Title :
Delay estimation of code-spread CDMA systems
Author :
Malmsten, Fredrik ; Ottosson, Tony ; Ström, Erik G.
Author_Institution :
Dept. of Signals & Syst., Chalmers Univ. of Technol., Goteborg, Sweden
Abstract :
Delay estimation of a code-spread code division multiple access (CS-CDMA) system using low-rate maximum free distance (MFD) convolutional codes for bandwidth expansion is studied. Using the repetitive structure of the low-rate MFD codes, the codewords are first permuted using a criterion based on the Cramer-Rao bound that results in good delay estimation properties. Thereafter, an approximate maximum-likelihood estimator that jointly estimate the channel gain, the codewords and the delay is used. Using the derived algorithm we show that it is in fact possible to estimate the delay in a code-spread system
Keywords :
AWGN; channel coding; code division multiple access; convolutional codes; delay estimation; land mobile radio; maximum likelihood estimation; radiofrequency interference; spread spectrum communication; AWGN channel; Cramer-Rao bound; DS-CDMA; additive white Gaussian noise; approximate maximum-likelihood estimator; bandwidth expansion; channel gain estimation; code-spread CDMA systems; codewords; convolutional codes; delay estimation; direct sequence code division multiple access; low-rate channel codes; low-rate maximum free distance codes; mobile radio; multiple access interference; repetition encoder; repetitive structure; scrambling sequence; spreading sequence; AWGN; Additive white noise; Bandwidth; Character generation; Clocks; Delay estimation; Maximum likelihood estimation; Multiaccess communication; Repeaters; Throughput;
Conference_Titel :
Vehicular Technology Conference Proceedings, 2000. VTC 2000-Spring Tokyo. 2000 IEEE 51st
Conference_Location :
Tokyo
Print_ISBN :
0-7803-5718-3
DOI :
10.1109/VETECS.2000.851628
