Some Optimization Trade-offs inWireless Network Coding

摘要

In this paper, we consider different optimizationrntrade-offs in wireless networks with saturated or possibly emptyingrnpacket queues and specify the resulting cross-layer interactionsrnin medium access control (MAC) and network layers. Wernseparately consider scheduled and random access for MAC layer,rnwhereas network layer operations are modeled by network codingrnor plain routing. Our objective is to analyze the trade-offs amongrnperformance objectives of maximizing aggregate or minimumrnthroughput over different source-destination pairs and minimizingrn(transmission and coding) energy costs using a tandemrnwireless network model with the assumptions of omnidirectionalrntransmissions (and node costs), interference effects and singlerntransceiver per node. We do not limit the throughput measures torna common minimum value for all source-destination pairs (suchrnas the Max-flow Min-cut value) but specify the entire achievablernthroughput region that provides the optimization constraintsrnfor the general case of multiple sources. We also extend thernnetwork optimization problem to the case of possibly emptyingrnqueues by specifying the stability region as the constraint set.rnWe consider different multicast communication problems (suchrnas broadcasting and unicasting) and discuss the trade-offs withrnanycast communication (with arbitrary throughput rates).