Manjit Singh Bhamrah

Capacity in fading environment based on soft sensing information under spectrum sharing constraints

In this paper, the ergodic channel capacity for a secondary user is investigated using soft sensing information about primary user activity in a shared channel under joint peak transmit power and average received interference power constraints for Nakagami-m fading channel. The results of the proposed power adaptation scheme illustrate the effect of communication environment parameters and soft sensing information about primary user activity on the channel capacity of secondary user. In particular, the effect of cross link channel state information to maximize the channel capacity for the power adaptation scheme is emphasized by considering the Lagrangian optimization problem for joint peak transmit power and average interference power constraints. Moreover, the performance of the primary user is also investigated considering the interference of the secondary user to the primary in spectrum sharing environment in terms of transmission rate and average channel capacity.

Analytical Modeling of Ad Hoc Cognitive Radio Environment for Optimum Power Control

Radio is an emerging wireless technology that has grabbed the attention of researchers, academicians, and telecommunication industries worldwide. Recent survey reports show that unlicensed frequency bands have become overcrowded from past few years with widespread acceptance of diverse wireless technology applications whereas, licensed frequency bands are being used intermittently. To deal with the conflicts between unlicensed spectrum overuse and underutilization of licensed frequency band, Cognitive Radio technology has been evolved eventually. It allows unlicensed subscribers to access licensed subscriber frequency band with some power constraints such that minimum or no interference should be experienced by primary user and its quality of service should not be affected while sharing its spectrum with unlicensed secondary subscriber. In this paper, distance based power control scheme has been analyzed for overlay ad-hoc cognitive radio network. It is shown that algorithm provides optimum power control as long as the separation between cognitive transmitter and receiver is greater than or equals to maximum decodable radius of primary transmitter. Keywordscommunication commission (FCC), Primary user (PU), secondary User (SU), Quality of services (QoS), Cognitive Radio (CR).

Rate and Power Optimization Under Received-Power Constraints for Opportunistic Spectrum-Sharing Communication

In this paper, the channel capacity of secondary user is investigated for opportunistic spectrum sharing with primary user in a Rayleigh fading environment. In the proposed communication scenario, on finding transmission opportunities in licensed band, secondary user utilizes the band as long as the interference power inflicted on primary receiver is below the predefined threshold, and adjusts its transmission power and data rate based on the sensing information available from spectrum sensor. In this context, two different adaptation schemes namely adaptive transmission power scheme and adaptive rate and transmission power scheme are investigated under joint peak and average received power constraints at primary receiver for multilevel quadrature amplitude modulation format. The closed form expressions are derived for the ergodic channel capacities of these schemes and numerical results are presented to validate the theoretical results. Moreover, a comparison between channel capacities is given to illustrate the benefit of using soft sensing information under said constraints.

The identification of liver cirrhosis with modified LBP grayscaling and Otsu binarization

Liver cirrhosis is considered as one of the most common diseases in healthcare. The widely accepted technology for the diagnosis of liver cirrhosis is via ultrasound imaging. This paper presents a technique for detecting the cirrhosis of liver through ultrasound images. The region of interest has been selected from these ultrasound images and endorsed from a radiologist. The identification of liver cirrhosis is finally detected through modified local binary pattern and OTSU methods. Experimental results from the proposed method demonstrated its feasibility and applicability for high performance cirrhotic liver identification.

Adaptive Power Control Scheme for the Cognitive Radio System Based on Receiver Sensitivity

Cognitive radio has been proposed as the most promising technology to overcome the spectrum scarcity problem by exploiting the vacant frequency band of assigned licensed spectra; though some tradeoffs exist to protect the licensed primary user communication and to enhance the throughput of unlicensed secondary cognitive user. Through spectrum sensing and power control scheme, this issue can be addressed well as it allows the cognitive user to access the licensed band when primary user is not using it. In most of the previous works, it has been assumed that for transmission power control, perfect channel state information is available beforehand to the cognitive transmitter. This assumption does not hold good in practical scenarios and moreover it is difficult to implement spectrum sensing in device. To address this issue, a sensing free power control scheme based on CR receiver sensitivity is proposed in this paper. It allows cognitive user to controls its transmission power adaptively by approximating the distance from primary through cognitive receiver sensitivity. Simulation results are presented to verify the theoretical analysis.

Influence of Initial Energy Selection in Leach Protocol based Wireless Sensor Networks

The paper investigates the change of initial energy in leach protocol to prolong the network lifetime in order to achieve network reliability and scalability. The values of initial energy taken are 0.5, 1, 2, 3 joule. For the case, simulation results show that nodes start decaying after 5100 rounds. Thus nodes are surviving longer for higher energy cases taken. The work recommends adequate energy use to increase network lifetime of Wireless Sensor Networks. Key words-Wireless Sensor Network, Leach Protocol, Clustering, Network Lifetime

Performance analysis of distributed fiber Raman amplifiers employing higher order pumping schemes in optical transmission systems

Performance of fiber Raman amplifier is explored with special emphasis on higher order pumping configurations for wavelength division multiplexed optical transmission systems. The amplification analysis is done in terms of equivalent noise figure (ENF), optical signal-to-noise ratio (OSNR), and double Rayleigh backscattering (DRBS) noise powers. The investigations reveal that at 36 dB on–off gain, ENF improvement of 1 dB (using second order pumping) and of 2 dB (using third order pumping configuration) can be achieved. On similar lines, by varying input optical power and fiber length, OSNR and DRBS are reported for the higher order of pumping configurations. Overall, the work presents improvements of about 1 dB in ENF and 0.03 dB in OSNR. These investigations are produced at lower input signal powers.

Texture Analysis of Ultrasound Images of Liver Cirrhosis Through New Indexes

In health care, one of the most regular diseases is considered that is liver cirrhosis. The mostly accepted method in the identification of liver cirrhosis is by use of ultrasonic images. In this research paper, a method is proposed for identifying the cirrhotic liver through images of ultrasound. The portion of interest has extracted in the cirrhotic and normal ultrasonic images and approved through a radiologist. The cirrhotic liver’s recognition is discriminated through new two indexes, i.e., area index and ratio index. The results from the projected new indexes verified its practicability and applicability for recognition of cirrhotic liver.

Analysis of Dual-Order Backward Pumping Schemes in Distributed Raman Amplification System

Abstract Backward pumping in fiber Raman amplifiers has been investigated in this paper in terms of on-off Raman gain, noise figure and optical signal-to-noise ratio. The results exhibit that with four first-order pumps and one second-order pump scheme can be employed to achieve 8.2 dB noise figure in 64 channel fiber optic communication system. It has also been reported that 2.65 dB gain ripple, 0.87 dB noise figure tilt and 2.02 dB OSNR tilt can be attained with the second-order pumping in fiber Raman amplifiers. The main advantage of the scheme is that only 50 mW second-order pump shows appreciable improvement in the system performance. It shows that further increase in first-order and second-order pump powers increase system noise implications.

An optimal scheduling and routing under adaptive spectrum-matching framework for MIMO systems

ABSTRACT Multi-users (MUs) along the communication links cause noise and traffic in the channel. The prediction of availability and the optimal usage of channels are the main objectives of the multi-input multi-output (MIMO) system. Several optimisation algorithms select the optimal channel for the users effectively. But the high-error rate and the probability values are the two major problems in traditionally optimised channel selection methods. The bandwidth allotted for information transmission is minimum. Moreover, the outage probability values are maximum in traditional scheduling algorithms. This paper proposes the new optimisation algorithm that predicts the channels for transmission and adaptive spectrum matching concept to predict the suitable channel from allocated bands. Also, the prioritisation on high-spectrum intensity basis assures an efficient data delivery to the receiver. The scheduling of available channels and data prioritisation minimises the error probability rates. This paper investigates the effectiveness of proposed optimal channel utilisation against the different modulation schemes such as three-dimensional complementary codes, linear network coding with the quadrature phase shift keying in terms of the average block error probability and bit error rate.