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ZigBee standard is a developing low-cost, low power consumption, short-distance wireless communication standard and routing algorithm improvement plays an important part in updating the protocol. Based on the analysis of existed ZigBee routing algorithm, this paper proposes an improvement by comprehensive using of Cluster-Tree algorithm and the "piggyback" technology to increase effective...
We propose a prototype for a real-world, human network proximity experiment with detailed recordings of the position of individuals. Our aim is to provide a comprehensive dataset to investigate the internal correlations between mobility and network properties, as well as to compare our results with different datasets, involving different social groups or mobile agents. As a further result, we expect...
Shadow zone and delay aware routing (SZODAR) scheme is a practical and distributed routing protocol that can find routes around shadow zones. In SZODAR, sensor nodes can raise or lower their acoustic transducers to a depth such that shadow zones of the neighboring nodes are avoided. The engineering parameters in SZODAR and their evaluations are also presented.
This paper explores the robust routing of messages among individuals. Traditional routing assumes individuals provide messages to a device connected to a communications network that assumes all responsibility for message delivery. Although each individual may have links to multiple communication devices (office computer, PDA, cell phone), messages are delivered only if there is an end-to-end communication...
We study end-to-end delay performance of different routing algorithms in networks with random failures. Specifically, we compare delay performances of differential backlog (DB) and shortest path (SP) routing algorithms and show that DB routing outperforms SP routing in terms of throughput when the network is heavily loaded and/or the failure rate is high while SP routing achieves better delay performance...
Despite ??airborne network (AN) topology design?? and careful planning of AN trajectories, unexpected disruptions (from hardware failures to changes in mission requirements and hostile attacks) may cause nodes not to connect to one another directly or indirectly either because they are out of one another's range or because nodes do not meet one another according to their preplanned trajectories. Since...
Routing for link state routing protocols such as OSPF is determined by computing shortest-paths on the network topology graph. In conventional routing the OSPF link costs are configured a-priori before the network is deployed, and remain fixed until manually changed. If subsequently, link quality degrades or alternate links become available, routing paths may become sub-optimal in terms of throughput...
In the tactical Internet, inter-domain links consist mostly of unreliable and low bandwidth wireless links. To enable seamless routing across different Autonomous Systems (ASes), we propose an inter-domain Traffic Engineering (TE) scheme to reroute traffic when congestion occurs. There are two components for the TE scheme. First, a Traffic Splitting (TS) scheme is used for load balancing among parallel...
This paper presents heterogeneity ratio (HR) as a new routing metric for heterogeneous MANETs. This metric is the ratio of number of powerful nodes to hop count that is used to select the best path to destination. Node heterogeneity is modeled in terms of: types and number of different interfaces, power, and transmission ranges. Our proposed routing metric is based on developing route discovery algorithm...
In order to ensure ubiquitous connectivity, networks have to operate in regions with very limited infrastructure support. There has been intense recent research activity in the emerging areas of intermittently connected, ad hoc, and delay/disruption tolerant networks (DTN). DTNs differ greatly, depending on the nature of the network environment; they range from deep space networks to buses driving...
Vehicular Delay-Tolerant Networks (VDTNs) are an application of the Delay-Tolerant Network (DTN) concept, where the movement of vehicles and their message relaying service is used to enable network connectivity under unreliable conditions. To address the problem of intermittent connectivity, long-term message storage is combined with routing schemes that replicate messages at transfer opportunities...
Accurate searching in current structured P2P network is popular, but range query is very difficult and complex. In this paper, based on the Pastry, we propose a resources allocating mechanism for searching the objects among certain ranges in P2P network, and give the searching algorithm in detail. This mechanism does not need change the original P2P infrastructure, the algorithm is simple and easy...
In this paper, we present LiteView, an experimental toolkit for end-user diagnosis of communication path problems in sensor network systems. This toolkit provides an on-site, interactive environment that helps answering questions related to the instantaneous communication environments. For example, it allows users to identify broken links or asymmetric links, which are likely to become traffic bottlenecks...
The emergence of ubiquitous communication helps make safer and unobstructed street. Sensor detection is a valid technology to collect and process traffic data (vehicular speed, vehicle density, images from street) with the help of equipped sensors under the road or installed along the street. Vehicular sensor network (VSN), developed from wireless sensor network (WSN), is characterized by unlimited...
As the number of space elements increases, routing becomes an issue of great interest. The majority of routing schemes that have been proposed till now, employ a fairly static design and, only recently, more sophisticated protocols have been introduced. In this study, we evaluate some of the most prominent routing protocols for Delay-Tolerant Networks, Epidemic, PRoPHET and Contact Graph Routing,...
The paper introduces a secure DSR protocol, which is based on the principle of the sequence number increment and the scheme of the end-to-end acknowledgement. The OPNET simulation result shows that the secure routing design can resist the black-hole attack effectively.
This paper considers the problem of routing packets across a multi-hop wireless network while ensuring throughput optimality. One of the main challenges in the design of throughput optimal routing policies is identifying appropriate and universal Lyapunov functions with negative expected drift. The few well-known throughput optimal routing policies in the literature are constructed using simple quadratic...
This paper investigates conditions for an underdetermined linear system to have a unique nonnegative solution. A necessary condition is derived which requires the measurement matrix to have a row-span intersecting the positive orthant. For systems that satisfy this necessary condition, we provide equivalent characterizations for having a unique nonnegative solution. These conditions generalize existing...
Delay Tolerant Networks (DTN) are sparse ad hoc networks in which no contemporaneous path exists between any two nodes in the network most of the time. Due to non-availability of end-to-end paths, multicast protocols of traditional networks fail in DTN because they try to find connected multicast graph between source and destination nodes before forwarding data packets. Routing protocols proposed...
6LoWPAN is a low-power wireless personal area network and a technique to apply TCP/IP stack to sensor networks. By installing IPv6 stack to the sensor node, the sensor networks have interoperability with the external IPv6 network. To solve the 6LoWPAN's restrictions, IETF working group recently published problems, IPv6 header compression, and routing mechanism requirement documents through their study...
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