Abstract: An interface, apparatus, and method are described for communication between a radio control (REC) node and first and second radio equipment (RE) nodes in a radio base station that transceives information over radio interface using multiple antenna carriers. The REC node is separate from and coupled to the first RE node by a first transmission link, and the second RE node coupled to the first RE by a second transmission link. Both control information and user information intended for communication between the REC node and the first RE node and the REC and the second RE node are conveyed over the first transmission link. The first RE node also conveys information between the REC and second RE node. Many advantageous features are described.

Abstract: An interface, apparatus, and method are described for communication between a radio equipment control (REC) node and first and second radio equipment (RE) nodes in a radio base station that transceives information over radio interface using multiple antenna carriers. The REC node is separate from and coupled to the first RE node by a first transmission link, and the second RE node coupled to the first RE by a second transmission link. Both control information and user information intended for communication between the REC node and the first RE node and the REC and the second RE node are conveyed over the first transmission link. The first RE node also conveys information between the REC and second RE node. Many advantageous features are described.

Abstract: A transmission device includes signal synthesizer 16 that replaces the least significant bits of a plurality of transmission and reception target data that are digital signals with bit data of a desired control signal that is a digital signal, and serial signal converter 17 that converts the output signal from the signal synthesizer into a serial signal and transmits the serial signal. On the other hand, a reception device includes parallel signal converter 21 that converts the received serial signal into a parallel signal to acquire transmission and reception target data, and signal separator 23 that extracts the bit data of the control signal from the respective least significant bits of transmission and reception target data output by parallel signal converter 21.

Abstract: A communication amount monitoring circuit (124) monitors a transmission buffer (123) to which communication data (122) is input, and discriminates the magnitude of the amount of communication data. If the amount of information per unit time is relatively large, information is read out from the transmission buffer in accordance with a chip clock. This information is modulated as communication data (137) by a modulator (139) and transmitted. If the amount of information is relatively small, information is read out from the transmission buffer (123) in accordance with a clock obtained by frequency-dividing the chip clock. This information is exclusive-ORed with a spreading code generated by using the chip clock and is then modulated by a modulator (139). The resultant data is transmitted as communication data (137).

Abstract: A satellite communication transmission control system includes one central station, a plurality of small aperture terminals, and one communication satellite serving as a repeater for the central and aperture terminals. This system performs communication via a frequency division multiple access communication channel. The central station includes a modulator for transmitting via a common channel a signal for controlling/monitoring the small aperture terminals on the basis of a stable clock signal. Each aperture terminal includes a modulator, transmission frequency converter, antenna/RF device, reception frequency converter, demodulator, and frequency comparator. The modulator modulates communication information. The transmission frequency converter frequency-converts a modulated wave from the modulator into a carrier signal (modulated carrier). The reception frequency converter frequency-converts the modulated carrier.

Abstract: A vacancy information search system includes a vacancy information storage unit, reserved business entity storage unit, priority setting unit, and search unit. the vacancy information storage unit stores business entity vacancy information. The reserved business entity storage unit stores the log of a business entity reserved by a user. The priority setting unit sets a priority given by the user for the reserved business entity stored in the reserved business entity storage unit. The search unit accesses the vacancy information storage unit in response to a request from the user and searches for vacancy information of the reserved business entity of the user, which is stored in the reserved business entity storage unit, in order of priorities set for the reserved business entity.

Abstract: A VSAT station and a VSAT communication system have a demand assign multiple access function for keeping a transmission path only for a required period of time to effectively use frequencies. The VSAT station has a transmission controller for temporarily reading and storing communication data 41 to be transmitted in buffer 42 and outputting the stored communication data as transmission data 43 after elapsed of a given period of time. Communication traffic monitoring circuit 45 monitors the stored amount of communication data in buffer 42 and outputs communication path selecting signal 46. Transmission data switching circuit 44 selects a transmission circuit to transmit the transmission data. If the communication traffic between communicating stations is increased, then dedicated line 49 is established in another frequency band. If CSC line 48 is congested, then dedicated line 49 is established to reduce the burden on CSC line 48.

Abstract: In a digital satellite communications system for communicating data between a HUB station and a plurality of VSATs (Very Small Aperture Terminals) or between the VSATs via a communications satellite, each VSAT comprises: a digital signal processing section for demodulating signals received by the VSAT; ROM for storing a default program for letting the digital signal processing section execute signal demodulation at start-up of the VSAT; rewritable memory for storing an operation program for letting the digital signal processing section execute signal demodulation after the start-up of the VSAT; an operation program download section for obtaining the operation program by downloading the operation program from the HUB station; an error check/rewriting section for conducting error check to the downloaded operation program until an errorless operation program is obtained by the download and storing the errorless operation program in the rewritable memory; and a switching control section for switching a program wh

Abstract: A communication amount monitoring circuit (124) monitors a transmission buffer (123) to which communication data (122) is input, and discriminates the magnitude of the amount of communication data. If the amount of information per unit time is relatively large, information is read out from the transmission buffer in accordance with a chip clock. This information is modulated as communication data (137) by a modulator (139) and transmitted. If the amount of information is relatively small, information is read out from the transmission buffer (123) in accordance with a clock obtained by frequency-dividing the chip clock. This information is exclusive-ORed with a spreading code generated by using the chip clock and is then modulated by a modulator (139). The resultant data is transmitted as communication data (137).

Abstract: A VSAT station and a VSAT communication system have a demand assign multiple access function for keeping a transmission path only for a required period of time to effectively use frequencies. The VSAT station has a transmission controller for temporarily reading and storing communication data 41 to be transmitted in buffer 42 and outputting the stored communication data as transmission data 43 after elapsed of a given period of time. Communication traffic monitoring circuit 45 monitors the stored amount of communication data in buffer 42 and outputs communication path selecting signal 46. Transmission data switching circuit 44 selects a transmission circuit to transmit the transmission data. If the communication traffic between communicating stations is increased, then dedicated line 49 is established in another frequency band. If CSC line 48 is congested, then dedicated line 49 is established to reduce the burden on CSC line 48.

Abstract: A satellite communication transmission control system includes one central station, a plurality of small aperture terminals, and one communication satellite serving as a repeater for the central and aperture terminals. This system performs communication via a frequency division multiple access communication channel. The central station includes a modulator for transmitting via a common channel a signal for controlling/monitoring the small aperture terminals on the basis of a stable clock signal. Each aperture terminal includes a modulator, transmission frequency converter, antenna/RF device, reception frequency converter, demodulator, and frequency comparator. The modulator modulates communication information. The transmission frequency converter frequency-converts a modulated wave from the modulator into a carrier signal (modulated carrier). The reception frequency converter frequency-converts the modulated carrier.

Abstract: In a digital satellite communications system for communicating data between a HUB station and a plurality of VSATs (Very Small Aperture Terminals) or between the VSATs via a communications satellite, each VSAT comprises: a digital signal processing section for demodulating signals received by the VSAT; ROM for storing a default program for letting the digital signal processing section execute signal demodulation at start-up of the VSAT; rewritable memory for storing an operation program for letting the digital signal processing section execute signal demodulation after the start-up of the VSAT; an operation program download section for obtaining the operation program by downloading the operation program from the HUB station; an error check/rewriting section for conducting error check to the downloaded operation program until an errorless operation program is obtained by the download and storing the errorless operation program in the rewritable memory; and a switching control section for switching a program wh

Abstract: A conference station for use in a satellite conferencing system is arranged to receive communications on at least one satellite communication channel having a given frequency and to transmit communications on at least one satellite communication channel having a given frequency. The conference station itself controls whether or not the conference station can transmit on a satellite communication transmission channel by enabling transmission on a communication channel only when the conference station itself determines that that satellite communication channel is free for use or unoccupied. The conference station is also responsive to data signals received from a conference control station to adjust the satellite communication channel frequency or frequencies on which the conference station is able to receive or transmit signal. The conference station may form a part of a group of similar conference stations to which the same communication channels are allocated.

Abstract: Radiated from each orbiting satellite of a satellite communication network to M cells (M representing an integer, such as thirty-seven) covered with a predetermined solid angle on the earth, M spot beams are identified by M identification codes. In an earth station which may be a portable unit, a burst signal transmitter device (31) comprises a receiver part (35) receiving one of the spot beams as a received beam at a reception time, to recognize as a recognized code one of the identification codes that identifies the received beam, and a transmitter part (45) for transmitting burst signals at a transmission time delayed from the reception time by an offset amount selected by the recognized code from M offset amounts predetermined for the identification codes. Preferably, the M offset amounts are stored in a memory (43).

Abstract: A frequency error occurring in a repeater station and a receiving side radio station is determined by using a dummy signal received from the repeater station, and is stored as frequency control data corresponding to the frequency error into a memory. By controlling a reception frequency based on the stored frequency control data, a data signal received from the repeater station is compensated for the frequency error. A relatively large frequency error such as the common frequency error occurring in the satellite and the downconverter of the receiving side can be eliminated effectively.

Abstract: In a control system being provided with a local oscillator (42) and being for controlling a demodulating arrangement (43, 44, and 45) demodulating a desired one of modulated signals in accordance with a demodulating frequency, produced by a sweeping operation of the local oscillator, into a demodulated signal having a unique word and an identification number which are carried by the desired modulated signal, a unique word detecting circuit (47) detects the unique word to produce a unique word detection signal. A number comparing circuit (48) compares the identification number with a desired one of predetermined numbers to produce a number coincidence signal when the identification number coincides with the desired number. In response to presence and absence of each of the number coincidence and the unique word detection signals, an oscillator control circuit (49) controls the sweeping operation of the local oscillator.

Abstract: An available frequency range previously assigned to the communication system is divided into a plurality of subranges each including a plurality of frequency channels to which channel identifiers are assigned, respectively. The channel identifiers are repeatedly assigned to all the frequency channels in the subranges. In such a channel assignment, a transmitting side transmits a signal including a desired channel identifier corresponding to a desired frequency channel. At a receiving side, after detecting a frequency acquisition of the demodulator, the desired channel identifier is detected based on the received signal when the frequency acquisition of the demodulator is detected. When the frequency acquisition of the demodulator is detected and the desired channel identifier is detected, a local oscillation frequency sweeping for demodulator is locked to receive the signal from the transmitting side.

Abstract: In a communication system for transmitting and receiving burst signal between a round-trip satellite and a ground station, upon transmission of a transmitting burst signal from the round-trip satellite, a standard time upon transmission is added to the transmitting burst signal. In the ground station, the time data added to the transmitting burst data is extracted and compared with the standard time upon reception to derive a transmission delay period. A transmission timing of a burst signal to be transmitted from the own station is controlled depending upon the transmission delay period. By this, even when a distance between the ground station and the round-trip satellite is varied, overlapping of the burst signals in the time slots on the same time axis can be successfully avoided. Also, a guard time can be shortened to contribute for improvement of the transmission efficiency.

Abstract: A transmission apparatus for an orbiting satellite which can establish stabilized frame synchronization even if the distance between the round-trip satellite and a communications terminal varies and which can minimize the displacement between a frame signal received on the ground and another frame signal generated in a communications terminal. The transmission apparatus comprises M (M is an integral number equal to or greater than 2) composers for forming frame signals, M transmitters for outputting M spot beams having different radiation directions, and M delay circuits interposed between the composers and the transmitters. The delay times of the delay circuits are set so that they are long where the radiation angles of the corresponding spot beams are small, but they are shorter where the radiation angles are larger.

Abstract: At the transmit end of a communications system, a convolutional code of a multiplex of an information-bearing signal and a unique word is modulated upon a transmitted carrier. At the receive end, the transmitted carrier is demodulated with a local carrier to detect the convolutional code. The error rate of a decoded version of the convolutional code is determined, and an out-of-FEC-sync signal is produced when the error rate is higher than a threshold value. Unique words are detected from the decoded signal and counted during a prescribed time interval to produce an out-of-frame-sync signal when the count falls below a threshold. The frequency of the local carrier is swept in the presence of the out-of-FEC-sync signal. When the signal ceases to exist, a timeout period is set, and the local carrier frequency is swept again when the timeout period expires during the presence of the out-of-frame-sync signal.