Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài:Link Adaptation for Framed Multimedia Data Transmission over a DS-CDMA Communication System | EURASIP Journal on Applied Signal Processing 2005 2 153-166 2005 Hindawi Publishing Corporation Link Adaptation for Framed Multimedia Data Transmission over a DS-CDMA Communication System Charly Poulliat ETIS Laboratory UMR 8051 ENSEA University of Cergy-Pontoise CNRS 6 Avenue du Ponceau 95014 Cergy-Pontoise Cedex France Email poulliat@ Inbar Fijalkow ETIS Laboratory UMR 8051 ENSEA University of Cergy-Pontoise CNRS 6 Avenue du Ponceau 95014 Cergy-Pontoise Cedex France Email fijalkow@ David Declercq ETIS Laboratory UMR 8051 ENSEA University of Cergy-Pontoise CNRS 6 Avenue du Ponceau 95014 Cergy-Pontoise Cedex France Email declercq@ Received 31 July 2003 Revised 17 May 2004 In the context of frame-based multimedia wireless transmission a link adaptation strategy is proposed assuming that the source decoder may accept some remaining errors at the output of the channel decoder. Based on a target mean bit error rate for erroneous frames a minimum bit-energy-to-equivalent-noise ratio is chosen. Under this constraint a new link adaptation criterion is proposed the maximization of the minimum user s information rate through dynamic spreading gain and power control allowing to guarantee a transmission for each and every user. An analytical solution to this constrained optimization problem is proposed and its performance is studied in a Rayleigh-fading environment. Keywords and phrases resource allocation management link adaptation rate and power adaptation multirate DS-CDMA. 1. INTRODUCTION The framework of the paper is the transmission of multimedia data through a wireless multiuser communication system such as the direct-sequence code-division multiple access DS-CDMA . The main feature of the transmitted data is that we consider a packet-mode transmission system. On one hand the source coder and decoder are communicating with compressed data packets and on the other hand DS-CDMA communication systems such as the Universal Mobile Telecommunication .
