فهرست مطالب

Majlesi Journal of Telecommunication Devices
Volume:7 Issue: 2, Jun 2018

  • تاریخ انتشار: 1397/03/18
  • تعداد عناوین: 6
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  • Aarti Sangwan, Partha Pratim Bhattacharya Page 33
    A Wireless Body Area Network (WBAN) is capable of performing autonomous sensing of physiological signals of the human body without interrupting their normal activities. It consists of various intelligent, miniature and low power bio-sensor nodes placed on or in the close proximity of the human body. Routing in WBANs is a major issue as the reliability of a network depends on routing. Complex structure and mobile nature of human body are the main obstacles while designing routing protocols for WBANs. In this work, we have revised the performance of EECBSR (Even Energy Consumption and Back Side Routing) protocol by selecting a forwarder node with minimum cost function. Minimum distance of nodes from sink, residual energies of individual nodes and the total residual energy of the network are used to formulate the cost function in Revised-EECBSR. Sensor nodes are deployed on front side and as well as back side on the human body. Results show that REVISED-EECBSR performs better in terms of throughput, path loss, delay and network's stability than existing EECBSR protocol.
    Keywords: Energy efficient, routing, EECBSR, WBAN, reliability, path loss, delay
  • Mehdi Khatir * Page 41
    This study was carried out to design, simulate, and develop an ultra wideband (UWB) fractal microstrip patch antenna (MPA). The antenna designed for broadband telecommunications had smaller dimensions, omnidirectional pattern, and good gain/return loss. The miniaturization was realized through a metamaterial transmission line and antenna power supply by an electromagnetic coupling system. In order to cover the desired frequency bandwidth, a new fractal was designed and combined with the circular polarization of disturbances in certain parts of the fractal structure. Furthermore, the quality of antenna bandwidth was improved deforming the ground plane. Finally, the results of the development, simulation, and measurement of input return losses and radiation patterns were explored. The results demonstrated that the proposed model involves a compact, simple fractal MPA that provides ideal bandwidth and impedance matching.
    Keywords: Fractal Microstrip, Metamaterial, Circular polarization
  • Mojdeh Mahdavi, Mohammad Amin Amiri Page 47
    Dependability of a circuit is among the most important issues in the design process and reliability concerns are associated with the digital system design. A fault tolerant system should have the ability to detect, locate and correct the error and recover the system to normal operational conditions. It is more important to use fault tolerant gates in nano scale digital circuits because by decreasing the device dimensions the influence of external factors and therefore the probability of fault occurrence will increase. Since the binary wire is an essential part of digital systems and especially QCA (Quantum Cellular Automata) circuits, a redundancy based fault tolerant technique is presented in this paper to improve the fault tolerance of this part. The efficiency of this method is evaluated by MATLAB software. Results show that the fault tolerance of binary wire will significantly increase by using the proposed method. The hardware redundancy of this method is about 100% which is much less than TMR (Triple Module Redundancy) methods by more than 200% redundancy.
  • Mohsen Vahabi, Amir Sabbagh Molahosseini Page 53
    The conventional CMOS technology faces different challenges such as fabrication in nanoscale which motivates researchers to find new alternatives to it for future high-performance systems. The quantum-dot cellular automata (QCA) is one of efficient nano-electronics technologies which can provide simple and efficient implementation of digital circuits in nanoscale. Due to the importance of addition in digital processors and embedded systems, there many QCA designs of adders and subtractors during the previous years. However, recently the unified design of adder and subtractor circuits has been considered to achieve overall area and delay reduction for digital computational circuits. In this paper, we present new coplanar design of a unified adder/subtractor unit with the QCA technology. Besides, the proposed single-layer design approach has been used to design separate half adder, half subtractor, half adder and full adder circuits. The comparison of circuit’s parameters of the proposed designs than previous works show the significant improvement in term of area, delay and cell number.
    Keywords: Keywords: Quantum, dot Cellular Automata, Full Adder, Subtractor, coplanar (single layer)
  • Ghazal Moradi, Mohammad Reza Alamdar, Saber Izadpanah Tous Page 65
    In this paper a new hybrid frequency compensation (HFC) technique consists of indirect compensation and compensation using unbalanced differential pairs for low-voltage low-power CMOS operational amplifiers (op amp) is proposed. This technique significantly improves frequency response of the op amp and avoids instability when a large capacitive load at the output of the op amp must be handled. Also, Dynamic threshold voltage MOSFET (DTMOS) and sub-threshold region are utilized in the design to effectively use the low supply voltage and reduce power consumption. To evaluate the proposed technique, the two stage operational amplifier is designed and simulated in a TSMC 0.18 μm CMOS process technology. The op amp operate at 0.6 V power supply with 138.3 nW power consumption. The proposed HFC technique uses a total compensation capacitance of 3.5 pF and is robust in stability under the variation of the load capacitance between 0 pF and 100 pF. When driving a 15 pF load, the proposed HFC amplifier reduces the total capacitor size 35% and improves the unity-gain bandwidth 481% compared to the conventional Miller compensation.
    Keywords: op amp, low, voltage low, power, hybrid frequency compensation, indirect compensation, unbalanced differential pair
  • Parisa Alinezhad, Farhad Mesrinezhad, Hossein Emami Page 73
    Given the needs of today's world, quick, high-volume, and high quality communication of information is performed in a variety of ways. Studies conducted by the researchers in the field of routing and wavelength allocation algorithms in previous years show that these algorithms have greatly improved the performance of communication and information transmission. However, these topics have been largely investigated, but in particular, in the optical networks WDM, is one of the goals of the routing problem investigation, wavelength allocation, and maximizing useful communication. In other words, because the optical route in the WDM optical network is the connection between the receiver node and the transmitter node, the best route for the network should be considered. As we mentioned, these issues have largely been investigated over the past years, but still the issue of RWA is presented and examined as a major and challenging issue.In this article, we offer a new way for weighting-based routing for all the optical channels. This selective weighting method dramatically reduces the possibility of blocking communications. Another issue we have addressed in this article is conditions where traffic is dynamic. According to the results obtained, it is shown that performance has been improved compared to the previous modes.