Patent ID: 8565786

Claim:
A method comprising: (1) receiving, at a location server: (i) a first measured signal-to-impairment ratio for a first signal that is received by a wireless terminal, and (ii) a second measured signal-to-impairment ratio for a second signal that is received by the wireless terminal; and (2) estimating, at the location server, a first location of the wireless terminal based on the first measured signal-to-impairment ratio and the second measured signal-to-impairment ratio; wherein the first measured signal-to-impairment ratio and the second measured signal-to-impairment ratio are measured at the wireless terminal; and wherein (2) the estimating the first location of the wireless terminal comprises: (2.1) comparing the first measured signal-to-impairment ratio to: (2.1.i) a first expected signal-to-impairment ratio for the first signal when the wireless terminal is at a second location, and (2.1.ii) a second expected signal-to-impairment ratio for the first signal when the wireless terminal is at a third location; and (2.2) comparing the second measured signal-to-impairment ratio to: (2.2.i) a first expected signal-to-impairment ratio for the second signal when the wireless terminal is at the second location, and (2.2.ii) a second expected signal-to-impairment ratio for the second signal when the wireless terminal is at the third location.