  Available throughput performance studies for mobile ad hoc networks (MANETs)
suffer from two major limitations: they mainly focus on the scaling law study
of throughput, while the exact throughput of such networks remains largely
unknown; they usually consider the infinite buffer scenarios, which are not
applicable to the practical networks with limited buffer. As a step to address
these limitations, this paper develops a general framework for the exact
throughput capacity study of a class of buffer-limited MANETs with the two-hop
relay. We first provide analysis to reveal how the throughput capacity of such
a MANET is determined by its relay-buffer blocking probability (RBP). Based on
the Embedded Markov Chain Theory and Queuing Theory, a novel theoretical
framework is then developed to enable the RBP and closed-form expression for
exact throughput capacity to be derived. We further conduct case studies under
two typical transmission scheduling schemes to illustrate the applicability of
our framework and to explore the corresponding capacity optimization as well as
capacity scaling law. Finally, extensive simulation and numerical results are
provided to validate the efficiency of our framework and to show the impacts
brought by the buffer constraint.
