Rate adaptive video transmission over ad-hoc networks

In GPS-denied environments, accurate node localization is vital for mobile ad hoc networks (MANETs) across various applications, including disaster detection, factory automation, and security. In multi-hop MANETs, some nodes depend on imprecise neighbor nodes as dynamic anchors for cascaded localization because of insufficient base anchors. Due to inaccurate dynamic anchors and node flip ambiguity resulting from non-rigidly distributed dynamic anchors, the current Time of arrival (TOA) method suffers from the exponential growth of cascaded errors in distributed scenarios. The global Cramér-Rao lower bound (CRLB) based on the whole network can be employed for precise anchor analysis. However, the practically accessible information for distributed nodes is insufficient to retrieve the global CRLB. Accordingly, we first derive an approximate but effective local CRLB to restore the global results using limited single-hop information. Aided by this analysis, a multiple maximum likelihood estimator (MMLE) is devised to obtain high-precision dynamic anchors. Finally, we construct error circles with local CRLBs to mitigate flip ambiguity in dynamic changes and propose an advanced iterative Chan-PSO method based on CRLBs (ICPC) for TOA localization. Simulation results validate the robustness of our method in approximating the global CRLB of the target node and controlling linearly cascaded errors in multi-hop distributed MANETs.

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

Reputed Packet Delivery Using Efficient Audit Misbehaviour Detection and Monitoring Method in Mobile Ad Hoc Networks

Evolutionary algorithms are metaheuristic algorithms that provide quasioptimal solutions in a reasonable time. They have been applied to many optimization problems in a high number of scientific areas. In this survey paper, we focus on the application of evolutionary algorithms to solve optimization problems related to a type of complex network like mobile multihop ad hoc networks. Since its origin, mobile multihop ad hoc network has evolved causing new types of multihop networks to appear such as vehicular ad hoc networks and delay tolerant networks, leading to the solution of new issues and optimization problems. In this survey, we review the main work presented for each type of mobile multihop ad hoc network and we also present some innovative ideas and open challenges to guide further research in this topic.

This paper presents an intelligent early packet discard (I-EPD) for RTP-based video streaming over a multi-hop MANET (mobile ad hoc network). In a multi-hop MANET, the quality of transferring real-time video streams could be seriously degraded, since every intermediate node (IN) functionally like forwarding device does not possess large buffer and sufficient bandwidth. Even worse, a selected forwarding node could leave or power off unexpectedly which breaks the route to destination. Thus, a video packet temporarily buffered in ad hoc nodes may exceed its end-to-end jitter constraint when either a congested or failed link occurs; a stale video packet is useless even if it can reach destination after network traffic becomes smooth or failed route is reconfigured. In the proposed I-EPD, an IN can intelligently determine whether a buffered video packet should be discarded based on an estimated time constraint which is calculated from the RTP timestamps and the round trip time (RTT) measured by RTCP For the purpose of validation, we implement the I-EPD scheme on a Linux-based embedded system to demonstrate that with I-EPD buffer utilization on IN can be more effective and unnecessary bandwidth wastage can be avoided.

Broadcasting is an indispensable operation for multi-hop mobile ad hoc network (MANET) to provide control or routing functionalities. In MANET, since a packet relayed by any node can reach all its neighbour nodes, broadcasting by flooding is inefficient and results in many redundant relays. In this paper, we analyze the deficiencies of some previous broadcasting protocols and propose two enhanced lightweight protocols, namely hop count-aided broadcasting (HCAB) and self-adaptive probability broadcasting (SAPB). The proposed protocols can reduce broadcasting redundancy significantly and guarantee high broadcasting coverage as well. More importantly, the proposed protocols are lightweight, which means each node makes relay decision without any knowledge of its neighbours. Thus, the proposed protocols have low overhead and are attractive to capacity limited mobile devices. Simulation results show that the proposed protocols eliminate unnecessary relay efficiently and outperform the existing lightweight broadcasting protocols

The (MANET) ad-hoc mobile network is an automated, network in which android systems link to wireless devices. Ad hoc word means "for this purpose". In MANET any device can easily move in various directions. MANETs (Mobile Ad Hoc Networks) are the basics of broadband networks. In MANET network user can link and get connected anywhere, anytime through communication. MANET introduces a new co system for communication. MANET does not require a fixed structure relies on unconnected ports for service transportation delivery. The temporary hoc network is not dependent on mobile devices (android phones, laptop, PCs, sensors, etc.) that connect exclusively to wireless connectors. Ad-hoc work on a distributed system to provide the required network performance when there is no fixed structure. In this network, it acts as a standalone network or with many attachment points on mobile networks. This paper provides view on the features, applications of ad hoc networks, characteristics and various attacks and challenges faced by programmers and Users . We analyze MANET security objectives and will outline the features, structure, types and challenges of research and the latest trend analysis presented on Mobile Ad Hoc Network to explore open-ended issues in developing navigation strategies for MANET.

We propose a routing mechanism with distributed Call Admission Control (CAC) algorithms for Mobile Ad hoc Networks (MANET) based on IEEE 802.11e EDCA MAC protocol. A new flow can be admitted by the network only if it can find a path to sustain its traffic. Bloom filter is used here to detect the flows via each node, and the CAC routing decisions are made according to the number of flows of each node. Simulation results show that with our distributed CAC algorithm, the existing flows can be well protected in multi-hop MANET; the new added flows can make good use of the bandwidth resources without affecting the neighbor flows. Due to the space-efficient character of Bloom filter, it can be properly used in MANET, whose nodes have limited storage space and computational ability.

Power control algorithms for mobile ad hoc networks

An ad-hoc Wireless Local Area Network (WLAN) is a network without infrastructure connectivity where different types of hosts (nodes) exist; such as PDAs (personal digital assistants), laptops and cellular phones. These nodes are equipped with short range transmitters and receivers, and antennas which may be Omni directional (broadcast), highly directional (Point-to-point), or a combination of the two. A Mobile Ad hoc Network (MANET) is a collection of mobile hosts that move in different directions and speeds without the need to maintain connectivity with existing network infrastructure. Different routing protocols have been designed since the existence of ad hoc networks. This work presented below proposes a new routing protocol for ad hoc networks which aims to reduce network overhead, power consumption, Multi-user Interference (MUI), and provide link reliability. In recent years, a vast research has been seen going on in the field of Mobile Ad Hoc Networks (MANETs). Due to limited resources in MANETs, to design an efficient and reliable routing strategy is still a challenge. An intelligent routing strategy is required to efficiently use the limited resources. Also the algorithms designed for traditional wired networks such as link-state or distance vector, does not scale well in wireless environment

Trust and reputation systems play an important role in collaborative operations in mobile ad hoc networks. However, the security of trust and reputation system itself is threatened by the existence of selfish nodes. Selfish nodes can make passive attacks on the foundational process of trust and reputation system, the recommendation acquisition, through non cooperation of packet forwarding and recommendation rendering. Existing trust and reputation systems commonly suffer from vulnerability caused by the failure of recommendation acquisition which refers to the unsuccessful recommendation information obtaining from one node to another node. A credit-based mechanism is proposed to address this problem by offering credits as incentives to both intermediate nodes and recommendation render nodes. Furthermore, competition between selfish nodes is explored to prevent selfish nodes being paid excessive credits. Simulation results show that the proposed mechanism can effectively improve the success rate of recommendation acquisition and lower the total paid payoffs.

It is our great pleasure to welcome you to the 3rd ACM Workshop on Security of Ad Hoc and Sensor Networks (SASN'05), held in conjunction with the 12th ACM Conference on Computer and Communications Security (CCS'05), November 7, 2005, in Alexandria, Virginia.This year we received a total of 39 submissions on various aspects of ad-hoc and sensor network security. The program committee selected 6 as regular papers that cover a variety of topics, including trust establishment in Mobile Ad-Hoc Networks (MANETs), security of vehicular ad-hoc networks, secure group communication, key pre-distribution for sensor networks, jamming attacks against sensor network MAC protocols, and defense against Denial-of-Service (DoS) attacks. This year we continue the tradition of SASN'03 and SASN'04 to encourage the presentation and discussion of work-in-progress on ad-hoc and sensor network security. Among the 39 submissions, the program committee selected 7 papers to present in work-in-progress sessions, covering topics on anonymous routing for MANETs, key distribution for inter-group multicast in ad-hoc networks, improved topology assumptions for threshold cryptography in MANETs, RFID security, tracing in mobile wireless sensor networks, time synchronization attacks in sensor networks, and coordinated deployment for improving secure communications and sensing coverage in wireless sensor networks. In addition, the program includes a panel on Advances in Sensor and Ad-hoc Network Security and an invited keynote talk by Radha Poovandran (University of Washington) on Information Assurance in MANETs and Wireless Sensor Networks. We hope that these proceedings will serve as a valuable reference for security researchers and developers.

This paper proposes a mathematical framework to model and analyze the energy consumption of routing protocols in multihop wireless networks such Mobile Ad Hoc Networks (MANETs) or Sensor Networks (WSNs) by taking into account the protocol parameters, the traffic pattern and the network characteristics defined by the medium channel properties, the dynamic topology behavior, the network diameter and the nodes density. Moreover, our framework allows to classify routing protocols by exploring the relationship between application requirements and wireless network features. To the best of our knowledge, there is no such proposed framework that provides in-depth an analytical investigation of above relationship. We apply this model to a Beacon-less routing protocol Pizza-Forwarding (PF) compared to well known routing protocols such as Optimized Link State Routing, Ad Hoc On Demand Distance Vector Routing, Greedy Perimeter Stateless Routing and a Simple Random Walk Routing in order to underline their behavior according to the network features and application requirements. Finally, we show that Beacon-less routing protocol should be a best candidate to save energy in WSNs.

Clock synchronization is very important for power management protocol in a multi-hop MANET. However, since MANET is a network temporarily formed by a collection of mobile nodes without the aid of any centralized coordinator, clock synchronization is very difficult to achieve. Therefore, most of previous works on power efficiency assumed asynchronous clock. As a consequence, a mobile node will waste a lot of power and time waiting for forwarding a packet to its neighbors, due to the lack of information of wakeup times of its neighbors. In this paper, we propose a multi-hop time synchronization protocol, referred to as MTSP, for multi-hop MANETs based on IEEE 802.11 ad hoc mode. The MTSP consists of two phases: beacon window (BW) phase and synchronization (SYN) phase. In BW phase, several devices, which can directly communicate with each others, form a synchronization group. And each group selects the device with fastest timer as the leader node of the group. In SYN phase, leader nodes then synchronize with each other. Our simulation results show that MTSP is a distributed and effective multi-hop time synchronization protocol, especially for dense networks.KeywordsIEEE 802.11mobile ad hoc network (MANET)multi-hoptime synchronization

Since multi-hop mobile ad hoc network (MANET) contains a set of wireless mobile nodes forming a temporary network, the topology is strongly influenced by the node mobility models. Numerous mobility models have been presented, including the Random Waypoint Mobility Model (RWMM), Manhattan Grid Mobility Model (MGMM), Freeway Mobility Model (FMM), and so on. In MGMM, the trajectories of mobile nodes are confined to a grid topology. MGMM is an important mobility model, and numerous objects following MGMM can be enumerated, such as the movement of cars in the city, the movement of people though department stores etc. The expected link life time (ELLT) is an important performance parameter in MANET. When a node wishes to transmit information to the other node directly, these two nodes must be within each other's transmission range for a period of time. This period is called the link life time (LLT). The ELLT is the expected value of LLT. The goal of this work largely focuses on identifying the ELLT of the MANET under MGMM by using mathematical analysis. Based on our observation, two nodes involved in constructing a connection under MGMM can be classified into three independent cases: namely parallel with opposite directions, parallel with same directions, and vertical cases. These three cases can be formulated independently. To verify these formulations numerous simulations are done by ns2, and the theoretical and simulation results are well matched.