• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.15 no.4
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• pp.230-236
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• 2022

In this paper, we propose an efficient concatenated code for both random and ISI errors on diffusion-based molecular communication channels. The proposed concatenated code was constructed by combining the ISI-mitigating code designed for ISI mitigation and the ISI-Hamming code strong against random errors, and the BER(bit error rate) performance was analyzed through simulation. In the case of the above M=1,200 channel environment, it was found that the error rate performance of the concatenated code follows the error rate performance of the ISI-mitigating code, which is strong against ISI, and follows the error rate performance of the ISI-Hamming code, which is strong against random errors, in the channel environment below M=600. In M=600~1,200, the concatenated code shows the best error rate performance among those of three codes, which is analyzed because it can correct both random errors and errors caused by ISI. In the following cases of below M=800, it can be seen that the error rate of the concatenated code and the ISI-mitigating code shows an error rate difference of about 1.0×10^-1 on average.

• Proceedings of the KIEE Conference
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• 1987.07b
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• pp.874-877
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• 1987

In this paper a DPLL circuit realizable by digital IC's is propose and the principles of general DPLL are described. An all Digital phase locked loop is designed, analyzed, and tested. In particular, the approach of invoking Gaussian assumption on the decision variable and based on S.O.Rices theory is used. As a performance of the above PLL detector operating on low data rate FSK is given and demonsrtated to be FSK reception.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.06a
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• pp.454-458
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• 2005

In this paper we analyzed the performance of data transmission using BPSK modulation. The system performances were evaluated by the experiments in water tank. As a result we showed the influences of reverberation due to the multipath. In order to simplify the experiment procedure the channel coding etc. were omitted. The experimental result shows that the maximum transmission data rate in used water tank is about 350 bps at bit error rate of $10^{-3}$.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2011.11a
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• pp.78-81
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• 2011

In this paper, we propose an additional data transmission scheme using multiple-antennas with backward compatibility for legacy ATSC (Advanced Television Systems Committee) terrestrial DTV (digital television) receivers. The proposed scheme improves the data rate and bit error rate performance compared to the conventional single antenna transmission scheme for additional data. Also, the proposed scheme guarantees backward compatibility for legacy ATSC DTV receivers.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2011.11a
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• pp.247-250
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• 2011

In this paper, we propose an additional data transmission scheme using multiple-antennas with backward compatibility for legacy ATSC (Advanced Television Systems Committee) terrestrial DTV (digital television) receivers. The proposed scheme improves the data rate and bit error rate performance compared to the conventional single antenna transmission scheme for additional data. Also, the proposed scheme guarantees backward compatibility for legacy ATSC DTV receivers.

• Journal of Communications and Networks
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• v.9 no.3
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• pp.265-273
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• 2007

This paper expands an analytical performance model of 802.11 to accurately estimate throughput and energy demand of 802.11-based wireless sensor network (WSN) when sensor nodes employ Reed-Solomon (RS) codes, one of block forward error correction (FEC) techniques. This model evaluates these two metrics as a function of the channel bit error rate (BER) and the RS symbol size. Since the basic recovery unit of RS codes is a symbol not a bit, the symbol size affects the WSN performance even if each packet carries the same amount of FEC check bits. The larger size is more effective to recover long-lasting error bursts although it increases the computational complexity of encoding and decoding RS codes. For applying the extended model to WSNs, this paper collects traffic traces from a WSN consisting of two TIP50CM sensor nodes and measures its energy consumption for processing RS codes. Based on traces, it approximates WSN channels with Gilbert models. The computational analyses confirm that the adoption of RS codes in 802.11 significantly improves its throughput and energy efficiency of WSNs with a high BER. They also predict that the choice of an appropriate RS symbol size causes a lot of difference in throughput and power waste over short-term durations while the symbol size rarely affects the long-term average of these metrics.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.38 no.11
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• pp.41-48
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• 2001

The exact general bit error rate (TIER) expression of M-ary square quadrature amplitude modulation (QAM) for arbitrary M has not been derived so far. In this paper, a generalized closed-form expression for the BER performance of M-ary square QAM with Gray code bit mapping is derived and analyzed in the presence of additive white Gaussian noise (AWGN) channel. The derivation is based on the consistency of the format in signal constellation o[ Gray coding and it has been derived from the results for M-16, 64, and 256.

• Journal of Astronomy and Space Sciences
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• v.37 no.1
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• pp.11-18
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• 2020

Satellite optical communication has gained significant attention owing to its many quality features (e.g., a larger bandwidth, license free spectrum, higher data rate, and better security) compared to satellite microwave communication. Various experiments have been performed during many space missions to demonstrate and characterize inter-satellite links, downlinks, and uplinks. Korea has also planned to establish an experimental communication system using a geostationary earth orbit (GEO) satellite and the Geochang station as an optical ground station for low Earth orbit (LEO)-to-ground optical relay links. In this study, the performance of inter-satellite communication links and downlinks was investigated for the new Korean experimental communication system in terms of link margin, bit error rate (BER), and channel capacity. In particular, the performance of the inter-satellite links was analyzed based on the receiving apertures and the transmitting power, while that of the downlink was analyzed in terms of atmospheric turbulence conditions and transmitting power. Finally, we discussed two system parameters of receiving aperture and transmitting power to meet the three criteria of link margin, BER, and channel capacity.

• Journal of the Optical Society of Korea
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• v.20 no.2
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• pp.276-282
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• 2016

A 2 Gbit/s visible-light communication (VLC) scheme using time-frequency color-clustered (TFCC) multiple-input multiple-output (MIMO) based on blue, cyan, yellow, and red (BCYR) light-emitting diodes (LEDs) is presented. In the proposed scheme, BCYR LEDs are employed to form four different color clusters. Data transmission using the four color clusters is performed in MIMO, so that the scheme achieves a very high speed of data transmission. Moreover, the scheme employs the TFCC strategy to yield high performance in terms of bit error rate (BER). TFCC operates in such a way that the original data and the two delayed versions of the data are multiplied by orthogonal frequencies and then transmitted using a specific color of the BCYR LED. In the receiver, color filters are employed to detect the data transmitted from the desired cluster. Selection combining (SC) is also performed to yield a diversity effect within each color cluster, to further improve the performance. Performance evaluation demonstrates that the proposed TFCC MIMO VLC offers a data rate of 2 Gbit/s and a bit error rate of 4×10^-5, at an E_b/N_o value of merely 3 dB.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.16 no.11
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• pp.1054-1062
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• 1991

In this paper a communication system using direct sequence spread spectrum (DS/SS) technique is constructed to transmit burst format data over power line channel with impulsive noise and narrowband interferences. Fast code synchronization is acquired by digital matched filter and data decision is accomplished by sampling pulses. In order to examine the performance of the power line communication system, but error rate and packet loss rate are measured over the simulation channel with various noise sources. When the packet composed of 1-bit preamble and 63-bit data is transmitted under very high burst impulsive noise, the bit error rate is about 10$^3$-10$^4$ and the packet loss rate is below 0.07.