Spatial interference cancelation for mobile Ad hoc networks: Imperfect CSI

Abstract

Spatial interference cancelation based on zeroforcing beamforming significantly improves the throughput of a mobile ad hoc network. Nevertheless, the performance of spatial interference cancelation can be degraded by imperfect channel estimation at receivers. We analyze the impact of inaccurate channel state information (CSI) on network transmission capacity by modeling transmitters as a Poisson point process and applying mathematical tools from stochastic geometry. CSI inaccuracy leads to smaller throughput and larger outage probability of each data link. Such performance loss can be controlled by choosing the length of training sequences as derived. Furthermore, increasing this length logarithmically with the inverse of the decreasing target outage probability achieves the same network-capacity scaling laws as for perfect CSI. Simulation results show that spatial interference cancelation increases transmission capacity by an order of magnitude or more despite CSI inaccuracy. © 2008 IEEE