Tuyển tập các báo cáo nghiên cứu về hóa học được đăng trên tạp chí hóa hoc quốc tế đề tài : Blind recovery of k/n rate convolutional encoders in a noisy environment | Marazin et al. EURASIP Journal on Wireless Communications and Networking 2011 2011 168 EURASIP Journal on . http content 2011 1 i68 Wireless Communications and Networking a SpringerOpen Journal RESEARCH Open Access Blind recovery of k n rate convolutional encoders in a noisy environment Melanie Marazin1 2 Roland Gautier1 2 and Gilles Burel1 2 Abstract In order to enhance the reliability of digital transmissions error correcting codes are used in every digital communication system. To meet the new constraints of data rate or reliability new coding schemes are currently being developed. Therefore digital communication systems are in perpetual evolution and it is becoming very difficult to remain compatible with all standards used. A cognitive radio system seems to provide an interesting solution to this problem the conception of an intelligent receiver able to adapt itself to a specific transmission context. This article presents a new algorithm dedicated to the blind recognition of convolutional encoders in the general k n rate case. After a brief recall of convolutional code and dual code properties a new iterative method dedicated to the blind estimation of convolutional encoders in a noisy context is developed. Finally case studies are presented to illustrate the performances of our blind identification method. Keywords intelligent receiver cognitive radio blind identification convolutional code dual code 1 Introduction In a digital communication system the use of an error correcting code is mandatory. This error correcting code allows one to obtain good immunity against channel impairments. Nevertheless the transmission rate is decreased due to the redundancy introduced by a correcting code. To enhance the correction capabilities and to reduce the impact of the amount of redundancy introduced new correcting codes are always under development. This means that communication systems are in perpetual evolution. Indeed it is becoming more and
