METHOD OF ERROR PROTECTED TRANSMISSION, METHOD OF ERROR PROTECTED RECEPTION OF DATA AND TRANSMISSION SYSTEM FOR TRANSMISSION OF DATA

摘要

Data is transmitted with a signal containing a number of simultaneously active modulated frequency channels. The data is encoded in an error protecting code. Successive data items are mapped pseudorandomly to different frequency channels. This protects against fading which affects frequency channels that are located at periodic distances from each other. The pseudorandom mapping is realized by writing the data items into memory in one order and reading them from memory in another order. Successive signals are each modulated in this way. The memory locations vacated upon reading for the modulation of one signal are filled by data items for modulating the next successive signal. This is kept up by permuting the order of the memory locations in which the data items are written for each successive signal.