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Comparative Study of Bit Error Rate of Different M-ary Modulation Techniques in AWGN Channel
Bourdillon O. Omijeh,
Ifiokabasi Eyo
Issue:
Volume 5, Issue 5, October 2016
Pages:
82-90
Received:
22 August 2016
Accepted:
31 August 2016
Published:
24 September 2016
Abstract: This paper focuses on various digital modulation schemes and their effect on bit error rate (BER); and to ascertain which has the lowest bit error rate. Further analysis includes: to compare bit error rates of various digital modulation schemes using the M-ary modulation technique, analyse the effect of varying signal energy per bit to Noise ratio (Eb/No) on the error rate of various digital modulation schemes, analyse graphically the relationship between Eb/No and BER, analyse graphically the relationship between BER and M-ary number. A model-based design methodology was employed in the research using MATLAB/SIMULINK. The comparison between different M-ary (M-PAM, M-PSK, and M-QAM) (M = 2, 4, 8, 16, 32, and 64) modulation schemes in normal AWGN channel was done. By analysing the graphical illustration of Eb/No vs BER of these M-PSK schemes it was strongly observed that increase in the value of M causes a correspondent increase in the error rate. Therefore, as the error rate increases with increasing M; lower level should be used for long distance communication and vice versa. High level modulation techniques are always preferred for high data rate.
Abstract: This paper focuses on various digital modulation schemes and their effect on bit error rate (BER); and to ascertain which has the lowest bit error rate. Further analysis includes: to compare bit error rates of various digital modulation schemes using the M-ary modulation technique, analyse the effect of varying signal energy per bit to Noise ratio ...
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Improving the BER Performance of M-FSK in a Noisy Multipath Rayleigh, and Rician Fading Channels Using Reed-Solomon Forward Error Correction Method
Bourdillon O. Omijeh,
Ekene Obodoekwe
Issue:
Volume 5, Issue 5, October 2016
Pages:
91-96
Received:
22 August 2016
Accepted:
31 August 2016
Published:
24 September 2016
Abstract: This paper focuses on the application of Reed-Solomon Error Correction Code evaluation technique on the Bit-Error-Rate performance of M-ary Frequency Shift Keying (M-FSK) in noisy multipath Rayleigh and Rician fading channel. The detection and correction of the received information errors from the multipath fading channel was done using the Forward Error Correction (FEC) technique. The message is encoded and decoded using the error-correcting Reed-Solomon Codes were employed to encode and decode the message. The entire model based design, modelling and simulation was done using MATLAB/SIMULINK. It was observed that the BER performance of M-FSK with RS codes improved greatly compared to M-FSK system without error correction. Decrease of BER performance was observed as the length of codeword symbols (n) increase at constant code rate and error correcting capability. The redundancy increases as code rate decreases leading to an improved Bit-Error-Rate performance. The improvement of the BER of M-FSK by using Reed-Solomon error correction code was achieved.
Abstract: This paper focuses on the application of Reed-Solomon Error Correction Code evaluation technique on the Bit-Error-Rate performance of M-ary Frequency Shift Keying (M-FSK) in noisy multipath Rayleigh and Rician fading channel. The detection and correction of the received information errors from the multipath fading channel was done using the Forward...
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The Study and Simulation of Adaptive Algorithms in Echo Cancellation of an Acoustic Signal
Mahnaz Namdaran,
Masoud Masomei,
Hamid Chegini
Issue:
Volume 5, Issue 5, October 2016
Pages:
97-106
Received:
5 September 2016
Accepted:
19 September 2016
Published:
11 October 2016
Abstract: Echo signal is the delayed form of an electrical or acoustic signal and it occurs when it returns to its source, in other words when acoustic signal finds its way from sending route through receiving one. One of the important parameters in discussing echo is delay time. In practical applications, if round trip time exceeds 30 milliseconds and echo power also exceeds 30 decibels, echo cancellation should be done. Today given the developments in utilizing communication system and transmitting acoustic information, echo cancellation becomes very important. There are different algorithms for cancelling echo of acoustic signals and each of them has both advantages and disadvantages. Adaptive filters are appropriate for echo cancellation. In such filters, minimization of the computational complexity and quick convergence of adapting is done within frequency domain owing to long impact response. In this study, different adaptive algorithms such as LMS, NLMS, VSLMS, VSNLMS and RLS have been suggested which can be used for echo cancellation and finally, a combination of them as an optimal algorithm was simulated for echo cancellation. In this paper, the stages of determining filter coefficients and the level of computational work in terms of convergence behavior, simulation results and other methods’ results were compared and it was found that using NLMS and MAX-E algorithms would offer best results in different situations. Innovative aspects of this paper include using adaptive algorithms in their real time and we can minimize the computational work of these algorithms and maximize the convergence speed by selecting accurate filter coefficients and the window used in computations. Also, we can use it in current applications and even in sound conversations on some communication networks like internet. Other aspects include using adaptive algorithms in implementing echo cancellation that have better function and convergence compared to blind methods of echo cancellation and they contribute to quality improvement of sent signals in conversations.
Abstract: Echo signal is the delayed form of an electrical or acoustic signal and it occurs when it returns to its source, in other words when acoustic signal finds its way from sending route through receiving one. One of the important parameters in discussing echo is delay time. In practical applications, if round trip time exceeds 30 milliseconds and echo ...
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An Improved Data Hiding in Encrypted Images
Aida Laee,
Masoud Masomei,
Hamid Chegini
Issue:
Volume 5, Issue 5, October 2016
Pages:
107-114
Received:
8 September 2016
Accepted:
21 September 2016
Published:
11 October 2016
Abstract: Nowadays in digital world, safeguarding information is an important phase in transmitting messages and doing trades. The increasing growth of computer networks has caused a lot of changes in life style, occupational activities and organizations. Thus, data security has been one of the essential issues in this area. By connecting a local network to global network, outsiders are likely to have access to the organizations’ data. One of the most important challenges about propagating information on internet is to assure inaccessibility of unauthorized people to sensitive information. Various solutions including restricting the use of internet, encoding the data and establishing security have been suggested. To fulfill the security requirements for a safe transaction, operations such as encoding, hiding, etc. are used. Today information is of great importance either in military area or in commercial one. Hence one of the basic needs is to maintain information for transmitting or storing them. Having access to coded information is not possible for unauthorized people and only those having password can decode and use them. Encoding the information is based on the knowledge related to that. On the one hand, hiding is also one of the effective techniques for keeping information since host information is clear and a hidden message may not be discovered. In this study, a new technique is presented for hiding information in encoded images which minimized the error of the previous techniques. In addition, previous techniques have never pointed out to noisy environments and one of the advantages of the introduced technique was to eliminate noise.
Abstract: Nowadays in digital world, safeguarding information is an important phase in transmitting messages and doing trades. The increasing growth of computer networks has caused a lot of changes in life style, occupational activities and organizations. Thus, data security has been one of the essential issues in this area. By connecting a local network to ...
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An Improved Routing Method for Electric Power Communication Networks
Issue:
Volume 5, Issue 5, October 2016
Pages:
115-120
Received:
18 October 2016
Published:
19 October 2016
Abstract: An improved routing method to reduce the risk of electric power communication networks (EPCN), called low risk routing method (LRRM), is proposed based on the fact that different types of traffic with different service importance levels in EPCN. In order to calculate the vulnerability of EPCN under artificial attacks, deliberate attack and betweenness first attack models are created. Based on the attack models, a routing model considering service importance distribution, edge betweenness distribution and path length is presented. Taking into account both network risk and service delay requirements, optimized routing is calculated using Dijkstra algorithm and chaotic clonal genetic algorithm (CCGA). Under different artificial attacks, the vulnerability of an EPCN applying LRRM and Shortest Path First method (SPFM) are compared by numerical simulation. The results show that LRRM can effectively reduce the network risk.
Abstract: An improved routing method to reduce the risk of electric power communication networks (EPCN), called low risk routing method (LRRM), is proposed based on the fact that different types of traffic with different service importance levels in EPCN. In order to calculate the vulnerability of EPCN under artificial attacks, deliberate attack and betweenn...
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