Error correction decoder for turbo code

• US 7,032,163 B2
• Filed: 08/17/2001
• Issued: 04/18/2006
• Est. Priority Date: 07/06/2001
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Yano, Takashi, Tamaki, Tsuyoshi
• Primary Examiner(s): Lamarre, Guy J.
• Application Number:
  US09/931,252
• Publication Number:
  US 20030014712A1
• Time in Patent Office: 1,705 Days
• Field of Search: 714786-796, 714/755, 714/780
• US Class Current: 714/786
• CPC Class Codes: H03M 13/2975 Judging correct decoding, e.g. iteration stopping criteria
• CPC Class Codes: H03M 13/4146 soft-output Viterbi decoding according to Battail and Hagenauer in which the soft-output is determined using path metric differences along the maximum-likelihood path, i.e. "SOVA" decoding
• CPC Class Codes: H03M 13/4169 using traceback H03M13/4192 takes precedence
• CPC Class Codes: H03M 13/6337 Error control coding in combination with channel estimation
• CPC Class Codes: H03M 13/658 Scaling by multiplication or division

Abstract

To provide a turbo decoder reducing power consumption by reducing an operational processing amount while ensuring sufficient error correction capability, there is provided a constitution including an input signal memory for storing turbo-coded received data, a decoder for executing SOVA decoding, a decoded result memory for storing a decoded result, a control block for executing repeated decoding, a memory stored with an interleave pattern, and judging means for judging reliability of a decoded result and the reliability of the decoded result is judged based on a soft decision value outputted from the SOVA decoder and when desired reliability is satisfied by the judgment result, the repeated decoding is finished.

Claims

1. A turbo decoder comprising:

a decoder for inputting data turbo-coded for correcting an error and repeatedly carrying out soft output decoding to thereby restore original data;

judging means for judging a reliability of a soft output decoding result from said decoder provided by the soft output decoding from statistics of the soft output decoding result; and

controlling means for controlling the number of iterations of the soft output decoding based on a result of judgment, by said judging means, of the reliability of the soft output decoding result from said decoder,

wherein said judging means uses a mean value and a dispersion value of the soft output decoding result from said decoder as the statistics for judging the reliability of the soft output decoding result from said decoder.

2. A turbo decoder comprising:

a decoder for inputting data turbo-coded for correcting an error and repeatedly carrying out soft output decoding to thereby restore original data;

judging means for judging a reliability of a soft output decoding result from said decoder provided by the soft output decoding from statistics of the soft output decoding result; and

controlling means for controlling the number of iterations of the soft output decoding based on a result of judgment, by said judging means, of the reliability of the soft output decoding result from said decoder,

wherein said judging means uses a mean value and a minimum value of the soft output decoding result from said decoder as the statistics for judging the reliability of the soft output decoding result from said decoder.

3. A turbo decoder comprising:

a decoder for inputting data turbo-coded for correcting an error and repeatedly carrying out soft output decoding to thereby restore original data;

judging means for judging a reliability of a soft output decoding result from said decoder provided by the soft output decoding from statistics of the soft output decoding result; and

controlling means for controlling the number of iterations of the soft output decoding based on a result of judgment, by said judging means of the reliability of the soft output decoding result from said decoder,

wherein said judging means uses a maximum value and a minimum value of the soft output decoding result from said decoder as the statistics for judging the reliability of the soft output decoding result from said decoder.

4. A mobile station of a mobile communication system, said mobile station comprising:

a radio frequency circuit for receiving a radio frequency signal of data turbo-coded for correcting an error by an antenna and outputting a received signal;

a receiver for outputting original data from the received signal as received data; and

a signal processor for subjecting the received data to a signal processing;

the receiver further comprising;

a turbo decoder for decoding the turbo-coded data constituting the received signal for outputting the received data,

the turbo decoder comprising;

a decoder for inputting the turbo-coded data and repeatedly carrying out soft output decoding to thereby restore the original data;

judging means for judging a reliability of a soft output decoding result from said decoder provided by the soft output decoding from statistics of the soft output decoding result, and

controlling means for controlling the number of iterations of the soft output decoding based on a result of judgment, by said judging means, of the reliability of the soft output decoding result from said decoder,

wherein said judging means uses, as the statistic for judging the reliability, one of;

a mean value and a dispersion value of the soft output decoding result from said decoder,

a mean value and a minimum value of the soft output decoding result from said decoder, and

a maximum value and a minimum value of the soft output decoding result from said decoder.

5. A base station of a mobile communication system, said base station comprising:

a radio frequency circuit for receiving a radio frequency signal of data turbo-coded for correcting an error by an antenna and outputting a received signal;

a receiver for outputting original data from the received signal as received data; and

a station interface circuit for transmitting the received data to a communication network,

the receiver comprising;

a turbo decoder for decoding the turbo-coded data and outputting the received data,

the turbo decoder comprising;

a decoder for inputting the turbo-coded data constituting the received signal and repeatedly carrying out soft output decoding to thereby restore the original data,

judging means for judging a reliability of a soft output decoding result from said decoder provided by the soft output decoding from statistics of the soft output decoding result, and

controlling means for controlling the number of iterations of the soft output decoding based on a result of judgment, by said judging means, of the reliability of the soft output decoding result from said decoder,

wherein said judging means uses, as the statistic for judging the reliability, one of;

a mean value and a dispersion value of the soft output decoding result from said decoder,

a mean value and a minimum value of the soft output decoding result from said decoder, and

a maximum value and a minimum value of the soft output decoding result from said decoder.