Showing papers on "Base station published in 1983"

Power control for a spread spectrum cellular mobile radio system

Abstract: In two earlier papers (ICC'80 [3] and GLOBECOM'82 [6]) two power control schemes for spread spectrum cellular land mobile radio have been described, one for the upstream (mobile to base) link and one for the downstream link Here we compare the power control problem for the upstream and the downstream links and show that using simple algebra we can equalize the signal-to-interference ratio for each mobile in a given cell in both links and thereby increase the capacity by 30 to 100% compared with a system with no power control We also show that the SIR values can be equalized system-wide for both link directions by means of a nontrivial eigenvalue problem, which results in a further capacity improvement of 10 to 15% Denial statistics are also presented

Method and apparatus for assigning duplex radio channels and scanning duplex radio channels assigned to mobile and portable radiotelephones in a cellular radiotelephone communications system

Abstract: A unique method and apparatus for efficiently assigning duplex radio channels and scanning duplex radio channels assigned to mobile and portable radiotelephones in a cellular communications system (Fig 1) Each cell (10, 20, 30) includes a base station radio (111, 121, 131) having a signalling channel and a plurality of voice channels, and a base site controller (112, 122, 132) adapted to utilize the methods embodying the present invention for controlling communications paths to mobile and portable radiotelephones The base station radios (Fig 2) include a signalling transceiver (250) operable on the signalling channel, a plurality of voice transceivers (220, 230) each operable on a voice channel, and a scanning receiver (240) for sampling the signal strength of active radiotelephones Transmitters of the signalling transceivers (250) and voice transceivers (220, 230) are combined (210) and coupled to an omnidirectional antenna (212); and the receivers of the signalling transceiver (250), voice transceivers (220, 230) and scanning receiver (240) are coupable to one or more of six sector antennas (214) In practicing the methods of the present invention, the microprocessor (358) controlled base site controller maintains high quality communications paths to mobile and portable radiotelephones by periodically monitoring their signal strength and when signal strength degradations are detected, either changing the base station sector antennas (214) coupled to voice transceivers (220, 230), increasing or decreasing radiotelephone power output, or handing radiotelephones off to another cell

Switched diversity with feedback for DPSK mobile radio systems

Abstract: Switched diversity with feedback for differential phase shift keying (DPSK) mobile radio is discussed. The technique uses multiple transmit antennas at the base station but only one receive antenna at the mobile. The base station transmits with one antenna that is switched when the mobile informs the base station that the received signal has fallen below a fixed level. The implementation of switched diversity with feedback in a digital mobile radio system is first described, and then the bit error rate performance of the system is analyzed with fading as a function of several design parameters. Implementation of the system is shown to be relatively simple, yet the system is shown to reduce substantially the required received E b /N 0 for a given error rate at the mobile as compared to a system without diversity. For example, with five transmit antennas the required received E b /N 0 for a 10-3bit error rate is 13 dB less. The system capacity and availability assuming 32 kb/s audio and flat fading is then discussed. It is shown that with three-corner base station diversity and four transmit antennas at each base station, 126 two-way circuits per cell can be used in a fully loaded 40-MHz bandwidth system with a ten-percent probability that the error rate exceeds 10-3.

System identification in communications system

Abstract: In communications systems, such as cordless telephone systems, in which synchronizing signals are transmitted at predetermined intervals on a signalling channel by base stations to say portable, battery-powered receivers, the need to send separate station identification signals is avoided by the synchronizing signals being transmitted from a base station in accordance with a predetermined signalling sequence, for example a pseudo-random sequence, and the receivers using the sequence as a base station identification signal.

Optimal channel reuse in cellular land mobile radio systems

Abstract: Origination probability for cochannel interference is introduced to the study of the influence of all cochannel interferers surrounding the base station of interest. In addition, the probability of cochannel interference, which is of importance in determining system parameters in a cellular communication scheme, is evaluated for the mobile radio environment as expressed by Rayleigh fading and shadowing. As a consequence, the optimal number of radio channels to allocate to each cell is derived through the use of a simple mathematical model. The theoretical results obtained are useful not only as a step in the maturation of the cellular land mobile radio system, but also for the development of the portable radio telephone system.

Method and means for allocating the volume of traffic over different control channels of a cellular radio system

Abstract: A cellular radio system in which the mobile radio stations in the zone of any base radio station assign themselves to the control channels allocated to that base station so as to evenly spread the volume of traffic over such control channels. The base station transmits on each control channel a channel group code signifying the range of group code numbers allocated to that particular control channel. Each mobile station stores its identifying group code number, scans the group code numbers of all control channels, and assigns itself to the control channel having a channel group code which includes its group code number. The spread of traffic over the various control channels can be changed by the base radio station simply by changing the channel group codes of the various control channels, without addressing specific commands to the mobile radio station.

Radio paging method of arranging message information with reference to a key code and a base station and a pager receiver for use in the method

Abstract: In a radio paging method of transmitting message information from a subscriber's substation (32) through a base station (30) to pager receivers (31) in the form of a radio calling signal, the message information is divided into a plurality of species to which key codes are assigned, respectively. When a selected one of the key codes is indicated from the substation prior to transmission of the message information, the base station sends a request to the substation in compliance with the selected key code to receive, as the message information, a message indicated by the request. The indicated message preceded by the selected key code is carried from the base station to the pager receivers by the radio calling signal. Each pager receiver reproduces the indicated message with reference to the selected key code. The substation comprises a push-button telephone set to send each message to the base station. Preferably, an audio response unit (46) is included in the base station to send the request by the use of an audio signal. It is also preferred that the radio calling signal should comprise call number signals of a low bit rate for calling selected ones of the pager receiver with the message information transmitted in the radio calling signal either at a high bit rate or at a plurality of high bit rates.

Power supply systems for use in radio communication systems

Abstract: In a power supply system for use in a radio communication system comprising a base station for transmitting and receiving radio signals, one or more repeater stations for repeating the radio signals, and a terminal station communicating with the base station through the repeating stations, the base station comprises means for transmitting synchronizing signal pulses at a predetermined period for effecting a battery saving type power supply. Each of the repeater station and terminal station comprises means, responsive to successive reception of a predetermined number of the synchronising signal pulses, for effecting intermittent battery saving at a period substantially equal to the period of the synchronizing signal pulses during occurrence of the synchronizing signal pulses.

A location monitoring system

Abstract: In a location monitoring system for monitoring the location of a plurality of mobile units operating on preestablished routes from a centrally located control station, and where each mobile unit (14) communicates partly with a base station (10), partly with signposts (15, 16) located in specific positions along the known routes, from which the mobile units (14) receive position-specific information during passage, the transmitters (12, 15) in both the base station (10) and in each individual signpost (15, 16) are arranged to have the same operating frequency (F1). This saves an extra receiver in each of the mobile units (14) while minimizing the need for transmission channels. Moreover, the antenna (16) of the signpost has been given a signal emission in a narrow range around it and with such signal strength that the message acceptance to the signals of a signpost (15, 16) during the passage thereof is reasonably good (50%), and at the same time the probability that a message from the base station (10) is not received is very low (=0.1).

An Integrated Voice/Data System for VHF/UHF Mobile Radio

Abstract: This paper presents the basic architecture and performance of a mobile radio multiaccess voice/data system. Natural pauses in conversational speech allow bandwidth saving through interleaving of data packets and talkspurts from different voice sources. A speech detector designed specifically for the mobile environment is presented. Blocking and delay performance of the multiaccess uplink is analyzed for voice traffic, assuming no traffic effects from the low priority data packets. Performance results from simulation are then presented for two downlink strategies in a two-hop virtual circuit in which a base station acts as a relay. The results verify also that the uplink analysis is valid for low voice traffic. For the data traffic, simulation results are presented in terms of data packet transmission delay and probability of collision with talkspurts. The results indicate that data flow may be limited by the collision factor. This work concludes that relative to conventional radio telephoning in which two channels are dedicated to each transmitter/receiver pair, a bandwidth reduction of 30-35 percent can be achieved.

Cellular mobile radio

Abstract: C ELLULAR MOBILE RADIO holds the promise of meeting the increasing demand for mobile telephone channels. In this paper, we describe the cellular mobile radio concept, with emphasis on the two key features of a cellular system: frequency reuse and cell splitting. W e also briefly discuss the history of mobile radio and recent FCC decisions resulting in the present situation. Finally, we describe two methods for achieving improved coverage of remote locations:, a satellite-augmented terrestrial radio system and an HF-augmented system. Mobile telephone service has traditionally been expensive and cumbersome, with a grade-of-service substantially 1,ower than that provided by fixed landlines. Despite these problems, the demand for service has far outstripped the available capacity in many major cities, resulting in long waiting lists for service. Modern technology has made possible a significant increase in the efficiency of mobile radio through frequency reuse and sophisticated system control. In this paper, we discuss recent FCC decisions that have changed the future of mobile radio. W e then describe the cellular concept in some detail and discuss some potential future applications.

Process for spreading the volume of traffic over different control channels of a cellular radio transmission system

Abstract: A system and process is described for spreading the volume of traffic over different control channels of a cellular radio transmission system A base station having at least two control channels subdivides the number of mobile radio stations in a cellular area of the base station into groups, of a variable number of groups The base stations transmit the number of groups and a group code on each control channel The mobile stations receiving the transmitted information detect the number of groups and group code of each channel The mobile radio stations will combine the number of groups and the received group code with the stored group number The result of this combination determines the channel over which the mobile station control is to be assigned

Alternative cell configurations for digital mobile radio systems

Abstract: This paper introduces a novel class of antenna configurations and applies it to cellular digital mobile radio systems with frequency reuse. Directional antennas are used extensively. Cooperation between more base stations than are in the conventional three-corner directional antenna scheme is required for the alternative cells. The paper studies the relationship between signal-to-cochannel interference and trunking efficiency (availability of channels) and compares conventional systems with the same base-station locations. We concluded that the new antenna configurations can significantly improve trunking efficiency. Time-division retransmission systems with space diversity are considered for some cases. Furthermore, we show how transmitter power weighting (i.e., certain transmitters have higher output power than others) can improve the signal-to-cochannel-interference ratio for the novel cellular systems.

Mobile radio communication system

Abstract: PURPOSE:To economize the equipment of subscribers and to eliminate locations of noncommunication, by unifying a subscriber telephone system consisting of each mobile radio communication system and connecting a subscriber to a communication network from any location by one kind of device. CONSTITUTION:An exchange station 1 includes a charging logger at each mobile subscriber and a device storing the present position. A mobile subscriber 5a sets a radio line to a base station 3n at outdoor places. When the subscriber 5a enters a building 8, it is connected to a cordless telephone master set 6A. Subscribers 4a-4m on cars set radio lines to the base station 3a. When the device 4a enters the underground of the building 8, it is connected with the 6A. The mobile subscriber device is provided with a transmitter/receiver connectable to base stations 3a-3n or master devices 6A-6Y. A detector to which the base station or master device is to be connected at the position of the station itself, is provided and the connection increasing the quality of communication is selected. A device selecting the transmission power switchingly depending on the connection is provided. The charging information of the mobile subscriber is recorded on an imposition device of the exchange station 1.

Radio transmission method for a mobile radio system

Abstract: In a radio transmission method for a mobile radio system, a link between a mobile station and a central station is established via one of several base stations. The selection of the base station is done by the mobile station in accordance with radio-engineering criteria, and only the transmitter of the selected base station is keyed. This makes the method economical with respect to frequencies, on the one hand, and on the other hand, requires little operational effort for the chain of base stations.

Security system for cordless extension telephones

Abstract: In a cordless extension telephone system in which a base station is connected to telephone lines and communicates with a remote station by radio transmission, the base station in response to the presence of a ring signal on the telephone lines repeatedly transmits an eleven bit code at a predetermined bit rate. The remote station upon receiving the eleven bit code at least three times in succession generates an audio signal to indicate the presence of a incoming call. The user at the remote station may actuate a control to an "on" position or an "off" position. The remote station responds to the actuation of the control and will repeatedly transmit the eleven bit code plus one additional bit having a state indicating whether the control is actuated to the "on" state or the "off" state. The base station in response to receiving the eleven bit code at least three times in succession will enble or disable an isolation circuit in accordance with the twelfth bit of the code. The isolation circuit when enabled, will apply the signal on the telephone lines to the input of the transmitter of the base station and the output of the receiver of the base station to the telephone lines.

Cordless telephone system

Abstract: A cordless telephone system has a base station for connection to a telephone line, and a handset arranged for duplex radio intercommunication. Both base station and handset are microprocessor controlled and each has a non-erasable non-volatile read only memory for storing a unique digital access code. The base station has a receiver section 30, and a transmitter section 10 arranged automatically to transmit the code stored in its memory in the form of a FSK modulated signal when an incoming call is present on the telephone line, the handset having means for comparing the transmitted code with its own stored code, so that, if the two codes match, an audible ring signal is emitted. Similarly, the handset (Figs. 3,4) is arranged automatically to transmit the code stored in its memory either when the user switches it on to make a user- originating call, or when it is switched on by the user in reply to the ring signal. In this case, the base station detects the transmitted code, compares it with its own internally stored code, and if the codes match, transmitter and receiver circuitry in the base station is connected to the telephone line.

Performance of a Transmitter Diversity MSK Mobile Radio System with Two Bit Differential Detection

Abstract: The error rate performance of a transmitter diversity using frequency offset MSK signals and 2 bit differential detection in land mobile radio communication systems is derived under the general conditions of additive Gaussian noise, cochannel interference and fast Rayleigh fading. Numerical results and useful design curves are presented for cases of practical interest and compared with the case of no diversity. Transmitter diversity can be used in the base stations when simplicity is required in the receiver at the mobile units.

Mobile radio communication system

Abstract: PURPOSE:To eliminate the influence of a hit accompanying zone switching when a moving body has data communication, by storing data in a buffer memory temporarily in case of the hit, and read the data out of the buffer memory and transmitting it after the communication recovers from the hit CONSTITUTION:A mobile equipment has a data equipment 3, a data processor 1, and the buffer memory 2 Data from the data equipment is transmitted normally directly to a base station 11 without being passed through the buffer memory 2 When the mobile equipment changes from the zone of the base station 11 to the zone of a base station 12 during communication, the communication has a break, but the current data from the data equipment 3 is stored in the buffer memory 2 temporarily and taken out of the buffer 2 after the zone switching is completed; and said direct communication which is carried out without the intervention of the buffer 2 is restarted after the data in the buffer 2 are all taken out

Informing system of caller number for incoming call during absence

Abstract: PURPOSE:To decrease the incompleted call rate, by storing a caller number and a called party member as to the call given to a mobile body during the absence of a subscriber and informing the numbers to a mobile body subscriber CONSTITUTION:When the absence of a mobile body subscriber is confirmed at the calling of a mobile telephone set 21, a common controller 2 of a mobile body exchange 23 stores the caller number to a storage device 5 corresponding to the subscriber number of the absent mobile body Further, when the called mobile body subscriber restores to the state using the telephone set 21 and dials a specific number, a radio system signal device 7 of the exchange 23 is received via a ratio base station 22 Since the received calling information includes the caller mobile body subscriber number, the device 2 reads out the caller number of the incoming call during the absence and transmits the caller number from the device 7 This number passes through the base station 22, is received at a handset of the telephone set 21 and displayed on a numerical display 13

Transmission output control system in mobile communication

Abstract: PURPOSE:To preclude the possibility of deviation out of the permissible limit of same frequency interference at a good radio wave propagating condition by receiving a measured value of a received wave level by at least one of a mobile station and a base station and changing a transmission output of the transmission station in response to the reception level of a reception station so as to avoid disturbance such as suppression of sensitivity on other channels. CONSTITUTION:A reception wave reaching a mobile station as a multiplex wave reflected and scattered on a building or the like and received on an antenna 16 is separated by a transmission/reception common use set 17 and inputted to a receiver 18. The detected output of the receiver 18 is measured by a level measuring circuit 19, its output is compared with an output of a reference level generating circuit 21, and after the detected difference is superimposed on the voice inputted from a voice input terminal 27 at a modulation circuit 26 so as to modulate a carrier, the result is transmitted to an opposite radio base station via a transmitter 23, the transmission/reception common device 17 and the antenna 16. On the other hand, a data signal in the output of the receiver 18 is demodulated and the demodulated data is fed to a control circuit 29. The control circuit 29 obtains the transmission output of the transmitter 23 in response to the demodulated data and changes the transmission output of the transmitter 23.

Continuity test system of mobile radio communication

Abstract: PURPOSE:To shorten a communication interruption time with regard to channel switching accompanying zone transition by testing the continuity of a new channel while holding communication over the last channel and switching the communication to the new channel on the completion of the continuity test. CONSTITUTION:A mobile equipment 9 has two transmitter and receivers 2 and 3 and a changeover switch 12. When the switching to a base station 7 is necessary while the mobile equipment 9 communicates with an equipment connected to a connection control network 8 through a base station 6 over a radio channel 4, the connection control network 8 acquires a radio channel 5 newly between the transmitter and receiver 3 and base station 7 while holding the communication over the channel 4. The continuity of this new radio channel 5 is tested, and when the continuity is normal, the switch 12 is changed over to the side of the transmitter and receiver 3. The connection control network 8 switches the communication path between the network and base station to the communication path between the network and the base station 7.

Intermittent reception system of mobile station in mobile radio

Abstract: PURPOSE:To reduce power consumption by performing an intermittent reception where a mobile station in the stand-by state receives a required time slot only through the reception of a calling control channel. CONSTITUTION:A time slot S transmitted simultaneously from N sets of radio base stations is transmitted to obtain the information representing the presence of a mobile station in a control zone and a time slot Si transmitted individually and sequentially is transmitted respectively to obtain the information such that in which radio zone the mobile station exists. The mobile station discriminates in which radio zone it exists by detecting the reception level of N sets of slots Si and finding out the slot of maximum level, and obtains the information relating to the radio zone from the slot having the maximum reception level and other (N-1) sets of slots are not required. Thus, the mobile station receives intermittently only the Si of the maximum reception level and the slot S so as to reduce the power consumption.

Empty car response system for taxi radio machine

Abstract: PURPOSE:To grasp accurately numbers of empty cars, by calling the empty cars from a base station with an aural signal and encoding response signals in the empty cars and transmitting response signals time-differentially from the empty cars. CONSTITUTION:A base station calls empty cars with an aural signal, and a polling signal is transmitted when a press button is turned off at the end of calling. When a mobile station receives the polling signal, a timer is operated by the fall of this signal. Operating times t1-t7 of timers are different in mobile stations. When a response button is depressed in the mobile station to respond to the call signal, a signal obtained by encoding the car number of the mobile station is transmitted to the base station just when a corresponding time-out of operating times t1-t7 of timers is elapsed.

Sound storing and reproducing method in mobile radio equipment

Abstract: PURPOSE:To transmit completely the content of a job from a base station of other mobile stations, by transmitting the message of the operator stored in advance automatically and storing the message of the base station or the other mobile stations automatically, corresponding to a selective callout from the base station of the other mobile stations when the operator of a mobile station is absent. CONSTITUTION:While the operator is absent, when electromagnetic waves from the base station or the other mobile stations are received at a receiver 4 via an antenna 1 and an antenna switching device 2 and a call signal is detected, a detection signal is transmitted from the receiver 4 to the control section 8. Thus, a control signal is transmitted from the control section 8 to a sound- encoded data storage/readout section 5 to read out a digital signal stored in a transmission-side sotrage/readout device and the digital signal is transmitted via a transmitter 3, the antenna switching device 2 and the antenna 1. The base station or the other mobile stations can recognize that the operator is absent from the said message from the mobile station during calling. Thus, the base station or the other mobile stations transmit the message accordingly.

Channel switching test system of mobile communication

Abstract: PURPOSE:To attain the channel switching test between two arbitrary radio base stations, by remote-controlling a virtual mobile station for line test provided to a radio base station from a monitoring and controlling console CONSTITUTION:When a line test registration and an operating line reservation are performed from the control of a monitoring and controlling console 6, the line connection is done between fixed telephone sets connected to a car telephone exchange station 7 and a line test virtual mobile station in a monitor controller 3 of a station to be monitored to confirm the possible call In this state, when a channel switching test command is transmitted from the console 6, a monitor controller 5 gives a command to reduce the output level of the virtual mobile station to the device 3 and transmits a channel switching command so as to attain channel switching to a radio base station 8' to be switched registered in advance When a connection controller 2 discriminats the reduction in the level of the virtual mobile station for line test, a level decreasing signal is transmitted to a radio line controlling station 4 The controlling station 4 receives the level information from all the radio base stations to check whether or not the maximum level information address is coincident with the switched address

Communication system for mobile radio reservation

Abstract: PURPOSE:To impartially process all the waiting of subscriber mobile stations, by performing reserved registration for a base station, when no vacant communication channel exists in the base station. CONSTITUTION:The information whether or not a vacant communication channel exists is transmitted on a control channel 4 from a base station, and when no vacant communication channel exists, the information whether or not the reserved registration is possible is transmitted. At a mobile station, the channel selection at an outgoing call is controlled according to the information from the control channel, and when the vacant channel exists, the mobile station is connected to the vacant channel designated by the base station, and when the reserved registration is possible, the reservation is done. When the reserved registration is impossible, it is displayed and as soon as a vacant channel is generated after the communication traffic is usable, the call can be permitted in the order of registration.

Multiplex access system in mobile radio communication system

Abstract: PURPOSE:To attain multiplex access by means of one communication line by allowing a radio bass station to apply polling based on he information registering a zone presence of a mobile communication processing station. CONSTITUTION:When a station MSS1 is moved from a zone A to a position where a base station MSB2 applies polling to a station MSS2 of a zone B, the MSS1 registers the position in the zone B and informs the own presence zone to the MBS2. The MBS2 adds the MSS1 to a polling list PL and applies sequentially polling to the MSS1 and MSS2. The base station MBS revices the list PL attended with the movement of the mobile MSS and applies polling to the mobile MSS in this way, allowing to use the one communication line and attain multiplex access.