Scheduled System Maintenance:
On Monday, April 27th, IEEE Xplore will undergo scheduled maintenance from 1:00 PM - 3:00 PM ET (17:00 - 19:00 UTC). No interruption in service is anticipated.
By Topic

Adaptive QAM modulations with complex spreading for high-speed mobile multimedia communications

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
$31 $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

2 Author(s)
Yeonho Chung ; Dept. of Inf. & Commun., Dongeui Univ., Pusan, South Korea ; Kihong Song

This paper considers an adaptive QAM modem with complex spreading and noncoherent detection combined. The adaptation is performed by varying the modulation level of QAM, depending upon received signal strength which reflects instantaneous channel conditions. The adaptation mechanism allows a 2- or 3-bit increase at a time, if the channel condition is considered to be good. Simulation results show that, for a flat fading channel, the effect of spreading was minimal and the average number of bits per symbol (ABPS) for each symbol block transmitted is higher than 5.0 with a symbol rate of 32 kbaud. In case of a frequency selective fading channel, two approaches, complex spreading and an oversampling technique, were compared. It was found that the oversampling technique outperforms complex spreading. ABPS for frequency selective fading channels is approximately 5.5 with a SNR value of 40 dB

Published in:

Vehicular Technology Conference, 2000. IEEE-VTS Fall VTC 2000. 52nd  (Volume:1 )

Date of Conference: