A protocol for data dissemination in frequently partitioned mobile ad hoc networks

HashQuery, a Hash-area-based data dissemination protocol, was designed in wireless sensor networks. Using a Hash function which uses time as the key, both mobile sinks and sensors can determine the same Hash area. The sensors can send the information about the events that they monitor to the Hash area and the mobile sinks need only to query that area instead of flooding among the whole network, and thus much energy can be saved. In addition, the location of the Hash area changes over time so as to balance the energy consumption in the whole network. Theoretical analysis shows that the proposed protocol can be energy-efficient and simulation studies further show that when there are 5 sources and 5 sinks in the network, it can save at least 50% energy compared with the existing two-tier data dissemination(TTDD) protocol, especially in large-scale wireless sensor networks.

Vehicular sensor networks (VSNs) have emerged as a new technology, which combines wireless communication offered by vehicular ad hoc NETworks with sensing devices installed in vehicles or in roadsides. VSN creates a huge opportunity to extend the roadside sensor infrastructure of existing traffic control systems. The main issues in VSNs are inherent in the data collection and its dissemination in such a large-scale network, characterized by frequent topology changes and network partitioning. This paper proposes a new multi-hop data collection and dissemination protocol based on data replication approach. The aim is an efficient collection and dissemination of data from a defined geographic area. Differently from other data collection protocols for VSNs, which have for purpose to collect data for traffic control applications or monitoring applications, our proposed protocol called Collaborative Data Collection Protocol (CDCP for VSNs) focuses on collecting data to be used in non-delay tolerant applications, so CDCP aims to collect the requested data within an optimized delay, but also, focuses in making this data accessible for other potential requests. Simulation results show the effectiveness of our proposed protocol.

A Vehicular Ad Hoc Network (VANET) is a subclass of Mobile Ad Hoc Networks, which provides wireless communication among vehicles as well as between vehicles and roadside units. Providing safety, traffic efficiency and user comfort for drivers and passengers are promising goals of these networks. To reach these goals many envisaged applications for VANETs will rely on data dissemination, turning this task into an essential service. However, due to some inherent characteristics of VANETs, such as intermittent connectivity, highly dynamic topology, and diverse network densities, data dissemination is a challenging activity in this kind of network. Although data dissemination has been extensively studied in the literature, existing solutions do not effectively address the broadcast storm and network partition problems when considered together. To deal with both problems, we propose a network partition-aware geographical data dissemination protocol, which eliminates the broadcast storm and maximizes the data dissemination capability across network partitions with short delays and low overhead. The proposed algorithm is able to autonomically adjust message transmissions in the network. Simulation results show that our proposed approach provides good efficiency with respect to the coverage of event processing, delay and overhead.

Structured overlay networks form a major class of peer-to-peer systems, which are touted for their abilities to scale, tolerate failures, and self-manage. Any long-lived Internet-scale distributed system is destined to face network partitions. Although the problem of network partitions and mergers is highly related to fault-tolerance and self-management in large-scale systems, it has hardly been studied in the context of structured peer-to-peer systems. These systems have mainly been studied under churn (frequent joins/failures), which as a side effect solves the problem of network partitions, as it is similar to massive node failures. Yet, the crucial aspect of network mergers has been ignored. In fact, it has been claimed that ring-based structured overlay networks, which constitute the majority of the structured overlays, are intrinsically ill-suited for merging rings. In this paper, we present an algorithm for merging multiple similar ring-based overlays when the underlying network merges. We examine the solution in dynamic conditions, showing how our solution is resilient to churn during the merger, something widely believed to be difficult or impossible. We evaluate the algorithm for various scenarios and show that even when falsely detecting a merger, the algorithm quickly terminates and does not clutter the network with many messages. The algorithm is flexible as the tradeoff between message complexity and time complexity can be adjusted by a parameter.

In this article, an optimal steady-state voltage control framework is developed based on a novel linear voltage-power dependence deducted from Gaussian process (GP) learning. Different from other point-based linearization techniques, this GP-based linear relationship is valid over a subspace of operating points and, thus, suitable for a system with uncertainties such as those in power injections due to renewables. The proposed optimal voltage control algorithms, therefore, perform well over a wide range of operating conditions. Both centralized and distributed optimal control schemes are introduced in this framework. The least-squares estimation is employed to provide analytical forms of the optimal control, which offer great computational benefits. Moreover, unlike many existing voltage control approaches deploying fixed voltage references, the proposed control schemes not only minimize the control efforts but also optimize the voltage reference setpoints that lead to the least voltage deviation errors with respect to such setpoints. The control algorithms are also extended to handle uncertain power injections with robust optimal solutions, which guarantee compliance with the voltage regulation standards. As for the distributed control scheme, a new network partition problem is cast, based on the concept of effective voltage control source (EVCS), as an optimization problem which is further solved using convex relaxation. Various simulations on the IEEE 33-bus and 69-bus test feeders are presented to illustrate the performance of the proposed voltage control algorithms and EVCS-based network partition.

For improving the traffic safety in intelligent transportation systems, vehicles that are formed by Vehicular Ad-hoc Networks (VANETs) conventionally disseminate warning messages to their nearby vehicles as soon as a dangerous situation occurs. However, the major challenge in VANETs is to develop an efficient data dissemination protocol for tackling the broadcast storm and network partition problems. In this paper, we propose an Adaptive Beacon-based Data Dissemination (ABDDis) scheme to deal with these problems using only local one-hop neighbor information. The ABDDis scheme features a novel mechanism to adaptively adjust the beacon interval to reduce the channel load while maintaining the correct information about nearby vehicles. Additionally, a novel store-carry-forward (SCF) mechanism is proposed to overcome the network partition problem. The performance of the ABDDis scheme is evaluated in the Veins simulation framework that provides a bidirectional coupling between the network simulator OMNeT++ and the traffic simulator SUMO. The simulation result shows that the ABDDis scheme significantly mitigates the broadcast storm compared to other schemes and maintains a good coverage across various traffic densities. Moreover, the ABDDis scheme shows its robustness by being able to tolerate reasonable GPS drift.

Data dissemination from multiple sources to mobile sinks is fundamental and challenging in WSN applications due to limited energy supply of sensor nodes and sink mobility. Previous data dissemination protocols either rely on an energy-consuming coordinate system or build an inefficient backbone. In this paper, we propose a hierarchical role-based data dissemination (HRDD) protocol in wireless sensor networks. In HRDD, a small number of sensor nodes are assigned to serve as cluster heads and agents to form the data dissemination backbone and mitigate unnecessary query forwarding. In addition, HRDD designs an efficient data delivery mechanism that provides shorter paths to accelerate data delivery as well as reduce the number of data transmissions. An adaptive backbone maintenance mechanism is also introduced for low-energy cluster heads and agents to reduce their load, thereby prolonging the network lifetime. The experimental results show that HRDD achieves the longer network lifetime, the shorter delay, and the high success ratio compared to the prior work.

One of the major challenges in facing the design of disseminating protocol for Wireless Sensor Networks (WSNs) is to find an energy efficiency way. Recently, several researches have been studied for this issue, and SPMS, that outperforms the well-known protocol SPIN, specially is a representative protocol. Also one of many characters of SPMS is the using of the shortest path to minimize the energy consumption. However, since it repeatedly uses the same path as the shortest path, the maximizing of the network lifetime is impossible, though it reduces the energy consumption. In this paper, we propose a novel data dissemination protocol, called Energy and Distance Aware protocol based on SPIN (EDAS), that guarantees energy-efficient data transmission and maximizes network lifetime. EDAS solves the network lifetime problem by using the residual energy and the efficient distance between nodes to determine a path for data dissemination. The simulation results show that EDAS guarantees energy-efficient transmission and moreover increases the network lifetime by approximately 69% than that of SPMS.KeywordsWireless Sensor NetworksData Dissemination ProtocolEnergy EfficiencyLifetimeSPMS

A mobile ad hoc network is a group of mobile, wireless nodes which cooperatively and spontaneously form an IP-based network. In order to make computing and communication, a node in an IP-based network must be configured with an IP address. On the other hand, the main problem in an ad hoc network is the mobility of the nodes which can lead to frequent and unpredictable topology changes (network partitions and merge). In this environment, a centralized administration is an impossible approach so automated dynamic assignment of IP addresses is a desirable goal. One key challenges to mobile ad hoc network is the resolution of addresses when two or more partitions merge. In this paper, we propose a new approach to merge partitions in a mobile network, based on an updating of DHCP (which is a protocol designed to wired network). This solution implements a new DHCP client/server, which can detect IP conflicts. Finally, we evaluate the performance of the solution through simulation experiments.

The popularity of concurrent transmissions (CT) has soared after recent studies have shown their feasibility on the four physical layers specified by BLE 5, hence providing an alternative to the use of IEEE 802.15.4 for the design of reliable and efficient low-power wireless protocols. However, to date, the extent to which physical layer properties affect the performance of CT has not yet been investigated in detail. This article fills this gap and provides an extensive study on the impact of the physical layer on CT-based solutions using IEEE 802.15.4 and BLE 5. We first highlight through simulation how the impact of errors induced by relative carrier frequency offsets on the performance of CT highly depends on the choice of the underlying physical layer. We then confirm these observations experimentally on real hardware and with varying environmental conditions through an analysis of the bit error distribution across received packets, unveiling possible techniques to effectively handle these errors. We further study the performance of CT-based data collection and dissemination protocols in the presence of RF interference on a large-scale testbed, deriving insights on how the employed physical layer affects their dependability.

YAP is a protocol designed to efficiently and robustly relay network configuration states of nodes to a designated node that collects and stores the configuration states of all the nodes. Once the configuration states from the nodes are collected, any application can query the information to perform its own specific function. For example, a GUI application can query the database to display the logical topology of the networks. Also a Configuration Manager can query the database to decide how to reconfigure the network. We describe how YAP was integrated with protocols designed to auto-configure IP-related attributes of nodes (using DRCP and DCDP).

In the literature, there exist connectivity-based distributed clustering methods called CDC (Connectivity-based Distributed node Clustering scheme) and SDC (SCM-based Distributed Clustering). CDC and SDC have mechanisms for maintaining clusters against nodes join and leave, but both methods do not assume frequent changes in the network topology. In this paper, we propose a lightweight distributed clustering method called SBDC (Schelling-Based Distributed Clustering), which is inspired by Schelling's model -- a popular segregation model in sociology. We also evaluate the effectiveness of our proposed SBDC in environment with frequent changes in the network topology. Our simulation results show that SBDC outperforms CDC and SDC under frequent changes in the network topology caused by high node mobility.

An often overlooked practical problem in Intelligent Transportation Systems (ITS) is the presence of areas without cellular network connectivity, so-called dead spots, which aggravates the communication between vehicles and the external infrastructure. In our previous work, we suggested to mitigate this problem by using a hybrid data dissemination protocol that combines cellular network communication with ad-hoc networks between vehicles. If the vehicles in such ad-hoc networks are in a dead spot but have a good estimation about the time they will leave it again, messages can be forwarded to the vehicle that is supposed to regain cellular network coverage first. Since this vehicle may transmit the stored messages immediately after having left the dead spot, the delivery time is improved. In this paper, we first analyze the behavior of the aforementioned data dissemination protocol in larger dead spots in which a message may be carried by several vehicles before being delivered via the cellular network. The analysis reveals that messages are not always delivered in the fastest possible time. To address this concern, a new protocol variant named context-aware message flooding protocol is introduced. This protocol, indeed, guarantees the fastest possible forwarding of messages to their recipients. This is achieved at the cost of delivering duplicates that, however, are only produced when the delivery of a message is sped up.

Wireless Sensor Networks (WSNs) are popular in smart homes to implement context-aware and intelligent services. Due to fixing bugs and adding new functions, the software on sensor nodes needs to be updated depending on efficient bulk data dissemination. Existing page transfer of data dissemination protocols employ pipelining technique to achieve spatial multiplexing. The conventional pipelining inefficiency, however, becomes a bottleneck in terms of dissemination delay and communication overhead. In this paper, we propose SAPM, a novel Self-Adjusting Pipelining Mechanism for efficient bulk data dissemination. By considering the impact of link correlation, detecting accumulated pages in sensor nodes, and carefully selecting the number of pages to request, SAPM shortens the dissemination delay effectively and reduces communication overhead to improve current bulk data dissemination protocols' performance. Our evaluation results on test bed experiments and extensive simulations show that SAPM reduces the completion time of state-of-the-art bulk data dissemination protocols by 27.8% on average compared to naive solution and the number of transmissions by 17.4% on average under high link correlation while having a low memory overhead.

Lifetime and energy efficiency are important factors in the design of wireless sensor network. A critical issue during data collection is the formation of energy holes near the sink. Sensors which are located near the sink have to participate in relaying data on behalf of other sensors and thus their energy will be depleted very quickly. Mobile sink movement yields the significant performance gained by decreasing the amount of energy consumption. In this paper, we propose an Intelligent Grid Based Data Disseminating protocol for mobile sink in wireless sensor networks. We have utilized a virtual grid as the protocol's substructure. In our proposed method, cell heads (CHs) will be selected based on the locations of virtual cross points (CPs) and CPs selection is needless to transfer any required data between neighbor nodes. We have optimized CPs selection using linear programming technique in order to increase network lifetime. By selecting the CHs based on our proposed algorithm, data will be disseminated toward the sink. Our data dissemination protocol is simple and has low overhead to construct and maintain. Also, we have presented a new method for sink location update which leads to the least cost in data transfer. Simulation results illustrate that by utilizing hierarchical functionality and selecting appropriate CPs and consequently selecting CHs, energy consumption will be decreased in comparison with other presented methods which directly lead to network lifetime increment. Also by determining an optimal cell size, packet delivery rate will be improved noticeably.