A multi-carrier aggregation method comprising: • determining, by a network side device, according to information about a transmission resource that is obtained when at least one component carrier is successfully obtained through contention, a start time of a scheduling phase (step 401); characterized by • determining, by the network side device, a duration of the scheduling phase, wherein the determining, by the network side device, the duration of the scheduling phase comprises: ∘ determining, by the network side device, the duration of the scheduling phase according to a service volume of a service that is to be transmitted within the scheduling phase, or, ∘ determining, by the network side device, the duration of the scheduling phase according to a quality of service, QoS, of the service that is to be transmitted within the scheduling phase, or, ∘ determining, by the network side device, the duration of the scheduling phase according to the service volume and the QoS of the service that is to be transmitted within the scheduling phase; • determining, by the network side device, an end time of the scheduling phase according to the start time and the duration of the scheduling phase, wherein the scheduling phase is divided by an uplink-downlink switch point into an uplink phase of the scheduling phase and a downlink phase of the scheduling phase, the uplink-downlink switch point is used to divide a time to obtain an uplink time of the component carrier and a downlink time of the component carrier, and uplink-downlink switch points of two or more component carriers are aligned in time; and • performing, by the network side device, downlink transmission with a user equipment in the downlink phase of the scheduling phase, and performing, by the network side device, uplink transmission with the user equipment in the uplink phase of the scheduling phase (step 402). • determining, by a network side device, according to information about a transmission resource that is obtained when at least one component carrier is successfully obtained through contention, a start time of a scheduling phase (step 401); characterized by • determining, by the network side device, a duration of the scheduling phase, wherein the determining, by the network side device, the duration of the scheduling phase comprises: ∘ determining, by the network side device, the duration of the scheduling phase according to a service volume of a service that is to be transmitted within the scheduling phase, or, ∘ determining, by the network side device, the duration of the scheduling phase according to a quality of service, QoS, of the service that is to be transmitted within the scheduling phase, or, ∘ determining, by the network side device, the duration of the scheduling phase according to the service volume and the QoS of the service that is to be transmitted within the scheduling phase; ∘ determining, by the network side device, the duration of the scheduling phase according to a service volume of a service that is to be transmitted within the scheduling phase, or, ∘ determining, by the network side device, the duration of the scheduling phase according to a quality of service, QoS, of the service that is to be transmitted within the scheduling phase, or, ∘ determining, by the network side device, the duration of the scheduling phase according to the service volume and the QoS of the service that is to be transmitted within the scheduling phase; • determining, by the network side device, an end time of the scheduling phase according to the start time and the duration of the scheduling phase, wherein the scheduling phase is divided by an uplink-downlink switch point into an uplink phase of the scheduling phase and a downlink phase of the scheduling phase, the uplink-downlink switch point is used to divide a time to obtain an uplink time of the component carrier and a downlink time of the component carrier, and uplink-downlink switch points of two or more component carriers are aligned in time; and • performing, by the network side device, downlink transmission with a user equipment in the downlink phase of the scheduling phase, and performing, by the network side device, uplink transmission with the user equipment in the uplink phase of the scheduling phase (step 402).