In-Ki Lee

Rate-compatible turbo product codes with non-symmetry block codes for satellite return link transmission technology

Soft-based linear block codes combined with linear modulation cannot obtain coding gains by increasing the number of iterations. In this paper, we propose rate-compatible turbo product codes with extended BCH codes using zero padding and shortening the row and/or column to adapt a next-generation (NG) Digital Video Broadcasting-Return Channel by Satellite (DVB-RCS) system. In addition, in order to make various coding rates for the required standard, we used different coding rates between row and column codes. At a bit error rate (BER) of 10-4 the performance is better at around 1.5-2 dB compared to soft-based extended BCH codes at the same coding rates.

Analysis of early stopping method applied to horizontal shuffling scheduling scheme of DVB-S2 LDPC code

In this paper, we verify that a horizontal shuffling scheduling (HSS) LDPC decoding scheme makes its LLR value converge faster than a Flooding Scheduling (FS) scheme. Also, we analyze the effects of channel adaptive early termination (CAET) method on HSS decoding scheme. Simulation result shows that combining the CAET method and HSS scheme effectively reduces the average number of iterations for LDPC decoding process with acceptable BER performance

A transmission capacity enhancement of the CDM-based satellite DMB system

After the launch of Satellite Digital Multimedia Broadcasting (S-DMB) service in Korea, there was a requirement to have more channels to accommodate more bandwidth-requiring applications. We designed a new architecture to provide the system with more channel capacity while maintaining the current performance as much as possible. We took a hierarchical modulation technology used for the DVB-S2 standard. A number of combinations of modulation parameters and FEC modes have been simulated for the evaluation of technical feasibility of the proposed structure. Also investigations were carried out to assess the impact to current service performance. It was found that a 16200-bit LDPC with hierarchical modulation could give additional channel capacity while keeping the current quality of service for selected CODEC and code rates (Int. J. Satellite Commun. Networks 2004; 22). Though 1ldB degradation of BER to the existing service was resulted by this approach, but no perceptional service degradation was expected since current link margin is larger than 3ldB. We found that about 36% of capacity enhancement can be achievable by the hierarchical modulation with proper CODEC selection. Additional degradation, however, may be encountered in mobile environment due to the multipath channel in spite of its performance immunity to the Doppler effect. Copyright