  Radio dynamic zones (RDZs) are geographically bounded areas where novel
advanced wireless technologies can be developed, tested, and improved, without
the concern of interfering to other incumbent radio technologies nearby the
RDZ. In order to operate an RDZ, use of a real-time spectrum monitoring system
carries critical importance. Such a monitoring system should detect out-of-zone
(OoZ) signal leakage outside of the RDZ, and if the interference to nearby
receivers is intolerable, the monitoring system should be capable of mitigating
such interference. This can e.g. be achieved by stopping operations inside the
RDZ or switching to other bands for RDZ operation. In this paper, we introduce
a spectrum monitoring concept for OoZ signal leakage detection at RDZs, where
sensor nodes (SNs) are installed at the boundary of an RDZ and monitor the
power leakage from multiple transmitters within the RDZ. We propose a
prediction algorithm that estimates the received interference at OoZ
geographical locations outside of the RDZ, using the measurements obtained at
sparsely located SNs at the RDZ boundary. Using computer simulations, we
evaluate the performance of the proposed algorithm and study its sensitivity to
SN deployment density.
