Iwatsu Electric Company Ltd.

Sadao Itoh

In a mobile communication system in which signals are temporally compressed into time slots of a frame structure, a composite signal such as a telephone signal or data signal is hybrid-modulated using the same radio carrier wave, whereby diversity transmission/reception are available. The telephone signal is frequency-modulated using a single time slot of a single radio communication channel which has been allocated between a mobile transceiver and a radio base station. The frequency-modulated signal is again amplitude-modulated by the same telephone signal so that diversity transmission/reception is available.

Diversity communication method of time-division, time-compressed

A portable telephone system is disclosed in which a plurality of i-th class exchanges, which accommodate key service units of a plurality of portable telephone sets present in each service area, and at least one (i+1)th class exchange which accommodates the plurality of i-th class exchanges through junction lines, are stratified to form an exchange system so that i=1, 2, 3, . . . , and so that the (i+1)th class exchange covers all service areas. The exchange system has a function whereby information which specifies the home area of each portable telephone set and the portable telephone set in distinction from each other is registered in the i-th class exchange and the (i+1)th class exchange, which administer the home area.

Portable telephone system

A mobile body communication method using a gateway exchanging unit for exchanging a communication between a radio base station and a plurality of mobile radio units, the radio station constituting a service area covering a plurality of zones, the mobile radio units moving across the plurality of zones and using a radio channel to communicate with the radio base station, the radio channel carrying time-division time-compressed signals in time slots constituting a frame, the method comprising the steps of, determining a level of a radio signal to be used in a communication between the radio base station and the mobile radio unit based on a non-simultaneous load advantage obtained by the time-division time-compressed signals, transmitting a signal to be transmitted while causing an amplitude distribution thereof to be compressed within a desired range by a syllabic compressor, and subjecting a received signal to an amplitude distribution recovering process by a syllabic expander.

Time-division communication method for mobile bodies and system using

A portable telephone system is disclosed in which a plurality of i-th class exchanges, which accommodate key service units of a plurality of portable telephone sets present in each service area, and at least one (i+1)th class exchange which accommodates the plurality of i-th class exchanges through junction lines, are stratified to form an exchange system so that i=1, 2, 3, . . . , and so that the (i.1)th class exchange covers all service areas. The exchange system has a function whereby information which specifies the home area of each portable telephone set and the portable telephone set in distinction from each other is registered in the i-th class exchange and the (i+1)th class exchange, which administer the home area.

Portable telephone system using stratified exchange system

A mobile communication system based on a time division communication system comprising: mobile radio units for transmitting and receiving time-compressed and segmented signals by a radio channel allocated to time slots; radio base stations to which a communicable time slot is previously allocated so as to communicate using only a specific time slot of those time slots of the radio channel when the mobile radio units moves across one of service areas that are disposed so as to overlap at least partially with one another, the time slot allocated to one radio base station being different from that allocated to another radio base station; and gateway exchange units for exchanging communications between the mobile radio units and the radio base stations and for connecting the radio base stations to a public switched telephone network.

Growing community of inventors

Kanagawa, Japan

Sadao Itoh