Reachback

Abstract: : Beginning in 2002, a team of Naval Postgraduate School researchers together with sponsors from the United States Special Operations Command (USSOCOM), and later joined by the Office of the Secretary of Defense (OSD) and the Department of Homeland Security (DHS) S&T Programs, started a new interagency experimentation program, which is now collectively known as the Tactical Network Testbed (TNT) Experiments. An observed general lack of synergy between military operators, government labs, industry, and the academic community in resolving increasingly complex problems of integrating and operating emerging technologies motivated the project. In the core of TNT experimentation is a unique testbed, which enables sustainability and evolution of the experimentation process. It provides for the adaptation and integration processes between people, networks, sensors, and unmanned systems. It enables plug-and-play tactical-on-the-move sensor-unmanned systems networking capabilities combined with global reachback to remote expert/ command sites and augmentation by rapid integration of applied research services. The goal for this paper is to describe an innovative interagency experimentation testbed environment which has evolved into a unique research service of social and information networking, enabling synergy of the military, academic, government, and industrial communities in designing, operating, and evaluating emerging self-organizing tactical networks as well as other related technologies.

Abstract: This paper describes the problem of communicating over broadcast channels (BCs) with partially cooperating receivers. In our setup receivers are able to exchange messages over conference links, prior to making their decisions. This problem comes up naturally in a sensor networking application, where a transmitter external to the sensor network wants to download data into the network to, e.g., configure the sensor array. We find the capacity region for the case where the BC is degraded. This region is a strict enlargement of the classical region for the degraded BC without cooperation in [T.M. Cover,(1998)].

Abstract: A Reachback email system includes methods and software products for intercepting a sent email message from an email client, algorithmically determining a first Reachback URL from an email address of the email client, adding the first Reachback URL to the sent email message to form a sent Reachback email message, digitally signing the sent Reachback email message, sending the sent Reachback email message to at least one recipient, publishing Reachback validation information (RVI) accessible by the at least one recipient using the first Reachback URL, intercepting a received Reachback email message before delivery to the email client, retrieving RVI for the received Reachback email message using a Reachback URL, validating the RVI, the Reachback URL and the Reachback email message contents, providing an indication of the Reachback email message validation, and delivering the received Reachback email message to the email client.

Abstract: We consider a multiaccess communication problem, in which multiple sources want to send correlated data to a far receiver, over a multiple access channel that is rendered virtually collision free by a suitable MAC protocol. This problem arises, e.g., in the context of sensor networks, where sensors are deployed on a field, and the goal is to send back to a remote location the signals picked up by all nodes. In this paper, we give an exact characterization of the joint source/channel capacity region, i.e., we give conditions on the sources and the channels under which reliable communication is possible in this context. These conditions generalize in a very meaningful way the condition that (entropy of a source less than channel capacity) for point-to-point channels, and surprisingly, give a separation theorem for this problem as well—we know of no other network information theory problem for which source and channel separation holds.