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High-capacity Data Radio
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 (mobile phone, fixed communications). There is also an export version that incorporates Advanced Encryption Standard (AES) encryption rather than UK Government Type 1 Crypto. The radio offers a link throughput (terminal to terminal) of 500 kbit/s. A deployment of over 200 HCDR-equipped military vehicles can automatically configure and self manage into a fully connected autonomous mesh network intercommunicating using mobile ad hoc network (MANET) protocols. The radio is an IPv4-compliant three-port router having a radio port, Ethernet port and PPP serial port. The 20-watt radio has adaptive transmit power and adaptive forward error correcti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Near-Term Digital Radio
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. 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. 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. The NTDR routers also use a variant of Open Shortest Path First Ope ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ethernet
Ethernet () is a family of wired computer networking technologies commonly used in local area networks (LAN), metropolitan area networks (MAN) and wide area networks (WAN). It was commercially introduced in 1980 and first standardized in 1983 as IEEE 802.3. Ethernet has since been refined to support higher bit rates, a greater number of nodes, and longer link distances, but retains much backward compatibility. Over time, Ethernet has largely replaced competing wired LAN technologies such as Token Ring, FDDI and ARCNET. The original 10BASE5 Ethernet uses coaxial cable as a shared medium, while the newer Ethernet variants use twisted pair and fiber optic links in conjunction with switches. Over the course of its history, Ethernet data transfer rates have been increased from the original to the latest , with rates up to under development. The Ethernet standards include several wiring and signaling variants of the OSI physical layer. Systems communicating over Ethernet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
British Military Radio
British may refer to: Peoples, culture, and language * British people, nationals or natives of the United Kingdom, British Overseas Territories, and Crown Dependencies. ** Britishness, the British identity and common culture * British English, the English language as spoken and written in the United Kingdom or, more broadly, throughout the British Isles * Celtic Britons, an ancient ethno-linguistic group * Brittonic languages, a branch of the Insular Celtic language family (formerly called British) ** Common Brittonic, an ancient language Other uses *''Brit(ish)'', a 2018 memoir by Afua Hirsch *People or things associated with: ** Great Britain, an island ** United Kingdom, a sovereign state ** Kingdom of Great Britain (1707–1800) ** United Kingdom of Great Britain and Ireland (1801–1922) See also * Terminology of the British Isles * Alternative names for the British * English (other) * Britannic (other) * British Isles * Brit (other) * B ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Modem
A modulator-demodulator or modem is a computer hardware device that converts data from a digital format into a format suitable for an analog transmission medium such as telephone or radio. A modem transmits data by Modulation#Digital modulation methods, modulating one or more carrier wave signals to encode digital information, while the receiver Demodulation, demodulates the signal to recreate the original digital information. The goal is to produce a Signal (electronics), signal that can be transmitted easily and decoded reliably. Modems can be used with almost any means of transmitting analog signals, from light-emitting diodes to radio. Early modems were devices that used audible sounds suitable for transmission over traditional telephone systems and leased lines. These generally operated at 110 or 300 bits per second (bit/s), and the connection between devices was normally manual, using an attached telephone handset. By the 1970s, higher speeds of 1,200 and 2,400 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Modulation
In electronics and telecommunications, modulation is the process of varying one or more properties of a periodic waveform, called the ''carrier signal'', with a separate signal called the ''modulation signal'' that typically contains information to be transmitted. For example, the modulation signal might be an audio signal representing sound from a microphone, a video signal representing moving images from a video camera, or a digital signal representing a sequence of binary digits, a bitstream from a computer. The carrier is higher in frequency than the modulation signal. In radio communication the modulated carrier is transmitted through space as a radio wave to a radio receiver. Another purpose is to transmit multiple channels of information through a single communication medium, using frequency-division multiplexing (FDM). For example in cable television which uses FDM, many carrier signals, each modulated with a different television channel, are transported through a sing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antenna (radio)
In radio engineering, an antenna or aerial is the interface between radio waves propagating through space and electric currents moving in metal conductors, used with a transmitter or receiver. In transmission, a radio transmitter supplies an electric current to the antenna's terminals, and the antenna radiates the energy from the current as electromagnetic wave In physics, electromagnetic radiation (EMR) consists of waves of the electromagnetic (EM) field, which propagate through space and carry momentum and electromagnetic radiant energy. It includes radio waves, microwaves, infrared, (visib ...s (radio waves). In Receiver (radio), reception, an antenna intercepts some of the power of a radio wave in order to produce an electric current at its terminals, that is applied to a receiver to be Amplifier, amplified. Antennas are essential components of all radio equipment. An antenna is an array of conductor (material), conductors (Driven element, elements), elect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Forward Error Correction
In computing, telecommunication, information theory, and coding theory, an error correction code, sometimes error correcting code, (ECC) is used for controlling errors in data over unreliable or noisy communication channels. The central idea is the sender encodes the message with redundant information in the form of an ECC. The redundancy allows the receiver to detect a limited number of errors that may occur anywhere in the message, and often to correct these errors without retransmission. The American mathematician Richard Hamming pioneered this field in the 1940s and invented the first error-correcting code in 1950: the Hamming (7,4) code. ECC contrasts with error detection in that errors that are encountered can be corrected, not simply detected. The advantage is that a system using ECC does not require a reverse channel to request retransmission of data when an error occurs. The downside is that there is a fixed overhead that is added to the message, thereby requiring a h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Router (computing)
A router is a networking device that forwards data packets between computer networks. Routers perform the traffic directing functions between networks and on the global Internet. Data sent through a network, such as a web page or email, is in the form of data packets. A packet is typically forwarded from one router to another router through the networks that constitute an internetwork (e.g. the Internet) until it reaches its destination node. A router is connected to two or more data lines from different IP networks. When a data packet comes in on one of the lines, the router reads the network address information in the packet header to determine the ultimate destination. Then, using information in its routing table or routing policy, it directs the packet to the next network on its journey. The most familiar type of IP routers are home and small office routers that simply forward IP packets between the home computers and the Internet. More sophisticated routers, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bowman (communications System)
Bowman is the name of the tactical communications system used by the British Armed Forces. The Bowman C4I system consists of a range of HF radio, VHF radio and UHF radio sets designed to provide secure integrated voice, data services to dismounted soldiers, individual vehicles and command HQs up to Division level. Bowman has a number of specific applications installed on the base radio infrastructure known as BISAs. Bowman has been released incrementally as a number of phased capability releases, known as BCIP releases, with BCIP 5.5 being released in the field in 2013. Bowman replaced the Clansman series of radios. As of 2016, the MoD publicised plans to replace Bowman with a system named Morpheus. Procurement history The concept of Bowman dates from a 1989 UK MoD General Staff Requirement (GSR) for a system to replace the ageing Clansman radio system. The GSR was subsequently modified to accommodate post Cold War scenarios. The procurement had a long and chequered history, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IPv4
Internet Protocol version 4 (IPv4) is the fourth version of the Internet Protocol (IP). It is one of the core protocols of standards-based internetworking methods in the Internet and other packet-switched networks. IPv4 was the first version deployed for production on SATNET in 1982 and on the ARPANET in January 1983. It is still used to route most Internet traffic today, even with the ongoing deployment of Internet Protocol version 6 (IPv6), its successor. IPv4 uses a 32-bit address space which provides 4,294,967,296 (232) unique addresses, but large blocks are reserved for special networking purposes. History Internet Protocol version 4 is described in IETF publication RFC 791 (September 1981), replacing an earlier definition of January 1980 (RFC 760). In March 1982, the US Department of Defense decided on the Internet Protocol Suite (TCP/IP) as the standard for all military computer networking. Purpose The Internet Protocol is the protocol that defines and enables internet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mobile Ad Hoc Network
A wireless ad hoc network (WANET) or mobile ad hoc network (MANET) is a decentralized 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 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. In the Windows operating system, ad hoc is a communication mode (setting) that allows computers to directly communicate with each other without a router. Wireless mobile ad hoc networks are self-configuring, dynamic networks in which nodes are free to move. Such wireless networks lack the complexities of infrastructure setup and administration, enabling devices to create and join networks "on the fly". Each device in a MANET is free to move independently in any direction, and will therefore change it ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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