Simulation of Modulation Techniques for Wireless Communications Using Matlab - Lab Report Example

Simulаtiоn/Аnаlysis оf Моdulаtiоn Тесhniquеs fоr Wirеlеss Соmmuniсаtiоns Using Маtlаb Name Class Instructor Institution City State Date Abstract Due to growth in communication sector there is a new introduction of wireless communication but this has some setbacks that have to be overcome for good and effective wireless communication. Unlike fixed communications lines wireless have challenges such as fading and noise. For competitive advantage customers always demand quality services and products. Orthogonal frequency division multiplexing (OFDM) is technique in which is suitable for converting wide signals to narrow signals to be transmitted by orthogonal carrier. These papers the performance of methods chosen are evaluated by Bit Error Rate and Signal to Noise Ratio under Rician Fading channel as noise channel built in QPSK AND QAM technique. OFDM are implemented using subcarriers and performance is based and concluded on BER and SNR. From the findings it’s concluded that QPSK is better compared to 16-QAM has it has higher SNR values. Its known as that SNR increase BER decreases but the performance of the technique increases hence Table of Contents Abstract 1 Table of Contents 2 Introduction 3 PROPOSED SYSTEM MODEL 4 Simulation methodology 6 Performance analysis and results 8 Findings of performance analysis 12 Conclusion 14 References 15 Introduction Radio waves move in light speed and are measured in Herts, Carrier waves have different properties which include bending and penetrate on walls, for this wave to carry on it has to be modulated by three methods which are amplitude shift keying that increase power of wave e.g. AM waves, frequency shift keying which step up signals with digital signals e.g. in FM which reduces noise and phase shifting that changes carrier phase in step with digital message. Both QPSK and QAM are used in latest techniques such as WIFI, WIMAX and 3G which are latest wireless improvements in the communication industry. Recently they have been increased attention on non-wired communication from wired public networks. This is because WBMCS as traditional public networks cannot be extended to wireless mobile networks as they are more complicated(Vishwas 2012). GSMK is a mostly used technique in GSM which can transmit data at 1 bit per symbol making it not suitable to coming communication system. It’s important to study new modulations that can generate higher rate in AWGN channel. Digital modulations are have more advantages than analogue schemes hence when choosing a modulation technique one has to match the performance required to be achieved, performance characteristics that has to be met by the technique and requirements of that technique (Harjot 2011). Performance of M-ary modulations e.g. M-PSK and M-QAM when transmitting signal over AWGN is better compared to low level moderation such as 4-PAM and 16-QAM. In today’s telecommunication each company want to pass most information on limited bandwidth. OFDM has conquered this by giving more channels on limited bandwidth channel, unlike FDM which provide a guard between channels OFDM adjacent channels overlap but interface avoided by orthogonal between sub-carriers. The transmission of band signals are done by orthogonal carrier hence OFDM can be either be a modulation or multiplexing technique hence a good reason to ensure reduced fading and band interference while communicating in devises. PROPOSED SYSTEM MODEL In OFDM each subcarrier has modulation vector symbol( Mohamed 2010) v(t) = v˜(t)ej2π fct. which is summarized as Ac – peak amplitude of carrier ωn – n element of vector In which it can be summarized as This is a OFDM model prepared and used in broadcasting systems which was made in 1990s .with the following algorithm. That was used in code to analyze data (Yi 2011) Simulation methodology In this study in which aim atanalyzing the differences between QPSK and 16- QAM which are some of modulation schemes the project will be set in the bit rate to be 384 Kbps from the source signal and resulting to a simulation chart by use of Simulink and M files according to Sweeney (2001) Air-Interface Techniques for Achieving High Data Rates for UMTS It involves shift register that is used to produce codes in WCDMA, it contains number of cells from I to indefinite r in which they are controlled by clock pulse that reads move output content while reading inputs. In this feedback the input m will be out put function of cell m-1 (Rosmansyah, 2001) In LFSRs the combinations of functions of cells m-1 and cells 1 would result to linear. Below shows a binary shift that can generate a polynomial sequence of h(x) = x5 + x2 + 1in which it can be concluded that (Ergen 2009) h(x)=hnxn +hn-1xn-1+…..h1x1+1 (hi€{0,1}) Binary shift register of h(x) = x5 + x2 + 1 Performance analysis and results It’s analysis of BER and SNR using 2 ray tracing and AWGN channel with one user with a data range of 200000. The following table shows performance WCDMA of one user in moderation of QPSK technique in AWGH in which BERs were obtained by changing values from 0-20 in Eb/ No in which it’s done 10000 times to produce data of 200000 (Sahasha 2013) Simulation parameter table bits per symbol 52 Symbols 10000 FFT length 64 Subcarrier number 52 Modulation technique QPSK and 16 QAM Noise channel Rayleigh rician Signal frequency 8 MHz Using BER at SNR =12 QPSK-BER>10-4 and 16 QAM-BER>10-2. In simulation also they checked performance of W-CDMA but using I user channel and data is done at 60kmph and 90kmph for as shown below for a data of 200000 Findings of performance analysis In above simulations the following results were obtained.i which simulations using the m files show that each of the techniques had a good performance. When the channels was increased value of hertz there was a change in performance of both techniques. It shows that 1 Below table shows summery of BER and SNR of both techniques that is QPSK and 16-QAM technique on Rician channel in which BER decrease which is a clear indicator of better performance. As for better communication the noise should be low. In which it shown that QPSK has better performance as evidenced in the table.Each symbol represents two bits in QPSK and four bits per symbol in 16-QAM and with no coding is used to improve the PAPR.(Byungwook,2007) In the above simulation it shows how these techniques are compared in which its shown that both have poor performance when Doppler shift or mobile terminal is increased. In comparison of both its shown that the system that is used in testing 16- QAM performs poorlyin both when tested in LOS channel and multipath fading channel as shown in above tables. Using m files it also notes when amplitude is varied it causes 16-QAM signal constellation this is due to the reason adjacent carries interference this can only be overcome by sound approach or use of smart antennae or RAKE receivers to generate multi path for delayed signals (Marks 2004) Compared to other techniques QPSK has reduced bandwidth by half compared to similar techniques with similar bit rated, with bandwidth reduced QPSK has higher transmission rate and has constant power as carrier power is constantit’s known that has aamplitude modulation as the distance in the plane reduces noisecompared to QAM. QAM has efficiency in transmission for radio due to amplitude and variations of phase. But it has limitations in which are first it susceptible to noise unlike the other technique. The second limitation is that when amplifying in QAM linearity is maintained and isineffective this is because these amplifiers use a lot of power.(Emdadul 2011) Conclusion In this paper performance of OFDM has been observed and analysis done basing on SNR and BER the work has further been explained by use of graphs and mat lab based programme to produce report that is analyzed to help in evaluation. In today communication sector Limitedbandwidth is major challenge in telecommunication. As some bits and informational are lost due to signal fading, in comparison of both QPSK and 16-QAM through fading signal shows that QPSK has a better performance compared to QAM this is because when the mobility in above exercise is changed from 60-120 kmph16-QAM has signal degradation. For one to pass large information error correction code must be used to reduce constellation. In conclusion 16 QAM technique is used in3G or 3.5G high speed transmission in static environment that can rate 20Mbps however it has a setback in which it has degradation in noise compared to QPSK. This is due to interference from carrier’s phase hence coding such as convolution and turbo to eliminate constellation References Md. Emdadulhaque , Md. Golamrashed, M. Hasnatkabir;„ A Comprehensive Study And Performance Comparison Of M-Ary Modulation Schemes For An Efficient Wireless Mobile Communication System‟, International Journal Of Computer Science, Engineering And Applications (Ijcsea) Vol.1, No.3,Pp. 39-45, 2011. Vishwasgirigoswami, Sandhya Sharma, „Performance Analysis Of Different M-Ary Modulation Techniques Over Wireless Fading Channel‟, Iosr Journal Of Electronics And Communication Engineering (Iosr-Jece),Vol. 4, Issue 1, Pp.32-38, 2012. Harjotkaur, Bindiya Jain, Amitverma,‟ Comparative Performance Analysis Of M-Ary Psk Modulation Schemes Using Simulink‟, International Journal Of Electronics & Communication Technology (Iject), Vol. 2, Issue 3, Pp. 204-209, 2011. Sahashanamdeo,Reena Rani “Designing And Performance Evaluation Of 64 Qam Ofdm System”. Iosr Journal Of Electronics And Communication Engineering (Iosr-Jece) E- Issn: 2278-2834,P-Issn: 2278-8735.Volume 5, Issue 6 (Mar. – Apr. 2013), Pp 97-105. Y. Rosmansyah, P. Sweeney, R. Tafazolli, “Air-Interface Techniques For Achieving High Data Rates For Umts”, Ieee 3g Mobile Communication Technologies, Conference Publication No. 477, Pp. 368-372, 26-28 March 2001. M. Ergen, Introduction To Mobile Broadband. Individual Book Chapter. Springer, New York, Usa,2009. S. Yi, Y. Li, T. Liangrui And W. Wenjin, “Adaptive Resourceallocation Algorithm Based On Ieee 802.16 Ofdm”, Seventhieee International Conference On Natural Computation, 2011. Mohamed A. Mohamed, Mohamed S. Abo-El-Seoud And Hebam. Abd-El-Atty, “Performance Simulation Of Ieee 802.16ewimax Physical Layer” Seventh Ieee International Conference On Natural Computation, 2010 . R.B. Marks, K. Stanwood, D. Chang, Et Al. (October, 2004),Ieee Standard For Local And Metropolitan Area Networks, Partair Interface For Fixed Broadband Wireless Access Systems. Y. Byungwook, H. L. Kyu And L. Chungyong, “Implementationof Ieee 802.16e Mimo- Ofdma Systems With K-Best Latticedecoding Algorithm”, International Conference On Consumer Electronics. Las Vegas, Nv, Usa, 2007 Read More