A method and apparatus for a hand-off of a call-in-progress according to the present invention is arranged such that both a first ratio of a length of time, in which a measured value of SNR is below a predetermined "threshold" to a total length of the measuring time, and a second ratio of a length of...http://www.google.de/patents/US5067171?utm_source=gb-gplus-sharePatent US5067171 - Method and apparatus for hand-off of call in progress
