METHOD OF ACCESSING A MOBILE RADIO LAND SYSTEM FROM ONE OF A NUMBER OF MOBILE SYSTEMS

摘要

In a cellular mobile radiotelephone system, two different digital burst access methods are defined using to the greatest extent possible previously defined burst structures. The type of access method to be used in a particular cell is indicated on that cell's control channel. In very large cells, a twoburst access method is used including a shortened pre-access burst and a regular access burst. The shortened pre-access burst avoids collision with other bursts and provides time-alignment information to the cell's base station. In response to a timealignment order, the mobile station then transmits a regular access burst. In smaller cells, a regular single-burst access procedure is used. The access methods use existing burst structures except that the fields CDVCC and SACCH are used for different purposes that may include improved synchronization, control channel identification and reservation of time slots for multi-burst access. Beyond a simple two-burst access method, according to a multi-burst access method, accesses may include essentially an arbitrary number of bursts limited only by system time-out limits.