Methods and systems for proximity based communication between users of proximity communication devices (“PCDs”). A localized communication network is established by peer-to-peer communication between PCDs. Each PCD communicates with other PCDs in a wireless, localized, peer-to-peer network structure....http://www.google.com.hk/patents/US7643833?utm_source=gb-gplus-share專利 US7643833 - Methods and systems for proximity communication
