Patent US2471983A successfully refreshed from Google Patents.
EP0806844A1
Expired / Lapsed
EP
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Diversity receiver and control method therefor
Assignee: NTT Docomo Inc
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Filing: 1996-11-28
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Granted: —
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Expires: 2016-11-28
Abstract
Abstract A weight coefficient is feedback-controlled so as to maximize the ratio of desired signal power to interference power (SIR), whereby it is possible to improve reception quality and to increase the number of subscribers per cell and it is also possible to increase the speed of establishment of diffused code synchronization and the speed of convergence of the weight coefficient. A coherence adaptive diversity arrangement to which absolute synchronization detection is applicable is adopted. The weighht coefficient of each diversity branch is adaptively feedback-controlled, whereby it is possible to reduce the influence of interference power from other communicators, so that the number of subscribers per cell can be increased. Furthermore, a direction in which a highest reception SIR is obtainable is determined by rotating an antenna with directivity of predetermined angle being given to it. After that, by setting the initial value of the weight coefficient to the direction, the speed of convergence of the weight coefficient can be increased.
Inventors
- 👤 Mamoru Sawahashi
- 👤 Hidehiro Ando
- 👤 Yoshinori Miki
- 👤 Kenichi Higuchi
- 👤 Shinya Tanaka
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-28 09:48
CPC Classifications
H; H04; H04B; H04B7/00; H04B7/02; H04B7/04; H04B7/08; H04B1/00; H04B1/69; H04B1/707; H04B1/709; H04B7/0837; H04B7/0842; H04B7/0848; H04B7/0851; H04B7/0857; H04B7/24; H04B7/26; H04L; H04L1/00; H04L1/02; H04L1/06; H04B1/7097; H04B1/711; H04B1/7115; H04B1/712; H04B7/086
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
92 words
A diversity receiver employing, when receiving a data signal transmitted in accordance with a direct sequence CDMA scheme, correlators for despreading, for respective branches, a plurality of fading received waves, and a plurality of multipliers for multiplying despread signals output from said correlators by weighted coefficients, said diversity receiver characterized by comprising: decision means for recovering said data signal; and weighted coefficient computing means for using decision error information obtained in response to an output signal and an input signal of said decision means as feedback information for controlling said weighted coefficients.
Claim 2
Dependent Claim
147 words
A diversity receiver for performing diversity reception of a data signal transmitted in accordance with a direct sequence CDMA scheme, said diversity receiver characterized by comprising: correlators for despreading, for respective branches, a plurality of fading received waves; a plurality of multipliers for multiplying despread signals output from said correlators by weighted coefficients; an adder for summing up weighted signals output from said plurality of multipliers; phase compensation means for compensating a signal output from said adder for phase fluctuations of fading received waves; decision means for recovering said data signal from a compensated signal output from said phase compensation means; subtraction means for computing error vector components corresponding to a difference between said data signal recovered and said compensated signal; and weighted coefficient generating means for generating said weighting coefficients in response to said phase fluctuations of said fading received signal and said error vector components.
Claim 3
Dependent Claim
42 words
The diversity receiver as claimed in claim 1 or 2, characterized in that said correlators are each disposed after RF signal processors provided for respective branches, and carry out correlation detection using a spreading signal sequence replica at a symbol information rate.
Claim 4
Dependent Claim
146 words
A diversity receiver characterized by comprising, for L multipaths, L sets of said correlators, said multipliers, said adder, said phase compensation means and said weighted coefficient generating means, and further characterized by comprising: RAKE combining means for combining phase compensated signals output from said phase compensation means corresponding to respective paths; decision means for recovering an incoming data signal by deciding an output of said RAKE combining means; error vector computing means for computing error vector components from an input signal and an output signal of said decision means, or from input signals to said RAKE combining means associated with respective paths and said output signal from said decision means; and feedback signal computing means for supplying said weighed coefficient generating means for respective paths with feedback decision information for computing said weighted coefficients from said error vector components and received phase components of individual paths.
Claim 5
Dependent Claim
36 words
The diversity receiver as claimed in claim 4, further characterized by comprising M sets of antennas and RF stages, characterized in that said diversity receiver in claim 4 is disposed in common after said RF stages.
Claim 6
Dependent Claim
157 words
A diversity receiver for performing mobile communications with a mobile station using a direct sequence CDMA scheme that carries out multiple access transmission by spreading a narrowband signal to a wideband signal using a spreading code with a rate higher than that of an information rate, said diversity receiver characterized by comprising: a plurality of receiving antennas for receiving a direct sequence spread signal sent from said mobile station, said receiving antennas being set in a directional state; spreading code synchronization establishing means for performing spreading code synchronization establishment which corresponds to despreading of an input signal to each of said plurality of receiving antennas; weighted coefficient multiplication means for multiplying weighted coefficients by signals obtained through despreading by said spreading code synchronization establishing means; signal combining means for combining signals after multiplications by said weighted coefficient multiplication means; and adaptive diversity reception control means for controlling said weighted coefficients such that a received SIR becomes maximum.
Claim 7
Dependent Claim
84 words
The diversity receiver as claimed in claim 6, further characterized by comprising: means for generating forward link transmission weighted coefficients from said weighted coefficients which are obtained by said adaptive diversity reception control means and maximize the received SIR, said forward link transmission weighted coefficients being used when carrying out transmission from said diversity receiver to said mobile station; and means for correcting said forward link transmission weighted coefficients using a reverse link control signal transmitted from said mobile station to said diversity receiver.
Claim 8
Dependent Claim
153 words
A diversity receiver control method for performing mobile communications between a mobile station and a diversity receiver using a direct sequence CDMA scheme that carries out multiple access transmission by spreading a narrowband signal to a wideband signal using a spreading code with a rate higher than that of an information rate, said diversity receiver control method characterized by comprising the steps of: receiving with a plurality of receiving antennas a direct sequence spread signal sent from said mobile station, said receiving antennas being set in a directional state; establishing spreading code synchronization which corresponds to despreading of an input signal to each of said plurality of receiving antennas; multiplying weighted coefficients by signals obtained through despreading in said step of establishing spreading code synchronization; combining signals after multiplications in said step of multiplying weighted coefficients; and controlling adaptive diversity reception by controlling said weighted coefficients such that a received SIR becomes maximum.
Claim 9
Dependent Claim
72 words
The diversity receiver control method as claimed in claim 8, characterized in that said step of receiving with a plurality of receiving antennas comprises a step of receiving the direct sequence spread signal sent from said mobile station with the antennas being set in non-directional state; and said step of controlling adaptive diversity reception comprises a step of setting initial values of said weighted coefficients at values corresponding to the non-directional state.
Claim 10
Dependent Claim
78 words
The diversity receiver control method as claimed in claim 8, characterized in that said step of receiving with a plurality of receiving antennas comprises a step of receiving the direct sequence spread signal sent from said mobile station with the antennas being set in non-directional state; and said step of controlling adaptive diversity reception comprises a step of setting initial values of said weighted coefficients at values obtained when said diversity receiver turns its gain to one direction.
Claim 11
Dependent Claim
134 words
The diversity receiver control method as claimed in claim 8, characterized in that said step of receiving with a plurality of receiving antennas comprises a step of receiving the direct sequence spread signal sent from said mobile station with the antennas being set in a state in which said diversity receiver has directivity in one direction with a predetermined angle range, and sets the directivity which provides maximum received SIR by measuring the received SIR one or more times while rotating the directivity of the antennas at predetermined intervals after the establishment of said spreading code synchronization; and said step of controlling adaptive diversity reception comprises a step of setting initial values of said weighted coefficients at values obtained when said diversity receiver turns its gain to the direction providing the maximum received SIR.
Claim 12
Dependent Claim
86 words
The diversity receiver control method as claimed in claim 8, further characterized by comprising the steps of: generating forward link transmission weighted coefficients from said weighted coefficients which are obtained in said step of controlling adaptive diversity reception, and maximize the received SIR, said forward link transmission weighted coefficients being used when carrying out transmission from said diversity receiver to said mobile station; and correcting said forward link transmission weighted coefficients using a reverse link control signal transmitted from said mobile station to said diversity receiver.
References Cited (Backward Citations)
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