Energy-Delay tradeoff in Multiple Access
Electrical Engineering and Computer Science Department
University of Michigan
Ann Arbor, MI, 48109-2122
In this paper we study the tradeoff between energy and delay in a multiple access channel (MAC).
Messages arrive at the queues of the individual users and users decide whether to service them. Trans-
mission of a message consumes energy and is successful only if one user transmits at a time. Users do
not communicate but can observe a broadcasted feedback message from the base station indicating the
success or not of the previous transmission. Delays are captured by considering the queue lengths of
We formulate this problem as a decentralized stochastic control problem, the two controllers being
the two users who, in the presence of limited information about each other, decide whether to transmit
at each time slot. The decentralized aspect of this control problem makes it fundamentally different from
the corresponding single-user counterparts and multi-user counterparts assuming a centralized controller.
As a result, the tools from Markov decision processes (MDPs) and partially observed MDPs (POMDPs)