Current Issue : July - September Volume : 2019 Issue Number : 3 Articles : 5 Articles
The application carrier of wireless body area network (WBAN) is human; due to changes in peopleâ??s sports status or physical\nhealth and other reasons, the business traffic fluctuates greatly, which requires the network to have good adaptability. In addition,\nthe energy consumption problem is also a key factor restricting the applications of the WBAN. At present, the proposed MAC\nprotocol is not highly adaptive and has low energy efficiency. To solve this problem, this paper proposes an adaptiveMACprotocol\nbased on IEEE802.15.6 for WBAN (A-MAC).The protocol sets the data to three priorities according to the type of service; the\nsuperframe structure of IEEE802.15.6 is improved and reorganized into four phases: the beacon phase, the contention access\nphase, the noncontention access phase, and the inactive phase. The length of the contention access phase and the noncontention\naccess phase is adjusted according to the proportion of nodes that generate each priority data. The contention access phase is\nfurther divided into three subphases, and the length of the subphase is dynamically adjusted according to the data priority. In\nthe contention access phase, all nodes compete for access channel according to the channel access policy. The random data that\ncompetes successfully transmits data directly, and the periodic data that competes successfully transmits data in the allocated time\nslots of the noncontention access phase. Finally through the simulation of the proposed A-MAC protocol and IEEE 802.15.6 MAC\nprotocol andCA-MAC protocol in network performancewhichwere compared, the results show that in terms of throughput, power\nconsumption, and the network time delay, the network performance using A-mac protocol is better than the network performance\nusing IEEE802.15.6 MAC and CA-MACprotocols....
Accurate real-time traffic prediction is required in many networking applications like dynamic resource allocation and power\nmanagement. This paper explores a number of predictors and searches for a predictor which has high accuracy and low\ncomputation complexity and power consumption. Many predictors from three different classes, including classic time series,\nartificial neural networks, and wavelet transform-based predictors, are compared. These predictors are evaluated using real\nnetwork traces. Comparison of accuracy and cost, both in terms of computation complexity and power consumption, is presented.\nIt is observed that a double exponential smoothing predictor provides a reasonable tradeoff between performance and\ncost overhead....
Simultaneous wireless information and power transfer is a practicable solution to encourage\nenergy-constrained relay nodes to cooperate with the source to transmit information to the destination.\nIn this paper, we study the outage performance of hybrid protocol based amplify-and-forward (AF)\nrelay networks over asymmetric fading channels, where the source-relay link and the relay-destination\nlink are subjected to Rician fading and Rayleigh fading, respectively. In particular, we derive the lower\nbound of outage probability and the upper bound of outage capacity based on a high signal-to-noise\nratio approximation, respectively. We further investigate the effects of various system parameters,\nsuch as the parameters of hybrid protocol, the target rate, and the Rician K-factor, on the investigated\nnetwork. It is shown that a good selection of parameters of hybrid protocol is of significance to\nimprove system capacity, and that a larger Rician factor is desirable in the investigated network....
Emerging applications such as industrial automation, in-vehicle, professional audiovideo,\nand wide area electrical utility networks require strict bounds on the end-to-end network\ndelay. Solutions so far to such a requirement are either impractical or ineffective. Flow based\nschedulers suggested in a traditional integrated services (IntServ) framework are O(N) or O(log N),\nwhere N is the number of flows in the scheduler, which can grow to tens of thousands in a core\nrouter. Due to such complexity, class-based schedulers are adopted in real deployments. The classbased\nsystems, however, cannot provide bounded delays in networks with cycle, since the\nmaximum burst grows infinitely along the cycled path. Attaching a regulator in front of a scheduler\nto limit the maximum burst is considered as a viable solution. International standards, such as IEEE\n802.1 time sensitive network (TSN) and IETF deterministic network (DetNet) are adopting this\napproach as a standard. The regulator in TSN and DetNet, however, requires flow state information,\ntherefore contradicts to the simple class-based schedulers. This paper suggests non-work\nconserving fair schedulers, called â??regulating schedulersâ?? (RSC), which function as a regulator and\na scheduler at the same time. A deficit round-robin (DRR) based RSC, called nw-DRR, is devised\nand proved to be both a fair scheduler and a regulator. Despite the lower complexity, the input portbased\nnw-DRR is shown to perform better than the current TSN approach, and to bind the end-toend\ndelay within a few milliseconds in realistic network scenarios....
In this contribution, the authors perform a detailed analysis relating to the use of the\nmulticonductor UIC (Union Internationale des Chemins de fer) cables as a broadband data\ntransmission channel onboard regional trains. The analysis is performed evaluating the channel\nfrequency response and the channel capacity as a function of the distance between communication\ndevices, in the 2â??30 MHz frequency range of broadband powerline communications . The per unit\nlength (p.u.l.) parameters are measured and simulated in a finite element method (FEM) code,\nallowing accurate full multiconductor simulations to evaluate the attenuations of the selected\nchannel for communication and the cross-talk between cables. This study has been conducted\nconsidering that there are other signals carried by the cable, during regular train operation, and\ntheir integrity needs to be taken into account. The results show that, as a matter of fact, UIC cables\ncan be used to transmit high-speed data; this can be exploited for introducing additional facilities\n(i.e., infotainment, safety features and so on) onboard regional trains, at a reasonably low cost, since\nno new cabling harnesses need be installed....
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