초록 ▼

Seamless hand-off of air-to-ground telephony calls is achieved autonomously within an aircraft by using one of at least two radio links to search for additional ground stations. The search for candidate ground stations for hand-off is expedited by eliminating ground stations exhibiting zero or negat

Seamless hand-off of air-to-ground telephony calls is achieved autonomously within an aircraft by using one of at least two radio links to search for additional ground stations. The search for candidate ground stations for hand-off is expedited by eliminating ground stations exhibiting zero or negative Doppler effects. Other values indicating quality of the link corresponding to the channel over which the search is conducted is compared with the quality of the call and an alternate call is established using the call identification code previously established for the call in progress. The hand-off of the call may then be easily conducted by transferring the voice signal to the channel over which the search was conducted. This is preferably done at a time when the transmission quality of the two channels would be approximately the same or the quality improved on the channel to which hand-off is made.

대표청구항 ▼

1. A method for providing communication between a mobile terminal and a plurality of unsynchronized base stations comprising the steps of:initiating the establishment of a first two-way call over a first communication link, said first two-way call carrying two-way signals between said mobile termina

1. A method for providing communication between a mobile terminal and a plurality of unsynchronized base stations comprising the steps of:initiating the establishment of a first two-way call over a first communication link, said first two-way call carrying two-way signals between said mobile terminal and a first base station; establishing a second communication link between said mobile terminal and a second base station; evaluating at least one characteristic of said second communication link at said mobile terminal; in response to said evaluating step, said mobile terminal initiating the establishment of a second two-way call, which is a duplicate of said first two-way call, over said second communication link while said first two-way call exists; and performing a hand-off by simultaneously switching said two-way signals from said first communication link to said second communication link under control of said mobile terminal.