Abstract: A method and apparatus which can significantly reduce the matched filter requirements in decoding cyclic block codes, and is particularly advantageous for decoding maximal length block codes, and other cyclic block codes in which the number of codewords is .ltoreq.2.sup.k where .sup.k is the number of data bits encoded into each codeword. The signal containing the codeword is concatenated with itself, then the concatenated signal is applied to a matched filter to provide a peaking signal at some point in time as the concatenated signal is passed through the matched filter. The position of the peaking signal relative to a predetermined instant of time is sensed whereby the identity of the codeword (and thus data) can be determined.

Abstract: A satellite communications system provides automatic channel assignment without employing a dedicated signalling channel. A major station detects carrier-free forward channels and transmits on each a forward signal. A minor station hunts all available forward channels to ascertain and then monitor a carrier-free forward channel, detects the major station's forward signal and transmits a response signal on the corresponding carrier-free return channel while temporarily inhibiting reception by the minor station of any other signal from any other major station. The major station monitors all carrier-free return channels and detects the response signal to establish a link.