Channel decoding for multicarrier signal transmission by means of DC-offset and carrier-frequency offset-dependent weighting of reliability information

• US 20040228418A1
• Filed: 05/11/2004
• Published: 11/18/2004
• Est. Priority Date: 05/14/2003
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Infineon Technologies AG
• Inventors: Brotje, Lars, Kammeyer, Karl-Dirk, Vogeler, Sven, Kuhn, Volker
• Granted Patent: US 7,664,186 B2
• Time in Patent Office: Days
• US Class Current: 375/260
• CPC Class Codes: H04L 1/0045 Arrangements at the receiver end
• CPC Class Codes: H04L 25/067 providing soft decisions, i.e. decisions together with an estimate of reliability H04L25/068 and H04L25/069 take precedence; sequence estimation techniques H04L25/03178
• CPC Class Codes: H04L 27/2657 Carrier synchronisation
• CPC Class Codes: H04L 27/2691 involving interference determination or cancellation

Abstract

The influence of a DC offset with a carrier-frequency offset at the same time is reduced in that the values of the assumed or determined DC offset and of the assumed or determined carrier-frequency offset are included in the determination of reliability information for one sub-carrier in the multicarrier system, and the reliability information is corrected in this way. A factor M, where M<1, is defined for each sub-carrier on the basis of the values for the DC offset and for the carrier-frequency offset, and the reliability information for the sub-carriers is multiplied by these factors M.

Claims

1. A method for reduction of interference caused by a DC offset with a concurrent carrier-frequency offset in received channel-coded data symbols in a multicarrier system with two or more sub-carriers, comprising:

determining reliability information for channel decoding for at least one sub-carrier, wherein the reliability information is corrected based on a magnitude of the interference; and

weighting input values to a channel decoder with the reliability information.

2. The method of claim 1, wherein the magnitude of the interference is determined based on assumed or determined values for the DC offset and the carrier-frequency offset, respectively.

3. The method of claim 1, wherein the correction is carried out by multiplication of the reliability information by a factor M, wherein M is a function of at least one of the DC offset and carrier-frequency offset.

4. The method of claim 1, wherein the reliability information is corrected only for sub-carriers that are within a predetermined interval from a frequency of the carrier-frequency offset.

5. The method of claim 1, wherein a value of the reliability information is reduced on a basis of the magnitude of the interference.

6. The method of claim 3, wherein the correction is carried out by multiplication of the reliability information by a factor M<

1.

7. The method of claim 6, wherein the factor M is chosen to be a smaller value the closer the sub-carrier is to a frequency of the carrier-frequency offset.

8. A method for reception and for processing of a channel-coded data signal in a multicarrier system having two or more sub-carriers, in which a method according to claim 1 is used in order to reduce interference which is caused by a DC offset with a carrier-frequency offset at the same time.

9. The method of claim 8, wherein the reception method comprises a direct-mixing receiving method.