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1. 发明专利

JPH089455A RADIO COMMUNICATION SYSTEM AND COMMUNICATION EQUIPMENT 失效
公开(公告)号：JPH089455A
公开(公告)日：1996-01-12
申请号：JP13985694
申请日：1994-06-22
申请人： HITACHI LTD
发明人： TAKIYASU YOSHIHIRO , AMADA EIICHI , ISHIDO TOMOAKI , ISHII GENICHI , SHIGESA HIDEHIKO , ADACHI SHUICHI
IPC分类号： H04L12/28 , H04W16/02 , H04W84/12 , H04W92/20 , H04Q7/36
摘要： PURPOSE:To prevent communication efficiency from degrading even when a cell is overlapped by hopping the carrier wave frequency of a radio frame inside the present cell at each base station at prescribed timing based on control information. CONSTITUTION:Five base stations #1-#5 are mutually connected by the backbone, the base station $5 becomes a main base station and transmits an inter-base station control frame to the backbone, and the other four base stations #1-#4 to be the slave base stations received with the control frame hop the carrier frequency synchronously with the main base station. In this case, the base station #5 uses a sub-channel 9 and the other base stations #4-#1 respectively use sub-channels 7, 5, 3 and 1. Each base station switches the sub-channel to be used at prescribed hop timing while selecting the next sub-channel in a clock- wise direction for each frame. The switching of the sub-channel can be simultaneously performed by the plural base stations synchronously with a command from the main base station.

2. 发明专利

JPH06261020A FREQUENCY HOPPING COMMUNICATIONS SYSTEM AND COMMUNICATIONS EQUIPMENT 失效
公开(公告)号：JPH06261020A
公开(公告)日：1994-09-16
申请号：JP4488093
申请日：1993-03-05
申请人： HITACHI LTD
发明人： ISHIDO TOMOAKI , AMADA EIICHI , TAKIYASU YOSHIHIRO , ISHII GENICHI , SHIGESA HIDEHIKO , ADACHI SHUICHI
IPC分类号： H04B1/7143 , H04J13/00 , H04W28/04 , H04W76/02 , H04B7/26
摘要： PURPOSE:To apply an inexpensive synthesizer of a small size and low power consumption to the communications system by making a hopping interval coincident with a frame length close to a fading fluctuation period. CONSTITUTION:A modulation signal received by a transmission reception antenna 101 is inputted to a frequency mixer 103 and mixed with an output of a synthesizer 111, a base band signal is extracted from an LPF, a received clock is extracted and inputted to a demodulation section 151, from which a reception clock is generated. A microprocessor 113 reads a reception signal demodulated according to the extracted reception clock and stores the signal to a memory 114. The processor 113 transfers data read from the memory 114 or the like to a phase modulation section 152. The phase modulation section 152 generates a BPS base band signal and inputs it to a mixer 107. The mixer 107 mixes the signal with an output of the synthesizer 111 to provide an output. A PN coder 112 hops the oscillating frequency of the synthesizer 111 in response to a command of the processor 113.

3. 发明专利

JPH0677963A COMMUNICATION SYSTEM AND TERMINAL EQUIPMENT 失效
公开(公告)号：JPH0677963A
公开(公告)日：1994-03-18
申请号：JP4487993
申请日：1993-03-05
申请人： HITACHI LTD
发明人： TAKIYASU YOSHIHIRO , AMADA EIICHI , ISHIDO TOMOAKI , ISHII GENICHI , SHIGESA HIDEHIKO , ADACHI SHUICHI
IPC分类号： H04Q7/38 , H04B7/26 , H04J3/16 , H04L12/28 , H04Q1/30 , H04Q3/58
摘要： PURPOSE:To provide a multiplex access system impartial in plural terminals and high in communication efficiency. CONSTITUTION:A slave equipment transmits the number of fragments and the present address to a request area R2 of a communication frame 30, and a master equipment transmits the address of the slave equipment permitted transmission for each slot 38i in an information transfer area R4 composed of the plural pairs of fragment slots 38 and response slots 39. The slave equipment transmits a destination address 52 and data 54, and a destination equipment transmits the response to the slot 38i. When the master equipment detects the destination equipment fails the reception, the data are transmitted again in the next slot 38i+1. The right of transmission to be reserved and the maximum number of transmitting data in the cycle are controlled by a base station according to the request of the terminal.

4. 发明专利

JPH0946387A DIGITAL MODULATOR AND METHOD FOR CONTROLLING TRANSMISSION OUTPUT 失效
公开(公告)号：JPH0946387A
公开(公告)日：1997-02-14
申请号：JP19445095
申请日：1995-07-31
申请人： HITACHI LTD
发明人： ISHII GENICHI , ISHIDO TOMOAKI , ADACHI SHUICHI
IPC分类号： H04L27/00 , H04L27/20 , H04L27/36
摘要： PROBLEM TO BE SOLVED: To obtain a quadrature amplitude modulator which is capable of controlling the rise and fall of the waveform of a modulated signal and simplifying its composition. SOLUTION: The sampling rate which is four times as fast as those of the carrier waves cosωt and sinωt of an intermediate frequency is adopted, the filtering outputs 209 of I and Q components are alternately taken out from a filter circuit 202 inputting I and Q signals imparted from an encoding circuit 200 and the outputs are supplied to an upconvert/aperture correction circuit 203. The filter circuit 202 is composed of plural ROM storing the data of waveform shaped result, plural shift registers converting the I and Q signals into each ROM address, a zero output generation circuit and a selector selecting a ROM output and a zero output. Each stage of the shift registers outputs the preset value according to a control signal and performs the rise control at the time of transmission and the fall control at the time of termination.

5. 发明专利

JPH07170227A RADIO DATA COMMUNICATION SYSTEM 失效
公开(公告)号：JPH07170227A
公开(公告)日：1995-07-04
申请号：JP31626293
申请日：1993-12-16
申请人： HITACHI LTD
发明人： ISHII GENICHI , AMADA EIICHI , SHIGESA HIDEHIKO , TAKIYASU YOSHIHIRO
IPC分类号： H04B7/06 , H04B7/26
摘要： PURPOSE:To provide a radio data communication system which can secure the best state of communication with a mobile terminal and can validly prolong communicatable time. CONSTITUTION:A base station equipment 10 is provided with a phased array antenna 20 and a controller for the same, mobile terminals 40 are provided with fully directional antennas 50, the move of each mobile terminal 40 is detected at the base station equipment 10, and the beam direction of the antenna 20 is controlled while following the position movement. Thus, the power of the mobile station caused by antenna gain can be saved, multipath interference caused by the direction selectivity of the antenna can be reduced, and communication disable time related to antenna switch processing can be shortened.

6. 发明专利

JPH07143566A RADIO NETWORK SYSTEM 失效
公开(公告)号：JPH07143566A
公开(公告)日：1995-06-02
申请号：JP28786393
申请日：1993-11-17
申请人： HITACHI LTD
发明人： ADACHI SHUICHI , SHIGESA HIDEHIKO , AMADA EIICHI , TAKIYASU YOSHIHIRO , ISHIDO TOMOAKI , ISHII GENICHI
IPC分类号： H04B7/26 , H04Q7/38 , H04Q7/34
摘要： PURPOSE:To more exactly recognize a communication state by installing a transmission state display part at a terminal equipment in addition to a reception state display part. CONSTITUTION:Terminal equipments 100a and 100b are respectively provided with reception state display parts 170a and 170b, transmission state display parts 210a and 210b, external transmission power level setting parts 240a and 240b, and switches 250a and 250b. The siwtches 250a and 250b are changeover switches for setting whether transmission power is automatically controlled or manually controlled. Thus, the terminal equipments 100a and 100b display the reception states on the reception state display parts 170a and 170b and additionally transmit information for measuring the transmission states to a base station 300, the base station 300 receives this information from the terminal equipments 100a and 100b and transmits the received result to the terminal equipments 100a and 100b, and the terminal equipments 100a and 100b display the transmission states of the present terminal equipments based on that received result. Thus, the communication states of the terminal equipments 100a and 100b can be grasped at real time.

7. 发明专利

JPH08298682A RADIO COMMUNICATION SYSTEM AND COMMUNICATION EQUIPMENT 失效
公开(公告)号：JPH08298682A
公开(公告)日：1996-11-12
申请号：JP10343895
申请日：1995-04-27
申请人： HITACHI LTD
发明人： ISHIDO TOMOAKI , ISHII GENICHI , ADACHI SHUICHI
IPC分类号： H04L7/00 , H04B7/26 , H04L7/04 , H04L7/10 , H04L27/38 , H04W56/00 , H04W72/04 , H04W92/00 , H04Q7/36
摘要： PURPOSE: To speed up the setting of AGC, a phase, etc., on the receiving side, to improve the efficiency of a frame and to reduce the error rate of a frame by setting up a prescribed information field in a preamble area in a low frequency hopping communication system using a multi-valued orthogonal amplitude modulation system. CONSTITUTION: A transmitting station switches the frequency of a synthesizer in accordance with a set frequency hopping pattern, successively transmits respective fields of a ramp 701, receiving power measurement 702 and carrier reproduction 703 in a preamble area 741 and then transmits an information transfer area. When a non-modulated wave with an envelope of fixed size is used for the field 702 for setting up AGC, averaging time can be shortened and field length can also be shortened. The field 703 can be detected by using a non-modulated wave without generating ambiguity of phases between a reproduced carrier and a received wave and a timing extracting field 704 charges the phase of a carrier by π in each symbol and maximizes a phase change on a symbol boundary to improve the detection sensitivity of phase shift.

8. 发明专利

JPH0758749A RADIO LAN DEVICE 失效
公开(公告)号：JPH0758749A
公开(公告)日：1995-03-03
申请号：JP20389193
申请日：1993-08-18
申请人： HITACHI LTD
发明人： TAKIYASU YOSHIHIRO , AMADA EIICHI , ISHII GENICHI
IPC分类号： H04L12/28
摘要： PURPOSE:To obtain a radio LAN device which can easily be connected to an either radio or wired medium and usable even in environment wherein an error occurs like a burst by inserting an IC card for a wired LAN into a slot of a terminal which has a tail type IC card interface and connecting a radio LAN controller thereto by an AUI. CONSTITUTION:The IC card 7b of a wired LAN device is diverted to the terminal which has the IC card slot and a tail part which includes the control part for the radio LAN is connected by an AUI connector 9 to constitute the radio LAN device. The ROM 14 on the IC card 7b stores card attribute information on the kind of this IC card 7b, the MAC address of the terminal, etc. The MAC address of the terminal stored in the ROM 14 is used as the identifier of a radio MAC. An address management part 29 knows the transmission source address of a sent packet through a signal line 31 and sets the address in an address memory 28 using an SRAM.

9. 发明专利

JPH06311160A RADIO COMMUNICATION SYSTEM AND RADIO TERMINAL EQUIPMENT 失效
公开(公告)号：JPH06311160A
公开(公告)日：1994-11-04
申请号：JP9406693
申请日：1993-04-21
申请人： HITACHI LTD
发明人： AMADA EIICHI , TAKIYASU YOSHIHIRO , ISHIDO TOMOAKI , ISHII GENICHI , SHIGESA HIDEHIKO , ADACHI SHUICHI
IPC分类号： H04L12/28 , H04L12/46 , H04W52/02 , H04W74/04 , H04W74/08 , H04W84/12 , H04W88/08
摘要： PURPOSE:To reduce power consumption by controlling the power of a transmitter/receiver in radio LAN. CONSTITUTION:The addresses of data transmitted by a frame are collectively displayed at the head of the frame by using the frame of a fixed length. The transmitter-receiver of a terminal cuts the power of reception parts 807 and 808 at unnecessary time based on the information by making a transmission/ reception part 802 control a power control part 809. Thus, power consumption can be reduced by outing off the power of the reception part when received data does not exist.

10. 发明专利

JPH06261043A RADIO CHANNEL LAN SYSTEM AND ITS CONTROL METHOD 失效
公开(公告)号：JPH06261043A
公开(公告)日：1994-09-16
申请号：JP4489493
申请日：1993-03-05
申请人： HITACHI LTD
发明人： SHIGESA HIDEHIKO , AMADA EIICHI , TAKIYASU YOSHIHIRO , ISHIDO TOMOAKI , ISHII GENICHI , ADACHI SHUICHI
IPC分类号： H04L12/28 , H04L12/46 , H04W4/06 , H04W4/16 , H04W8/02 , H04W8/26 , H04W12/00 , H04W12/06 , H04W12/08 , H04W24/00 , H04W28/04 , H04W60/00 , H04W72/04 , H04W74/00 , H04W84/12 , H04W88/08 , H04B7/26 , H04Q7/04
摘要： PURPOSE:To attain re-transmission in a MAC layer by a base station equipment by providing a mobile terminal equipment management database and a mobile terminal equipment verification database to the base station equipment and providing a management source recognition database to a mobile terminal equipment respectively. CONSTITUTION:A base station equipment 10 executes re-transmission only to a mobile terminal equipment 20 registered in a mobile terminal equipment management database. Then since no re-transmission is applied to the mobile terminal equipment 20 not under the management of the base station equipment 10, useless communication is not executed. Furthermore, the base station equipment 10 collates the mobile terminal equipment management database with a mobile terminal equipment verification database and permits the registration of the mobile terminal equipment management database only to the mobile terminal equipment registered already in the mobile terminal equipment verification database. Since number of the mobile terminal equipments 20 under the management of the base station equipment 10 is limited, collision between transmission requests by the mobile terminal equipments 20 is reduced.

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