Nec Corporation

Nippon Telegraph and Telephone Corporation

Matsushita Communication Industrial Co., Ltd.

Ntt Mobile Communications Network, Inc.

Tadao Hashimoto

Fumio Suzuki

Mitsuo Sato

Susumu Kojima

Yoshitoshi Murata

Noriaki Nagashima

Masahiko Hirono

Toshihiko Shibata

Kazushige Tanaka

Ryoji Hara

Yasuhiro Fujimura

A radio communication method includes (a) providing a mobile station and (b) changing a period. The mobile station can make a call through each of an independent system base station and an outdoor public system base station. The period is a period when a waiting operation to the independent system base station is performed. The period is changed based on a distance between the mobile station and the independent system base station.

Communication method of cordless telephone that can always make call as necessary and suppress unnecessary waiting operation to reduce consumption power and cordless telephone

In a mobile radio communication system, a mobile station has a field level decision section which outputs a decision signal when the electric field level of a received signal exceeds a threshold level. A controller sequentially sets a plurality of different threshold levels. In response to the decision signal from the decision section, synchronization to the received control signal begins. When the mobile station receives down-going control signals from a plurality of base stations, it selects the one having the highest field level, and then sets up synchronization to the signal selected.

Mobile radio communication system and channel control method therefor

In each radio base station of a cellular mobile communication network in which a mobile station is communicative with the radio base stations through a time division multiplex radio link, a transmitter/receiver serves as a synchronization system in cooperation with a base station control unit (35) to synchronize a down-link radio signal generated from a transmission frame generator at a transmission time with a like down-link radio signal transmitted from a different one of the radio base stations. The synchronization system has a received frame regenerator for detecting a reception time of one of frames of an up-link radio signal directed from the mobile station to the different station. A timing controller calculates a time difference between the transmission and the reception time. Controlled by the control unit in accordance with the time difference, the timing controller controls, in turn, the transmission time. Preferably, the time difference is stored in a memory and read out by the control unit when the received frame regenerator receives another of the up-link frames that next follows the above-mentioned one up-link frame.

Transmission timing control in a base station for cellular TDMA mobile

A method and arrangement of locating cordless units in a wide area cordless telephone system is disclosed. A service area is previously divided into a plurality of small service zones and, a plurality of cordless units are provided for establishing communications with a system controller via a plurality of access stations. The system controller locates the cordless units and stores therein location data thereof. Each of the cordless units also stores the location data thereof applied from the system controller. A cordless unit issues a request signal which includes cordless unit location data. The request signal is received at an access station which in turn checks to determine if the request signal applied thereto is issued from a cordless unit whose location data indicates a service zone belonging to a predetermined service zone group. In the event that the cordless unit location data applied to the access station is found to fall within the predetermined service zone group, the access station relays the request signal applied thereto, together with a signal level of the request signal, to the system controller.

Method and arrangement of locating cordless units in wide area cordless

In a cellular communications system, the quality of a signal transmitted over a first two-way connection from a mobile station via a first base station is compared with a threshold to determine whether a handoff is to be performed to a second, adjacent base station. When the quality of the transmitted signal becomes lower than the threshold, a second two-way connection is established from the mobile station to the second base station, and a switching request signal and an information-bearing signal are sent from the mobile station over both connections to a switching exchange. In response to the request signal, one directional path of the first connection is cleared to prevent a version of the signal passing through the first connection from reaching the destination station, and a first switching complete signal is sent through the other path of the first connection to the mobile station to allow it to clear the first connection and return a second switching complete signal. The other path of the first connection is then cleared in response to the second switching complete signal, leaving the second connection between the mobile station and the second base station.

Digital cellular switching system with means for securing uninterrupted

In a wide area cordless telephone system, an individual-call signal is generated if an incoming call from the telephone network is an individual call to one of cordless stations of a group and a group-call signal is generated if it is directed to all cordless stations of the group. A group of access units are associated with the cordless station of each group to establish a control channel and speech channels with the cordless stations. The access units respond to the individual-call signal by transmitting a speech channel identifier to one of the cordless stations through the control channel and transmitting a ringing signal through a speech channel specified by the speech-channel identifier. In response to the group-call signal, speech-channel identifiers are successively transmitted from the access units to the cordless stations through the control channel and group ringing signals are respectively sent to the cordless stations through speech channels specified by the speech-channel identifiers. In a modified embodiment, the cordless stations receive pairing identifiers each containing a pair of an access unit identifier and a cordless station identifier and transmit a response containing one pairing identifier that specifies the own station. The access units also receive pairing identifiers from the controller for detecting a match with those received from the cordless stations. If a match is detected by each access unit, it is entitled to send a speech-channel identifier to the cordless station which is specified by the matched identifiers.

Wide area cordless telephone system capable of receiving incoming group

In a radio communication network system for use in carrying out communication with a plurality of radio telephone sets in a service zone by the use of a control channel and a plurality of speech channels, a connecting equipment unit (CE) is selectively operable in cooperation with a radio control unit (RCU) in a speech mode of forming a speech path through a selected one of the speech channels and an additional mode of selectively monitoring the control and the speech channels. The additional mode may be divided into first and second control modes for allowing and rejecting reception of a call with the control channel monitored, respectively. Alternatively, either a rest mode or a combination of rest and initial program loading modes may be added to the additional mode. A plurality of the connecting equipment units may be located in a single service zone and selectively put into the speech and the additional modes with only one of the connecting equipment units kept in the first control mode.

Growing community of inventors

Tokyo, Japan

Tadao Hashimoto