Routing over Parallel Queues with Time Varying Channels with Application to Satellite and Wireless Networks

We consider the problem of routing packets from an arbitrary input stream X(t) over a collection of heterogeneous queues in parallel. When the processing rates (μ1,..., μn) of the queues are constant, a simple work conserving routing strategy πWC is shown to hold total system backlog within a fixed upper bound from the resulting backlog of any other policy. Similar results apply to systems with time varying processing rates (μ1(t),..., μn(t)) when routing decisions can be postponed by placing packets in a pre-queue. For the case when routing decisions must be made immediately upon arrival, we demonstrate that the nonpredictive policy of routing packets to the shortest queue ensures system stability (and maintains low packet loss rates for finite buffer systems) whenever the system is stabilizable. Finally, we consider a joint problem of routing and power allocation where, for each time varying channel state ci(t), the rate of each queue i can be varied by adjusting a power parameter pi (subject to power constraints) according to a rate-power curve μi(ci, pi). A throughput maximizing algorithm is developed for this joint problem.