Patent ID: 7570948

Claim:
A mobile station comprising: an electric field strength measuring means for, in a link channel establishment sequence in which a control channel is switched to a traffic channel, measuring (i) an electric field strength, in mW, of a burst signal that is sent from a first base station via the traffic channel and (ii) an electric field strength, in mW, of an interference wave of the traffic channel; and a control means for, based on a measurement result obtained by the electric field strength measuring means, controlling an operation of establishing a link for the traffic channel, wherein the mobile station (1) selects a first base station from a plurality of base stations according to electric field strengths of signals transmitted on control channels corresponding to the plurality of base stations, and enters into a standby status, and (2) establishes first a link by transmitting/receiving burst signals for establishing synchronization to/from the first base station via a traffic channel which is assigned by the first base station responding to a traffic channel assignment request transmitted via a control channel corresponding to the first base station, and then enters into a conversation status on the traffic channel, and wherein when an electric field strength, in mW, of the traffic channel is not larger than a first threshold value, or when a difference, in mW, between the electric field strength of the traffic channel and the electric field strength of the interference wave is not larger than a second threshold value, the mobile station terminates the operation of establishing the link and reissues the traffic channel assignment request, and when the electric field strength, in mW, of the traffic channel is larger than the first threshold value and the difference, in mW, between the electric field strength of the traffic channel and the electric field strength of the interference wave is larger than the second threshold value, the mobile station continues transmitting/receiving the burst signal to establish the link for the traffic channel, the interference wave being a reception signal level when no signal is received from the selected base station on the traffic channel, when the electric field strength, in mW, of the traffic channel is larger than the first threshold value, and the difference, in mW, between the electric field strength of the traffic channel and the electric field strength of the interference wave is larger than the second threshold value, the mobile station (i) transmits an idle burst to the first base station via the traffic channel, (ii) receives the idle burst subsequently returned by the first base station via the traffic channel, (iii) transmits a Set Asynchronous Balanced Mode to the first base station via the traffic channel, and (iv) receives an Unnumbered Acknowledgment from the first base station via the traffic channel.