Turbo Decoding With Early State Decisions
Turbo codes was first presented in 1993 by C. Berrou, A. Glavieux and P. Thitimajshima. Since then this class of error correcting codes has become one of the most popular, because of its good properties. The turbo codes are able to come very close to theoretical limit, the Shannon limit. Turbo codes...
Main Author: | |
---|---|
Format: | Others |
Language: | English |
Published: |
Linköpings universitet, Institutionen för systemteknik
2008
|
Subjects: | |
Online Access: | http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-11694 |
id |
ndltd-UPSALLA1-oai-DiVA.org-liu-11694 |
---|---|
record_format |
oai_dc |
spelling |
ndltd-UPSALLA1-oai-DiVA.org-liu-116942013-01-08T13:47:39ZTurbo Decoding With Early State DecisionsengLindblom, JohannesLinköpings universitet, Institutionen för systemteknikInstitutionen för systemteknik2008turbo codesturbo decodingerror correcting codesconvolutional codesMAP-decoderlog-MAP-decoderearly decisionsearly state decisionsElectronicsElektronikTurbo codes was first presented in 1993 by C. Berrou, A. Glavieux and P. Thitimajshima. Since then this class of error correcting codes has become one of the most popular, because of its good properties. The turbo codes are able to come very close to theoretical limit, the Shannon limit. Turbo codes are for example used in the third generation of mobile phone (3G) and in the standard IEEE 802.16 (WiMAX). There are some drawbacks with the algorithm for decoding turbo codes. The deocoder uses a Maximum A Posteriori (MAP) algorithm, which is a complex algorith. Because of the use of many variables in the decoder the decoding circuit will consume a lot of power due to memory accesses and internal communication. One way in which this can be reduced is to make early decisions. In this work I have focused on making early decision of the encoder states. One major part of the work was also to be sure that the expressions were written in a way that as few variables as possible are needed. A termination condition is also introduced. Simulations based on estimations of the number of memory accesses, shows that the number of memory accesses will significantly decrease. Student thesisinfo:eu-repo/semantics/bachelorThesistexthttp://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-11694application/pdfinfo:eu-repo/semantics/openAccess |
collection |
NDLTD |
language |
English |
format |
Others
|
sources |
NDLTD |
topic |
turbo codes turbo decoding error correcting codes convolutional codes MAP-decoder log-MAP-decoder early decisions early state decisions Electronics Elektronik |
spellingShingle |
turbo codes turbo decoding error correcting codes convolutional codes MAP-decoder log-MAP-decoder early decisions early state decisions Electronics Elektronik Lindblom, Johannes Turbo Decoding With Early State Decisions |
description |
Turbo codes was first presented in 1993 by C. Berrou, A. Glavieux and P. Thitimajshima. Since then this class of error correcting codes has become one of the most popular, because of its good properties. The turbo codes are able to come very close to theoretical limit, the Shannon limit. Turbo codes are for example used in the third generation of mobile phone (3G) and in the standard IEEE 802.16 (WiMAX). There are some drawbacks with the algorithm for decoding turbo codes. The deocoder uses a Maximum A Posteriori (MAP) algorithm, which is a complex algorith. Because of the use of many variables in the decoder the decoding circuit will consume a lot of power due to memory accesses and internal communication. One way in which this can be reduced is to make early decisions. In this work I have focused on making early decision of the encoder states. One major part of the work was also to be sure that the expressions were written in a way that as few variables as possible are needed. A termination condition is also introduced. Simulations based on estimations of the number of memory accesses, shows that the number of memory accesses will significantly decrease. |
author |
Lindblom, Johannes |
author_facet |
Lindblom, Johannes |
author_sort |
Lindblom, Johannes |
title |
Turbo Decoding With Early State Decisions |
title_short |
Turbo Decoding With Early State Decisions |
title_full |
Turbo Decoding With Early State Decisions |
title_fullStr |
Turbo Decoding With Early State Decisions |
title_full_unstemmed |
Turbo Decoding With Early State Decisions |
title_sort |
turbo decoding with early state decisions |
publisher |
Linköpings universitet, Institutionen för systemteknik |
publishDate |
2008 |
url |
http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-11694 |
work_keys_str_mv |
AT lindblomjohannes turbodecodingwithearlystatedecisions |
_version_ |
1716529214852694016 |