A method includes: an RRU selection decision cycle of a current RRU shared cell arriving; and determining, according to a current downlink measurement item of a user terminal and an uplink measurement item of each RRU, that at least one RRU among the RRUs transmits a downlink carrier signal; or, determining, according to the current downlink measurement item of the user terminal, the uplink measurement item of each RRU, and power specification of each RRU, that at least one RRU among the RRUs transmits a downlink carrier signal, where a downlink channel includes: a traffic channel and a stand-alone dedicated control channel.