| 摘要 |
A mobile telephone system has in a cell a base station and sub-stations which are connected to a mobile switching center. The mobile telephone system has control channels and frequencies which are time divided to traffic channels. Some of the frequencies are selected as identification frequencies. Each of the sub-stations is assigned a unique set of frequencies from among the identification frequencies and constantly transmit their respective frequency set. A mobile station connected to the base station listens to the identification frequencies and reports the strongest of these frequencies to the mobile switching center. The mobile switching center compares the reported frequencies with the unique set of frequencies, compares the reported signal strength with a threshold value and selects the nearest sub-station for handoff. The mobile switching center switches from the base station to a connection with the sub-section. The mobile station continues to listen to the identification frequencies and reports the signal strength on its connection. When the strength of the signals from the selected sub-station is low, the connection is switched back to the base station. |
