Hitachi, Ltd.

Hirokazu Inayoshi

Akinori Asahara

Michio Morioka

Takanori Moritomo

Kenji Naka

Masaaki Yano

Daiho Kasai

Tomoyasu Sakaguchi

A map distribution system includes a map distribution server that distributes map data to a navigation device. The server includes a first table having entries that each include update data in correspondence with an ID for the update data and an ID for each other update data upon which the update data depends, a second table having entries that each include an area ID of an area of the map data in correspondence with a version of the area and the ID for each update data that is applied in the version of the area, and an update manager that refers to the second table to select the ID for each update data required for updating an area selected based on input from the navigation device and the required ID for each other update data upon which any update data required for updating the area selected depends.

Map data distribution system

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

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Kawasaki, Japan

Hirokazu Inayoshi