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This paper addresses the problem of optimal gateways selection and route selection to Internet in backbone wireless mesh networks (WMNs) where each mesh router (MR) is equipped with multiple radio interfaces and a subset of nodes serve as gateways to Internet. Several schemes have been proposed to route packets in WMNs or to select appropriate gateways to connect clients to Internet. However, most...
Cognitive radio ad hoc networks (CRAHNs) solve the problem of spectrum utilization when the licensed or primary user (PU) activity changes over time. This affects not only the spectrum availability, but also the network topology, making the analysis of scaling laws very challenging. Currently, the effect of PU activity on the network scaling laws has not been theoretically analyzed, to the best of...
We consider the realtime services over on-demand routing protocols in ad hoc networks, where infrastructure does not exist and the network topology is highly dynamic and time-varying due to node mobilities. To reduce the end-to-end delay, we have proposed two efficient routing protocols: MSR (Multipath Source Routing) and RSR (Redundant Source Routing) in our previous work. Simulations have shown...
In recent years the research on Vehicular Ad Hoc Network (VANET) has been paid much attention due to the development of wireless network becoming mature, people think highly of traffic safety issue, the popularity of Global Positioning System (GPS), promising applications of VANET being exploited. However, VANET has the essential property of rapid change of large scale network topology. Besides, the...
In this paper, we discuss the physical arrangement of wireless nodes to form topologies suitable for the implementation of Network Coding. Boundaries for the most favorable placement of the nodes to form Bow-Tie and Butterfly network coding suitable topologies, are mathematically calculated with a log-distance model. Simulations in OPNET Modeler were conducted with these node positions in mind, in...
In-network aggregation has become a promising technique for improving the energy efficiency of wireless sensor networks. Aggregating data at various nodes in the network results in a reduction in the amount of bits transmitted over the network, and hence, saves energy. In this paper, we focus on another important aspect of aggregation, i.e., delay performance. In conjunction with link scheduling,...
In this paper dissemination algorithms to transfer warning messages from the originator node to the remaining recipient nodes within a specified geographic area are considered. Analytical methods are developed to obtain time-probabilistic characteristics of these algorithms for linear network topology and fixed success probability of one-hop transmission. The applicability of the obtained results...
We consider CSMA policies for multihop wireless networks. CSMA policies are simple policies that can be easily implemented in a distributed manner. However, the delay performance of CSMA policies can be very poor as the delay can grow exponentially in the network size. As a result, CSMA policies are not practical for delay-sensitive traffic even for mid-sized networks. In this paper, we consider a...
Reasonable and effective communication simulation model is an important basic constitutes of joint operations simulation. The communication delay computation of the communication model is the prerequisite of high-level operational simulation. Combing with the high-level, complex communication network types and structure characteristics of joint operations simulation system, the paper put forward the...
When supporting both voice and TCP in a wireless multihop network, there are two conflicting goals: to protect the VoIP traffic, and to completely utilize the remaining capacity for TCP. We investigate the interaction between these two popular categories of traffic and find that conventional solution approaches, such as enhanced TCP variants, priority queues, bandwidth limitation, and traffic shaping...
We study the problem of maximizing the aggregated revenue in sensor networks with deadline constraints. Our model is that of a sensor network that is arranged in the form of a tree topology, where the root corresponds to the sink node, and the rest of the network detects an event and transmits data to the sink over one or more hops. We assume a time-slotted synchronized system and a node-exclusive...
Wireless ad hoc networks using omni-directional antennas do not scale well due to interference between nearby nodes. Maintaining the QoS of the communications in this type of network is a difficult task. Using multiple narrow beam directional antennas alleviates this problem at the expense of connectivity. Multi-beam smart antennas allow the network topology to be adjusted dynamically by adjusting...
Interference in wireless sensor networks (WSNs) not only causes packet loss and delay, but also leads to excessive energy consumption. It is necessary to alleviate interference in order to improve transmission and energy efficiencies. To achieve this objective, an interference-aware cross-layer design, called interference-aware routing (IAR) protocol, is proposed. Unlike existing contention-based...
Network topology does not change dynamically in wireless mesh networks. Most of the end-to-end traffic flows are between mesh nodes and gateways. A tree-base routing algorithm is suitable for such network architecture. When using multichannel and multi-interface, routing algorithm and channel assignment is codependent. They should be combined together to fully exploit the network capacity. We propose...
In this paper, we consider the important aspect of quality of service (QoS) in wireless mesh networks, focusing on packet delays and packet drops. We observe that the options of solely focusing on throughput, and of only depending on the QoS type characterization by the application level protocol is not sufficient. We propose the use of multiple queues to hold the packets based on their QoS requirement...
The base station (BS) deployment planning is become more complex for the next-generation wireless networks, which is an architecture with multi-tier topology. The multiple coexist networks are deployed to serve different kinds of mobile users that their traffic requirements and moving speeds are different. Thus, in this paper, we discuss how to deploy the heterogenous BSs that support different service...
Efforts to improve the capacity of multi-channel, multi-interface wireless mesh networks have mainly focused on mitigating channel interference and balancing traffic loads. In a limited number of channels and interfaces, this approach cannot help encountering the network overload and traffic saturation, as network traffic increases. It will be serious, especially at intersecting nodes such as the...
In this paper we introduce a joint cross layer routing and resource allocation algorithm for multi radio wireless mesh networks. We focus on wireless mesh networks with stationary nodes. The resource allocation part assigns frequency bands to links such that the interference between those links is minimized while maximizing the coherence time of each link. The routing part selects the paths with the...
The performance of multi-channel multi-radio (MC-MR) wireless mesh networks (WMNs) can be improved significantly with the increase in number of channels and radios. Despite the availability of multiple channels in several of the current wireless standards, only a few of them are non- overlapping and many channels are partially overlapped. In this paper, we formulate the joint channel assignment and...
This paper examines the performance of segregate networks with single and multiple channels. It compares the simulation results to the location-aware channel assignment protocol named GRID. The term segregated means that the network is divided into smaller domains and each one operates on different radios. Each node is assigned a predefined pool of radios, per segregate. The results show that the...
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