G. Mohiuddin Bhat

A high capacity data hiding scheme based on edge detection and even-odd plane separation

In this paper a high capacity data hiding technique based on hybrid edge detection and even-odd pixel separation is proposed. The even-odd sub planes of Red, Green and Blue of the cover image are extracted then Blue and Green channel sub planes are utilized for hiding the secret data while Red channel sub planes are used to hold the status (edge or non-edge) of the pixels of Green and Blue channel sub planes. The experimentation has been carried out for different capacities of data bits and the results are compared with a state of art data hiding technique which reveals that the proposed technique has high capacity. Further good quality stego-images are obtained.

PAPR reduction in MIMO-OFDM system using combination of OSTBC Encoder and Spreading code sequence

Orthogonal Frequency Division Multiplexing (OFDM) is regarded as one of the most outstanding multicarrier modulation technique in fourth generation (4G) wireless networks, which makes it possible to transfer very high bit rates despite extensive multipath radio propagation (echoes). The use of smart antenna arrays both at transmitter and receiver further increases the bit rate and enhance the system diversity on time variant and frequency selective channels resulting in a multiple-input multiple-output (MIMO) configuration. However one of the main disadvantages associated with MIMO-OFDM is the high Peak-to-Average Power Ratio (PAPR) of the transmitters output signal on different antennas. High Peak to Average Power Ratio (PAPR) for MIMO-OFDM system is still a demanding area and difficult issue. So far numerous techniques based on PAPR reduction have been proposed. In this paper a new method based on the combination of OSTBC Encoder and Spreading code sequence have been implemented and simulated. The results obtained are compared with earlier results based on transform techniques. Simulations show that better results are obtained in proposed technique.

Towards Green Capacity in Massive Mimo Based 4G-LTE a Cell Using Beam-Forming Vector Based Sectored Relay Planning

In this information age, high data rates and good reliability features are becoming the dominant factors for a successful deployment of commercial networks. Increasing capacity with finite power requirement in wireless networks is one of the main challenges for high speed communications. A new method of power allocation in wireless communication using beamforming vector based sectored relay planning for capacity enhancement has been proposed. It has been observed that any number of terminals (receive antennas) in the downlink can be incorporated without the requirement of additional link budget. Moreover, it has also been observed in the proposed technique that required power is also independent of coverage area i.e., the channel losses at cell borders. This optimal power allocation has been observed using beamforming vector. The beamforming vector becomes independent of transmitter diversity and is the function of receive antennas on both wireless backhaul and access link (sampled impulse response). The target signal-to-interference-noise-ratio (SINR) in the proposed technique can be achieved at small and finite power; therefore any capacity can be achieved at the target SINR. This is in contradiction to the major outcomes of the Shannon’s theorem. The simulations have been carried out in Matlab and the results given in the form of various plots and graphs.

Compression and denoising of speech transmission using Daubechies wavelet family

Over the past few years there has been much work done on compression and enhancement of speech signals. Efficient speech compression techniques are becoming hectic with the fast growth of data and multimedia services. In this paper, wavelet-based analysis, processing and compression of multimedia signals like speech are described and implemented. A wavelet-based speech compression and speech denoising techniques obtained by using hard and soft thresholding algorithm are presented. Daubechies wavelets have been implemented on a test recorded speech signal for compression and denoising purposes. It has been found that the proposed work shows better results as compared to the already existing technique. Moreover, soft thresholding is preferable over hard thresholding with higher PSNR and less MSE. The results obtained have been found satisfactory as compared to existing state-of-the-art techniques.

Light weight Authentication Framework for WSN

Primarily deployed for monitoring environmental parameters, WSN are now finding increased use in commercial, domestic, military and health applications. There deployment in hostile terrains and for mission critical applications touching human lives call for addressing their security issue. Especially under IoT and smart city projects like Padova Smart City project, the range of applications envisioned to be developed, would be tightly coupled to the physical world where security aspects would be paramount. This paper presents a light weight Authentication Framework which supports node registration, entity authentication, key establishment, new node injection and broadcast authentication of messages diffusing from base towards nodes in WSN. The solution leverages the low computational overheads associated with cryptographically secure one-way hash chains and ECC without using any digital signature algorithm. The usage of hidden generator point derived by using hash-chains provides defence against man-in-the middle attack a prominent feature in ECDH. The proposed framework is compared with other similar Schemes like Novel Access Control Protocol for secure Sensor Networks (NACP).

A new multiple input multiple output multi-carrier direct sequence code division multiple access system using T × T spreading with link budget analysis

High data rates and High Quality of Service QOS are the main requirements in Next Generation Networks NGNs. The communication channel needs to be shared in an efficient manner. An interesting technique is based on spread spectrum and orthogonal coding sequence called Code Division Multiple Access CDMA. Owing to performance and implementation complexity issues, multi-user detection methods are mainly restricted in high data transmission rate CDMA. In this paper, a low complex multi-user Multi-Carrier CDMA MC-CDMA receiver is proposed and implemented, which employs time T domain spreading at both coding and modulation ends and consequently increases the processing gain. The performance comparison of the proposed technique and the conventional schemes has been performed in terms of bit error rate. The results of the link budget analysis have been provided in terms of reports generated by link budget software of Bonsai Networks.

On the design and performance evaluation of compressed speech transmission over wireless channel

Wireless Transmission of a speech signal with low Bit Error Rate is one of the major challenges in Communication Systems particularly in cellular environment. In this paper a new technique to evaluate the performance of coded speech at a low data rates using Linear Predictive Coding (LPC) and Quadrature Phase Shift Keying (QPSK) modulation has been realized and simulated. A test recorded speech signal is compressed using Linear Predictive Coding and transmitted using QPSK modulation. We compare the performance of a speech signal compressed with LPC with that compressed with LPC and modulated using QPSK. It is found that the performance of the speech signal with LPC and QPSK modulation outperforms the other technique. The performance has been evaluated using Mean Square Error (MSE), Peak Signal to Noise Ratio (PSNR) Compression Ratio (CR) and Bit Error Rate (BER). The proposed scheme will serve as a useful tool for simulating the transmission of a compressed speech signal.

Orthogonal Variable Spreading Factor (OVSF) based image transmission using Multiple Input Multiple Output Orthogonal Frequency Division Multiplexing (MIMO-OFDM) system

Orthogonal Frequency Division Multiplexing (OFDM) in combination with Multiple Input Multiple Output (MIMO) is a popular method for high data rate wireless transmission. The use of multiple antennas at both sides of the link offers an additional fundamental gain-spatial multiplexing gain, which results in increased spectral efficiency. This paper is concerned with the simulation, modeling and performance evaluation of Multiple Input Multiple Output Orthogonal Frequency Division Multiplexing (MIMO-OFDM) with improved performance. In this scheme OVSF codes have been used for image spreading before transmission as it solves the synchronization problem and minimizes the effect of unwanted noise during transmission. Rayleigh fading channel has been used in the proposed scheme. The performance of the proposed scheme has been tested on image signal and checked by waveforms and plots by calculating bit error rate and pixel error rate. Various digital modulation techniques have been used for checking the performance of the proposed scheme.

On the Design and Realization of Non-Synchronous Frequency Hopping Spread Spectrum for Securing Data over Mobile and Computer Networks

We propose and investigated the novel scheme of non-synchronous method of Frequency Hopping Spread Spectrum modulation and demodulation scheme. The frequency hopping spread spectrum is most widely used spread spectrum technique in wideband wireless communications due to its numerous advantages like elimination of near far effect in cellular mobile communications. The strict timing synchronization is major requirement in frequency hopping spread spectrum. The hopping pattern at transmitting as well as receiving end should be synchronous to each other. This can be achieved to use same spreading codes both at transmitting and receiving end. In practical communication systems it is very difficult to achieve code synchronization when the signal is supposed to transmit over frequency selective channels. In this paper a novel scheme has been proposed in which two Frequency Modulation (FM) demodulators (CXA1619BS) one at transmitting end and another at receiving end have been used to produce voice signal having same frequency and amplitude, due to random behavior of voice signal ( only unvoiced part was taken) a chaotic signal was generated and used as spreading code. The digitally controlled chaos oscillator has been used for spreading code generation. Since in two different geographical regions FM signals received at transmitting as well as receiving end at the same time are having same frequency and amplitude, therefore do not require synchronous codes for proper detection of received data. So the proposed technique solves one of the major problems of synchronization in practical communication systems. The proposed scheme was tested experimentally using hardware module and results are presented in the form of various waveforms.

CPLD based power management system for low power devices

Energy is a precious resource in Wireless Sensor Nodes. With each transmission/reception and computation, energy is being expended and batteries get drained which can result in premature death of nodes and thereby reduced life span of WSN. The problem gets critical when the network is implemented under harsh environmental conditions like forests. Thus energy harvesting from environment becomes an important concern. In this paper, a design is presented for the development of power management system in an energy constraint device like wireless sensor node. The design presented utilizes solar energy to improve the efficiency and extend the duration of operation for sensor nodes. Experimental setup comprises of a PV based array simulator and a CPLD based power management module.