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

Volume

3

fYear

2000

fDate

2000

Firstpage

2029

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;

fLanguage

English

Publisher

ieee

Conference_Titel

Vehicular Technology Conference Proceedings, 2000. VTC 2000-Spring Tokyo. 2000 IEEE 51st

Conference_Location

Tokyo

ISSN

1090-3038

Print_ISBN

0-7803-5718-3

Type

conf

DOI

10.1109/VETECS.2000.851628

Filename

851628