1. A terminal device, comprising:a receiver;
a transmitter; and
wherein the receiver is configured to receive, from a network device, a first indication information indicating an initial power value of an uplink reference signal to be sent to the network device;
wherein the transmitter is configured to send, in a first uplink subframe on a first carrier in an uplink, the uplink reference signal to the network device based on the initial power value, wherein the first carrier is a carrier on which the terminal device sends neither uplink data nor uplink control information in the uplink;
wherein the processor is configured to determine a first power headroom (PHR) based on the initial power value of the uplink reference signal in the first uplink subframe on the first carrier in the uplink, wherein the first PHR is a PHR of a transmit power of the terminal device in the first uplink subframe or a PHR of a transmit power of the terminal device in the first uplink subframe on the first carrier, wherein the first PHR is further determined based on a plurality of additional factors, including a sound reference signal (SRS) trigger type, a SRS bandwidth, an initial target power of the SRS, and a path loss.