We consider the problem of adaptive modulation and receiver design for DS-CDMA fading channels with imperfect channel state information. The goal is to adapt the geometry of the signal constellation within the subspace spanned by a small number of spreading codes (multicoding) in order to maximize throughput, minimize power consumption, or control bit error rate in the presence of uncertainty regarding instantaneous channel state information. We study two possible cost functions based on J-divergence and investigate their relationship to effective system capacity via bounds on the mutual information between the channel input and output given an estimate of the channel state information. The bounds will be used in future analytical and simulation studies to evaluate the performance improvement associated with the proposed adaptive modulation scheme.

Date Published: 27 July 2001
PDF: 14 pages
Proc. SPIE 4531, Modeling and Design of Wireless Networks, (27 July 2001); doi: 10.1117/12.434454

Published in SPIE Proceedings Vol. 4531:
Modeling and Design of Wireless Networks
Edwin K. P. Chong, Editor(s)