Abstract: A symbol-level adaptation method to adapt at least one coefficient of an equalizer, the method comprising the steps of: a) executing an adaptive algorithm that calculates the value of the equalizer coefficient, the adaptive algorithm having a tunable parameter that determines how close the calculated coefficient value is to the optimal solution, b) modifying the value of the equalizer coefficient according to the calculated coefficient value at an intermediate instant t? strictly between two consecutive instants tA and tB, instants tA and tB corresponding to the beginning and the end of a pilot symbol period, respectively, and c) adjusting the value of the tunable parameter according to a number ? representing the number of chips yet to be received before instant tB or already received since instant tA.

Abstract: The invention is directed towards a method and apparatus for estimating a noise variance in a receiver of a code multiplex telecommunications system with orthogonal spreading codes, wherein respective real and imaginary parts of a sum and a difference of two estimated symbols having substantially same amplitudes are determined, and then respective minimum energy components of the determined real and imaginary parts of the sum and difference are determined. The respective minimum energy components are finally combined to obtain the noise variance. Thereby, noise variance can be estimated simply based on addition and comparison operations, which reduces complexity and processing load.

Abstract: The present invention relates to a receiver apparatus and method of channel estimation in a telecommunication system which provides at least two pilot sequences, and to a computer program product. Channel estimation is achieved by estimating channel taps separately for each of the at least two pilot sequences in every transmission block, and for applying estimated channel taps obtained from the estimation to at least one of a temporal and spatial filtering or combining operation to refine the channel estimate. Accordingly, temporal correlations and cross-correlations of the at least two pilot sequences are exploited without requiring knowledge of path delays and beamforming parameters.

Abstract: A symbol-level adaptation method to adapt at least one coefficient of an equalizer, wherein the method comprises the steps of: a) determining (144) if there exists a shortened pilot channelization code which has a spreading factor shorter than the spreading factor of a full pilot channelization code and which is, at the same time, still orthogonal to any other simultaneously active channelization codes, and, b) if there exists a shortened pilot channelization code, despreading (162) the pilot channel using the shortened pilot channelization code to obtain a pilot symbol estimation, and c) adapting (168) the value of the equalizer coefficient according to the error between the pilot symbol estimation obtained from step b) and a corresponding expected pilot symbol.

Abstract: A filter weight estimation device (D), for an equaliser of a communication receiver, comprises i) a tap delay line connected to N branches each comprising a descrambler (DS1-DSN) and a despreader (DE1-DEN), for despreading received signals, corresponding to one or more available multiplexed channels associated with different channelization codes, with a reference code equal to the sum of all the channelization codes associated to the available multiplexed channels, Ë) an adaptive filter (AF) comprising N input filter taps respectively connected to the N branches and a regression input and arranged to estimate the sum of the symbols outputted by the despreaders (DE1-DEN) and associated to each available channel, said symbol sum constituting a pseudo-symbol estimate defining a reference symbol estimate (rs), and to implement a mechanism of a LMS type to deliver a chosen number of filter weights (fi), iË) a quantiser (SM) arranged to quantise the reference symbol estimate (rs) to estimate a desired reference sym

Abstract: A method for deriving a channel transfer function from an Orthogonal Frequency-Division Multiplex (OFDM) signal received over a channel and having unmodulated sub-carriers and sub-carriers modulated with symbols, includes the steps of sampling the received OFDM signal at a sampling rate greater than the bandwidth of the OFDM signal, deriving from the sampled OFDM signal a set of time domain coefficients representative of the channel impulse response, and deriving from a subset of the set of time domain coefficients a channel transfer function in the frequency domain.

Abstract: The invention is directed towards a method and apparatus for estimating a noise variance in a receiver of a code multiplex telecommunications system with orthogonal spreading codes, wherein respective real and imaginary parts of a sum and a difference of two estimated symbols having substantially same amplitudes are determined, and then respective minimum energy components of the determined real and imaginary parts of the sum and difference are determined. The respective minimum energy components are finally combined to obtain the noise variance. Thereby, noise variance can be estimated simply based on addition and comparison operations, which reduces complexity and processing load.

Abstract: The present invention relates to a receiver apparatus and method of channel estimation in a telecommunication system which provides at least two pilot sequences, and to a computer program product. Channel estimation is achieved by estimating channel taps separately for each of the at least two pilot sequences in every transmission block, and for applying estimated channel taps obtained from the estimation to at least one of a temporal and spatial filtering or combining operation to refine the channel estimate. Accordingly, temporal correlations and cross-correlations of the at least two pilot sequences are exploited without requiring knowledge of path delays and beamforming parameters.

Abstract: A symbol-level adaptation method to adapt at least one coefficient of an equalizer, wherein the method includes a) determining if there exists a shortened pilot channelization code which has a spreading factor shorter than the spreading factor of a full pilot channelization code and which is, at the same time, still orthogonal to any other simultaneously active channelization codes, and, b) if there exists a shortened pilot channelization code, despreading the pilot channel using the shortened pilot channelization code to obtain a pilot symbol estimation, and c) adapting the value of the equalizer coefficient according to the error between the pilot symbol estimation obtained from step b) and a corresponding expected pilot symbol.

Abstract: The present invention relates to a method and a device for detecting active spreading codes for a signal in a communication system and estimating power of the active spreading codes. Further, the present invention ensures efficient interference cancellation. Multiple correlations are performed at a single level of a spreading code tree, the produced output samples are then observed at this level during a defined period, and a decision for the activity and power is met for all existing codes via extracting and processing information from these samples. At the correlation step, unitary fast Walsh Hadamard transformation is performed at practically the highest spreading factor in the system.

Abstract: The present invention relates to receiver apparatuses and methods of controlling weight adaptation in a receiver of a code multiplex telecommunications system with orthogonal spreading codes, wherein received discrete time signal samples are chip-level filtered by using a first equalising step. Additionally, the received discrete time signal samples are delayed by a time period corresponding to a data symbol and used in a second equalising step. Symbol estimates obtained from the first equalising step are non-linearly filtered and used as a desired response for the second equalising step in the following symbol period, wherein equaliser weights adapted in the second equalising step are used for the first equalising step. Alternatively, the second equalising step may be dispensed with and weight adaptation may be incorporated in a single equalising step.

Abstract: A filter weight estimation device (D), for an equaliser of a communication receiver, comprises i) a tap delay line connected to N branches each comprising a descrambler (DS1-DSN) and a despreader (DE1-DEN), for despreading received signals, corresponding to one or more available multiplexed channels associated with different channelization codes, with a reference code equal to the sum of all the channelization codes associated to the available multiplexed channels, Ë) an adaptive filter (AF) comprising N input filter taps respectively connected to the N branches and a regression input and arranged to estimate the sum of the symbols outputted by the despreaders (DE1-DEN) and associated to each available channel, said symbol sum constituting a pseudo-symbol estimate defining a reference symbol estimate (rs), and to implement a mechanism of a LMS type to deliver a chosen number of filter weights (fi), iË) a quantiser (SM) arranged to quantise the reference symbol estimate (rs) to estimate a desired reference sym

Abstract: A symbol-level adaptation method to adapt at least one coefficient of an equalizer, wherein the method comprises the steps of: a) executing an adaptive algorithm that calculates the value of the equalizer coefficient, the adaptive algorithm having a tunable parameter that determines how the calculated coefficient value is close to the optimal solution b) modifying the value of the equalizer coefficient according to the calculated coefficient value at an intermediate instant t? strictly between two consecutive instants tA and tB, instants tA and tB corresponding to the beginning and the end of a pilot symbol period respectively, and c) adjusting the value of the tunable parameter according to a number ? representing the number of chips yet to be received before instant tB or already received since instant tA.