A packet-based, hierarchical communication system, arranged in a spanning tree configuration, is described in which wired and wireless communication networks exhibiting substantially different characteristics are employed in an overall scheme to link portable or mobile computing devices. The network...http://www.google.de/patents/US8139749?utm_source=gb-gplus-sharePatent US8139749 - Hierarchical data collection network supporting packetized voice communications among wireless terminals and telephones
