Base station, mobile station, and communication method

A communication method implemented by a mobile communication system including a mobile station that intermittently performs a receiving operation during a cyclic reception period, and a base station that communicates with the mobile station,

• the communication method comprising:
• assigning a preamble to the mobile station by the base station;
• transmitting, in a plurality of directions, a start request signal containing the assigned preamble and requesting a start of a synchronization process between the mobile station and the base station while switching directions of a directional beam within the cyclic reception period by the base station;
• and
• performing, by the base station, a non-contention synchronization process using the preamble indicated by the received start request signal, when mobile station receives the start request signal.

A control circuitry to control a base station that communicates with a mobile station, the control circuitry comprising:

• a wireless transmitting/receiving circuitry configured to realize a function of a beam former and a wireless transmitter/receiver of the base station, wherein
• the beam former is configured to weight the amplitudes and phases of radio waves emitted from antennas, adjust the amplitudes and the phases, and simultaneously form directional beams in different directions, and
• the wireless transmitter/receiver is configured to perform a process of transmitting a signal to the mobile station, and to perform a process of receiving a signal transmitted from the mobile station;
• a wired transmitting/receiving circuitry configured to realize a function of the wired transmitter/receiver that is connected to a host device and other base stations via wired communication paths, and to communicate with the host device and the other base stations;
• and
• a processing circuitry configured to determine (DRX) state of the mobile station, transmit a start request signal requesting a start of a synchronization process during a reception period of the mobile station through a beam sweep while changing the directions of directional beams, and perform a non-contention synchronization process with the mobile station.

A computer program product comprising a non-transitory computer usable medium having a computer readable program that causes:

• a baseband signal processor to perform a modulation process on a signal to be transmitted to a mobile station, and a demodulation process on a signal received from the mobile station;
• a beam controller to select a direction of a directional beam and an antenna to be used for each direction, and cause a beam former to form the directional beam in the selected direction with the selected antenna;
• an L2 function circuitry to perform protocol processing for communicating with the mobile station;
• an assignor to assign a preamble for performing a non-contention synchronization process;
• a control information transmitter/receiver to transmit and receive a control message at a time of initial connection to the mobile station, determine a reception timing of a plurality of preambles and parameters for the mobile station to perform (DRX) control, and notify the mobile station of the reception timing and the plurality of parameters;
• and
• a DRX manager to manage the plurality of parameters for each mobile station to perform the DRX control, and determines the timing at which the mobile station can perform reception.