Current Issue : April - June Volume : 2016 Issue Number : 2 Articles : 5 Articles
Target tracking applications in wireless sensor networks need to achieve energy efficiency, tracking accuracy, and\ncertain real-time constraints in response to fast-moving targets. From a layer view, an energy-efficient cross-layer\ncommunication protocol that consists of a medium access control layer and network routing layer is necessary for\njoint optimization. Due to the interference and contention over the wireless medium, the limited resources of\nbattery-operated sensor nodes, and the dynamic topology of large-scale networks, this cross-layer design becomes a\nchallenging task. In this research, we exploit a cluster routing algorithm over large-scale networks and propose a\nlow-duty-cycle medium access control (MAC) algorithm to reduce collision, idle-listening, and overhearing. In\naddition, our work focuses on the joint optimization of routing and a MAC strategy for achieving a good trade-off\nbetween low delay, energy efficiency, and tracking accuracy. To deploy this protocol in a real tracking application, we\nalso propose a clustering synchronization procedure that does not require distributing the global timing information\nover the complete network to achieve network-wide time synchronization. An analytical model and extensive\nsimulations are proposed to evaluate and compare the performance of our work with existing protocols. Simulation\nand analysis results show that our approach achieves better communication delay and thus better tracking error while\nmaintaining reasonable energy consumption compared to other cases....
With the development and widespread application of wireless sensor networks (WSNs), the amount of sensory data\ngrows sharply and the volumes of some sensory data sets are larger than terabytes, petabytes, or exabytes, which\nhave already exceeded the processing abilities of current WSNs. However, such big sensory data are not necessary for\nmost applications of WSNs, and only a small subset containing critical data points may be enough for analysis, where\nthe critical data points including the extremum and inflection data points of the monitored physical world during\ngiven period. Therefore, it is an efficient way to reduce the amount of the big sensory data set by only retrieving the\ncritical data points during sensory data acquisition process. Since most of the traditional sensory data acquisition\nalgorithms were only designed for discrete data and did not support to retrieve critical points from a continuously\nvarying physical world, this paper will study such a problem. In order to solve it, we firstly provided the formal\ndefinition of the �´-approximate critical points. Then, a data acquisition algorithm based on numerical analysis and\nLagrange interpolation is proposed to acquire the critical points. The extensive theoretical analysis and simulation\nresults are provided, which show that the proposed algorithm can achieve high accuracy for retrieving the\n�´-approximate critical points from the monitored physical world....
The capability of quality-of-service (QoS) provisioning is of particular importance for multi-hop wireless networks\nwhen the real-time applications boost in current days. The scheduling and delivery of data packets in a deficient\nmethod may probably cause network congestion, which will in turn decrease the capability of QoS provisioning in the\nnetwork. To this end, we propose a joint QoS provisioning and congestion control scheme for multi-hop wireless\nnetwork in this paper based on our previous works of Differentiated Queueing Service (DQS) and Semi-TCP, which\nprovide per-packet granular QoS and carry out efficient hop-by-hop congestion control, respectively. While DQS and\nSemi-TCP are studied separately, we investigate the arising issues in the joint scheme and propose possible solutions\naccordingly, including a fast estimation of the latest departure time, a method to handle overdue packets, and an\nadaptive ACK scheme, as well as the design of a shared database cross-layer architecture for the implementation in\nthe protocol stack. Simulation results show that our proposal improves the network performance in terms of goodput,\ndelivery ratio, and end-to-end delay significantly, particularly in the scenario of mobile users. Our discussion and\nsimulation results both indicate that the proposed joint scheme is flexible and adaptive to the dynamic multi-hop\nwireless network environment....
Impact of medium access control (MAC) on throughput of IEEE 802.11-based multi-hop wireless networks is not\ncompletely understood despite numerous research efforts. Researchers have explored the MAC interaction of two-flow\ntopologies in order to better understand the MAC behavior of nodes in generic multi-hop wireless network. Prior\nresearch has considered two flow interactions under the assumption of same transmission and carrier sensing range.\nThis research extends and completes the existing body of work by relaxing the assumption of same transmission and\ncarrier sensing range to realize more practical and realistic two-flow topologies. Twenty-five unique possible two-flow\ntopologies can exist in general multi-hop wireless networks. The topologies have been classified into six categories\nbased on MAC layer behavior and per flow throughput. Closed-form expressions for occurrence probabilities of the\nidentified categories have been derived with particular observation that carrier sensing range-based categories have\nhigh occurrence probability and cannot be ignored. MAC behavior of each category is discussed. It is observed that\ndifferent transmission and carrier sensing ranges significantly affect the MAC behavior and the throughput of flows.\nBased on the behavior, exact throughput of the two single hop flows is analytically computed. The results achieved\nthrough analysis have been compared with the simulated results to verify the accuracy of analysis. This research will\nserve as basis for MAC behavior analysis of generic multi-hop wireless networks....
In this paper, we analyze the performance of interference alignment of device-to-device (D2D) uplink underlay\ncellular networks. By fully considering the impact of imperfect precoding vectors caused by limited feedback, the\nexact closed-form expressions of average throughput for cellular network and D2D network are derived in terms of\ntransmit power and the number of feedback bits. The accuracy of the average throughput is verified by simulation\nresults. Our analytic results provide great promises to practical system designs...
Loading....