Abstract: The present invention discloses a method for determining a paging slot by a base station for CDMA trunking service, wherein the method includes: the base station determine a slot cycle index according to PTT version number of a mobile station, and determine a slot cycle used for the mobile station according to the slot cycle index. The present invention can solve the problem of slow access when the mobile station is called after power-on, which exists in the related art, thus can improve the speed of power-on access, and can determine the paging slot for a base station and a terminal which can not support a minus slot paging.

Abstract: The present invention discloses a method of encoding group identification in a CDMA trunking system. This method comprises: a trunking group where mobile stations locate is encoded by a preset GID encoding method to generate a GID of the trunking group. The GID is a character string consisting of a plurality of decimal digits from 0 to 9 for external processing, and is processed into a binary character string according to a GID type for internal processing.

Abstract: The present invention provides a method of terminal PTT registration based on CDMA trunking system and the system thereof, comprising: a user terminal is powered and a normal CDMA registration flow is completed, and afterwards the value of a PTT registration message counter is initialized; the user terminal sends a PTT registration message to a dispatching sub-system (server) and starts a PTT registration timer; and a corresponding process is performed according to the response message from the dispatching server, which is the reception of the trunking registration or the rejection of the trunking registration. Therefore the terminal with CDMA trunking function can avoid the problem caused by a failed PTT registration.