As we power through to the future, in-vehicle communications' reliance on speed is becoming a challenging predicament. This is mainly due to the ever-increasing number of electronic control units (ECUs), which will continue to drain network capacity, hence further increasing bandwidth demand. For a wired network, a tradeoff between bandwidth requirement, reliability, and cost-effectiveness has been our main motivation in developing a high-speed network architecture that is based on the integration of two time-triggered protocols namely; Time Triggered Ethernet (TT-E) and Time Triggered Controller Area Network (TT-CAN). Therefore, as a visible example of an Internet of Vehicles technology, we present a time triggered communication-based network architecture. The new architecture can provide scalable integration of advanced functionalities, while maintaining safety and high reliability. To comply with the bandwidth requirement, we consider high-speed TT-Ethernet as the main bus (i.e., backbone network) where sub-networks can use more cost-effective and lower bandwidth TT-CAN to communicate with other entities in the network via a gateway. The main challenge in the proposed network architecture has been to resolve interoperability between two entirely different time-triggered protocols, especially in terms of timing and synchronization. In this paper, we first explore the main key drivers of the proposed architecture, which are bandwidth, reliability, and timeliness. We then demonstrate the effectiveness of our gateway design in providing full interoperability between the two time-triggered protocols.

This paper focuses primarily on leveraging synchronized current/voltage amplitudes and phase angle measurements to foster new categories of applications, such as improving the effectiveness of grid protection and minimizing outage duration for distributed grid systems. The motivation for such an application arises from the fact that with the support of communication, synchronized measurements from multiple sites in a grid network can greatly enhance the accuracy and timeliness of identifying the source of instabilities. The paper first provides an overview of synchrophasor networks and then presents techniques for power quality assessment, including fault detection and protection. To achieve this we present a new synchrophasor data partitioning scheme that is based on the formation of a joint space and time observation vector. Since communication is an integral part of synchrophasor networks, the newly adopted wireless standard for machine-to-machine (M2M) communication, known as IEEE 802.11ah, has been investigated. The paper also presents a novel implementation of a hardware in the loop testbed for real-time performance evaluation. The purpose is to illustrate the use of both hardware and software tools to verify the performance of synchrophasor networks under more realistic environments. The testbed is a combination of grid network modeling, and an Emulab-based communication network. The combined grid and communication network is then used to assess power quality for fault detection and location using the IEEE 39-bus and 390-bus systems.

A major problem of the grid system is identifying the source of abnormal behaviors. It is particularly important to identify the areas in which the grid system suffers from power deficiencies due to fault or voltage instability. Phasor Measurement Units (PMUs) are capable of measuring current and voltage amplitudes and phase angles, which can then be effectively used to monitor the power quality. This would require the support of a communication network to detect regions in the grid that may suffer from voltage instability. In this paper we present a distributed mapping technique that is based on a hierarchical network structure to identify the proximity of the grid instability for any possible remedial control action at the local level. For voltage monitoring, we also develop an average standard deviation measurement technique to access the power quality. We use the IEEE 34 bus grid distribution model and the IEEE 39 bus transmission model to assess the performance of the proposed techniques.

Linear dispersion codes (LDC) can support arbitrary configurations of transmit and receive antennas in multi-input multi-output (MIMO) systems. In this paper, we investigate two transmit diversity applications of LDC for orthogonal frequency division multiplexing (OFDM) systems in order to achieve space-time/frequency (ST/SF) diversity gains when transmitting over time-/frequency-selective fading channels. LDC-aided ST/SF-OFDM is flexible in configuring various numbers of transmit antennas and time-slots or frequency-tones. Our results show that the ST-OFDM scheme is sensitive to exploiting diversity gains, subject to the impact of varying channel Doppler spreads; while the performance of SF-OFDM is mainly subject to delay spread. Particularly, when the transmitter employs more than two antennas, the LDC-aided ST/SF-OFDM outperforms the orthogonal block codes (e.g. Tarokh's codes) aided ST/SF-OFDM, when communicating over higher Doppler/delay spread.

There has been a growing interest in the deployment of Phasor Measurement Units (PMUs) in a Distributed Generation (DG) grid system. A major obstacle is the lack of a communication network infrastructure that can support phasor measurements for distribution area monitoring as well as providing sensing capabilities for protection against undesirable grid dynamics. In the absence of such a network, the most cost-effective solution would be to consider a wireless network to support centralized control for situational awareness in a DG environment. Therefore, the main objective in this paper is to design and implement a synchrophasor network testbed using Wireless LAN (WLAN) technology. Based on a hierarchical network architecture, we propose an efficient method to reduce the synchrophasor data bandwidth, as well as provide capabilities for control and management at each hierarchical level. This testbed is then used to evaluate different network configurations under various test conditions.

In this paper, a greedy backpressure routing protocol is proposed for multigate mesh networks. This protocol evaluates the greedy backpressure metric (GBM) value of mesh points and routes packets in the direction of the steepest gradient. The GBM value is calculated using a combination of traffic load and the mesh point's hop count to the closest gateway. The proposed routing algorithm can realize the effect of traffic load from all the nodes along the path to each gateway by iteratively updating information from neighbors through periodic beacon exchange. The consideration of incorporating traffic load helps to route packets around congested area. The results indicate that the greedy backpressure multigate mesh routing is capable of achieving significant improvement in the network reliability, latency, and throughput performance.

Wireless mesh/sensor networks offer various unique features such as self-configuration, ease of installation, scalability, and self-healing, which make them very attractive for deployment in various smart grid domains, such as Home Area Networks (HAN), Neighborhood Area Networks (NAN), and substation/plant-generation local area networks for real-time monitoring and control. Their main drawback is that they are more exposed to cyber-attack as data packets have to be relayed on a hop-by-hop basis. This paper presents a dynamically updating key distribution strategy, together with a message protection scheme in support of 4-way handshaking. For the 4-way handshaking, we propose a hash based encryption scheme to secure the unprotected message exchanges during the handshaking process. This is aimed at improving the resiliency of the network in the situation where an intruder carries a denial of service attack. We then evaluate the security of the proposed scheme against cyber-attack, as well as network performance in terms of delay and overhead.

One of the most important issues in Smart Grid is to provide consumers with the knowledge of their energy usage, as well as allowing the utility to monitor and control the electric system components with real time status. This would require the design of a network architecture that is capable of providing secure and reliable two-way communication from meters to other Smart Grid domains. While networking technologies and systems have been greatly enhanced, in wireless communication environments the smart grid faces new challenges in terms of reliability. In this paper we are mainly concerned with assessing the performance of wireless mesh networks for the last mile communication. We consider a tree-based mesh routing scheme based on a multigate mesh network architecture. The multigate mesh routing scheme is based on a flexible mesh network architecture that expands on the hybrid tree routing of the IEEE 802.11s. The network is specifically designed to operate in a multi gateway structure in order to meet the smart grid requirements in terms of reliability, self-healing, and throughput performance. To further exploit the multigate network structure, a timer-based multipath routing diversity scheme is proposed in order to enhance the network reliability. The network is then used to measure the performance in terms of throughput and reliability.

It is envisioned that one of the most important issues in smart grid will be to design a network architecture that is capable of providing secure and reliable two-way communication from meters to other Smart Grid domains. While networking technologies and systems have been greatly enhanced, in wireless communication environments the smart grid faces new challenges in terms of reliability and efficiency. In this paper we present a multigate mesh network architecture to handle real-time traffic for the last mile communication. The paper consists of three parts; multigate routing, real-time traffic scheduling, and multichannel (MC) aided wireless mesh routing. The multigate routing is based on a flexible mesh network architecture that expands on the hybrid tree routing of the IEEE 802.11s. The network is specifically designed to operate in a multi gateway structure in order to meet the smart grid requirements in terms of reliability, self-healing, and throughput performance. This includes developing a timer-based multiple-path diversity scheme that takes advantage of the multi gateway network structure. With respect to packet scheduling, we introduce a novel and efficient scheme that is capable of balancing the traffic load among multiple gateways. The proposed scheme, which is based on the backpressure concept due to its simplicity, is suitable for practical implementation. We also present an MC aided wireless mesh routing protocol which is specifically designed for multigate smart grid networks. The results indicate that a combination of multipath routing and the backpressure-based packet-scheduling scheme can show a significant improvement in the network reliability, latency, and throughput performance. We also show an improvement in the order of magnitude can be achieved via the proposed multichannel aided routing protocol.

In this paper, we present a systematic design structure for high-density ad hoc networks aimed at achieving full cooperative diversity, based on which the PHY, MAC and Network layers of the system are specifically tailored. For the latter in particular, we present a cooperative routing protocol that is capable of exploiting full transmit diversity in adhoc networks. Simulation results are provided to demonstrate the substantial performance gain in terms of increased packet delivery reliability over high-throughput scenarios and reduced system delay, achieved by the cooperative diversity attained using a virtual MIMO system architecture.

Multipath routing can be effectively used to maximize the utilization of network resources for real-time traffic. In mobile ad-hoc network environments, this approach can suffer from co-channel interference due to the simultaneous transmission of packets via multiple routes. In this paper, by exploiting the directionality of directional antennas, a Directional Dynamic Source Routing (DDSR)-based Multipath routing protocol is proposed for mobile wireless ad hoc networks. Three metrics are considered in the route discovery process in order to select the best multiple routes. These are hop count, beam overlaps, and the number of joint nodes between the different routes. The proposed directional routing protocol has shown to be capable of minimizing inter-path and intra-path interference, hence significantly improving the system throughput performance for simultaneous transmission of multimedia information over multiple routes.

A directional routing approach for multihop ad-hoc networks, is presented which has been applied to two on-demand routing protocols: namely dynamic source routing (DSR) and ad-hoc on-demand distance vector routing (AODV). Both DSR-based and AODV-based directional routing protocols are designed to balance the trade-off between co-channel interferences from nodes hops away and the total power consumed by all the nodes. In order to select the best route, three metrics are considered in the route discovery process. They consist of hop count, power budget and overlaps between adjacent beams. By exploiting the direction of directional antennas, both routing protocols are capable of reducing overlaps between beams of the nodes along the route, thus eliminating interference. Arbitrary networks and random networks are considered in the simulations. The results show considerable performance gains for transmission of real-time traffic over ad hoc networks.

In this paper, a Dynamic Source Routing (DSR)- based directional routing protocol is invoked for wireless ad hoc networks using directional antennas. This is designed to balance the trade-off between co-channel interferences from nodes hops away, and the total power consumed by all the nodes. Three metrics are considered in the route discovery process in order to select the best route: hop count, power budget and overlaps between adjacent beams. By exploiting the directionality of directional antennas, the proposed DSR-based directional routing protocol is capable of reducing the overlaps between beams of the nodes along the route, hence eliminating the interference. Arbitrary networks and random networks are considered in our simulations. The results show considerable performance gains for transmission of real-time traffic over ad hoc networks.