  Interference between nodes directly limits the capacity of mobile ad hoc
networks. This paper focuses on spatial interference cancelation with perfect
channel state information (CSI), and analyzes the corresponding network
capacity. Specifically, by using multiple antennas, zero-forcing beamforming is
applied at each receiver for canceling the strongest interferers. Given spatial
interference cancelation, the network transmission capacity is analyzed in this
paper, which is defined as the maximum transmitting node density under
constraints on outage and the signal-to-interference-noise ratio. Assuming the
Poisson distribution for the locations of network nodes and spatially i.i.d.
Rayleigh fading channels, mathematical tools from stochastic geometry are
applied for deriving scaling laws for transmission capacity. Specifically, for
small target outage probability, transmission capacity is proved to increase
following a power law, where the exponent is the inverse of the size of antenna
array or larger depending on the pass loss exponent. As shown by simulations,
spatial interference cancelation increases transmission capacity by an order of
magnitude or more even if only one extra antenna is added to each node.
