24 research outputs found

    A Study of Application Layer Paradigm for Lower Layer Energy Saving Potentials in Cloud-Edge Social User Wireless Image Sharing

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    Energy saving becomes critical in modern cloud wireless multimedia and mobile communication systems. In this paper we propose to study a new paradigm named application layer Position-Value diversity for wireless image sharing for cloud-edge communications, which has significant energy saving potentials for modern wireless networking systems. In this new paradigm, saving energy is achieved by looking into application layer imaging traffic, in stead of MAC-PHY protocols at lower layers, and partitioning it into important positions and unimportant values. This paradigm could be integrated to existing wavelet-based tree compression, and truncation of image bit streams could be performed with regards to wireless communication energy budget estimation. Simulation results demonstrated that there are significant potentials of communication energy efficiency gain and Quality of Experience (QoE) enhancement in wireless image communication systems

    Special Issue on Performance Issues in Mobile Computing

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    Control and Performance In Packet, Circuit, and ATM Networks

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    xii,339 hlm, Ilust :23 c

    A New Collision Resolution Mechanism to Enhance the Performance of IEEE 802.11 DCF

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    The medium-access control (MAC) protocol is one of the key components in wireless local area networks (WLANs). The main features of a MAC protocol are high throughput, good fairness, energy efficiency, and support priority guarantees, especially under distributed contention-based environment. Based on the current standardized IEEE 802.11 distributed coordination function (DCF) protocol, this paper proposes a new efficient collision resolution mechanism, called GDCR Our main motivation is based on the observation that 802.11 DCF decreases the contention window to the initial value after each success transmission, which essentially assumes that each successful transmission is an indication that the system is under low traffic loading. GDCF takes a more conservative measure by halving the contention window size after c consecutive successful transmissions. This "gentle" decrease can reduce the collision probability, especially when the number of competing nodes is large. We compute the optimal value for c and the numerical results from both analysis and simulation demonstrate that GDCF significantly improve the performance of 802.11 DCF, including throughput, fairness, and energy efficiency. In addition, GDCF is flexible for supporting priority access by selecting different values of c for different traffic types and is very easy to implement it, as it does not requires any changes in control message structure and access procedures in DCF

    Performance Analysis of RFID Generation-2 Protocol

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    This paper investigates the performance of EPC-gloabl Generation-2 (Gen-2) [1] Ultra High Frequency (UHF) Radio Frequency Identification (RFID) protocol. Gen-2 protocol has a critical parameter Q that plays an important role in resolving tag collisions. Gen-2 protocol proposes an adaptive slot-count algorithm to adjust Q dynamically based on the type of replies from tags. In this paper, we define two performance metrics for tag identification: Query Success Rate (QSR) and Tag Identification Speed (TIS). We establish a Discrete- Time Markov Chain (DTMC) model for the Gen-2 and accordingly obtain quantitative results of QSR and TIS. Extensive simulations validate our theoretical analysis and demonstrate that the number of tags has little impact on the performance. In other words, QSR and TIS do not nearly decrease even though the number of tags may be increasing. Our model for Gen-2 protocol is also useful to study the performance of other RFID protocols

    Future Internet Services and Applications

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    The Internet has been successfully deployed for several decades due to its high flexibility in running over different physical media and supporting different high-layer protocols and applications, including traditional file transfer, email, and client-server-based web applications, among others. The future Internet is expected to be more agile, scalable, secure, and reliable. Meanwhile, we have witnessed the unprecedented development and growth of new applications and services in recent years ranging from location-based services, social networking, cloud computing, and peer-to-peer (P2P)-based applications. Such rapidly emerging applications with different requirements and implications for the future Internet design pose a significant set of problems and challenges

    AoA based sensing and performance analysis in cognitive radio networks

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    An Effective Collision Resolution Mechanism for Wireless LAN

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    Based on the current standardized IEEE 802.11 distributed coordination function (DCF) protocol, this paper proposes a new efficient collision resolution mechanism, called GDCF. Our main motivation is based on the observation that 802.11 DCF decreases the contention window to the initial value after each success transmission, which essentially assumes that each successful transmission is an indication that the system is under low traffic loading. GDCF takes a more conservative measure by halving the contention window size after c consecutive successful transmissions. This "gentle" decrease lowers the collision probability, especially when the competing node number is large. We compute the optimal value for c, and the numerical results from both analysis and simulation demonstrate that GDCF significantly improve the performance of 802.11 DCF including throughput, fairness, and energy efficiency. In addition, GDCF is,flexible for supporting priority access by selecting different values of c for different traffic types; it is fully compatible with the original 802.11 DCF, and simple to implement, as it does not requires changes in control message structure and access procedures in DCF
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