• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.4 no.6
• /
• pp.1116-1132
• /
• 2010

In this paper, a new forward error correction (FEC) protocol is proposed for point-to-multipoint satellite links. Link-layer error control protocols in point-to-multipoint satellite links impose several problems such as unreliability and receiver-heterogeneity. To resolve the problem of heterogeneous error rates at different receivers, the proposed scheme exploits multiple multicast channels to which each receiver tunes. The more channels a receiver tunes to, the more powerful error correcting capability it achieves. Based on its own channel condition, each receiver tunes to as many channels as it needs, which prevents from receiving unwanted parities. Furthermore, each receiver saves the decoding time, processing overhead, and processing energy. Performance evaluation shows that the proposed scheme guarantees the target PER while saving energy. The proposed technique is highly adaptive to the channel variation with respect to the throughput efficiency, and provides scalable PER and throughput efficiency.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.46 no.11
• /
• pp.48-55
• /
• 2009

This paper presents a high-speed Forward Error Correction (FEC) architecture based on three-parallel Reed-Solomon (RS) decoder for next-generation 100-Gb/s optical communication systems. A high-speed three-parallel RS(255,239) decoder has been designed and the derived structure can also be applied to implement the 100-Gb/s RS-FEC architecture. The proposed 100-Gb/s RS-FEC has been implemented with 0.13-${\mu}m$ CMOS standard cell technology in a supply voltage of 1.2V. The implementation results show that 16-Ch. RS-FEC architecture can operate at a clock frequency of 300MHz and has a throughput of 115-Gb/s for 0.13-${\mu}m$ CMOS technology. As a result, the proposed three-parallel RS-FEC architecture has a much higher data processing rate and low hardware complexity compared with the conventional two-parallel, three-parallel and serial RS-FEC architectures.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.32 no.10C
• /
• pp.950-958
• /
• 2007

This paper presents an efficient packet loss resilient scheme for real-time video transmission over the Internet. By analyzing the temporal and spatial dependencies in inter- and intra-frames, we assign forward error correction codes (FEC) across video packets for minimizing the effect of error concealment and error propagation from packet loss. To achieve optimal allocation of FEC codes, we formulate the effect of packet loss on video quality degradation as packet distortion model. Then we propose an unequal FEC assignment scheme with low complexity based on packet correction rate, which uses the packet distortion model and includes channel status information. Simulation results show that the proposed FEC assignment scheme gives substantial improvement for the received video quality in packet lossy networks. Furthermore the proposed scheme achieves relatively smaller degradation of video quality with higher packet loss rates.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.26 no.11A
• /
• pp.1803-1811
• /
• 2001

In this paper, Forward Error Correction(FEC) that is satisfied with ITU-T Recommendation J.83, Annex B(North American Data Over Cable Service Interface Specifications(DOCSIS) for Multimedia Cable Network System(MCNS)) is analyzed. The FEC consist of Reed-Solomon(RS) layer, interleaving layer, randomization layer, and trellis coded modulation(TCM) layer. The effects of quantization of input symbol and of trace-back depth in the Viterbi decoder are simulated over AWGN channels.

• The Transactions of the Korea Information Processing Society
• /
• v.7 no.12
• /
• pp.3944-3951
• /
• 2000

In this paper, we propose the new FEC(Forward Error Correction) code method, so called RCNC(Random Connection Node Convolutional) code with security property. Recently, many wireless communication systems, which can prouide integrated semices of various media types and hil rales, are required to haue the ability of secreting information and error correclion. This code system is a kind qf conuolulional code, but it Ius various code formats as each node is connected differently. And systems hy using RCNC codes haue all. ability of error correction as well as information protection. We describe the principle of operating RCNC codes, including operation examples. In this paper, we also show the peiformance of BER(Bit Error Rate) and verify authority of network system with computer simulation.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.19 no.10
• /
• pp.2247-2255
• /
• 2015

In very shallow water acoustic communication channel, underwater acoustic (UWA) communication signal is observed as frequency selective fading signal due to time-varying multipath. This induces a time and frequency dependent inter-symbol-interference (ISI) and degrades the UWA system performance. There is no study about how the performances of the error correction codes are related to a multipath fading statistics in very shallow water. In this study, the characteristics of very shallow water multipath fading channel is analyzed and the performances of two different forward error correction (FEC) codes are compared. The convolution code (CC) and Reed-Solomon (RS) code are adopted. Sea experimental results show that RS code is better choice than CC in frequency selective channel with fading.

• Journal of Broadcast Engineering
• /
• v.18 no.6
• /
• pp.872-883
• /
• 2013

In this paper, we design and analyze performance of Exclusive-OR based FEC (Forward error correction) system to deploy SVC video transmission service over packet-loss prone IP network. In the designed system, we adopt standard compliant Exclusive-OR based FEC scheme and apply it to be appropriate to the hierarchical layer structure of SVC video. To verify the performance of the designed Exclusive-OR based FEC system for SVC video transmission, we employ NIST-NET based transport simulator. By the SVC video transmission using the NIST-NET based simulator, we confirm the error resilient transmission performance of the designed Exclusive-OR based FEC system.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.27 no.6
• /
• pp.821-828
• /
• 1990

A forward error correction (FEC) technique is presented for speech data in 16 Kbps digital mobile communications. 14Kbps SBC-APCM(AQB) and QPSK are used as speech coding and modulation techniques, respectively. Because each bit in a speech data block had different importance, applying FEC to speech data bit-selectively in more effective than applying FEC to all speech data equally. To select bits in a speech data block to be protected by FEC the bit error sensitivity of each bit is computed. For a few BCH and Reed-Solomon codes used as bit-selective FEC the performance of the coding technique is computed.

• Proceedings of the KIEE Conference
• /
• 2007.10a
• /
• pp.387-388
• /
• 2007

IEEE 802.15.4a의 UWB(ultra-wide band) 방식에서 PHY(physical layer) 시스템에 사용되는 FEC(forward error correction)는 RS(Reed-Solomon) 조직적(systematic) 블록 부호와 1/2의 부호율을 가진 조직적 길쌈 부호의 연접 형태로 이루어져 있다.[1] UWB 신호를 이용한 시스템은 연속적이지 않은 임펄스(impulse) 기반의 신호를 사용하기 때문에 정밀도 면에서 뛰어난 장점을 가진다. 본 논문에서는 IEEE P802.15.4a 표준에 명시되어 있는 FEC를 구현하여 AWG(adaptive white gaussian noise) 채널에서의 SNR(signal to noise ratio)에 따른 BER(bit error rate)을 구함으로써 성능을 분석하였다. 실험에서의 정확한 결과를 얻기 위해 15.4a의 UWB에서의 변조 방식에 따라 신호를 변조한 후 잡음을 삽입하여 결과를 도출하였다.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1996.04a
• /
• pp.483-487
• /
• 1996

We consider the estimation of the position and orientation of 6 DOF motion bed (Stewart platform) from the measured cylinder length. The solution of forward kinematics is not solved yet as a useful realtime application tool because of the complity of the equation with multiple solutiple solutions. Hence we suggest an algorithm for the estimation of forward kinematics solution using Luenberger observer withnonlinear error correction term. The Luenberger observer withlinear model shows that the estimation error does not go to zero in steadystate due to the linearization error of the dynamic model. Hence the linear observer is modified using nonlinear measurement error equation and we prove thd practical stability of the estimation error dynamics of the proposed observer using lyapunov function.