Platform for Multiagent Application Development Incorporating Accurate Communications Modeling

Multiagent systems are widely recognized as a method of choice for realization of distributed time-critical applications for the smart grid. However, no general solutions have been proposed for the difficult task of system development and validation, ready for deployment, which would fully account for the underlying communication network performance. We propose a novel platform designed for this purpose, which integrates a standard multiagent development framework [Java Agent Development (JADE)] and an industry standard communications network simulator (OPNET modeler).

It was realized through generic extensions of the JADE framework to provide discrete event scheduling capabilities, while the OPNET modeler was extended to provide a generic method of associating the network nodes with agents running in JADE. The adopted method adheres to the high-level architecture standard. Importantly, applications developed using this platform may be deployed on the target system without manual modifications. A distributed protection application is presented and the performance is analyzed with respect to candidate agent behaviors and communication scenarios, demonstrating that the feasibility of the application critically depends on the choices made during its design and implementation.

C22. Avionics Full-duplex switched Ethernet (AFDX): Modeling and simulation

This paper develops a comprehensive simulation model for Avionics Full-duplex switched Ethernet (AFDX) network based on OPNET platform. Accordingly, the performance of AFDX networks is analyzed. The effect of frame size, switching delay and changing frames transmission order on the AFDX network performance are investigated.

It is found that using faster switches and small frame size reduces the fixed part of the end to end delay. Also, it affects the variable part of end to end delay due to changing of delay in switches’ buffers and frames transmission order.

Modeling and Analyzing Duty-Cycling, Pipelined-Scheduling MACs for Linear Sensor Networks

Linear sensor networks (LSNs) have recently attracted increasing attention due to the vast requirements on the monitoring and surveillance of a structure or area with a linear topology. However, there is little work on the network modeling and analysis based on a duty-cycling MAC protocol for LSNs. In this paper, we model a duty-cycling MAC with a pipelinedscheduling feature for an LSN, where each node is responsible for monitoring a certain area and can generate packets according to its sensed results. Based on the model, we analyze the network performance in terms of the system throughput, active time ratio per cycle of each node, and packet delivery latency.

Through the extensive OPNET-based simulations, we validate the model and reveal the dependency of the network performance on various system parameters. Besides enabling the effective estimation of the protocol performance by using our model, we believe that our model and analysis could provide an insightful understanding on the behavior of a duty-cycling MAC protocol and aid its design and optimization for a multi-hop LSN.

Proportional Sharing in Distributed Dynamic Spectrum Access-Based Networks

Dynamic spectrum access (DSA) is a promising technology to alleviate the exhaustion of spectral resources. To realize DSA, new technologies that enable fast discovery of the unused spectrum along with efficient spectrum management must be developed. In this paper, we propose a novel scanning algorithm and access etiquette to provide secondary devices differentiated spectrum access in a fully distributed manner.

The proposed solution does not use any common control channel or require any a prior knowledge of primary devices’ usage pattern. More importantly, hardware limitation such as imperfect sensing or lack of strict synchronization between secondary devices are taken into account in our design. A mathematical model and an Opnet-based implementation are also developed to evaluate the performance of the proposed solution in DSA networks.

User-specific QoS aware scheduling and implementation in wireless systems

In this paper, we explore user-specific QoS requirements and associated schedulers that are very critical in optimizing the spectral allocation for wireless systems. Two user-specific QoS aware schedulers are proposed that considers the user-specific QoS requirements in the allocation of resources. Depending upon whether improving the MOS (Mean Opinion Score) or both the system capacity and the MOS is the goal, a MOS improvement scheduler or MOS-plus-capacity improvement scheduler is proposed for VoIP applications.

Detailed system implementation analysis based upon LTE system specification is performed, and it is shown that very modest modifications to current protocols are needed to support user-specific QoS aware scheduling. System simulations are performed for a set of VoIP users assigned specific QoS target levels in the OPNET Modeler for LTE systems. Simulation results show that appreciable MOS or/and system capacity improvement can be achieved if such user-specific QoS requirements are considered in the proposed user-specific QoS aware schedulers. Also, it is shown that the scheduling period of up to 1000 ms doesn’t significantly impair the system performance.

A new bandwidth-efficient multicast routing scheme for mobile Ad hoc Networks

This paper proposes an improved scheme based on Bandwidth-Efficient Multicast Routing (BEMR) for Mobile Ad Hoc Networks (MANET) to further reduce the control overhead whilst increasing the overall bandwidth efficiency. After carefully studying the original BEMR design, L· new approaches are proposed to enhance the BEMR performance One is in the tree set-up phase, while the other is for broken link recovery. Both the original BEMR and the new scheme (IBEMR) are simulated in self-developed OPNET-based platform.

The IBEMR scheme eventually builds a shared tree for this multicast group rather than a dedicate tree for a particular multicast sender generated by original BEMR. The result shows that for both route setup phase and route recovery phase, the IBEMR scheme provides better multicast efficiency with further reduced communication overhead.

Quality of service evaluation of VoIP over wireless networks

The Voice over IP (VoIP) service demands high priority over other services and applications. Some constrains are associated with this real-time service, such as delay and throughput which need to be addressed before delivering to the customer. The mobility in IP networks is a demand that facilitates IP applications and services, especially in wireless networks. This paper demonstrates the performance of Voice over IP (VoIP) in 802.11 wireless networks and elaborates on the evaluation of voice packet end-to-end delay and throughput. Employing literature reviews and an experimental model created on OPNET that is simulated to assess the quality of service (QoS) of VoIP in 802.11g legacy and 802.11e wireless network; shows the enhancement of 802.11 reflects as enhancement in the quality of the VoIP service.

The simulation results have indicated that the quality of VoIP service is influenced by the quality of the carrier which is IEEE 802.11 network. Therefore, the voice service over wireless network can be improved significantly by developing a quality of service policy that prioritizes the packet transmission based on the controlled access mechanisms. Eventually, the number of VoIP calls could be increased using the enhanced 802.11e standard rather than 802.11 standard.

Poster: A simulator for heterogeneous vehicular networks

We are aiming to better investigate heterogeneous vehicular networking technologies to overcome the shortcomings of using just a single wireless technology. Performance evaluation is usually done using simulation, for which we need integrated tools supporting WiFi, IEEE 802.11p, cellular technology, and mobility feedback.

The established vehicular networking simulators such as Veins, iTETRIS, or VSimRTI, however, currently have no support for such heterogeneous networking, in particular for Long Term Evolution (LTE). We present a new integrated simulation framework based on the popular and mature Veins framework named VeinsLTE. We present early results that clearly demonstrate the potential of this integrated approach.

A collaborative reputation approach to avoid misbehaving nodes in MANETs

Ad-hoc networks carry out routing and forwarding functions through available nodes. These nodes act as base stations and also are involved in route discovery and maintenance, forwarding traffic, and network management functions. Nodes expend most of their energy to forward packets to others without receiving any direct gain from doing so.

A misbehaving and greedy node only considers its own short-term utility, and it may not choose to participate within the network. A reputation approach (RAP) is proposed in this paper, based on the reputation model that is used to detect and isolate misbehaving nodes which do not cooperate in forwarding packets of other nodes. Promising results are found through extensive simulation using GloMoSim in identifying selfish nodes.

By-Passing Infected Areas in Wireless Sensor Networks Using BPR

Abnormalities in sensed data streams indicate the spread of malicious attacks, hardware failure and software corruption among the different nodes in a wireless sensor network. These factors of node infection can affect generated and incoming data streams resulting in high chances of inaccurate data, misleading packet translation, wrong decision making and severe communication disruption. This problem is detrimental to real-time applications having stringent quality-of-service (QoS) requirements. The sensed data from other uninfected regions might also get stuck in an infected region should no prior alternative arrangements are made. Although several existing methods (BOUNDHOLE and GAR) can be used to mitigate these issues, their performance is bounded by some limitations, mainly the high risk of falling into routing loops and involvement in unnecessary transmissions.

This paper provides a solution to by-pass the infected nodes dynamically using a twin rolling balls technique and also divert the packets that are trapped inside the identified area. The identification of infected nodes is done by adapting a Fuzzy data clustering approach which classifies the nodes based on the fraction of anomalous data that is detected in individual data streams. This information is then used in the proposed by-passed routing (BPR) which rotates two balls in two directions simultaneously: clockwise and counter-clockwise. The first node that hits any ball in any direction and is uninfected, is selected as the next hop. We are also concerned with the incoming packets or the packets-on-the-fly that may be affected when this problem occurs. Besides solving both of the problems in the existing methods, the proposed BPR technique has greatly improved the studied QoS parameters as shown by almost 40 percent increase in the overall performance.