Method and rake receiver for phasor estimation in communication systems
First Claim
1. A method for phasor estimation in CDMA communication systems comprising a) receiving an electromagnetic signal being a superposition of a plurality of signal components of different signal propagation paths, b) digitising the received signal, c) distributing the digitised signal to fingers of a RAKE receiver, wherein at least a first one of the fingers is assigned to a first one of the signal propagation paths, d) decorrelating the digitised signal by a code sequence in a detection stream of the RAKE receiver, e) estimating the interference of a first signal component assigned to the first signal path (i) with a second signal component assigned to a second one of the signal paths (j,j≠
- i) and f) estimating the phasor of the first signal component (i).
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Abstract
The invention relates to a channel estimation algorithm is proposed for a RAKE receiver for CDMA communication systems operating in the downlink of a mobile communication scenario yielding an improved phasor estimation. Received signals are distributed to a plurality of receiver fingers of a RAKE receiver. Each receiver finger i is assigned to a signal path of the transmitted signal which is subject to phase shift and power dissipation due to reflection, diffraction and scattering. According to the invention the approach partly cancels multipath/multiuser interference and offers the advantage of being able to cope with physically closely spaced multipaths.
87 Citations
14 Claims
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1. A method for phasor estimation in CDMA communication systems comprising
a) receiving an electromagnetic signal being a superposition of a plurality of signal components of different signal propagation paths, b) digitising the received signal, c) distributing the digitised signal to fingers of a RAKE receiver, wherein at least a first one of the fingers is assigned to a first one of the signal propagation paths, d) decorrelating the digitised signal by a code sequence in a detection stream of the RAKE receiver, e) estimating the interference of a first signal component assigned to the first signal path (i) with a second signal component assigned to a second one of the signal paths (j,j≠ - i) and
f) estimating the phasor of the first signal component (i). - View Dependent Claims (2, 3, 4, 5, 6, 8, 9)
- i) and
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7. A method according to claim l, wherein the digitised signal is distributed to the detection stream and a synchronising stream before the decorrelation takes place.
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10. A RAKE receiver for processing a received electromagnetic signal being a superposition of signal components of different signal propagation paths, comprising
a plurality of receiver fingers, wherein at least a first one of the receiver fingers is adapted to receive a first signal component assigned to a first one of the signal paths (i), a correlator for decorrelation of the digitised signal by a code sequence, an device for estimation of interference between the first signal component with a second signal component assigned to a second of the signal paths (j,j≠ - I) and
a device for phasor estimation of the first signal component (i). - View Dependent Claims (11, 12, 13, 14)
- I) and
Specification