Lavish Kansal ¹

Affiliations
1 Lovely Professional University, IN

Abstract

OFDM comes out as a key technology in contemporary wireless communication systems. OFDM offers a diverse kind of advantages like fading immunity, eminent data rate transmission, and efficient bandwidth capabilities. In order to have a reliable error-free communication, various channel coding schemes viz. Convolution Codes (CC), BCH and Reed-Solomon (RS) encoding and decoding schemes are being used at the transmitter and receiver side. These channel encoding schemes makes possible the error detection and correction possible at the receiver end. In present work, an OFDM system based on the diverse level of M-PSK digital modulation scheme is demonstrated integrating dissimilar channel encoding techniques over the Rician fading channel.  BER assessment as a function of SNR is being presented for the simulated test-bed. The simulation results present a substantial enhancement in BER performance of the simulated system using BCH over CC and RS.

Keywords

OFDM; CC; BCH; RS; M-PSK

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Rimple Manni ¹, Lavish Kansal ¹

Affiliations
1 School of Electronics and Electrical Engineering, Lovely Professional University, Phagwara - 144411, Punjab, IN

Abstract

Among security challenges raised by mobile Wireless Sensor Networks, clone attack is particularly dreadful since it makes an adversary able to subvert the behavior of a network just leveraging a few replicas of some previously compromised sensors. In this work, we propose a method named as Detecting Node Masquerade Attack using RLE Method which is used for detecting a clone in the network using RLE method. The main goal of our proposed protocol is to detect the replica of the nodes i.e. clones in the network on the basis of RLE method. RLE method is abbreviated as RSSI and List Exchange method i.e. R represents RSSI means received signal strength indicator. After that we also compare our proposed protocol with the known method i.e. Hip-Hop protocols which are also used to find a clone in mobile WSN and our simulation shows that our proposed protocol outperforms the existing approach in terms of detection rate and time taken to detect a clone. In future work, we can also use a clustering protocol to make this work more efficient.

Keywords

Reprogramming, Security, Sensor Networks

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Mahwash Manzoor ¹, Lavish Kansal ¹

Affiliations
1 School of Electronics and Electrical Engineering, Lovely Professional University, Phagwara - 144411, Punjab, IN

Abstract

Diverse modern wireless broadband communication systems are based on what is called Orthogonal Frequency Division Multiplexing (OFDM), which is a basic part of WiMAX. By making use of OFDM, we deal with frequency and time selectivity which are the major concerns when mobile or wireless communication is established between base and subscriber stations. WiMAX cuts the cost because it’s a wireless technology and hence there is little maintenance. Also, it provides higher data rates and has large coverage area compared to its counters parts. In this paper, we make a comparison of various channel coding techniques like convolutional codes, BCH codes, LDPC codes and RS codes over two fading channels namely Rayleigh channel and Rician channel and four modulation orders of PSK. The simulation results show that RS codes and BCH codes perform very well in all conditions whereas convolutional codes lag somewhat in their performance. In addition to this, Rician channel has a better response compared to Rayleigh channel in any modulation order or FEC codes being used in a WiMAX system.

Keywords

BCH, BER, FEC, LDPC, RS, WiMAX.

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Aanchal Jhingan ¹, Lavish Kansal ¹

Affiliations
1 School of Electronics and Electrical Engineering, Lovely Professional University, Phagwara – 144411, Punjab, IN

Abstract

OFDM systems due to its orthogonality factor provides significant spectrum efficiency, robustness to fading and simple cost effective implementation. One of the factors that effects the OFDM system performance is the Carrier Frequency Offset (CFO) that results in the Inter-Carrier Interference (ICI) which causes a degradation of the OFDM system performance. In this paper, a discussion on the performance of Discrete Wavelet Transform (DWT) OFDM and Fourier Transform (FFT) OFDM is done by considering the presence of CFO in both the systems. A comparative study of both the systems is done on the basis of Bit Error Rate (BER) performance these systems show. The system is considered on the basis of improvement in the BER. Simulations conclude that the system that uses wavelet implementation performs better than the conventional OFDM system. The DWT performance even with CFO factors shows considerable improvement in the bit error performance than the FFT based traditional system. Further, the whole simulation is done under the Rayleigh channel, the performance calculated for five practical values of CFO from 0 to 0.2 with step difference of 0.05. The BER performance is simulated using MATLAB software. Further, the whole simulation is done under the Rayleigh channel, the performance calculated for five practical values of CFO from 0 to 0.2 with step difference of 0.05. The DWT based OFDM outperforms the FFT based OFDM for all the values of CFO.

Keywords

BER, CFO, DWT, FFT, ICI, IDWT, IFFT, ISI, OFDM

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Aanchal Jhingan ¹, Lavish Kansal ¹

Affiliations
1 School of Electronics and Communication Engineering, Lovely Professional University, Phagwara - 144411, Punjab, IN

Abstract

Orthogonal Frequency Division Multiplexing (OFDM) is a multi-carrier based system that is selected to be used in the broadband wireless communication system. However, the main drawback considered for OFDM system is the Carrier Frequency Offset (CFO) which causes the Inter-Carrier Interference (ICI) that degrades the performance of the OFDM system. This paper discusses the performance of the system based on Bit Error Rate (BER) in the presence of CFO. For this, the estimation of CFO is carried over in both Discrete Wavelet Transform (DWT) OFDM and FFT OFDM for five different values of CFO (CFO = 0, 0.05, 0.1, 0.15, 0.2) in AWGN (Additive White Gaussian Noise) channel using the same procedure and their BER performance are simulated using MATLAB software. A comparative analysis on FFT-OFDM and DWT-OFDM systems is offered that shows that the performance given by DWT-based OFDM system is better in comparison to the FFT based OFDM system. BER results are simulated for BPSK, QPSK, 8-PSK, 16-PSK, 32-PSK modulations for both DWT and FFT based OFDM models. The analysis of MATLAB simulation clearly shows that the DWT-OFDM offers an improvement of 5-10 dB for the diverse order of modulations over AWGN channel.

Keywords

CFO, DWT, FFT, IDWT, IFFT, OFDM

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Aanchal Jhingan ¹, Lavish Kansal ²

Affiliations
1 Department of Electronics and Communication Engineering, Lovely Professional University, Punjab, India, IN
2 Department of Electronics and Communication Engineering, Lovely Professional University, Punjab, IN

Abstract

Orthogonal Frequency Division Multiplexing (OFDM) is a popular kind of multi-carrier based transmission technique that has found its applications in some wireless and wireline systems. But this system suffers from several facts that degrade its performance resulting in the interference of sub-carriers. Carrier Frequency Offset (CFO) is considered as one of the factor that causes interference in the system, leading to an Inter-Carrier Interference (ICI) between the carriers that results in a degradation in the performance factor of the system. In this research work, a comparative estimation is done on the Bit Error Rate (BER) performance of Discrete Wavelet Transform (DWT) OFDM and Fourier Transform (FFT) OFDM in the presence of CFO in both of the given systems. The research focuses mainly on the improvement of the BER in the system. The complete analysis is done by considering the channel to be Rician and the systems performance is estimated for some practical values of CFO. The complete simulation is done in the MATLAB. As the CFO increases the error in the system also increases, but still in that situation, DWT shows better improvement than the conventional system. The BER performance of OFDM systems shows improvement for all the diverse PSK modulation.

Keywords

BER, CFO, DWT, FFT, ICI, IDWT, IFFT, ISI, OFDM

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Mahwash Manzoor ¹, Lavish Kansal ¹

Affiliations
1 School of Electronics and Electrical Engineering, Lovely Professional University, IN

Abstract

The Wireless Interoperability Microwave Access (WiMAX) system in this paper makes use of various forward error correction codes to improve and hence optimize the performance of the system. Two diverse fading channels have been used to study the response of the WiMAX system based on Forward Error Correction (FEC) encoding and M-ary Phase Shift Keying (M-PSK) modulation. Since WiMAX is used for both Line Of Sight (LOS) and Non Line-Of-Sight (NLOS) communication so, Rayleigh and Rician channels have been used, out of which one has LOS component, and other has no LOS component. The performance of WiMAX system has been studied by analyzing the graphs between Bit Error Rate (BER) and Signal to Noise Ratio (SNR) for all the different cases. It is observed that out of all coding techniques reed Solomon (RS) encoding techniques performs better at lower order modulation schemes by providing the BER of 10-3 at lower values of SNR in comparison to all other FEC encoding techniques. But, at higher order modulation level turbo encoding scheme outperform all other FEC schemes. Also, out of channels rician channel has a better response because of one strong line of sight constituent in comparison to Rayleigh fading channel. Further, modified FEC encoding schemes can be incorporated to enhance the BER performance of the WiMAX system.

Keywords

BER, Fading, FEC, MPSK, WiMAX.

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Mahwash Manzoor ¹, Lavish Kansal ¹

Affiliations
1 School of Electronics and Electrical Engineering, Lovely Professional University, Phagwara - 144411, Punjab, IN

Abstract

WiMAX is the most popular wireless technology these days for it has high data rates and better performance than other wireless and wired broadband technologies. The performance of WiMAX is severely affected by the multipath fading environment. The efficiency of the WiMAX system can be improved using efficient forward error coding schemes. In this paper a comparison of various FEC schemes such as BCH, RS, LDPC and convolution encoding has been done on two different channels namely-Rayleigh and AWGN. The BER performance of the WiMAX system is further analyzed by utilizing diverse modulation levels over both Rayleigh and AWGN channel. The simulation results show that the best performance is achieved by RS codes and BCH codes followed by LDPC codes and then the convolutional codes. Also, as we vary the code rate of the convolution encoder the BER further degrades. The graphical representations show that the improvement can go as high as 4 dB in some cases in terms of SNR required achieving a particular BER value. The use of RS and BCH encoding schemes will result in better performance in existing WiMAX systems.

Keywords

AWGN, BCH, FEC, LDPC, WiMAX.

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Aanchal Jhingan ¹, Lavish Kansal ¹, Navdeep Singh Dhaliwal ¹

Affiliations
1 School of Electronics and Electrical Engineering, Lovely Professional University, Phagwara – 144411, Punjab, IN

Abstract

A multiplexing technique named Orthogonal Frequency Division Multiplexing (OFDM) has been widely used in a broadband wireless communication system. This technique can provide the larger data rates with the capability of showing enough strength to the impairments caused by the radio based channels. The OFDM based systems are supposed to be sensitive towards the errors that originate due to the frequency mismatch in the form of the Carrier Frequency Offset (CFO) effect. That further leads to an effect named Inter-Carrier Interference (ICI). ICI mainly occurs due to the inconsistency in the frequencies of the local oscillators that are present together at the transmitter and the receiver side. For compensating the effect of the CFO, the researchers have proposed different types of methods and algorithms used for estimation and its correction by now. In this research, the reason for the generation of the CFO and its effects are shown on the performance of the system is studied. The main algorithms and techniques for the CFO estimation and correction are reviewed and discussed in the literature briefly and also discussed a proposed and an efficient method for the estimation and compensation of the CFO is proposed.

Keywords

BER, CFO, ICI, ISI, OFDM.

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Akanksha Sharma ¹, Lavish Kansal ¹

Affiliations
1 School of Electronics and Electrical Engineering, Lovely Professional University, Phagwara – 144411, Punjab, IN

Abstract

Orthogonal Frequency Division Multiplexing (OFDM) is mostly considered because of its highly efficient bandwidth capability, its high data rate and ability to prevent multipath fading. It is much suitable technique for parallel transmission and use Wireless interoperability for Microwave Access (WiMAX) on its physical layer. Higher the speed of communication better will be the veracity in it. This broadband is trying its best to get available to every place where they are lagging behind and should be accessible to all as soon as possible. On the other hand, Multiple Input Multiple Output (MIMO) techniques are important part of IEEE 802.16e 2005 specifications in adaptable WiMAX systems. From WiMAX technology, we can conquer the current problems of mobile communication systems like precise coverage of area, flat data rate and dearth of security. In this paper, the focus is on WiMAX model along with MIMO techniques. Moreover, ideas regarding MIMO-WiMAX are also highlighted.

Keywords

MIMO, OFDM, SD, SM, WiMAX

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Ashish Jha ¹, Lavish Kansal ¹

Affiliations
1 School of Electronics and Electrical Engineering, Lovely Professional University, Phagwara – 144411, Punjab, IN

Abstract

As Least Square (LS) and Minimum Mean Square Error (MMSE) do not give the satisfactory result to justify the features of the wireless channel, Compressed Sensing (CS) based on Discrete Sine Transform (DST) for channel impulse response has been studied which gained much more importance in digital signal processing. We have used Compressed Sensing to estimate the channel coefficients of the fading channel; then we have performed the CS recovery algorithm to estimate the channel and to nullify the fading effect, the thus much better result are obtained in the simulation which satisfies the better performance of the system as compared to the traditional method. Simulation results show a considerable improvement in Bit Error Rate (BER) performance on employing the Compressed Sensing approach in comparison to LS and MMSE. The improvement of the order of 2-9 dB of SNR is for a particular value of BER.

Keywords

Channel Estimation, Compressed Sensing, DST, LS, MMSE, OFDM.

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Shiwani Sandal ¹, Lavish Kansal ¹

Affiliations
1 School of Electronics and Electrical Engineering, Lovely Professional University, Phagwara – 144411, Punjab, IN

Abstract

Orthogonal Frequency Division Multiplexing (OFDM) has great demand in wideband digital communication. It encodes the data on multiple carrier frequencies. Its application areas are digital audio broadcasting and high definition television, wireless network, 4G mobile communications. Due to its great advantages like it provides high spectral efficiency, remove inter symbol interference, reduced nonlinear distortion it is widely used for communication purpose. Major problem of this scheme is high Peak to Average Power Ratio (PAPR). To overcome this problem i.e. PAPR, here in this paper we figure out different reduction techniques, there pros and cons and also find Selective Mapping (SLM) is better technique due to its several advantages with reduced PAPR and better Bit Error Rate (BER) which is discussed further in this paper.

Keywords

Hybrid Techniques, OFDM, PAPR, Precoding Techniques, Reduction Techniques

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Mahwash Manzoor ¹, Lavish Kansal ¹

Affiliations
1 School of Electronics and Electrical Engineering, Lovely Professional University, Punjab – 144411, IN

Abstract

WiMAX is the modern era wireless technology which gained popularity because of its efficiency, high coverage, scalability and high data rates in any terrain. WiMAX is a Wireless Metropolitan Area Network (WMAN) being used globally for broadband access. There is always a demand for improvement in systems, which in the case of WiMAX can be achieved by using a better coding scheme with a proper modulation technique. In this paper, a comparison has been made on performances of different forward error correction codes on two channels- AWGN and Rayleigh channel. AWGN channel simply adds white Gaussian noise to the signal transmitted through it whereas Rayleigh channel is a fading multipath channel whose characteristics vary continuously with time. The results show that Turbo codes perform the best amongst all the coding techniques, and AWGN channel response is much better than the response of Rayleigh channel. This is because there is no line of sight component in Rayleigh channel and having obstructions in the path of the signal leads to signal fading. These results are shown in this paper as graphical analysis between BER and SNR.

Keywords

Additive White Gaussian Noise (AWGN), Bit Error Rate (BER), Signal to Noise Ratio (SNR), Wireless Metropolitan Area Network (WMAN), Worldwide Interoperability for Microwave Access (WiMAX).

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