Deteksi dan Koreksi Multi Bit Error dengan Partition Hamming Code

Mengirimkan data dari pengirim ke penerima merupakan salah satu bentuk komunikasi. Data dapat dikirim menggunakan saluran nirkabel ataupun saluran kabel, pada saat proses data dikirimkan dapat terjadi error yang disebabkan oleh saluran yang bising. Error yang terjadi dapat merusak data yang dikirim, error tersebut dapat berupa single bit error atau multi bit error. Error dapat diperbaiki dengan menerapkan error control coding. Hamming code merupakan salah satu contoh teknik error control coding yang dapat mendeteksi dan mengkoreksi error. Pada penelitian ini dianalisa metode untuk mendeteksi dan mengkoreksi multi bit error pada pesan yang dikirimkan menggunakan partition hamming code. Sebelum data dikirim ke penerima, pengirim membuat pola partition bit pesan yang lebih kecil dari hamming code (7,4) dan menambahkan bit parity dalam semua blok pesan yang dipecah sehingga menjadi sebuah codeword baru. Partition digunakan agar penerima mudah dalam mendeteksi dan mengkoreksi multi bit error

DETEKSI DAN KOREKSI MULTI BIT ERROR DENGAN PARTITION HAMMING CODE

Mengirimkan data dari pengirim ke penerima merupakan salah satu bentuk komunikasi. Data dapat dikirim menggunakan saluran nirkabel ataupun saluran kabel, pada saat proses data dikirimkan dapat terjadi error yang disebabkan oleh saluran yang bising. Error yang terjadi dapat merusak data yang dikirim, error tersebut dapat berupa single bit error atau multi bit error. Error dapat diperbaiki dengan menerapkan error control coding. Hamming code merupakan salah satu contoh teknik error control coding yang dapat mendeteksi dan mengkoreksi error. Pada penelitian ini dianalisa metode untuk mendeteksi dan mengkoreksi multi bit error pada pesan yang dikirimkan menggunakan partition hamming code. Sebelum data dikirim ke penerima, pengirim membuat pola partition bit pesan yang lebih kecil dari hamming code (7,4) dan menambahkan bit parity dalam semua blok pesan yang dipecah sehingga menjadi sebuah codeword baru. Partition digunakan agar penerima mudah dalam mendeteksi dan mengkoreksi multi bit error

Error mitigation using RaptorQ codes in an experimental indoor free space optical link under the influence of turbulence

This paper is a postprint of a paper submitted to and accepted for publication in [journal] and is subject to Institution of Engineering and Technology Copyright. The copy of record is available at IET Digital LibraryIn free space optical (FSO) communications, several factors can strongly affect the link quality. Among them, one of the most important impairments that can degrade the FSO link quality and its reliability even under the clear sky conditions consists of optical turbulence. In this work, the authors investigate the generation of both weak and moderate turbulence regimes in an indoor environment to assess the FSO link quality. In particular, they show that, due to the presence of the turbulence, the link experiences both erasure errors and packet losses during transmission, and also compare the experimental statistical distribution of samples with the predicted Gamma Gamma model. Furthermore, the authors demonstrate that the application of the RaptorQ codes noticeably improves the link quality decreasing the packet error rate (PER) by about an order of magnitude, also offering in certain cases an error-free transmission with a PER of ∼10−2 at Rytov variance value of 0.5. The results show that the recovery rate increases with the redundancy, the packet length and the number of source packets, and it decreases with increasing data rates.This work was supported by the European Space Agency under grant no. 5401001020. We are very grateful to Dr. E. Armandillo for enlightening discussions. This research project also falls within the frame of COST ICT Action IC1101 - Optical Wireless Communications - An Emerging Technology (OPTICWISE). J. Perez's work is supported by Spanish MINECO Juan de la Cierva JCI-2012-14805.Pernice, R.; Parisi, A.; Ando, A.; Mangione, S.; Garbo, G.; Busacca, AC.; Perez, J.... (2015). Error mitigation using RaptorQ codes in an experimental indoor free space optical link under the influence of turbulence. IET Communications. 9(14):1800-1806. https://doi.org/10.1049/iet-com.2015.0235S18001806914Tsukamoto, K., Hashimoto, A., Aburakawa, Y., & Matsumoto, M. (2009). The case for free space. IEEE Microwave Magazine, 10(5), 84-92. doi:10.1109/mmm.2009.933086Paraskevopoulos, A., Vučić, J., Voss, S.-H., Swoboda, R., & Langer, K.-D. (2010). Optical Wireless Communication Systems in the Mb/s to Gb/s Range, Suitable for Industrial Applications. IEEE/ASME Transactions on Mechatronics, 15(4), 541-547. doi:10.1109/tmech.2010.2051814Ghassemlooy, Z., Le Minh, H., Rajbhandari, S., Perez, J., & Ijaz, M. (2012). Performance Analysis of Ethernet/Fast-Ethernet Free Space Optical Communications in a Controlled Weak Turbulence Condition. Journal of Lightwave Technology, 30(13), 2188-2194. doi:10.1109/jlt.2012.2194271Ciaramella, E., Arimoto, Y., Contestabile, G., Presi, M., D’Errico, A., Guarino, V., & Matsumoto, M. (2009). 1.28-Tb/s (32 $\times$ 40 Gb/s) Free-Space Optical WDM Transmission System. IEEE Photonics Technology Letters, 21(16), 1121-1123. doi:10.1109/lpt.2009.2021149Parca, G. (2013). Optical wireless transmission at 1.6-Tbit/s (16×100  Gbit/s) for next-generation convergent urban infrastructures. Optical Engineering, 52(11), 116102. doi:10.1117/1.oe.52.11.116102Hulea, M., Ghassemlooy, Z., Rajbhandari, S., & Tang, X. (2014). Compensating for Optical Beam Scattering and Wandering in FSO Communications. Journal of Lightwave Technology, 32(7), 1323-1328. doi:10.1109/jlt.2014.2304182Ghassemlooy, Z., Popoola, W. O., Ahmadi, V., & Leitgeb, E. (2009). MIMO Free-Space Optical Communication Employing Subcarrier Intensity Modulation in Atmospheric Turbulence Channels. Communications Infrastructure. Systems and Applications in Europe, 61-73. doi:10.1007/978-3-642-11284-3_7Garcia-Zambrana, A. (2007). Error rate performance for STBC in free-space optical communications through strong atmospheric turbulence. IEEE Communications Letters, 11(5), 390-392. doi:10.1109/lcomm.2007.061980Abou-Rjeily, C. (2011). On the Optimality of the Selection Transmit Diversity for MIMO-FSO Links with Feedback. IEEE Communications Letters, 15(6), 641-643. doi:10.1109/lcomm.2011.041411.110312García-Zambrana, A., Castillo-Vázquez, C., & Castillo-Vázquez, B. (2010). Rate-adaptive FSO links over atmospheric turbulence channels by jointly using repetition coding and silence periods. Optics Express, 18(24), 25422. doi:10.1364/oe.18.025422Andò, A., Mangione, S., Curcio, L., Stivala, S., Garbo, G., Pernice, R., & Busacca, A. C. (2013). Recovery Capabilities of Rateless Codes on Simulated Turbulent Terrestrial Free Space Optics Channel Model. International Journal of Antennas and Propagation, 2013, 1-8. doi:10.1155/2013/692915MacKay, D. J. C. (2005). Fountain codes. IEE Proceedings - Communications, 152(6), 1062. doi:10.1049/ip-com:20050237Shokrollahi, A. (2006). Raptor codes. IEEE Transactions on Information Theory, 52(6), 2551-2567. doi:10.1109/tit.2006.874390Anguita, J. A., Neifeld, M. A., Hildner, B., & Vasic, B. (2010). Rateless Coding on Experimental Temporally Correlated FSO Channels. Journal of Lightwave Technology, 28(7), 990-1002. doi:10.1109/jlt.2010.2040136Wang, N., & Cheng, J. (2010). Moment-based estimation for the shape parameters of the Gamma-Gamma atmospheric turbulence model. Optics Express, 18(12), 12824. doi:10.1364/oe.18.012824Zvanovec, S., Perez, J., Ghassemlooy, Z., Rajbhandari, S., & Libich, J. (2013). Route diversity analyses for free-space optical wireless links within turbulent scenarios. Optics Express, 21(6), 7641. doi:10.1364/oe.21.007641Pernice, R., Perez, J., Ghassemlooy, Z., Stivala, S., Cardinale, M., Curcio, L., … Parisi, A. (2015). Indoor free space optics link under the weak turbulence regime: measurements and model validation. IET Communications, 9(1), 62-70. doi:10.1049/iet-com.2014.043

A Multi-Burst Sliding Encoding for Mobile Satellite TV Broadcasting

Protection of data against long fading time is one of the greatest challenges posed by a satellite delivery system offering multimedia services to mobile devices like DVB-SH. To deal with this challenge several enhancements and modifications of the existing terrestrial mobile TV (DVB-H) physical and link layers are being considered. These solutions provide the required protection depth but they don't take into account the specificity of mobile handheld devices such as power consumption, memory constraints and chipsets implementation costs. In this report, we propose an innovative algorithm (called Multi Burst Sliding Encoding or MBSE) that extends the DVB-H intra-burst (MPE-FEC) protection to an inter-burst protection so that complete burst losses could be recovered while taking into account the specificity of mobile handheld devices. Based on a clever organisation of the data, our algorithm allows to provide protection against long term fading while still using RS code implemented in DVB-H chipsets. We evaluate the performance of MBSE by both theoretical analysis as well as intensive simulations and experiments. The results also show good performance in terms of protection, battery and memory saving. The MBSE is now under standardisation and it is considered by the DVB Forum as the main solution for the DVB-SH class terminals

Raptor versus Reed Solomon Forward Error Correction codes

Network conditions generally cause errors on network packets. Correction of these errors is in the subject of "Forward Error Correction" Forward error correction is divided into two categories: bit-level forward error correction and packet-level forward error correction. These two categories are unfamiliar. The aim of this study is to making literature comparison of two alternative packet-level forward error correction codes: Raptor and Reed Solomon. Nowadays when packet-level error correction codes are mentioned, these two techniques are remembered. Reed Solomon FEC codes found on the internet so they are tested with different network conditions. Raptor Codes are commercial and not used broadly yet. But several new technologies (MBMS, DVB and etc.) will use Raptor. This study shows the cases, where Raptor and Reed Solomon are appropriate to use

A Study on Techniques for Handling Transmission Error of IPV6 Packets over Fmer Optic Links

Problem identification of the existing error control mechanism is very important to find out a new suitable design to solve the problem of ineffective error control.The identification results become main basic of designing a new mechanism.Hence, the design obtained truly solves the problem accurately