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US 7,116,998 B2Granted
Subtractive multipath delay detection
AssigneeTelefonaktiebolaget L M Ericsson (publ)
InventorsXiaohui Wang, Anders Ericsson
Life of this patent
Estimating the term…
Abstract
In a RAKE receiver delays associated with multipath signals are determined by subtracting power values associated with sidelobes of a peak value for each of the multipath signals. The determination can be performed in two stages, in the first stage the determination of the delays is made without accounting for a phase difference between adjacent multipath signals, while in the second stage the determinations are made accounting for the phase difference.
Claims31
A method for determining delays of multipath signals comprising:
- receiving a power delay profile comprising at least a first and second multipath signal;
- detecting a first peak power value in the power delay profile;
- subtracting power values associated with the first detected peak power value from the power delay profile to generate a modified power delay profile;
- detecting a second peak power value in the modified power delay profile;
- subtracting power values associated with the second detected peak power value from the modified power delay profile to generate another modified power delay profile;
- and
- determining the delays associated with the first and second multipath signals by locating a peak power associated with the first and second multipath signals in the another modified power delay profile.
4 more elements
A method for determining delays of multipath signals comprising:
- receiving a power delay profile comprising at least a first and second multipath signal;
- determining a first set of delays associated with the first and second multipath signals, the first set of delays being determined without accounting for a phase difference between the first and second multipath signals;
- performing a channel estimation using the determined first set of delays, the channel estimation producing a phase difference between the first and second multipath signals;
- determining a second set of delays associated with the first and second multipath signals, the second set of delays being determined based on the phase difference produced by the channel estimation.
1 more element
A method for estimating delays of multipath signals comprising:
- receiving a power delay profile comprising at least a first and second multipath signal;
- subtracting a power value associated with a peak of the first multipath signal from the received power delay profile to generate a first modified power delay profile;
- subtracting a power value associated with a peak of the second multipath signal from the first modified power delay profile to generate a second modified power delay profile;
- calculating a difference between the power value associated with a peak of the first multipath signal in the second modified power delay profile and the power value associated with the peak of the first multipath signal in the first modified power delay profile;
- adjusting a power value associated with a peak of the first multipath signal in the second modified power delay profile as a function of the difference to generate another modified power delay profile;
- and
- determining a delay associated with the first multipath signal using the another modified power delay profile.
4 more elements
A RAKE receiver comprising:
- a path searcher which receives a power delay profile comprising at least a first and second multipath signal, detects a first peak power value in the power delay profile, subtracts power values associated with the first detected peak power value from the power delay profile to generate a modified power delay profile, detects a second peak power value in the modified power delay profile, subtracts power values associated with the second detected peak power value from the modified power delay profile to generate another modified power delay profile, and determines the delays associated with the first and second multipath signals by locating a peak power associated with the first and second multipath signals in the another modified power delay profile.
A RAKE receiver comprising:
- a path searcher which receives a power delay profile comprising at least a first and second multipath signal, determines a first set of delays associated with the first and second multipath signals, the first set of delays being determined without accounting for a phase difference between the first and second multipath signals, performs a channel estimation using the determined first set of delays, the channel estimation producing a phase difference between the first and second multipath signals, and determines a second set of delays associated with the first and second multipath signals, the second set of delays being determined based on the phase difference produced by the channel estimation.
A RAKE receiver comprising:
- a path searcher which receives a power delay profile comprising at least a first and second multipath signal, subtracts a power value associated with a peak of the first multipath signal from the received power delay profile to generate a first modified power delay profile, subtracts a power value associated with a peak of the second multipath signal from the first modified power delay profile to generate a second modified power delay profile, calculates a difference between the power value associated with a peak of the first multipath signal in the second modified power delay profile and the power value associated with the peak of the first multipath signal in the first modified power delay profile, adjusts a power value associated with a peak of the first multipath signal in the second modified power delay profile as a function of the difference to generate another modified power delay profile;
- and
- a channel estimator which performs channel estimation using the another modified power delay profile.
A method for determining delays of multipath signals comprising:
- a) receiving a power delay profile comprising a plurality of multipath signals;
- b) detecting a peak power value in the power delay profile;
- c) subtracting power values associated with the detected peak power value from a most recent power delay profile to generate a new power delay profile;
- d) repeating steps b)–c) until a predetermined number of peaks have been detected, where the generated new power delay profile from one iteration is the most recent power delay profile of the next iteration;
- and
- e) determining delays associated with the plurality of multipath signals by locating peak powers associated with the plurality of multipath signals of the most recent power delay profile.
3 more elements
A method for determining delays of multipath signals comprising:
- a) receiving a power delay profile comprising a plurality of multipath signals;
- b) detecting a peak power value in the power delay profile;
- c) subtracting power values associated with the detected peak power value from a most recent power delay profile to generate a new power delay profile;
- d) repeating steps b)–c) until a predetermined number of peaks have been detected, where the generated new power delay profile from one iteration is the most recent power delay profile of the next iteration;
- e) determining a first set of delays associated with the plurality of multipath signals by locating peak powers associated with the plurality of multipath signals the most recent power delay profile;
- f) performing a channel estimation using the determined first set of delays, the channel estimation producing phase differences between the plurality of multipath signals;
- g) repeating steps b)–d), wherein the subtacting step employs the phase differences produced by the channel estimation;
- and
- h) determining a second set of delays associated with the plurality of multipath signals by locating the peak powers associated with the plurality of multipath signals in the most recent power delay profile.
6 more elements
Dependencies are inferred from the claim text.