US 4,731,801 AGranted

Method for the reception and detection of digital signals

AssigneeNokia Corporation

InventorJukka Henriksson

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Abstract

Described herein is a method for the reception and the detection of digital signals. According to the method at least two signals (s.sub.1, s.sub.2, . . . , s.sub.M) having at least approximately the same information content are received and out of each received signal (S.sub.i) is generated by means of a phase shift one in-phase baseband signal (s.sub.iI) and one quadrature baseband signal (s.sub.iQ). All in-phase baseband signals (s.sub.iI) are summed in a first summing point (3a) and all quadrature baseband signals (s.sub.iQ) in a second summing point (3b), both sum signals (y.sub.Ik and y.sub.Qk) are fed to a detector (4) for detection and generating two detected output signals (s.sub.Ik and s.sub.Qk), and a reference carrier (ca) is generated as a function of said two sum signals (y.sub.Ik and y.sub.Qk) for carrying out a coherent demodulation. According to the invention a projection voltage (z.sub.k) defined by the equation z.sub.k =y.sub.Qk s.sub.Ik -y.sub.Ik s.sub. Qk is generated, wherein y.sub.Ik is a signal sample in the in-phase branch before threshold decision in the detector, y.sub.Qk is the signal sample in the quadrature branch before decision, s.sub.Ik is the detected signal in the in-phase branch, and s.sub.Qk is the detected signal in the quadrature branch.

Claims11

Dependent claims

A method for the reception and the detection of digital signals, comprising:

receiving at least two signals (s.sub.1, s.sub.2, . . . , s.sub.M) having at least approximately the same information content, by means of at least one antenna or equivalent,
generating out of each received signal (s.sub.i), by means of a phase shift, and a demodulation, one in-phase baseband signal (s.sub.iI) and one quadrature baseband signal (s.sub.iQ),
summing all in-phase baseband signals (s.sub.iI) in a first summing point and all quadrature baseband signals (s.sub.iQ) in a second summing point,
feeding both sum signals (y.sub.Ik and y.sub.Qk) to a detector (4) for detection and generating two detected output signals (s.sub.Ik and s.sub.Qk), and
generating a reference carrier (ca) as a function of said two sum signals (y.sub.Ik and y.sub.Qk) for carrying out a coherent demodulation,
characterized by
generating a projection voltage (z.sub.k) defined by the following equation
z.sub.k =y.sub.Qk s.sub.Ik -y.sub.Ik s.sub.Qk,
wherein
y.sub.Ik is a signal sample in the in-phase branch before threshold decision in the detector,
y.sub.Qk is the signal sample in the quadrature branch before decision,
s.sub.Ik is the detected signal in the in-phase branch, and
s.sub.Qk is the detected signal in the quadrature branch,
generating a product signal (b) by multiplying the projection voltage (z.sub.k) with a signal (r) being a function of said sum signals (y.sub.Ik and y.sub.Qk),
generating control voltages (c.sub.1, . . . , c.sub.M) by correlating said product signal (b) with each received signal (s.sub.1, . . . , s.sub.M), by means of correlators (Cor.sub.1, . . . , Cor.sub.M), and
controlling the phase shifts by means of said control voltages (c.sub.1, . . . , c.sub.M).

13 more elements

Dependencies are inferred from the claim text.