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wireless-ad-hoc-networks
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Mobility Aware QoS Multimedia Streaming in Mobile Ad Hoc Networks
, M.Sc. Thesis Sharif University of Technology ; Movaghar Rahimabadi, Ali (Supervisor)
Abstract
Achieving the required Quality of service (QoS) is a challenging task in the emerging next generation networked multimedia applications. Providing QoS guarantees becomes even more challenging when you add the complexities of wireless and mobile networks. An important aspect of wireless networks is their dynamic behavior. Especially when we need to transmit multimedia data over wireless networks, this problem becomes more significant. Live video with large end to end delay is meaningless and very low quality video is not satisfying. In recent years, a number of Protocols for providing guarantee of service are presented in the literature. These techniques include data link layer QoS schemes,...
An Approach for Security Improvement in VANETs
, M.Sc. Thesis Sharif University of Technology ; Hemmatyar, Ali Mohammad Afshin (Supervisor)
Abstract
Vehicular ad hoc networks are types of mobile ad hoc networks in which each automobile acts as an intelligent node and can have links to other automobiles and with equipments that are beside the road. The main difference between vehicular ad hoc networks and mobile ad hoc networks are in terms of higher speed of their components, extent, span and scale. One of the main concerns about designing vehicular ad hoc networks is users' security and protection of their privacy policy. Althoug a lot of protocols have been suggested for improvement of securities in these networks up to now, many research challenges regarding users' security and their privacy have been left and need to be considered...
A novel technique to control the traffic of wireless ad-hoc network by fuzzy systems and prediction with neural network
, Article Proceedings - CIMSim 2011: 3rd International Conference on Computational Intelligence, Modelling and Simulation, 20 September 2011 through 22 September 2011, Langkawi ; 2011 , Pages 18-21 ; 9780769545622 (ISBN) ; Manzuri, M.T ; Sharif University of Technology
Abstract
Wireless Ad-hoc Networks have been proposed for variety of applications. In this paper our goal is to find crisis points in the roads, such as accident locations, and asphalt-destruction points, which may cause traffics along the roads. The applied method for traffic prediction is based on back propagation algorithm. In this paper the length of packets are assumed to be constant. Along the road the traffic is modeled by a Poisson Process. With this model we can produce packets. The number of packets which are sending from a typical node to the other nodes is controlled by a fuzzy system. By appropriate training of a neural network, we have shown that, having the traffic packets at time (t)...
A model for traffic prediction in wireless ad-hoc networks
, Article Communications in Computer and Information Science ; Volume 241 CCIS , 2011 , Pages 328-335 ; 18650929 (ISSN) ; 9783642273360 (ISBN) ; Manzuri, M. T ; Latifi, N ; Sharif University of Technology
Abstract
In recent years, Wireless Ad-hoc networks have been considered as one of the most important technologies. The application domains of Wireless Ad-hoc Networks gain more and more importance in many areas. One of them is controlling and management the packet traffic. In this paper our goal is controlling the performance of every sections of pipeline of the factory by checking network periodically. Along the factory the traffic is modeled with a Poisson process. We present, with obtaining traffic packets at time (t) for each node in Wireless Ad-hoc Network, we can completely train a Neural Network and successfully predict the traffic at time (t+1) for each node. By this way we can recognize the...
Network layer challenges of IEEE 802.11n wireless ad hoc networks
, Article Lecture Notes of the Institute for Computer Sciences, Social-Informatics and Telecommunications Engineering ; Volume 72 LNICST , 2012 , Pages 377-388 ; 18678211 (ISSN) ; 9783642291562 (ISBN) ; Yazdani, N ; EffatParvar, M ; Teymoori, P ; Movaghar, A ; Sharif University of Technology
2012
Abstract
Recent demands toward high-speed wireless networks are growing. IEEE 802.11n, as the latest standard toward achieving higher speeds, aims to enhance IEEE 802.11 for higher throughputs. There are few works which analyze performance of this protocol in single-hop networks in terms of MAC layer-based parameters. Most of these works suggest disabling the RTS/CTS handshake to reduce MAC layer overheads. However, the effects of this protocol on the upper layers, especially the network layer, are still unknown. This paper deals with investigating performance of the network layer over IEEE 802.11n. Through extensive simulations performed in NS-2 we show that although network throughput is improved...
Reliable and energy efficient single source broadcasting using network coding in wireless Ad-hoc networks
, Article 2007 IEEE International Conference on Telecommunications and Malaysia International Conference on Communications, ICT-MICC 2007, Penang, 14 May 2007 through 17 May 2007 ; February , 2007 , Pages 81-85 ; 1424410940 (ISBN); 9781424410941 (ISBN) ; Pakravan, M. R ; Sharif University of Technology
2007
Abstract
There are applications where important and critical data should be sent to all nodes in a wireless Ad-hoc network. Flooding and its variants are typically used to achieve this target. Network coding can also be used for broadcasting in such an environment. Energy consumption in the network, coverage and total delay are all important parameters that should be considered when an algorithm is evaluated. In this article, a reliable and energy efficient single source broadcasting algorithm is proposed based on network coding. This algorithm guarantees the delivery of desired messages to all network nodes, consumes less energy compared and reduces the total delay compared to other algorithms. This...
Preventing black hole attack in AODV through use of hash chain
, Article 2011 19th Iranian Conference on Electrical Engineering, ICEE 2011, 17 May 2011 through 19 May 2011 ; May , 2011 , Page(s): 1 ; 9789644634284 (ISBN) ; Taheri, H ; Vakilinia, S ; Sharif University of Technology
2011
Abstract
Wireless ad hoc networks are vulnerable against many types of attacks including black hole. In this paper we investigate the effect of this attack on ad hoc networks. Furthermore, we use hash chain to prevent this type of attack in a network that uses AODV as a routing protocol and results of applying this method has been investigated. Simulation results using OPNET simulator indicates that packet delivery ratio, in the presence of malicious nodes, reduces remarkably and proposed approach can prevent the effect of black hole attacks
A novel approach to incentive-based cooperation in wireless ad hoc networks
, Article 2011 18th International Conference on Telecommunications, ICT 2011 ; 2011 , Pages 78-83 ; 9781457700248 (ISBN) ; Khalaj, B. H ; Vakilinia, S ; IBM Cyprus; University of Cyprus; Cyprus Tourism Organisation ; Sharif University of Technology
Abstract
Cooperation is an integral part of wireless ad hoc networks. In this paper, we introduce a combination of pricing and reputation-based mechanisms targeted at generating higher incentive for cooperation among nodes. The reputation-based part of the mechanism guarantees proper cooperation among sources. In addition, the pricing-based mechanism is added to ensure cooperation of relay nodes. In contrast with earlier works, a more comprehensive definition of cooperation is presented which guarantees a better reward and punishment system. In our approach, a multi-player game is defined with continuous strategy set and payoffs which lead to a more practical model. Based on the proposed game...
A survey of key pre-distribution and overlay routing in unstructured wireless networks
, Article Scientia Iranica ; Volume 23, Issue 6 , 2016 , Pages 2831-2844 ; 10263098 (ISSN) ; Yousefi'zadeh, H ; Movaghar, A ; Sharif University of Technology
Sharif University of Technology
2016
Abstract
Unstructured wireless networks such as mobile ad hoc networks and wireless sensor networks have been rapidly growing in the past decade. Security is known as a challenging issue in such networks, in which there is no fixed infrastructure or central trusted authority. Further, node limitations in processing power, storage, and energy consumption add further complexity to addressing security in such networks. While cryptography has proven to be an effective solution capable of satisfying most network security requirements, it requires the use of efficient key pre-distribution algorithms compatible with the limitation of unstructured wireless networks. Typically, a key pre-distribution...
Have you asked your neighbors? A Hidden Market approach for device-to-device offloading
, Article 17th International Symposium on a World of Wireless, Mobile and Multimedia Networks, WoWMoM 2016, 21 June 2016 through 24 June 2016 ; 2016 ; 9781509021857 (ISBN) ; Ahmadi, M ; Kosta, S ; Hui, P ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2016
Abstract
During the last years, researchers have proposed solutions to help smartphones offload heavy tasks to remote entities in order to improve execution time and reduce energy consumption. Lately, inspired by the promising results of message forwarding in opportunistic networks, many researchers have proposed strategies for task offloading towards nearby mobile devices. None of these strategies, though, proposes any mechanism that considers selfish users and, most importantly, that motivates and defrays the participating devices who spend their resources. In this paper, we address these problems and propose the design of a framework that integrates an incentive scheme and a reputation mechanism....
Trusted secure routing for ad hoc networks
, Article MobiWac'07 - Proceedings of the 5th ACM International Workshop on Mobility Management and Wireless Access, Chania, Crete Island, 22 October 2007 through 22 October 2007 ; 2007 , Pages 176-179 ; 9781595938091 (ISBN) ; Akhoondi, M ; Kargar, M ; Movaghar, A ; Sharif University of Technology
2007
Abstract
Cooperation among nodes is vital in Mobil Ac Hoc Networks (MANETs) since in such networks nodes depend on each other for forwarding and routing packets. However, cooperation in such operations consumes nodes' recourses such as battery and bandwidth. Therefore it is necessary to design incentive mechanisms to enforce nodes to forward packets when the source and destination of the packet are other nodes. In this paper, we present a distributed fair solution to judge, punish and re-admit a selfish node, forcing nodes to cooperate with each other. Our scheme is different from previous ones in that it combines two characteristics that have been separately handled in previous works. The first...
A novel contention window control scheme for IEEE 802.11 WLANs
, Article IETE Technical Review (Institution of Electronics and Telecommunication Engineers, India) ; Volume 29, Issue 3 , 2012 , Pages 202-212 ; 02564602 (ISSN) ; Movaghar, A ; Jabbehdari, S ; Kanellopoulos, D ; Sharif University of Technology
2012
Abstract
In the IEEE 802.11 standard, network nodes experiencing collisions on the shared medium need a mechanism that can prevent collisions and improve the throughput. Furthermore, a backoff mechanism is used that uniformly selects a random period of time from the contention window (cw) that is dynamically controlled by the Binary Exponential Backoff (BEB) algorithm. Prior research has proved that the BEB scheme suffers from a fairness problem and low throughput, especially under high traffic load. In this paper, we present a new backoff control mechanism that is used with the IEEE 802.11 distributed coordination function (DCF). In particular, we propose a dynamic, deterministic contention window...
Modeling of Interference Control in Wireless Ad-Hoc Networks in the Base of Transmission Rate Control in TCP
, M.Sc. Thesis Sharif University of Technology ; Haeri, Mohammad (Supervisor)
Abstract
An Ad-Hoc wireless network consists of a collection of geographically distributed nodes that communicate with each other over a wireless medium. These networks don’t use any infrastructure or base station to channel allocation. The important difference between wireless networks and wired networks is the broadcast nature of wireless communications. In these networks, each node transmits data to all of the nodes in the transmission range which may cause an increase in interference and data loss. On the other hand, due to mobility of users, fading the channel between them and change of routing, the probability of data loss increases. The extensive and successful employment of TCP variants in...
Security of Wireless Ad Hoc Networks
, M.Sc. Thesis Sharif University of Technology ; Movaghar, Ali (Supervisor)
Abstract
Nowadays wireless technology is widespread all over the world and there is a competition among companies to provide the most secure and high range wireless networks for their customers. This thesis focuses on the security of wireless ad hoc networks. There are lots of different encryption algorithms for securing wireless ad hoc networks. Some of the most important are: WEP, TKIP, WPA, WPA2. All other encryption methods of wireless ad hoc networks are derived from these methods. This thesis focuses on WEP and WPA2. For both algorithms, a literature review is conducted, a new approach to cracking is suggested, and tested on real data, and the future works are mentioned. For WEP, which is an...
Analysis of quantization effects on performance of hierarchical cooperation schemes in ad-hoc wireless networks
, Article Proceedings - Conference on Local Computer Networks, LCN ; 2011 , Pages 171-174 ; 9781612849287 (ISBN) ; Khalaj, B. H ; Sharif University of Technology
Abstract
In this paper, we analyze the role of the number of quantization bits on the third phase of the hierarchical cooperation scheme proposed by Ozgur et al. in 2007. The hierarchical cooperation scheme has a digital architecture and requires quantization of MIMO (Multiple-Input Multiple-Output) observations in the third phase. The choice of the number of quantization bits Q has direct effect on the pre-constant factor of the network throughput. By increasing the number of quantization bits, the MIMO capacity in the second phase increases at the expense of higher computational complexity of the third phase. We investigate such trade-off and show that there is an optimum number of quantization...
Game-theoretic approach to mitigate packet dropping in wireless Ad-hoc networks
, Article 2011 IEEE Consumer Communications and Networking Conference, CCNC'2011, 8 January 2011 through 11 January 2011, Las Vegas, NV ; 2011 , Pages 163-165 ; 9781424487905 (ISBN) ; Farhat, F ; Pakravan, M. R ; Aref, M. R ; Sharif University of Technology
2011
Abstract
Performance of routing is severely degraded when misbehaving nodes drop packets instead of properly forwarding them. In this paper, we propose a Game-Theoretic Adaptive Multipath Routing (GTAMR) protocol to detect and punish selfish or malicious nodes which try to drop information packets in routing phase and defend against collaborative attacks in which nodes try to disrupt communication or save their power. Our proposed algorithm outranks previous schemes because it is resilient against attacks in which more than one node coordinate their misbehavior and can be used in networks which wireless nodes use directional antennas. We then propose a game theoretic strategy, ERTFT, for nodes to...
Throughput of Large One-Hop Ad Hoc Wireless Networks With General Fading
, Article IEEE Transactions on Vehicular Technology ; Volume 64, Issue 7 , 2015 , Pages 3304-3310 ; 00189545 (ISSN) ; Khalaj, B. H ; Alishahi, K ; Shah Mansouri, H ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2015
Abstract
We consider the problem of determining throughput of one-hop unicast transmissions in ad hoc wireless networks. We consider an interference-limited scenario in which wireless links between different nodes are modeled by independently and identically distributed random variables. The main decoding challenge for receive nodes is due to interference of nonintended concurrent transmissions. In this scenario, we consider a heuristic one-hop transmission strategy based on activating source-destination pairs with strongest direct links and forcing other pairs to be silent. We present a closed-form expression for throughput scaling of such strategy, for a completely general channel power...
Is really NACK protocol secure to be employed in MANETs?
, Article Proceedings - 17th IEEE International Conference on Computational Science and Engineering, CSE 2014, Jointly with 13th IEEE International Conference on Ubiquitous Computing and Communications, IUCC 2014, 13th International Symposium on Pervasive Systems, Algorithms, and Networks, I-SPAN 2014 and 8th International Conference on Frontier of Computer Science and Technology, FCST 2014, 19 December 2014 through 21 December 2014 ; 2015 , Pages 1644-1647 ; 9781479979813 (ISBN) ; Mackvandi, A ; Taghavi, M ; Zare Bidoki, M ; Ghasemi, M ; Neshati, A ; Liu, X ; El Baz, D ; Kang, K ; Hsu, C. H ; Chen, W ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2015
Abstract
MANET, which stands for Mobile Ad-hoc Network, is composed of a group of self-organized and wireless nodes that do not possess any predictable and fixed infrastructure. When nodes want to communicate with each other, they have to pass on their messages directly or indirectly. In case the destination node is out of the transmission range, the source node has to rely on intermediate nodes, which, in this case, is called indirect transmission. On the other hand, if the destination node is the neighboring node, there is no need to employ intermediate nodes, which, in this case, is called direct transmission. Over the past years, security issues in MANETs have received a great deal of attention...
Counter-based broadcasting: Modeling and performance analysis in CSMA-based wireless networks
, Article IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC, 13 September 2009 through 16 September 2009, Tokyo ; 2009 ; 9781424451234 (ISBN) ; Khalaj, B. H ; Pakravan, M. R ; Khodaian, A. M ; Sharif University of Technology
IEEE
2009
Abstract
Counter-based broadcasting improves the performance of flooding by preventing the network from being swamped by a large number of rebroadcast messages. In such approach, the rebroadcast decision is made based on counting duplicated packets in order to restrict the number of extra retransmissions. In this article, using a rigorous theoretic analysis, an upper bound on the performance of counter-based broadcasting for saturated networks is derived. Our model assumes a CSMA-based static multi-hop ad-hoc network. The derived analytical model can be used to predict the behavior of counter-based broadcasting schemes. It especially provides the required insight on the impact of different network...
Hybrid approach to analyze the impact of vehicular traffic on performance of 802.11p protocol for safety communications in vehicular ad hoc networks: a quantitative analysis
, Article Wireless Personal Communications ; Volume 97, Issue 3 , 2017 , Pages 4493-4528 ; 09296212 (ISSN) ; Afshin Hemmatyar, A. M ; Sharif University of Technology
Abstract
The rapid developments in wireless communications have introduced the vehicular ad hoc networks as an efficient tool to improve the safety of traffic through Dedicated Short Range Communications systems on highways. This paper addresses the broadcast mode of the 802.11p protocol and it quantitatively analyzes the impact of the highway vehicular traffic on its performance in terms of the packet delivery ratio and the packet transmission delay. To this aim, we propose to consider the number of the contending vehicles as a traffic-dependent stochastic counting process, which can be computed by analyzing the inter-vehicle spacing distribution in different traffic conditions. Based on the...