Abstract: A method of transmitting signals from a base station towards user terminals in a cellular communication system. The method includes generating diversity signals, wherein at least one of the diversity signals is subjected to a selectively variable RF phase shift. Specifically, a set of radio link quality indicators is determined at the base station, wherein each radio link quality indicator is representative of the quality of the radio link between the base station and a respective one of the user terminals. The set of radio link quality indicators is used to generate an aggregated radio quality indicator, which in turn is used to selectively vary the variable RF phase shift. For example, the phase shift may be selected, which optimizes the aggregated radio quality indicator.

Abstract: A tunable delay line for radiofrequency or microwave frequency applications consists of at least one ridge waveguide in which the ridge is movable in the waveguide body so as to vary the width of an air gap defined between the longitudinal end surface of the ridge and a confronting member of the waveguide. The ridge is moved by an actuator external to the waveguide body.

Abstract: A system for diversity processing two signals transmitted and/or received via two diversity antennas includes at least four respective propagation paths coupling the signals to the two diversity antennas. Diversity processing is primarily in the form of decorrelation achieved by means of time variable delay elements that apply time variable delays to the signals propagating over at least two of the propagation paths in the system. The related processing may take place either at RF or IF, or at baseband, whereby the time variable delays are applied by subjecting the baseband signals to multiplication by a complex signal.

Abstract: A system for diversity processing a signal propagated via two diversity antennas includes: respective propagation paths for propagating two replicas of the signal, these propagation paths being coupled to the two diversity antennas so that the replicas are propagated via different antennas; a time variable delay element for subjecting at least one of the replicas to a time variable delay; and a level adjusting element, such as an asymmetric splitter, to produce a level imbalance between the power levels of the replicas propagated via the two diversity antennas.

Abstract: A system for transmitting a signal via diversity antennas includes at least one delay element for generating at least one delayed replica of the signal subject to a given delay, the signal and the at least one delayed replica being adapted to be transmitted via the diversity antennas, and a control unit for the at least one delay element for varying the given delay, whereby the signal and the at least one delayed replica, transmitted via the diversity antennas, give rise to alternate constructive and destructive combinations therebetween.

Abstract: A differential delay element for use, e.g., in selectively delaying RF signals in telecommunication systems includes a first microstrip circuit and a second microstrip circuit arranged side-by-side in a facing relationship. The first microstrip circuit defines a first delayed travel path for a first signal from a first input port to a first output port and the second microstrip circuit defines a second delayed travel path for a second signal from a second input port to a second output port. A perturber is arranged between the first and second microstrip circuits, displaceable toward and away from the first and second microstrip circuits, so that when the distance of the perturber to one of the microstrip circuits increases, the distance of the perturber to the other of the microstrip circuits decreases and viceversa.

Abstract: A method of transmitting signals from a base station towards user terminals in a cellular communication system. The method includes generating diversity signals, wherein at least one of the diversity signals is subjected to a selectively variable RF phase shift. Specifically, a set of radio link quality indicators is determined at the base station, wherein each radio link quality indicator is representative of the quality of the radio link between the base station and a respective one of the user terminals. The set of radio link quality indicators is used to generate an aggregated radio quality indicator, which in turn is used to selectively vary the variable RF phase shift. For example, the phase shift may be selected, which optimizes the aggregated radio quality indicator.

Abstract: A tunable delay line for radiofrequency or microwave frequency applications consists of at least one ridge waveguide in which the ridge is movable in the waveguide body so as to vary the width of an air gap defined between the longitudinal end surface of the ridge and a confronting member of the waveguide. The ridge is moved by an actuator external to the waveguide body.

Abstract: A system for diversity processing two signals transmitted and/or received via two diversity antennas includes at least four respective propagation paths coupling the signals to the two diversity antennas. Diversity processing is primarily in the form of decorrelation achieved by means of time variable delay elements that apply time variable delays to the signals propagating over at least two of the propagation paths in the system. The related processing may take place either at RF or IF, or at baseband, whereby the time variable delays are applied by subjecting the baseband signals to multiplication by a complex signal.

Abstract: A differential delay element for use, e.g., in selectively delaying RF signals in telecommunication systems includes a first microstrip circuit and a second microstrip circuit arranged side-by-side in a facing relationship. The first microstrip circuit defines a first delayed travel path for a first signal from a first input port to a first output port and the second microstrip circuit defines a second delayed travel path for a second signal from a second input port to a second output port. A perturber is arranged between the first and second microstrip circuits, displaceable toward and away from the first and second microstrip circuits, so that when the distance of the perturber to one of the microstrip circuits increases, the distance of the perturber to the other of the microstrip circuits decreases and viceversa.

Abstract: A system for diversity processing a signal propagated via two diversity antennas includes: respective propagation paths for propagating two replicas of the signal, these propagation paths being coupled to the two diversity antennas so that the replicas are propagated via different antennas; a time variable delay element for subjecting at least one of the replicas to a time variable delay; and a level adjusting element, such as an asymmetric splitter, to produce a level imbalance between the power levels of the replicas propagated via the two diversity antennas.

Abstract: A system for transmitting a signal via diversity antennas includes at least one delay element for generating at least one delayed replica of the signal subject to a given delay, the signal and the at least one delayed replica being adapted to be transmitted via the diversity antennas, and a control unit for the at least one delay element for varying the given delay, whereby the signal and the at least one delayed replica, transmitted via the diversity antennas, give rise to alternate constructive and destructive combinations therebetween.