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On the Computation of EXIT Characteristics for Symbol-Based Iterative Decoding

On the Computation of EXIT Characteristics for Symbol-Based Iterative Decoding
On the Computation of EXIT Characteristics for Symbol-Based Iterative Decoding
In this paper we propose an efficient method for computing index-based extrinsic information transfer (EXIT) charts, which are useful for estimating the convergence properties of non-binary iterative decoding. A standard method is to apply <i>a priori</i> reliability information to the <i>a posteriori</i> probability (APP) constituent decoder and compute the resulting average extrinsic information at the decoder output via multidimensional histogram measurements. However, this technique is only reasonable for very small index lengths as the complexity of this approach grows exponentially with the index length. We show that by averaging over a function of the extrinsic APPs for a long block the extrinsic information can be estimated with very low complexity. In contrast to using histogram measurements this method allows to generate EXIT charts even for larger index alphabets. Examples for a non-binary serial concatenated code and for turbo trellis-coded modulation, resp., demonstrate the capabilities of the proposed approach.
Kliewer, J
db8e88b6-36ba-4b88-90f3-5fae601c20ab
Ng, S. X.
e19a63b0-0f12-4591-ab5f-554820d5f78c
Hanzo, L.
66e7266f-3066-4fc0-8391-e000acce71a1
Kliewer, J
db8e88b6-36ba-4b88-90f3-5fae601c20ab
Ng, S. X.
e19a63b0-0f12-4591-ab5f-554820d5f78c
Hanzo, L.
66e7266f-3066-4fc0-8391-e000acce71a1

Kliewer, J, Ng, S. X. and Hanzo, L. (2006) On the Computation of EXIT Characteristics for Symbol-Based Iterative Decoding At International Symposium on Turbo Coding, Germany. 03 - 07 Apr 2006.

Record type: Conference or Workshop Item (Paper)

Abstract

In this paper we propose an efficient method for computing index-based extrinsic information transfer (EXIT) charts, which are useful for estimating the convergence properties of non-binary iterative decoding. A standard method is to apply <i>a priori</i> reliability information to the <i>a posteriori</i> probability (APP) constituent decoder and compute the resulting average extrinsic information at the decoder output via multidimensional histogram measurements. However, this technique is only reasonable for very small index lengths as the complexity of this approach grows exponentially with the index length. We show that by averaging over a function of the extrinsic APPs for a long block the extrinsic information can be estimated with very low complexity. In contrast to using histogram measurements this method allows to generate EXIT charts even for larger index alphabets. Examples for a non-binary serial concatenated code and for turbo trellis-coded modulation, resp., demonstrate the capabilities of the proposed approach.

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Published date: 2006
Additional Information: Event Dates: 3-7 April 2006
Venue - Dates: International Symposium on Turbo Coding, Germany, 2006-04-03 - 2006-04-07
Organisations: Southampton Wireless Group

Identifiers

Local EPrints ID: 262383
URI: http://eprints.soton.ac.uk/id/eprint/262383
PURE UUID: 34e2b12e-19d8-408e-95d0-4dc013567a7e
ORCID for S. X. Ng: ORCID iD orcid.org/0000-0002-0930-7194
ORCID for L. Hanzo: ORCID iD orcid.org/0000-0002-2636-5214

Catalogue record

Date deposited: 22 Apr 2006
Last modified: 18 Jul 2017 08:51

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Contributors

Author: J Kliewer
Author: S. X. Ng ORCID iD
Author: L. Hanzo ORCID iD

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