A method, a base station, a User Equipment (UE) and a system for sending and receiving Physical Downlink Control Channel (PDCCH) signaling are disclosed. A method includes determining locations of a first search space and a second search space of a User Equipment (UE). A method also includes sending PDCCH signaling with no Carrier Indication Field (CIF) to the UE in a physically overlapped region between the first search space and the second search space if the physically overlapped region exists and a length of the PDCCH signaling with no CIF in the first search space is equal to a length of PDCCH signaling with the CIF in the second search space.