Showing papers on "Base station published in 1990"

Polarization diversity in mobile communications

Abstract: Signals in the vertical and horizontal polarizations at the base station have been measured by transmitting from a principally vertically polarized mobile. There was no direct line-of-sight path between the mobile and base. The envelopes were uncorrelated and the means differed by 7 dB and 12 dB when the mobile was in urban and suburban areas, respectively. The discussion of the results includes theoretical curves showing the relationship between the envelope correction coefficient and the mean levels difference of Rayleigh distributed signals in orthogonal linear polarizations at the base station. The variable parameters are the rotation angle of the base station antenna and the crosspolar discrimination of the incident fields. >

Cellular radiotelephone diagnostic system

Abstract: A system and method of evaluating the radio coverage of a geographic area serviced by a digital cellular radiotelephone communication system is described which comprises a plurality of base stations each having a transmitter and a receiver and a plurality of mobile units having co-located transmitters and receivers for transmitting and receiving communication message signals between the base stations and a mobile unit. During operation, the position of at least one of the mobile units operating within the geographic area is located when a call is received by a base station. The base station monitors the signal quality of the call and collects information relevant to the actual performance of the communication system. The mobile unit location and corresponding signal quality data are passed from the base station to a central operation and maintenance unit which collects the data, performs all necessary analytic and arithmetic computations, and provides a user-friendly representation of the characteristics of the radio coverage. With this representation of the radio coverage characteristics, the system operator can quickly and efficiently diagnose coverage deficiencies and take the necessary corrective action. By continuously monitoring subscriber calls and updating the pictographic representations, the system operator can actually observe the effect of the adopted modifications in a pseudo real-time fashion.

System and method of load sharing control for automobile

Abstract: A system and method for load sharing processing operations between a vehicle mounted station (105) and a stationary base station (25) having a large capacity host computer (18) is described. The vehicle mounted station (105) has detectors for determining operating conditions of a vehicle and controllers (3,4,501) for varying the operating conditions. The controllers (3,4,501) are connected to a transmitter-receiver (5) which is arranged to communicate over a path (10) with a transmitter-receiver (11) of the base station (25). The base station (25) has a host computer (18) having a large memory capacity. At predetermined intervals, for example, distance of travel or at engine stop, the vehicle transmitter (5) transmits operating conditions to the base receiver (11) for data processing and the base transmitter (11) then transmits processed data back to the receiver vehicle (5), whereupon the controllers (3, 4, 501) modify the vehicle operating conditons. The vehicle operating conditions may be an indication of life expectancy of fuel injectors or sensors, updating data processing maps. The presence of abnormal operating conditions may be detected by the vehicle mounted station (105), evaluated by the base station (25) and an emergency warning indication provided back to the vehicle mounted station (105), or if the abnormal condition is not of an emergency nature then counter measures are transmitted from the base station (25) to the vehicle mounted station (105).

Radio communication system and a portable wireless terminal

Abstract: This invention proposes a radio communication system including a plurality of radio terminals, a relay apparatus (including a plurality of base stations and an exchange station) connected to each radio terminal so that the radio terminals can interchange information from each other, and a data processing unit connected to the relay apparatus, each radio terminal having a circuit for inputting and outputting a voice signal and a circuit for inputting and outputting data whereby it can communicate with another radio terminals or with the data processing unit through the relay apparatus. The radio terminal of this invention further has a clock, and a circuit for storing a schedule inputted by the user thereby to automatically select a receiving mode such as a ringing mode or a nonringing mode in accordance with the contents of the schedule, the present time and so on.

Mobile assisted handoff

Abstract: The invention relates to a method for communication and handoff in a cellular mobile radio system and a base station and a mobile station for communication and handoff in such a system, in which time slot identifier codes are transmitted in bursts in times slots in frames of radio channels used for time division communication channels, the time slot identifier codes being indicative of burst time slot in a frame but not of transmitter or receiver entity or radio channel, the time slot identifier codes being used for burst synchronization and determining bursts the signal strength of which to be measured for the purpose of possible handoff.

Data communication device

Abstract: Disclosed herein are two embodiments of an alarm and security system. The first is a stand alone alarm and security system which includes a control panel and at least one transceiver for sending and receiving a control signal and a base station. The control panel receives information about one or more desired conditions in one or more geographical areas and transmits the information to a base station via the transceiver. The base station receives the information from the control panel and transmits the appropriate control signals to the control panel. The second embodiment includes a communications panel including first transceiver for receiving information about one or more desired conditions in one or more geographical areas and for receiving a control signal and for transmitting the desired condition information and a control signal to a base station. Either embodiment accepts information from an existing panel via telephone line and transfers a full data message to the base station.

Mobile radio transmission system using preferred home service area

Abstract: A private mobile radio transmission system comprising a plurality of geographically spaced base stations (BS) defining a plurality of overlapping service areas (SA). The base stations are coupled for example by land-line communication links (CL) to a system controller (SC). Mobile stations (MS) equipped with simplex two-way radios are free to roam through the service areas. In order to be able to make a call with or via a base station it is necessary for the mobile station to be registered with the base station concerned. Details of the registration are stored by the mobile station concerned and the base station. In order to optimise on the usage of radio channels, details of a home base station are preprogrammed into each mobile station and when the mobile station wishes to register with a base station, it is instructed to try to register firstly with its own base station, on the basis that the majority of calls will be to and from the home service area and will require only one pair of frequencies, secondly with a base station of any other service area in its region, and thirdly with a base station of a service area in any other region. When registered with a service area other than its home one, the mobile station checks regularly to see if it is possible to register with its home service area.

Geodetic surveying system using multiple GPS base stations

Abstract: An improved system and method for determining a position fix in space and time using the Global Positioning System (GPS) satellite network signals. The system comprises at least three fixed base stations each having a satellite receiver operating in conjunction with a highly accurate (atomic-standard) clock. Each base station's position is known with great accuracy. GPS satellite signals are collected over statistically significant periods of time at each base station and fitted to determine with the clock offset and drift of the station clocks, thus establishing a "network" of base station clocks that in the aggregate is of great accuracy and precision. An arbitrary number of mobile receiver stations similarly collect data for working periods of statistically significant duration; these data are used in conjunction with the base station data to compute position fixes for the mobile stations.

Protocol and transceiver for cordless/cellular telephone service

Abstract: A communications system suitable for use with hand portable radio telephones operating in a cellular mode, the typical cell size being between 500 m and 3 km radius. Each cell comprising at least one primary or base station (10) connected to the PSTN and one or more secondary portable stations (14) which are capable of roaming within the cell. Radio communication between the stations can be initiated by either station. Each primary and secondary station having radio transceiving means for time division duplex communication between the stations, a codec operating at 32 kbits/second or 11.4 kbits/second and means for transmitting digitised speech in accordance with a framed structure comprising 3 full rate or 6 half rate channels per carriers, the carrier being modulated at a carrier bit rate of substantially 270.8333 kbits/second. Provision is made for internal and external handover, if required. Also, if required, the secondary station can be constructed to operate in the DECT system as well as in the above described system.

Mobile merchandising business management system which provides comprehensive support services for transportable business operations

Abstract: A computer based system is used for providing a comprehensive set of business support services for mobile business operations such as merchandising carts and kiosks. The services include: i.) providing a two-way computerized communication link between the mobile business unit and a headquarters base station via radio telemetry or ground lines, ii.) a data capture facility which polls a variety of intelligent devices, such as temperature sensors and inventory level indicators, packages the data for subsequent transmission to the base station and summaries the data for display on the mobile system control panel, iii.) a base station communication facility which transmits messages and computer commands to remote carts and kiosks and initiates outbound paging, iv.) a base station mass storage and reporting facility which stores historical data related to product sales, cashier settlement, inventory control and in bound messages for subsequent retrieval and reporting.

Method of locating a mobile station

Abstract: A method of providing an estimation of a mobile station's location in a cellular communication system having a plurality of base stations and mobile stations is disclosed. The mobile station's location is provided by measuring radio propagation parameters between the mobile station and each base station within propagation range of the mobile station. Then, a location probability density function (pdf) is found based on the measured radio propagation parameters. A joint probability density function (pdf) is then constructed by combining each individual function which is obtained. The location of the mobile station is then estimated from the resulting joint probability density function (pdf).

Optical fiber microcellular mobile radio

Abstract: A microcellular communication system includes optical fiber connections between a base station and opto-RF transducers located in a closely spaced grid. Radio-band signals are modulated directly onto laser outputs through the optical fibers for both transmission to mobile units or from the mobile units. The opto-RF transducers, housed in canisters, are mounted on telephone or power poles to provide radio link coverage to mobile and portable phones located in a microcell area, e.g., in a congested metropolitan area where space for a roof-top base station is very limited and expensive.

Mobile communications system

Abstract: A system for mobile communication includes a number of base stations 10, 13, 16, 20, 23, 26 with users 30, 31, 45 and 46. Associated with each base station is an interface unit 10a, 13a, 16a, 20a, 23a and 26a which packetises voice information and includes header information concerning user and destination addresses. These interface units tracks the movement of the various user by passing control blocks from interface unit to interface unit. Packets are routed via routing block 40 or 41 and switches 50-52. The stored information within the base station interfaces allows movement from one base station to allow to be handled without call loss.

Method and arrangement for dynamically allocating time slots to connections in a digital mobile radio system

Abstract: The present invention relates to a cellular mobile radio system. Each cell includes a base station, a plurality of mobile stations and radio channels, for transmitted digital information between the base station and the mobile stations. More precisely the invention concern a method and an arrangement for dynamically allocating time slots to connections on the radio channels, in order to increase the capacity on the radio channels. The maximum number of simultaneous connections on the radio channels will be more than the available number of time slots per frame. When there are more connections established on a first and a second radio channel than time slots per frame, the connections share the available time slots in accordance with a determined multiframe time slot allocation scheme known to the base station and the mobile stations. The base station is selecting one of the time slot allocation schemes in dependence on the speech activity on the two radio channels. Information on the multiframe time slot allocation scheme selected, is transmitted on the first radio channel, to the mobile stations, during guard spaces.

Channel assigning method in a mobile communication system

Abstract: According to a channel assigning method for use in a mobile communication system, a base station selects, in response to a communication connection request, a communication radio channel having an interference wave reception level which is obtained by a measuring unit and satisfies a quality conditions of a communication channel from a plurality of communication radio channels, and transmits information of the communication radio channel to a mobile station as an object of the communication connection request. The mobile station selects the communication radio channel transmitted by the base station, measures an interference wave reception level, and transmits the measurement result to the base station. The base station checks whether the measurement result satisfies the quality conditions of a communication path, and assigns the communication radio channel to the requested communication when the measurement result satisfies the quality conditions of a communication path.

Radio communications system adaptively assigning channels using power levels of idle channels

Abstract: In a mobile radio communications system comprising a control station and base stations, each base station is capable of sensing power levels of signals received on idle channels. In response to a polling signal periodically sent from the control station, each base station returns a signal indicating the detected power levels, the identifications of the idle channels, the identification of a busy channel or no-busy channel indication, and the identification of each of the base stations. The control station derives an interference table from the contents of the signals received from all base stations. The table defines interference coefficients between all pairs of base stations in matrix form according to the identifications of the idle and busy channels and the identifications of the base stations. From the interference coefficients a plurality of interference estimations are derived for all possible combinations of channels and base stations. A minimum value of the interference estimations is detected and the channels associated with the minimum value are assigned to the base stations. The assigned channel identifiers are communicated from the control station to the base stations.

Air-to-ground communication system

Abstract: An air-to-ground communications system is described for controlling multiple two way radiotelephone conversations between a large number of aircraft (53) and a network of base stations (51) that are capable of being interconnected to landline telephone networks (54, 116). Plural base station controllers (90) of the system, each dedicated to control one base station (51), are in turn controlled by a single central processor (52). Means are provided for matching each aircraft with an optimal base station to afford it the strongest available communication signals, and for dynamically allocating communication channels between the base stations. The central processor (52) is designed to manage the system by recording and recognizing usage patterns (525-530) and allocating channels to most efficiently use the available radio spectrum among all the aircraft (517, 519).

The GSM radio interface

Abstract: The groupe speciale mobile (GSM) digital cellular radio system, to be introduced into Europe in 1991, is the first standardised cellular radio system to use digital transmission. Given the novel design of the system considerable effort has gone into producing the system specifications. These have been centred on the two major interfaces present in the system ― the mobile switch to base station interface and the base to mobile station (radio) interface. The paper describes the GSM radio interface in detail, covering both the traffic and signalling channels

A method of adapting a mobile radio communication system to traffic and performance requirements

Abstract: A method in a mobile radio communication system for adapting the system and communication to prevailing traffic and performance requirements. According to the invention a mobile station inserts information on particular codes in its messages transmitted to a base station in response to an invitation message from the base station. The codes indicate whether a message is new or retransmitted and/or message age. The base station receives radio signals in time slots identified in its invitation message and estimates for each time slot based on radio signals received in the time slot whether the time slot is empty or busy, or whether the time slot is empty or correct. For each message received and understood the base station retrieves the code. The retrieved codes and the number of empty/busy/correct slots enable the base station to estimage prevailing system traffic and performance. Estimations on prevailing traffic and performance are used to control system parameters such as number of time slots following an invitation message.

Adaptive resource allocation in metropolitan area cellular mobile radio systems

Abstract: It is shown that microcellular structures which will be found in future high-density traffic metropolitan areas require the application of adaptive methods for efficiently allocating the radio resource. Different dimensions of adaptation-adaptive base station allocation, dynamic channel allocation, and adaptive power control-are considered in an integrated manner. To answer if and how the proposed methods can work together, a generic algorithm comprising the different adaptive approaches is introduced. This was complemented by the derivation and definition of a comprehensive set of evaluation criteria. For the evaluation a simulation environment is developed, based on a Manhattan-like road grid structure, and comprising corresponding traffic and propagation models. First results indicate that the combined application of the different adaptation approaches yields the best performance. >

Method for determining multiple interference in a mobile radio system

Abstract: The invention relates to a method for determining the total downlink or uplink interference percentage in the coverage area of a designated base station for a mobile radio system with a given channel plan. The invention provides for the need to carry out, after a conventional channel allocation has been carried out, a check of the extent to which total interference requirements are met. The method consists in that field strengths from all base stations are measured on all traffic routes within the geographical area of the mobile radio system. The interference is calculated at each point within the coverage area of a base station for each relevant pair of base stations, preferably base stations which are located in the same channel and base stations which are located in an adjacent channel. The interferences of all the relevant pairs of base stations are added in order to form the total interference at each point. The invention makes it possible to calculate the total interference percentage which constitutes the ratio between the length of road distance with disturbed coverage and the length of total road distance with coverage. The interference percentage is calculated suitably within a contour which limits the coverage area of the base station concerned.

Frame synchronization system among multiple radio base stations for TDMA digital mobile communications system

Abstract: A TDMA digital mobile communications system prevents TDMA frame synchronization from being asynchronous among radio base stations when a communication held by a mobile station is handed over from one service area to another A control station sends a reset pulse for TDMA frame synchronization to the radio base stations each being situated in a particular service area over communications cables In response, the radio base stations each generates a TDMA frame The control station has a synchronous signal generator for generating the reset pulse while each radio base station has a time delay adjustment unit for adjusting the time delay of the reset pulse The synchronous signal generator and the time delay adjustment units of the individual radio base stations perform measurement and setting such that a reset signal has the same time delay between the control station and all of the radio base stations Hence, regarding a TDMA signal which the mobile station receives, TDMA frame synchronization is immediately set up at the time of hand-over and thereby prevents a voice signal from being interrupted

Evaluation of a proposed handover algorithm for the GSM cellular system

Abstract: In the future pan-European cellular mobile telephone system of the 'Groupe Speciale Mobile (GSM)' of CEPT, the decision whether a handover shall happen can be based on a set of variables whose values are measured in the system. Some performance measures for handover algorithms are reported, and a simulation tool for the evaluation of a proposed GSM handover algorithm is described. Some results of the evaluation are included. Special attention is given to the time over which the sampled values are averaged. The evaluation is based on a model of a cellular network, where the radio propagation characteristics are assumed to follow a lognormal law with Rayleigh fading. For given routes of mobiles, measurements of the received signal level are obtained by simulation and fed to the handover algorithm. >

Antenna switching system

Abstract: An antenna switching system for handling high traffic sectors in a cellular radiotelephone system. The system switches the cell's base station transmitters (210) to sectors that have more mobile traffic than they can handle. The additional transmitters (210) increase the number of frequencies in the overloaded sector, thereby allowing a greater amount of mobile traffic to use the cell.

Handover criteria for city microcellular radio systems

Abstract: 1700 MHz attenuation and bit error rate (BER) measurements were conducted at the center of a major urban area in southern England in order to compile a radio propagation and BER database for handover criteria study in city microcellular radio systems. The focus of the experiments was to provide realistic data for handover simulation in typical city microcell environments, thus minimizing inaccuracies due to the inadequacies in propagation modeling. Results revealed the path loss followed the inverse third to fourth power law in majority of the cases using simple regression fitting. The short-term signal fading statistics varied with Rice factors in excess of ten down to zero, as the distance between the mobile unit and the microcellular base station increased. Computer simulation indicated that both RSSI (received signal strength indicator) and BER could be used as handover criteria. The optimal threshold level for handover request, however, differed from location to location. >

Digital signal processor for radio base station

Abstract: A digital FM base station radio having a dedicated digital signal processing (DSP) board operates on audio signals from RF links and land lines The DSP board detects, filters and generates tones and communicates information regarding these tones to a controller microprocessor on the central control board for the radio

Method of arranging radio control channels in mobile communications

Abstract: According to a method of arranging radio control channels in mobile communications, for covering a service area with a plurality of radio zones and causing base and mobile stations to exchange signals through the control channels, a broadcasting information transmission portion is assigned to the control channels. This broadcasting information is to be transmitted from the base station to each mobile station to broadcast information associated with radio zones. Information associated with control channel structure in units of base stations is broadcast to the broadcasting information transmission portion. A frequency and a time slot capable of causing the base station and the each mobile station to exchange the signals are determined on the basis of the pieces of broadcasting information and an identical number commonly recognized by the base and mobile stations.

Space diversity system switching transmission

Abstract: Fixed radio equipment serving as a base station includes a transmitter, a plurality of antennas, and a selective control circuit. The antennas are spaced apart from each other by a distance which minimizes a correlation of interferential fading. The transmitter modulates a carrier by identical signals to be transmitted during periods associated in number with the antennas and feeds the resulting bursts of the carrier time-serially to a selective control circuit. The selective control circuit delivers one of the successive bursts of the carrier fed from the transmitter to one of the antennas and then delivers another burst following the above-mentioned burst to another one of the antennas. Mobile radio equipment or station has a single antenna for receiving the identical signals transmitted time-serially from the base station. The mobile station selects and outputs either one of the received signals which has higher quality than the other.

Method of reducing the power requirements in a mobile radio receiver

Abstract: In a receiving circuit of a mobile telephone apparatus the incoming baseband signals are demodulated and equalized so as to compensate for deficiencies (multipath propagation) of the radio medium between base station and mobile telephone apparatus. It is not, however, always necessary to equalize the demodulated signals, for instance at low symbol rates or in the case of monopath propagation. According to the invention, time dispersion of the received signals is estimated prior to demodulation, and demodulation with equalization (3a) is effected when the time dispersion is established to be higher than a given value, whereas demodulation without equalization (3b) is effected when the time dispersion is lower than this value. This will enable the power consumed by the receiving circuit to be reduced, particularly in the listening mode of the apparatus.

Method and apparatus for locating which zone and sector of a mobile communication system a mobile station is in

Abstract: A location method and system for a mobile communication system having a plurality of zones and a plurality of sectors in each zone The location method and system locate a zone and sector in a zone where a mobile station is located In the location system a base station associated with each zone transmits a control channel signal and transmits a sector signal for each sector in the zone Each control signal of a zone differs from control channel signals of other zones Each sector signal differs from other sector signal and control channel signals A mobile station controller associated with each mobile station receives the control channel signals, determines which zone the mobile station is in as a location zone based on the received control channel signals, receives sector signals for sectors within the location zone, and determines which sector of the location zone the mobile station is in as a location sector based on the received sector signals