Current Issue : July - September Volume : 2014 Issue Number : 3 Articles : 5 Articles
Vehicular ad hoc networks (VANETs) are going to be an important communication infrastructure in our moving life.\nThe design of routing protocols in VANETs is a significant and necessary issue for supporting VANET-based applications.\nHowever, due to high mobility, frequent link disconnection, and uneven distribution of vehicles, it becomes quite\nchallenging to establish a robust route for delivering packets. This paper presents a connectivity-aware intersectionbased\nrouting (CAIR) protocol to address these problems by selecting an optimal route with higher probability of\nconnectivity and lower experienced delay; then, geographical forwarding based on position prediction is used to\ntransfer packets between any two intersections along the route. Simulation results show that the proposed protocol\noutperforms existing routing protocols in terms of data delivery ratio and average transmission delay in typical urban\nscenarios....
With growing interest in using cognitive radio (CR) technology in wireless communication systems for vehicles, it is\nenvisioned that future vehicles will be CR-enabled. This paper discusses CR technologies for vehicular networks aimed\nat improving vehicular communication efficiency. CR for vehicular networks has the potential of becoming a killer CR\napplication in the future due to a huge consumer market for vehicular communications. This paper surveys novel\napproaches and discusses research challenges related to the use of cognitive radio technology in vehicular ad hoc\nnetworks. We review how CR technologies such as dynamic spectrum access, adaptive software-defined radios, and\ncooperative communications will enhance vehicular communications and, hence, present the potential of\ntransforming vehicle communication in terms of efficiency and safety. Our work is different from existing works in that\nwe provide recent advances and open research directions on applying cognitive radio in vehicular ad hoc networks\n(CR-VANETs) focusing on architecture, machine learning, cooperation, reprogrammability, and spectrummanagement\nas well as QoE optimization for infotainment applications. A taxonomy of recent advances in cognitive radio for\nvehicular networks is also provided. In addition, several challenges and requirements have been identified. The\nresearch on applying CR in vehicular networks is still in its early stage, and there are not many experimental platforms\ndue to their complex setup and requirements. Some related testbeds and research projects are provided at the end....
Monitoring the illegal movement across national border effectively is a challenging problem. The emerging\ntechnology of wireless sensor network (WSN) is expected to provide a new way to realize energy-efficient border\nintrusion detection. We propose a scheme to measure and guarantee the coverage quality of WSN. We also design a\nnew coverage model for detecting one-direction path. The simulation results shows that the new coverage model\ncould not only detect the intrusion in border area well, but also extend the network lifetime in an efficient way....
The use of field programmable gate array (FPGA) can improve the processing performance of many systems,\r\nincluding wireless sensor networks (WSNs). Moreover, FPGA devices permit remote and runtime hardware reconfiguration,\r\nwhich implies benefits in WSNs deployment and maintainability and finally, cost reduction. Thus larger circuits can be realized\r\nusing this module. Along with the logical implementation the wireless sensor node has also been designed and implemented to\r\nexhibit the functionality of the node�s transmitter, receiver and main controller before the actual deployment. Therefore, the\r\nnode will support only those hardware components required by the target application and that will reduce the node power\r\nconsumption. In this work the main task of FPGA based emulator is to optimize power requirement and analyze performance of\r\nreal time applications in WSNs....
In this paper, the multinode amplify-and-forward cooperative communications for a network of N nodes is studied via\nthe novel concept of many-to-many space-time network coding (M2M-STNC). Communication under the M2M-STNC\nscheme is performed over two phases: (1) the broadcasting phase and (2) the cooperation phase. In the former phase,\neach node broadcasts its data symbol to all the other nodes in the network in its allocated time slot, while in the latter\nphase, simultaneous transmissions from N - 1 nodes to a destination node take place in their time slot. In addition,\nthe M2M-STNC scheme with optimal node selection (i.e., M2M-STNC-ONS) is proposed. In this scheme, the optimal\nrelay node is selected based on the maximum harmonic mean value of the source, intermediate, and destination\nnodes� scaled instantaneous channel gains. Theoretical symbol-error-rate analysis for M-ary phase shift keying (M-PSK)\nmodulation is derived for both the M2M-STNC and M2M-STNC-ONS schemes. Also, the effect of timing synchronization\nerrors and imperfect channel state information on the SER performance and achievable rates is analytically studied. It\nis shown that the proposed M2M-STNC-ONS scheme outperforms the M2M-STNC scheme and is less sensitive to\ntiming offsets and channel estimation errors. It is envisioned that the M2M-STNC-ONS scheme will serve as a potential\nmany-to-many cooperative communication scheme with applications spanning sensor and mobile ad hoc networks....
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