| 摘要 |
A selective call system including a system controller, a base station transceiver and a plurality of secondary stations with receivers and low powered transmitters capable of sending spread spectrum signals. Invitations are issued to the secondary stations by the system controller at varying power levels. Only those secondary stations receiving the invitation signal are able to respond. Those secondary stations too far away cannot respond to a low power invitation, and since each secondary station can only respond once, upon a received invitation of increased power, such outer lying secondary stations can respond without interference from closer lying secondary stations. |
