Mirza Tariq Beg

Analysis of different techniques for low power Single Edge Triggered Flip Flops

In this paper, we compared various different techniques of previously published Single Edge Triggered Flip Flops (SET FFs). Flip Flops are most essential elements in the design of sequential circuits. We did the comparison for their performance and power dissipation and have also compared the transistor count of each Flip Flop.

2 GHz low power double edge triggered flip-flop in 65nm CMOS technology

This paper proposed a low power, Double-edge-triggered flip-flop design in 65nm CMOS technology. The proposed DETFF is having fewer clocked transistors than earlier conventional designs. The DETFF is simulated with different clock frequencies ranging from 400MHz to 2GHz. Simulation results show least delay, lowest power dissipation than older designs. Further, at scaled voltages the average power dissipation is improved by 46.85% and 96.60% when compared with DETFF1 and DETFF2 respectively and improvement in PDP is 58% and 97.54% as compared to DETFF1 and DETFF2 respectively, which claims that proposed design is suitable for low power, low voltage and high speed applications.

Performance analysis of STBC encoded cooperative MIMO system for wireless sensor networks

Wireless sensor networks consist of sensor nodes with sensing and communication capabilities. As sensor nodes are generally battery-powered devices, the critical aspects to face concern how to reduce the energy consumption of nodes, so that the network life time can be increased to reasonable times. The efficiency of space-time block code-encoded (STBC) cooperative transmission is studied. An energy-efficient virtual multiple-input multiple-output (MEMO) communication architecture based on V-BLAST receiver processing is proposed for energy-constrained, distributed wireless sensor networks. Numerical results show that significant energy saving are offered by the proposed virtual MEMO architecture in distributed wireless sensor networks. Cooperation protocol with low overhead is proposed, and synchronization requirements among cooperating sensors are discussed. Energy efficiency is analyzed as a trade-off between the reduced transmission energy consumption and the increased electronic and overhead energy consumption. Simulations show that with proper design, cooperative transmission can enhance energy efficiency and prolong sensor network lifetime. Simulation results are included.

Bouncy Detector to Differentiate between GSM and WiMAX Signals

This work considered the differentiation and discrimination between GSM and WiMAX signals in noisy environment. Our new discriminator (Bouncy Detector (BD)) is an extension of the work of Hop Rate Detector (HRD) and it is exploited for differentiation and discrimination process between GSM and WiMAX signals. HRD was basically designed to detect and estimate the hop rate of frequency hopping signals only. Other kind of detectors like Matched Filter detector, Energy Detector and Feature Detector cannot give us an indication about the type of signals and also suffer from many drawbacks like complexity in design, determining the value of threshold level and increasing probability of false alarm (Pf) in high noise level etc. The simulation results show that BD can work properly and accurately without confusion between the signals, even in highly noise environment.

Structure based calculation for scanned field enhancement factor for CNT field emitters

The screening effect plays an important role when CNTs are placed in clustered and also have large effects in the calculation of field enhancement factor of clustered CNTs. Isolated CNT will have a greater field enhancement factor than the field enhancement factor cluster of CNTs because of screening effect. The screening effect is a function of distance between CNTs and length of CNTs. By using the expression for the field enhancement factor (β) of CNTs in cluster (under any position), we have proposed a structure for cluster of CNTs in lieu to get the uniform field enhancement factor of all the CNTs present in that cluster.

Resource allocation algorithms in LTE: A comparative analysis

As a breakthrough technology under 3GPP, LTE has attracted attention worldwide. Main features include enhanced peak data rates, lower delay, increased cell edge throughput. For an LTE system, serving a large number of users requires an efficient RRA algorithm which has not been standardized for the system and is still an open end for development. Researchers have proposed various algorithms some of which have become popular among network designers. A comparative study of some of these popular RRA algorithms has been carried out in this paper.

Improve the Performance of Cooperative Spectrum Sensing Using Hopping Sequence Scheme

A significant impact on the spectrum efficiency and quality of service (QoS) of a secondary user (SU) is the ability to capture a frequency slot for transmission in an idle channel. Hence, the SU needs to sense the related spectrum in order to classify a licensed frequency band as occupied or vacant. Spectrum sensing can be a demanding task for a single user due to the random nature of the wireless channel and networks. Cooperative sensing by eight SU nodes have been proposed in this paper to mitigate the effects of channel fading and try to detect the presence/absence of two primary users (PUs). A sensing policy for coordinating the cooperative process is proposed based on two levels hierarchical-fuzzy logic system (H-FLS) by adding a Hopping Sequence (HS) module to the detectors. Two hopping methods are proposed, Random Hopping (RA-H) and Sequential Hopping (SE-H). The simulation results shows enhancement in probability of detection over conventional cooperative sensing.

The Exploitation of Unused Spectrum for Different Signal’s Technologies

Technological advances and market developments in the wireless communication area have been astonishing during the last decade and the mobile communication sector will continue to be one of the most dynamic technological drivers within comparative industries. This paper extend our previous work for detection and discrimination signals, and deals with a cognitive radio system (CR) to improve spectral efficiency for three signals (WiMAX, Frequency Hopping and CDMA2000) by sensing the environment and then filling the discovered gaps of unused licensed spectrum with their own transmissions. We mainly focused on energy detector spectrum sensing algorithm. The simulation shows that the CR systems can work efficiently by sensing and adapting the environment, and showing its ability to fill in the spectrum holes then serve its users without causing harmful interference to the licensed user.

Overview of Optical Techniques for Characterization of High-Power Infrared Gas Lasers

High-power lasers typically form a multidisciplinary technological area laced with innumerable challenges in its realization as a practical system. The prime amongst them are infrared gas laser sources, such as carbon dioxide gas dynamic laser, hydrogen fluoride, deuterium fluoride laser, and chemical oxygen iodine laser. Each of these laser systems is associated with a unique as well as complex active medium environment involving intense interaction between lasing and pumping species under specific gas dynamic conditions. The parameters viz., specie concentration of the lasing, pumping mediums and other by-products, medium homogeneity, individual constituent gas flow rate, pressure and temperature at critical locations, and cavity Mach number are very crucial in determining the output of the gas laser system. It is essential to determine these parameters nonintrusively, with necessary precision so as to optimize these lasers especially in case of large-scale systems. Thus, the focus of this paper is to review and discuss the existing applicable optical detection methodologies ranging from the more established methods, such as optical absorption/emission spectroscopy, to very contemporary, such as Raman spectroscopy, cavity ring down spectroscopy, laser-induced fluorescence/planer laser-induced fluorescence, and so on, which are relevant for the diagnostic needs of gas lasers.

Differentiation and discrimination between GSM and WiMAX signal's technologies

One of the most challenging topics for next - generation wireless networks is the process of discrimination among signals, since many of wireless technologies overlap each other and build a heterogeneous topology. The conventional signals detection methods like Matched Filter detector, Energy Detector and Feature Detector cannot give us an indication about the type of signals. Also suffer from many drawbacks like complexity in design, determining the value of threshold level and increasing probability of false alarm (Pf) in high noise level etc. This work considered the differentiation and discrimination between GSM and WiMAX signals in noisy environment. Our discriminator (Bouncy Detector (BD)) is an extension for Hop Rate Detectors (HRD). It was basically designed to detect and estimate the hop rate of frequency hopping signals only. The simulation results show that BD can work properly and accurately without confusion between the signals even in highly noise environment.