A downlink channel transmitting method performed by a base station, the method comprising indicating explicitly or implicitly, a transmitting period of a group common physical downlink control channel, wherein the indicating explicitly the transmitting period of the group common physical downlink control channel comprises notifying to all terminals within a coverage range of the base station, through a broadcast signaling, the transmitting period of the group common physical downlink control channel; characterised in that: the method further comprises: determining, based on a protocol, a starting time slot position of transmitting the group common physical downlink control channel; or notifying to all the terminals within the coverage range of the base station, through the broadcast signaling, the starting time slot position of transmitting the group common physical downlink control channel; wherein subsequent to the determining, based on the protocol, the starting time slot position of transmitting the group common physical downlink control channel, or notifying to all the terminals within the coverage range of the base station, through the broadcast signaling, the starting time slot position of transmitting the group common physical downlink control channel, the method further comprises: determining a transmitting time slot, based on the transmitting period and the starting time slot position of the group common physical downlink control channel; transmitting the group common physical downlink control channel on the transmitting time slot. indicating explicitly or implicitly, a transmitting period of a group common physical downlink control channel, wherein the indicating explicitly the transmitting period of the group common physical downlink control channel comprises notifying to all terminals within a coverage range of the base station, through a broadcast signaling, the transmitting period of the group common physical downlink control channel; characterised in that: the method further comprises: determining, based on a protocol, a starting time slot position of transmitting the group common physical downlink control channel; or notifying to all the terminals within the coverage range of the base station, through the broadcast signaling, the starting time slot position of transmitting the group common physical downlink control channel; wherein subsequent to the determining, based on the protocol, the starting time slot position of transmitting the group common physical downlink control channel, or notifying to all the terminals within the coverage range of the base station, through the broadcast signaling, the starting time slot position of transmitting the group common physical downlink control channel, the method further comprises: determining a transmitting time slot, based on the transmitting period and the starting time slot position of the group common physical downlink control channel; transmitting the group common physical downlink control channel on the transmitting time slot. determining, based on a protocol, a starting time slot position of transmitting the group common physical downlink control channel; or notifying to all the terminals within the coverage range of the base station, through the broadcast signaling, the starting time slot position of transmitting the group common physical downlink control channel; wherein subsequent to the determining, based on the protocol, the starting time slot position of transmitting the group common physical downlink control channel, or notifying to all the terminals within the coverage range of the base station, through the broadcast signaling, the starting time slot position of transmitting the group common physical downlink control channel, the method further comprises: determining a transmitting time slot, based on the transmitting period and the starting time slot position of the group common physical downlink control channel; transmitting the group common physical downlink control channel on the transmitting time slot. determining a transmitting time slot, based on the transmitting period and the starting time slot position of the group common physical downlink control channel; transmitting the group common physical downlink control channel on the transmitting time slot.