Decoupled maximum likelihood multiuser channel estimation for asynchronous DS-CDMA system

Author

Tie, Lok Tiing ; Nallanathan, Arumuga ; Chew, Young Haut

Author_Institution

Nat. Univ. of Singapore, Singapore

fYear

2004

fDate

30 Aug.-2 Sept. 2004

Firstpage

92

Lastpage

96

Abstract

A decoupled maximum likelihood (DEML) channel estimation scheme using recursive matrix computation is proposed for asynchronous code-division multiple access (CDMA) communication systems. The transmission medium is characterized by the presence of multipath components and the parameters of interest are the delays and complex gains of the propagation paths. The DEML estimation is obtained using a training sequence. Followed by DEML estimation, a recursive algorithm is used to find the estimator so as to spread the computational time over each processing window. Lastly, the proposed recursive technique is extended to track a moderate time-varying fading channel using decision feedback. The performance of the derived algorithm is benchmarked against perfect channel knowledge on one hand and DEML estimator without decision feedback on the other hand in terms of bit-error-rate.

Keywords

channel estimation; code division multiple access; delay estimation; error statistics; maximum likelihood estimation; multipath channels; multiuser channels; recursive estimation; spread spectrum communication; time-varying channels; DEML estimation; asynchronous DS-CDMA system; bit error rate; code-division multiple access; complex gains; decision feedback; decoupled maximum likelihood estimation; delays; multipath components; multiuser channel estimation; performance; propagation paths; recursive algorithm; recursive matrix computation; time-varying fading channel; tracking; training sequence; Channel estimation; Delay estimation; Fading; Feedback; Interference; Maximum likelihood estimation; Multiaccess communication; Multiuser channels; Propagation delay; Recursive estimation;

fLanguage

English

Publisher

ieee

Conference_Titel

Spread Spectrum Techniques and Applications, 2004 IEEE Eighth International Symposium on

Print_ISBN

0-7803-8408-3

Type

conf

DOI

10.1109/ISSSTA.2004.1371670

Filename

1371670