Gowdemy Rajalingham

Quality of service differentiation for smart grid neighbor area networks through multiple RPL instances

The Smart Grid (SG) optimizes the existing power grid with a reliable and secure SG Communications Network. For uplink data traffic, the Neighbor Area Network (NAN) segments size and converge-cast traffic can be addressed with the Routing Protocol for Low Power and Lossy Networks (RPL). Additionally, a broad range of SG applications, such as monitoring, control and automation applications, have been proposed in order to achieve the anticipated SG goals. These applications, each possessing different Quality of Service (QoS) requirements such as bandwidth, latency, reliability and security, will require traffic prioritization and differentiation. Generally, QoS is addressed through queue scheduling mechanisms or prioritized channel access at the Medium Access Control (MAC) layer. In this paper, extensions to the standard MAC level QoS techniques are explored with an emphasis on network layer QoS mechanisms. Specifically, the effectiveness of multiple instances of the RPL network graph, built upon differing objective functions, for QoS differentiation is investigated. To that effect, three variants of RPL, standard RPL, multi-instance RPL (RPL-M) and multi-instance RPL with prioritized channel backoffs (RPL-M+) along with two distinct traffic classes have been examined as data traffic rate and composition was varied.

Evaluation of an efficient Smart Grid communication system at the neighbor area level

The successful implementation of Smart Grid (SG) requires an efficient communication infrastructure that is cost-effective, scalable and fault-tolerant. This paper aims to study and develop relevant networking techniques for an efficient and reliable SG Communication Network (SGCN). In particular, we propose a viable communication architecture for the interconnection of different radio access technologies along the separate segments of the SGCN. Specifically, WiFi mesh network at the Neighbor Area Network (NAN) level with LTE at the Wide Area Network (WAN) level. Based on this architecture, the performance, transmission latency and Packet Delivery Ratio (PDR), of geographic routing in the NAN segment is considered. Specifically, the scaling of system performance when per-smart-meter data rate, channel shadowing level and the number of smart meters per collector increases is investigated. The results presented in this study can then serve as important guidelines for the design and development of relevant communication infrastructures for SGs.

Performance and applicability of candidate routing protocols for smart grid's wireless mesh neighbor area networks

Neighbor area network (NAN) is one of the most important segments of smart grid communications network (SGCN) since it is responsible for the information exchanges between the utility and a large number of smart meters (SMs) in order to enable various important smart grid (SG) applications. Greedy perimeter stateless routing (GPSR) and the routing protocol for low-power and lossy networks (RPL) have been considered as the most promising layer-3 protocols for wireless mesh NANs. This paper compares the system performance and investigates the applicability of these two protocols in practical NAN scenarios. Specifically, transmission reliability, latency and routing path details of GPSR and RPL are studied by extensive simulations. The advantages and disadvantages of each protocol with respect to the characteristics and required features of NAN are discussed in details. The effects of wireless channel characteristics and network offered load levels are also investigated.

Attainable throughput, delay and scalability for geographic routing on Smart Grid neighbor area networks

Challenges of the existing power grid demand the integration of information and communication technologies into the next-generation electric grid, namely the Smart Grid (SG). This paper focuses on the critical communications segment corresponding to the consumer-premise, the Neighbor Area Network (NAN). For this segment, Greedy Perimeter Stateless Routing (GPSR) protocol is considered for its low complexity and high scalability. In order to provide guidelines for SG communications system designers and network engineers, the performance of GPSR in terms of throughput, latency and scalability is investigated with parametric sweeps of transmission range, data rate and the number of Smart Meters (SMs) per Data Aggregation Point (DAP). The simulation results show that network throughput of hundreds of times the rate required for basic SG applications (e.g., meter reading, service switch, ...) can be achieved while the end-to-end delay can always be maintained below 100 ms. However, the converge-cast nature of the uplink traffic severely limits the SM-to-DAP ratio. Thus, with GPSR at the NAN level, emerging SG applications such as smart metering, real-time pricing, demand response, etc., can be supported.

Wireless Communications Networks for the Smart Grid

This brief presents a comprehensive review of the network architecture and communication technologies of the smart grid communication network (SGCN). It then studies the strengths, weaknesses and applications of two promising wireless mesh routing protocols that could be used to implement the SGCN. Packet transmission reliability, latency and robustness of these two protocols are evaluated and compared by simulations in various practical SGCN scenarios. Finally, technical challenges and open research opportunities of the SGCN are addressed. Wireless Communications Networks for Smart Grid provides communication network architects and engineers with valuable proven suggestions to successfully implement the SGCN. Advanced-level students studying computer science or electrical engineering will also find the content helpful.

Random Linear Network Coding for converge-cast Smart Grid wireless networks

The power electric grid is undergoing a paradigm shift with the inclusion of information and communication technologies that allow for two-way flow of information, automation and distributed intelligence. A reliable and secure Smart-Grid Communications Network (SGCN), is necessary to achieve the SG goals. In particular, the SG Neighbor Area Network (NAN) poses a communications challenge due to the bottlenecks associated with the converge-cast nature of uplink traffic. This can potentially be addressed through network coding. Therefore, this paper aims to determine the feasibility of Random Linear Network Coding (RLNC) at the SG NAN level. Specifically, RLNC is considered in converge-cast scenarios while both network size and link reliability are varied. This preliminary study suggests that inter-session RLNC does achieve throughput enhancements but at the cost of higher network load. Additionally, performance drops sharply with low link reliabilities due to the lack of partial decoding. Therefore, for large converge-cast networks, as in the case of the SG NAN, network coding that allows for partial decoding operations should be more beneficial.

Performance and applicability of geographic-based routing in smart grid's neighbor area networks

Neighbor area network (NAN) is one of the most important segments of smart grid communications network (SGCN). This paper studies the performance of geographic-based greedy perimeter stateless routing (GPSR) in the NAN scenario and investigates the feasibility of this routing protocol in supporting S G applications. Specifically, packet transmission delay and reliability of GPSR in an IEEE 802.15.4-based wireless mesh NAN with practical system parameters are measured by simulations. The results show that, at the basic data rate, the delay can always be maintained below 70 ms (95% quartile) while packet delivery ratio is higher than 90%. This means that the simulated NAN can support a great number of S G applications including smart metering, real-time pricing, demand response, etc. However, due to that fact that more advanced applications that require information exchange at higher rates and more stringent delays are emerging in SG, the performance of GPSR in NAN scenarios using various radio technologies with higher offered loads and/or larger network scales needs to be studied.

Robustness of the routing protocol for low-power and lossy networks (RPL) in smart grid's neighbor-area networks

Neighbor-area network (NAN), also known as smart meter communication network, is one of the most important constitutive segments of smart grid communication network. Since almost all smart meters are deployed in hash outdoor environment, they could fail or wireless links between them could be fluctuating over time. These dynamics could hinder the network connectivity and degrade the reliability of data communications. However, the robustness of NANs in the case of network element failures has not received sufficient attention in existing work. This paper therefore proposes a cross-layer scheme that adaptively switches preferred parent nodes in order to help the routing protocol for low-power and lossy networks (RPL), the state-of-the-art implementation of self-organizing routing class, quickly deflect network traffic from points of failures in the NAN scenario. Operation and performance of the proposed scheme in IEEE 802.11-based wireless mesh NANs are studied by simulations.

A distributed and adaptive routing protocol designed for wireless sensor networks deployed in clinical environments

The effects of electromagnetic interference (EMI) on operations of sensitive medical devices have been recognized as a critical concern related to safety in hospitals and healthcare institutions. This paper proposes an adaptive and distributed routing protocol that attempts to reduce the EMI introduced by a medical wireless sensor network (MWSN). The proposed algorithm, namely EMI-aware routing protocol (EMIR), assigns to each node a potential value which is dynamically calculated in such a way that network traffic tends to be deflected from nodes that are radiating high EMI and/or locating far away from gateways. Experiments in a real-life IEEE 802.15.4-based WSN implemented with the EMIR demonstrate that, compared to the shortest path routing, the proposed algorithm can significantly suppress the level of the EMI in the surrounding area where the WSN is deployed. Besides, the EMIR is scalable to the network size because it only requires one-hop neighbor information.

Smart Grid Communications Network (SGCN)

This chapter provides a top-level system description as well as technical details for the SGCN so as to help readers grasp system and network requirements and challenges when designing and implementing the SGCN. Specifically, this chapter elaborates on the overall architecture of the SGCN by decomposing it into three representative network segments. For each segment, details regarding required communication delay, bandwidth, network coverage and potential applications are addressed. Since inter-operability is one of the most vital concerns in the SGSN, this chapter then gives an overview on the standards for the SGCN developed by various organizations such as the Institute of Electrical and Electronics Engineers (IEEE) and the National Institute and Technology (NIST). Finally, this chapter discusses QoS attributes and requirements of the various elements in the SGCN.