Abstract: Systems and methods are disclosed herein for providing full orthogonality between simultaneously used beams, e.g., in a Multi-User Multiple-Input-Multiple-Output (MU-MIMO) radio system. In some embodiments, a radio system comprises an antenna system and a processing unit. The processing unit is adapted to determine an initial set of null locations for a particular beam based on an initial set of beam weighting factors for the particular beam, and change one or more of the initial null locations based on one or more other beams to be used simultaneously with the particular beam, thereby providing a new set of null locations for the particular beam. The processing unit is further adapted to compute a new set of beam weighting factors for the particular beam based on the new set of null locations, and utilize the new set of beam weighting factors to transmit or receive on the particular beam.

Abstract: A receiver (100) with an antenna array (150) provides interference reduction for blocking signals received by the receiver (100) by controlling different receiver blocks (110) associated with different antenna elements (112) of the array (150) differently, particularly for those antenna elements (112) in the corner or proximate a corner or edge of the array (150), responsive to a power level of a combined signal resulting from all antenna elements (112). As a result, the solution presented herein enables a receiver (100) to more accurately target the gain control such that the antenna elements (112) and associated receiver circuitry (110) most likely to be impacted by unwanted signals have a reduced gain, while the antenna elements (112) and associated receiver circuitry (110) less likely to be impacted by unwanted signals can operate with a higher gain.

Abstract: Systems and methods are disclosed herein for providing full orthogonality between simultaneously used beams, e.g., in a Multi-User Multiple-Input-Multiple-Output (MU-MIMO) radio system. In some embodiments, a radio system comprises an antenna system and a processing unit. The processing unit is adapted to determine an initial set of null locations for a particular beam based on an initial set of beam weighting factors for the particular beam, and change one or more of the initial null locations based on one or more other beams to be used simultaneously with the particular beam, thereby providing a new set of null locations for the particular beam. The processing unit is further adapted to compute a new set of beam weighting factors for the particular beam based on the new set of null locations, and utilize the new set of beam weighting factors to transmit or receive on the particular beam.

Abstract: A receiver (100) with an antenna array (150) provides interference reduction for blocking signals received by the receiver (100) by controlling different receiver blocks (110) associated with different antenna elements (112) of the array (150) differently, particularly for those antenna elements (112) in the corner or proximate a corner or edge of the array (150), responsive to a power level of a combined signal resulting from all antenna elements (112). As a result, the solution presented herein enables a receiver (100) to more accurately target the gain control such that the antenna elements (112) and associated receiver circuitry (110) most likely to be impacted by unwanted signals have a reduced gain, while the antenna elements (112) and associated receiver circuitry (110) less likely to be impacted by unwanted signals can operate with a higher gain.

Abstract: A mobile station in a spread spectrum communications system includes a matched filter that can be divided into segments. On initial acquisition, when a frequency deviation between the expected receiving frequency of the mobile station and the transmitting frequency of the base station is expected to be relatively large, the device can operate in a first synchronisation mode, in which the filter is used divided into segments. On searching for alternative cells, when the frequency deviation is expected to be smaller, the device can operate in a second synchronisation mode, in which the filter is used undivided. Thus, in the first mode, a reduced filter length avoids the difficulties caused by frequency deviation, while, in the second mode, an increased filter length allows faster acquisition.

Abstract: In a Class-D Amplifier with PCM (Pulse Code Modulated) input signal, the output pulse width may be adjusted to provide a constant time-voltage-area or the output pulse width may have one of several discrete values to provide a multi-level output system. A fundamental idea of this disclosure is to assure the center of each output pulse is always positioned at the nominal clock or with a fixed delay relative to the nominal clock. Said Class-D Amplifier typically converts the input signal into PDM (Pulse Density Modulated) pulses with a Sigma Delta Modulator and typically drives the output load with an H-Bridge.

Abstract: A method to linearize the characteristic of a Class-D amplifier is achieved, by compensating for the pulse-area-error, caused by a non-constant power-supply and similar circuit inconsistencies. A Class-D Amplifier typically converts the PDM (Pulse Density Modulated) input signal with a Sigma Delta Modulator and typically uses an H-Bridge as the Class-D power output stage. A fundamental idea is to keep the time-voltage area of every pulse constant. To achieve this, the circuit integrates the power supply voltage, starting with the PDM input pulse and stopping, when the defined time-voltage reference is reached. To compensate not only for power supply variations, but also for e.g. the voltage drop across the output devices, the integrator's input would be more directly reference to the actual voltage across the output load.

Abstract: In a Class-D Amplifier with PCM (Pulse Code Modulated) input signal, the output pulse width may be adjusted to provide a constant time-voltage-area or the output pulse width may have one of several discrete values to provide a multi-level output system. A fundamental idea of this disclosure is to assure the center of each output pulse is always positioned at the nominal clock or with a fixed delay relative to the nominal clock. Said Class-D Amplifier typically converts the input signal into PDM (Pulse Density Modulated) pulses with a Sigma Delta Modulator and typically drives the output load with an H-Bridge.

Abstract: A method to linearize the characteristic of a Class-D amplifier is achieved, by compensating for the pulse-area-error, caused by a non-constant power-supply and similar circuit inconsistencies. A Class-D Amplifier typically converts the PDM (Pulse Density Modulated) input signal with a Sigma Delta Modulator and typically uses an H-Bridge as the Class-D power output stage. A fundamental idea is to keep the time-voltage area of every pulse constant. To achieve this, the circuit integrates the power supply voltage, starting with the PDM input pulse and stopping, when the defined time-voltage reference is reached. To compensate not only for power supply variations, but also for e.g. the voltage drop across the output devices, the integrator's input would be more directly referenced to the actual voltage across the output load.

Abstract: The present invention relates to a spread spectrum communications system, in which a mobile station includes a matched filter which can be divided into segments.