Patent ID: 6880103

Claim:
A communication terminal, comprising: an IF/RF unit that changes a radio frequency signal of received data into a received baseband signal and that changes a baseband signal of transmit data to a radio frequency signal for transmission within a packet; a receive unit detects a data signal from the received baseband signal outputted by the IF/RF unit; a data matching unit that receives the data signal from the receive unit and matches data communicated between the communication terminal and an outer processing device; a controlling channel supervising unit that controls a transmission electric power of the communication terminal, by detecting a controlling signal within the received baseband signal, and supervises a channel occupying status; a starting point controlling unit that decides a transmission point of the transmit data and generates a corresponding transmission controlling signal; and a sending unit that outputs the transmit data, which is received from the data matching unit, to the IF/RF unit based on the corresponding transmission controlling signal, wherein the communication terminal does not transmit a separate access preamble for accessing a base station in addition to a preamble contained within a data packet.