  This paper studies how to achieve the maximal link throughputs in a CSMA
wireless network through offered-load control. First, we propose an analytical
model, contention-graph-combination (CGC), to describe the relationship between
the offered-load and the output link throughputs of an unsaturated CSMA
network. Based on CGC, we then formulate a linear optimization model to improve
the aggregate link throughput through properly setting the occurrence
probabilities of each sub-network, based on which we can obtain the optimal
offered-load of each link. Simulation results bore out the accuracy of our CGC
analysis and the maximal link throughputs can be closely achieved. Different
from prior work in which CSMA protocol parameters are adaptively adjusted to
achieve better performance, in this paper we propose to achieve maximal link
throughputs by adjusting the rates of the traffic pumped into the source nodes
of links, which runs in a software manner and is more practical to implement in
real networks.
