| 摘要 |
PURPOSE:To prevent the reduction in the transmission efficiency due to the deterioration in the line quality by making the control of an error control system more accurate in the broadcast communication based on the same principle and using repetitively N sets of consecutive sequential numbers so as to reduce number of retransmission frames. CONSTITUTION:Let number N of basic transmission frames be 6, e.g. when information frames of sequential numbers 0-5 are sent, at first a reception station 1 discriminates an error in information frames whose sequential numbers 1 and 3 and a reception station 2 discriminates an error in the frames whose numbers are 2 and 5, they are subjected to reproduction request respectively. Since an error frame in any reception station among 6 frames is at most one, a transmission station makes a frame group with a minimum number to cover all errors. That is, since two frames each whose number differs in each frame number are in error in the reception stations 1,2, two sets of XOR groups 1,2 are generated. In order to inform which of frames is used for an object to XOR, a re-transmission XOR frame identifier is added as control information and the reception station aborts an undesired XOR frame and a new frame is decoded. |
