Optimal carrier frequency assignment for upgrading radio-frequency-channel preserving no triple crosstalk

摘要

Base on discussing the relationship between number of triple crosstalks and number of carrier frequencies, this paper presents two kinds of methods to increase number of carrier frequencies preserving no triple crosstalk. One is using different optimal carrier frequency' sequences of no triple crosstalk. Another is using subset of one optimal carrier frequency of no triple crosstalk. Three theorems about optimal carrier frequency' sequences of no triple crosstalk are given in this paper. The result of simulation shows that suitable unequally carrier frequencies' separations can be found for which no triple crosstalk product term is superimposed on any of the transmitted channels, and the bandwidth expansion factor is not always increasing, and the span between the triple crosstalks and carrier frequencies are not always decreasing, when increasing system carrier frequencies. Eight-carrier frequencies' system is an example to show how to use the methods to assign the carrier frequency. The methods can be applied in the LEO/MEO satellite mobile communication system, especially for CDMA (code-division multipe-access) and FDMA (frequency-division multiple-access) system.