  Despite lots of literature has been dedicated to researching the delay
performance in two-hop relay (2HR) mobile ad hoc networks (MANETs), however,
they usually assume the buffer size of each node is infinite, so these studies
are not applicable to and thus may not reflect the real delay performance of a
practical MANET with limited buffer. To address this issue, in this paper we
explore the packet end-to-end delay in a 2HR MANET, where each node is equipped
with a bounded and shared relay-buffer for storing and forwarding packets of
all other flows. The transmission range of each node can be adjusted and a
group-based scheduling scheme is adopted to avoid interference between
simultaneous transmissions, meanwhile a handshake mechanism is added to the 2HR
routing algorithm to avoid packet loss. With the help of Markov Chain Theory
and Queuing Theory, we develop a new framework to fully characterize the packet
delivery processes, and obtain the relay-buffer blocking probability (RBP)
under any given exogenous packet input rate. Based on the RBP, we can compute
the packet queuing delay in its source node and delivery delay respectively,
and further derive the end-to-end delay in such a MANET with limited buffer.
