Provided are an information sending method and apparatus, an information receiving method and apparatus, a base station, a terminal, and a communication system. The base station sends uplink transmission configuration information to the terminal. The uplink transmission configuration information includes configuration information of an uplink channel resource and/or configuration information of a downlink control channel search space. Information carried in a downlink control channel of the downlink control channel search space includes downlink control information (DCI). In this manner, the terminal can detect the DCI sent by the base station and a downlink transmission between the base station and the terminal is implemented. Therefore, through the indication of the uplink transmission configuration information, information transmission can be smoothly implemented no matter whether the terminal is in an RRC-CONNECT state or an RRC-IDLE state. Naturally, when the terminal is in the RRC-IDLE state, data transmission can be completed without state switching, thus reducing power consumption and resource consumption caused by state switching of the terminal, being beneficial to achieving optimal configuration of terminal resources, and enhancing user experience at the terminal side.