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US 7,120,207 B2Granted
Transmission method and radio receiver
AssigneeNokia Corporation
InventorRisto Nordman
Life of this patent
Estimating the term…
Abstract
The invention relates to a method and a receiver for obtaining a soft decision in detection of a TFM signal. In the method, the phase of a signal sample is reversed rotated twice in the way that the real part of the sample indicates the phase of the sample and that the rotation is opposite to the phase belonging to the old state of a trellis diagram. Transition metrics are completed with the aid of the real part of the signal sample. Then path metrics are computed, the path with larger metrics is selected as a survivor and the survivor with the largest metric is selected as the best survivor. The sign of the demodulated bit is determined and the weight of the demodulated bit is calculated.
Claims32
A method for obtaining a soft decision in detection of a TFM signal, comprising:
- sampling a received signal,
- reverse rotating the phase of a signal sample in the way that the real part of a complex signal indicates the phase of the sample to produce phase changes of possible transitions,
- reverse rotating the phase changes of possible transitions determined by the modulation method used so that the rotation is opposite to the phase belonging to the old state of a trellis diagram,
- computing transition metrics for the state transitions in a trellis diagram with the aid of the real part of the signal sample and computing path metrics for each survivor path,
- selecting the path with larger metrics as a survivor from paths entering a state node, and the phase of that survivor is set as the phase state of the new correlative state in question,
- selecting the survivor with the largest metric as the best survivor,
- determining the sign of the demodulated bit with the aid of the last bit of the previous state of the best survivor and calculating the weight of the demodulated bit as the difference of the path metrics of the best survivor and a selected path joining it.
4 more elements
A method for obtaining a soft decision in detection of a TFM signal, comprising:
- sampling a received signal,
- reverse rotating the phase of a signal sample in the way that the real part of a complex signal indicates the phase of the sample to produce phase changes of possible transitions,
- reverse rotating the phase changes of possible transitions determined by the modulation method used so that the rotation is opposite to the phase belonging to the old state of a trellis diagram,
- rotating a carrier phase,
- computing transition metrics for the state transitions in a trellis diagram with the aid of the real part of the signal sample and computing path metrics for each survivor path,
- selecting the path with larger metrics as a survivor from paths entering to a state node, and the phase of that survivor is set as the phase state of the new correlative state in question,
- selecting the survivor with the largest metric as the best survivor,
- determining the sign of the demodulated bit with the aid of the last bit of the previous state of the best survivor and calculating the weight of the demodulated bit as the difference of the path metrics of the best survivor and a selected path joining it.
5 more elements
A method for obtaining a soft decision in detection of a TFM signal, comprising:
- sampling a received signal,
- reverse rotating the phase of a signal sample in the way that the real part of a complex signal indicates the phase of the sample to produce phase changes of possible transitions,
- reverse rotating the phase changes of possible transitions determined by the modulation method used so that the rotation is opposite to the phase belonging to the old state of a trellis diagram,
- computing transition metrics for the state transitions in a trellis diagram with the aid of the real part of the signal sample using two earlier symbols as an original state of the trellis and computing path metrics for each survivor path,
- selecting the path with larger metrics as a survivor from paths entering a state node, and the phase of that survivor is set as the phase state of the new correlative state in question,
- selecting the survivor with the largest metric as the best survivor,
- determining the sign of the demodulated bit with the aid of the last bit of the previous state of the best survivor and calculating the weight of the demodulated bit as the difference of the path metrics of the best survivor and a selected path joining it.
4 more elements
A method for obtaining a soft decision in detection of a TFM signal, comprising:
- sampling a received signal,
- reverse rotating the phase of a signal sample in the way that the real part of a complex signal indicates the phase of the sample to produce phase changes of possible transitions,
- reverse rotating the phase changes of possible transitions determined by the modulation method used so that the rotation is opposite to the phase belonging to the old state of a trellis diagram,
- rotating a carrier phase,
- computing transition metrics for the state transitions in a trellis diagram with the aid of the real part of the signal sample using two earlier symbols as the original state of the trellis and computing path metrics for each survivor path,
- selecting the path with larger metrics as a survivor from pathsentering a state node, and the phase of that survivor is set as the phase state of the new correlative state in question,
- selecting the survivor with the largest metric as the best survivor,
- determining the sign of the demodulated bit with the aid of the last bit of the previous state of the best survivor and calculating the weight of the demodulated bit as the difference of the path metrics of the best survivor and a selected path joining it.
5 more elements
A receiver for obtaining a soft decision in detection of a TFM signal comprising:
- means for sampling a received signal,
- means for reverse rotating the phase of a signal sample in the way that the real part of a complex signal indicates the phase of the sample to produce phase changes of possible transitions,
- means for reverse rotating the phase changes of possible transitions determined by the modulation method used so that the rotation is opposite to the phase belonging to the old state of a trellis diagram,
- means for computing transition metrics for the state transitions in a trellis diagram with the aid of the real part of the signal sample and computing path metrics for each survivor path,
- means for selecting the path with larger metrics as a survivor from paths entering a state node, and the phase of that survivor is set as the phase state of the new correlative state in question,
- means for selecting the survivor with the largest metric as the best survivor,
- means for determining the sign of the demodulated bit with the aid of the last bit of the previous state of the best survivor and calculating the weight of the demodulated bit as the difference of the path metrics of the best survivor and a selected path joining it.
4 more elements
A receiver for obtaining a soft decision in detection of a TFM signal comprising:
- means for sampling a received signal,
- means for reverse rotating the phase of a signal sample in the way that the real part of a complex signal indicates the phase of the sample to produce phase changes of possible transitions,
- means for reverse rotating the phase changes of possible transitions determined by the modulation method used so that the rotation is opposite to the phase belonging to the old state of a trellis diagram,
- means for rotating a carrier phase,
- means for computing transition metrics for the state transitions in a trellis diagram with the aid of the real part of the signal sample and computing path metrics for each survivor path,
- means for selecting the path with larger metrics as a survivor from paths entering a state node, and the phase of that survivor is set as the phase state of the new correlative state in question,
- means for selecting the survivor with the largest metric as the best survivor,
- means for determining the sign of the demodulated bit with the aid of the last bit of the previous state of the best survivor and calculating the weight of the demodulated bit as the difference of the path metrics of the best survivor and a selected path joining it.
5 more elements
A receiver for obtaining a soft decision in detection of a TFM signal comprising:
- means for sampling a received signal,
- means for reverse rotating the phase of a signal sample in the way that the real part of a complex signal indicates the phase of the sample to produce phase changes of possible transitions,
- means for reverse rotating the phase changes of possible transitions determined by the modulation method used so that the rotation is opposite to the phase belonging to the old state of a trellis diagram,
- means for computing transition metrics for the state transitions in a trellis diagram with the aid of the real part of the signal sample using two earlier symbols as an original state of the trellis and computing path metrics for each survivor path,
- means for selecting the path with larger metrics as a survivor from paths entering a state node, and the phase of that survivor is set as the phase state of the new correlative state in question,
- means for selecting the survivor with the largest metric as the best survivor,
- means for determining the sign of the demodulated bit with the aid of the last bit of the previous state of the best survivor and calculating the weight of the demodulated bit as the difference of the path metrics of the best survivor and a selected path joining it.
4 more elements
A receiver for obtaining a soft decision in detection of a TFM signal comprising:
- means for sampling a received signal,
- means for reverse rotating the phase of a signal sample in the way that the real part of a complex signal indicates the phase of the sample,
- means for reverse rotating the phase changes of possible transitions determined by the modulation method used so that the rotation is opposite to the phase belonging to the old state of a trellis diagram,
- means for rotating a carrier phase,
- means for computing transition metrics for the state transitions in a trellis diagram with the aid of the real part of the signal sample using two earlier symbols as the original state of the trellis and computing path metrics for each survivor path,
- means for selecting the path with larger metrics as a survivor from paths entering a state node, and the phase of that survivor is set as the phase state of the new correlative state in question,
- means for selecting the survivor with the largest metric as the best survivor,
- means for determining the sign of the demodulated bit with the aid of the last bit of the previous state of the best survivor and calculating the weight of the demodulated bit as the difference of the path metrics of the best survivor and a selected path joining it.
5 more elements
Dependencies are inferred from the claim text.