180 Rotationally Invariant Repeat-Accumulate Codes

Wangrok OH  Kyungwhoon CHEUN  

IEICE TRANSACTIONS on Communications   Vol.E92-B   No.5   pp.1884-1887
Publication Date: 2009/05/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.E92.B.1884
Print ISSN: 0916-8516
Type of Manuscript: LETTER
Category: Fundamental Theories for Communications
repeat-accumulate codes,  phase synchronization,  phase ambiguity,  

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In digital communication systems employing binary phase-shift keying and non-data-aided carrier phase recovery, a 180 carrier phase ambiguity is inevitable. Here, we propose a simple modification to the standard regular repeat-accumulate (RA) code structure by exploiting the differential encoding inherent to the inner encoder of RA codes resulting in codes that are 180 rotationally invariant. The proposed code structure exhibit performance virtually identical to that of standard regular RA codes with zero carrier phase offset under both zero and 180 carrier phase offsets with negligible additional hardware complexity.