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Showing papers on "Base station published in 1984"


Journal ArticleDOI
Jack Harriman Winters1
TL;DR: Analytical and computer simulation techniques are used to determine the performance of optimum combining when the received desired and interfering signals are subject to Rayleigh fading, and results show that optimum combining is significantly better than maximal ratio combining even when the number of interferers is greater than thenumber of antennas.
Abstract: This paper studies optimum signal combining for space diversity reception in cellular mobile radio systems. With optimum combining, the signals received by the antennas are weighted and combined to maximize the output signal-to-interference-plus-noise ratio. Thus, with cochannel interference, space diversity is used not only to combat Rayleigh fading of the desired signal (as with maximal ratio combining) but also to reduce the power of interfering signals at the receiver. We use analytical and computer simulation techniques to determine the performance of optimum combining when the received desired and interfering signals are subject to Rayleigh fading. Results show that optimum combining is significantly better than maximal ratio combining even when the number of interferers is greater than the number of antennas. Results for typical cellular mobile radio systems show that optimum combining increases the output signalto-interference ratio at the receiver by several decibels. Thus, systems can require fewer base station antennas and/or achieve increased channel capacity through greater frequency reuse. We also describe techniques for implementing optimum combining with least mean square (LMS) adaptive arrays.

942 citations


Journal ArticleDOI
Jack Harriman Winters1
TL;DR: In this paper, the authors used analytical and computer simulation techniques to determine the performance of optimum combining when the received desired and interfering signals are subject to Rayleigh fading, and they showed that optimum combining is significantly better than maximal ratio combining even when the number of interferers is greater than number of antennas.
Abstract: This paper studies optimum signal combining for space diversity reception in cellular mobile radio systems. With optimum combining, the signals received by the antennas are weighted and combined to maximize the output signal-to-interference-plus-noise ratio. Thus, with cochannel interference, space diversity is used not only to combat Rayleigh fading of the desired signal (as with maximal ratio combining) but also to reduce the power of interfering signals at the receiver. We use analytical and computer simulation techniques to determine the performance of optimum combining when the received desired and interfering signals are subject to Rayleigh fading. Results show that optimum combining is significantly better than maximal ratio combining even when the number of interferers is greater than the number of antennas. Results for typical cellular mobile radio systems show that optimum combining increases the output signal-to-interference ratio at the receiver by several decibels. Thus, systems can require fewer base station antennas and/or achieve increased channel capacity through greater frequency reuse. We also describe techniques for implementing optimum combining with least mean square (LMS) adaptive arrays.

621 citations


Patent
11 May 1984
TL;DR: In this paper, a telecommunication control complex, including a mobile telecommunication controller (101) and a cell site controllers (164), controls the radio connections between these communication links and the mobile units.
Abstract: A method and apparatus for controlling a cellular mobile telecommunication system. A switch (153) and a telecommunication control complex (101, 164, 163, 142, 144, 143, 145) cooperate to set up connection between a telecommunication network, such as the common carrier public telephone network, and a plurality of mobile units (165). The switch sets up connections between trunks to the telephone network (157, 158) and communication links (149, 150, 160, 161) connected to the cell sites (I, N) of the mobile telecommunication system. The telecommunication control complex, including a mobile telecommunication controller (101) and a cell site controllers (164), controls the radio connections between these communication links and the mobile units.

56 citations


Patent
05 Apr 1984
TL;DR: In this article, a real-time geophysical survey system consisting of a base station, one or more data acquisition vehicles, and fixed reference stations is presented, where the base station is provided with a positioning system, suitable survey instrumentation, a computer, and radio communication equipment.
Abstract: A real time geophysical survey system and method. The system comprises a base station, one or more data acquisition vehicles, and one or more fixed reference stations. The base station is provided with a positioning system, suitable survey instrumentation, a computer, and radio communication equipment. The data acquistion vehicles are each provided with a positioning transponder, a positioning display, suitable survey instrumentation, and radio communication equipment. During a survey, by periodically polling each vehicle's positioning transponder, the base station positioning system tracks the position of each vehicle with respect to both the base station and the fixed reference stations. Data regarding each vehicle's position are then provided to the base station computer, and the base station transmits signals to the positioning display aboard each vehicle so as to guide the vehicle along a preselected survey pattern. As the survey progresses, data respresenting geophysical measurements taken by instrumentation carried by each vehicle are periodically transmitted to the base station computer. Such data are then correlated in real time with the position of the vehicle and with data collected at the base site, and then output for evaluation by the base station computer.

55 citations


Journal ArticleDOI
TL;DR: Signal-to-interference ratio statistics for mobile telephony systems with hexagonal coverage areas, multiple interferers, and three-corner base stations are investigated and improvement is on the order of 11 dB over a baseline arrangement which employs centrally located omnibase stations without macrodiversity.
Abstract: Signal-to-interference ratio statistics for mobile telephony systems with hexagonal coverage areas, multiple interferers, and threecorner base stations are investigated. Corner base stations simultaneously reduce total interference (because of antenna directivity) and provide macrodiversity against shadow fading. Our results indicate that for 3 or 7 channel sets, with 2 tiers of interferers and typical system parameters (propagation exponent of 3.7 and lognormal spread of 8 dB), the improvement is on the order of 11 dB over a baseline arrangement which employs centrally located omnibase stations without macrodiversity. Additional considerations of blocking probabilities and average voice activity indicate possible further improvements.

41 citations


Journal ArticleDOI
K. Kammerlander1
TL;DR: It is shown that distance measurement is the most reliable means of detecting cell boundaries in public land mobile networks and new approaches for system control channels lead to synchronous operation of base stations.
Abstract: The paper presents a survey of a new approach to advanced system solutions for mobile radio telephone systems. It is shown that, by the combination of both radio techniques and microprocessor data capabilities, improved means are available for controlling the specific multiple propagation and interference influences within the mobile radio environment. The aim of the system structure is to achieve the best possible frequency channel utilization, system availability, and cost benefits for deployment and users if traffic demand grows. The paper shows the different types of switching functions in public land mobile networks. Problems, as caused purely by radio conditions, are controlled within a defined radio exchange function, allowing the optimization of individual cell parameters. It is shown that distance measurement is the most reliable means of detecting cell boundaries. New approaches for system control channels lead to synchronous operation of base stations. The system operates with off-air call setup and queueing to improve channel utilization. Full national and international roaming capabilities are provided. During all calls, continuous digital link control is maintained to allow the radio exchange function in call condition. This new approach leads to different types of handoff to suit specific situations. Speech scrambling provides subscriber privacy.

27 citations


Journal ArticleDOI
TL;DR: In this article, the authors investigated the performance of three-corner base stations with hexagonal coverage areas, multiple interferers, and three-CORNER base stations simultaneously reducing total interference and providing macrodiversity against shadow fading.
Abstract: Signal-to-interference ratio statistics for mobile telephony systems with hexagonal coverage areas, multiple interferers, and three-corner base stations are investigated. Corner base stations simultaneously reduce total interference (because of antenna directivity) and provide macrodiversity against shadow fading. Our results indicate that for 3 or 7 channel sets, with 2 tiers of interferers and typical system parameters (propagation exponent of 3.7 and lognormal spread of 8 dB), the improvement is on the order of 11 dB over a baseline arrangement which employs centrally located omnibase stations without macrodiversity. Additional considerations of blocking probabilities and average voice activity indicate possible further improvements.

21 citations


Patent
Hiromi Orikasa1
19 Sep 1984
TL;DR: In this article, the line concentrator of a mobile radiotelephone system is used to send a false calling tone signal from a tone signal delivery circuit to an end station for a predetermined short period of time.
Abstract: A base station (coast station) of such a radiotelephone system as a maritime mobile radiotelephone system is connected to a telephone exchange of a public telecommunication network. A ringing signal from a subscriber's station of the telecommunication network which is connected to the exchange is transmitted to an end station (ship station) of the radiotelephone system by way of the line concentrator and a radio section between the base and end stations. When a false calling tone signal is sent from a tone signal delivery circuit included in the line concentrator to an end station for a predetermined short period of time upon completion of a connection between the exchange and the end station, with no regard to a ringing signal from the exchange, a subscriber's telephone at the end station produces a calling tone. Thereafter, the line concentrator delivers a calling tone signal in synchronism with a ringing signal from the exchange. The telephone at the terminal station, therefore, produces a tone immediately after a connection has been completed, so that the subscriber at the end station is prevented from off-hooking during an interruption time of a calling tone to cause collision of receipt of a call and origination of a call.

19 citations


Proceedings ArticleDOI
21 May 1984
TL;DR: The circuit configuration and principal techniques to reduce volume, weight and power consumption for detachable mobile radio units and the results of field tests carried out in the existing 800 MHz land mobile telephone system are presented.
Abstract: Detachable mobile radio units, which can be used not only in a car but also as a portable radio unit outside the car, have been developed by the Electrical Communication Laboratories, NTT, for use in the existing 800 MHz mobile radio telephone system in Japan. This paper describes the circuit configuration and principal techniques to reduce volume, weight and power consumption for these detachable mobile radio units. The results of field tests carried out in the existing 800 MHz land mobile telephone system to evaluate effective antenna gain and practical service coverage are also presented.

18 citations


Journal ArticleDOI
TL;DR: An analysis of traffic parameters for different types of users of land mobile radio (LMR) communications channels is presented, and the effects of grouping two users on the same channel are discussed from both channel allocation and grade of service points of view.
Abstract: An analysis of traffic parameters for different types of users of land mobile radio (LMR) communications channels is presented. Based on audio monitoring of voice traffic, this analysis provides valuable information concerning efficiency of channel utilization by users; such information corroborates results already obtained through RF carrier monitoring. In addition, a user classification strategy, based on their message characteristics, is proposed and different procedures are suggested for estimating user message length when only base station information is available. Finally, the effects of grouping two users on the same channel are discussed from both channel allocation and grade of service points of view.

18 citations


Patent
02 Apr 1984
TL;DR: In this article, a communication control circuit including a monitor circuit for receiving transmissions of a first and second frequency from a base radio station to other radio stations and measuring several time intervals is presented.
Abstract: A communications control circuit including a monitor circuit for receiving transmissions of a first and second frequency from a base radio station to other radio stations and measuring several time intervals, each time interval being the time from the end of a first frequency transmission to the end of a second frequency transmission The two frequency transmissions are a portion of the signal protocol required by the base radio station to establish a communications link between a radio station and a base radio station The control circuit further includes logic circuitry for computing an estimated delay time used in delaying the transmission of an identification code to the base station to establish the communication link after the end of the first frequency transmission The estimated delay time is computed from monitoring other successful radio station protocol exchanges with the base station and measuring similar delay times and adjusting the delay time iteratively based upon the monitored delay times and any deviation between these monitored delay times and the estimated delay time

Patent
13 Aug 1984
TL;DR: In this article, the authors propose to utilize a radio channel effectively by providing a mobile equipment with a data terminal and a packet device, and sending packeted data out of plural mobile equipments through the same control signal circuit and talking circuit in common.
Abstract: PURPOSE:To utilize a radio channel effectively by providing a mobile equipment with a data terminal and a packet device, and sending packeted data out of plural mobile equipments through the same control signal circuit and talking circuit in common. CONSTITUTION:Data inputted from a data terminal 2 is packeted by a packet device 3 and this packet is transmitted from a mobile equipment to a mobile telephone exchange 7 through a base station 4 by using the control signal circuit or talking circuit. The packet received by the station 7 is converted into constitution matching with a packet network and transmitted to a data terminal or center 10 connected to the network through packet exchanges 8 and 9. When the packeted data is transmitted from the data terminal or center 10 connected to the packet network, this packet is converted by the station 7 into packet constitution which is receivable by the mobile equipment, transmitted from a base station 6 to the mobile equipment, and then supplied to the data terminal 2 through the packet device 3.

Proceedings Article
01 Jan 1984
TL;DR: In this paper, an analysis of traffic parameters for different types of users of land mobile radio (LMR) communications channels is presented based on audio monitoring of voice traffic, which provides valuable information concerning efficiency of channel utilization by users; such information corroborates results obtained through RF carrier monitoring.
Abstract: An analysis of traffic parameters for different types of users of land mobile radio (LMR) communications channels is presented. Based on audio monitoring of voice traffic, this analysis provides valuable information concerning efficiency of channel utilization by users; such information corroborates results already obtained through RF carrier monitoring. In addition, a user classification strategy, based on their message characteristics, is proposed and different procedures are suggested for estimating user message length when only base station information is available. Finally, the effects of grouping two users on the same channel are discussed from both channel allocation and grade of service points of view.

Journal ArticleDOI
TL;DR: The SERIES technique makes it possible to perform simultaneous pseudo ranging to multiple NAVSTAR-GPS satellites without knowledge of the codes usually required to make use of these satellites.
Abstract: A technique known as SERIES (Satellite Emission Range Inferred Earth Surveying), is a method by which radio signals from artificial satellites already in earth orbit can be exploited for positioning and navigation. The existing satellites of choice are those of the Global Positioning System (GPS). The SERIES technique makes it possible to perform simultaneous pseudo ranging to multiple NAVSTAR-GPS satellites without knowledge of the codes usually required to make use of these satellites. The accuracy achievable with the SERIES system in a dynamic environment is at the meter level when operated in a differential mode with a single base station which may be several hundred km away. To achieve real time operation, it is necessary to cross-link the base station receiver output to the dynamic vessel which determines its position and velocity relative to the geodetic position of the base. The demands upon the cross-link communications are very modest at an average rate of only one byte per second. Since the technique has no requirement for a knowledge of the GPS codes, it is possible to use both of the P-code channels at L1 and L2 to accomplish the ionospheric calibrations which are essential for achieving one meter accuracy over distances of several hundred kilometers. The conditions under which the SERIES technique will function are compatible with all civilian needs but are not useful in military operations because of electronics-countermeasures already developed. By the use of a pair of receivers on a single vessel, it is possible to configure an angular orientation measurement system using the NAVSTAR satellites as the frame of reference and with an accuracy of 0.1 degree or better without any moving parts.

Patent
11 Sep 1984
TL;DR: In this paper, the authors propose to decide exactly a level and to shorten a connection control time by assigning a different time slot to each base station and sending a control signal based on a synchronizing signal.
Abstract: PURPOSE:To decide exactly a level, and to shorten a connection control time by assigning a different time slot to each base station and sending a control signal CONSTITUTION:In case when communication between a mobile station and a base station 3 is set in plural radio zones 2 by using a common control channel, each base station determined the position of each transmitting time slot so that it is not overlapped with each station, basing on a synchronizing signal 6 When a signal is transmitted by a timing which is not overlapped with every base station, the mobile station measures a demodulating level at every time slot by which each intrinsic control signal is transmitted with regard to each base station 3, basing on a signal 6 Subsequently, a time slot by which the maximum demodulating level appears is decided As a result, the base station to which a communication should be executed exactly is decided, and also its decision is executed in advance, therefore, the connection control time is shortened

Patent
26 Oct 1984
TL;DR: In this article, a method of carrying out a radio propagation survey in which a site may be an industrial site, such as a power station, or an urban area, is divided into a plurality of elemental areas of a size greater than twenty times the wavelength of the carrier frequency of a test signal transmitted by a base station is presented.
Abstract: A method of carrying out a radio propagation survey in which a site (10) FIG 1 which may be an industrial site, such as a power station, or an urban area, is divided into a plurality of elemental areas (12) of a size greater than twenty times the wavelength of the carrier frequency of a test signal transmitted by a base station (14). An operator equipped with a receiver (18) having a communications probability indicator (22) (Figures 2 and 3 (not shown)) proceeds from one elemental area to the next, either on foot or in a vehicle, monitoring a particular characteristic of the transmitted signal and the number of occurrences of that characteristic within a predetermined sampling period in each elemental area, thereby determining the quality of reception of that characteristic. This characteristic may be either the carrier strength or SINAD (the ratio of the [signal plus noise plus distortion] to [noise plus distortion]). In order to conduct a survey for two-way radio communication the power output of the base station is adjusted to equal that of the weakest transmitter to be used in the radio system.

Patent
28 May 1984
TL;DR: In this article, the number of channels between the repeater stations 3a-3d and the base station BS2 is set up smaller than that between the BS and the local station to simplify the constitution of a local office.
Abstract: PURPOSE:To simplify the constitution of a local office, to assign and control channels on the base station side and to utilize efficiently the titled system by using a repeater station having a time division radio line and setting up the number of channels between the base station and the repeater station smaller than that between the repeater station and the local station. CONSTITUTION:Balanched repeater stations 3a-3d for the base station BS2 connected by a PCM line are formed in a switchboard LS1 for a public telephone network and plural local stations 4a1-4d12 corresponding to respective repeater stations 3a-3d are formed. Subscribers 5a11-5d122 are connected to the respective local stations 4a1-4d12 to constitute a multi-direction time division radio communication system. Transmission/reception parts 11, 12 are controlled by a channel separation part 14 in the respective repeater stations 3a-3d. An insertion control part 17 is controlled by a separation control part 15 and a synchronization detecting part 16 and a channel insertion part 16 is controlled by the control part 17. The number of channels between the repeater stations 3a-3d is set up smaller than that between the base station and the repeater stations 3a- 3d to simplify the constitution of the respective local stations 4a1-4d12.

Patent
21 Mar 1984
TL;DR: In this paper, the authors proposed a data communication protocol for data transmission between mobile stations and a base station, by receiving a radio wave at the base station from the mobile station, and demodulating the information at the BS in correlating with a pseudo noise code which is equal to that of a mobile station.
Abstract: PURPOSE:To perform the data communication for data transmission between plural mobile stations and a base station, by receiving a radio wave at the base station from the mobile station, and demodulating the information at the base station in correlating with a pseudo noise code which is equal to that of the mobile station CONSTITUTION:A radio wave (frequency fi) is received at an antenna 4 from a mobile station This received radio wave is supplied to a frequency converter 7 through a circulator 17, a BPF5 and an amplifier 6 to receive a conversion of frequency with the signal of a local oscillator 8 (frequency f1) A demodulator 3 demodulates the information sent from a mobile station The output of the oscillator 8 is also supplied to another frequency converter 14 to receive a conversion of frequency with the signal of an oscillator 15 (frequency f1-fi+ mfc1 or f1-fi-mfc1) and changed into a signal having a frequency component of fi-mfc1 or fi+mfc1 This signal is transmitted via a BPF16 which transmits a signal having a frequency component of fi-mfc1 or fi+mfc1 and a circulator 17 and through the antenna 4

Patent
03 Sep 1984
TL;DR: In this article, the same service is offered to subscribers in both master and slave areas by selecting automatically a usable channel among channels used by a base station so as to attain transmission/receiving to the base station and attaining the transmission and receiving with a terminal station on a different channel in the slave area.
Abstract: PURPOSE:To offer the same service to subscribers in both master and slave areas by selecting automatically a usable channel among channels used by a base station so as to attain transmission/receiving to the base station and attaining the transmission/receiving with a terminal station on a different channel in the slave area. CONSTITUTION:The base station 1 has channel frequencies F1-Fn for transmission and channel frequencies F'1-F'n for receiving. A radio relay device 5 has the channel frequencies F'1-F'n for transmission with the base station 1 and the channel frequencies F1-Fn for receiving, and channel frequencies f1-fm for receiving and channel frequencies f'1-f'm with a terminal station 6 of a slave area B, and detects and relays a signal from the base station 1 to the slave area B and a signal from the terminal station 6 to the base station 1. A transmission output of the relay device 5 to the slave area B is not detoured to the receiver input under the condition of the channel frequencies of F1-Fn

Proceedings ArticleDOI
21 May 1984
TL;DR: A statistical method for determining the coverage range of transmitters in a mobile system, both in the absence and presence of co-channel interference is developed.
Abstract: Cellular radio systems are a sophisticated application of trunked mobile radio technology in which the range of the base station transmitters are interference limited from co-channel reuse of frequencies instead of being noise limited. Accordingly, effective design of these systems requires an understanding of co-channel interference and its impact on coverage range as the cellular system designer must "manage" interference rather than avoid it. This paper develops a statistical method for determining the coverage range of transmitters in a mobile system, both in the absence and presence of co-channel interference. Two basic methods are examined and compared for defining and determining the reliability of reception in cellular systems--namely, the probability of reception along a contour boundary and the average probability of reception within a contour. The basic 12-cell and 7-cell omnidirectional systems are analyzed under both methods. Examples are presented that enable a quantitative comparison of these two basic methods and associated design criteria.

Patent
27 Mar 1984
TL;DR: In this article, a channel switching request signal is generated by a man's decision that a radio system is cross talked or a lot of noises exist, with respect to a quality of a call state and a will for switching a channel is generated.
Abstract: PURPOSE:To execute switching of a call channel by a will of a subscriber of a terminal equipment side, who feels a noise, etc., by providing a control signal (manual channel switching request signal) between a channel control device and the terminal equipment. CONSTITUTION:For instance, a terminal equipment 21 is in a call state with other subscriber 29 by channels 24, 26 and 27 passing through a transmitter (TX) 22 and a receiver (RX) 23 of a radio base station, and a channel control device 25. When it is felt by a man's decision that a radio system is cross talked or a lot of noises exist, with respect to a quality of a call state and a will for switching a channel is generated, in the terminal equipment side, an operation of the terminal equipment is converted to a channel switching request signal 28 by a channel switching request signal sending-out function by operating a channel switching button, and it is send out to the channel control device 25 through the base station. When this signal is received, the channel control device 25 side executes the same processing as the channel switching detected by the receiver 23 of the radio base station. In this way, a drop of a call quality which cannot be detected automatically can be recovered.

Patent
17 Oct 1984
TL;DR: In this paper, the authors proposed to apply optimum car allocation even when traffic regulation such as one-way traffic exist by adding running direction information of a mobile station to information transmitted from a mobile stations to a base station in a taxi allocation system using a radio system.
Abstract: PURPOSE: To apply optimum car allocation even when traffic regulation such as one-way traffic exist by adding running direction information of a mobile station to information transmitted from a mobile station to a base station in a taxi allocation system using a radio system. CONSTITUTION: A direction detecting processor 4 detecting the progressing direction of an automobile is provided to a mobile station side and the detected data is inputted to signal processor 2. The processor 2 transmits a mode signal representing a corresponding taxi as to whether it is an idle car or an occupied car, a position signal representing the running position, a running time and direction information obtained by the processor 4 to a base station via the radio equipment 3. The base station decides a mobile station reaching fastest a position of a customer for the taxi based on the said various kinds of information transmitted from the mobile station and informs the information to the said mobile station. COPYRIGHT: (C)1986,JPO&Japio

Patent
13 Apr 1984
TL;DR: In this article, the authors propose to always have communication with correct time information and without troublesome manual correction, by transmitting an accurate time information signal from a base station to receive it by a mobile radio device and correcting automatically an internal timer.
Abstract: PURPOSE:To always have communication with correct time information and without troublesome manual correction, by transmitting an accurate time information signal from a base station to receive it by a mobile radio device and correcting automatically an internal timer. CONSTITUTION:A correction is carried out with a correct standard time at each time decided by a standard timer part 8 and under the control of a control part 6 of a base station, and a signal showing the present time point is applied to a signal converting part 7. The part 7 converts the signal into a format to be sent to a mobile radio device and undergoes the higher harmonic modulation at a transmitting part 4 to be transmitted to the mobile radio device through an antenna 1. This signal is received at a signal receiving part 11 via an antenna 9 of the mobile radio device and then applied to a control part 14 and a time information detecting part 15. A signal is applied to a timer part 16 to correct the count value when the time information given from the base station is detected at the part 15. Thus the count value of the part 16 is automatically corrected, and this corrected value is displayed at a time display part 17 under the control of the part 14. Thus it is possible to perform communication between a base station and a mobile radio device at a correct time point at all times.


Patent
14 Feb 1984
TL;DR: In this article, a radio-telephone communications system with a plurality of selectable base stations for relaying speech and data radio signals to mobile units is controlled by channel monitors 3 and a master controller 4.
Abstract: A radio-telephone communications system with a plurality of selectable base stations TR for relaying speech and data radio signals to mobile units is controlled by channel monitors 3 and a master controller 4. The monitors 3 are caused to store digital data describing the quality of audio signals provided by the associated base stations TR in terms of peak and mean values of the amplitude probability density histogram and the master controller 4 interrogates the monitors 3 to select the base stations TR having the best- quality received incoming signal.

Patent
20 Jan 1984
TL;DR: In this article, the authors proposed to prevent ineffective retention of a radio channel by allowing a base station to inform a busy signal during the use of channel and a collision signal at collision, to a radio equipment.
Abstract: PURPOSE: To prevent ineffective retention of a radio channel by allowing a base station to inform a busy signal during the use of channel and a collision signal at collision, to a radio equipment. CONSTITUTION: When a mobile set 21 starts communication, a communication request signal with a preamble at the head is transmitted to a base station 1. When the base station 1 detects the preamble, the station uses an outgoing channel and transmits a busy signal to all mobile sets 21, 22. In receiving the busy signal, the mobile set 21 during communication continues the communication and the other mobile set 22 transmitting communication request from now withdraws the transmission. When plural mobile sets 21, 22 transmit the communication request at the same time, the base station 1 detecting it by means of pattern deformation of the preamble or the like transmits the collision signal to the outgoing channel. The mobile sets 21, 22 receiving the collision signal stop immediately transmission, and send out the communication request signal again after back-off is executed. COPYRIGHT: (C)1985,JPO&Japio

Patent
31 Aug 1984
TL;DR: In this article, the authors proposed to obtain a wide service area for a mobile station by setting automatically the direction of a directional antenna at a base station by a location designation signal from a terminal station or the mobile station to use effectively the directional antenna.
Abstract: PURPOSE:To obtain a wide service area for a mobile station by setting automatically the direction of a directional antenna at a base station by a location designation signal from a terminal station or the mobile station to use effectively the directional antenna. CONSTITUTION:The location designating signal from the terminal station or the mobile station is transmitted on a radio wave, the base station receives this radio wave by a non-directional antenna 1, and the signal is demodulated by a radio equipment 4 through an antenna switching device 3, and its demodulated output is received by an antenna direction controller 5. The kind of the signal from the terminal station or the mobile station is discriminated by the antenna direction controller storing the kinds, the antenna switching device 3 is switched to a directional antenna 2, an antenna turn table 6 is operated so as to set automatically the directivity of the directional antenna 2 to a direction in which the terminal station or the mobile station exists. When the setting is finished, a call start signal is transmitted from the directional antenna 2 via the antenna direction controller 5 and the radio equipment 4.

Patent
23 Aug 1984
TL;DR: In this paper, the authors proposed to decrease the number of receivers and to attain economization by connecting receivers more than directional antennas differing in direction and speech channels to the antennas and channels through switching according to a communication congestion state and a reception level.
Abstract: PURPOSE:To decrease the number of receivers and to attain economization by connecting receivers more than directional antennas differing in direction and speech channels to the antennas and channels through switching according to a communication congestion state and a reception level. CONSTITUTION:The directional antennas 10a-10f installed on the base station of a mobile radio system at angle intervals of 60 deg. covers the whole communication area. The receivers which are more than the antennas and speech channels CH and less than twice as many as the CHs and shared among the respective CHs are connected to the antennas and transmission gates 40a-40l which are installed corresponding to the speech CHs and perform the instantaneous diversity reception of each CH optionally through connection switching circuits 30 and 50. A control circuit 60 monitors reception levels 22a-22n of the respective receivers 20a-20n to determine whether a communication with a mobile station is performed at the mean level of two receivers according to a communication congestion state and reception levels or by the instantaneous diversity reception of one receiver, and outputs switching control signals CA and CC to the circuits 30 and 50 and a frequency switching signal CF to a receiver.

Patent
Koichi Nagata1, Izumi Nishimura1
14 Feb 1984
TL;DR: In this article, the authors rationalize a charging job by transmitting a signal to a designated opposite station only while a code representing individual/group/simultaneous transmission in response to the content of a telegraphic message from a base station to plural reception stations and counting the number of times of transmission at each opposite station.
Abstract: PURPOSE: To rationalize a charging job by transmitting a signal to a designated opposite station only while a code representing individual/group/simultaneous transmission in response to the content of a telegraphic message from a base station to plural reception stations and counting the number of times of transmission at each opposite station CONSTITUTION: A radio base station (a) transmits a radio wave formed by a telephone set 1, an exchange 2, a contro section 3, a modulator 4 and a transmitter 5 from an antenna 6 The control section 3 adds an identification code depending on whether a transmission opposite station is a single station, a group or simulatneous transmission, transmits a telegraphic message only to the designated opposite station and also counts and stores the number of times of transmission by each reception station Each reception station (b) demodulates (9) a received radio wave, decodes (10) it, compares it with the content of a memory of a ROM11 and activates a tone generator 14 when the signal is addressed to the own station, a speaker 15 is energized and the telegraphic message is displayed on a display device 13 Moreover, the number of times of decoder reception is recorded Thus, the reception of an unnecessary signal is excluded and the accurate charging is calculated COPYRIGHT: (C)1985,JPO&Japio

DOI
01 Jul 1984
TL;DR: In this article, a cellular land-mobile radio system with combined mobile telephone and dispatch services is considered, where two flow control levels for dispatch users are introduced to preserve the quality of mobile telephone service.
Abstract: In this paper a cellular land-mobile radio system with combined mobile telephone and dispatch services is considered. A hybrid scheme for channel assignment is considered. Two flow control levels for dispatch users are introduced to preserve the quality of mobile telephone service. Results are obtained by computer simulation of the system.