On the low SNR capacity of log-normal turbulence channels with full CSI

Abstract

In this paper, we characterize the low signal-to-noise ratio (SNR) capacity of wireless links undergoing the log-normal turbulence when the channel state information (CSI) is perfectly known at both the transmitter and the receiver. We derive a closed form asymptotic expression of the capacity and we show that it scales essentially as ASNR where A is the water-filling level satisfying the power constraint. An asymptotically closed form expression of A is also provided. Using this framework, we also propose an on-off power control scheme which is capacity achieving in the low SNR regime.