Location-based queries (LBQs) have become a hot research topic in the database domain. This paper discusses the issue of processing nearest neighbor (NN) queries in road networks under wireless broadcast environments. For a certain road network together with its data objects, the corresponding Network Voronoi Diagram (NVD) is constructed. And then the D-tree index which is based on the NVD diagram is also constructed. Next, the D-tree index is linearized to support the NN query processing, and the corresponding NN query processing method is pr...