Browsing by Author "Kunagorn Kunavut"
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    Adaptive Location Update Schemes for Continuous Cell Zooming Algorithm in Wireless Networks
    ( 2015) Tun, Khin Cho ; Kunagorn Kunavut
    Continuous cell zooming algorithm is a potential dynamic cell zooming algorithm for energy-efficient operation of mobile wireless networks. In this algorithm, location management strategy (location update process) is required to know the location of the farthest user in each cell to perform cell zooming. However, the application of conventional periodic update scheme in continuous cell zooming algorithm can lead to a high signaling cost. Therefore, in this paper, two adaptive location update schemes, namely, Time-Adaptive Periodic Update (TAPU) and Location-Adaptive Periodic Update (LAPU) are proposed aiming to reduce the number of update messages in continuous cell zooming operation. The performances of the proposed adaptive location update schemes are compared with that of Convention Periodic Update (CPU) scheme. Their performances are evaluated in terms of power saving capability, outage ratio and number of update messages raised in cell zooming operation in both omni-directional and sector-based cell networks. The TAPU and LAPU have no significant effect on power saving capability of continuous cell zooming algorithm and they give less number of update messages compared to CPU scheme. However, outage occurs in cell zooming operation with TAPU scheme because it has longer update intervals. Meanwhile the LAPU scheme can eliminate outage in cell zooming operation as CPU scheme does.
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    The Effect of Transmission Range in Multi-hop Wireless Networks
    ( 2014) Kunagorn Kunavut
    Transmission or communication range is an important factor for successful data delivery in wireless communications including multi-hop wireless networks. Typically, transmission range can be technically adjustable by configuring the transmitting power (Tx Power) or changing the antenna height. For the same antenna height, if transmission range is minimized or adjusted to be shorter by lowering Tx power, there is less energy consumption but the networks are likely to be unconnected which consequently degrades the network performance such as throughput and delivery ratio. In the case that range of nodes is maximized or extended for connectivity by increasing Tx power, networks become connected and a node may reach the others by using just a hop. This beneficially affects network performance but these nodes with range extension consume more energy for data transmission. Hence, there is trade-off between energy consumption and network performance when adjusting transmission range. In addition, in multi-hop wireless networks where nodes are usually mobile and network topology are highly dynamic, transmission range has lots of impact on network performance. Hence, to study the effect of transmission range is very important and required. In this work, various scenarios (i.e. load-, speed- and density-varying scenarios) are constructed to investigate both energy consumption and network performance with different transmission ranges.
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    Energy Efficient Topology Control in Multi-hop Wireless Networks based on One-hop and Two-hop Neighbor Information
    ( 2016-07) Maw, Min Min Thet ; Kunagorn Kunavut
    Topology control in multi-hop wireless networks is a technique used to control nodes' activities to construct a topology with an acceptable level of network connectivity while minimizing energy consumption. It can be broadly classified into two main paradigms which are State Scheduling and Transmission Power Control. Both of them have received lots of attention from many researchers for decades. According to Transmission Power Control technique, most of them take into account only one-hop neighbor information to optimize transmission power and control topology in multi-hop wireless networks. In this paper, an energy efficient topology control based on both one-hop and two-hop neighbor information is proposed to reduce energy consumption without degrading network performances. A number of simulation scenarios are constructed in this work to study energy consumption as well as other network performances that are endto- end delay, throughput, and packet delivery ratio of the proposed algorithm.
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    A Novel Adaptive Topology Control in Mobile Ad Hoc Networks based on Connectivity Index
    ( 2015-11) Kunagorn Kunavut
    Mobile ad hoc networks or MANETs are infrastructureless wireless networks where each node can freely move and directly connect to the other nodes located within its transmission range to form the topology in any arbitrary pattern. Hence, to ensure network connectivity, each node tends to use the maximum transmission power to extend its transmission range. However, this maximized transmission range typically consumes more energy and consequently drains battery faster on mobile devices in these networks. Topology control is an effective technique proposed in ad hoc networks to ensure network connectivity while reducing energy consumption to prolong operation lifetime. In this work, a novel technique is proposed for an adaptive topology control to allow each node to optimize its transmission range while obtaining the compromising level of network connectivity. This novel topology control can be effectively carried out by allowing nodes to maintain the predefined value of Connectivity Index (CI) which is a famous topological index used in the field of mathematic, physic, chemistry, biology and telecommunications.
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    An Overview of Cell Zooming Algorithms and Power Saving Capabilities in Wireless Networks
    ( 2014) Tun, Khin Cho ; Kunagorn Kunavut
    Cell zooming has emerged as a potential strategy to develop a green communication system in our society and it has become an essential research area of wireless communication. Aiming to highlight the trend of existing cell zooming algorithms and their power saving capabilities, this paper reviews a number of cell zooming algorithms that have been proposed in the literature. Static cell zooming algorithms are effective for off-peak hours and their maximum power saving capability is 50% since off-peak duration is typically not more than 12 hours.Meanwhile dynamic cell zooming algorithms are applicable in full-day operation and they are useful not only for power saving but also for load balancing. However, on/off switching delay, signalling overhead due to traffic information exchange and how to attain information of traffic spatial distribution are existing challenges in dynamic cell zooming algorithms. One noticeable point is that relative power saving in dynamic cell zooming algorithm is less than 50% if traffic spatial distribution is considered. Since location management (LM) was designed for effectively servicing to customers, further researches could lead to work on location management (LM) based cell zooming algorithms for both effective servicing and energy saving.
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    An Overview of Digital Trunked Radio: Technologies and Standards
    ( 2014) Kunagorn Kunavut
    Land Mobile Radio (LMR) refers to the two-way radio communication system that allows users sharing the same range of frequency to communicate with the others. LMR can be roughly classified into two main systems which are conventional and trunked radio systems. In conventional system, a frequency band is permanently dedicated to a voice channel. However, using trunked radio system can increase the spectrum efficiency by having pool of frequencies which are temporarily assigned to a group of users called talk group only when required. In trunked radio system, analog trunked radio is going to be obsolete since digital trunked radio offers better functions and features in terms of voice quality, security, spectrum efficiency and cost. Hence, the commercial applications focus on the digital one. There are many digital trunked radio technologies lunched in the market. However, in this paper, only Terrestrial Trunked Radio (TETRA), Project 25 (P25) and Digital Mobile Radio (DMR) are discussed and compared since they are developed and standardized by international standards organizations. Moreover, these technologies are chosen by many users/operators and mostly deployed in many regions across the world.
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    Performance Analysis of Adaptive Location Update Schemes for Continuous Cell Zooming Algorithm in Wireless Network
    ( 2016) Tun, Khin Cho ; Kunagorn Kunavut
    To reduce the transmitted power of base stations in mobile wireless networks, continuous cell zooming algorithm is a feasible dynamic cell zooming algorithm. In this algorithm, location management is required in order to know the locations of users. Movement-based Update is not compatible and the application of Convention Periodic Update (CPU) scheme in continuous cell zooming algorithm can lead to a high signaling cost. Thus, aiming to highlight the effectiveness of newly proposed location update schemes, Time-Adaptive Periodic Update (TAPU) and Location-Adaptive Periodic Update (LAPU), a simulation-based performance analysis is conducted. Applying in continuous cell zooming algorithm, the performances of TAPU and LAPU are compared to that of Convention Periodic Update (CPU) scheme in terms of transmitted power ratio, outage ratio and the number of update messages. The performances of TAPU and LAPU are analyzed in a network with different number of users and in a network with different average moving speeds of users. The results show that compared to CPU, both TAPU and LAPU have no significant effect on power saving capability of continuous cell zooming algorithm in every scenario. Meanwhile, LAPU and TAPU give a significant reduction of update messages in every scenario. In terms of QoS effect, LAPU gives approximately the same outage ratio as CPU and a higher outage ratio occurs in TAPU.
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    Performance and Comparative Analysis of Energy Consumption for Mobile Ad Hoc Routing Protocols
    ( 2014) Kunagorn Kunavut
    Mobile ad hoc networks are energy-constrained networks, nodes in these networks are usually mobile and they are typically implemented in the specific areas where electrical power source is not available. Thus, the operations of these nodes must only rely on battery power or other exhaustible sources of energy. In addition, most of power in each node is required for communication with other nodes or gateway connected to the wired networks, this usually includes transmission of data and control overhead generated by ad hoc routing protocols to obtain the best paths to destination nodes/devices. Thus, to study the energy consumption of each routing protocol is one of the major concerns. In this work, number of simulation scenarios are constructed to study the energy consumption in each node using various routing protocols standardized by the Internet Engineering Task Force (IETF) MANET working Group which are OLSR (RFC 3626), DSR (RFC 4728) and AODV (RFC 3561).
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    Performance Evaluation of Dynamic Cell Zooming Algorithms in Omni-directional and Sector-based Cells
    ( 2014) Tun, Khin Cho ; Kunagorn Kunavut
    This paper evaluates and highlights the performance of three dynamic cell zooming algorithms applied in both omni-directional and sector-based networks. A possible framework compatible with dynamic cell zooming algorithms for user’s location detection is presented. The performance of each cell zooming algorithm is simulated in terms of power saving and possible outage in a full-day operation. According to simulated results, there is no significant difference between the performance of each algorithm and others at low traffic hours, but their performances are different at high traffic hours. From an overall comparison, the continuous cell zooming algorithm illustrates the best performance in terms of power saving, followed by fuzzy algorithm and then discrete algorithm. However, in terms of possible outage, the continuous algorithm is very sensitive to user movement and it shows a very high possible outage ratio. Meanwhile, the outage is totally removed in the discrete and fuzzy algorithms according to their concept. The dynamic cell zooming algorithms show a larger power saving in sector-based network since it hosts a more detailed plan to perform cell zooming.