Terminal supporting peer-to-peer communication, and communication and billing methods based on the same

A terminal supporting peer-to-peer (P2P) communication, comprising:

• a transmission module for modulating and spreading transmission data, and outputting the transmission data as a transmission signal;
• a reception module for receiving a downlink signal from a base station or a P2P signal from an adjacent terminal, de-spreading and demodulating the received signal, and outputting it as received data;
• a receive channel measurer for measuring intensity of the received signal using an averaging process;
• and
• a communication mode controller for controlling handover between the base station communication mode and a P2P communication mode according to the intensity of the received signal measured by the receiving channel measurer,
• wherein the terminal automatically performs the handover to the P2P communication mode according to the intensity of the received signal measured by the receiving channel measurer without the base station having knowledge of the terminal performing P2P communication when the terminal is in the P2P communication mode,
• wherein the communication mode controller controls the terminal to perform P2P communication with the adjacent terminal when the intensity of the received signal measured by the receiving channel measurer exceeds a threshold value, and to communicate with the adjacent terminal via the base station in the base station communication mode when the intensity of the received signal measured by the receiving channel measurer is less than the threshold value.