Determination of optimum fft for wi max under different fading

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Determination of optimum fft for wi max under different fading

  1. 1. International Journal of Electronics and JOURNAL Engineering & Technology (IJECET), ISSN 0976 INTERNATIONAL Communication OF ELECTRONICS AND– 6464(Print), ISSN 0976 – 6472(Online) Volume 3, Issue 1, January- June (2012), © IAEME COMMUNICATION ENGINEERING & TECHNOLOGY (IJECET)ISSN 0976 – 6464(Print)ISSN 0976 – 6472(Online)Volume 3, Issue 1, January- June (2012), pp. 139-146 IJECET© IAEME: www.iaeme.com/ijecet.htmlJournal Impact Factor (2011): 0.8500 (Calculated by GISI) ©IAEMEwww.jifactor.com DETERMINATION OF OPTIMUM FFT FOR WI-MAX UNDER DIFFERENT FADING Abhishek choubey HOD,ECE deptt. R.K.D.F. Bhopal abhishekchaubey84@gmail.com Mayuri Kulshreshtha M.E (D.C.) R.K.D.F. Bhopal mayuri.kulsh@gmail.com Karunesh M.Tech (Electronics Engg.) Allahabad University karunesh.ec@gmail.comABSTRACTHere we are using Worldwide Interoperability for Microwave Access (WiMAX)technology with focus on Quality of Service (QoS). The basics of the technologies for thephysical layer and the Media Access Control (MAC) layer are introduced. Here in thispaper an area-efficient FFT processor is proposed for IEEE 802.16 Wi-MAX systems.The proposed scalable FFT processor can support the variable length of 2048, 1024, 512and 128. And we are taking various data rates as 200 Kbps, 400Kbps, 600 Kbps,800Kbps and 1000 Kbps to find the Quality of service and the trade off index to findwhich FFT size is suitable for wi-max system at different channel propertiesHere the simulator which we are using in our work is qualnet simulator version 5.1. Asthe main aim of wi-max is to provide the best quality of service so here we’ll find theQoS at different scenarios based on the values of FFT and by applying the different datarates and also we are using heterogeneous network to simulate QoS and we are also usingCBR which is traffic generator application layer protocol used to generate traffic atconstant bit rate.Keywords: Wi-Max, IEEE 802.16, Qualnet simulator, FFT. 139
  2. 2. International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN 0976– 6464(Print), ISSN 0976 – 6472(Online) Volume 3, Issue 1, January- June (2012), © IAEMEI. INTRODUCTIONWiMAX is a telecommunication protocol that provides fixed and mobile internet access,in which this protocol combines a number of wireless technologies that have emergedfrom IEEE to face the rapid demand of higher data rate and longer transmission range inwireless access and to enable a high speed connection to the Internet in terms ofmultimedia service, trade, commerce, education, research and other applications. In otherhand, WiMAX technology based on IEEE 802.16 standard which is a BroadbandWireless Access (BWA) that offers mobile broadband connectivity. Here first of all weare defining wi-max architecture and then the simulation model for which we want tosimulate our result. Here we are simulating our result using two fading techniques such asRayleigh fading and the Racian fading.We are taking four FFT values as 2048, 1024, 512 and 128 and the data rates are 200Kbps, 400 kbps, 600 Kbps, 800Kbps so that we can find on which value of FFT and datarate we’ll get the best TOI. TOI is trade off index which is used to simulating the bestresults among them. We are also using CBR which generates the constant traffic and it isthe application layer protocol. Result will be described in our next section.II. WI-MAX SIMULATION MODELThe purpose of this simulation study is to investigate and evaluate different types ofscenarios in order to determine the one that is most efficient in WiMAX network. Thesimulations are performed using QualNet simulation. This simulation provides anintuitive model set up capability that includes packet delivery ratio, average jitter,average end to end delay and throughput.Here we are taking two base stations and 20 are the subscriber station. Cloud icon is usedas wireless subnet and we’ll change the property of physical layer and MAC layer inwireless subnet and base stations as we want to simulate our result using Wi-max.We are simulating QoS without fading, with Rayleigh fading and with Racian fading.The FFT values vary from 2048 to 128 and data rates varies from 200 Kbps to 1000Kbps. 140
  3. 3. International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN 0976– 6464(Print), ISSN 0976 – 6472(Online) Volume 3, Issue 1, January- June (2012), © IAEMEFrequency band (GHz) 2.4Channel bandwidth (MHz) 20FFT size 2048-128Number of MS 11-22Number of BS 2BS transmit power 20 p_t dB m/ height (m)MS transmit power 15 p_t dB m/ height (m)Services types (QoS) Packet delivery ratio, delay, jitter, throughputData rates (Kbps) 200-1000Simulation time 30sIII. PERFORMANCE EVALUATIONHere we are taking different channel properties for simulating the best result. Firstly weare simulating result with Rayleigh fading.Quality of service with Rayleigh fadingHere we’ll find the QoS in terms of packet delivery ratio, average end to end delay,average jitter and throughput. First of all we are taking channel property as Rayleighfading, the graphs for all the services will be shown as- Graph 4.1 Packet Delivery ratioGraph 4.1 is the graph of packet delivery ratio, which is the ratio of the received packetsand the transmitted packets. At X-axis we are taking different data rates as 200 Kbps, 400Kbps, 600 Kbps, 800 Kbps and the 1000 Kbps. We are also taking the values of FFT as2048, 1024, 512 and 128 at Y-axis. Here we can see at all the three values of FFT alllines are about same but at 2048 FFT the values of packet delivery ratio is changed.different data rates all the points are changed, so from the above graph we can see there isno affect of FFT for packet delivery ratio but at different data rates the value of packetdelivery ratio is changed. As we are increasing data rates the packet delivery ratio isdecreasing it means at higher data rates less amount of packets are receiving at thedestination. 141
  4. 4. International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN 0976– 6464(Print), ISSN 0976 – 6472(Online) Volume 3, Issue 1, January- June (2012), © IAEME Graph 4.2 Average jitterGraph 4.2 is the graph of average jitter. As we know Jitter is the variation in arrival timesof successive packet from a source to a destination. Here we can see when we arechanging the values of FFT there is little effect on jitter, but with increasing the data ratesjitter is decreasing continuously. So we can say jitter is inversely proportional to datarate, it means at increasing data rates jitter is decreasing. Graph 4.3 average delayGraph 4.3 is the graph of average delay. Here we can see at FFT value of 2048 and 1024with all data rate values except 1000 Kbps the delay is about to same or we can say aboutto constant, it means there is little delay with FFT 2048 and 1024. When we talk aboutthe FFT value 512, the delay is increasing with increasing data rate. But at 128 FFT delayis increased at some values of data rates and after then it is continuous for other datarates. Graph 4.4 ThroughputGraph 4.4 is the graph of throughput. Throughput is defined as how much data isaccepted at the receiver. Here we can see throughput is increasing with increasing Data 142
  5. 5. International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN 0976– 6464(Print), ISSN 0976 – 6472(Online) Volume 3, Issue 1, January- June (2012), © IAEMErate, it means throughput is ditrectly proportional to data rates. But when we talk aboutFFT there is little effect of FFT at throughput.Quality of service with Racian fadingNow we’ll define the QoS by changing the channel property as Racian fading. Graph 4.5 Packet delivery ratioGraph 4.5 is the graph of packet delivery ratio for Racian fading. Here we can see thepacket delivery ratio for 2048 and 1024 is much heigher than that of FFT value 512 and128. But when we talk about data rates the ratio is about to constant for the FFT 512 and128, but for othe FFT value the ratio is firdt decreasing and then it is constant. Graph 4.6 average jitterGraph 4.6 is the graph of average jitter. As we know Jitter is the variation in arrival timesof successive packet from a source to a destination. Here we can see when we arechanging the values of FFT there is little effect on jitter, but with increasing the data ratesjitter is decreasing continuously. So we can say jitter is inversely proportional to datarate, it means at increasing data rates jitter is decreasing. We can also that jitter forRacian fading is same as the jitter for Rayleigh fading. 143
  6. 6. International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN 0976– 6464(Print), ISSN 0976 – 6472(Online) Volume 3, Issue 1, January- June (2012), © IAEME Graph 4.7 Average delayGraph 4.7 is the graph of delay with Racian fading. Here we can see dalay for FFT value2048 and1024 is much heigher then delay with FFT value 512 and 128. So we can sayFFT and delay are directly proportional to each other. At all the data rates the delay isabout to same depending upon the FFT values. Graph 4.8 ThroughputGraph 4.8 is the graph of throughput. Here we can see throughput is increasing withincreasing Data rate, it means throughput is ditrectly proportional to data rates. But whenwe talk about FFT there is little effect of FFT at throughput. We can also throughput withRayleigh fading is same as throughput with Racian fading.IV. CONCLUSIONHere we’ll find the conclusion using finding the value of Trade off Index, which is usedto find that on which channel properties we’ll get the best quality of service. There arethree channel properties in which we are finding the QoS. These properties are done withRayleigh fading and with Racian fading. The value of TOI (trade off index) will be foundby the formula.It is measured as the formula- TOI= (a*throughput) + (b*packet delivery ratio)/(c*delay) + (d*jitter) 144
  7. 7. International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN 0976– 6464(Print), ISSN 0976 – 6472(Online) Volume 3, Issue 1, January- June (2012), © IAEMEWhere a, b, c, d are the weights which depends upon the person, who is trying to evaluatethe efficiency. In this paper work throughput, delay, jitter and average packet deliveryratio are there to calculate trade off index.For calculating, trade off index firstly we’ll show the values of above tables, then we’llimplement another graph by comparing these values. Here we have shown someconstants as a, b, c and d, the values for all these constants will be put as some unit place,So every value has to be brought as unit place, whatever is in points will be multiplied bypositive power of 10, and if not in the points then multiplied by negative power of 10.Trade of index with Rayleigh fading Graph 5.1Here for conclusion we are having the graph of TOI. As we know by using TOI we haveto find on which value of FFT we’ll get the maximum TOI. From the above graph we cansee the FFT value for 128 we’ll get the maximum trade off index.Trade off index with Racian fading Graph 5.2Now we’ll find the maximum TOI for Racian fading. Here we can see that for the FFTvalue of 512 we’ll get the maximum TOI.So we can conclude that the best FFT value for Rayleigh fading is 128 and forRacian fading the optimum FFT value is 512. 145
  8. 8. International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN 0976– 6464(Print), ISSN 0976 – 6472(Online) Volume 3, Issue 1, January- June (2012), © IAEMEV. REFERENCES[1] Mark Norris and Adrian Golds. Why WiMAX?URL:http://www.intercai.co.uk/library/pdf/Why-WiMAX. pdf. D. E. Comer.Internetworking with TCP/IP - Principles, Protocols and Architecture. 5th ed. PearsonEducation, 2006. [2] Benjamin Baumgrtner. Prinzip MIMO. URL: http://en.wikipedia.org/wiki/File:Prinzip MIMO.svg.[3] Sylvain Ranvier. Overview of MIMO systems. URL: http : / /www. comlab . hut . fi /opetus / 333 / 2004slides / topic47.pdf. [4] J. F. Kurose and K. W. Ross. Computer Networking A Top-Down Approach. 4th ed.Pearson Education, 2008.[5] Byeong Gi Lee and Sunghyun Choi. Broadband Wireless Access and Local Networks- WiMAX and WiFi. Artech House, 2008.[6] Loutfi Nuaymi. WiMAX: Technology for Broadband Wireless Access. 1st ed. JohnWiley and Sons, 2007.[7] What is IEEE 802.16e? URL: http://www.wimax.com/ wimax-technologies-standards/what-is-ieee-80216e.[8] Computer World. URL: http : / /www. computerworld .com/s/article/9215414/IEEEapproves next WiMax standard?taxonomyId=15.et al. A. Bacciocola. “IEEE 802.16:History, Status and Future Trends”. In: Computer Communications (2009).[9] Loutfi Nuaymi Aymen Belghith. Design and Implementatio of a QoS-includedWiMAX Module for NS-2 Simulator. Tech. rep. TELECOM Bretagne, 2008.[10] Robert Bestak Pavel Mach. “Analysis and Performanc Evaluation of IEEE 802.16Enhanced with Decentrally Controlled Relays”. In: IWSSIP 2009 146

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