METHOD AND ARRANGEMENT FOR RADIO TELEPHONE CALL TRANSFER IN A SUBWAY COMMUNICATION SYSTEM

摘要

PCT No. PCT/GB96/02590 Sec. 371 Date Jul. 17, 1997 Sec. 102(e) Date Jul. 17, 1997 PCT Filed Oct. 22, 1996 PCT Pub. No. WO97/16892 PCT Pub. Date May 9, 1997Radio telephone apparatus for use in an underground railway system comprises two base stations 3, 4 respectively located at successive railway stations 1, 2. The base station 3 feeds a radiating cable 7 extending in the tunnel bore towards the base station 4 which feeds a radiating cable 12 extending in the tunnel bore towards the base station 3. When a train travels from the station 1 to the station 2, the mobile radio on the train effects call handover, ie transference of communication with cable 7 to communication with cable 12. To ensure no interruption in a call during handover, an attenuator 16 is incorporated in the cable 7 adjacent its end, such that the mobile radio effects call handover to the cable 12 before losing communication with the cable 7, even at the maximum possible speed of the train.