Polar codes, recently invented by Arikan, are the first class of codes known to achieve
the symmetric capacity for a large class of channels. The symmetric capacity is the highest
achievable rate subject to using the binary input letters of the channel with equal probability.
Polar code construction is based on a phenomenon called channel polarization.
The encoding as well as the decoding operation of polar codes can be implemented with
O(N logN) complexity, where N is the blocklength of the code.
In this work, we study the factor graph representation of finite-length polar codes and
their effect on the belief propagation (BP) decoding process over Binary Erasure Channel
(BEC). Particularly, we study the parity-check-based (H-Based) as well as the generator
based (G-based) factor graphs of polar codes. As these factor graphs are not unique for
a code, we study and compare the performance of Belief Propagation (BP) decoders on
number of well-known graphs. Error rates and complexities are reported for a number of
cases. Comparisons are also made with the Successive Cancellation (SC) decoder.
High errors are related to the so-called stopping sets of the underlying graphs. we
discuss the pros and cons of BP decoder over SC decoder for various code lengths. / Thesis (Master, Electrical & Computer Engineering) -- Queen's University, 2012-01-31 17:10:59.955
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:OKQ.1974/6996 |
| Date | 01 February 2012 |
| Creators | RAJAIE, TARANNOM |
| Contributors | Queen's University (Kingston, Ont.). Theses (Queen's University (Kingston, Ont.)) |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English, English |
| Detected Language | English |
| Type | Thesis |
| Rights | This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner. |
| Relation | Canadian theses |
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