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Open access

M. Lakshmanan, P.S. Mallick and L. Nithyanandan

Abstract

Time Domain Synchronous Orthogonal Frequency Division Multiple Access (TDS-OFDMA) is used in mobile broadband wireless access scheme in uplink transmission. This leads to multiple user interference due to timing offset and frequency offset. In this paper, the effect of timing offset and channel estimation in mobile broadband system is analysed. Time-space two dimensional structure is used in TDS-OFDMA and perfect sequence is used for guard interval to achieve perfect timing synchronization and channel estimation for each user. Simulations are performed for timing synchronization and channel estimation using perfect sequence under Urban channel, Indoor Office B channel and HIPER LAN-A channel. Simulation results show that the timing synchronization is achieved and channel estimation performance using perfect sequence is better than CAZAC and PN Sequences.

Open access

Lim Chun Keat, Asral Bahari Jambek and Uda Hashim

Abstract

The heart rate of a person is able to tell whether they are healthy. A heart-rate monitoring device is able to measure or record the heart rate of a person in real time, whether it is an electrocardiogram (ECG) or a photoplethysmogram (PPG). In this work, a microprocessor system loaded with a heart-rate monitoring algorithm is implemented. The microprocessor system is the Nios II processor system, which interfaces with an analogue-to-digital converter (ADC) and a pulse sensor. A beat-finding algorithm is used in the microprocessor system for heart rate measurement. An experiment is carried out to analyse the functionality of the microprocessor system loaded with the algorithm. The results show that the detected heart rate is in the range of the average human being’s heart rate. The signal flow within the microprocessor system is observed and analysed using SignalTap II from Quartus’ software. Based on a power analysis report, the proposed microprocessor system has a total power dissipation of around 218.26 mW.

Open access

Mohammad Yanuar H, Risanuri Hidayat and Eka Firmansyah

Abstract

LED driver has the potential to interfere the system of electronic devices if the voltage and current change rapidly. Several previous studies presented various solutions to overcome this problem such as particular converter design, component design, electromagnetic interference (EMI) filters, and spread-spectrum techniques. Compared to other solutions, the spread-spectrum technique is the most potential way to reduce the EMI in LED applications due to its limited cost-size-weight. In this paper, the effectiveness of conducted EMI suppression performance and the evaluation of its effect on LED luminance using spread-spectrum techniques are investigated. Spread-spectrum is applied to the system by modifying the switching frequency by providing disturbances at pin IADJ. The disorder is given in the form of four signals, namely square, filtered-square, triangular, and sine disturbance signals. The highest level of the EMI suppression of about 31.89% is achieved when the LED driver is given 800 mVpp filtered-square waveform. The highest reduction power level occurs at fundamental frequency reference, when it is given 700 mVpp square disruption signal, is about 81.77% reduction. The LED luminance level will reduce by 85.2% when it is given the four waveforms disruption signals. These reductions occur as the switching frequency of the LED driver does not work on a fixed frequency, but it varies in certain bands. LED brightness level has a tendency to generate a constant value of 235 lux when it is given the disruption signals. This disturbance signal causes the dimming function on the system that does not work properly.

Open access

Mousa Yousefi

Abstract

In this paper, analysis and design of colpitts oscillator with ability to transmit data at low output power with application in short-range wireless sensor networks such as MICS is described. Reducing the area required to implement the transmitter, on-chip implementation and appropriate energy efficiency are the advantages of this structure that makes it suitable for the design of short-range transmitter in biomedical applications. The proposed OOK transmitter works at 405 MHz with 10 Mbps data rate. Output power and total power consumption are 25 µW and 726 µW, respectively. Energy efficiency is 72.6 pJ/bit. The transmitter has been designed and simulated in 0.18 µm CMOS technology.

Open access

Ryszard S. Romaniuk

Abstract

Young Researchers Symposium WILGA on Photonics Applications and Web Engineering has been organized since 1998, two times a year. Subject area of the Wilga Symposium are advanced photonic and electronic systems in all aspects: theoretical, design and application, hardware and software, academic, scientific, research, development, commissioning and industrial, but also educational and development of research and technical staff. Each year, during the international Spring edition, the Wilga Symposium is attended by a few hundred young researchers, graduated M.Sc. students, Ph.D. students, young doctors, young research workers from the R&D institutions, universities, innovative firms, etc. Wilga, gathering through years the organization experience, has turned out to be a perfect relevant information exchange platform between young researchers from Poland with participation of international guests, all active in the research areas of electron and photon technologies, electronics, photonics, telecommunications, automation, robotics and information technology, but also technical physics. The paper summarizes the achievements of the 38th Spring Edition of 2016 WILGA Symposium, organized in Wilga Village Resort owned by Warsaw University of technology.

Open access

Marcin Jukiewicz and Anna Cysewska-Sobusiak

Abstract

The paper presents a process of stimuli design for SSVEP-based brain computer-interface. A brain computer-interface can be used in direct communication between a brain and a computer, without using muscles. This device is useful for paralyzed people to communicate with the surrounding environment. Design process should provide high accuracy recognition of presented stimuli and high user comfort. It is widely known how to make stimuli for BCI which are using high-grade EEG. Over recent years cheaper EEGs are becoming more and more popular, for example OpenBCI, which uses ADS1299 amplifier. In this article we review past works of other authors and compare it with our results, obtained using EEG mentioned before. We try to confirm that it is possible to use successfully OpenBCI in BCI projects.

Open access

Radosław O. Schoeneich and Rafał Surgiewicz

Abstract

Delay and Disruptive Tolerant Networks (DTN) are relatively a new networking concept that could provide a robust communication in wide range of implementations from the space to battlefield or other military usage. However in such dynamic networks, which could be considered as a set of intermittently connected nodes, message forwarding strategy is a key issue. Existing routing solutions concentrate mainly on two major routing families flooding and knowledge based algorithms. This paper presents SocialRouting - the social-based routing algorithm designed for DTN. The use of the social properties of wireless mobile nodes is the novel way of message routing that is based on message ferrying between separated parts of the network. Proposed idea has been extensively tested using simulation tools. The simulations were made based on especially designed for measurements in DTN scenarios and compared with popular solutions.

Open access

Jiliang Zhang, Hong Jiang and Gaofeng Pan

Abstract

In Rician-fading scenario, cognitive radio networks (CRNs) with a source in a secondary system transmitting its confidential information to a legitimate destination in the presence of an eavesdropper, are considered in this paper. Under CRNs, the interference power reaching at primary user (PU) is limited by some pre-defined threshold. Secrecy outage not only occurs when the achievable secrecy capacity for source-destination link is smaller than a target rate, but also occurs in the case that the interference power at PU is greater than that threshold. Analytical expression for secrecy outage probability has been derived and verified with simulation results. In addition, we have also derived the analytical expression for probability of non-zero secrecy capacity.

Open access

Radosław O. Schoeneich and Patryk Sutkowski

Abstract

At this moment there is a lack of research respecting Mobile Ad-hoc Networks (MANET) address assignment methods used in Delay Tolerant Networks (DTN). The goal of this paper is to review the SDAD, WDAD and Buddy methods of IP address assignment known from MANET in difficult environment of Delay and Disruptive Tolerant Networks. Our research allows us for estimating the effectiveness of the chosen solution and, therefore, to choose the most suitable one for specified conditions. As a part of the work we have created a tool which allows to compare these methods in terms of capability of solving address conflicts and network load. Our simulator was created from scratch in Java programming language in such a manner, that implementation of new features and improvements in the future will be as convenient as possible.

Open access

V. Leela Rani and M. Madhavi Latha

Abstract

Leakage power is the dominant source of power dissipation in nanometer technology. As per the International Technology Roadmap for Semiconductors (ITRS) static power dominates dynamic power with the advancement in technology. One of the well-known techniques used for leakage reduction is Input Vector Control (IVC). Due to stacking effect in IVC, it gives less leakage for the Minimum Leakage Vector (MLV) applied at inputs of test circuit. This paper introduces Particle Swarm Optimization (PSO) algorithm to the field of VLSI to find minimum leakage vector. Another optimization algorithm called Genetic algorithm (GA) is also implemented to search MLV and compared with PSO in terms of number of iterations. The proposed approach is validated by simulating few test circuits. Both GA and PSO algorithms are implemented in Verilog HDL and the simulations are carried out using Xilinx 9.2i. From the simulation results it is found that PSO based approach is best in finding MLV compared to Genetic based implementation as PSO technique uses less runtime compared to GA. To the best of the author’s knowledge PSO algorithm is used in IVC technique to optimize power for the first time and it is quite successful in searching MLV.