Random access request over a common CDMA channel using a preamble with a selected signature

摘要

The invention relates to packet and random access in which multiple terminals (eg mobile phones) transmit data via a common code division multiple access (CDMA) Channel Terminals select one of available preamble signatures and one of available access slots and transmit a preamble (Fig.5). A base station tries to acquire the preamble and then broadcasts to all terminals whether the preambles are acquired or not (Fig.6). The terminals then transmit a data or retransmit a preamble according to the result of the preamble acquirement (Fig.5). The apparatus and method have improved network efficiency by reducing unnecessary data transmission and interference signal. An improved characteristic of time delay by ramping to adequate power level more quickly by re-transmitting preamble-by-preamble.