  This paper develops a distributed algorithm for rate allocation in wireless
networks that achieves the same throughput region as optimal centralized
algorithms. This cross-layer algorithm jointly performs medium access control
(MAC) and physical-layer rate adaptation. The paper establishes that this
algorithm is throughput-optimal for general rate regions. In contrast to on-off
scheduling, rate allocation enables optimal utilization of physical-layer
schemes by scheduling multiple rate levels. The algorithm is based on local
queue-length information, and thus the algorithm is of significant practical
value. The algorithm requires that each link can determine the global
feasibility of increasing its current data-rate. In many classes of networks,
any one link's data-rate primarily impacts its neighbors and this impact decays
with distance. Hence, local exchanges can provide the information needed to
determine feasibility. Along these lines, the paper discusses the potential use
of existing physical-layer control messages to determine feasibility. This can
be considered as a technique analogous to carrier sensing in CSMA (Carrier
Sense Multiple Access) networks. An important application of this algorithm is
in multiple-band multiple-radio throughput-optimal distributed scheduling for
white-space networks.
