BER Vs SNR

The Multi-Carrier Code Division Multiple Access (MC-CDMA) is becoming a very significant downlink multiple access technique for high-rate data transmission in the fourth generation wireless communication systems. By means of efficient resource allocation higher data rate i.e. throughput can be achieved. This paper evaluates the performance of group (subchannel) allocation criteria employed in downlink transmission, which results in throughput maximization. Proposed algorithm gives the modified technique of sub channel allocation in the downlink transmission of MC-CDMA systems. Simulation are carried out for all the three combining schemes, results shows that for the given power and BER proposed algorithm comparatively gives far better results .

Mosaicing is blending together of several arbitrarily shaped images to form one large balanced image such that boundaries between the original images are not seen. Image mosaicing creates a large field of view using of scene and the result image can be used for texture mapping of a 3D environment too. Blended image has become a wide necessity in images captured from real time sensor devices, bio-medical equipment, satellite images from space, aerospace, security systems, brain mapping, genetics etc. Idea behind this work is to automate the Image Mosaicing System so that blending may be fast, easy and efficient even if large number of images are considered. This work also provides an analysis of blending over images containing different kinds of distortion and noise which further enhances the quality of the system and make the system more reliable and robust.

The turbo detection of turbo coded symbols over correlated Rayleigh flat fading channels generated according to Jakes' model is considered in this paper. We propose a method to estimate the channel signal-to-noise ratio (SNR) and the maximum Doppler frequency. These statistics are required by the linear minimum mean squared error (LMMSE) channel estimator. To improve the system convergence, we redefine the channel reliability factor by taking into account the channel estimation error statistics. Simulation results for rate 1/3 turbo code and two different normalized fading rates show that the use of the new reliability factor greatly improves the performance. The improvement is more substantial when channel statistics are unknown. K EYWORDS MAP-BCJR decoder, SNR, maximum Doppler frequency, turbo processing, channel reliability.

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Visible light communication VLC is deemed as futuristic technology applied for both illumination and data communication due to the low-cost energy consumption, long life expectancy, huge bandwidth, and high security compared to radio frequency RF. Uncovered area, minimum signal-to-noise ratio (SNR) and received power results from the non-uniform distribution of small base stations (i.e. Optical attocells) in the room. In this paper, the researchers propose a new LEDs distribution of five optical attocells configuration model in order to optimize the received power distribution and SNR at the center of the room for indoor VLC system. The optical attocells configuration in terms of received power to fill the uncovered area at the center of the room has been investigated. The simulation results showed that the proposed attocells configuration saved 24.9% of the transmitted power. Besides that, the whole room was covered uniformly.  As a result, the received power and SNR are improved.

With the increasing growth of multimedia applications over the networking in recent years, users have put forward much higher requirements for multimedia signals, particularly for image/video signal's quality of experience (QoE) than before. The objective approach of image quality assessment (IQA) plays an important role for the development of compression standards and various multimedia applications. However, the quality assessment of stereoscopic (3-D) images faces more new challenges, such as depth perception, virtual view synthesis, and asymmetric stereo compression. In this paper, we propose a new full-reference (FR) 3-D IQA method to measure the quality of the distorted images. The properties of the depth component, structure component, and gradient component are taken into account to establish the proposed metric. The experimental results show that the proposed metric is highly consistent with the subjective test scores compared with the existing related metrics. In addition, the main significance of the proposed metric is that it not only could effectively evaluate the quality of 3-D image but also has a satisfied effect for measuring the quality of 2-D image. Index Terms-Depth map, full-reference (FR), image quality assessment (IQA), quality of experience (QoE), three-dimensional (3-D) image. I. INTRODUCTION I N recent years, with the high-speed development of the communication systems, the multimedia applications over the networking have grown rapidly for many fields, such as live broadcast, video on demand, real-time conferencing, and so on [1] and [2]. People can have the access to use the network on any facilities, anyplace, and anytime. Consequently, the user have put forward much higher requirements for the quality of the multimedia signals than before; in particular, the video/image quality at the terminal is becoming the representative one in abundant emerging multimedia quality of experience (QoE). Currently, 3-D media services have been widely using Manuscript

Wireless communication using Multiple-Input Multiple-Output (MIMO) links has emerged as one of the most significant breakthroughs in modern communications because of the huge capacity and reliability gains promised even in worst fading environment. This paper presents an overview of some important behaviors of MIMO systems under Rayleigh channel environments. This work describes the basic ideas of MIMO transmission systems and focused and investigated the BER performance. All analysis was performed under ideal identical independent fading conditions by the use of MATLAB. At the initial stage of the work we related the SNR and the error performance of MIMO systems with the diversity schemes, in the later part of the paper, implementations of different equalizers are also verified for the improvement of the BER performance. Each chapter is rounded by a number of simulations to deepen the understanding of the performance with the use of multiple antennas and equalizers in wireless communication over Rayleigh wireless radio channels. MIMO fading channels are correlated to observe mutual coupling between antenna elements. Receiver diversity is analyzed especially with the Maximal Ratio Combining(MRC) technique and fair comparison is done with Equal Gain Combining(EGC) and Selection-Combing(SC). Further study is done with integration of Maximum Likelihood (ML), Maximum Mean Square Equalization(MMSE) and Zero Forcing(ZF). All the results obtained are simulated by using the MATLAB, under Rayleigh channel conditions.

Wireless communication using Multiple-Input Multiple-Output (MIMO) links has emerged as one of the most significant breakthroughs in modern communications because of the huge capacity and reliability gains promised even in worst fading environment. This paper presents an overview of some important behaviors of MIMO systems under Rayleigh channel environments. This work describes the basic ideas of MIMO transmission systems and focused and investigated the BER performance. All analysis was performed under ideal identical independent fading conditions by the use of MATLAB. At the initial stage of the work we related the SNR and the error performance of MIMO systems with the diversity schemes, in the later part of the paper, implementations of different equalizers are also verified for the improvement of the BER performance. Each chapter is rounded by a number of simulations to deepen the understanding of the performance with the use of multiple antennas and equalizers in wireless comm...

We consider blind channel estimation in a single-input single-output full-duplex communication system, where both the self-interference and the communication channels need to be accurately estimated. In this context, blind estimators are attractive as they improve bandwidth efficiency but they suffer from the phase ambiguity problem. In this paper, we first formally define and analyse this ambiguity and then develop a general framework for testing and designing modulation sets for blind estimation of channel parameters. We mathematically show that simply shifting the mean of the $M$-PSK modulation resolves the ambiguity problem. We also show how this can be extended to more general modulation sets. Finally, we propose an expectation maximization (EM) iterative estimator and a closed form minimum mean square error (MMSE) estimator for use with the shifted modulation set. Since the non-data aided Cram\'er-Rao lower bound (CRLB) or the Bayesian CRLB (BCRLB) are intractable, we deri...

Channel estimation algorithms have a key role in signal detection in MIMO-OFDM systems. In this system, the number of channel components which need to be estimated is much more than conventional SISO wireless systems. Consequently, the computational process of channel estimation is highly intensive. In addition, the high performance channel estimation algorithms mostly suffer from high computational complexity. In the other words, the system undergoes intensive computations if high performance efficiency is desired. However, there is an alternative solution to achieve both high performance efficiency and relatively low level of computational complexity. In this solution, high efficient channel estimation is firstly designed, and then it is simplified using alternative mathematical expressions. In this paper, Iterative channel estimation based on QR decomposition for MIMO-OFDM systems is proposed. From simulation results, the iterative QRD channel estimation algorithm can provide better mean-square-error and bit error rate performance than conventional methods.

This paper presents the modeling and simulation of the most innovative MIMO-VBLAST technique. Wireless communication has suffered from the fading problem ever since its first appearance in 1897, when Guglielmo Marconi transmitted a wireless signal to a ship in the English Channel. The following century witnessed the remarkable development of wireless communication, especially in the last decade. The capacity of traditional communication systems along with 1x1 antenna system would be very low because of multi path propagation within radio channels. The multi-path signals add up constructively or destructively at the receiver antenna to give a fluctuating signal, which can vary widely in amplitude and phase. When the amplitude of the signal experiences a low value it is termed fading and the capability of the wireless channel is severely limited. Several efforts into this direction have been carried out to make the radio channel more efficient and this has got remarkable progress. Efficient techniques, such as frequency reuse and OFDM, have been invented to increase the bandwidth efficiency; on the other hand, advances in coding techniques, such as Reed Solemn codes, Convolution codes and low density parity check (LDPC) codes make it possible to almost reach Shannon capacity the theoretical performance limit of the channel. However, the development of the techniques for a single channel has yet to catch up with the increasing demand for the capacity The most promising solution to combat this effect is to have antenna diversity scheme which can be implemented with many of ways such as BLAST structure, STBC coding technique, etc. With the implementation of antenna diversity i.e. MIMO, the capacity of the communication system as well as channel will increase in terms of improved error rate performance. Also with the implementation of BLAST structure the data rate of the communication can be enhanced at the same amount of bandwidth. Ultimately this paper concludes effect of MIMO-BLAST to provide array gain i.e high data rate for modern wireless scenario.

We consider blind channel estimation in a single-input single-output full-duplex communication system, where both the self-interference and the communication channels need to be accurately estimated. In this context, blind estimators are attractive as they improve bandwidth efficiency but they suffer from the phase ambiguity problem. In this paper, we first formally define and analyse this ambiguity and then develop a general framework for testing and designing modulation sets for blind estimation of channel parameters. We mathematically show that simply shifting the mean of the $M$-PSK modulation resolves the ambiguity problem. We also show how this can be extended to more general modulation sets. Finally, we propose an expectation maximization (EM) iterative estimator and a closed form minimum mean square error (MMSE) estimator for use with the shifted modulation set. Since the non-data aided Cram\'er-Rao lower bound (CRLB) or the Bayesian CRLB (BCRLB) are intractable, we deri...

In today's era where digital image processing is being widely used in several areas like data hiding, aerial imaging, video processing & medical field, etc. Image mosaicing is a field which is also emerging at a fast pace. It is the process of merging fragmented images that are obtained by scanning different parts of a single large image with certain part of overlapping region to produce a single and complete image. It is nothing but joining of two or more images and making a new and wide area image. In this paper, the process of feature detection will be discussed using Harris Corner Detection algorithm, which is our method of choice because of its advantages like consistency of detection, localization, stability, and low complexity. Application of Image Mosaicing is used here for medical images.

Image stitching is the process in which different photographic images are integrated together to form a segmented panorama or a high resolution image. Multiple images are overlapped and blended to form a wide angle panoramic image. The entire image stitching process is done by images taken from a camera and then applying the process on a computer software. The main steps include image acquisition, image registration image blending. The image registration process used in this method is a feature based method which uses HARRIS corner detection algorithm for feature detection. The image stitching algorithm is then processed to give a stitched panoramic image.

The turbo detection of turbo coded symbols over correlated Rayleigh flat fading channels generated according to Jakes' model is considered in this paper. We propose a method to estimate the channel signal-to-noise ratio (SNR) and the maximum Doppler frequency. These statistics are required by the linear minimum mean squared error (LMMSE) channel estimator. To improve the system convergence, we redefine the channel reliability factor by taking into account the channel estimation error statistics. Simulation results for rate 1/3 turbo code and two different normalized fading rates show that the use of the new reliability factor greatly improves the performance. The improvement is more substantial when channel statistics are unknown. K EYWORDS MAP-BCJR decoder, SNR, maximum Doppler frequency, turbo processing, channel reliability.

The Multi-Carrier Code Division Multiple Access (MC-CDMA) is becoming a very significant downlink multiple access technique for high-rate data transmission in the fourth generation wireless communication systems. By means of efficient resource allocation higher data rate i.e. throughput can be achieved. This paper evaluates the performance of group (subchannel) allocation criteria employed in downlink transmission, which results in throughput maximization. Proposed algorithm gives the modified technique of sub channel allocation in the downlink transmission of MC-CDMA systems. Simulation are carried out for all the three combining schemes, results shows that for the given power and BER proposed algorithm comparatively gives far better results .

This paper presents the modeling and simulation of the most innovative MIMO-VBLAST technique. Wireless communication has suffered from the fading problem ever since its first appearance in 1897, when Guglielmo Marconi transmitted a wireless signal to a ship in the English Channel. The following century witnessed the remarkable development of wireless communication, especially in the last decade. The capacity of traditional communication systems along with 1x1 antenna system would be very low because of multi path propagation within radio channels. The multi-path signals add up constructively or destructively at the receiver antenna to give a fluctuating signal, which can vary widely in amplitude and phase. When the amplitude of the signal experiences a low value it is termed fading and the capability of the wireless channel is severely limited. Several efforts into this direction have been carried out to make the radio channel more efficient and this has got remarkable progress. Efficient techniques, such as frequency reuse and OFDM, have been invented to increase the bandwidth efficiency; on the other hand, advances in coding techniques, such as Reed Solemn codes, Convolution codes and low density parity check (LDPC) codes make it possible to almost reach Shannon capacity the theoretical performance limit of the channel. However, the development of the techniques for a single channel has yet to catch up with the increasing demand for the capacity The most promising solution to combat this effect is to have antenna diversity scheme which can be implemented with many of ways such as BLAST structure, STBC coding technique, etc. With the implementation of antenna diversity i.e. MIMO, the capacity of the communication system as well as channel will increase in terms of improved error rate performance. Also with the implementation of BLAST structure the data rate of the communication can be enhanced at the same amount of bandwidth. Ultimately this paper concludes effect of MIMO-BLAST to provide array gain i.e high data rate for modern wireless scenario.

Residual self-interference (SI) cancellation in the digital baseband is an important problem in full-duplex (FD) communication systems. In this paper, we propose a new technique for estimating the SI and communication channels in a FD communication system, which is inspired from superimposed signalling. In our proposed technique, we add a constant real number to each constellation point of a conventional modulation constellation to yield asymmetric shifted modulation constellations with respect to the origin. We show mathematically that such constellations can be used for bandwidth efficient channel estimation without ambiguity. We propose an expectation maximization (EM) estimator for use with the asymmetric shifted modulation constellations. We derive a closed-form lower bound for the mean square error (MSE) of the channel estimation error, which allows us to find the minimum shift energy needed for accurate channel estimation in a given FD communication system. The simulation res...

We consider turbo equalization of ISI channels for the practically relevant case when neither channel state information nor SNR knowledge is perfect at the receive side. In particular, we investigate the influence of imperfect (uncertain) training information on the performance of several known SNR estimation algorithms. Numerical results indicate that uncertain training data causes an additional bias that may lead to a performance degradation. We propose a modified, adaptive SNR estimation algorithm with reduced bias in the low SNR regime.

The Multi-Carrier Code Division Multiple Access (MC-CDMA) is becoming a very significant downlink multiple access technique for high-rate data transmission in the fourth generation wireless communication systems. By means of efficient resource allocation higher data rate i.e. throughput can be achieved. This paper evaluates the performance of group (subchannel) allocation criteria employed in downlink transmission, which results in throughput maximization. Proposed algorithm gives the modified technique of sub channel allocation in the downlink transmission of MC-CDMA systems. Simulation are carried out for all the three combining schemes, results shows that for the given power and BER proposed algorithm comparatively gives far better results .

The Multi-Carrier Code Division Multiple Access (MC-CDMA) is becoming a very significant downlink multiple access technique for high-rate data transmission in the fourth generation wireless communication systems. By means of efficient resource allocation higher data rate i.e. throughput can be achieved. This paper evaluates the performance of group (subchannel) allocation criteria employed in downlink transmission, which results in throughput maximization. Proposed algorithm gives the modified technique of sub channel allocation in the downlink transmission of MC-CDMA systems. Simulation are carried out for all the three combining schemes, results shows that for the given power and BER proposed algorithm comparatively gives far better results .

Proper use of firing pattern vis-à-vis the blast requirements can provide optimal blast performance in terms of fragmentation, throw, wall control etc. This is largely attributed to the importance of firing burden in any blast round. By changing the firing patterns the firing burden, and, thereby the ratio of spacing to burden is also subject to change. Proper initiation timing is as important for fragmentation as the burden, spacing, sub drilling, stemming etc. Simultaneous initiation leads to the problems, such as, coarser fragmentation, blasting of a large number of holes at a given time which leads to the other problems. The present research study which was conducted in three limestone quarries where major problems such as of improper fragmentation, poor wall control, and poor heave characteristics of the muckpile were observed. Designed firing pattern was not able to provide the requisite fragmentation, and, even the throw. Modifications in firing pattern were implemented to obtain the required blast results.

Image mosaicing algorithm based on random corner method is proposed. An image mosaicing is a method of combining multiple photographic with overlapping fields of view to produce a segmented panorama of high resolution image. The output of image mosaic will be the combination of two input images. In this paper we are using three step image mosaic methods. The first step is taking two input images and finding out the corners in both the images, second step is removing out the false corner in both the images and then by using homography we find its matched corner pair and we get final output mosaic. The experimental results show the proposed algorithm produces an improvement in mosaic accuracy, efficiency and robustness.

Channel estimation algorithms have a key role in signal detection in MIMO-OFDM systems. In this system, the number of channel components which need to be estimated is much more than conventional SISO wireless systems. Consequently, the computational process of channel estimation is highly intensive. In addition, the high performance channel estimation algorithms mostly suffer from high computational complexity. In the other words, the system undergoes intensive computations if high performance efficiency is desired. However, there is an alternative solution to achieve both high performance efficiency and relatively low level of computational complexity. In this solution, high efficient channel estimation is firstly designed, and then it is simplified using alternative mathematical expressions. In this paper, Iterative channel estimation based on QR decomposition for MIMO-OFDM systems is proposed. From simulation results, the iterative QRD channel estimation algorithm can provide better mean-square-error and bit error rate performance than conventional methods.