An improved simplex ARQ system for data transmission circuits using a short wave circuit is provided. A block of characters is sent from a master station to a slave station and if an error occurs during the transmission, said block of characters is automatically re-transmitted, thus clean output without an error is obtained on a printer in a receiving or slave station. The length of said block is changed according to the instantaneous quality of the short wave circuit, and thus the actual transm…

A facsimile communication system equipped with an ARQ function for transmitting data in the form of a block between a transmitter and a receiver through a transmission route having a relatively large time delay, such as a submarine cable and communications satellite, is provided. In the system, prior to transmission of image data, a time delay in transmission of data through a selected transmission route is measured and the number of bits of data block is determined in accordance with the thus m…

An error control apparatus and method is disclosed, wherein a control message is used to request a retransmission of a received erroneous digital signal transmitted in a first direction via a transmission medium. The control message is transmitted in a second direction of said transmission medium, wherein the transmission rate of the control method is controlled in dependence on a usage of the transmission medium in the second direction and/or an amount of available memory in a receiving means (…

Forward and Reverse Channel Automatic Repeat reQuest (ARQ) communication is described in which a Forward Channel Automatic Repeat reQuest (ARQ) session between a first unit and a second unit is performed, in which a command is send to the second unit to start a forward channel ARQ session, where the command includes a message length field specifying the length of an ARQ message to be sent by the first unit to the second unit. The second unit may refuse the command because of the length of the AR…

An automatic retransmission system offering good latency and overhead characteristics combined with programmable tradeoffs among overhead, latency, and error performance. ARQ (Automatic Repeat reQuest) blocks present at both ends of a link coordinate to automatically attempt to re-send data if that data was not received properly the first time it was sent. Re-transmission from the transmitter (transmitter) is requested by the receiver (Receiver) via a highly reliable “Repeat Request” (RR) mechan…

A hybrid ARQ scheme is used incremental data packet combining. In an example embodiment, the hybrid ARQ scheme with incremental data packet combining employs three feedback signaling commands: ACK, NACK, and LOST. Using these three feedback commands, the hybrid ARQ scheme with incremental data packet combining provides both robustness and good performance. This scheme is particularly advantageous in communication systems with unreliable communication channels, e.g., a fading radio channel, where…

The present invention provides a flexible ARQ scheme. A communications channel is set up between a transmitter and a receiver. A value is selected for an ARQ parameter for data packets to be transmitted over the communications channel. The ARQ parameter value may be selected in accordance with a trade-off between a desired performance or goal, e.g., a specific throughput of data packets transmitted over the communications channel, and one or more communication resources required to support the d…

An automatic retransmission system offering good latency and overhead characteristics combined with programmable tradeoffs among overhead, latency, and error performance. ARQ (Automatic Repeat reQuest) blocks present at both ends of a link coordinate to automatically attempt to re-send data if that data was not received properly the first time it was sent. Re-transmission from the transmitter (transmitter) is requested by the receiver (Receiver) via a highly reliable “Repeat Request” (RR) mechan…

A communication system comprises a downlink data channel for the transmission of data packets from a primary station to a secondary station and two uplink control channels, a first channel for transmission of status signals to indicate the status of received data packets and a second channel for transmission of pilot information. In operation, on detection (402) of a data packet the secondary station increases (404) the transmission power of the second channel, thereby enabling the primary stati…

A method and apparatus for communicating a message from a transmitting station to a remote receiving station by adaptively selecting a retransmission protocol from two or more retransmission protocols based on at least one changing transmission variable is described herein. The transmitting station transmits a first version of the message in a first transmission. When the previous transmission was unsuccessful, a controller adaptively selects either the first version of the message or a second v…