RAKE receiver

A RAKE receiver, comprising:

• at least two antenna branches (232A, 232B) for receiving a radio signal;
• at least one RAKE finger (270A, 270B) connected to the antenna branches (232A, 232B) for processing a multipath propagated signal component of the radio signal;
• a delay estimator (260) connected to the antenna branches (232A, 232B) for searching for a delay of at least one multipath propagated signal component and for allocating a RAKE finger (270A, 270B) for processing the found multipath propagated signal component and for informing said RAKE finger (270A, 270B) of the found delay;
• the RAKE finger comprising:
• a channel estimator (272) for generating an impulse response of the channel of the multipath propagated signal component found by means of a known pilot part included in the radio signal of each antenna branch (232A, 232B);
• an interference estimator (272) for generating an interference signal, included in the radio signal of each antenna branch (232A, 232B) and consisting of interference and noise, by subtracting from the received radio signal a regenerated wanted radio signal, which regenerated wanted radio signal is obtained by means of the known pilot part and the estimated impulse response of the channel;
• a despreader (276A, 276B) connected to each antenna branch (232A, 232B) for despreading the pilot part (274A) included in the multipath propagated signal component by using a known spreading code by a delay informed by the delay estimator (260);
• a despreader (276C, 276D) connected to each antenna branch (232A, 232B) for despreading the data part (274B) included in the multipath propagated signal component by using the known spreading code by a delay informed by the delay estimator (260),
• characterized in that the RAKE finger (270A, 270B) also comprises:
• a weighting coefficient part (272) for providing each antenna branch (232A, 232B) with weighting coefficients maximizing the Signal-to-Interference-and-Noise Ratio (SINR);
• a multiplier (284A, 284B) for multiplying the pilot part (274A), despread by the despreader (276A, 276B) in each antenna branch (232A, 232B), by a weighting coefficient;
• a multiplier (284C, 284D) for multiplying the data part (274B), despread by the despreader (276C, 276D) in each antenna branch (232A, 232B), by a weighting coefficient;
• an antenna branch summer (278A) for combining the despread pilot parts (274A), received via the separate antenna branches (232A, 232B) and multiplied by the weighting coefficient, to one pilot signal;
• an antenna branch summer (278B) for combining the despread data parts (274B), received via the separate antenna branches (232A, 232B) and multiplied by the weighting coefficient, to one data signal;
• and the RAKE receiver further comprises a RAKE finger summer (280B) for combining the data signals of the RAKE fingers (270A, 270B) operating by different delays to a sum data signal representing the received bits.