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Relay Channel
In information theory, a relay channel is a probability model of the communication between a sender and a receiver aided by one or more intermediate relay nodes. General discrete-time memoryless relay channel A discrete memoryless single-relay channel can be modelled as four finite sets, X_1, X_2, Y_1, and Y, and a conditional probability distribution p(y,y_1, x_1,x_2) on these sets. The probability distribution of the choice of symbols selected by the encoder and the relay encoder is represented by p(x_1,x_2). o------------------o , Relay Encoder , o------------------o Λ , , y1 x2 , , V o---------o x1 o------------------o y o---------o , Encoder , --->, p(y,y1, x1,x2) , --->, Decoder , o---------o o------------------o o---------o There exist three main relaying schemes: Decode-and-Forward, Compress-and-Forward and Amplify-an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Information Theory
Information theory is the scientific study of the quantification (science), quantification, computer data storage, storage, and telecommunication, communication of information. The field was originally established by the works of Harry Nyquist and Ralph Hartley, in the 1920s, and Claude Shannon in the 1940s. The field is at the intersection of probability theory, statistics, computer science, statistical mechanics, information engineering (field), information engineering, and electrical engineering. A key measure in information theory is information entropy, entropy. Entropy quantifies the amount of uncertainty involved in the value of a random variable or the outcome of a random process. For example, identifying the outcome of a fair coin flip (with two equally likely outcomes) provides less information (lower entropy) than specifying the outcome from a roll of a dice, die (with six equally likely outcomes). Some other important measures in information theory are mutual informat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Probability
Probability is the branch of mathematics concerning numerical descriptions of how likely an Event (probability theory), event is to occur, or how likely it is that a proposition is true. The probability of an event is a number between 0 and 1, where, roughly speaking, 0 indicates impossibility of the event and 1 indicates certainty."Kendall's Advanced Theory of Statistics, Volume 1: Distribution Theory", Alan Stuart and Keith Ord, 6th Ed, (2009), .William Feller, ''An Introduction to Probability Theory and Its Applications'', (Vol 1), 3rd Ed, (1968), Wiley, . The higher the probability of an event, the more likely it is that the event will occur. A simple example is the tossing of a fair (unbiased) coin. Since the coin is fair, the two outcomes ("heads" and "tails") are both equally probable; the probability of "heads" equals the probability of "tails"; and since no other outcomes are possible, the probability of either "heads" or "tails" is 1/2 (which could also be written ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Communication
Communication (from la, communicare, meaning "to share" or "to be in relation with") is usually defined as the transmission of information. The term may also refer to the message communicated through such transmissions or the field of inquiry studying them. There are many disagreements about its precise definition. John Peters argues that the difficulty of defining communication emerges from the fact that communication is both a Universality (philosophy), universal phenomenon and a Communication studies, specific discipline of institutional academic study. One definitional strategy involves limiting what can be included in the category of communication (for example, requiring a "conscious intent" to persuade). By this logic, one possible definition of communication is the act of developing Semantics, meaning among Subject (philosophy), entities or Organization, groups through the use of sufficiently mutually understood signs, symbols, and Semiosis, semiotic conventions. An im ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Communication Source
A source or sender is one of the basic concepts of communication and information processing. Sources are objects which encode message data and transmit the information, via a channel, to one or more observers (or receivers). In the strictest sense of the word, particularly in information theory, a ''source'' is a process that generates message data that one would like to communicate, or reproduce as exactly as possible elsewhere in space or time. A source may be modelled as memoryless, ergodic, stationary, or stochastic, in order of increasing generality. ''Communication Source'' combines ''Communication and Mass Media Complete'' and ''Communication Abstracts'' to provide full-text access to more than 700 journals, and indexing and abstracting for more than 1,000 core journals. Coverage dating goes back to 1900. Content is derived from academic journals, conference papers, conference proceedings, trade publications, magazines and periodicals. A transmitter can be either a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cooperative Diversity
Cooperative diversity is a cooperative multiple antenna technique for improving or maximising total network channel capacities for any given set of bandwidths which exploits user diversity by decoding the combined signal of the relayed signal and the direct signal in wireless multihop networks. A conventional single hop system uses direct transmission where a receiver decodes the information only based on the direct signal while regarding the relayed signal as interference, whereas the cooperative diversity considers the other signal as contribution. That is, cooperative diversity decodes the information from the combination of two signals. Hence, it can be seen that cooperative diversity is an antenna diversity that uses distributed antennas belonging to each node in a wireless network. Note that user cooperation is another definition of cooperative diversity. ''User cooperation'' considers an additional fact that each user relays the other user's signal while cooperative diversit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Relay (other)
A relay is an electric switch operated by a signal in one circuit to control another circuit. Relay may also refer to: Historical * Stage station, a place where exhausted horses being used for transport could be exchanged for fresh ones * Cursus publicus, a courier service in the Roman Empire * Relay league, a chain of message-forwarding stations Computer networking * BITNET Relay, a 1980s online chat system * Mail relay, a server used for forwarding e-mail ** Open mail relay, such a server that can be used by anyone Other telecommunication * Relay (satellite) * Broadcast relay station, a transmitter which repeats or transponds the signal of another * Microwave radio relay * Relay channel, in information theory, a communications probability modeling system * Telecommunications Relay Service, a telephone accessibility service for the deaf * Repeater, an electronic device that receives and retransmits a signal Automobiles * Citroën Relay, a marketing name for the Fiat Ducat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Information Theory
Information theory is the scientific study of the quantification (science), quantification, computer data storage, storage, and telecommunication, communication of information. The field was originally established by the works of Harry Nyquist and Ralph Hartley, in the 1920s, and Claude Shannon in the 1940s. The field is at the intersection of probability theory, statistics, computer science, statistical mechanics, information engineering (field), information engineering, and electrical engineering. A key measure in information theory is information entropy, entropy. Entropy quantifies the amount of uncertainty involved in the value of a random variable or the outcome of a random process. For example, identifying the outcome of a fair coin flip (with two equally likely outcomes) provides less information (lower entropy) than specifying the outcome from a roll of a dice, die (with six equally likely outcomes). Some other important measures in information theory are mutual informat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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