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US 6,674,792 B1Granted
Demodulation of receiver with simple structure
AssigneeNEC Corporation
InventorNaohiko Sugita
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AssigneeNEC Corporation
InventorNaohiko Sugita
Estimating the term…
A receiver includes inversely spreading circuit, a RAKE synthesizing circuit, a noise measuring circuit, a weighting circuit and a decoder. The inversely spreading circuit inversely spreads a reception signal for every path using a spreading code to produce path data signals for paths. The RAKE synthesizing circuit synthesizes the path data signals to output a RAKE synthesis signal while carrying out a weighting operation for every path such that the RAKE synthesis signal has a maximum S/N ratio. The noise measuring circuit measures a noise level of each of the path data signals, and calculates a total noise amount for the paths from the measured noise levels. The weighting circuit carries out a weighting operation of the RAKE synthesis signal based on the total noise amount to produce a weighted signal such that a time change of distortion in the RAKE synthesis signal is cancelled. The decoder decodes the weighted signal to produce an information sequence.
A receiver comprising:
A method of demodulating a received radio signal, comprising:
Dependencies are inferred from the claim text.
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No related US applications are recorded in the indexed filing history.
Constructive combining of multi-path signals, i.e. RAKE receivers: weighting of fingers for combining, e.g. amplitude control or phase rotation…
Transmission
Term ended 11 Jun 2022 (estimated)
USPTO file history isn’t available for this patent, so only indexed dates are shown.
1. Field of the Invention
The present invention relates to a demodulating method and a demodulating circuit in a radio receiver. More particularly, the present invention relates to a method and a circuit for demodulating a reception signal in which selective fading occurs on a transmission path.
2. Description of the Related Art
FIG. 1 is a block diagram showing the structure of an example of a conventional receiver;
FIGS. 2A and 2B are diagrams showing the format of data and a unique word;
FIG. 3 is a block diagram showing the structure of a receiver according to an embodiment of the present invention;
Hereinafter, a receiver of the present invention will be described with reference to the attached drawings.
FIG. 3 is a block diagram showing the structure of a demodulating circuit of the receiver according to an embodiment of the present invention. Referring to FIG. 3, the same components as those in FIG. 1 are allocated with the same reference numerals, respectively. The embodiment shows a demodulating circuit of a base station, for example. The demodulating circuit communicates with mobile terminals in a mobile communication system in which the mobile terminal communicates with a counter terminal through the base station and a network.
Referring to FIG. 3, a reception signal is supplied to a path searching circuit 11 and an inversely spreading circuit 12. The reception signal includes a unique word composed of a real part (I signal) of data and an imaginary part (Q signal) of a known fixed pattern, as shown in FIGS. 2A and 2B. Each of symbols of the I signal and the Q signal is spread over a plurality of chips with a spreading code. That is, the reception signal is a PSK modulation wave in which a frequency spectrum is spread with the spreading code.