06404775 is referenced by 279 patents.
A repeater allows terminals of a first communications system, employing a first air protocol or radio interface, to communicate with terminals of a second communications system, employing a second air protocol or radio interface different from the first. Where the first and second air protocols differ only in operating frequency, but are otherwise compatible, the repeater may linearly translate signals from the first operating frequency to the second operating frequency, and vice versa, without demodulating and remodulating the signals. Where the air protocols differ in other ways, the repeater receives and demodulates signals from the first system, converts the signals to a common format, and remodulates and retransmits the signals according to the second air protocol (and vice versa), in the same frequency bands or in different frequency bands. The repeater translates control and signalling information transmitted in compliance with one air protocol to a format which complies with the other air protocol and has the same or equivalent effect. For each of the two communications system, the repeater emulates the functions of a terminal in that communications system, so that corresponding terminals in that system may communicate transparently with the repeater. The repeater provides a connection between the two emulated terminals, thereby allowing a terminal of the first system to use the repeater to communicate with an otherwise incompatible terminal of the second system.