WIMAX

WIMAX NETWORK ANALYSISOPNET SIMULATOR

Presented by:

Selem Trabelsi

proposed by :Mr MNIF KAIS

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Description of WIMAX

OPNET Modeler simulator

implementation and results

Conclusion

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Conclusion

Introduction

In this project our purpose is to test the transfer efficiency WiMAX network by using the OPNET modeler software.

The goal: • Simulate WIMAX with the software OPNET Modeler• to know the basic actions for the simulation, •use interfaces and libraries located in OPNET models•The environment allows OPNET modeling and simulation networks communication with its model libraries (routers, switches, stations workstations, servers ...) and protocols (TCP / IP, FTP,).

WiMAX ( Worldwide Interoperability for Microwave Access) is a standard wireless communication. Today mostly used mode of transmission and high-speed Internet access, on a large geographical area.

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Introduction1

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objectives:provide a broadband internet connection on a coverage area of several

kilometers. In theory: 74 Mbit / s with a range of 50 km

Operation:• WiMAX operates with a principle of the base station, a central unit

which is connected to the antennas of the subscribers. • Supports applications with different QoS requirements• 2 types of application:

Fixed 802.16dMobile 802.16e

Limits:The rate decreases with the presence of obstacles LOS (line of sight: the presence of obstacles) NLOS (Non line of sight: no presence of obstacles).The actual flow in the presence of obstacles and can not exceed 20 Mbit / s.

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designation frequency LoS/NLoS Options multiplexing

SC 10-66Ghz LoS TDD,FDD

SCa 2,5-11Ghz NLoS AAS, ARQ, STC TDD,FDD

OFDM 2,5-11Ghz NLoS AAS, ARQ, STC, mesh

TDD,FDD

OFDMA 2,5-11Ghz NLoS AAS, ARQ, STC TDD,FDD

Wireless-HUMAN 2,5-11Ghz NLoS ARQ, STC, Mesh TDD

physical Layer

OFDM Processing allows 256 points of transformation Only One user in symbol OFDM

OFDMA Up to 2048 points of transformation uses the principle of OFDM but allocates frequencies to more than one user.Wireless-HUMAN use of unlicensed frequency 3

Scheduling services

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Introduction1

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OPNET MODELER simulator

OPNET modeler enable solutions :Test technology designs in realistic scenariosEvaluate enhancements to standards-based protocolsDevelop new protocols and technologies

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OPNET modeler simulator

OPNET supports many simulation technologies:

•Discrete Event Simulation (DES)provides highly detailed models that explicitly simulate packets and protocol messages The model in DES execute the protocol in much the same way as a production environmentAlthough DES provides high results, simulation runtimes are longer than with the other methods

•Flow AnalysisFlow Analysis does not model individual protocol messages or packets,therefore it does not generate results for transient network conditionsIt can be used to study routing and reachability across the network insteady state, and in scenarios with one or more failed devicesExecution runtimes can be signicantly faster as compared with DES

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Introduction1

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Scenario 1: comparison between WIMAX_WLAN

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Scenario 1: comparison between WIMAX_WLAN

•Base Station(OFDM)• Subscriber Wimax_Wlan (11 Mbps)•Server •3 Wlan Station (nrtps) •Station 1 silver (nrtps)•Minimum reserved traffic rate=2000 bps•Duration of simulation = 20 mn•the server sends traffic to all stations traffic for station 1 at 2 mn•Analyze only the traffic to station 1

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scenario 1:analyze and interpret the results

this curve shows the throughput between the base station and SS wimax _wlan minimun throughput=2900 bit/smaximun throughput=5800 bit/sAverage throughput=4500 bit/s

this curve shows the throughput between the SS wimax _wlan and Station 1 minimun throughput=120 bytes/s =960 bit/smaximun throughput=230 bytes/s=1840 bit/sAverage throughput=150 bytes/s=1200 bit/s 9


•the variation of throughput in both of the wimax and wlan network is explained by the availability of bandwidth (shared resource)

•we note that the throughput in WiMAX network is always superior to 2000 bit / s because nrtps requires a minimum rate equal to 2000/s

•The throughput between the WiMAX Base Station and a WLAN-WiMAX router is higher than the throughput in WLAN network

•Wimax is more efficient than WLAN

•In the Wlan network the throughput is low because there are many stations that use bandwidth

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Four SS nodes are configured in the network with a different service class:UGS_ss: (Gold class ,UGS Scheduling, minimum rate=16.8 Mbps)silver_A_ss: (Silver_A class,rtPS Scheduling , minimum rate=2.0 Mbps)

silver_B_ss:(Silver_B class ,rtPS Scheduling ,minimum rate 0.5 Mbpsdefault_ss: (System Default ,BE,0.0 Mbps)

Scenario 2:interaction with different QoS Scheduling services

•Duration of simulation =15 mn•BE traffic starts at 2 mn•Silver_B traffic starts at 2mn ends at 10 mn•Silver_A starts at 5mn ends at 7.5 mn•No traffic for UGS

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•Traffic send to BS (bandwith max =3 Mb/s)•Between (2 5 mn) and (7.5 10 mn) 2 traffic available both are served Average thoughput for silver B =2.5 Mb/s and 0.5 for BE•Between 5 and 7.5 mn 3 traffic only rtps traffic is served•Average throughput for silver A =2.0 Mbps and 0.9 Mb/s for silver B•After t=10 mn only BE traffic with average throughput =1.2 Mb/s 12

•UGS_ss has no traffic activity. It is used to limit the resources available for polling and best effort services.

•Rtps is prioritized than BE

•BS scheduler served silver A on the first because it requires more rate than silver B

•Both silver SSs are serviced by the BS scheduler based on their weights (80 to 20), using the available bandwidth.

•The default SS uses the System Default class, which provides no service guarantees, then it will use resources left available (if any) by the rtPS services.


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•The scenario contains 3 mobile stations, use different MCS schemes.•one uses QPSK 1/2 •one uses Adaptive•one uses 64QAM 3/4

Scenario 3: using Adaptive Modulation and Coding

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•the variation of signal quality is explained by the mobility of SS and the interference between signal•the number of bits per symbol in 64 QAM ¾ equal 5•(5 for transmission data and 1 bit for CRC (error control)•the number of bits per symbol in QPSK ½ equal 1 bit for data •In AMC the number of bits per symbol varies max =5 min =1 15

•The lower throughput its by using 64 QAM ¾ because there are more lost packet with this MCS •64 QAM ¾ is effective when the signal quality is high but it isn’t robust to errors•64-QAM, better signal-to-noise ratios (SNRs) are needed to overcome any interference and maintain a certain bit error ratio (BER).•QPSK modulation is more robust and gives excellent throughput.


•The use of adaptive modulation allows a wireless system to choose the highest order modulation depending on the signal quality.• adaptive modulation allows the system to overcome fading and interference. 16

Introduction1

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Conclusion

OPNET is a powerful software which allows many models of networksthanks to its many libraries. This makes the software requires a good knowledge and understanding of the field of networks to control the ins and outs of the software.

Moreover, OPNET seems by its complexity and many setting options requires proper training to be fully controlled.

this software offers a story mode and features (modeling,simulation, ...) it would be interesting to use in the practical work.

Conclusion

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MERCI POUR VOTRE ATTENTION

WIMAX

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Transcript of WIMAX