  The cost-effective impact and fundamental limits of infrastructure support
with rate-limited wired backhaul links (i.e., GreenInfra support), directly
connecting base stations (BSs), are analyzed in a large-scale hybrid network of
unit node density, where multi-antenna BSs are deployed. We consider a general
scenario such that the rate of each BS-to-BS link scales at an arbitrary rate
relative to the number of randomly located wireless nodes, $n$. For the
operating regimes with respect to the number of BSs and the number of antennas
at each BS, we first analyze the minimum rate of each backhaul link,
$C_{\textrm{BS}}$, required to guarantee the same throughput scaling as in the
infinite-capacity backhaul link case. We then identify the operating regimes in
which the required rate $C_{\textrm{BS}}$ scales slower than $n^\epsilon$ for
an arbitrarily small $\epsilon>0$ (i.e., the regimes where $C_{\textrm{BS}}$
does not need to be infinitely large). We also show the case where our network
with GreenInfra is fundamentally in the infrastructure-limited regime, in which
the performance is limited by the rate of backhaul links. In addition, we
derive a generalized throughput scaling law including the case where the rate
of each backhaul link scales slower than $C_{\textrm{BS}}$. To validate the
throughput scaling law for finite values of system parameters, numerical
evaluation is also shown via computer simulations.
