Delay-optimal scheduling for cooperative networks

We consider delay-optimal link selection for a two-hop three-node cooperative network with bursty packet arrivals, where both the source node and the half-duplex cooperative node have exogenous arrivals. We consider the problem of minimizing the random sum queue length process subject to link selection constraints under a general bursty bit flow model and obtain a simple closed-form delay-optimal link selection policy, requiring only 1 bit of state information for each queue. Furthermore, using the structure of the delay-optimal link selection policy, we obtain the closed-form average bit delay performance for deterministic and Poisson packet arrival processes, Finally, we derive a new lower bound for the delay penalty incurred by the (throughput-optimal) dynamic backpressure (DBP) link selection algorithm, as compared with the delay-optimal link selection policy.