Abstract: A method for use in a communication network having multiple users and limited bandwidth, wherein up to N users are allocated to the same frequency band at the same time, and the method provides for processing signals received at an M-element antenna array, using a cumulant-based signal recovery system to separate and recover the signals transmitted by the respective users.

Abstract: A method and apparatus for processing cochannel signals received at a sensor array in a cumulant-based signal processing and separation engine to obtain a desired set of output signals or parameters. For use in a signal recovery system, the output signals are recovered and separated versions of the originally transmitted cochannel signals. An important feature that distinguishes the cumulant-based system from other signal separation and recovery systems is that it generates an estimated generalized steering vector associated with each signal source, and representative of all received coherent signal components attributable to the source. This feature enables the invention to perform well in multipath conditions, by combining all coherent multipath components from the same source. In a receiver/transmitter system, the estimated generalized steering vectors associated with each source are used to generate transmit beamformer weight vectors that permit cochannel transmission to multiple user stations.

Abstract: Method and apparatus for separating signals transmitted over a waveguide using different propagation modes in overlapping frequency bands. The signals are received at an array of probes installed in an operative relationship to the waveguide, and are separated using a recovery system based on cumulants of the fourth or higher even order.

Abstract: Apparatus for transmitting and receiving signals over a fiber-optic waveguide using different frequency bands of light, i.e. by wavelength division multiplexing. A plurality of signal couplers interfaces modulated signals onto the waveguide in separate optical frequency bands, and a plurality of signal probes forming a probe array at one or more places in the waveguide, receives the signals, which are subject to scrambling and distortion as a result of physical irregularities in the waveguide. A recovery system coupled to the signal probes effects recovery and separation of the received signals using cumulant computations based on cumulants of the fourth or higher even order.

Abstract: Method and apparatus for complex phase equalization in a communication system. The method includes receiving and downconverting a two-dimensional communication signal to generate in-phase (I) and quadrature (Q) components that have been phase-rotated by an unknown amount during propagation from a transmitter, and then processing the I and Q signals in a cumulant recovery processing system to obtain phase correction of the I and Q signals prior to demodulation. The final step is demodulating the two-dimensional communication signal. Phase correction is effected without regard to modulation type and independently of the demodulating step.

Abstract: A method for processing received radio signals that are subject to unwanted change during propagation through the atmosphere, from a transmitter to a receiver array. The multiple signals are received as cochannel signals at the antenna array, and are processed to eliminate the effects of modification of the signals during propagation, wherein the processing step includes cumulant-based signal recovery without regard for the geometrical properties of the antenna array. In the invention as disclosed, two different information signals having two different polarization states are transmitted, and at least one of the transmitted signals is subjected to an unwanted change of its polarization state. The received signals are processed to separate and recover the two information signals without regard to their polarization states.

Abstract: A method and apparatus for processing cochannel signals received at a sensor array in a cumulant-based signal processing and separation engine to obtain a desired set of output signals or parameters. For use in a signal recovery system, the output signals are recovered and separated versions of the originally transmitted cochannel signals. An important feature that distinguishes the cumulant-based system from other signal separation and recovery systems is that it generates an estimated generalized steering vector associated with each signal source, and representative of all received coherent signal components attributable to the source. This feature enables the invention to perform well in multipath conditions, by combining all coherent multipath components from the same source. In a receiver/transmitter system, the estimated generalized steering vectors associated with each source are used to generate transmit beamformer weight vectors that permit cochannel transmission to multiple user stations.