No abstract

No abstract

In order to support various innovative demand response programs, smart grid needs a wireless communication network with quality-of-service (QoS) support. This paper studies the issue of providing QoS in terms of packet delay, packet error probability, and outage probability to a large number of sensors and smart meters in a neighborhood area network of a densely populated urban area. We assume the network is based on the IEEE 802.15.4g Standard. Given that bandwidth is limited, we propose to divide smart meters into groups and each group will take a turn to access a shared wireless channel in a time-division-multiplexing manner. Within each allocated time duration, a group of smart meters will compete for channel access using a simple slotted Aloha protocol. We have developed an analytical model to quantify the QoS metrics. Through the analytical model, we can determine the minimum concentrator density that is required to support a given smart meter density. We have verified the analytical model through simulations. The results show that we need less than ten concentrators per km 2 to support a node density of 500 units per km 2 , while making sure that packet delay does not exceed 1.0 s, packet error probability is below 0.005 and outage probability is lower than 0.01.Index Terms-Concentrator density, neighborhood area network (NAN), quality-of-service (QoS), sensor, smart grid, smart meter.

No abstract

This paper details a novel approach of developing a low-cost and high speed maritime ship-to-ship/shore mesh network to complement or replace satellite communications in narrow water channels or traffic lanes close to shorelines. To design the system, we gathered requirements from typical users of the system. We then carried out preliminary studies such as radio channel propagation over sea water, ship movement patterns, ship rocking and its effect on radio transmission and network connectivity to determine the feasibility of using a mesh network for maritime networks. We present the architecture and detail some of our routing and scheduling design considerations that address the unique challenges of the maritime environment and provide us with framework for providing fair and equal opportunity access to users.

No abstract

Abstract-Upon the occurrence of a phenomenon of interest in a wireless sensor network, multiple sensors may be activated, leading to data implosion and redundancy. Data aggregation and/or fusion techniques exploit spatio-temporal correlation among sensory data to reduce traffic load and mitigate congestion. However, this is often at the expense of loss in Information Quality (IQ) of data that is collected at the fusion center.In this work, we address the problem of finding the leastcost routing tree that satisfies a given IQ constraint. We note that the optimal least-cost routing solution is a variation of the classical NP-hard Steiner tree problem in graphs, which incurs high overheads as it requires knowledge of the entire network topology and individual IQ contributions of each activated sensor node. We tackle these issues by proposing: (i) a topology-aware histogram-based aggregation structure that encapsulates the cost of including the IQ contribution of each activated node in a compact and efficient way; and (ii) a greedy heuristic to approximate and prune a least-cost aggregation routing path. We show that the performance of our IQ-aware routing protocol is: (i) bounded by a distance-based aggregation tree that collects data from all the activated nodes; and (ii) comparable to another IQ-aware routing protocol that uses an exhaustive brute-force search to approximate and prune the least-cost aggregation tree.

This paper gives an overview of the TRITON project that aims to develop a high-speed maritime ship-to-ship/shore mesh network. We present the general architecture of the TRITON system and detail our preliminary studies and findings that will help us determine the feasibility of using ships and shoreline base stations to form a mesh network.