  The problem of determining asymptotic bounds on the capacity of a random ad
hoc network is considered. Previous approaches assumed a threshold-based link
layer model in which a packet transmission is successful if the SINR at the
receiver is greater than a fixed threshold. In reality, the mapping from SINR
to packet success probability is continuous. Hence, over each hop, for every
finite SINR, there is a non-zero probability of packet loss. With this more
realistic link model, it is shown that for a broad class of routing and
scheduling schemes, a fixed fraction of hops on each route have a fixed
non-zero packet loss probability. In a large network, a packet travels an
asymptotically large number of hops from source to destination. Consequently,
it is shown that the cumulative effect of per-hop packet loss results in a
per-node throughput of only O(1/n) (instead of Theta(1/sqrt{n log{n}})) as
shown previously for the threshold-based link model).
  A scheduling scheme is then proposed to counter this effect. The proposed
scheme improves the link SINR by using conservative spatial reuse, and improves
the per-node throughput to O(1/(K_n sqrt{n log{n}})), where each cell gets a
transmission opportunity at least once every K_n slots, and K_n tends to
infinity as n tends to infinity.
