A feedback based scheme for improving TCP performance in ad-hoc wireless networks

Minimizing interference of a wireless ad-hoc network in a plane

A mobile ad-hoc network (MANET) is a special type of wireless networks. It consists of a collection of mobile nodes that are capable of communicating with each other without help from a fixed infrastructure. The interconnections between nodes are capable of changing on a continual and arbitrary basis. Nodes within each other's radio range communicate directly via wireless links, while those that are far apart use other nodes as relays in a multi-hop routing fashion. The typical applications of MANETs include conferences or meetings, emergency operations such as disaster rescue, and battlefield communications. Transmission Control Protocol (TCP) [1] is a reliable, connection-oriented, full-duplex, transport protocol widely used in wired networks. TCP’s flow and congestion control mechanisms are based upon the assumption that packet loss is an indication of congestion. While this assumption holds in wired networks, it does not hold in the case of mobile wireless networks. In addition to congestion, a transport protocol in an ad hoc network must handle mobilityinduced disconnection and reconnection, route change-induced packet out-of-order delivery for mobile hosts, and error/contention prone wireless transmissions. Reaction to these events might require transport control actions different from congestion control. It might be better to periodically probe the network during disconnection than to back off exponentially [2], and it makes more sense simply to re-transmit a packet lost to random channel error than to multiplicatively decrease the current congestion window [3]. Even if the correct action is executed in response to each type of network event, it is not immediately obvious how to construct an engine that will accurately detect and classify events. Packet loss alone cannot detect and differentiate all these new network events [4]. In this paper, we first describe the necessary network states in an ad hoc network to be identified by TCP and use an end-to-end approach for identification of congestion state in ad hoc network then examine metrics that can be measured end-to-end. Two metrics are devised to detect congestion, IDD (Inter Delay Difference) and STT (Short Term Throughput).The approach we propose in this paper utilizes network layer feedback (from intermediate hops) for identification of disconnection state to put TCP sender into persist mode. Therefore we use from advantage of both end to end measurements and network layer feedback. The remainder of the chapter is organized as follows: It starts with describing TCP’s challenges in MANETs environment in Section 2. Section 3 provides an overview of related

Mobile Ad-hoc Network (MANET) has emerged as the self organized wire less interconnection for the various applications in random topology. As most of the multimedia applications require strict QoS guarantee during the communication between a single source and multiple destinations. How ever, achieving reliable multicast transmission in MANET is crucial due to the dynamic network topology caused by the node mobility. This gives rise to the need for an efficient multicast routing strategy. This paper proposes a novel scheme PBMRP-BR (position-based Multicast Routing Protocol for Ad-hoc Network Using Backpressure Restoration) for efficient transmission of multimedia applications in Ad-hoc Network, which provides priorities for routing based on Distance of path, Load at the node (ie, traffic) and queue length at the node(ie, bandwidth). It also keeps the path information including bandwidth resources of each node for routing decisions. The problem of the link failure in the channel during the call in progress thus lead in the degradation of the QoS (Quality of Service).To deal this we are using a Backpressure Technique The simulation results shows that the proposed algorithm is able to find a better solution, fast convergence speed and high reliability. The simulation results shows the proposed PBMRP-BR protocol achieve the above objectives and gives the batter results than previous schemes like DSR for the maintenance of overheads and the path reliability. Our proposed scheme will improve the bandwidth utilization by reducing the congestion in the Adhoc wireless network.

Ad-hoc 네트워크 환경에서의 많은 라우팅 알고리즘들은 소스 라우팅 기법을 기초로 설계되었으며 밀집된 ad-hoc 환경에서의 최단경로설정은 짧은 기간동안만 유지되는 제약사항이 존재한다 때문에 SSA와 ABR과 같은 라우팅 프로토콜은 링크 안정성을 고려하여 좀더 안정적인 경로를 탐색한다. 본 논문은 Ad-Hoc network 환경에 현실적으로 적합한 SSA 라우팅 알고리즘을 바탕으로 utilization 메트릭을 고려한 새로운 라우팅 기법에 대해 제안한다. 제안된 방식에서는 SSA의 특정 메트릭에 의한 병목현상을 해결하기 위해 연결을 위한 여러 경로들을 누적 utilization에 따라 분산시키도록 하여 네트워크상의 로드 밸런싱을 추구하였다. 성능 분석을 위해 기존의 라우팅 기법인 AODV와 SSA를 참고 비교 대상으로 하였다. ns-2 네트워크 시뮬레이션 결과 선택되어질 수 있는 안정적인 route가 많은 경우 전체 트래픽이 여러 경로들로 분산되어 경로 재설정(route reconstruction) 횟수를 현저히 줄이는 좋은 성능을 보였다 Many routing algorithms, proposed for ad-hoc wireless networks, we based on source routing scheme and shortest path route has short lifetime especially in highly dense ad-hoc wireless networks. So some routing protocols such as SSA and ABR are considering the link stability and try finding more stable route. In this paper we propose a new routing algorithm considering utilization metric based on SSA routing algerian in Ad-Hoc networks. To reduce the bottleneck by specific metric of SSA, proposed scheme makes load balancing in networks by distributing the connections to several routes. For the evaluation of the performance we compare our scheme with existent routing protocol AODV and SSA. And the results, obtained using the ns-2 network simulation platform, show good performance that reduced the number of reconstructions remarkably by distributing the whole traffic to several routes when there are several stable routes.

Recent development has a tremendous growth in the ad-hoc wireless networks. Ad-hoc wireless networks are dynamic topology networks organized by a collection of mobile nodes that utilize multi-hop radio relaying and are capable of operating without the support of any fixed infrastructure. Ad-hoc wireless networks are very useful in emergency operations, collaborative and distributed computing and military applications. Multicasting plays an important role in the ad-hoc wireless networks, where nodes form groups to carry out certain tasks that require point-to-multipoint and multipoint-to-multipoint voice and data communication. The biggest challenge in the ad-hoc wireless networks is to find an optimized path between the two nodes. In this paper, we present an ant colony based metaheuristic multicast routing protocol for ad-hoc wireless networks, in that we analyzed the performance of dynamic core based multicast routing protocol (DCMP). This approach maps the solution capability of swarm intelligence to mathematical and engineering problems. The DCMP is highly adaptive, efficient and scalable. The performance of these protocols has been examined under realistic scenarios using NS 2, the network simulator tool. Performance has been analyzed for the metrics packet delivery ratio and control overheads with the multicast routing protocol. The proposed ant colony based routing protocol reduce the overheads in routing.

An ad-hoc wireless network is formed by a number of mobile nodes having limited communication range. The dynamic source routing (DSR) protocol is frequently used to extend the effective range of these nodes through mutual cooperation. The accurate execution of the DSR protocol demands sustained benevolent behaviour by all participating nodes. However, as ad-hoc networks are created in improvised environments, the realization of such altruistic behaviour is virtually impossible to achieve. In fixed networks, trust infrastructures like certification authorities and key distribution centres are generally used to provide default trust relationships. However, the creation of such an entity in an ad-hoc network is considered neither feasible nor pragmatic. In this paper, we propose a novel mechanism for establishing trust based routing in ad-hoc networks without necessitating a trust infrastructure. We accentuate, that the proposed mechanism is most suitable for ad-hoc networks that can be created on the fly without making any suppositions or imposing pre-configuration requirements.

VANET (Vehicular Ad-hoc Network) is an ad-hoc wireless network which nodes are composed by mostly moving vehicles and infrastructure communications or access points along the road. It integrates adhoc networking, cellular technology, wireless LAN and other technologies, which include GPS(Global Positioning System), digital mapping, sensing technologies and advanced information processing tools to support Intelligent Traffic Systems (ITS). VANET is developed mainly to improve road safety and to increase the traffic efficiency. It is designed to support the exchange of warning messages among the vehicles to increase the passenger safety and other information related to VANET applications and services . To achieve these goals, there are several issues that should be addressed. One of these challenges is designing reliable and efficient Medium Access Control (MAC) protocol for VANET. Due to VANET’s distinguishing characteristics, such as high mobility of the nodes, dynamic network topology, enough battery power, high processing power, etc, the MAC protocols designed for MANET (Mobile Ad-hoc Network) are not suitable for VANET. The research community has been working to develop MAC protocols appropriate for this ad-hoc network by proposing new design or modifying the existing one.In this paper, the VANET’s architecture, characteristics, applications and standard are discussed and then a comprehensive study of several MAC protocols available in the literature is presented.

The TCP protocol exhibits poor performance in multi-hop Mobile Ad Hoc Networks (MANETs). The ultimate reason for this is that MANETs behave in a significantly different way from traditional wired networks (like the Internet) for which the TCP protocol was originally designed. In particular, route failures and route changes due to node mobility may be frequent events in MANETs. Furthermore, congestion phenomena in MANETs are essentially different from traditional wired networks. In this paper we propose a novel transport protocol for MANETs. Unlike other proposals, our protocol is not a modification of the TCP but is specifically tailored to the characteristics of the MANET environment. It is able to manage efficiently route changes and route failures. Furthermore, it includes a completely re-designed congestion control mechanism. Finally, it is designed in such a way to reduce as much as possible the number of useless retransmissions. This is extremely important since retransmissions consume energy.KeywordsAd Hoc NetworksMobilityTransport ProtocolsTCP

Modern Wireless Local Area Networks (WLANs) with relatively high data rates have become an attractive technology for providing Internet connectivity for mobile users. Ad-hoc networks are a collection of mobile nodes that can be deployed without the need for any centralized management infrastructure. In such a set-up, to establish the required communication paths, each node must be willing to act as a potential router. In practice though, some nodes may act selfishly and refuse to forward packets. In Ad-hoc networks, a node may be considered as misbehaving for different reasons, for instance when it acts selfishly, refusing to forward packets. In some circumstances, the node can be overloaded, or they simply want to save their resources by not forwarding packets unless they are of direct interest to the node itself. Conversely, these nodes may still be expecting others to forward packets on their behalf. In this paper, we report the experimental results obtained from a typical Ad-hoc networks that contain selfish nodes. We also analyze the behavior of the nodes, to establish some quantifiable measure of their reliability. Such measures, based on the behavior history of the nodes, are then utilized to improve the performance and reliability of the widely used Ad-hoc On Demand Distance Vector routing protocol. We also report the results of simulations of large Ad-hoc networks in the presence of malicious or selfish nodes. These results clearly indicate the capabilities of the proposed approach in discovering communication paths with a minimal number of malicious or selfish nodes.

The year 2005 witnesses the third occasion that the Wireless Personal Area and Ad-hoc Networks minitrack is part of the annual HICSS conference. This year there was a substantial increase in submissions (thus a substantial decrease in the acceptance rate), indicating the growing importance of research in this area. The minitrack is also focused on fundamental challenges and issues arising in wireless sensor networks and their applications. Wireless sensor networks differ from other wireless networks in the need for unattended and very low-energy operation, in the possibility of collaboration and distributed sensor calibration, and in the mission oriented nature of most sensor networks. Thus our mini track looks at two very important streams of research. After a strict review process nine papers were selected to be included in the program of the minitrack. The first paper is titled “BT-Crowds: Crowds-style Anonymity with Bluetooth and Java,” presenting an interesting idea on how anonymity can be achieved when sending messages in WPAN environments. Our second paper revisits scatternet formation issues of Bluetooth based ad hoc networks thus the title: “A Dynamic and Distributed Scatternet Formation Protocol for Real-life Bluetooth Scatternets.” The third paper is titled “Secure Dynamic Source Routing” and presents a new variant of the DSR routing protocol with special emphasis on security. In the fourth paper, the discussion concerns “Routing Based Feedback towards Applications in Mobile Ad Hoc Networks,” where routing notifications are relayed via event channels. “A Location Service Mechanism for Position-Based Multicasting in Wireless Mobile Ad hoc Networks” is the title of the fifth paper in the minitrack. It presents some innovative ideas on how location information can be managed for multicast communications in ad-hoc networks. In the sixth paper, “Sliding Window Protocol for Secure Group Communication in Ad Hoc Networks,” the authors propose a sliding window protocol for determining multiple routes in a multi-communications environment. In the seventh paper titled “Ad Hoc Routing Protocol Avoiding Route Breaks Based on AODV,” the authors propose improvements to the well-known AODV ad hoc routing protocol The eight paper, “Joint Scheduling and Routing Algorithm for Ad Hoc Wireless,” presents an innovative and interesting idea wrapped around an iterative algorithm on power control. In the final paper of the minitrack, “Performance Issues of Ad Hoc Routing Protocols in a Network Scenario used for VideoPhone Applications,” the authors present a simulation based performance analysis of different ad hoc routing protocols using the application pointed to in the title. These papers highlight some of the issues and work towards solutions in Personal Area and ad hoc networks which are among the most active research fields in wireless networking. We believe that the papers will provide opportunities for researchers to come together and discuss and debate the results of the interesting experiments that are described in the papers. We are confident that the minitrack will achieve its goal of bringing together leading researchers, to present new results and discuss synergies between the two areas. We also take this opportunity to thank all the reviewers for their valuable and professional work as well as all the authors who submitted papers and thus helped us to create such a strong minitrack. We would also like to express our sincere gratitude to the conference organizers for their hard work and help.

Ad hoc wireless networks without central authority have attracted much attention in both academic society and industry. A key aspect of communications in such networks is the large dynamic range of interference. OFDMA (multiplexing simultaneous transmissions in different frequency tones) is an effective way of dealing with interference. On the other hand, there are many known distortions in transmit and receive chains of the communication devices, e.g. non linearity of the power amplifier, which can compromise the OFDMA orthogonality among the resources assigned to different transmissions. These distortions, together with the large dynamic range one would expect in ad hoc communications, can pose a threat to the effectiveness of communications in OFDMA ad hoc networks. In this paper, we propose and evaluate different signaling choices for communications in ad hoc networks, via both analysis and simulations. In particular, we observe that OFDMA based single tone signaling, i.e. each user transmits only on a single frequency tone, outperforms other signaling choices in many aspects.

The OSPF routing protocol is currently the predominant IGP in use on the fixed Internet of today. This routing protocol scales ''world wide, under the assumptions of links being relatively stable, network density being rather low (relatively few adjacencies per router) and mobility being present at the edges of the networks only. Recently, work has begun towards extending the domain of OSPF to also include ad-hoc networks -- i.e. dense networks, in which links are short-lived and most nodes are mobile. In this paper, we focus on the convergence of the Internet and ad-hoc networks, through extensions to the OSPF routing protocol. Based on WOSPF, a merger of the ad-hoc routing protocol OLSR and OSPF, we examine the feature of OSPF database exchange and reliable synchronisation in the context of ad-hoc networking. We find that the mechanisms, in the form present in OSPF, are not suitable for the ad-hoc domain. We propose an alternative mechanism for link-state database exchanges in wireless ad-hoc networks, aiming at furthering an adaptation of OSPF to be useful also on ad-hoc networks, and evaluate our alternative against the mechanism found in OSPF. Our proposed mechanism is specified with the following applications in mind: (i) Reliable diffusion of link-state information replacing OSPF acknowledgements with a mechanism suitable for mobile wireless networks; (ii) Reduced overhead for performing OSPF style database exchanges in a mobile wireless network; (iii) Reduced initialisation time when new nodes are emerging in the network; (iv) Reduced overhead and reduced convergence time when several wireless OSPF ad hoc network clouds merge.

Ad Hoc network is one of the popular wireless multi-hop networks. Nodes or Users in Ad Hoc network can move randomly and freely to maintain communication without the control of the fixed infrastructure. Due to the limited transmission power and wireless coverage of the terminal, if two terminals that are beyond their respective transmission radius need communicate, they must use other intermediate or relay nodes for packet forwarding, so that a wireless Ad Hoc network is formed among these nodes. In this paper, the current state-of-the-art multipath routing protocols for Ad Hoc networks are reviewed. Particularly, the pros and cons of them are analyzed. Finally, they are summarized and compared.

In recent years, with the increasing popularity of Internet technology and the advent of the 5G communication era, the applications related to mobile IoT have exploded, and wireless Ad Hoc network has received more and more attention. In traditional Ad Hoc networks, data are often transmitted between nodes in the form of "multi-hops", and the transmission range and available energy of nodes are limited. Thus, in Ad Hoc networks, a reliable and energy-efficient data transmission protocol is needed. In this paper, we studied the existing multipath routing protocols and proposed a multiple performances based routing protocol E <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> LR, ( residual Energy, Energy consumption, Loop, Routing protocol ) for the shortcomings of Ad Hoc networks. This protocol has the following improvements to the existing multi-path routing protocols: (1) In the route discovery process, depending on the energy level of the nodes, the nodes make three different decisions on the received RREQ packets: discard, randomly delayed forwarding, and immediate forwarding, to filter out the nodes with lower energy and thus improve the network performance. (2) When selecting available paths, try to select nodes whose lifetime are close to each other. This can reduce the number of interruptions in the transmission path and improve the stability of the transmission path during data transmission. (3) When transmitting data, multiple paths stored in the source node are recycled to transmit data, thus balancing the node energy. Simulation results show that the E2LR routing protocol can effectively reduce the frequency of route initiation, shorten the data transmission delay, reduce the packet loss rate in the network compared with existing multipath routing protocols.

Broadcasting is an essential operation for Wireless Ad Hoc Networks to perform routing path discovery, and it has become the predominant technology for message dissemination in Vehicular Ad Hoc Networks (VANETs). In the reactive routing schemes of wireless ad hoc network, Routing Request (RREQ) packets are broadcast from the source, and once received the destination traces back the broadcasting path to build an on-demand route. In VANETs, different broadcasting schemes have been proposed for safety, comfort, and commercial applications. However, broadcasting usually generates a lot of redundant messages which would cause excessive channel contention and packet collisions, especially when the density of the network becomes higher. In this survey article, we first introduce the most common data dissemination techniques used in wireless ad hoc networks. After that, we discuss techniques that have been proposed to mitigate the broadcast storm problem. Finally, we introduce an effective model for analyzing the broadcasting schemes, and based on the model we propose an adaptively adjusted probabilistic scheme that highly improves the reliability of broadcasting in dense ad hoc networks.