Performance Improvement of Wi-MAX System using QAM Modulation and Moving Average Filter

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International Journal of Emerging Technology and Advanced Engineering

Website: www.ijetae.com (ISSN 2250-2459,ISO 9001:2008 Certified Journal, Volume 4, Issue 9, September 2014)

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Performance Improvement of Wi-MAX System using QAM

Modulation and Moving Average Filter

Smriti Shrivastava

1

, Prof. Md. Abdullah

2

Department of Electronics and Communication Engineering, Sagar Institute of Science and Technology, Bhopal, M.P., INDIA

Abstract - WiMAX is introduced by the Institute of Electrical and Electronic Engineers (IEEE). Wireless provides a worldwide interoperability for microwave access. Now-a-days telecommunication industries are highly concerned with the wireless transmission of data, which can employ many transmission types, from point to multipoint links. It contains full mobile internet access. several applications have already been applied so far using Wi-MAX, as alternative to 3G mobile systems in developing countries, Wireless Digital Subscriber Line (WDSL), Wireless Local Loop (WLL). IEEE 802.16e-2005 has been developed for mobile wireless communication which is based on OFDM technology and this enables going towards the 4G mobile in the future. In this paper , we built a simulation model based on moving average

filter implementation and demonstrated in different

simulation scenarios with different modulation techniques such as BPSK, QPSK and QAM (Both 16 and 64) to find out the best performance of physical layer for WiMAX Mobile. All the essential conditions were implemented in the

simulation according to the 802.16e OFDMA-PHY

specification. The noise channel AWGN, Rayleigh fading, data

randomization methods, FFT, IFFT, and Adaptive

modulation is used for the whole simulation method. The performance has been concluded based on BER, SNR and Pe outcome through MATLAB Simulation.

Keywords-- Wi-Max, BPSK, QPSK, QAM, and Moving Average Filter.

I. INTRODUCTION

WiMAX is called the next generation broadband wireless technology, which provides high speed, security, sophisticate and last mile broadband services along with a cellular back haul and Wi-Fi hotspots. The development of WiMAX began a only some years ago when scientists and engineers felt the need of having a wireless Internet access and other broadband services which works well everywhere especially the rural areas or in those areas where it is hard to establish wired infrastructure and economically not feasible.

IEEE 802.16, also known as IEEE Wireless-MAN, provides both licensed and unlicensed band of 2-66 GHz which is standard of fixed wireless broadband and included mobile broadband uses.

WiMAX forum, a private organization was formed in June 2001 to coordinate the components and develop the equipment those will be compatible and inter operable. After several years, in 2007, Mobile WiMAX equipment developed with the standard IEEE 802.16e got the certification and they announced to release the product in 2008, as long as mobility and nomadic access. The IEEE 802.16e air interface based on Orthogonal Frequency Division Multiple Access (OFDMA) which main aim is to give better performance in non-line-of-sight environments. IEEE 802.16e Standard introduced scalable channel bandwidth up to 20 MHz, Multiple Input Multiple Output (MIMO) and AMC enabled 802.16e technology to support peak Downlink (DL) data rates up to 63 Mbps in a 20 MHz channel through Scalable OFDMA (S-OFDMA) system [2]. IEEE 802.16e has strong security architecture as it uses Extensible Authentication Protocol (EAP) for mutual validation, series of strong encryption algorithms, CMAC or HMAC based on message protection and reduced key lifetime [4].

Attenuation

Each signal has a specific strength. To reach to a distant receiver, a signal must be strong enough to be detected by the receiver. When a signal travels in the air, gradually it becomes weaker over time and this phenomenon is called Attenuation. WiMAX is considering this issue carefully as it works on both LOS and NLOS environment.

Multi Path Fading

When an object comes on the way between a wireless transmitter and a receiver, it blocks the signal and creates several signal paths known as multi path. Even though the signal makes till the receiver but with variant time and it is hard to detect the actual signal. Multi path degrade the quality of the signal. Several multipath barriers which as follow:

II. WI-MAX ARCHITECTURE

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International Journal of Emerging Technology and Advanced Engineering

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The WiMAX Network Working Group (NWG) has developed a network reference model according to the IEEE 802.16e-2005 air interface to make certain objectives of WiMAX are achieved.

To support fixed, nomadic and mobile the network reference model can be rationally divided into three parts [6]

Mobile Station (MS)

It is for the end user to access the mobile network. It is a portable station able to move wide areas and perform data and voice communication. It has the entire necessary user equipments for example an antenna, an amplifier, the transmitter, receiver and software required to perform the wireless communication. GSM, TDMA, FDMA, CDMA and W-CDMA strategies etc are the examples of Mobile station.

Access Service Network (ASN)

It is owned by NAP, formed with one or several base stations and ASN gateways (ASN-GW) which creates radio access network. It provides entire access services with full mobility and efficient scalability. Its ASN-GW controls the access in the network and coordinates between data and networking elements.

[image:2.612.334.563.340.521.2]

Connectivity Service Network (CSN): Provides IP connectivity to the Internet or other public or corporate networks. It also applies for every user policy management, location management, address management, between ASN QoS, roaming and security.

Fig 2.1: WiMAX Network Architecture based on IP [6]

Mechanism

WiMAX is capable of working in different frequency ranges but according to the IEEE 802.16, the frequency band is 10 GHz - 66 GHz.

A typical architecture of WiMAX includes a base station built on top of a high rise building and communicates on point to multi-point basis with subscriber stations which can be a business organization or a home. The base station is linked through Customer Premise Equipment (CPE) with the customer. This connection can be a Line-of-Sight or Non-Line-of-Sight. Uses higher frequency between 10 GHz to 66 GHz

 Huge coverage areas

 Higher throughput

 Less interference

 Threat only comes from atmosphere and the characteristic of the frequency

 LOS requires most of it’s first Fresnel zone should be free of obstacles

Fig 2.8: Fixed and Mobile WiMAX in different applications

III. PROPOSED METHODOLOGY

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International Journal of Emerging Technology and Advanced Engineering

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Fig. 3.1. Shows Block Diagram of Proposed Methodology

OFDM Transmitter

Add Cyclic Prefix Encoder Interleaver Modulation

(BPSK/QPSK/ QAM)

IFFT

Data

Input

Noise Add AWGN Channel

OFDM Receiver

Remove Cyclic Prefix FFT

Demodulation (BPSK/QPSK/

QAM)

De-Interleaver

Decoder Moving

Average Filter

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International Journal of Emerging Technology and Advanced Engineering

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Fig. 3.2. Shows Flow Graph of Proposed Methodology

As the above flow graph shows the whole procedure of Proposed Methodology in this firstly, we initialize the environmental variables then data has been generated and encoded after that interleaving of data has been done then modulation schemes has been implemented and there after Orthogonal Frequency Division Multiplexing method adopted with AWGN Addition after vice versa above procedure the Moving Average Filtration technique is used to minimize the error possibility of WiMAX.

IV. SIMULATION RESULTS

IEEE 802.16 Wi-Max system has been simulated and found out results of its performance with different modulation techniques. Here to increase the performance of existing Wi-Max system we have also analyzed system with moving average filter (MAF) with each modulation technique. Now the effect of these techniques enhances when the number of iterations increased, i.e. when the repetition of frame is done more time the error rate of system decreases significantly. In below figures all the techniques and their performance is shown. The results is calculated in terms of BER vs SNR.

Fig.1. Wi-Max system performance with 5 iterations

Fig. sss.1 shows the performance of Wi-Max system under the condition of 5 iterations and three modulation techniques BPSK, QPSK and QAM with and without filter, and it is observed that BPSK and QPSK without filter and BPSK and QAM with filter gives better error performance.

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Wi-Max Model with 5 Iterations

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International Journal of Emerging Technology and Advanced Engineering

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Fig. 2. Wi-Max system performance with 10 iterations

Fig. 2 shows the performance of Wi-Max system under the condition of 10 iterations and three modulation techniques BPSK, QPSK and QAM with and without filter, and it is observed that BPSK and QPSK without filter and BPSK and QAM with filter gives better error performance.

0 5 10 15 20 25 30

10-6 10-5 10-4 10-3 10-2 10-1 SNR dB Bi t Er ro r R a te

BPSK QPSK QAM BPSK-MAF QPSK-MAF QAM-MAF

0 5 10 15 20 25 30

10-6 10-5 10-4 10-3 10-2 10-1 100 SNR dB Bi t Er ro r R a te

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10-7 10-6 10-5 10-4 10-3 10-2 10-1 100 SNR dB Bi t Er ro r R a te

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10-7 10-6 10-5 10-4 10-3 10-2 10-1 100 SNR dB Bi t Er ro r R a te

[image:5.612.325.582.124.346.2] [image:5.612.54.301.129.345.2] [image:5.612.51.301.428.635.2] [image:5.612.327.575.429.638.2]

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International Journal of Emerging Technology and Advanced Engineering

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Fig. 6 shows the performance of Wi-Max system under the condition of 50 iterations and three modulation techniques BPSK, QPSK and QAM with and without filter, and it is observed that BPSK and QPSK without filter and BPSK and QAM with filter gives better error performance. After comparison of all the results it can be say that with higher iterations we can achieve better results in terms of error rate, with less complex modulation techniques.

V. CONCLUSION AND FUTURE SCOPE

Various techniques has been used to enhance the performance of Wi-Max system previously. In the same context we have simulate the IEEE 802.16 Wi-Max standard, the simulation results shows that the performance of the Wi-Max system increased when it is operated with QPSK modulation scheme or QAM modulation scheme with moving average filter (MAF) and repetitions.

In future more advance filter will also help to get better performance and higher speed processors make system faster to repeat the transmission frame which is added advantage with the system.

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