  In this paper, we study the problem of power allocation for streaming
multiple variable-bit-rate (VBR) videos in the downlink of a cellular network.
We consider a deterministic model for VBR video traffic and finite playout
buffer at the mobile users. The objective is to derive the optimal downlink
power allocation for the VBR video sessions, such that the video data can be
delivered in a timely fashion without causing playout buffer overflow and
underflow. The formulated problem is a nonlinear nonconvex optimization
problem. We analyze the convexity conditions for the formulated problem and
propose a two-step greedy approach to solve the problem. We also develop a
distributed algorithm based on the dual decomposition technique. The
performance of the proposed algorithms are validated with simulations using VBR
video traces under realistic scenarios.
