Decision-Directed Carrier Phase and Symbol Timing Recovery for LDPC-Coded Systems

In this paper, we consider the effect of different rules of symbol decision on the performance of decision-directed synchronizers for LDPC-coded systems. Different from the conventional hard symbol decision based on the Maximum-A- Posteriori (MAP) criterion, soft symbol decision can be considered as the Minimum-Mean-Square-Error (MMSE) estimation of the transmitted symbol. By whether or not the coding constraints are taken into account, soft symbol decision is derived in non-code-aided (NCA) mode and code-aided (CA) mode, respectively. The performance of the soft decision-directed (SDD) synchronizer is compared with that of the hard decision-directed (HDD) counterpart in both NCA and CA mode. Simulation results show that, without much implementation complexity increase, the jitter performance of the synchronizer in CA mode significantly outperforms that in NCA mode. It is also observed that, in the scenario of this paper, SDD synchronizer works only slightly better than HDD synchronizer.

[1]  Bartosz Mielczarek,et al.  Timing error recovery in turbo-coded systems on AWGN channels , 2002, IEEE Trans. Commun..

[2]  Heidi Steendam,et al.  The Cramer-Rao bound for phase estimation from coded linearly modulated signals , 2003, IEEE Communications Letters.

[3]  Heidi Steendam,et al.  Performance Analysis of ML-Based Feedback Carrier Phase Synchronizers for Coded Signals , 2007, IEEE Transactions on Signal Processing.

[4]  Heinrich Meyr,et al.  Digital communication receivers - synchronization, channel estimation, and signal processing , 1997, Wiley series in telecommunications and signal processing.

[5]  Luc Vandendorpe,et al.  A Theoretical Framework for Soft-Information-Based Synchronization in Iterative (Turbo) Receivers , 2005, EURASIP J. Wirel. Commun. Netw..

[6]  Riccardo De Gaudenzi,et al.  Performance analysis of decision-directed maximum-likelihood phase estimators for M-PSK modulated signals , 1995, IEEE Trans. Commun..

[7]  K. Mueller,et al.  Timing Recovery in Digital Synchronous Data Receivers , 1976, IEEE Trans. Commun..

[8]  Luc Vandendorpe,et al.  Code-Aided Turbo Synchronization , 2007, Proceedings of the IEEE.

[9]  Heidi Steendam,et al.  Iterative carrier phase synchronization for low-density parity-check coded systems , 2003, IEEE International Conference on Communications, 2003. ICC '03..

[10]  Umberto Mengali,et al.  Synchronization Techniques for Digital Receivers , 1997, Applications of Communications Theory.

[11]  Haige Xiang,et al.  Iterative carrier phase recovery methods in turbo receivers , 2005, IEEE Commun. Lett..

[12]  William G. Cowley,et al.  The performance of two symbol timing recovery algorithms for PSK demodulators , 1994, IEEE Trans. Commun..

[13]  Marco Luise,et al.  Embedding carrier phase recovery into iterative decoding of turbo-coded linear modulations , 2004, IEEE Transactions on Communications.

[14]  S. McLaughlin,et al.  Joint timing recovery and turbo equalization for coded partial response channels , 2002 .

[15]  Luc Vandendorpe,et al.  On Maximum-Likelihood Timing Synchronization , 2007, IEEE Transactions on Communications.