  We study the optimal transmission scheme that maximizes the local capacity in
two-dimensional (2D) wireless networks. Local capacity is defined as the
average information rate received by a node randomly located in the network.
Using analysis based on analytical and numerical methods, we show that maximum
local capacity can be obtained if simultaneous emitters are positioned in a
grid pattern based on equilateral triangles. We also compare this maximum local
capacity with the local capacity of slotted ALOHA scheme and our results show
that slotted ALOHA can achieve at least half of the maximum local capacity in
wireless networks.
