Current Issue : January - March Volume : 2017 Issue Number : 1 Articles : 5 Articles
The origin of Mobile ad hoc network (MANET) was started in 1970 as packet radio\nnetwork (PRNET), later on different researches were made on it in different ages.\nMANET works under no fixed infrastructure in which every node works likes a router\nthat stores and forwards packet to final destination. Due to its dynamic topology,\nMANET can be created anywhere, anytime. As there are limited resources in MANET\nso it faces many problems such as security, limited bandwidth, range and power constraints.\nDue to this, many new routing protocols are proposed. This article examines\ndifferent techniques to manage congestion control, security issues, different layers\nattacks, routing protocols and challenges that are faced by MANET....
Random access protocols are a key feature of a family of emerging communication networks such as\nmachine-to-machine, radio frequency identification (RFID), and sensor networks. To accommodate the needs of such\nnetworks with a massive number of uncoordinated devices, new random multiple access (MAC) protocols have been\nproposed that aim to improve the system efficiency by resolving collisions in the received signal. In this work, we\nconsider one of such protocols, called frameless ALOHA, and propose two techniques to improve its energy efficiency\nwithout sacrificing the network throughput. More specifically, we propose mechanisms to adaptively control the\naccess probability at the users. The proposed mechanisms are local and like the original frameless ALOHA, no\ncoordination between the users is needed. Our simulation results verify the improvement achieved in the energy\nefficiency by the proposed techniques...
Traditionally, allocating of Ethernet Passive Optical Network (EPON) bandwidth schemes relied on\na centralized architecture where their Optical Line Terminal (OLT) is the sole intelligent device\nwith the capability for the arbitration of bandwidth based on time-division access for the upstream\nshared channel. However, any breakdown in the OLT bandwidth allocation will affect the\nallotment for Optical Network Units (ONUs). Few researches had dealt with a decentralized approach\nfor the EPON and most of the solutions proposed involved additional cost by adding new\ncomplex devices to the original architecture. This paper proposes an intelligent decentralized\nmechanism in EPON that enhances the network performance using intelligent agents specification\nbased on the IEEE 802.3 ah standards in the foundation for intelligent physical agent which is\ncompatible with an Internet Protocol (IP)-based network. Specifically, this paper proposes a novel\ndistributed scheme that supports differentiated services and ensures QoS for both Inter-and IntraONU\nallocation. The proposed mechanism introduces a unique direct communication between the\nONUs supported by identical dynamic bandwidth allocation algorithms running simultaneously in\neach ONU. In addition to being fully distributed, the proposed scheme is asynchronous, scalable,\nand dynamic with flexibility and reliability in handling data, voice and video....
Multi-hop network has received growing attention recently with the widely use of wireless network communication\ntechnology. At the same time, the security of multi-hop network is facing more serve challenges. Unfortunately,\nclassic techniques for computer virus spreading model cannot be applied to multi-hop network because of\nignoring dynamic topology of network. In this paper, classic susceptible-infected (SI) model, susceptible-infectedsusceptible\n(SIS) model and susceptible-infected-removed (SIR) model are applied to multi-hop network based on\nrandom way-point (RWP) model, and contact duration of virus is introduced. Virus spreading behaviors are\nexamined through contact duration of virus, communication radius of node, distribution density of node, and the\nnumber of initial infected nodes. Simulation results show that node mobility has significant effect on virus\nspreading behaviors. In particular, a special node speed that can lead network to appear the fastest-spreading virus\nphenomenon is found. The special speed is approximately equal to the ratio of communication radius of node to\ncontact duration of virus. Distribution density of node and the number of initial infected nodes almost do not affect\nthe special speed....
Wireless Mesh Network is a promising technology with many challenges yet to be addressed. Novel\nand efficient algorithms need to be developed for routing and admission control with the objective\nto increase the acceptance ratio of new calls without affecting the Quality of Service (QoS) of\nthe existing calls and to maintain the QoS level provided for the mobile calls. In this paper, a novel\nMarkov Decision-based Admission Control and Routing (MDACR) algorithm is proposed. The MDACR\nalgorithm finds a near optimal solution using the value iteration method. To increase the admission\nrate for both types of calls, a multi-homing admission and routing algorithm for handoff and\nnew calls is proposed. This algorithm associates the user with two different access points which is\nbeneficial in a highly congested network and proposes a new routing metric to assure seamless\nhandoff in the network. Our proposed algorithm outperforms other algorithms in the literature in\nterms of handoff delay, blocking probability, and number of hard handoff....
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