Near-term digital radio

Last updated May 19, 2019

The Near-term digital radio (NTDR) program provided a prototype mobile ad hoc network (MANET) radio system to the United States Army, starting in the 1990s. The MANET protocols were provided by Bolt, Beranek and Newman; the radio hardware was supplied by ITT.^[1] These systems have been fielded by the United Kingdom as the High-capacity data radio (HCDR) and by the Israelis as the Israeli data radio. They have also been purchased by a number of other countries for experimentation.

A mobile ad hoc network (MANET), also known as wireless ad hoc network or ad hoc wireless network, is a continuously self-configuring, infrastructure-less network of mobile devices connected wirelessly.

High-capacity data radio (HCDR) is a development of the Near-Term Digital Radio (NTDR) for the UK government as a part of the Bowman communication system. It is a secure wideband 225–450 MHz UHF radio system that provides a self-managing IP-based Internet backbone capability without the need for other infrastructure communications.

The NTDR protocols consist of two components: clustering and routing. The clustering algorithms dynamically organize a given network into cluster heads and cluster members. The cluster heads create a backbone; the cluster members use the services of this backbone to send and receive packets. The cluster heads use a link-state routing algorithm to maintain the integrity of their backbone and to track the locations of cluster members.

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The NTDR routers also use a variant of Open Shortest Path First (OSPF) that is called Radio-OSPF (ROSPF). ROSPF does not use the OSPF hello protocol for link discovery, etc. Instead, OSPF adjacencies are created and destroyed as a function of MANET information that is distributed by the NTDR routers, both cluster heads and cluster members. It also supported multicasting.^[2]

Open Shortest Path First (OSPF) is a routing protocol for Internet Protocol (IP) networks. It uses a link state routing (LSR) algorithm and falls into the group of interior gateway protocols (IGPs), operating within a single autonomous system (AS). It is defined as OSPF Version 2 in RFC 2328 (1998) for IPv4. The updates for IPv6 are specified as OSPF Version 3 in RFC 5340 (2008). OSPF supports the Classless Inter-Domain Routing (CIDR) addressing model.

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A wireless ad hoc network (WANET) or MANET is a decentralised type of wireless network. The network is ad hoc because it does not rely on a pre-existing infrastructure, such as routers in wired networks or access points in managed (infrastructure) wireless networks. Instead, each node participates in routing by forwarding data for other nodes, so the determination of which nodes forward data is made dynamically on the basis of network connectivity and the routing algorithm in use.
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A routing protocol specifies how routers communicate with each other, distributing information that enables them to select routes between any two nodes on a computer network. Routers perform the "traffic directing" functions on the Internet; data packets are forwarded through the networks of the internet from router to router until they reach their destination computer. Routing algorithms determine the specific choice of route. Each router has a prior knowledge only of networks attached to it directly. A routing protocol shares this information first among immediate neighbors, and then throughout the network. This way, routers gain knowledge of the topology of the network. The ability of routing protocols to dynamically adjust to changing conditions such as disabled data lines and computers and route data around obstructions is what gives the Internet its survivability and reliability.

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Associativity-based routing is a mobile routing protocol invented for wireless ad hoc networks, also known as mobile ad hoc networks (MANETs) and wireless mesh networks. ABR was invented in 1993, filed for a U.S. patent in 1996, and granted the patent in 1999. ABR was invented by Chai Keong Toh while doing his Ph.D. at Cambridge University.

References

↑ L. Williams, L. Emory, "Near Term Digital Radio - a first look", Proceedings of the 1996 Tactical Communications Conference. Ensuring Joint Force Superiority in the Information Age, 30 April-2 May 1996.
↑ B. Welsh, N. Rehn, B. Vincent, J. Weinstein, and S. Wood, "Multicasting with the near term digital radio (NTDR) in the Tactical Internet", IEEE Military Communications Conference Proceedings, MILCOM 98, 19-21 Oct. 1998.

Ruppe, R; Griswald, S; Walsh, P; Martin, R (2 December 1997). "Near term digital radio (NTDR) system". pp. 1282–1287 vol.3. doi:10.1109/MILCOM.1997.644974 . Retrieved 18 January 2018.

In computing, a Digital Object Identifier or DOI is a persistent identifier or handle used to identify objects uniquely, standardized by the International Organization for Standardization (ISO). An implementation of the Handle System, DOIs are in wide use mainly to identify academic, professional, and government information, such as journal articles, research reports and data sets, and official publications though they also have been used to identify other types of information resources, such as commercial videos.

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[1] L. Williams, L. Emory, "Near Term Digital Radio - a first look", Proceedings of the 1996 Tactical Communications Conference. Ensuring Joint Force Superiority in the Information Age, 30 April-2 May 1996.

[2] B. Welsh, N. Rehn, B. Vincent, J. Weinstein, and S. Wood, "Multicasting with the near term digital radio (NTDR) in the Tactical Internet", IEEE Military Communications Conference Proceedings, MILCOM 98, 19-21 Oct. 1998.