Localization of non-cooperative OFDM sources with noncoherent snapshots

We investigate the problem of localization of sources transmitting OFDM communication signals. A non-cooperative setting is considered whereby the set of subcarriers used by each source is unknown. We propose an iterative localization algorithm which jointly estimates the location of the sources in both spatial and spectral domains. Furthermore, the subarrays collecting the source signals are not required to be synchronized. This eliminates the need for accurate clock synchronization across the geographically dispersed subarrays. The proposed method is based on the expectation-maximization (EM) algorithm, with a nested likelihood ratio test within each EM iteration in order to detect the subcarrier occupancy of each source. The efficacy of the algorithm is illustrated via simulation results.