Telefonaktiebolaget Lm Ericsson (publ)

H&aring;kan Eriksson

Torgny Palenius

Kjell Berthold Gustafsson

Roozbeh Atarius

Christer &Ouml;stberg

Paul Wilkinson Dent

Sven Erik Mattisson

Torsten John Carlsson

Sven Harald Ekemark

Kenzo Urabe

Magnus L Berg

Martin J Jonson

Lars-G&ouml;ran Lund

H&aring;kan Henningsson

Direct frequency modulation of a phase-locked loop (PLL) output signal is achieved by means of a modulation signal comprising a digital sequence. The digital modulation signal is coupled to the input of the VCO of the PLL, and is also coupled to drive an up-down counter. The output of the counter is coupled to a D/A converter to provide a compensation signal for the PLL. When the counter output reaches values representing modulation-induced phase errors of &plus;360 degrees and &minus;360 degrees, the counter generates signals respectively corresponding thereto to adjust the PLL frequency divider.

Direct modulated phase-locked loop

A first searcher searches a first channel (e.g., a broadcast channel), a second searcher searches a second channel (e.g., a traffic channel), and the second searcher uses information from the first searcher to search the second channel. In one aspect of the invention, the first searcher generates a delay profile for the first channel. A second searcher uses the delay profile to generate a set of taps for the second channel. In another aspect of the invention, the first searcher is configured to find a maximum correlation value (or a set of maximum correlation values). The second searcher shifts a search finger by an amount equal to the delay corresponding to the maximum correlation value(s). The second searcher can also shift a code corresponding to the second signal by an amount equal to the sum of the delay corresponding to the maximum correlation value(s) and a predetermined value.

Method and apparatus for configuring a RAKE receiver

In a radio network which employs adaptive antennas for transmission of data to mobiles methods and apparatus are provided for improving the reception of transmitted data. When a block is to be transmitted in a first beam of the antenna and the block contains information for the mobile in the second beam, a modulation and coding scheme is used for the transmission of the block such that the modulation and coding scheme provides greater protection to the portion of the block containing information for the mobile in the second beam. The use of greater protection for the portion of the block which includes information for the mobile in the second beam increases the probability that the mobile in the second beam can receive and correctly decode the information intended for the mobile in the second beam in the block.

Compensation for antenna diagram optimization

A receiver having a digital automatic gain control (AGC) circuit is disclosed for use in a cellular communication system, including a Hierarchical Cellular System. The receiver includes a controller which switches between gain control values depending on system operational mode. In this way, the AGC can be optimized for different types of receive processing operations, e.g., traffic reception and measurement of other channels.

Automatic gain control for slotted mode operation

A receiver can identify the source of a signal from an unsynchronized source. The receiver has an antenna for receiving two signals. The receiver correlates the first signal with a code to find a first location in time, and correlates the second signal with the same code to find a second location in time. The receiver calculates a time difference between the first location in time and the second location in time and uses the time difference to identify the source of the two signals. A group of base stations or directional antennas use the same long code and synchronization codes. However, each source shifts the long code by a different amount so that for any two sources there is a unique difference between the shifts in the long code. Each source shifts a set of synchronization codes the same amount as the long code. The synchronization codes can be any short code that is relatively easy for the mobile station to detect. When the receiver receives the two signals, the receiver calculates the difference in the shifts. Because there is a unique difference for each pair of sources, the receiver can identify the source of a signal from an unsynchronized source without having to connect to the source to use a broadcast channel or control channel. The receiver can distinguish between different synchronized sources without any prior synchronization.

Method and apparatus for identifying the source of a digital signal

The present invention provides a system and method for reducing the power consumed by a RAKE receiver. In exemplary embodiments of the present invention, an environment variation estimator is implemented in a CDMA mobile station. The environment variation estimator is connected to the searcher of the RAKE receiver and provides an estimate of the rate at which the mobile station's environment is changing. By providing an estimate of the rate of change of the mobile station's environment, the duty cycle of the searcher can be optimized, thereby reducing the overall power consumed by the receiver. By also providing the estimate to the RAKE fingers, channel tracking can be improved.

Motion estimator for a CDMA mobile station

A transmitter in a radiocommunications system such as a Wideband Code Division Multiple Access (WCDMA) communications system transmits one set of data on an in-phase (I-) channel and another set of data on a quadrature (Q-) channel. The transmitter generates a gain signal, &bgr;, and multiplies the digital data associated with the Q-channel by the gain signal, &bgr;. Complexity of the multiplication operation is reduced by limiting the gain signal, &bgr;, to a finite number of values that are exactly representable by a predefined number of bits, such as 4-bit values to the right of a binary radix point. Modulation inaccuracy associated with quantization of &bgr; can be eliminated by utilizing the same quantized values of &bgr; in all components within the radiocommunications system.

Growing community of inventors

Lund, Sweden

Håkan Eriksson

Growing community of inventors

Lund, Sweden

H&aring;kan Eriksson

Håkan Eriksson