Download or read book MAC Layer and Routing Protocols for Wireless Ad Hoc Networks with Asymmetric Links and Performance Evaluation Studies written by Guoqiang Wang and published by . This book was released on 2007 with total page 201 pages. Available in PDF, EPUB and Kindle. Book excerpt: In a heterogeneous mobile ad hoc network (MANET), assorted devices with different computation and communication capabilities co-exist. In this thesis, we consider the case when the nodes of a MANET have various degrees of mobility and range, and the communication links are asymmetric. Many routing protocols for ad hoc networks routinely assume that all communication links are symmetric, if node A can hear node B and node B can also hear node A. Most current MAC layer protocols are unable to exploit the asymmetric links present in a network, thus leading to an inefficient overall bandwidth utilization, or, in the worst case, to lack of connectivity. To exploit the asymmetric links, the protocols must deal with the asymmetry of the path from a source node to a destination node which affects either the delivery of the original packets, or the paths taken by acknowledgments, or both. Furthermore, the problem of hidden nodes requires a more careful analysis in the case of asymmetric links. MAC layer and routing protocols for ad hoc networks with asymmetric links require a rigorous performance analysis. Analytical models are usually unable to provide even approximate solutions to questions such as end-to-end delay, packet loss ratio, throughput, etc.

Download or read book Cross Layer Optimization for Protocols in Mobile Adhoc Networks written by Anita Yadav and published by GRIN Verlag. This book was released on 2020-03-17 with total page 142 pages. Available in PDF, EPUB and Kindle. Book excerpt: Doctoral Thesis / Dissertation from the year 2016 in the subject Computer Science - Miscellaneous, grade: 16, , language: English, abstract: In this thesis, we have modified AODV routing protocol by incorporating link prediction algorithm using a proposed link prediction model. This algorithm predicts the link availability time and even before the link breaks; either it repairs the route locally or sends information to the source nodes to enable them to initiate a new route search well in time. This algorithm improves the quality of service of the network. Simulation results show that AODV routing algorithm with link availability model performs better than the existing AODV. Advances in wireless technology and hand-held computing devices have brought revolution in the area of mobile communication. The increasing mobility of humans across the globe generated demand for infrastructure-less and quickly deployable mobile networks. Such networks are referred to as Mobile Adhoc Networks (MANET). Usually, nodes in a MANET also act as a router while being is free to roam while communicating each others. Adhoc networks are suited for use in situations where infrastructure is unavailable or to deploy one is not cost-effective. Frequent changes in network topology due to mobility and limited battery power of the mobile devices are the key challenges in the adhoc networks. The depletion of power source may cause early unavailability of nodes and thus links in the network. The mobility of nodes will also causes frequent routes breaks and adversely affects the required performance for the applications. Availability of a route in future mainly depends on the availability of links between the nodes forming the route. Therefore, it is important to predict the future availability of a link that is currently available. We have proposed an analytical model for link prediction using Newton divided difference method. This link availability algorithm is incorporated in AODV routing algorithm (AODVLP) to evaluate the performance of AODV routing protocol using the metrics viz. delivery rate, average end-to-end delay, average RTS collisions per node and route failure. In the existing AODV protocol, packets are routed until a link in the existing path fails. This results in degradation of quality of service of network in terms of end-to-end delay and delivery ratio.

Download or read book Proceedings of the ACM International Workshop on Performance Evaluation of Wireless Ad Hoc Sensor and Ubiquitous Networks written by and published by . This book was released on 2004 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Performance Enhancements for Ad Hoc Networks Using Mobility location Information written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Performance of a mobile ad hoc network (MANET) depends directly on the quality of routes selected by the routing protocol at the network layer and the packet transmission efficiency of the MAC layer protocol. The network layer routing protocol used in a MANET does not truly reflect the exact network topology as there is always a delay between topology changes in the network due to user's mobility and its corresponding routing table changes at the network layer by the routing protocol. Therefore, high user mobility in MANETs causes frequent link breaks when a pair of mobile user nodes, which have moved out of the transmission range of each other but are still shown as neighbors by the routing table, try to communicate with each other. This causes several unnecessary retransmissions between them at the MAC layer before the link is declared dead. Such retransmissions result in inefficient network resource utilization as power and bandwidth are wasted in transmission attempts by the sender node to send packet to the out-of-range receiver node. This research work proposes enhancements for the MAC layer protocol with associated changes at the network layer routing protocol that reduce link break probability, collision probability faced by a transmission, and solve the channel under-utilization problem because of the exposed terminal problem. The proposed schemes, i.e., location prediction check, transmission awareness and service differentiation, use current ongoing transmission information contained in the MAC layer protocol's handshake packets with piggybacked transmitting node's mobility-location information. A higher overall performance is achieved with the proposed implementation of the routing protocol over the MAC layer protocol in terms of throughput, power utilization and better quality of service (QoS).

Download or read book Position based Routing and MAC Protocols for Wireless Ad hoc Networks written by Hadi Noureddine and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents the Forecasting Routing Technique (FORTEL), a routing protocol for Mobile Ad-Hoc Networks (MANETs) based on the nodes' Location Information. FORTEL stores the nodes' location information in the Location Table (LT) in order to construct routes between the source and the destination nodes. FORTEL follows the source routing strategy, which has rarely been applied in position-based routing. According to the source routing strategy, the end-to-end route is attached to the packet, therefore, the processing cost, in regards to the intermediate nodes that simply relay the packet according to route, is minimized. FORTEL's key mechanisms include: first, the location update scheme, employed to keep the LT entries up-to-date with the network topology. Besides the mobility variation and the constant rate location update schemes applied, a window location update scheme is presented to increase the LT's information accuracy. Second, the switching mechanism, between "Hello" message and location update employed, to reduce the protocol's routing overhead. Third and most important is the route computation mechanism, which is integrated with a topology forecasting technique to construct up-to-date routes between the communication peers, aiming to achieve high delivery rate and increase the protocol robustness against the nodes' movement. FORTEL demonstrates higher performance as compared to other MANET's routing protocols, and it delivers up to 20% more packets than AODV and up to 60 % more than DSR and OLSR, while maintaining low levels of routing overhead and network delay at the same time. The effectiveness of the window update scheme is also discussed, and it proves to increase FORTEL's delivery rate by up to 30% as compared to the other update schemes. A common and frequently occurring phenomenon, in wireless networks, is the Hidden Terminal problem that significantly impacts the communication performance and the efficiency of the routing and MAC protocols. Beaconless routing approach in MANETs, which delivers data packets without prior knowledge of any sort Hof information, suffers from packet duplication caused by the hidden nodes during the contention process. Moreover, the throughput of the IEEE MAC protocol decreases dramatically when the hidden terminal problem occurs. RTS/CTS mechanism fails to eliminate the problem and can further degrade the network's performance by introducing additional overhead. To tackle these challenges, this thesis presents two techniques, the Sender Suppression Algorithm and the Location-Aided MAC, where both rely on the nodes' position to eliminate packet duplication in the beaconless routing and improve the performance of the 802.11 MAC respectively. Both schemes are based on the concept of grouping the nodes into zones and assign different time delay to each one. According to the Sender Suppression Algorithm, the sender's forwarding area is divided into three zones, therefore, the local timer, set to define the time that the receiver has to wait before responding to the sender's transmission, is added to the assigned zone delay. Following the first response, the sender interferes and suppresses the receivers with active timer of. On the other hand, the Location-Aided MAC, essentially a hybrid MAC, combines the concepts of time division and carrier sensing. The radio range of the wireless receiver is partitioned into four zones with different zone delays assigned to each zone. Channel access within the zone is purely controlled by CSMA/CA protocol, while it is time-based amongst zones. The effectiveness of the proposed techniques is demonstrated through simulation tests. Location-Aided MAC considerably improves the network's throughput compared to CSMA/CA and RTS/CTS. However, remarkable results come when the proposed technique and the RTS/CTS are combined, which achieves up to 20% more throughput as compared to the standalone RTS/CTS. Finally, the thesis presents a novel link lifetime estimation method for greedy forwarding to compute the link duration between two nodes. Based on a newly introduced Stability-Aware Greedy (SAG) scheme, the proposed method incorporates the destination node in the computation process and thus has a significant advantage over the conventional method, which only considers the information of the nodes composing the link.

Download or read book Mobile Ad Hoc Networks written by G Ram Mohana Reddy and published by CRC Press. This book was released on 2016-08-19 with total page 139 pages. Available in PDF, EPUB and Kindle. Book excerpt: In recent years, a lot of work has been done in an effort to incorporate Swarm Intelligence (SI) techniques in building an adaptive routing protocol for Mobile Ad Hoc Networks (MANETs). Since centralized approach for routing in MANETs generally lacks in scalability and fault-tolerance, SI techniques provide a natural solution through a distributed approach for the adaptive routing for MANETs. In SI techniques, the captivating features of insects or mammals are correlated with the real world problems to find solutions. Recently, several applications of bio-inspired and nature-inspired algorithms in telecommunications and computer networks have achieved remarkable success. The main aims/objectives of this book, "Mobile Ad Hoc Networks: Bio-Inspired Quality of Service Aware Routing Protocols", are twofold; firstly it clearly distinguishes between principles of traditional routing protocols and SI based routing protocols, while explaining in detail the analogy between MANETs and SI principles. Secondly, it presents the readers with important Quality of Service (QoS) parameters and explains how SI based routing protocols achieves QoS demands of the applications. This book also gives quantitative and qualitative analysis of some of the SI based routing protocols for MANETs.

Download or read book Secure Routing and Medium Access Protocols in Wireless Multi hop Networks written by Soufiene Djahel and published by GRIN Verlag. This book was released on 2011-10-28 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt: Doctoral Thesis / Dissertation from the year 2011 in the subject Computer Science - Internet, New Technologies, Lille 1 University (Laboratoire d'Informatique Fondamentale de Lille), course: Security in Wireless Multi-hop Networks, language: English, abstract: While the rapid proliferation of mobile devices along with the tremendous growth of various applications using wireless multi-hop networks have significantly facilitate our human life, securing and ensuring high quality services of these networks are still a primary concern. In particular, anomalous protocol operation in wireless multi-hop networks has recently received considerable attention in the research community. These relevant security issues are fundamentally different from those of wireline networks due to the special characteristics of wireless multi-hop networks, such as the limited energy resources and the lack of centralized control. These issues are extremely hard to cope with due to the absence of trust relationships between the nodes. To enhance security in wireless multi-hop networks, this dissertation addresses both MAC and routing layers misbehaviors issues, with main focuses on thwarting black hole attack in proactive routing protocols like OLSR, and greedy behavior in IEEE 802.11 MAC protocol. Our contributions are briefly summarized as follows. As for black hole attack, we analyze two types of attack scenarios: one is launched at routing layer, and the other is cross layer. We then provide comprehensive analysis on the consequences of this attack and propose effective countermeasures. As for MAC layer misbehavior, we particularly study the adaptive greedy behavior in the context of Wireless Mesh Networks (WMNs) and propose FLSAC (Fuzzy Logic based scheme to Struggle against Adaptive Cheaters) to cope with it. A new characterization of the greedy behavior in Mobile Ad Hoc Networks (MANETs) is also introduced. Finally, we design a new backoff scheme to quickly detect the greedy nodes that do not comply with IEEE 802.11 MAC protocol, together with a reaction scheme that encourages the greedy nodes to become honest rather than punishing them.

Download or read book Performance Evaluation and Enhancements of the MAC Layer for Multi rate SISO and MIMO IEEE 802 11 Wireless LANs written by Osama Abu-Sharkh and published by . This book was released on 2006 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Characterizing the Interaction Between Routing and MAC Protocols in Ad Hoc Networks written by and published by . This book was released on 2002 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: We empirically study the effect of mobility on the performance of protocols designed for wireless ad-hoc networks. An important objective is to study the interaction of the Routing and MAC layer protocols under different mobility parameters. We use three basic mobility models: grid mobility model, random waypoint model, and exponential correlated random model. The performance of protocols is measured in terms of (i) latency, (ii) throughput, (iii) number of packets received, (iv) long term fairness and (v) number of control packets at the MAC and routing layer level. Three different commonly studied routing protocols are used: AODV, DSR and LAR1. Similarly three well known MAC protocols are used: MACA, 802.1 1 and CSMA. Our main contribution is simulation based experiments coupled with rigorous statistical analysis to characterize the interaction of MAC layer protocols with routing layer protocols in ad-hoc networks. From the results, we can conclude the following: e No single MAC or Routing protocol dominated the other protocols in their class. Probably more interestingly, no MAURouting protocol combination was better than other combinations over all scenarios and response variables. 0 In general, it is not meaningful to speak about a MAC or a routing protocol in isolation. Presence of interaction leads to trade-offs between the amount of control packets generated by each layer. The results raise the possibility of improving the performance of a particular MAC layer protocol by using a cleverly designed routing protocol or vice-versa. Thus in order to improve the performanceof a communication network, it is important to study the entire protocol stack as a single algorithmic construct; optimizing individual layers in the seven layer OS1 stack will not yield performance improvements beyond a point. A methodological contribution of this paper is the use of statistical methods such as analysis of variance (ANOVA), to characterize the interaction between the protocols, mobility patterns and speed. Such methods allow us to analyze complicated experiments with large input space in a systematic manner.

Download or read book A MAC Layer Protocol for Wireless Ad hoc Networks Using written by Sultan Budhwani and published by . This book was released on 2011 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: Using directional antenna in ad hoc networks, offer many benefits in contrast to their classical omni-directional counterparts. The most important benefits are the significant improvement in spatial reuse, reduction of the radio interference, increase in coverage range and subsequently an increase in network capacity on the whole. On the other hand, directional transmission increases the hidden terminal problem and the problem of deafness. To best utilize directional antennas, a suitable Medium Access Control (MAC) protocol must be designed. Current MAC protocols, such as the IEEE 802.11 standard for Wireless LANs, assume the omni-directional antenna at its Physical layer and thus do not fully exploit the capabilities of a directional antenna. In this thesis, we propose a MAC protocol for wireless ad hoc networks which fully exploits the potentials of directional antennas. The first part of our design studies the issues related to directional MAC protocols and we use this knowledge to carefully design the proposed MAC protocol for ad hoc networks using directional antennas. We evaluate our work through simulation studies performed on the network simulator - NS2. Numerical results obtained are promising and show that our protocol offers significant improvement in throughput when compared to the performance of traditional 802.11 MAC protocol and D-MAC which is a Directional MAC protocol for ad hoc networks.

Download or read book Routing Algorithms for Ad Hoc Wireless Networks with a Realistic Physical Layer written by Johnson Kuruvila and published by . This book was released on 2006 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Performance Evaluation of a Mac Protocol for Hybrid Wireless Networks written by Rajesh Verma and published by LAP Lambert Academic Publishing. This book was released on 2014-12-22 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt: In recent years, due to basic features of MANETs and bandwidth constraint at MAC layer the throughput, delay and maintaining connectivity has been a major focus for research. Here, different issues of MAC protocols and TCP connectivity have been surveyed in detail. Further, channel utilization can be maximized by employing spatial reuse of the wireless channel at the MAC layer. A high throughput MAC protocol called Multiple-Beam Antenna Array MAC (MBAA-MAC) is proposed and analyzed for MANETs. Proposed MBAA-MAC protocol has been simulated to evaluate its performance in terms of throughput and delay under different network topology scenarios. Again, using this protocol, multiple concurrent transmissions are scheduled to improve the aggregate throughput of the network. The conventional MANETs provide communication in a limited geographical area. This was one of the major limitations of MANETs. A hybrid model is also proposed which is a combination of static & mobile nodes. The MBAA-MAC operates on static nodes. A grid topology consisting of chain of nodes has been simulated for different concurrent transmissions

Download or read book Ad Hoc Wireless Networks Architectures And Protocols written by Murthy and published by Pearson Education India. This book was released on 2004-09 with total page 884 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Advanced Routing Protocols for Wireless Networks written by Miguel Elias Mitre Campista and published by John Wiley & Sons. This book was released on 2014-06-02 with total page 149 pages. Available in PDF, EPUB and Kindle. Book excerpt: This text introduces the principles of routing protocols and metrics as they affect wireless networking environments, specifically in urban areas. Timely because of the recent rise in small city life, this topic includes the consideration of ad hoc, mesh, vehicular, sensor, and delay tolerant networks. These approaches are each unique, and author Miguel Mitre Campista provides a thorough, but accessible, explanation of their individual characteristics for engineers, computer scientists, IT professionals, and curious Internet users.

Download or read book Performance Evaluation of Routing Protocols in Wireless Ad Hoc Networks with Service Differentiation written by Semra Yılmaz and published by . This book was released on 2003 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Design Analysis and Performance Evaluation of a Slotted time Mac protocol for Ad hoc Wireless Networks written by Nikhil Singh and published by . This book was released on 2004 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A New Routing Protocol for Ad Hoc Wireless Networks Design Implementation and Performance Evaluation written by Idris Skloul Ibrahim and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: