Method of transmitting digital signals, corresponding transmission system, signal and computer program product therefor

摘要

Digital signals are transmitted over a communication channel having a given bandwidth, by simultaneously transmitting: one or more Spread Spectrum signals, such as, Code Division Multiple Access signals, wherein the spectrum of the Spread Spectrum signals exhibits roll-off transition bands at the boundaries of the spectrum, and one or more multi-carrier transmission signals, such as, Orthogonal Frequency Division Multiplexing signals, which are transmitted over the transition bands of the Spread Spectrum signals.

主权项

1. A method of transmitting digital signals over a communication channel having a given bandwidth, comprising:
transmitting over said channel at least one spread spectrum signal comprising at least one code division multiple access signal, wherein a spectrum of said at least one spread spectrum signal comprises:
a nearly flat portion wherein a power spectral density of said at least one spread spectrum signal is around a maximum value; androll-off transition bands at both boundaries of said nearly flat portion wherein said power spectral density decreases from said maximum value to a predefined minimum value; and simultaneously transmitting over said channel a plurality of multi-carrier transmission signals over at least one of said transition bands, wherein a number of said multi-carrier transmission signals in said plurality of multi-carrier transmission signals is determined as a function of at least:
interference generated by said multi-carrier transmission signals on said at least one spread spectrum signal; andinterference generated by said at least one spread spectrum signals on said multi-carrier transmission signals,wherein said number of said multi-carrier transmission signals is selected so that an amount of said interference generated by said multi-carrier transmission signals on said at least one spread spectrum signal may reach up to a fraction of an inter-cell interference value and/or an intra-cell interference value without significantly affecting a signal-to-noise-plus-interference ratio of said at last one spread spectrum signal.