Ntt Docomo, Inc.

Ntt Mobile Communications Network, Inc.

Masafumi Hata

Yasuyuki Watanabe

Motoshi Tamura

Takaaki Sato

Junichiro Hagiwara

Kazufumi Yunoki

Katsuhiko Yamagata

Yoshiyuki Yasuda

Mutsumaru Miki

Takuya Hamajima

Akihiro Uchikoshi

Nobuhide Uchiyama

Nobutaka Ishikawa

Daisuke Igarashi

Kenya Kusunose

Akiko Okamoto

Minami Ishii

Seizo Onoe

Yoshihiro Ishikawa

Etsuhiro Nakano

Akiko Green Gables C-101 12-14 Okamoto

Nobutaka 202 Bell Light Nokendai Ishikawa

When a network pages the temporary user mobile identifier of a mobile station, the mobile station sends a response to the network. Next, the network checks the authenticity of the user using a ciphering key, corresponding to the temporary user mobile identifier and a random number. If the temporary user mobile identifier is authenticated, a normal incoming call acceptance procedure is executed. If the mobile station is authenticated although the temporary user mobile identifier is wrong, the network reassigns a new temporary user mobile identifier to the mobile station and stops the current communication. In communication, the network and the mobile station mutually notify encipherment-onset time and negotiate about encipherment manner with each other. In addition, diversity handover is commenced upon a call attempt. Furthermore, if a branch replacement is necessary, the current branch is replaced by new branches capable of executing the diversity handover. Additionally, when a new call occurs to or from the mobile station capable of treating a plurality of calls simultaneously, the mobile station uses the same branch structure and the same communication frequency band for all of calls. Additionally, when a new call occurs to or from the mobile station capable of treating a plurality of calls simultaneously, a branch structure and a communication frequency band, which can continue all of the calls, are selected and used. Therefore, the mobile communications system is suitable for transmission of various sorts of data in accordance with the development of multimedia.

Method and system for mobile communications

When a new call occurs to or from the mobile station capable of treating a plurality of calls simultaneously, the mobile station uses the same branch structure and the same communication frequency band for all of calls. Additionally, when a new call occurs to or from the mobile station capable of treating a plurality of calls simultaneously, a branch structure and a communication frequency band, which can continue all of the calls, are selected and used.

When a network pages the temporary user mobile identifier of a mobile station, the mobile station sends a response to the network. Next, the network checks the authenticity of the user using a ciphering key, corresponding to the temporary user mobile identifier and a random number. If the temporary user mobile identifier is authenticated, a normal incoming call acceptance procedure is executed. If the mobile station is authenticated although the temporary user mobile identifier is wrong, the network reassigns a new temporary user mobile identifier to the mobile station and stops the current communication. In communication, the network and the mobile station mutually notify encipherment-onset time and negotiate about encipherment manner with each other. In addition, diversity handover is commenced upon a call attempt. Furthermore, if a branch replacement is necessary, the current branch is replaced by new branches capable of executing the diversity handover. Additionally, when a new call occurs to or from the mobile station capable of treating a plurality of calls simultaneously, the mobile station uses the dental same branch structure and the same communication frequency band for all of calls. Additionally, when a new call occurs to or from the mobile station capable of treating a plurality of calls simultaneously, a branch structure and a communication frequency band, which can continue all of the calls, are selected and used. Therefore, the mobile communications system is suitable for transmission of various sorts of data in accordance with the development of multimedia.

A base station of a second system performs communication using a frequency adjacent to a frequency employed by communication between a base station and a mobile station of a first system. When the mobile station is close to the base station , the communication of the base station undergoes interference by the leakage power of the mobile station . To avoid the interference, the transmission is halted of the mobile station of the first system, which provides the interference by the leakage power.

Interference avoidance radio communications system

A decision is made as to whether a radio base station acting as an interference source is present in a macrocell or microcell, so that the interference from a mobile station transmitting high power can be presented in advance. The base station inserts its transmission power value of a forward broadcast channel into broadcast information. A newly installed base station C, receiving a forward frequency band, measures the received level of the broadcast channel, and captures the transmission power value. When the transmission power value is large, the threshold value is reduced (THRb), and when the transmission power value is small, the threshold value is increased (THRa). If the received level L is less than the threshold value, a decision is made that the channel is available.

Communication channel selecting method and base station device

Growing community of inventors

Yokosuka, Japan

Masafumi Hata