Sumitomo Electric Industries, Limited

The Tokyo Electric Power Company, Incorporated

Asch Corporation

Seiji Hattori

Shinji Suzuki

Yoshizo Shibano

Yoshinobu Kobayashi

Akihide Kasukawa

Toshio Suzuki

Hiroshi Sahara

Naoki Fujisaki

Masashi Tonomura

Yoshihiro Murata

Hiroshige Kimura

In a two-way communication system having first and second communication terminals, a telephone apparatus at each terminal for two-way telephone service and a picture communication apparatus at each terminal for providing users with visual images of each other; the picture communication apparatus includes video cameras for generating video signals to be transmitted, display apparatus for displaying the visual images, a control apparatus for controlling transmission and reception of the video signals, and a line drawing input apparatus connected to the control apparatus for generating a line signal representing the line drawing and which is transmitted with the video signals from the control apparatus.

Picture communication apparatus

A mobile station receives radio waves from all signposts through the positioning channels while making communications using the voice channels. The signal levels of the radio waves thus received are subjected to comparison, so that a zone switching request is made to a signpost with the highest signal level, whereby a mobile station can make communication through that signpost which covers the zone where the mobile station is located, even while traveling. The positioning channels are so set that the frequencies assigned to the signposts are switched every frame in a time series mode, and none of the signposts transmit one and the same frequency at the same time. Therefore, the mobile station can receive radio waves from all the signposts without signal interference (which may be caused when a plurality of stations transmit signals equal in frequency). In the system of the invention, the transmission zones of adjacent signposts overlap each other. When a zone switching request is made, a mobile station can therefore make communications with both of the signposts; that is, the switching of zones can be positively achieved.

Mobile communication system

A mobile communication system is provided wherein a plurality of signposts enable communications among mobile stations and a switching system in a predetermined communicating area, and are connected through a transmission network connected to a fixed network according to the invention, each of the signposts has dual zone communications ability including a communicating area which overlaps the communicating areas or adjacent signposts, and a zone switching signal area which does not overlap the zone switching signal areas of adjacent signposts. The signpost and mobile stations, jointly detect on-going signal levels of the mobile station, and communication area switching operation are carried out as needed. In the mobile communication system of the invention, a transmitting and receiving equipment can be a single transceiver which switches over the frequencies to communicating channel frequencies and to zone switching controlling frequencies.

Growing community of inventors

Tokyo, Japan

Seiji Hattori