Title :
Reduction of Feedback Overload by Exploiting Adaptive Channel in OFDMA systems
Author :
Iijima, Satoru ; Zhou, Rui ; Sasase, Iwao
Author_Institution :
Keio Univ., Yokohama
Abstract :
In channel adaptive OFDM A systems, it is important to feed back channel information in a fast, accurate and efficient way to improve the system performance. However, base station requires a large amount of feedback information of channel state information (CSI) in the adaptive channel. In order to reduce the overload of CSI feedback, we propose a feedback scheme which only selects the users scheduled in the next time slot to feed back the channel information according to user mobility. We use adaptive modulation to apply bit rate adaptation depending on user channel condition, where the scheduling time is fixed. By fixing the packet size, scheduling time and feedback period can be fit to different time slots according to user transmission rate. We demonstrate by computer simulation that the proposed scheme can reduce the overload of user feedback with the minimum suppression of the throughput degradation.
Keywords :
OFDM modulation; adaptive modulation; channel allocation; frequency division multiple access; adaptive channel OFDMA system; adaptive modulation; channel state information; feedback overload reduction; orthogonal frequency division multiple access; user mobility; Adaptive systems; Base stations; Bit rate; Channel state information; Computer simulation; Feeds; OFDM; Processor scheduling; State feedback; System performance;
Conference_Titel :
Communications, Computers and Signal Processing, 2007. PacRim 2007. IEEE Pacific Rim Conference on
Conference_Location :
Victoria, BC
Print_ISBN :
978-1-4244-1189-4
Electronic_ISBN :
1-4244-1190-4
DOI :
10.1109/PACRIM.2007.4313200