Techniques are presented for identifying mobile devices within a coverage region of a wireless station. Positions for mobile devices, if any, within the coverage region are determined. It is then determined whether the positions are within one or more defined areas, called “notification areas” herein....http://www.google.com/patents/US7136658?utm_source=gb-gplus-sharePatent US7136658 - High-rate proximity detection with the ability to provide notification
