Spatial interference mitigation for multiple input multiple output ad hoc networks: MISO gains

We consider spatial interference mitigation at the transmitter for multiple input single output ad hoc networks. We apply zero forcing beamforming at the transmitter, and analyze the corresponding network throughput and transmission capacity. Assuming a network with Poisson distributed transmitting nodes and spatially independent Rayleigh fading channels, we apply mathematical tools from stochastic geometry to derive a lower bound on the probability of outage. We derive scaling laws for the transmission capacity and show that for a large number of antennas, the maximum density of concurrently transmitting nodes scales linearly with the number of antennas at the transmitter, for a given outage constraint. Numerical results show that the network throughput achieved by interference nulling at the transmitter is comparable to that achieved by interference cancellation at the receiver.