Search results for "Computer network"
showing 10 items of 1634 documents
Review of machine to machine communication in smart grid
2016
Machine to machine communication (M2M) is a communication architecture that enables heterogeneous devices to interact with each other without human intervention. Smart Grid (SG) is one of the many applications areas in the M2M communication. Smart Grid demands advanced communication infrastructure for two-way communications between devices deployed at various locations in energy generation, transmission, distribution and consumption. The billions of electronic devices connected to the Smart Grid pose a big challenge to grid communication. Therefore, a feasible solution to efficient M2M has to overcome challenges of energy efficiency of connected devices, interoperability, coverage area, int…
UbiRoad: Semantic Middleware for Context-Aware Smart Road Environments
2010
A smart road environment is such a traffic environment that is equipped with all necessary facilities to enable seamless mobile service provisioning to the users. However, advanced sensors and network architectures deployed within the traffic environment are insufficient to make mobile service provisioning autonomous and proactive, thus minimizing drivers’ distraction during their presence in the environment. For that, an Intelligent Transportation System, which is operating on top of numerous sensor and access networks and governing the process of mobile services provisioning to the users in self-managed and proactive way, must be deployed. Specifically, such system should provide solution…
Advances in vehicle routing and logistics optimization
2019
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A multi-agent system for obtaining dynamic origin/destination matrices on intelligent road networks
2012
Dynamic Origin/Destination matrices are one of the most important parameters for efficient and effective transportation system management. These matrices describe the vehicle flow between different points inside a region of interest for a given period of time. Usually, dynamic O/D matrices are estimated from link traffic counts, home interview and/or license plate surveys. Unfortunately, estimation methods take O/D flows as time invariant for a certain number of intervals of time, which cannot be suitable for some traffic applications. However, the advent of information and communication technologies (e.g., vehicle-to-infrastructure dedicated short range communications — V2I) to the transpo…
Reliable Underlay Device-to-Device Communications on Multiple Channels
2019
Device-to-device (D2D) communications provide a substantial increase in spectrum usage and efficiency by allowing nearby users to communicate directly without passing their packets through the base station (BS). In previous works, proper channel assignment and power allocation algorithms for sharing of channels between cellular users and D2D pairs, usually require exact knowledge of the channel-state-information (CSI). However, due to the non-stationary wireless environment and the need to limit the communication and computation overheads, obtaining perfect CSI in the D2D communication scenario is generally not possible. In this work, we propose a joint channel assignment and power allocati…
Uplink DPCCH Gating of Inactive UEs in Continuous Packet Connectivity Mode for HSUPA
2007
In order to further improve the packet performance in the UMTS FDD system, uplink dedicated physical control channel (DPCCH) gating as a scheme is proposed in 3GPP under the work item "continuous connectivity for packet data users". In this paper, the uplink DPCCH gating concept is described and analyzed on both a qualitative and a quantitative level. And the system performance of different gating patterns used in the scheme was investigated by analytical prediction and system level simulations with different channel profiles. As shown, the selection of the gating pattern has a significant influence on the system performance, which is correlated with the uplink data transmission activity an…
Cooperative or non-cooperative transmission in synchronous DC WSNs: A DTMC-based approach
2017
Cooperative transmission (CT) enables balanced energy consumption among sensor nodes and mitigates the energy hole problem in wireless sensor networks (WSNs). In typical CT enabled medium access control (MAC) protocols, a source node decides to trigger CT or not based on a residual energy comparison between itself and its relay node. In this paper, we propose a receiver initiated CT MAC protocol, in which the receiving node makes the decision on initiating CT or not based on a tradeoff between performing CT and non-CT. In this way, nodes can avoid idle listening and achieve an extended lifetime. A discrete-time Markov chain (DTMC) model is developed to analyze the performance of CT associat…
Maximum Lifetime of the Wireless Sensor Network and the Gossip Problem
2018
In the gossip problem each node of the graph G possesses a unique piece of information - the gossip message. A sequence of one-way or two-way communications between pair of nodes is made to spread the messages so that any node of the graph knows all the gossips. The question is, what is the minimum number of calls between pairs of nodes needed to exchange all gossip messages? The solution to the two-way communication gossip problem is that \(2N-4\) calls (\(N\ge 4\)) suffice if and only if the graph contains a four cycle subgraph. For one-way communication problem the classical results states that in a strongly connected graph \(2N-2\) calls (\(N\ge 4\)) suffice. In this paper we consider t…
P2PStudio - Monitoring, Controlling and Visualization Tool for Peer-to-Peer Networks Research
2006
Peer-to-Peer Studio has been developed as a monitoring, controlling and visualization tool for peer-to-peer networks. It uses a centralized architecture to gather events from a peer-to-peer network and can be used to visualize network topology and to send different commands to individual peer-to-peer nodes. The tool has been used with Chedar Peer-to-Peer network to study the behavior of different peer-to-peer resource discovery and topology management algorithms and for visualizing the results of NeuroSearch resource discovery algorithm produced by the Peer-to-Peer Realm network simulator. This paper presents the features, the architecture and the protocols of Peer-to-Peer Studio and the ex…
Efficiency analysis of burst transmissions with block ACK in contention-based 802.11e WLANs
2005
The channel utilization efficiency of the standard 802.11 networks is severely compromised when high data transmission rates are employed, since physical layer headers and control frames are transmitted at low rate, thus wasting more channel time, proportionally. The extensions defined in the emerging 802.11e for quality-of-service (QoS) provisioning include some new mechanisms developed in order to improve the efficiency. Those include data transmission bursting (referred to as TXOP operation) and acknowledgment aggregation (referred to as block ACK). These two features allow it to offer new data transmission services, in which the data delivery and acknowledgment unit is not a single fram…