Title :
Extended total weighted squared correlation signature sequences of DS-CDMA systems in multipath channels
Author_Institution :
Dept. of Electr. & Comput. Eng., Texas Univ., San Antonio, TX, USA
Abstract :
We analyze the extended total weighted squared correlation (ETWSC) for a given signature sequence set used in slow flat multipath channels and in the presence of colored noise. extended total square correlation (ETSC) and total squared correlation (TSC) are particular cases of ETWSC and are considered as well. The main results of this paper are: 1) the conditions on the channel such that the received multipath sequences are WBE (Welch bound Equality) sequences and 2) an iterative distributed method for obtaining real sequences that meet the Welch´s lower bound on ETWSC. The method is based on majorization theory decreasing the weighted Frobenius norm associated with users´ Sylvester channel matrices and noise covariance matrix. Numerical results for overloaded DS-CDMA systems are presented in order to support our analysis.
Keywords :
code division multiple access; correlation theory; covariance matrices; iterative methods; multipath channels; random sequences; spread spectrum communication; DS-CDMA system; Welch bound equality sequence; channel matrice; colored noise; extended total weighted squared correlation signature sequence; iterative distributed method; majorization theory; multipath channel; multipath sequence; noise covariance matrix; Colored noise; Covariance matrix; Delay; Intersymbol interference; Iterative methods; Multiaccess communication; Multipath channels; Neural networks; Signal processing;
Conference_Titel :
Global Telecommunications Conference, 2003. GLOBECOM '03. IEEE
Print_ISBN :
0-7803-7974-8
DOI :
10.1109/GLOCOM.2003.1258429
