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This paper analyzes the transmission efficiency of two kinds of communication technologies: summation frame and individual frame. The abstract models for these two communication technologies using linear topology, which is the most popular topology in industrial control field, are proposed in this paper. The simulation results based on the models show that summation frame has a significant performance...
Standardization bodies such as IEEE and 3GPP, as well as other interest groups, are in the process of defining and standardizing different functional subdivisions within mobile network base stations, primarily to reduce the data rate requirements imposed on the transport architecture by 4th and 5th generation mobile systems. Ethernet is considered the leading candidate for the transport architecture...
The future smart power grid will consist of an unlimited number of smart devices that communicate with control units to maintain the grid's sustainability, efficiency, and balancing. In order to build and verify such controllers over a large grid, a scalable simulation environment is needed. This paper presents an open source smart grid simulator (SGSim). The simulator is based on open source SystemC...
The VANET (Vehicular Ad hoc Network) is a collection of mobile nodes forming a temporary network on variable topology, operating without base station and without centralized administration. The characteristics of VANET network that distinguishes it from other ad hoc networks, such as high mobility and communication with the infrastructure to support security or comfort applications, have prompted...
Atomic multicast is a group communication primitive that allows disseminating messages to multiple distributed processes with strong ordering properties. As such, atomic multicast is a widely-employed tool to build large-scale systems, in particular when data is geo-distributed and/or replicated across multiple locations. However, all the most efficient atomic multicast algorithms suffer from a convoy...
To cope with data collision problem in consensus synchronization algorithm caused by utilizing pseudo-periodic broadcast method, this paper presents a novel gossip averaging based clock synchronization protocol, which combines the a synchronism of rumor communication and the robustness of neighbor averaging. We design a randomized link-activated based relative skew estimation strategy, which realizes...
Real-time applications in wireless sensor networks require that packets should reach to a sink within the time deadline. To satisfy the requirements, existing studies exploit nodes whose speed is higher than the desired delivery speed decided by the spatiotemporal approach. However, they fail real-time transmission in the area where there is no neighbor nodes which meet the requirements toward a sink...
Ns-3 is a widely used as a the network simulator of choice by researchers. It contains many well tested and high quality models of network protocols. However, the application layer models of ns-3 are very simplistic, and do not capture all aspects of real life applications. As a result, there is often a huge gap between the results of real experiments and the corresponding simulations. This problem...
The communication standard IEC 61850 which is defined for information exchange in smart grids, has been increasingly used for Substation Automation Systems (SAS). Current mainstream communication technologies such as switched Ethernet and TCP/IP have been adopted for the communications networking. However, with the growing amount of IEDs in one collision domain, a risk of violation of transmission...
Cloud computing has experienced enormous popularity and adoption in many areas, such as research, medical, web, and e-commerce. Providers, like Amazon, Google, Microsoft, and Yahoo have deployed their cloud services for use. Cloud computing pay-as-you-go model, on demand scaling, and low maintenance cost has attracted many users. The widespread adoption of cloud paradigm upshots various challenges...
In delay tolerant networks, the design of routing strategy is very challenging due to the characteristics of dynamic topology, long delay and intermittent connectivity. Most of existing routing strategies neglect the number limitation of intermediate nodes during forwarding messages. Owing to the small-world feature in delay tolerant networks, messages can reach destination nodes at most by five or...
EPA (Ethernet for Plant Automation) resolves the nondeterministic problem of Ethernet through sub-segment topology and deterministic scheduling mechanism. In this paper, the EPA scheduling mechanism is implemented by simulation tool. And the influence of EPA scheduling mechanism on network performance is shown in the simulation result. According to the study, the real-time performance of EPA periodic...
The DDS (Data Distribution Service) is real-time communication middleware used for a large-scale network system. For performance evaluation of the DDS, we developed a DDS simulator on QualNet. The performance measures obtained from the DDS simulator include discovery-completion time, end-to-end message-transfer delay, the number of data messages and the user-data processing time. The DDS simulator...
Under the opportunistic network environments, normal network protocols can hardly transfer data successfully and efficiently. In order to overcome this problem, many new routing algorithms have been raised pertinently. Thereinto, the Epidemic routing algorithm is a typical approach, which maintains least delay with a highest delivery ratio. However, it is a defective method for routing data as it...
In this work, we consider a space network time synchronization protocol which is based on time information exchanges similar to Network Time Protocol. Further, we analyze the performance of this time protocol due to relative motion with two spacecraft through using STK and Mat lab software jointly simulation. Regard the influencing factors such as relative distance between the two spacecraft, the...
This paper presents a new method for constructing a conflict graph for D2D communications in cellular systems, which is useful for efficient radio resource allocation for D2D links. The construction is an iterative process which includes a broadcast-and-acknowledgment protocol. The convergence and delay performance of the proposed constructing process is theoretically analyzed. Simulation results...
Wireless Sensor Network (WSN) is consisting of independent and distributed sensors to monitor physical or environmental conditions, such as temperature, sound, pressure, etc. Routing protocols represent an essential aspect of the performance of mobile wireless networks. This paper presents a comparative analysis between several routing algorithms and their impact on the performance of WSN. The performance...
Recent advances in physical layer communication techniques, enable receivers to decode multiple simultaneous transmissions. This technique is known as the multipacket reception (MPR). In this paper, we propose an enhancement to the IEEE 802.11ac EDCA protocol for channels supporting MPR for QoS provisioning. We show that in the case of MPR, in addition to CWmin, CWmax and AIFSN, we can use two more...
Network optimization based on utility maximization commonly refers to one-way flows. TCP flows comprise two oppositely directed flows, the forward data packet flow and the backward oriented flow of acknowledgement messages. This letter presents a network optimization model for two-way TCP flows, and the conditions to have multiple network equilibria. The simulation results of two-way FAST TCP flows...
We study the problem of designing downlink scheduling policy for wireless networks with both real-time and non-real-time flows. Most existing scheduling policies for these networks unfairly favor one type of flows. As a result, strategic clients may lie about their types of traffic in order to get more service from the base station. To counter these strategic behaviors, a scheduling policy should...
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