Abstract: A method of collapsing a communication path among at least two communication units (104-107) reduces the number of sites normally required to provide a communication. Each of a plurality of site controllers (103) in a radio communications system has a corresponding coverage area (100, 101), and at least some of the coverage areas (710-712) overlap one another. The method includes the step of determining (402) whether the communication units are currently being serviced by different sites, and then determining (405) whether they can be serviced by a common site. When the communication units are serviceable by a common site, the call might be established (406) through the common site, resulting in a reduced number of sites required to complete a call.

Abstract: Linking of radio paging transmitters is accomplished through the utilization of TDM transmission on the same channel as that assigned to the paging service, thus eliminating the necessity of a separate channel for linkage of the remote transmitting sites to a central originating location. For data transmission, real time data is broadcast via a direct RF link to buffer storage at each of the remote transmitting sites, with the data being read out to each of the paging transmitters from the local buffers in a phase-adjusted synchronized fashion under control of sync signals generated at and broadcast from the central originating location. The data transmission rate from the central originating location to the remote sites may be made significantly higher than the radio paging data rate in order to minimize link time to minimize linkage overhead by reducing the amount of time the channel is used for linkage as opposed to paging.

Abstract: A central controller of a communication system network may more efficiently expand an audience of a communication in the following manner. When a communication unit of a first communication group within a first communication system transmits a request for service, the central controller determines whether the audience of that predetermined communication is to be expanded. When the audience of the predetermined communication is to be expanded, the central controller combines at least part of at least one other communication group with the first communication group based upon a predetermined grouping arrangement. Having combined the groups, the central controller processes the predetermined communication among the communication units in the first communication group and the communication units in the at least part of the least one other communication group.

Abstract: A radio communication system includes a central station such as a repeater for transmitting FM signals to a plurality of radios. The repeater 11 is capable of receiving both analog speech FM signals and compressed voice signals. This permits the use of energy efficient transmission schemes by some of the radios operating in the system while permitting use of both types of transmission by the various remote radios.

Abstract: A communication system (10) comprises a portable radio (20) and a plurality of mobile repeaters (12), a mobile repeater system 200 comprising a portable signal receiver (224) for receiving portable radio signals; a mobile transmitter (218) for transmitting the portable radio signals received by the portable receiver; a mobile receiver (226) for monitoring mobile transmissions; a delay state counter (202) for delaying the transmission of the portable radio signals received; and a received signal strength indicator (204) for determining the strength of received mobile radio signals, the received signal strength indicator being coupled to the delay state counter, via a controller (206), for decrementing the delay state counter when the mobile receiver does not detect a mobile transmission having at least a predetermined received signal strength level.

Abstract: A communication installation for use in a site having underground galleries, for information exchanges, comprises a repeater connected to a wired distribution network. The repeater is arranged for receiving messages which arrive over the wired network at a first frequency and for retransmitting the messages over the network at a second frequency different from the first frequency. The network comprises non-radiating cable sections, radiating cable sections capable to radiate at the second frequency and to collect radiation energy at the first frequency from a portable emitter-receiver set placed nearby. The network further comprises terminal antennae for emitting at the second frequency and collecting energy at the first frequency.

Abstract: A system and method for handing back a movable transceiver to a different cell site from the original cell site includes circuitry for sensing signals from the movable transceiver which are transmitted on a modified frequency as well as circuitry for translating those signals back to their originally assigned frequencies without changing the detected field strength of the signal, in combination with circuitry for forwarding the translated signals to the different cell site for hand-off evaluation. The method includes sensing the received signals, translating the received signals to an originally assigned frequency based on either a fixed offset or other provided information concerning the translation along with a step of continually updating those frequencies which are to be retranslated.

Abstract: In a cellular system, including at least one cell site located within a corresponding geographic sector, an apparatus and method provides for expanding cellular system capacity through subdivision of the geographic sector by use of a cell site transceiver and a remote site transceiver to extend said cell site to a remote location within said geographic sector. Each transceiver provides duplex operation and includes a cellular band transmitter and receiver portion for local communication with the cell site or remote site mobile units, as the case may be; and a link frequency transmitter and receiver portion for communicating cellular band information, after conversion to an appropriate baseband frequency, between the cell site and the remote site transceivers.

Abstract: A diversity receiving apparatus includes first and second antennas and circuitry for selecting one antenna or the other. Control circuitry analyzes signal strength received from the selected antenna and determines when the antennas should be switched. The antennas are switched when the received signal strength falls below a running average thereof; the received signal strength falls below a threshold value; or a predetermined time has elapsed since the antennas have been switched. The antennas are switched when the received signal strength falls below a running average thereof; the received signal strength falls below a threshold value; or a predetermined time has elapsed since the antennas have been switched.

Abstract: Independent communication systems are provided with additional receivers that allow the systems to monitor one another's outbound control signalling channels. Secondary control signalling can be interleaved with the primary control signalling information on this communication resource, which secondary control signalling information is intended for reception and use by the monitoring system.

Abstract: A method and apparatus for distributively interconnecting a plurality of land mobile trunked transmission communication systems into a wide area network includes a plurality of distributive radio network terminal (RNT) switch means and a unique signaling protocol and a switching protocol especially adapted for communication of control signals in the subaudio band for interconnecting the trunked transmission communications systems into a wide area network that provides an expanded feature set of radio communications capabilities.

Abstract: A repeater (30) is provided for relaying communication between a subscriber unit (24) and a central station (10) when the repeater recognizes transmission from the subscriber unit to the central station but detects a lack of response by the central station to that subscriber unit or when the repeater recognizes a transmission from a subscriber unit (26) requesting the repeater for service. The repeater asks the central station for a channel upon which to communicate. Alternately, a predetermined channel may be used for the relayed communication.

Abstract: A meteor burst communication network is disclosed that consists of a plurality of meteor burst communication stations that relay radio messages off of meteor burst trails from one station to another. Each station includes an antenna operably coupled to a receiver and transmitter, a display, a message input device, a computer operably connected to the aforementioned equipment, and a clock that provides a time base to the computer. The computer provides instructions to the transmitter and outputs to a display. The program determines if a message has been received by the receiver. If a message has been received, it is stored in the computer memory. The computer then instructs the transmitter to transmit a probing message for a predetermined period of time.

Abstract: A vehicular repeater interrupts the repeated audio and a timing signal that is transmitted to the portable. The timing signal is used by the portable to determine when the vehicular repeater will next interrupt the repeated information. Accordingly, the portable synchronizes its transmission of a signal to coincide with the next interruption. If no transmission is desired, the portable operates to mute the portable's speaker during the interruption to prevent noise bursts. Upon the initial recipt of a portable+s transmission signal, the vehicular repeater extends the interruption interval to verify the portable's transmission signal.

Abstract: An apparatus for detecting excessive output power from a cellular radio telephone system booster includes input circuitry for receiving incoming radio frequency signals from a mobile source. Amplifiers are provided for amplifying the radio frequency signals either directly or by means of intermediate frequency channels. The output power amplifiers have variable gain. Circuitry detects when the transmitted radio frequency signals exceed a predetermine threshold and reduce the amplifier gain accordingly.

Abstract: A mobile communications system uses a communications satellite and a Mobile Telephone Switching Office (MTSO) and communicates with mobile units via the satellite. A cell site has a co-located cell site converter which converts satellite signals to signals for the MTSO and vice-versa. Remote converter sites communicate with the satellite and with the mobile units in given geographical areas. A single satellite link is sufficient for adequate RSA service. Frequency and phase differences among signals from the remote sites to the satellite are synchronized to avoid frequency- and phase-drift.

Abstract: A diversity receiving apparatus includes first and second antennas and circuitry for selecting one antenna or the other. Control circuitry analyzes signal strength received from the selected antenna and determines when the antennas should be switched.

Abstract: A radio signal relay system for use with dispatch communication systems is disclosed. The radio signal relay system includes a linking device constructed with a first and a second full duplex transceivers such that it has the capability of communicating with the communication controller and at least one repeater in each of at least two adjacent communication systems.

Abstract: A trunked communication system wherein channel assignment information is provided to a requesting subscriber unit in a dual word format that includes separate and specific information regarding both a transmit frequency and a receive frequency. The transmit and receive frequency information is provided in a coded form, which can be decoded by the subscriber unit with reference to a table of information stored therein in conjunction with a simple algorithm.

Abstract: A repeater for a wide area coverage multiple repeater system (100) includes a receiver (220) and a transceiver (230). The receiver (220) receives a received signal from a portable or mobile communication unit (130) on an inbound channel. The received signal is routed to a receive signal strength indicator (RSSI), a bit error rate (BER) detector, or a similar devices for differentiating a received signal quality characteristic. The transceiver (230) includes a transmitter (232) for repeating the received signal on an outboard channel and a receiver (234) for monitoring presence of an outboard channel activity. A controller (260) enables the transmitter (232) to retransmit the received signal, based on the received signal quality characteristic, and in absence of the outboard channel activity.

Abstract: A distributed radio antenna system for extending radio communications into confined regions into which external radio signals do not penetrate, the system having separate transmitting (TX) and receiving (Rx) antenna systems. Each Tx or Rx system has an elongated low loss coaxial cable system (18 or 31) and a plurality of antennas (23 or 28) connected to each of the individual segments of the cable system at spaced distances along the length of the cable segment. The antennas are coupled to the cable segments by signal taps (21 or 21') having adjustable or preselected values of attenuation so that the power fed to each TX antenna (23) from the Tx cable system (18) is approximately the same and so that the attenuation of the signals received from each Rx antenna (28) is approximately the same, thereby conserving power and reducing system cost.

Abstract: In antenna arrays having normally unexcited or little-excited elements, a technique for configuring the array to provide both global and spot beam coverage, wherein the normally unexcited or little-excited elements are excited at a higher level, together with other normally excited elements to provide spot beam coverage, the normally unexcited elements being left unexcited to provide global beam coverage. Ring redundancy configurations for amplifiers in a transponder provided in the configuration are optimized to minimize additional hardware requirements. The specific example of the INMARSAT II satellite system is discussed.

Abstract: For use in a cellular radio-telephone system to enhance a signal from a cell site in an area shadowed by an obstruction such as a building or a mountain or the like, and to receive signals from subscribers in such areas, a cell enhancer includes bidirectional receivers, transmitters and amplifiers, the receivers and transmitters both including duplexer circuits for coupling signals in the proper up-link and down-link bands to the proper up-link and down-link antennas for transmission. Two embodiments of amplifiers are disclosed. A wideband amplifier network includes an input duplexer, a wideband amplifier with an attenuator, and an output duplexer, the duplexers coupling signals from both the up-link and down-link duplexer circuits to the amplifier for amplification. A narrow band network includes a plurality of amplifier modules each of which amplify only on one up-link and down-link channel assigned to the cell.

Abstract: A radio communications system operational within the medium frequency range for underground mine communications, coupling MF carrier signals into existing conductive channels extending to within the mine and devices within the mine and coupled to the conductive channel for receiving the MF carrier signals and communicating with portable and mobile transceivers operational within the MF frequency range and in the common seam mode.

Abstract: Direct relay equipment includes a first antenna, a second antenna, an up direction circuit connected from the first antenna via a first circulator to the second antenna via a second circulator, and a down direction circuit connected from the second antenna via the second circulator to the first antenna via the first circulator. In the up direction circuit and the down direction circuit, the received signal having a frequency f.sub.1 from the first (or second) antenna is amplified by a microwave amplifier, the output of the microwave amplifier is converted to a signal having a frequency f.sub.2 (sending frequency), the signal having the frequency f.sub.2 is amplified by the same amplifier, and the amplified signal having a frequency f.sub.2 is sent from the second (or first) antenna.

Abstract: A telemetering system for a data transmission line having a sequence of repeaters controls sequential operation from a centralized single supervisory terminal. The supervisory terminal sends an interrogation signal forward to a first repeater which sends back an answer signal relating to the status of that repeater and also sends the interrogation signal forward to the second repeater. In addition, status answer signals received from said subsequent repeaters in the sequence are transmitted backward through the repeater chain to the supervisory terminal. Thus, each repeater acts on the telemetering channel as a bidirectional repeater, repeating forwardly the interrogation signal and repeating backwardly its answer and the answer of subsequent repeaters in the sequence. Eight status parameters are detected at each repeater and monitored at the supervisory terminal.

Abstract: A wide area coverage radio communication system of the type adapted to relay a message substantially simultaneously from a plurality of fixed location sites to a plurality of portable or mobile units includes a plurality of repeaters at each of the sites. Each of the repeaters is arranged to transmit and receive on a respective different frequency duplex pair or channel. Control means at one of the sites senses channel availability at all of the sites and causes one repeater at each of the sites to transmit the message on its respective different frequency. Access to the system by the portable units is provided on a trunked basis through the control means.

Abstract: A repeater for a transmission system which can pass signals in either of two directions. Each direction has a signal detection circuit associated with it. Upon detection of the beginning of a signal, the signal detection circuit enables an associated driver to pass the signal in the appropriate direction and at the same time disables the other signal detection circuit so that a signal will pass in only one direction at a time. An end flag detecting circuit monitors for certain characteristics associated with the end of the signal, and upon detection causes both drivers to be disabled and both signal detection circuits to be reset so that they can again detect a signal passing in either direction.

Abstract: An improved multifrequency trunked, two-way communications system is provided in which a plurality of conventional single channel radio units are provided access. The system includes a predetermined number of information channels that are shared by a plurality of trunked stations. A trunked controller assigns one of the information channels to a requesting trunked mobile unit. The requesting trunked mobile unit is enabled to operate on the assigned channel in response thereto.The improved communications system includes a radio access link which enables the single channel radio units to operate on an assigned information channel in the same manner as the trunked remote stations. The radio access link provides the plurality of conventional remote stations automatic access to the trunked system without requiring any modification of the conventional remote stations, and likewise without modification of the trunked remote stations and trunked controller.

Abstract: A mobile vehicular repeater detects the termination of a received transmission from a portable transceiver to be repeated and, in response to such detection, activates the up-link radio transmitter so as to send an acknowledgement signal to the message originating portable transceiver station signifying the probable successful conclusion of a repeating operation. Special techniques are utilized to prevent confusion between such an acknowledgement signal and similar prioritizing transmissions on the up-link frequency.

Abstract: In satellite communication systems it is often necessary to relay the signal between terminal stations and the satellite through ground relay stations remote from the terminal stations. Normally, in systems using composite multi-carrier signals for transmission through the satellite, the composite multi-carrier signals are reduced to baseband in the ground relay station prior to retransmission. To reduce the amount of equipment and the cost of such a ground relay station, a method and apparatus for relaying the composite multi-carrier signal through the ground relay station without reducing it to baseband in the ground relay station is provided. Thus, with this arrangement, the composite multi-carrier nature of the signal is preserved throughout the ground relay station.

Abstract: In a radio communication system, an adaptive transmitter power control system is described wherein the signal level at each receiver is monitored and a control signal, which is a function of the signal level, is transmitted back to the transmitting station to adjust the transmitter output power, as required. By transmitting the lowest power level consistent with system objectives, the repeater circuits operate in a highly linear mode, and cochannel interference is significantly reduced.

Abstract: Each customer location is equipped with a remote terminal which contains a role code identifying the remote terminal as an end device and a plurality of address codes. A plurality of signal repeaters are each connected with certain of the remote terminals through a distribution network. Each signal repeater contains stored route and role codes as well as a unique address code allowing each signal repeater to be additionally addressed as an end device. A central station produces an outgoing communication signal intended for at least one end device. A communication link couples the central station to the power distribution network. The communication signal includes a route code identifying a signal path to the end device, a role code identifying the first device in the identified route, an address code and a message code. Upon receipt of the communication signal by a signal repeater which is not the intended end device, the received route and role codes are compared to the stored route and role codes.

Abstract: An electrical-optical interface network for use in a carrier-sense, multiple-access system with collision-detection provides two-way transmission between an electrical circuit (5,7,9) and a pair of lightguides (21,22), but prevents signal transmission between the lightguides.

Abstract: The system comprises two terminal stations connected through a two-wire transmission line including bidirectional repeaters. The duration of each half-duplex cycle between successive emissions of two digital packets from a terminal station is independent of the length or range of the line. In particular, the half-duplex cycle duration is less than the transmission duration of two packets along two opposite transmission directions for a line having a great length. The system is characterized in that at least one of repeaters comprises a memorizing circuit for delaying each packet which is received along one of the transmission directions, with at least two times the duration of a packet, thereby retransmit it after the transit of another packet along the other transmission duration through the repeater.

Abstract: Monitoring system for a forward and backward link equipped with two way repeaters-regenerators comprises a monitoring station including means for transmitting through the forward link information data and a low frequency control signal and for receiving through said backward link information data and supervisory words respectively monitoring the performance of the repeaters-regenerators and identifying errors made therein. In each repeater regenerator a supervisory word is stored in a shift register and advance pulses for said shift register are obtained by frequency division of the low frequency control signal. The supervisory word is completed by a start bit and a stop bit, and modulates the low frequency control signal. The modulated start stop supervisory word is transmitted to the monitoring station through the backward link.

Abstract: Apparatus for frequency multiplexed radio links between a control transceiver and at least two operator transceivers, said apparatus being of the type in which the control transceiver comprises on the one hand a transmitter receiving a low frequency signal from a microphone and transmitting a high frequency wave Fe and on the other the same number of receivers as there are operator transceivers, each receiver being adjusted to a particular high frequency Fi which differs from Fe, each receiver supplying a low frequency signal which is directed to a loudspeaker and in which each operator transceiver comprises on the one hand a receiver adjusted to the said frequency Fe and supplying a loudspeaker and on the other a transmitter connected to a microphone and operating on one of the said frequencies Fi, wherein it also comprises means located in the control transceiver for reinjecting part of the low frequency signals supplied by each of the receivers of the control transceiver into the transmitter of said transc

Abstract: A frogging signal repeater for a transmission line communications system such as a telephone system having a trunk line connected between a pair of signal sources such as end central offices and/or standard signal repeaters. Each signal source generates information signals on a group of relatively high frequency carrier signals and receives information signals on a group of relatively low frequency carrier signals with the frogging signal repeater connected in the trunk line for translating the high and low frequency groups.

Abstract: The present invention discloses an FM microwave radio frequency repeater using the straight-through system for relaying signals of a plurality of channels having different carrier frequencies, each of the channels including an auxiliary channel. The system according to the invention is characterized in that the auxiliary channel has the signals thereof demodulated through frequency discrimination of a difference frequency signal obtained by mixing together two received microwaves.