Patent ID: 7685524

Claim:
A wireless communication terminal for communication with a plurality of wireless base stations, the plurality of wireless base stations including a first wireless base station and a second wireless base station, the wireless communication terminal comprising: acquisition means for acquiring; (a) a first electric field strength of a first electric wave received from said first base station; (b) a first unique ID for said first base station; (c) a second electric field strength of a second electric wave received from said second base station; and (d) a second unique ID for said second base station; and location estimation means for estimating a relative distance between a present location and a previous location by: (a) initializing a variable distance to a first value; (b) for: (i) said first electronic filed strength; (ii) said first unique ID; (iii) said second electronic field strength; and (iv) said second unique ID, determining whether a calculation loop is complete; (c) in response to a determination that the said calculation loop is not complete: (i) determine whether said first unique ID is equal to said second unique ID; (ii) in response to a determination that said first ID being equal to said second ID, set said variable distance to a different second value and repeat step (b); and (iii) in response to a determination that said first ID is not equal to said second ID, repeat step (b); and (d) in response to a determination that said calculation loop is complete, set said variable distance to a different third value as said relative distance.