Truyền dữ liệu qua kênh thoại GSM với CD-FSK
Abstract— GSM Voice Channel used hybrid based on Linear Predictive Coding Codec. It also used some technical in speech processing as VAD (Voice Activity Detectors), AGC (Automatic Gain Control). As a result, audio signals that are not voice - like are greatly distorted because they violate speech signal properties assumed by the underlying codecs. In this paper, discuss about GSM voice channel and presents the approach for transmit normal data over that channel with: Constant - Differential frequency shift keying technique.
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Tài liệu tham khảo [1]. Friedhelm Hillebrand (2002), “GSM and UMTS: The Creation of Global Mobile Communication”, by John Wiley & Sons, Ltd; ISBN 0-4708-4322-5. [2]. La Hữu Phúc, “Truyền dữ liệu qua kênh thoại GSM bằng tiếng nói tổng hợp”, Tạp chí nghiên cứu KHKT&CNQS, số 9,10-2010, Tr 62-68. [3]. A. Kondoz (2004), “Digital Speech: Coding for Low bit rate Communications System”, John Wiley & Sond Ltd, Second Editor ISBN: 0 470 87008 7. [4]. ETSI. “Digital cellular telecommunications system (Phase 2+) (GSM)”; “ANSIC code for the GSM Enhanced Full Rate (EFR) speech codec” (GSM 06.53 version 8.0.1 Release 1999), ETSI EN 300 724, November 2000. [5]. N.N. Katugampala, K.T. Al-Naimi, S. Villette, and A.M. Kondoz (2004), “Real time data transmission over gsm voice channel for secure voice & data applications” In 2nd IEE Secure Mobile Communications Forum (2004). [6]. Peter Vary, Rainer Martin (2006), “Digital Speech Transmission: Enhancement, Coding and Error Concealment”, John Wiley & Sond Ltd, ISBN: 0 471 56018 9. [7]. “Hermer: Data Transmission over Unknown Voice Channels”. Https://cs.nyu.edu/~jchen/publications/ com31a-dhananjay.pdf. |
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