Using a derived table of signal strength data to locate and track a user in a wireless network

A computer-readable medium storage device having computer-executable instructions for performing steps, comprising:

• measuring a wireless signal strength;
• comparing the measured wireless signal strength to a table of mathematically estimated wireless signal strengths and corresponding mobile unit locations;
• finding a table entry whose mathematically estimated wireless signal strength is closest, by distance in signal space, to the measured wireless signal strength;
• and, determining the location of the mobile unit with reference to the found table entry, wherein the mathematically estimated signal strengths in the table are determined without measurement of wireless signal strength at the corresponding mobile unit locations.

A computer-readable storage device having stored thereon computer instructions that when executed carry out the acts comprising:

• populating a table comprising a plurality of values representative of locations within a circumscribed area and corresponding signal strength values representative of plurality of signal strengths received from a plurality of base stations wherein said table comprises at least one location derivable by signal strength values that are derived empirically without the need to measure signal strength at the at least one location;
• receiving over at least one local area network a plurality of values representative of measured signal strengths from at least two of said plurality of base stations;
• correlating the plurality of values representative of measured signal strengths from said at least two base stations to said plurality of values representative of base station signal strengths in said table to determine at least one value representative of location within the circumscribed area;
• and
• estimating a location of a wireless device as a function of said at least one value.

A system for locating a wireless device comprising:

• means for populating a data structure comprising a plurality of values representative of locations within a circumscribed area and corresponding signal strength values representative of plurality of signal strengths received from a plurality of base stations wherein at least one signal strength value is derived mathematically without the need for measuring signal strength at the corresponding location;
• means for receiving over a local area network a plurality of values representative of measured signal strengths from at least two of said plurality of base stations;
• means for correlating the plurality of values representative of measured signal strengths from said at least two base stations to said plurality of values representative of base station signal strengths in said data structure to determine at least one value representative of location within the circumscribed area;
• and
• means for estimating a location of a wireless device as a function of said at least one value.

A system for locating a wireless device comprising:

• at least one local area network;
• a plurality of wireless base stations are physically linked together and coupled to said at least one local area network;
• a computer system comprising a processor and memory in communication with said plurality of wireless base stations by way of said at least one local area network;
• a table stored in said memory wherein said table comprises a plurality of locations with corresponding signal strength values wherein at least some of the signal strengths are mathematically derived without the need for measuring wireless signal strengths at the corresponding location,
• computer instructions stored in said memory;
• said computer instructions executable by said processor to receive measured signal strength values from said wireless device and to correlate the measure signal strength values with signal strength values corresponding to at least one location in said table;
• and
• computer instructions stored in said memory;
• said computer instructions executable by said processor to determine a location of said mobile unit on a floor plan as a function of the at least one location in said table.

A system for locating a wireless device comprising:

• means for populating a data structure comprising a plurality of values representative of locations within a circumscribed area and corresponding signal strength values representative of plurality of signal strengths received from a plurality of base stations connected to at least one local area network wherein at least one of the signal strength values is mathematically derived without the need for measuring wireless signal strengths at the mathematically derived locations;
• means for receiving from a wireless device a plurality of values representative of measured signal strengths from at least two of said plurality of base stations;
• means for correlating the plurality of values representative of measured signal strengths from said at least two base stations to said plurality of values representative of base station signal strengths in said data structure to determine at least one value representative of location within the circumscribed area;
• and
• means for estimating a location of a wireless device as a function of said at least one value.