Showing papers on "Base station published in 1971"
••
TL;DR: In this article, computer simulations of high-capacity mobile radio systems using different channel assignment philosophies are described, which initiate call attempts and move vehicles about randomly according to prescribed statistical distributions.
Abstract: Computer simulations of high-capacity mobile radio systems using different channel assignment philosophies are described. These simulations initiate call attempts and move vehicles about randomly according to prescribed statistical distributions. Base stations and radio channels are assigned to serve mobiles and system operating statistics are accumulated. Relationships between systems parameters obtained from the simulation are presented. Performance of a dynamic channel assignment system (DYNSYS) which has all channels available at all base stations is compared with performance of a fixed-channel assignment system (FIXSYS) which reserves channel subsets for use at specific base stations. For uniform spatial distributions of call attempts and 40-channel systems with reuse intervals of four base station radio coverage areas, the DYNSYS outperforms the FIXSYS at blocking rates up to 13 percent. For example, at a 3 percent blocking rate the DYNSYS provides 20 percent more calls “on” in the system.
123 citations
•
25 Jun 1971
TL;DR: In this article, a central control computer considers the status of use of all communication channels utilized by the system and determines a channel which may be advantageously assigned to a mobile user via a preferred one of a plurality of spacially remote base stations.
Abstract: To determine a channel which may be advantageously assigned to a mobile user via a preferred one of a plurality of spacially remote base stations, a central control computer considers the status of use of all communication channels utilized by the system. All of these channels constitute but a single set, so any of them may be assigned to a mobile user by way of any base station. Thus, the allocation procedures utilized by the computer feature optimization tests which insure minimal station-to-station interference with optimal "packing" and re-use of the channels over the entire system.
77 citations
•
13 Apr 1971TL;DR: In this article, a billing classification is discriminated on the basis of a dial signal sent from a vehicle and the result of the discrimination is sent from the exchange equipment in the form of a voice-band multifrequency signal, also serving as a response signal, so that the condition for the billing is set in the vehicle.
Abstract: In a mobile communication system wherein connection is provided between a vehicle and an ordinary telephone network through one of the radio base stations which are installed within a district in which the vehicle passes the radio base station being connected to an exchange station associated with the telephone network, a billing system in mobile communication, wherein an out-band signal is sent from the vehicle to an exchange equipment in the exchange station whereupon a second out-band signal is sent from the exchange equipment to the vehicle so that, only while the second out-band signal is being received, measurement of time and billing are carried out in the vehicle, and wherein a billing classification is discriminated on the basis of a dial signal sent from the vehicle and the result of the discrimination is sent from the exchange equipment to the vehicle in the form of a voice-band multifrequency signal, also serving as a response signal, so that the condition for the billing is set in the vehicle.
16 citations
••
TL;DR: In this article, the authors summarized the ideas that are being actively discussed for use in mobile radio and, in particular, how they apply to the new 900-MHz region assigned to the Land Mobile Radio Services category.
Abstract: This article summarizes the ideas that are being actively discussed for use in mobile radio and, in particular, how they apply to the new 900-MHz region assigned to the Land Mobile Radio Services category. Over the next decade some of these methods will prove out and others will probably fall by the wayside. It is clear, however, that some new techniques will be necessary if mobile radio is to continue its growth.
9 citations
•
IBM1
TL;DR: The reliability and efficacy of traffic control in multiple station exigent radio communications is assured by a digital data communication system having accelerated polling and lockout of satellite or circumjacent subordinate station transmitting apparatus when the subordinate stations are contending for the attention of the central or base station as mentioned in this paper.
Abstract: The reliability and efficacy of traffic control in multiple station exigent radio communications is assured by a digital data communication system having accelerated polling and lockout of satellite or circumjacent subordinate station transmitting apparatus when the subordinate stations are contending for the attention of the central or base station and/or a circumjacent station is located in an area of unfavorable radio wave propagation Duplex frequency operation with the central station continuously broadcasting messages and/or synchronizing characters, assures synchronization and resynchronization immediately on receipt of a single synchronizing character Contention is evaluated in the central receiving apparatus by determining the level of optimum signal-to-noise ratio and measuring the rms value of distortion to establish reception parameters for controlling the mode of the radio net operation A busy signal is then broadcast for locking out all transmission from the subordinate stations except for that one station accepted Similarly an indication of field strength is obtained at subordinate station receiving apparatus by a threshold detector arranged to lock out the transmitting apparatus for propagation levels predetermined as unreliable and in a mobile situation to notify the operator to move the station to a better location for communication Current flow in the second limiter stage of an FM receiver is suggested as a base measurement over a predetermined time period to prevent backlash Confirmation, acknowledgment, and roll call are controlled by a polling character transmitted at the end of a message Circuitry responsive to these characters is arranged for conducting an accelerated poll for effecting a single bit response from each circumjacent transmitter addressed specifically in a poll as listed in a predetermined time assignment For the latter arrangement a shift register used for normal data processing is arranged to double as a counter for this purpose Changeover delay is obviated by effecting transmission at a predetermined later bit time Subordinate stations are addressed in general, in groups or as individual stations as best suits the purpose at the central station Each character comprises identification bits and a control bit Circuitry responsive to the latter bit is arranged to lock out the transmitter when the central receiving apparatus is busy Overall capacity of the system is enhanced by interposing message buffer stores for each transmitting and each receiving apparatus
4 citations
•
15 Oct 1971TL;DR: In this article, a call forwarding arrangement for use in a telephone switching system wherein a call directed to a base station may be established to a remote station arbitrarily chosen by either the base or an attendant station user is presented.
Abstract: A call forwarding arrangement for use in a telephone switching system wherein a call directed to a base station may be established to a remote station arbitrarily chosen by either the base or an attendant station user. Base station and attendant station users are each enabled to dial remote station directory numbers into a digit register. Digital pulse trains representing the registered remote station number are serially read into an idle remote station store of a content addressable memory. Additional pulse trains representing the digits of the base station number are serially read into a base station store associated with the remote station store. The memory is interrogated by simultaneously comparing the serial digital pulse trains of a called station number with serial digit pulse trains read from every base station store. On a pulse match condition digital pulse trains are serially read from the remote station store associated with the matched base station store into the telephone switching system in order that a call may be established to the chosen remote station.
3 citations