Abstract
This paper examines the problem of carrier phase recovery in turbo-coded systems. We introduce a new concept of "a priori probability aided phase estimation", where the extrinsic information (log-likelihood ratio) obtained from turbo decoder is used to aid an iterative phase estimation process, which is based on a maximum-likelihood strategy. The phase estimator operates jointly with the turbo decoding rather than separately prior to the decoder as in traditional approaches. This technique provides reliable phase estimation with variance of estimation errors approaching the Cramer-Rao bound at very low signal-to-noise ratio and allows robust decoding with a wide range of phase errors. This paper addresses its application in turbo-coded binary phase-shift keying and quaternary phase-shift keying systems over the additive white Gaussian noise channel. The bit-error-rate performance is investigated and shows that the performance of this technique is very close to the optimally synchronised system and significantly outperforms the traditional non-data-aided method without using additional pilot symbols.
| Original language | English |
|---|---|
| Pages (from-to) | 2267-2276 |
| Number of pages | 10 |
| Journal | IEEE Transactions on Wireless Communications |
| Volume | 3 |
| Issue number | 6 |
| DOIs | |
| Publication status | Published - Nov 2004 |
Bibliographical note
Copyright © 2004 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.Keywords
- A priori information
- Cramer-Rao bound (CRB)
- extrinsic information
- iterative decoding
- log-likelihood function (LLF)
- MAP
- maximum-likelibood (ML) estimation
- turbo codes