Patent ID: 7630707

Claim:
A method of providing an out of range warning by a wireless device with respect to a wireless network, comprising: receiving a wireless transmission; determining a current quality metric for the received wireless transmission; estimating a period of time until the wireless device is out of range of the wireless network; issuing the out of range warning that includes the estimated period of time; associating a time stamp with the current quality metric; storing the current quality metric and the associated time stamp as a previous quality metric; updating the current quality metric and the time stamp; and calculating a time rate of change of the quality metric; wherein the calculating the time rate of change of the quality metric, comprises: subtracting the updated current quality metric from the previous quality metric to form a delta quality metric; and dividing the delta quality metric by a time interval corresponding to difference between the current time stamp and the previous time stamp; and wherein calculating the estimated period of time until the wireless device is out of range of the wireless network, comprises: determining a difference between the current quality metric and a quality metric corresponding to the effective boundary of the wireless network; and dividing the difference by the time rate of change of the quality metric.