Title :
A modified acquisition method with code-orthogonalizing filters in asynchronous DS/CDMA
Author :
Tachikawa, Shinichi ; Nakano, Chiyo ; Tahara, Masaaki ; Hamamura, Masanori
Author_Institution :
Nagaoka Univ. of Technol., Niigata, Japan
Abstract :
We present synchronous acquisition methods using code-orthogonalizing filters (COFs) in asynchronous direct sequence (DS)/CDMA. In the systems, the tap coefficients of the COF are controlled to orthogonalize to all users sequences including the desired user´s spreading sequence. Several probable synchronous phases are selected by using the difference of correlation function value between the tap coefficients and the desired user´s sequence for each phase. Then, the most probable synchronous phase is decided from these phases by a previous proposed precise acquisition system. By computer simulations, we show the improvements of the average acquisition time under several conditions
Keywords :
code division multiple access; correlation methods; digital radio; filtering theory; land mobile radio; multiuser channels; sequences; spread spectrum communication; synchronisation; asynchronous DS/CDMA; average acquisition time; code division multiple access; code-orthogonalizing filters; computer simulations; correlation function; digital mobile radio communication system; modified acquisition method; probable synchronous phases; synchronous acquisition methods; tap coefficients; user spreading sequence; AWGN; Computer simulation; Convergence; Correlators; Electronic mail; Filters; Interference; Mobile communication; Multiaccess communication; Power system modeling;
Conference_Titel :
Spread Spectrum Techniques and Applications, 2000 IEEE Sixth International Symposium on
Conference_Location :
Parsippany, NJ
Print_ISBN :
0-7803-6560-7
DOI :
10.1109/ISSSTA.2000.876507
