Demodulator circuit
View Patent ↗The invention relates to a demodulator circuit in a communication system using a multi-carrier modulation scheme. The demodulator uses channel state information for respective carriers in the multi-carrier modulation to de-map the received data.
1. A method of determining decision data for an information signal on a sub-carrier of a multi-carrier modulated signal using an electronic signal processor, the method comprising:
electronically determining provisional decision data, based on a detected sub-carrier position relative to a constellation grid; and
electronically allowing the provisional decision data to remain the same if channel state information for the respective sub-carrier is less than a first threshold, comprising adjusting the provisional decision data by a predetermined amount if the channel state information for the respective sub-carrier is greater than the first threshold and less than a second threshold, wherein the provisional decision data is adjusted by a second predetermined amount if the channel state information for the respective sub-carrier is greater than the second threshold and less than a third threshold;
said first threshold value being set relative to a mean channel state information of a plurality of sub-carriers.
2. The method of claim 1 wherein electronically allowing the provisional decision data to remain the same if the channel state information for the respective sub-carrier is less than the first threshold comprises adjusting the provisional decision data by a second predetermined amount if the channel state information for the respective sub-carrier is greater than the second threshold and less than the third threshold that is greater than the mean channel state information of the plurality of sub-carriers.
3. The method of claim 1 wherein electronically allowing the provisional decision data to remain the same if the channel state information for the respective sub-carrier is less than the first threshold comprises adjusting the provisional decision data by a third predetermined amount if the channel state information for the respective sub-carrier is greater than a third threshold.
4. The method of claim 1 wherein the provisional decision data is adjusted by a third predetermined amount if the channel state information for the respective sub-carrier is greater than the third threshold that is greater than the mean channel state information of the plurality of sub-carriers.
5. The method of claim 1 wherein electronically allowing the provisional decision data to remain the same if the channel state information for the respective sub-carrier is less than the first threshold comprises:
allowing the provisional decision data to remain the same if the channel state information for the respective sub-carrier is less than the first threshold that is greater than the mean channel state information of the plurality of sub-carriers; and
adjusting the provisional decision data by a first predetermined amount if the channel state information for the respective sub-carrier is greater than the first threshold.
6. The method of claim 5 wherein the provisional decision data is adjusted by a second predetermined amount if the channel state information for the respective sub-carrier is greater than a second threshold that is greater than the mean channel state information of the plurality of sub-carriers and less than a third threshold that is greater than the mean channel state information of the plurality of sub-carriers.
7. The method of claim 6 wherein the provisional decision data is adjusted by a third predetermined amount if the channel state information for the respective sub-carrier is greater than the third threshold.
8. An electronic signal processor comprising:
a system for electronically determining provisional decision data, based on a detected sub-carrier position relative to a constellation grid;
a system for electronically allowing the provisional decision data to remain the same if channel state information for the respective sub-carrier is less than a first threshold;
said first threshold value being set relative to a mean channel state information of a plurality of sub-carriers; and
a system for adjusting the provisional decision data by a first predetermined amount if the channel state information for the respective sub-carrier is greater than the first threshold, wherein the provisional decision data is adjusted by a second predetermined amount if the channel state information for the respective sub-carrier is greater than a second threshold and less than a third threshold.
9. The system of claim 8 comprising a system for adjusting the provisional decision data by the second predetermined amount if the channel state information for the respective sub-carrier is greater than the second threshold and less than the third threshold that is greater than the mean channel state information of the plurality of sub-carriers.
10. The electronic signal processor of claim 8 wherein the provisional decision data is adjusted by a third predetermined amount if the channel state information for the respective sub-carrier is greater than the third threshold that is greater than the mean channel state information of a plurality of sub-carriers.
11. The electronic signal processor of claim 8 comprising:
a system for allowing the provisional decision data to remain the same if the channel state information for the respective sub-carrier is less than the first threshold that is greater than the mean channel state information of the plurality of sub-carriers; and
a system for adjusting the provisional decision data by the first predetermined amount if the channel state information for the respective sub-carrier is greater than the first threshold.
12. An electronic signal processor comprising:
a system for electronically determining provisional decision data, based on a detected sub-carrier position relative to a constellation grid;
a system for electronically allowing the provisional decision data to remain the same if channel state information for the respective sub-carrier is less than a first threshold, said first threshold value being set relative to a mean channel state information of a plurality of sub-carriers; and
a system for adjusting the provisional decision data by a first predetermined amount if the channel state information for the respective sub-carrier is greater than the first threshold, wherein the provisional decision data is adjusted by a second predetermined amount if the channel state information for the respective sub-carrier is greater than a second threshold and less than a third threshold, and wherein the provisional decision data is adjusted by a third predetermined amount if the channel state information for the respective sub-carrier is greater than the third threshold.
13. The electronic signal processor of claim 12 comprising a system for adjusting the provisional decision data by the second predetermined amount if the channel state information for the respective sub-carrier is greater than the second threshold that is greater than the mean channel state information of the plurality of sub-carriers and less than the third threshold.
14. The electronic signal processor of claim 12 comprising a system for adjusting the provisional decision data by the third predetermined amount if the channel state information for the respective sub-carrier is greater than the third threshold that is greater than the mean channel state information of the plurality of sub-carriers.
15. The electronic signal processor of claim 12 comprising:
a system for allowing the provisional decision data to remain the same if the channel state information for the respective sub-carrier is less than the first threshold that is greater than the mean channel state information of the plurality of sub-carriers; and
a system for adjusting the provisional decision data by the first predetermined amount if the channel state information for the respective sub-carrier is greater than the first threshold.