Kokusai Denshin Denwa Co., Ltd.

Kokusai Denshin Denwa Kabushiki Kaisha

Mitsuo Nohara

Fumio Takahata

Katsuyuki Yamazaki

Yoshio Takeuchi

Yasuo Hirata

A data scramble transmission system with a data transmission link coupled between sending and receiving ends is provided. The link adopts transmission frames each of which is constituted by data and control bits periodically added to the data. The system includes a scramble unit located at the sending end, for detecting each of the transmission frames of an input signal stream, for interchanging bit-stream positions of data portion in the detected transmission frame in accordance with a predetermined order to produce interchanged signal stream, and for outputting the interchanged signal stream, and a descramble unit located at the receiving end which receives the interchanged signal stream from the sending end, for detecting each of the transmission frames of the received interchanged signal stream, for reinterchanging bit-stream positions of data portion in the detected transmission frame so as to reconstitute the signal stream inputted into the scramble unit at the sending end, and for outputting the reconstituted signal stream.

Data scramble transmission system

An up-link power from an earth station in a satellite communication system is controlled to compensate rain attenuation caused in an up-link so that the transmission power of the earth station is adjusted according to the difference between the level of a received reference signal, which is sent from a reference earth station to the satellite, and the level of its own received signal which is transmitted to the satellite from itself and is received at its own station after being relayed by the satellite. A transmission power of the reference earth station is adjusted so that the level of the received reference signal at the satellite is constant.

Up-link power control in satellite communications system

A demand-assignment communication system is disclosed, in which a plurality of earth stations share a plurality of satellite communication channels in one satellite transponder frequency band, and in which a plurality of carriers with a plurality of transmission frequency bands determined according to transmission rate corresponding to plural kinds of communication circuits of different transmission rates are integrally handled and which, upon occurrence of a call from one of the earth stations to another, assigns to the call a satellite communication channel corresponding to the transmission frequency band necessary therefor. In accordance with the present invention, the frequency slot positions for the satellite communication channels and the order of assignment thereof are determined for each kind of transmission frequency bands necessary for the communication circuits, and each satellite communication channel is assigned to the frequency slot position therefor in the order of its assignment to comply with a request for assignment of one of the satellite communication channels to the call.

Demand-assignment communication system

In a frequency division multiple access (FDMA) communication system, a plurality of carrier frequencies relating to a predetermined frequency band for transmitting a PSK (phase shift keying) signal are provided on a frequency scale. When a service is a low bit rate signal, it is transmitted by using a single carrier frequency and its related frequency band. When a service is a high bit rate signal which can not be transmitted in a single carrier signal, the service signal is divided in to a plurality of low bit rate PSK signals, each of which is transmitted by using a single carrier frequency and the related frequency band.

Growing community of inventors

Tokyo, Japan

Mitsuo Nohara