The optimal power allocation was investigated when both channel and queue state information was taken into account.By modeling the system from a cross-layer perspective

an optimization problem was formulated on power allo-cation where the maximal power requirement of a user was determined by the number of its backlog packets.The ana-lytical solution as well as its algorithm

which refer to as water filling in cellar（WFIC）

were proposed.The proposed WFIC can be reduced to traditional water-filling（TWF） method as a special case where queue state was ignored.Simula-tion results show that the proposed method can achieve lower queuing delay compared to conventional methods.