user story: i want my phone to automatically alert me when i pass another phone who has set data (let's call it a "profile") that matches mine (i'd like the oth

user story: i want my phone to automatically alert me when i pass another phone who has set data (let's call it a "profile") that matches mine (i'd like the other phone do go off as well); let's set a physical range 'tween phones of 20 meters (could be programmable). so, yes, i want to know how best to transport the data.