The approach and primary achievements of the Survivable, Adaptive Networks (SURAN) Program are summarized. The purpose of the program is to research and develop network technology capable of supporting communication between computers and their users on the modern battlefield. Accomplishments include a comprehensive set of adaptive, robust, and secure network algorithms, an automated laboratory testbed, and an experimental, low-cost, packet radio network that integrates and demonstrates SURAN technology. Open issues for survivable network research are briefly discussed. >

Accomplishments of the DARPA SURAN Program

The dynamic and lossy nature of wireless communication poses major challenges to reliable, self-organizing multihop networks. Non-ideal link characteristics are especially problematic with the primitive, low-power radio transceivers found in sensor networks and raise new issues that routing protocols must address. We redefine the basic notion of wireless connectivity in terms of probabilistic links, and demonstrate that link statistics can be captured dynamically through an efficient yet adaptive link estimator. This probabilistic notion of connectivity changes the usual concept of a neighbor and introduces new problems with neighborhood management: the neighbor table on a sensor node is of fixed size and cannot always be used to gather link statistics about all neighbors, yet the process of selecting the most competitive neighbors requires a comparison with the link statistics of those neighbors that are not in the table. Together, link estimation and neighborhood management build a probabilistic connectivity graph which can be exploited by a routing algorithm to increase reliability. Together, these three processes constitute our holistic approach to routing. We study and evaluate link estimation, neighborhood table management, and reliable routing protocol techniques, focusing on the many-to-one, periodic data collection workload commonly found in sensor network applications today. Our final system uses a variant of an exponentially weighted moving average estimator, frequency based table management, and minimum transmission cost-based routing. Our analysis ranges from large-scale, high-level simulations to in-depth empirical experiments and emphasizes the intricate interactions between the routing topology and the underlying connectivity graph, which underscores the need for a whole-system approach to the problem of routing in wireless sensor networks.

A holistic approach to multihop routing in sensor networks

The unique features of a multisatellite network, which distinguish it from ordinary terrestrial networks, are the large propagation delay on the links, the constant changes in the network topology, and additional constraints such as limitation on power consumption. It is noted that ordinary protocols, which are designed to operate in stable, benign environments, will perform poorly under the dynamic conditions of multisatellite network. The author analyzes the limitations to existing protocols and describes protocols, such as routing, topology control, and reliable transport, that are suitable for multisatellite networks. >

Protocols for multi-satellite networks

A new point process for station location in multihop radio network modeling is introduced. This inhibition process, due to Matern (1960), provides a random placement of stations while maintaining a minimal distance between any two stations. Such minimal spacing can arise for applied reasons. A comparison of the characteristics of the inhibition process and the commonly used Poisson process is provided. The proposed model seems to have benefits in terms of intuition concerning the dependence of station locations. However, its chief use will probably be in network simulation. It is not as analytically tractable as the Poisson spatial point process. >

A new spatial point process for multihop radio network modeling

Logistics has experienced a long time of developments and improvements based on the advanced vehicle technologies, transportation systems, traffic network extension and logistics processes. In the last decades, the complexity has increased significantly and this has created complex logistics networks over multiple continents. Because of the close cooperation, these logistics networks are highly dependent on each other in sharing and processing the logistics information. Every customer has many suppliers and vice versa. The conventional centralized control continues but reaches some limitations such as the different distribution of suppliers, the complexity and flexibility of processing orders or the dynamics of the logistic objects. In order to overcome these disadvantages, the paradigm of autonomous logistics is proposed and promises a better technical solution for current logistics systems. In autonomous logistics, the decision making is shifted toward the logistic objects which are defined as material items (e.g., vehicles, containers) or immaterial items (e.g., customer orders) of a networked logistics system. These objects have the ability to interact with each other and make decisions according to their own objectives. In the technical aspect, with the rapid development of innovative sensor technology, namely Wireless Sensor Networks (WSNs), each element in the network can selforganize and interact with other elements for information transmission. The attachment of an electronic sensor element into a logistic object will create an autonomous environment in both the communication and the logistic domain. With this idea, the requirements of logistics can be fulfilled; for example, the monitoring data can be precise, comprehensive and timely. In addition, the goods flow management can be transferred to the information logistic object management, which is easier by the help of information technologies. However, in order to transmit information between these logistic objects, one requirement is that a routing protocol is necessary. The Opportunistic relative Distance-Enabled Uni-cast Routing (ODEUR) protocol which is proposed and investigated in this thesis shows that it can be used in autonomous environments like autonomous logistics. Moreover, the support of mobility, multiple sinks and auto-connection in this protocol enhances the dynamics of logistic objects. With a general model which covers a range from low-level issues to high-level protocols, many services such as real time monitoring of environmental conditions, context-aware applications and localization make the logistic objects (embedded with sensor equipment) more advanced in information communication and data processing. The distributed management service in each sensor node allows the flexible configuration of logistic items at any time during the transportation. All of these integrated features introduce a new technical solution for smart logistic items and intelligent transportation systems. In parallel, a management system, WSN data Collection and Management System (WiSeCoMaSys), is designed to interact with the deployed Wireless Sensor Networks. This tool allows the user to easily manipulate the sensor networks remotely. With its

Modeling and Implementation of Wireless Sensor Networks for Logistics Applications

A distributed protocol which specifies how modes select at random a subset of their adjacent link is described. The protocol results in a routing topology with nodal degree that does not exceed a predetermined limit, and allows late entries to be incorporated into the network and partitioned networks to be reconstituted. Simulation of the protocol has demonstrated a threshold effect for global network connectivity with respect to the average nodal degree. Moreover, if nodes are allowed to operate with their degree above the threshold, the probability that the protocol results in a connected routing graph is very close to one. That probability decreases sharply to zero as the nodal maximum degree drops below the threshold. Specifically, the threshold has been found to be between 3 and 7 for a large variety of network configuration and protocol conditions. >

http://ieeexplore.ieee.org/iel4/720/553/00013608.pdf

N. Shacham

Papers

A distributed protocol for reducing neighborhood size in radio networks