Abstract: The invention relates to a method for parameter estimation in a digital radio system receiver, and a receiver. The receiver comprises a detector generating a number describing the probability of a received symbol using soft decision metrics. Mean values of the numbers describing the received symbol probability by which an estimator generates a new channel estimate are generated. As the energy of different symbols varies the channel estimate to be generated is weighted by the symbol energy to be generated. The channel estimate change can be attenuated by averaging or by multiplying the change by a weighting value. The channel estimate of the invention can also be used in the estimation of other data communication parameters whereby, for example, the Doppler error can be corrected.

Abstract: The invention relates to a method for determining connection quality, and a receiver in a radio system, the receiver comprising means for decoding a received signal by the Viterbi method by means of a trellis diagram comprising a group of state points, and means for calculating state transition values for the two possible transitions in each point of the diagram. To determine advantageously the quality of the connection between a transmitter and the receiver, the inventive receiver comprises means for calculating, in each column of the trellis diagram, the maximum values for both the transitions of the points in the column, for determining the absolute value of the difference of the calculated maximum values, and means for estimating connection quality by utilizing said absolute value.

Abstract: The present invention proposes a method for processing signals in order to remove waveform distortion by using an equalizer, said method comprising the steps of receiving an incoming signal, preprocessing said incoming signal, estimating a channel impulse response from said received signal estimating a noise energy from said received signal, calculating filter taps by using said estimated channel impulse response and said noise energy, filtering said received signal by using said calculated filter taps by a feedforward filter means, and supplying said received signal to an equalizer means which comprises a feedback filter, to obtain a resulting signal by a decision in said equalizer means, wherein said estimated channel impulse response is partitioned into at least two parts, in said calculating step of the filter taps one of said parts of said channel impulse response being used for calculating filter taps in said calculating step of the filter taps by using a weight function.

Abstract: The invention relates to a method for reducing the effects of noise and to a receiver comprising at least one sampling means (12) for forming sample signals from a received signal. The receiver also comprises a whitening means (30) for converting the noise in the sample signals to white noise and digital filters (41, 42, 43, 44) for filtering the sample signals comprising white noise. The receiver further comprises a computation means (80) for computing filter tap coefficients from a sample signal. Further still, the receiver comprises summers (51, 52), each one of which is arranged to receive a filtered signal from at least one filter and to sum the signals received from the filters to produce first summed signals. The receiver also comprises a detector (60) for summing the first summed signals to produce the actual summed signal and for detecting the actual summed signal.

Abstract: The present invention is a method and a device for automatic gain control of a telecommunication receiver, in particular a multi-carrier receiver in a time division multiple access system, wherein the signal is processed in the receiver during predetermined time slots, wherein the gain of the signal is allowed to be increased between the time slots and to be decreased during an actual time slot.

Abstract: The invention relates to a data transmission method and radio system. In particular, the invention relates to a method and system in which both the GMSK and the m-PSK modulation methods are available for the signal to be transmitted an in which the modulation method used at a given time can be changed to another modulation method. In the solution of the invention, the m-PSK modulator of the transmitter includes a multiplier adapted to multiply the signal to be transmitted by a given coefficient making the signal constellations of the received signal similar regardless of the modulation method. Thus, the processing of the signal in the receiver becomes easier and the quality of the transmission improves in connection with m-PSK modulation.

Abstract: A method for restricting a signal in a radio transmitter, which method comprises setting a threshold value and a value sample interval for the signal, searching the modulated signal for maximum values exceeding the threshold value, and determining the instant of occurrence of the maximum value that exceeded the threshold value, searching the modulated signal for additional sample values exceeding the threshold value at a distance of one or more value sample intervals from the moment of occurrence of at least one maximum value, forming, by means of the maximum values and additional sample values that were searched for, a signal that represents the part of the modulated signal that exceeds the threshold value, and subtracting from the modulated signal the formed signal representing the part that exceeds the threshold value.

Abstract: The invention relates to a method and arrangement for connecting a processor to an ASIC. In the arrangement, the processor generates control signals employed when the processor reads data from and writes data to the ASIC. The arrangement comprises means (10) for receiving control signals from the processor and generating read and write signals on the basis of the received signals. The means (10) are implemented by an asynchronous state machine that changes its state on the basis of the received signals. The means (10) change their state without a synchronizing clock signal.

Abstract: The invention relates to a filtering method and a filter implementing the filtering method. In the solution, a signal is filtered by at least one real FIR filter having at least one stop frequency pair whose different frequencies are symmetrically on different sides of at least one alias frequency.

Abstract: The present invention proposes a signal processing device for processing received signals having been transmitted via a transmission channel, wherein said received signals (y) are supplied to an estimation means (2) adapted to estimated a channel impulse response function (h) of said transmission channel (1), with said estimation means being adapted to perform a Linear-Minimum-Mean-Square-Error-(LMMSE-) processing based on a training sequence (TR_SEQ) transmitted together with received samples contained in said received signals (y), and a noise and interference energy estimate represented by a noise and interference variance (&dgr;2) as well as an impulse response energy distribution estimate represented by an estimated parameter covariance matrix (Chh) for said channel (1). The present invention also proposes a corresponding method for signal processing.

Abstract: In a mobile communication system, signals which are transmitted from mobile stations moving relative to a base station are subject to a Doppler effect. A technique is described for compensating for that Doppler effect by using estimated bit decisions for received bits which are sufficiently close to a zero phase offset point so as not to have been corrupted by the Doppler effect. The Doppler shift measured using these estimated bits can then be applied to bits of the signal which are further away from the zero phase offset point.

Abstract: The invention relates to a reception method and a receiver. Mechanisms are used for generating, at each level, numbers relating to a bit 1 and a bit 2 and representing a probability of a transition metric of survivor paths. Mechanisms are used for separately summing the numbers relating to the bit 1 and the bit 0 of more than one state and representing the probability of the transition metric. Mechanisms are used for generating logarithms of the sums and means for generating a difference of the logic numbers relating to the bit 1 and the bit 0 representing the probability of the transition metric, whereby a received bit can be determined without a correct path tracing phase.

Abstract: The invention relates to a method for determining connection quality, and a receiver in a radio system, the receiver comprising means for decoding a received signal by the Viterbi method by means of a trellis diagram comprising a group of state points, and means for calculating state transition values for the two possible transitions in each point of the diagram. To determine advantageously the quality of the connection between a transmitter and the receiver, the inventive receiver comprises means for calculating, in each column of the trellis diagram, the maximum values for both the transitions of the points in the column, for determining the absolute value of the difference of the calculated maximum values, and means for estimating connection quality by utilizing said absolute value.

Abstract: The invention relates to a filtering method and a filter implementing the filtering method. In the solution, a signal is filtered by at least one real FIR filter having at least one stop frequency pair whose different frequencies are symmetrically on different sides of at least one alias frequency.

Abstract: In a method for performing a phase comparison, and a phase comparator, two binary signals are compared using two functionally similar asynchronous state machines, which generate two output signals used for controlling a phase. A first state machine is fed a first signal to be compared, an output signal of a second state machine and a handshaking signal of the second state machine. The second state machine is fed a second signal to be compared, an output signal of the first state machine and a handshaking signal of the first state machine. The two state machines activate their respective handshaking signals after detecting activation of the signal to be compared. The handshaking signal ensures the logical operation of the phase comparator.

Abstract: The invention relates to a method of optimizing transmission, and a transmitter receiving digital signals, in which the transmitter is used in a radio system to optimally transmit the signals. The transmitter includes modulation means arranged to modulate the received signals, and converter means for converting the digital signal into an analog signal before signal transmission. The position of the signal received by the converter means within the dynamic range of the converter means affects optimality of the signal obtained from the conversion. The transmitter further include means for generating weighting coefficients, and means for weighting each modulated signal by a specific weighting coefficient so as to set the mutual power levels of the signals into predetermined relations and to optimally dispose the signals within the dynamic range of the converter means.

Abstract: The invention relates to a data transmission system between two transceivers, comprising: dividing the symbols to be transmitted into blocks, the number of which is divisible by the number of transmitting antennas; transmitting one block using each antenna; receiving the blocks using one or more antennas; checking whether the blocks were received successfully; and, if the reception of the blocks failed, storing the received blocks in memory; retransmitting the same blocks in a predetermined format; receiving the retransmitted blocks and combining them with the blocks in memory, the predetermined format being selected in the method so that the blocks transmitted first and the retransmitted blocks form space-time block coding.

Abstract: The present invention proposes a device (1) for processing received signals transmitted via a transmission channel (4), said device comprising obtaining means (2a) adapted to obtain an estimated response function (h+e) of said transmission channel (4), based on said received signals (y); deriving means (2b) adapted to derive and estimated variance (&dgr;2) of said received signals (y); and modifying means (2c) adapted to modify said estimated response function (h+e) by applying said estimated variance (&bgr;2) to said estimated response function (h+e), thereby obtaining a modified impulse response (h). The present invention also proposes a corresponding method.

Abstract: The invention relates to a method for estimating the quality of a connection and a diversity combination method in a digital radio system in which the signals transmitted are in burst form, the bursts comprising a training sequence; and to a receiver comprising a filter matched to the received signal. To effect simple estimation of the quality of the connection, the receiver comprises means for forming a result vector of at most the length of the training sequence from the symbols of the output signal of the matched filter and the corresponding symbols of the training sequence; means for computing a mean value and variance for the symbols of the result vector; and means for forming a quantity proportional to signal quality as a quotient of the squared mean value of the result vector and the variance of the result vector.

Abstract: The invention relates to a method and an apparatus for implementing automatic gain control in a system where an analog signal is converted into a digital signal. The apparatus comprises means (208) for performing automatic gain control of the adjustable signal in an analog manner using a gain control step of predetermined size and means (446, 448) for performing inverse gain control of the digitized signal in such a way that, after the digital adjustment, the power of the signal is the same as before the analog adjustment. To enable an accurate gain control, the apparatus further comprises means (410, 412, 214, 420) for determining the maximum energy of the signal during a predetermined measurement period, means (426, 428) for comparing the determined maximum energy to preset threshold values (430, 432), and means (436) for performing an automatic gain control of the analog signal and a compensation for the gain control to the digital signal, if the measured value exceeds the threshold.