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Mobile Ad hoc Networks (MANETs) are self-organized and fully distributed networks that rely on the collaboration of participating devices to route data from source to destination. The MANET paradigm is expected to enable ubiquitous mobile communication and thus the proliferation of pervasive applications. The MANET Working Group (WG) of the Internet Engineering Task Force (IETF) is responsible for standardizing an appropriate Internet Protocol (IP) based routing protocol functionality for both static (mesh) and dynamic (mobile) wireless ad hoc network topologies. In this paper, we provide a background on the possibility to use MANETs for enabling future pervasive internet and innovative ubiquitous services. We also describe the work achieved by the MANET WG thus far on the area of secure unicast and multicast routing for MANETs. We also examine non-IETF work on this area, chiefly based on adaptive and hybrid routing. The paper then presents comparative performance evaluations of discussed routing protocols. It is mainly observed that there is a need for adaptive hybrid routing approaches in order to support future innovative and pervasive applications. Consequently, we present our conclusions. [ABSTRACT FROM AUTHOR]

Due to the continuous mobility of hosts, an ad hoc network suffers from frequent disconnections. This phenomenon is undesirable when mobile hosts are accessing data from each other, and thus, data accessibility is lower than that in conventional fixed networks. Because one cannot control network disconnections, an alternative solution to this problem is to replicate data objects onto mobile hosts so that when disconnections occur, mobile hosts can still access data. In this paper, a mathematical model for data object replication in ad hoc networks is formulated. The derived model is general, flexible and adaptable to cater for various applications in ad hoc networks. We prove that this problem in general is NP-complete and propose a game theoretical technique in which players (mobile hosts) continuously compete in a non-cooperative environment to improve data accessibility by replicating data objects. The technique incorporates the access frequency from mobile hosts to each data object, the status of the network connectivity, and communication costs. In the proposed scheme, players (mobile hosts) compete through bids in a non-cooperative environment to replicate data objects that are beneficial to themselves and the system as a whole. To cater for the possibility of cartel type behavior of the players, the scheme uses the Vickrey payment protocol that leaves the players with no option than to bid in such a fashion that is beneficial to the system as a whole. The paper also identifies some useful properties of the proposed scheme and the necessary conditions of optimality. The proposed technique is extensively evaluated against some well-known ad hoc network replica allocation methods, such as: (a) randomized, (b) extended static access frequency, (c) extended dynamic access frequency and neighborhood, and (d) extended dynamic connectivity grouping. The experimental results reveal that the proposed approach outperforms the four techniques in solution quality and projects a competitive execution time. [ABSTRACT FROM AUTHOR]

This paper proposes a new multi-channel Medium Access Control (MAC) protocol named as Dual Reservation Code Division Multiple Access (CDMA) based MAC protocol with Power Control (DRCPC). The code channel is divided into common channel, broadcast channel and several data channels. And dynamic power control mechanism is implemented to reduce near-far interference. Compared with IEEE 802.11 Distributed Coordination Function (DCF) protocol, the results show that the proposed mechanism improves the average throughput and limits the transmission delay efficiently. [ABSTRACT FROM AUTHOR]

Transmission Control Protocol (TCP) optimization in Mobile Ad hoc NETworks (MANETs) is a challenging issue because of some unique characteristics of MANETs. In this paper, a new end-to-end mechanism based on multiple metrics measurement is proposed to improve TCP performance in MANETs. Multi-metric Measurement based Enhancement of TCP (MME-TCP) designs the metrics and the identification algorithm according to the characteristics of MANETs and the experiment results. Furthermore, these metrics are measured at the sender node to reduce the overhead of control information over networks. Simulation results show that MME-TCP mechanism achieves a significant performance improvement over standard TCP in MANETs. [ABSTRACT FROM AUTHOR]

Multiple-input multiple-output (MIMO) technologies have been shown to potentially improve the performance of network. Many traditional medium access control (MAC) protocols, such as spatial time division multiple access (STDMA), may not support MIMO technologies directly and not make full use of the feature of MIMO, which may be a limitation in the practical application in ad hoc networks. Therefore, in this paper, we propose a dynamic time slot allocation and stream control for MIMO STDMA (DTSMS) protocol to improve STDMA in performance. Utilizing stream control technology of MIMO and reservation scheme, DTSMS makes improvement on network throughput and avoids the mutual interference of neighbor links. Thus, DTSMS can support both unicast and multicast simultaneously. Moreover, we implement the dynamic time slot allocation scheme in DTSMS to guarantee the transmission efficiency of packets with high cross-layer transmission parameters, such as the packet priority, neighbor node density, or link quality. Utilizing the collected cross-layer information, the proposed scheme allocates time slots for all nodes dynamically according to the changes of network topology and nodes' transmission parameters. Finally, the effectiveness of the protocol is demonstrated by numerical analysis and simulations. The results show that DTSMS outperforms STDMA in terms of network throughput and delay. Furthermore, compared to our previous TTS-MIMO, DTSMS can decrease the delay of packets with high transmission parameters and improve the quality of service (QoS). [ABSTRACT FROM AUTHOR]

The scheduling algorithm is a fundamental design problem to allocate resources amongst different entities in distributive wireless sensor networks (WSNs). These sensor nodes have limited power and non-replenishable energy resources. In WSNs, the duty cycling mechanism is commonly used to save energy due to idle listening. On the other hand, a fixed duty cycling mechanism increases transmission latency in WSNs. Therefore, in order to ensure the prolonged network-life of WSNs, the medium access control (MAC) protocol should be tackled in an efficient manner to improve energy efficiency by minimizing idle listening, maximizing sleep duration, and eliminating data collision. This paper proposes a practical Adaptive Sleep Efficient Hybrid Medium Access Control (AEH-MAC) algorithm in which the key idea is to dynamically adjust nodes' sleep time to improve the scheduling in WSNs. The AEH-MAC allows nodes to adjust sleep time dynamically according to the traffic load and coordinate wakeup time with neighbour nodes. A series of short taken packets are transmitted to wake the receiver, and a prediction field is introduced in the ACK packets (GRANT/RELEASE) to reduce the waiting time of the source node. In the proposed algorithm, each node maps a conflict-free time slot for itself up to two-hop neighbouring nodes. The simulation results show that the AEH-MAC algorithm achieves high performance in terms of runtime, number of rounds, energy consumption, and slot reservation. [ABSTRACT FROM AUTHOR]

Ultra wideband (UWB) systems are considered as the key wireless infrastructure platforms for efficient short-range communications. In particular, the UWB based mobile computing systems are envisioned to be attractive solutions to various ad hoc networking applications. However, due to UWB’s unique physical characteristics, the traditional resource management schemes for ad hoc networks cannot be applied to UWB based systems directly. In this paper, we consider the bandwidth scheduling problem in a UWB based hierarchical wireless ad hoc network, which is typically used in an enterprise-scale mobile computing environment. Based on the mathematical analysis and the computer simulations, it is demonstrated that our proposed scheduling scheme exhibits close-to-optimal performance governed by the proportional fairness (PF) constraint. Moreover, a novel self-organized clustering method is designed to improve the system throughput while meeting the PF constraint. Simulation results suggest that the proposed clustering method is effective under various system configurations. [ABSTRACT FROM AUTHOR]

Media streaming delivery in wireless ad hoc networks is challenging due to the stringent resource restrictions, potential high loss rate and the decentralized architecture. To support long and high-quality streams, one viable approach is that a media stream is partitioned into segments, and then the segments are replicated in a network and served in a peer-to-peer (P2P) fashion. However, the searching strategy for segments is one key problem with the approach. This paper proposes a hybrid ants-like search algorithm (HASA) for P2P media streaming distribution in ad hoc networks. It takes the advantages of random walks and ants-like algorithms for searching in unstructured P2P networks, such as low transmitting latency, less jitter times, and low unnecessary traffic. We quantify the performance of our scheme in terms of response time, jitter times, and network messages for media streaming distribution. Simulation results showed that it can effectively improve the search efficiency for P2P media streaming distribution in ad hoc networks. [ABSTRACT FROM AUTHOR]

In this paper, based on the inherent characteristic of the contention relation between flows in ad hoc networks, we introduce the notion of the link’s interference set, extend the utility maximization problem representing congestion control in wireline networks to ad hoc networks, apply the penalty function approach and the subgradient method to solve this problem, and propose the congestion control algorithm Penalty function-based Optical Congestion Control (POCC) which is implemented in NS2 simulator. Specifically, each link transmits periodically the information on its congestion state to its interference set; the session at each source adjusts the transmission rate based on the optimal tradeoff between the utility value and the congestion level which the interference set of the links that this session goes though suffers from. MATLAB-based simulation results showed that POCC can approach the globally optimal solution. The NS2-based simulation results showed that POCC outperforms default TCP and ATCP to achieve efficient and fair resource allocation in ad hoc networks. [ABSTRACT FROM AUTHOR]

Due to recent advancements in mobile computing and communication technologies, mobile ad hoc computational Grids are emerging as a new computing paradigm, enabling innovative applications through sharing of computing resources among mobile devices without any pre-existing network infrastructure. Energy-efficient resource allocation is one of the key issues in mobile ad hoc computational Grids due to limited battery life of mobile nodes. To reduce energy consumption, we propose a hybrid power-based resource allocation scheme for allocation of interdependent tasks to nodes within mobile ad hoc computational Grid. The basic idea is to exploit dependencies and task type, and allocate interdependent tasks to nodes accessible at minimum transmission power. We also propose a power-based algorithm to search a group of closest nodes to allocate a set of interdependent tasks. Compared to traditional algorithms, complexity of proposed algorithm depends on number of transmission power levels rather than number of nodes within a Grid. The scheme is validated in a simulation environment using various workloads and parameters. [ABSTRACT FROM AUTHOR]

ggregate signatures are a useful primitive which allows aggregating many signatures on different messages computed by different users into a single and constant-length signature and adapts to Mobile Ad hoc NETwork (MANETs) very much. Jumin Song, et al. presented an ID-based aggregate signature, applied it to MANETs and proposed a secure routing scheme. In this work, we analyze Jumin Song, et al.'s aggregate signature scheme and find some limitations on its batch verification. In addition, in this work, we apply Craig Gentry, et al.'s ID-based aggregate signature to on-demand routing protocol to present a secure routing scheme. Our scheme not only provides sound authentication and a secure routing protocol in ad hoc networks, but also meets the nature of MANETs. [ABSTRACT FROM AUTHOR]