Yuji Shinohara

Low-Density Parity-Check Codes for ATSC 3.0

In this paper, we introduce the overview and detailed structure of low-density parity-check (LDPC) codes, which are adopted for the physical layer standard of Advanced Television Systems Committee (ATSC) 3.0. As one of the features to mitigate channel errors efficiently, LDPC codes are used as a main part of forward error correction scheme within the bit interleaved coded modulation chain. This paper presents two different structures of LDPC codes in the ATSC 3.0 standard: 1) irregular repeat accumulate structure and 2) multi-edge type structure. After the detailed encoding methods for the two structures are introduced, the performance results including comparison studies with other broadcasting standards such as DVB-T2 and DVB-S2 are shown.

Application of Turbo Codes to High-Density Optical Disc Storage Using 17PP Code

We have previously proposed a novel trellis decoding technique for soft-output decoding of the 17PP code. Using this technique, we have developed a turbo-coded 17PP system, and showed improvement in the bit error rate (BER) in an additive white Gaussian noise (AWGN) channel by simulation. In this paper, we describe an optimized trellis of the 17PP code that has only 15 states and 53 branches. It is well known that a partial response (PR) channel can be regarded as a convo-lutional code with the trellis structure. Therefore we merged the PR1221 trellis into the 17PP trellis, which we call the PR17PP trellis, and similarly optimized this trellis. With the soft-in soft-out (SISO) decoders using this PR17PP trellis, it is experimentally confirmed that the turbo-coded 17PP system effectively increases the user capacity of an optical disc.

A High Performance and Programmable Decoder VLSI for Structured LDPC Codes

We have developed a high performance and programmable LDPC decoder VLSI for decoding structured LDPC codes. In this paper, the architecture of the decoder and the structured parity check matrices are described along with the quantization method. We adopt floating point (FP) quantization method in check node processors so as to shrink down the complexity of look up tables (LUTs) of the Gallager function, and avoid performance degradation. Finally, simulation results show that the FP quantization method achieves high performance for wide range of code rates

An optimization method for designing high rate and high performance SCTCM systems with in-line interleavers

We present a method for designing high-rate, high-performance SCTCM (serially concatenated trellis coded modulation) systems with in-line interleavers. Using in-line EXIT charts and ML performance analysis, we develop criteria for choosing constituent codes and optimization methods for selecting the best ones. To illustrate our methods, we show that an optimized SCTCM system with an in-line interleaver for rate r = 5/6 and 64QAM has better performance than other turbo-like TCMs with the same parameters.

Terrestrial broadcast system using preamble and frequency division multiplexing

Broadcast systems based on FDM (Frequency Division Multiplex) have the advantage of near continuous demodulation of the broadcast signal, allowing accurate and continuous tracking of channel conditions which is particularly useful for mobile reception. This has been employed in the ISDB-T standard used in Japan, Brazil and other countries. However, as designed in ISDB-T the broadcast signal lacks the ability to send system parameters such as FFT size, GI size and so on before the receiver begins demodulation. The receiver must blindly estimate such system parameters before it can read the other detailed parameter information using the TMCC pilot carriers. This takes time, usually one frame or longer. This paper proposes a next generation FDM system which enables the original advantages of FDM to be retained, while allowing additional advantages by employing an additional small signal (Preamble 1) which imparts essential information such as FFT size, GI size and pilot pattern to the receiver to enable immediate demodulation of the broadcast signal based on known parameters rather than blind estimation. Following demodulation of the first preamble, demodulation of the second preamble (Preamble 2) allows immediate knowledge of the all subsequent parameters contributing to faster demodulation of the overall signal.