Showing papers on "Base station published in 1980"

Mobile location using signal strength measurements in a cellular system

Abstract: In a high-capacity mobile telephone system using cellular technology, a mobile location technique which determines the radio zone in which a moving vehicle exists is one of the most important techniques for the system control. A mobile location technique using a signal strength measurement scheme is described. The probability that a mobile is judged to exist in a certain zone (zone selection rate) is first defined. Dependency of this rate on land mobile propagation characteristics is then discussed in detail. A field test for the justification of this location technique was carried out in the Tokyo metropolitan area in which the field test results agreed well with the estimated values.

High capacity digital mobile radio system

Abstract: The present invention relates to a mobile radio base station (14) capable of communicating with a large number of mobile stations by implementing space diversity and time-division retransmission techniques in a digital communication system. The digital base station contains a plurality of antenna elements (16 1 -16 M ) and a plurality of retransmission branches (18 1 -18 M ) associated in a one-to-one relationship. When the base station receives a digital communication signal from a mobile station, each antenna element receives the signal with a unique random phase (θ 1 -θ m ) due to the effects of the environment on signal transmission. The signal is then processed through the plurality of retransmission branches, where each branch adapts to compensate for the random phase of the signal received by its associated antenna element. Conversely, when the base station transmits a signal back to the mobile station, each retransmission branch adds the conjugate of its associated random phase to the signal to be transmitted, allowing the environment to "undo" the effect of the conjugate random phase so that the signals transmitted by the plurality of antenna elements will arrive coherently at the mobile station.

Design of a tunnel relay system with a leaky coaxial cable in an 800-MHz band land mobile telephone system

Abstract: System design of a tunnel relay system in an 800-MHz band land mobile telephone system is described. Several dozen RF signals from a base station or many different mobile units in the tunnel are directly amplified in the RF stage, without frequency conversion, by a common amplifier in the relay equipment installed near the tunnel entrance, then radiated into the tunnel through a leaky coaxial cable (LCX) or to the base station by a unidirectional antenna. Repeaters are inserted along the LCX to compensate for transmission loss in RF signal power inside the cable. Amplifying a number of RF signals simultaneously, a common amplifier generates intermodulation products and radiates spurious signals. The required amplifier linearity to suppress the spurious signals is discussed in detail. The combination of LCX and service area in the tunnel is determined according to the amplifier performance, the number of radio channels assigned to the base station, and the radio wave propagation characteristics in the tunnel.

Telephone traffic in mobile radio communication system using dynamic frequency assignments

Abstract: Traffic characteristics of a mobile radio communication system using a dynamic channel assignment scheme which has all channels available at all base stations are derived. In the system with one channel, the traffic characteristics in each zone are exactly obtained. For a multichannel operation, some approximation methods are proposed and some simple examples are also presented.

Traffic broadcasting system

Abstract: The present invention comprises a method of transmitting information from a central ground station to at least one mobile auxiliary ground station via at least one base station. The auxiliary ground stations are located within the transmitting range of at least one base station, and are provided with a receiving device having a control unit and a memory. In accordance with this method, a block of messages cyclically repeated within a time frame is transmitted over a single frequency from the central ground station to the base stations. Each of the messages within the block includes an address code which corresponds to the area code of the region adjacent a corresponding base station. The base stations transmit the block of messages over a single frequency to receiving devices located in the mobile auxiliary ground stations where those messages corresponding to a selected area code are recorded and then played back.

Theoretical studies of a simulcast digital radio paging system using a carrier frequency offset strategy

Abstract: In a multistation simulcast digital radio paging system, each base station transmits the same RF signal simultaneously with the resulting efficient frequency utilization and simplified receiver design. In this system a paging receiver in the overlapping area receives several RF signals transmitted from different base stations. When frequency-shift keying (FSK) is used as a modulation method, experimental test results have already shown that the timing of each RF signal should be synchronized as closely as possible, but that the carrier frequency of each transmitter should be set following a certain offset assignment. The signal transmission performance in a multipath fading environment can then be markedly improved. The cause of this improvement effect is theoretically analyzed. It is clarified that the improvement effect is caused by transforming the probability distribution of time-averaged signal power.

Supervising system for use in radio transmission

Abstract: A phase shift monitoring system is provided for a mobile communication system which includes a central, or base station, one or more sub-base stations, and a plurality of mobile units. Each sub-base station is provided with a detection means which is operable to transmit an alarm signal to the base station when a predetermined tolerable phase shift is exceeded. The base station includes means for readjusting the transmission timing in order to compensate for the detected phase shift, either automatically or by manual control.

Prevention system of incorrect usage of mobile set

Abstract: PURPOSE:To prevent the incorrect usage of a mobile set, by determining the key number corresponding to a mobile set number in advance, and connecting the mobil set to a subscriber via the base station only when this key number is in agreement with the key number stored in the mobile set. CONSTITUTION:When a mobile set is in calling, the key number is transmitted in addition to the calling discrimination signal and mobile set number. The key number is a value determined according to the mobile set number. The base station checks if the mobile set number is registrated or not and the key number is corresponded to the mobile set number or not, and only when YES, the mobile set is connected to the subscriber of fixed station. In case of mobile station having incoming calls, the base station transmits the incoming call indentifying signal, mobile set number to be called and the key corresponding to the number. The mobile set receiving the signal in matching with the mobile set number of itself, further checks if the key number is in agreement, and if YES, it transmits the response signal for connecting operation, and if NO, the response signal is not transmitted and no connection is made.

Information collecting system for mobile station

Abstract: PURPOSE:To reduce the polling loss time by securing the immediate proceeding to the next polling for the base station without waiting for the answer by the individual time slot in case no answer is given at all to the common time slot. CONSTITUTION:Position group signal (a) is transmitted from signal center 2, and mobile station 3 receives and memorizes the position group signal when entering each division. Base station 1 transmits polling signal (b). Station 3 receives signal (b) to decide being called via signal (a) and then transmits the existence confirming signal to station 1 via common time slot SO when an agreement is obtained through the decision. Through this replay, station 1 waits under the reception state and for the time of individual time slots S1-Sn. Then station 3 transmits the signal containing the office number with the corresponding time slot and under the fixed conditions, and station 1 collects sequentially the information of each mobile station for central process 4 and then displays each position. The polling signal is transmitted to the next division with end of the information collection. And no queuing is given if common slot S0 does not receive the answer.

Emergency citizens' band radio system

Abstract: An emergency, CB radio system is disclosed which includes a base station adapter having a wall mounted slide mount for a mobile CB transceiver and an emergency power supply for supplying power to the CB transceiver, the emergency power supply including a rectifier for rectifying line voltage, an internal battery and charger, automatic switching means for switching the transceiver to the internal battery when the line voltage fails, and a jack for patching the transceiver to an external battery when the internal battery is discharged. The base station adapted also includes complete instrumentation for optimizing the performance of the transceiver and its associated antenna. The system further includes remote operating units for operating the transceiver via remotely located microphones and speakers, and a switching center interconnecting the remote operating units and the base station adapter.

Radio equipment for simultaneous transmission and reception

Abstract: PURPOSE:To reduce power consumption without giving unnecessary interruption to a base station, by providing a means which variably controls transmission power continuously in response to a reception input electric field strength at a mobile station. CONSTITUTION:Electromagnetic waves transmitted from a base station (not shown) are received at an antenna 1 of a mobile station and converted into intermediate frequency at a mixing and local oscillator 3 via a common use device 2, amplified and demodulated at an IF amplification demodulator 4 and given to a receiver 5. On the other hand, a part of the intermediate frequency signal obtained at the said mixing and local oscillator 3 is applied to an electric field detector 12, and the circuit 3 generates a DC voltage depending on the received intensity. Further, this DC voltage is applied to a power controller 13 provided between a transmission power amplifier 11 and a modulation/multiplier 9 as a control voltage. Thus, the power transmitted from the antenna 1 to the base station is controlled smaller as the received intensity is greater, and transmission with unnecessary power can not be made to the base station.

Automatic position detection system

Abstract: PURPOSE:To maintain a local route to detect accurately a position with a simple equipment, by causing a moving station to move along a fixed equal propagation time difference hyperbola. CONSTITUTION:Broadcast station BC1 of a medium wave, etc., transmits always sound information with a fixed carrier frequency, and base station FIX receives the radio wave from station BC1 to extract sound information and retransmits it with the carrier wave of VHF or UHF, and moving station P receives radio waves from station BC1 and station FIX to extract respective sound information and compares their phases and returns information of phase difference to station FIX with the carrier wave of VHF or UHF. In station FIX, an equal propagation time difference hyperbola is obtained on a basis of phase information received from station P. This measurement is performed for another broadcast station BC2 also, and an equal propagation time difference hyperbola is obtained similarly, and the geographical position of station P can be obtained as the intersection between two obtained hyperbolas. The obtained position is reported to station P with the radio wave transmitted from station FIX.

Timeedivision multiple mobile communication system

Abstract: PURPOSE:To economize a radio equipment while simplifying circuit control such as reduction in the number of radio equipments of a ground station, removal of a transmitter-combined unit and receiver-combined unit, and simplification the local oscillation of each mobile equipment, by making it possible to transmit many signals by one carrier by time-division multiplexing CONSTITUTION:On a base station, input signals 34-36 are PCM-coded 47-49 and the outputs of them, after being multiplexed 51 in time-dividion mode under control 52, are mixed with conrol time slots from controller 52 and then sent out to cavity resonator 37 The output of receiver 27, on the other hand, is supplied to multiplex separator circuit 56 to exercise control 52 over gate circuits 57-59, and consequently burstlike signals from the mobile equipment are separated by time slots, supplied to time expanders 61-63, an decoded 64-66 to obtain sound output at terminals 31-33 Because of the constitution like this, the number of transmitters and receivers is reduced, transmitter-receivers can be omitted, and the facilities of the base station can remarkably be economized This applies to mobile equipments similarly

Simultaneous transmittinggreceiving radio equipment

Abstract: PURPOSE:To allow an increase in the frequency deviation of a reference frequency oscillator by providing LPF so as to correct transmission and reception frequencies automatically by a received signal. CONSTITUTION:In general, a car radio telephone is receiving signals from a base station without fail and the deviation in frequency sent out from the base station is extremely excellent (e.g., not more than + or -0.5PPM), thereby correcting deviations in transmission and local oscillation frequencies of a mobile radio equipment by a wave transmitted from the base station. Namely, the DC component of a signal from the base station obtained by frequency discriminator 5 is extracted by low- pass filter 15 and applied to reference frequency oscillator 8. When the frequency of oscillator 8 is shifted to generate a difference between the reception frequency and the transmission frequency of the base station, a DC voltage corresponding to the frequency difference is extracted 15 and applied to oscillator 8, which varies in oscillation frequency, so that the reception frequency will agree with the transmission frequency of the base station. In the 400MHz band, when the band of IF amplifier 4 is set to + or -6kHz, the frequency deviation of oscillator 8 is permitted up to + or -15PPM, so that an inexpensive normal crystal oscillator can be used.

Mobile terminal equipment

Abstract: PURPOSE:To make it possible to receive short information without error, by returning information, which is transmitted from the base station, from a mobile terminal. CONSTITUTION:In a mobile terminal, a recived signal is applied to control part 4 to discriminate the whether the signal is directed to the mobile terminal itself or not. When it is decided that the signal is directed to the mobile terminal itself, receiving information is stored in memory 7. Stored contents are returned to the base station at t1 seconds after the start of timer 5 by control part 4. In the mobile terminal, control part 4 waits at t2 seconds after returning of receiving information. In case that information directed to the mobile terminal itself is received again, the same operation is repeated to rewrite contents of memory 7 with receiving information. If transmission information and returned information agree with each other in the base station, no information is transmitted, and incoming display equipment 10 is operated because the mobile terminal itself does not receive information directed to its own station after t2 seconds.

Subscriber*s radio communication system

Abstract: PURPOSE:To simplify the constitution of the slave station and thus to lower the cost for the entire equimpment by providing the oscillator capable of switching the frequency at the base station in case the number of the slave stations is about the same as or larger than that of the base stations. CONSTITUTION:N units of slave stations 401-40N possess transmitter 41, receiver 42, transmitting oscillator 43, receiving oscillator 44 and repeater circuit 45 each. The frequencies of oscillators 43 and 44 differ every slave station. And n units of transmitter/receiver devices 501-50n of the base stations possess base station transmitter 51, base station receiver 52, transmitting oscillator 53, receiving oscillator 54 and hybrid 55 each, and then connected to N units of sibscribers 621- 62N corresponding to the slave stations via switch 61 of control circuit 60. Oscillators 52 and 53 feature the same N units of oscillation frequencies as the slave stations, and are switched sequentially with a fixed interval and the under control of logic control circuit 63 and furthermore so that n units of base station transmitter/receiver devices may synhcronize with different frequencies to wait for the calling given form the slave station. In this way, the constitution of the slave station can be simplified, and the cost can be reduced for the entire subsriber's line call system in the case of N>=n.

Composite communication system using satellite

Abstract: PURPOSE:To make effective use of frequency resources, orbit, and efficient use of satellite and to enable to realize the service of low charge, by the constitution of the communication to various mobile body and to fixed stations through the use of the same satellite and frequency CONSTITUTION:The system constitution is the satellite 1 (irradiating service area through the repetitive use of the frequencies A, B with multispot beam 1a), base station 2 (connecting mobile bodies such as ship, people, and cars with the public network and providing one station for each beam), semifixed/mobile terminal 3 (located at a remote island, having simple antenna such as whip antenna and the output is about 1W), telephone station 4 of the service area of terminal 3, mobile body terminal 5 on land, mobile terminal 6 on ship, and satellite link 7 of the same frequency (eg, 1,500MHz band) and the same satellite channel Further, the same satellite channel is time-shared and this is commonly used for the object of communication including a number of terminal station communications for various mobile communication and for a remote island, which are characterized by the SCPC communication system

Mobile radio terminal unit

Abstract: PURPOSE:To obtain a terminal unit which is portable with a low level of the power consumption at the area which is close to the radio base station or features a comparatively high intensity of the carrier radio electric field. CONSTITUTION:In the case of use in the mobile type, the electric wave received through antenna 6 is amplified at amplifying part 7 via antenna unit 5 to then undergo the necessary process through mobile terminal unit 1. The power is supplied via, for example, storage battery 4 of the automobile and stabilized power source 3. While in the case of the portable use, the compact and light-weight structure featuring the low power consumption is obtained only with portable antenna 9, mobile terminal unit 1, handset 2 and portable battery 8. The possibility for the portable use is decided by displaying the transmission or reception power value commanded from the base station onto terminal unit 1.

Radio telephone system

Abstract: PURPOSE:To improve subscriber service by making it possible to store information about the power break of each subscriber in a base station. CONSTITUTION:Several subordinate stations (subscriber) 21 and 22 are in radio contact with base station 1. Basestation receiver 31 is equipped with power-OFF signal receiver circuit 35 which receives a power-OFF signal from subordinate station 21, power-ON signal receiver 36 which receives a power-ON signal, and registration-number receiver circuit 37 which receives the registration number of subordinate station 21, and outputs of receiver circuits 35-37 are stored in memory 39 via control circuit 38. When one subordinate station attains access to subordinate station 21, power-break information stored in the above-mentioned memory is sent out to a calling-side subscriber with subordinate station 21 OFF in power.

Portable type travelling communication system

Abstract: PURPOSE:To expand a service area by attaching a radio calling function to a portable radio telephone and by calling a party side by setting a radio calling mode in case of the lowering of an electric field level CONSTITUTION:In case that when subscriber's telephone 1 on a base station side calls portable mobile station unit 14, a level detected by field detecting circuit 9 in the mobile station is high, operation mode circuit 10 controls mode switching circuit 11 automatically to connect transmitter-receiver 8 to telephone 12, thereby setting a telephone circuit to telephone 1 When the detected level of circuit 9 is intermediate, circuits 10 and 11 sets a radio calling mode to connect transmitter- receiver 8 to radio calling circuit 13, thereby making an answer from unit 14 to the base station automatically Radio calling control circuit 5 on the base station side requests originating subscriber's exchange 2 to send an originating number and then sends the originating number to unit 14 via mobile communication exchange 3 Receiving this, unit 14 talks over to the calling subscriber via a public station, etc When the detected level of circuit 9 is low, the system waits for the reception state to recover

Travelling communication system

Abstract: PURPOSE:To make duplex transmission possible by using a general subscriber's telephone set as it is between a fixed station side and mobile station side by transmitting information by a push-button dial while receiving it by sound of the telephone. CONSTITUTION:At a fixed station, radio base station 4 is called via telephone exchange 3 through the dialing of push-button dial telephone set 1. At base station 4, information stored previously in a memory is read and converted by a sound synthesizing circuit into sound to send words, such as [Please input your number.], to telephone set 1, from which a calling-subscriber's number is sent by a push-button dial signal and then stored. Next, information on [Please input the party's number.], for example, is read from the memory and converted into sound, which is sent to telephone set 1. Similarly, the same operation is repeated and when the calling subscriber sends a signal of transmission OK to base station 4, base station 4 sends the information stored in the memory to mobile station 5.

Underrcalling display system for radio communication system

Abstract: PURPOSE:To avoid the double calling from other terminal stations by carrying out the transmission of the under-calling signal from the base station while the under- calling signal is being transmitted to the wire terminal unit at the base station by the calling from the terminal station and then informing the under-calling state the wire terminal unit to the base station. CONSTITUTION:When wire terminal units TEL1-TELn are connected to exchange EX to carry out the radio communication between base station MS and fixed terminal station TS1 or TS2, station MS applies the call signal to signal transmitter SS2 with reception of the call of station TS1 or TS2 to units TEL1-TELn and then transmits the under-calling signal Sb via transmitter/receiver TRX. Then station TS1 or TS2 which received signal Sb and transmitted the call signal confirms that the call signals have been transmitted to units TEL1-TELn to carry out the answering operation to the partner. At the same time, other terminal station TS1 or TS2 knows that station MS is transmitting the call signal and then decides that the self-calling is impossible.

Circuit test system for mobile communication system

Abstract: PURPOSE:To simplify the constitution of a mobile station by providing a testing mobile station with a transmitter-receiver, test-signal detector and sending-back circuit only and then by performing operations, which should be done by the mobile station, by an artificial mobile station. CONSTITUTION:On receiving a test signal by the receiver of channel CH1, testing mobile station TS in communication zone Z1 sends back the received signal, as it is, by the sending-back circuit. Then, it is inputted to artificial mobile station DS via base station MS1 and switching connection states of other than channel CH1 of base station MS1 are reset by the detection output. Consequently, test board TB and testing mobile station TS are connected together by way of base station MS1, artificial mobile station DS and exchange EX. Then, artificial mobile station DS detects the arrival of a signal from the side of base station MS1 to base station MS1 via mobile station TS. Therefore, the constitution of the testing mobile station is simplified, so that miniaturization and improvement of mobility will be realized.

Mobile message communication method

Abstract: PURPOSE:To utilize a frequency effectively by using two frequencies, at least, to transmit messages between the base station and a mobile terminal. CONSTITUTION:Message 3 is transmitted to a called terminal by transmission frequency f1 during calling period T1 from the base station, and primary response signal 4 is transmitted from the called terminal by transmission frequency f2, and therefore, the base station confirms dependently upon this primary response signal 4 that message 3 has been transmitted to the mobile terminal. Calling permission signal 5 is transmitted from the base station by transmission frequency f1 during calling permission period T2 of the mobile terminal, and response message 10 is transmitted from the called terminal to the base station. Secondary response permission signal 11 is transmitted from the base station to the calling terminal during secondary response period T3, and secondary response message 14 is transmitted from the calling terminal to the base station.

Check system for radio line

Abstract: PURPOSE:To enable to check the propriety of lines, by using the timing circuit, count circuit and AND gate circuit, in performing transmission and reception of digital code through radio links for the base station and a plurality of mobile stations or a plurality of mobile stations themselves. CONSTITUTION:In the base station, the response signal is converted into binary digital code via the reception antenna AR, receiver 14, and demodulator 13. Further, this code feeds the control signal representing the good decision only when all the 7-bit of binary code is in agreement and detected the same as the decision at the synchronizing signal decision section for each mobile station at the decision signal detection section 12, to the AND gate circuit 11. Next, the number of mobile station expected for the response at the count circuit 3 during count operation with the clock of the timing circuit 1 from the start of line check is called for, and the control signal is rewritten at the ROM circuit in the AND gate circuit 11. Thus, the propriety of decision is outputted from the reception terminal 10 such as the printer of printing telegraph machine.

Mobile terminal equipment for mobile message communication

Abstract: PURPOSE:To transmit and receive messages between a mobile terminal equipment and the base station under the control of the base station, by providing the receiving display function and the transmission function of messages. CONSTITUTION:In a mobile terminal station, a response signal is transmitted to display a message on display part 8 when receiving the message from the base station. Control part 5 opens gate circuit 13a or 13b to transmit a transmission message or a response message according to the calling permission or response permission signal from the base station. Consequently, not only simple calling of the mobile terminal station but also transmission and receiving of simple messages are possible. The transmission timing is determined according to the control from the base station, and transmission and receiving frequencies are different, so that the radio line can be utilized efficiently.