Date Added: Dec 2012
This paper studies the optimal power allocation for outage minimization in point-to-point fading channels with the energy-harvesting constraints and Channel Distribution Information (CDI) at the transmitter. Both the cases with non-causal and causal Energy State Information (ESI) are considered, which correspond to the energy harvesting rates being known and unknown prior to the transmissions, respectively. For the non-causal ESI case, the average outage probability minimization problem over a finite horizon is shown to be non-convex for a large class of practical fading channels. However, the globally optimal "Offline" power allocation is obtained by a forward search algorithm with at most N one-dimensional searches, and the optimal power profile is shown to be non-decreasing over time and have an interesting "Save-then-transmit" structure.