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

• US 7,664,186 B2
• Filed: 05/11/2004
• Issued: 02/16/2010
• Est. Priority Date: 05/14/2003
• Status: Expired due to Fees

• Current Assignee: Intel Corporation
• Original Assignee: Infineon Technologies AG
• Inventors: Kühn, Volker, Brötje, Lars, Kammeyer, Karl-Dirk, Vogeler, Sven
• Primary Examiner(s): Liu; Shuwang
• Assistant Examiner(s): PATEL, DHAVAL V
• Application Number:
  US10/842,970
• Publication Number:
  US 20040228418A1
• Time in Patent Office: 2,107 Days
• Field of Search: 375/326
• 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 processing received channel coded data symbols in an orthogonal frequency division multiplexing (OFDM) system with a plurality of sub-carriers, the received channel coded data symbols being affected by a disturbance caused by a DC offset with a concurrent carrier-frequency offset in the received channel-coded data symbols in a multicarrier system with two or more sub-carriers, comprising:

determining reliability information for channel decoding for two or more sub-carriers of the plurality of sub-carriers, wherein the reliability information represents a probability with which a channel decoded data symbol corresponds to a transmitted data symbol;

correcting the reliability information based on a magnitude of the disturbance; and

weighting input values to a channel decoder with the corrected reliability information,

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, and 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.

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

4. The method of claim 1, wherein the correction is carried out by multiplication of the reliability information by a factor M<

1.

5. 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 process received symbols affected by a disturbance which is caused by a DC offset with a carrier-frequency offset at the same time.

6. The method of claim 5, wherein the reception method comprises a direct-mixing receiving method.

7. The method of claim 1, wherein the reliability information differs for each sub-carrier.

8. A method for processing received channel coded data symbols in an orthogonal frequency division multiplexing (OFDM) system with a plurality of sub-carriers, the received channel coded data symbols being affected by a disturbance caused by a DC offset with a concurrent carrier-frequency offset in the received channel-coded data symbols in a multicarrier system with two or more sub-carriers, comprising:

determining reliability information for channel decoding for two or more sub-carriers of the plurality of sub-carriers, wherein the reliability information represents a probability with which a channel decoded data symbol corresponds to a transmitted data symbol;

correcting the reliability information based on a magnitude of the disturbance; and

weighting input values to a channel decoder with the corrected reliability information,

wherein the reliability information is corrected only for sub-carriers that are within a predetermined frequency interval from a frequency of the carrier-frequency offset.