摘要 |
<p>A cell extender (100) for use in digital cellular telephone systems (102) comprises a control module (134), a scanning module (132), and several traffic modules (130's). The control module (134) bidirectionally repeats the donor cell site (110) control channels. Voice modules therein bidirectionally repeat selected donor traffic channels for mobiles (112). The voice module amplifies and translates the Reverse Digital Traffic Channel (RDTC) (164) (transmitted by the mobile (112)). The voice module reframes the Forward Digital Traffic Channel (166), and advances its timing such that RDTC signals transmitted by the mobile (112) and repeated by the cell extender (100) arrive at the donor (110) with the correct timing alignment. The timing advance compensates for RF path propagation delay between the donor (110) and the cell extender (100), and for any additional delay through the cell extender (100). If the voice module determines that the mobile (112) is leaving the cell extender coverage area, it sends a hand-off message returning the mobile (112) to the assigned donor traffic channel.</p> |