Title: Adaptive Modulation for Coded Cooperative Systems
Authors: Zinan Lin, Elza Erkip, Monisha Ghosh (Poster I, 12)

ABSTRACT

Throughput is an important performance measure for data communications over wireless links. In this work, we consider adaptive modulation for cooperative relaying to maximize the data throughput. We compute the throughput and compare the performance of four different schemes with adaptive modulation: Direct transmission, multihop, stationary and dynamic coded cooperation. We find that multihop transmission with adaptive modulation increases the data throughput compared to direct transmission only in low to medium SNR range. Adaptive modulation for coded cooperation provides much higher throughput than multihop and direct transmission, with dynamic coded cooperation outperforming the stationary one. We also find that to maximize the data throughput in direct transmission and multihop the modulation mode for each hop only depends on the channel quality from the transmitter to the receiver. However, in coded cooperation a system wide optimization is necessary. Ongoing work investigates adapting the code rate and level of cooperation as well as modulation, and an information theoretic approach to provide bounds on the throughput performance.