Abstract: Frequency-dependent cancellation separates a plurality of interfering signals received by a plurality of receivers. Received wideband single-carrier signals or multicarrier signals are separated into a plurality of narrowband subcarriers. Sub-carrier frequencies and frequency-band characteristics may be selected with respect to channel characteristics (e.g., coherence bandwidth, interference, etc.). A cancellation circuit provides complex weights to the sub-carrier components. Weighted components associated with each sub-carrier frequency are combined to separate a plurality of interfering signals. Optionally, a plurality of the separated subcarriers may be combined to reconstruct at least one transmitted single-carrier signal from a plurality of frequency components.

Abstract: A wireless communication system transmits data on multiple carriers simultaneously to provide frequency diversity. Carrier interference causes a narrow pulse in the time domain when the relative phases of the multiple carriers are zero. Selection of the frequency separation and phases of the carriers controls the timing of the pulses. Both time division of the pulses and frequency division of the carriers achieves multiple access. Carrier interferometry is a basis from which other communication protocols can be derived. Frequency hopping and frequency shifting of the carriers does not change the pulse envelope if the relative frequency separation and phases between the carriers are preserved. Direct sequence CDMA signals are generated in the time domain by a predetermined selection of carrier amplitudes. Each pulse can be sampled in different phase spaces at different times. This enables communication in phase spaces that are not detectable by conventional receivers.

Abstract: A cancellation circuit removes interfering signals from desired signals in electrical systems having antennas or other electromagnetic pickup systems. The cancellation circuit provides amplitude adjustment and phase adjustment to electrical signals induced in an electrical system by received electromagnetic signals. The cancellation circuit may be adapted to process received electromagnetic waves having multiple frequencies. Phase adjustment compensates for electrical path-length differences between signals resulting from propagation delays, circuit delays, and multipath. The amplitude-adjusted and phase-adjusted signals are combined to cancel the effects of electromagnetic interference. In an electromagnetic receiver, a plurality of receiver elements provide the cancellation circuit with different complex proportions of desired and interfering signals to enable removal of the interfering signals.

Abstract: A cancellation circuit removes interfering signals from desired signals in electrical systems having antennas or other electromagnetic pickup systems. The cancellation circuit provides amplitude adjustment and phase adjustment to electrical signals induced in an electrical system by received electromagnetic signals. The amplitude-adjusted and phase-adjusted signals are combined to cancel the effects of electromagnetic interference. In an electromagnetic receiver, a plurality of receiver elements provide the cancellation circuit with different proportions of desired and interfering signals to enable removal of the interfering signals. An electromagnetic-wave transmitter having multiple transmitter elements is provided with a cancellation circuit for canceling electromagnetic signals in at least one predetermined region of space.