Abstract: The present invention relates to methods and an apparatus for estimating a residual frequency error. According to an embodiment, an expected vector for selected subcarriers of a received symbol is estimated using a channel estimate vector and a reference vector; a sampling frequency mismatch is removed and a dot product is calculated using the expected and a received vector. An angle of the product is estimated and a change in angle from a previous symbol is calculated. The residual frequency is estimated using the calculated change in angle. In another embodiment, an expected subcarrier is estimated based on a channel estimate and on a reference subcarrier, an angle and magnitude of the multiplication between the expected and a received subcarrier are estimated; a phase offset is removed; a weighted mean value of the angles is calculated and the residual frequency error is estimated using a change in weighted mean angle.

Abstract: The present application relates to a method and an apparatus for synchronizing a receiver timing to a transmitter timing using a known preamble of a signal. In at least one embodiment of the method and/or the apparatus of the present application, a power normalized cross-correlation metric (PNCC metric) is estimated based on a signal power and a noise floor power. According to a first embodiment, two cross-correlation functions, one based on the PNCC metric and the other based on a cross-correlation metric, are used to decide if synchronization events occur and based on the analysis of time indexes and PNCC magnitude values, a timing synchronization index used to synchronize receiver timing to transmitter timing is determined. According to a second embodiment, the cross-correlation function based on the PNCC metric is used to decide if synchronization events occur and based on an analysis of time indexes and PNCC magnitude values using a clustering approach, a timing synchronization index is determined.

Abstract: Low complex algorithms for estimating a delay spread or a RMS delay spread of a multipath channel using channel estimates are disclosed, leading to low overall power consumption. According to an embodiment of the present invention, a delay spread or a RMS delay spread of the multipath channel is determined based on a metric calculated as a function of channel estimates. In another embodiment, an average signal to noise ratio is taken into consideration in addition to the metric to estimate the delay spread or the RMS delay spread. In a further embodiment, the delay spread or the RMS delay spread of the multipath channel is estimated based on an average signal to noise ratio and on a metric being a function of the slope between subcarrier channel estimates. The present invention further relates to an apparatus for estimating a delay spread or a RMS delay spread of the multipath channel.

Abstract: The present invention relates to methods and an apparatus for estimating a residual frequency error. According to an embodiment, an expected vector for selected subcarriers of a received symbol is estimated using a channel estimate vector and a reference vector; a sampling frequency mismatch is removed and a dot product is calculated using the expected and a received vector. An angle of the product is estimated and a change in angle from a previous symbol is calculated. The residual frequency is estimated using the calculated change in angle. In another embodiment, an expected subcarrier is estimated based on a channel estimate and on a reference subcarrier, an angle and magnitude of the multiplication between the expected and a received subcarrier are estimated; a phase offset is removed; a weighted mean value of the angles is calculated and the residual frequency error is estimated using a change in weighted mean angle.

Abstract: The present application relates to a method and an apparatus for synchronising a receiver timing to a transmitter timing using a known preamble of a signal. In at least one embodiment of the method and/or the apparatus of the present application, a power normalised cross-correlation metric (PNCC metric) is estimated based on a signal power and a noise floor power. According to a first embodiment, two cross-correlation functions, one based on the PNCC metric and the other based on a cross-correlation metric, are used to decide if synchronisation events occur and based on the analysis of time indexes and PNCC magnitude values, a timing synchronisation index used to synchronise receiver timing to transmitter timing is determined. According to a second embodiment, the cross-correlation function based on the PNCC metric is used to decide if synchronisation events occur and based on an analysis of time indexes and PNCC magnitude values using a clustering approach, a timing synchronisation index is determined.

Abstract: Low complex algorithms for estimating a delay spread or a RMS delay spread of a multipath channel using channel estimates are disclosed, leading to low overall power consumption. According to an embodiment of the present invention, a delay spread or a RMS delay spread of the multipath channel is determined based on a metric calculated as a function of channel estimates. In another embodiment, an average signal to noise ratio is taken into consideration in addition to the metric to estimate the delay spread or the RMS delay spread. In a further embodiment, the delay spread or the RMS delay spread of the multipath channel is estimated based on an average signal to noise ratio and on a metric being a function of the slope between subcarrier channel estimates. The present invention further relates to an apparatus for estimating a delay spread or a RMS delay spread of the multipath channel.

Abstract: A transmitter comprises a device (20) for frequency up-conversion of a communication signal having at least two consecutive frequency conversion stages, a power amplifier (27) for amplifying the output signal therefrom for obtaining a transmission signal and means (29) for extracting the transmission signal. It also has a device for frequency down-conversion of said extracted transmission signal to the same frequency as the communication signal before said up-conversion for creating a feedback signal. Said two devices use the same local oscillators (25, 26). The transmitter also has means for signal parameter adaptation of the communication signal on basis of the feedback signal for obtaining a desired character of the transmission signal.

Abstract: In a wireless telecommunications system, data processing delays associated with digital channelization and de-channelization may be reduced through the use of a technique that involves processing data blocks in conjunction with the transformation of the data blocks by a large, Fast Fourier Transform (FFT) algorithm, and makes use of multiple transmission and reception branches. In accordance with this technique, the processing delays associated with the FFT algorithm are minimized, but not to the detriment of other important channelizer/de-channelizer design characteristics, such as power consumption, die area and computational complexity.

Abstract: The invention provides robust and non-invasive calibration of an adaptive signal conditioning system having a signal conditioning block in the signal path to a signal conversion system, and a feedback path with a number of feedback components for enabling adaptation, by means of a parameter adaptation block, of the parameters used in the signal conditioning. In order to calibrate the feedback path, a well-defined reference signal is inserted into the feedback path, and an appropriate calibration coefficient is then determined by a coefficient calibrator in response to the received reference signal. The calibration coefficient is provided to a compensator, which effectively compensates for changes in the transfer characteristics of the feedback path due to factors such as variations in ambient temperature and component aging.

Abstract: The invention provides robust and non-invasive calibration of an adaptive signal conditioning system having a signal conditioning block in the signal path to a signal conversion system, and a feedback path with a number of feedback components for enabling adaptation, by means of a parameter adaptation block, of the parameters used in the signal conditioning. In order to calibrate the feedback path, a well-defined reference signal is inserted into the feedback path, and an appropriate calibration coefficient is then determined by a coefficient calibrator in response to the received reference signal. The calibration coefficient is provided to a compensator, which effectively compensates for changes in the transfer characteristics of the feedback path due to factors such as variations in ambient temperature and component aging.

Abstract: A transmitter comprises a device (20) for frequency up-conversion of a communication signal having at least two consecutive frequency conversion stages, a power amplifier (27) for amplifying the output signal therefrom for obtaining a transmission signal and means (29) for extracting the transmission signal. It also has a device for frequency down-conversion of said extracted transmission signal to the same frequency as the communication signal before said up-conversion for creating a feedback signal. Said two devices use the same local oscillators (25, 26). The transmitter also has means for signal parameter adaptation of the communication signal on basis of the feedback signal for obtaining a desired character of the transmission signal.

Abstract: The present invention increases the flexibility of the modified fast convolution algorithm. In a first exemplary embodiment of the present invention, a block compensator is inserted into the channelizer/de-channelizer processing chain for multiplying data in the processing chain with compensation constants. The block compensator corrects the phase continuity problem associated with the modified fast convolution algorithm to thereby allow unrestricted filter placement. In a second exemplary embodiment, the phase continuity problem is corrected by combining a frequency translation in the frequency domain with a compensatory frequency translation in the time domain. Both techniques increase the flexibility of the modified fast convolution algorithm whilst only marginally increasing computational requirements.

Abstract: The present invention increases the flexibility of the modified fast convolution algorithm. In a first exemplary embodiment of the present invention, a block compensator is inserted into the channelizer/de-channelizer processing chain for multiplying data in the processing chain with compensation constants. The block compensator corrects the phase continuity problem associated with the modified fast convolution algorithm to thereby allow unrestricted filter placement. In a second exemplary embodiment, the phase continuity problem is corrected by combining a frequency shift in the frequency domain with a compensatory frequency shift in the time domain. Both techniques increase the flexibility of the modified fast convolution algorithm whilst only marginally increasing computational requirements.

Abstract: The present invention increases the flexibility of the modified fast convolution algorithm. In a first exemplary embodiment of the present invention, a block compensator is inserted into the channelizer/de-channelizer processing chain for multiplying data in the processing chain with compensation constants. The block compensator corrects the phase continuity problem associated with the modified fast convolution algorithm to thereby allow unrestricted filter placement. In a second exemplary embodiment, the phase continuity problem is corrected by combining a frequency translation in the frequency domain with a compensatory frequency translation in the time domain. Both techniques increase the flexibility of the modified fast convolution algorithm whilst only marginally increasing computational requirements.