Adaptive modulation is a transmission scheme in digital communications where the transmitter adapts its transmission mode in accordance with the channel. Depending on the condition of the channel, the transmitter could be adapting one or more of the following: constellation size, code rate, and power. Digital communication, as opposed to analogue communication refers to all emerging communications and technologies via a digital platform usually combining text, graphics, sound, and video, utilising computer or mobile technology. ... Antenna tower of Crystal Palace transmitter, London A transmitter (sometimes abbreviated XMTR) is an electronic device which with the aid of an antenna propagates an electromagnetic signal such as radio, television, or other telecommunications. ... A Communications channel (or channel for short), models the medium through which information is transmitted from a sender (or transmitter) to a receiver. ... In telecommunications and computing, bit rate (sometimes written bitrate) is the frequency at which bits are passing a given (physical or metaphorical) point. It is quantified using the bit per second (bit/s) unit. ... Transmitter power output (TPO) is the actual amount of power (in watts) of RF energy that a transmitter produces at its output. ...

Adaptive modulation systems invariably require some channel information at the transmitter. This could be acquired in time division duplex systems by assuming the channel from the transmitter to the receiver is approximately the same as the channel from the receiver to the transmitter. Alternatively, the channel knowledge can also be directly measured at the receiver, and fed back to the transmitter. Adaptive modulation systems improve rate of transmission, and/or bit error rates, by exploiting the channel information that is present at the transmitter. Especially over fading channels which model wireless propagation environments, adaptive modulation systems exhibit great performance enhancements compared to systems that do not exploit channel knowledge at the transmitter. Duplex is the having of two principal elements or parts. ... The receiver in information theory is the receiving end of a communication channel (in particular the binary symmetric channel) in information theory. ... In telecommunication, an error ratio is the ratio of the number of bits, elements, characters, or blocks incorrectly received to the total number of bits, elements, characters, or blocks sent during a specified time interval. ... This is about the phenomenon of loss of signal in telecommunications. ... Wireless is an old-fashioned term for a radio transceiver (a mixed receiver and transmitter device), referring to its use in wireless telegraphy early on, or for a radio receiver. ...