| 摘要 |
Signals which have been previously relayed by a repeater station are subtracted, so that the transmission bandwidth may be re-used. The transmitting and receiving stations may be provided at randomly distributed locations and a chain may be formed of repeated signals. By subtracting the signal now being transmitted by subsequent repeater stations in the chain, interference is reduced. The relay chain may use two alternating frequency channels to transmit the signal, and may delay the repetition until a later time. The cancellation may be performed by differencing means of the signal previously relayed, delayed and passed through a linear filter. The filter minimises the output power of the differencing means or the correlation of the output and the earlier relayed transmission, and may be adjusted recursively. |
