Abstract:
An interference suppression scheme is provided for a radio receiver. According to the provided interference suppression scheme, the bandwidth of a received pilot signal and a data signal is divided into a plurality of frequency sub-bands. The pilot signal and the data signal have been transmitted according to single carrier data transmission technology. Interference parameters are calculated for each frequency sub-band separately. Interference suppression may be carried out jointly or separately for each frequency sub-band. After the interference suppression, the frequency sub-bands are combined. A filter bank may be used for dividing the total frequency band into sub-bands.
Abstract:
The invention provides a data transmission solution in a telecommunication system. According to the invention, a data transmission scheme is selected for a first transceiver unit, which comprises a plurality of transmit antennas, on the basis of the quality of a communication link and transmit antenna correlation information associated with the first transceiver unit, from a list including at least the following data transmission schemes: transmitting different data from each antenna of the first transceiver unit, the data transmitted from one antenna being independent of the data transmitted from another antenna; and transmitting the same data from each antenna of the first transceiver unit and controlling the direction of the transmitted data according to the properties of a radio channel. The selection of the data transmission scheme is carried out during an active communication link between the first and a second transceiver unit.
Abstract:
The invention relates to uplink communication in a GSM/EDGE telecommunication system. In the method according to the invention, at least one wide-band carrier wave in the group of carrier waves is generated in the mobile station by applying linear modulation at a second modulation symbol rate, the second modulation symbol rate being a multiple of the first modulation symbol rate, while preserving the predefined carrier spacing and allowing the at least one wide-band carrier wave to overlap with at least one adjacent carrier wave.
Abstract:
The present invention proposes a device for processing received signals (y) having been transmitted via a transmission channel (1), comprising: estimation means (2, 2a) adapted to obtain an estimated impulse response function (hk) of said channel (1) based on said received signals (y) which are received at a first time; derivation means (3; 3a-3f) adapted to derive history information (wink) based on at least one previously estimated impulse response function, calculation means (4; 4a, 4b) adapted to calculate modifying information (mwink) on the basis of said history information (wink), and modification means (5) adapted to modify said estimated impulse response function (hk) of said channel (1) obtained on the basis of said received signals (y), by applying said modifying information (mwink) to said estimated impulse response function (hk) of said channel obtained on the basis of said received signals (y), and adapted to output a modified impulse response function (hmk). The present invention also proposes a corresponding method.
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 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. In addition, the transmitter includes means for combining the weighted signals, after which the converter means converts the combined signal into an analog signal, and means for scaling the signal converted into the analog signal into a predetermined power level.
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.
Abstract:
A method for estimating an impulse response and a receiver in a radio system where the signal to be sent comprises a known training sequence, which receiver comprises means for sampling the received signal, and means for calculating a first estimate for the impulse response by means of the known training sequence. To enable an accurate determination of impulse response, the receiver comprises means for making preliminary decisions of the received samples by means of the first impulse response estimate, means for calculating an error value of the estimated samples and the received samples calculated by means of the preliminary decisions, means for calculating a second estimate of the impulse response by minimizing said error value, and means for calculating a new estimate for the impulse response by combining the first and second estimates to one another.
Abstract:
The invention relates to a decimation method and a decimation filter, which provide the transfer function of a CIC decimation filter. Decimation of the number of order N is performed by coefficient M, whereby FIR filtering is carried out in the main branch (100) of the decimation filter by M-tap FIR filters (20) N times in sequence, decimation is carried out by decimation means (21) by coefficient M and comb-filtering is carried out by means (22) N−1 times. The effect of sample cycles M preceding the sample cycle M to be processed is taken into account by using side branches (101, 102, 104) and additional branches (103, 105, 106, 107).
Abstract:
Many digital processors have an asynchronous bus controlled by two control signals. To interface a synchronous memory to an asynchronous bus, interface logic is required. In an interface for transferring data from an asynchronous circuit to a synchronous circuit, data to be written are written in an intermediate register while timing control signals are being synchronized to a system clock by means of flip-flops. Correspondingly, in an interface for transferring data from the synchronous circuit to the asynchronous circuit, a signal indicating a read transaction from the synchronous circuit is synchronized to the system clock by means of a flip-flop circuit.