Rate-Optimal Signal Design for Wireless Communications

摘要

In a tactical communications scenario, the transmitter will only have an imperfect estimate of the temporally correlated mobile RF channel. Given imperfect channel state information (CSI), we address the optimal signal design problem. Using the cutoff rate metric, we determine: (a) the optimal allocation of power and bandwidth between information and training signals, (b) the optimal binary input as a function of SNR and CSI quality, (c) and adaptive modulation scheme which switches between only two inputs based on the CSI quality. We show that this simple adaptive modulation scheme is nearly optimal at moderate to high SNR. We also establish that there is at most a 1 dB increase in the maximum penalty for using On-Off Keying instead of BPSK.