• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.33 no.12C
• /
• pp.1006-1013
• /
• 2008

CZZ (Concatenated Zigzag) Code is a class of fast encodable LDPC codes. In the case that LDPC codes including CZZ codes have short length, short cycles seriously affect the code performance. In this paper, we construct CZZ codes using various degree-2 polynomial interleavers which eliminate cycles of length 4 and through simulation, compare the performance of these CZZ codes and turbo codes in many different fading channels. Especially, quasi-static fading channel, block fading channel, uncorrelated fading channel, and correlated fading channel are considered. Since CZZ codes show similar performance as turbo codes, they can be used in the next generation wireless communication systems.

• The Journal of the Acoustical Society of Korea
• /
• v.27 no.6
• /
• pp.286-295
• /
• 2008

Underwater acoustic communication has multi path error because of reflection by sea-level and sea-bottom. The multipath of underwater channel causes signal distortion and error floor. In this paper, we consider the use of various channel coding schemes such as RS code, convolutional code, cross-layer code and LDPC code in order to compensate the multipath effect in underwater channel. As shown in simulation results, characteristic of multipath error is similar to that of random error, so interleaver has little effect for error correcting. For correcting of error floor by multipath error, it is necessary strong channel codes like LDPC code that is similar to Shannon's limit. And the performance of concatenated codes including RS codes has better performance than using singular channel codes.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.42 no.7 s.337
• /
• pp.27-34
• /
• 2005

Iterative detection (ID) has proven to be a near-optimal solution for concatenated Finite State Machines (FSMs) with interleavers over an additive white Gaussian noise (AWGN) channel. When perfect channel state information (CSI) is not available at the receiver, an adaptive ID (AID) scheme is required to deal with the unknown, and possibly time-varying parameters. The basic building block for ID or AID is the soft-input soft-output (SISO) or adaptive SISO (A-SISO) module. In this paper, Reduced State SISO (RS-SISO) algorithms have been applied for complexity reduction of the A-SISO module. We show that serially concatenated CPM (SCCPM) with AID has turbo-like performance over fading ISI channels and also RS-A-SISO systems have large iteration gains. Various design options for RS-A-SISO algorithms are evaluated. Recently developed density evolution technique is used to analyze RS-A-SISO algorithms. We show that density evolution technique that is usually used for AWGN systems is also a good analysis tool for RS-A-SISO systems over frequency-selective fading channels.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.19 no.10
• /
• pp.1075-1085
• /
• 2008

Recently, it is studied actively that DVB-S2 for mobility standard(DVB-S2M) is combined with DVB-H, DVB-T and conventional DVB-S2 standard for continuous satellite broadcasting and internet service. Especially, overcoming deep fading by tunnel is main subject. For overcoming deep fading, DVB-S2M proposed cross layer system is consist of upper layer and physical layer. Thus, this paper proposed optimal upper layer coding system fixing the physical layer coding under the simulation results by coding methods, train speed, data rate, interleaver size and IP packet size.