By Topic

Combined coding and spreading in downlink CDMA systems

Sign In

Cookies must be enabled to login.After enabling cookies , please use refresh or reload or ctrl+f5 on the browser for the login options.

Formats Non-Member Member
$33 $13
Learn how you can qualify for the best price for this item!
Become an IEEE Member or Subscribe to
IEEE Xplore for exclusive pricing!
close button

puzzle piece

IEEE membership options for an individual and IEEE Xplore subscriptions for an organization offer the most affordable access to essential journal articles, conference papers, standards, eBooks, and eLearning courses.

Learn more about:

IEEE membership

IEEE Xplore subscriptions

5 Author(s)
Lassing, J. ; Dept. of Signals & Syst., Chalmers Univ. of Technol., Goteborg, Sweden ; Persson, A. ; Ottosson, T. ; Ström, E.
more authors

Changing from orthogonal spreading codes in a direct-sequence CDMA (DS-CDMA) system to more powerful forward error correcting convolutional codes is proven superior in an asynchronous uplink system. This approach is referred to as code-spread CDMA (CS-CDMA). In this paper these two systems are compared in a synchronous downlink scenario. Both systems are assumed to operate over channels with nonzero delay spread, making it difficult to maintain orthogonality between users at the receiver. Using synchronous transmission, the DS-CDMA system is found to outperform the CS-CDMA system at high loads on all simulated channels. However, it is found that if the CS-CDMA system is allowed to transmit different users asynchronously through independent fading channels, like in an uplink scenario, it outperforms the synchronous downlink DS-CDMA system already on channels with modest delay spread

Published in:

Vehicular Technology Conference Proceedings, 2000. VTC 2000-Spring Tokyo. 2000 IEEE 51st  (Volume:3 )

Date of Conference: