In LTE, there is only uplink power control, and power allocation is used in the downlink. The power control between cells is realized through ICIC technology. The open-loop power control in the cell includes PRACH channel and Msg3 in PUSCH. The loop means that the UE directly sends information, which does not require feedback from the eNB. The closed-loop power control includes the PUSCH channel, the PUCCH channel, and the SRS signal. The closed-loop means that the UE sends information. Feedback from the eNB is required, telling the UE how much power is needed to send information next time.