Ho-Kyoung Lee

Serial concatenated turbo TCM coding scheme for enhanced VSB system

A new coding scheme using serial concatenated turbo TCM (SCTTCM) for enhanced VSB reception system is proposed. The proposed coding scheme is backward compatible with the conventional VSB receivers and at the same time is able to receive the enhanced stream. The conventional schemes are based on the idea of directly combining an outer convolutional code with the standard 8-VSB trellis code, but our proposed method inserts a random interleaver between the two codes comprising the SCTTCM. The performance of the proposed scheme is evaluated and compared with the conventional method considering both the mixed and non-mixed mode stream. We also apply the extrinsic information transfer chart (EXIT chart) method for the performance analysis of the proposed scheme.

Performance analysis of MTCM/CPFSK in correlated Rayleigh fading channels with perfect channel information

The upper bound on the pairwise error probability of MTCM/CPFSK with coherent detection is derived using a linear transformation for orthogonalizing the autocorrelation matrix of Rayleigh fading process with perfect CSI in the presence of an additive white Gaussian noise and a correlated Rayleigh fading. The analyzed performance well estimates the simulated performance for Doppler frequencies when BER is lower than 10/sup -3/.

Pairwise error probability evaluation of multiple symbol trellis-coded continuous phase frequency shift keying in a slow fading channel

This article evaluates the pairwise error probability (PEP) of multiple symbol trellis-coded modulation applied to continuous phase frequency shift keying (MTCM/CPFSK) in a slow fading environment with and without channel state information (CSI). The fading amplitude is assumed to be constant during an error event and distributed as Rician. For the case with CSI, the PEP is approximated using the Gauss-Chebysev formula and a tight upper bound is presented. For the case without CSI, a simplified upper bound is derived by using the improved Chernoff bound technique. Simulation results are also presented.

STBC Detection Algorithm Using Double-Decision-Feedback Scheme in Time-Varying Rayleigh-Fading Channel

In this paper, we study STBC(Space Time Block Code) detection scheme in time varying Rayleigh fading channel. When the channel is varying during the time duration of STBC, the channel matrix of orthogonal STBC is not orthogonal. To get the optimum reception performance in this channel, joint ML detection scheme may be used, however this scheme requires high computation complexity. Decision feedback scheme is proposed to reduce the computation complexity with less reception performance. In this paper, we propose a novel STBC detection algorithm using double decision feedback which is less complex than the joint ML scheme and outperforms the conventional decision feedback scheme.

Serial Concatenated Turbo TCM Coding Scheme for Enhanced VSB

Recently, research on the enhancement of the conventional VSB scheme for DTV signal transmission have been done. Not to affect on the performance of the widely spread conventional receivers and at the same time be able to receive the enhanced stream. there have been efforts to enhance the coding scheme which is backward compatible with the conventional method. The conventional schemes proposed so far is based on the idea of combining a new trellis encoder with the standard 8-VSB trellis encoder. In this paper, we Propose serial concatenated turbo TCM scheme which combines two trellis encoder with the interleaver between them. We compare the performance of the proposed scheme and the existing scheme through computer simulation.

System performance analysis with error-controlled data in a voice/data DS-CDMA system

In this paper, we analyze the effect of adopting an ARQ protocol in a voice/data DS-CDMA system. Basically, we consider the IS-95 type reverse link DS-CDMA system which supports two kinds of services, traditional voice and data services. This system includes a 1/3 rate convolutional code for FEC and shortened binary CRC codes for ARQ. First, we find the optimum ARQ code rate which maximizes the number of concurrent users. Average packet transmission time and the normalized system throughput are analyzed for various ARQ protocols. The analysis results show that the number of concurrent users is maximized when the ARQ code rate is about 0.935 and the total system throughput is optimized when the ARQ code rate is about 0.97.