Hitachi, Ltd.

Hitachi Communication Technologies, Ltd.

Daiho Kasai

Masaaki Yano

Ryosuke Kurata

Kenji Yamazaki

Takanori Moritomo

Hirokazu Inayoshi

Tomoyasu Sakaguchi

If a wireless resource congestion occurs, the wireless resources of the entire system are used efficiently to reduce a disconnection of communication with a congested sector and a state in which a new call cannot be originated nor terminated. A base station control apparatus compares the wireless resource usage amount of each sector of each base station with values stored in a wireless resource threshold table. If a sector of a base station is in the light congestion state, the neighbor search window size of a sector specifying the congested sector as a neighbor is changed to restrict a soft hand-over to the congested sector. If a sector of a base station is in the heavy congestion state, a mobile station which is communicating in the congested sector and receiving radio waves of another sector with stability is subjected to a forced soft hand-over.

Congestion control method for wireless communication system and base station control apparatus

A neighbor sector is automatically set to effectively perform soft handover. A base station corresponding to a first sector to communicate with a wireless terminal and a base station corresponding to a second sector to start communication with the wireless terminal due to movement of the wireless terminal or the like transmit a terminal identifier acquired from the wireless terminal, a time and a sector identifier to a base station control part (control part in the following). The control part successively stores the received sector identifier into a table correspondingly to the terminal identifier and the time received from the base station. Besides, the control part refers to the table, judges whether different sector identifiers are stored in a previously determined time range, regards a pair of the two different sector identifiers as neighbor sector candidates and counts the number of times they are regarded as the neighbor sector candidates. With respect to the neighbor sector candidates in which the counted number of times is a threshold or more, the control part transmits, to the base station corresponding to one sector of the neighbor sector candidates, a change request including the neighbor sector information concerning the other sector.

Mobile communication system and base station control apparatus

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Fujisawa, Japan

Daiho Kasai