Trading Rate for Balanced Queue Lengths for Network Delay Minimization

—We consider a communication channel with two transmitters and one receiver, with an underlying rate region which is approximated as a general pentagon. Different from the Gaussian multiple access channel (MAC) capacity region, the sum-rate on the dominant face of this pentagon is not a constant. We allocate rates from this rate region to users according to their current queue lengths in order to minimize the average delay in the system. We formulate the problem as a Markov decision problem (MDP), and derive the structural properties of the corresponding discounted-cost MDP. We show that the delayoptimal policy has a switch curve structure. For the discountedcost problem, we prove that the switch curve has a limit along one of the dimensions. The delay-optimal policy divides the entire queue state space into two via a switch curve. If the queue state is on one side of the switch curve, the system operates at one of the corner points of the rate pentagon which favors maximum sum-rate....

• Type: Journal
• Year: 2011
• Where: JSAC
• Authors: Jing Yang, Sennur Ulukus
• Keywords: JSAC 2011, Markov Decision Problem, Queue Lengths, State Switches