Delay Optimal Cross-Layer Scheduling Over Markov Channels with Power Constraint

TL;DR

This paper develops an optimal cross-layer scheduling strategy for power-constrained transmitters over Markov channels, minimizing average delay while balancing power use, using a CMDP framework and revealing a queue-length threshold policy.

Contribution

It introduces a delay-optimal scheduling policy with a queue-length threshold structure for Markov channels under power constraints, solved via linear programming.

Findings

The optimal policy has a queue-length threshold structure.

The strategy effectively balances delay and power consumption.

Numerical results confirm the policy's performance and delay-power tradeoff.

Abstract

We consider a scenario where a power constrained transmitter delivers randomly arriving packets to the destination over Markov time-varying channel and adapts different transmission power to each channel state in order to guarantee successful transmission. To minimize the expected average transmission delay of each packet, we formulate the problem into a constrained Markov decision process (CMDP). We reveal the queue-length threshold structure of the optimal policy, i.e., the transmitter sends packets if and only if the queue length surpasses a threshold and obtain the optimal cross-layer scheduling strategy through linear programming (LP). Numerical results validate the performance of the proposed strategy and illustrate a delay-power tradeoff in such scenario.