Go-back 3
2 3 4 5 3 44 5 6 7 5
1 2 3 44 5
Error
NAK
Go-back 5
1 2 3 44 5
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Selective repeatSelective repeat
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Selective repeatSelective repeat
1Time
NAK
Error
Retransmission
2 3 4 5 3 6 7 8 9 7
1 Time2 4 3 6 8 7Error
NAK
Retransmission
5 9
1Time
2 4 3 6 8 75 9
1Time
2 43 6 875 9
II ARQII ARQ
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II ARQII ARQ
A ARQA ARQ1.1. Stop and WaitStop and Wait
2.2. Sliding window techniqueSliding window technique
3.3. Feedback ( go back-N)Feedback ( go back-N)
4.4. Selective repeatSelective repeat
B FECB FEC
C H-ARQC H-ARQ
DD Methods used by WIMAXMethods used by WIMAX
FECFEC
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FECFEC
II ARQII ARQ
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II ARQII ARQ
A ARQA ARQ1.1. Stop and WaitStop and Wait
2.2. Sliding window techniqueSliding window technique
3.3. Feedback ( go back-N)Feedback ( go back-N)
4.4. Selective repeatSelective repeat
B FECB FEC
C H-ARQC H-ARQ
DD Methods used by WIMAXMethods used by WIMAX
H-ARQH-ARQ
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H-ARQH-ARQ
H-ARQ= FEC+ARQH-ARQ= FEC+ARQ
FEC: turbo codes/ convolution codes/ blockFEC: turbo codes/ convolution codes/ block
codes/codes/
ARQ: selective repeat (SR) / stop and waitARQ: selective repeat (SR) / stop and wait
(SAW)/ go-back-N (GBN)(SAW)/ go-back-N (GBN)
II ARQII ARQ
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II ARQII ARQ
A ARQA ARQ1.1. Stop and WaitStop and Wait
2.2. Sliding window techniqueSliding window technique
3.3. Feedback ( go back-N)Feedback ( go back-N)
4.4. Selective repeatSelective repeat
B FECB FEC
C H-ARQC H-ARQ
D Methods used by WIMAXD Methods used by WIMAX
Methods used by WIMAXMethods used by WIMAX
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Methods used by WIMAXMethods used by WIMAX
ARQ mechanism is an optional part of theMAC layer in WIMAX.
WIMAX can use ARQ ,FEC or H-ARQ.
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SchedulingScheduling
Radio resources have to be scheduled according toRadio resources have to be scheduled according tothe QOS (Quality of Service) parametersthe QOS (Quality of Service) parameters
WIMAX Downlink scheduling:WIMAX Downlink scheduling:
the flows are simply multiplexedthe flows are simply multiplexed the standard scheduling algorithms can be used :the standard scheduling algorithms can be used :
WRR (Weighted Round Robin)WRR (Weighted Round Robin)VT (Virtual Time)VT (Virtual Time)
WFQ (Weighted Fair Queuing)WFQ (Weighted Fair Queuing)WFFQ (Worst-case Fair weighted Fair Queuing)WFFQ (Worst-case Fair weighted Fair Queuing)DRR (Deficit Round Robin)DRR (Deficit Round Robin)DDRR (Distributed Deficit Round Robin)DDRR (Distributed Deficit Round Robin)
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ConclusionConclusion
Framework for the evolution of wirelessFramework for the evolution of wireless
broadbandbroadband
Everything will be coordinated with WimaxEverything will be coordinated with Wimax
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Queries???