Abstract: A payload design for a multi-spot-beam satellite communication system includes a plurality of uplink spot beam receivers and downlink spot beam transmitters, and a broadcast transmitting subsystem capable of transmitting a broadcast beam to an entire system geographical service area. An input filter-switch-matrix (IFSM) controllably selects input IF signal bands for routing to an on-board digital signal processor-router (DSPR). The DSPR subsequently routes all received point-to-point and broadcast data packets to the appropriate downlink spot or broadcast transmitting subsystems for transmission thereof. The broadcast downlink allows broadcast transmissions to occur at the highest efficiency possible, while also allowing for flexible provision of surge capacity for point-to-point transmissions on previously exhausted spot beams by selective use of the broadcast beam for such point-to-point transmissions.

Abstract: A system and method for converting carrier frequencies of a wireless communication system is provided. The system and method allow expansion of coverage areas of wireless communication systems, such as a mobile/cellular telephone system. In one embodiment, the system converts RF signals in the PCS band to ISM band, and transmits the ISM signals to a distant repeater station. The repeater station receives the ISM signals and down converts the ISM signals to the PCS band. The PCS signals are retransmitted in a new cell thereby creating a new coverage area. Radio frequency signals are down converted to an Intermediate frequency for channel selectivity and narrow band filtering. Channel selectivity circuitry allows quick reuse of other channels in the same cell. The channel selectivity circuitry includes a SAW filter which significantly reduces out of band interference.

Abstract: The present invention relates to a method and apparatus for selectively enabling and disabling transmit and receive functions of a radio, and more particularly to a system and method utilizing an out-of-band signal over a time division duplex channel to control transmit and receive functions of a radio so as to synchronize with the functions of a remote modem. The invention relates to a system and method for synchronizing the transmit and receive modes of a radio via an out of band signal. The out of band signal is preferably a control tone at a predetermined frequency and is substantially coextensive with the communication signal to be transmitted. The radio filters a multiplexed signal and detects if the control tone is present. If the control tone is not detected, the radio preferably remains in the default receive mode. If the control tone is detected, the radio operates in the transmit mode for the duration of the control signal.

Abstract: An apparatus and method for identifying remote communications transmitted via a repeater from remote communications not transmitted via the repeater. The method comprises the steps of receiving a plurality of signal transmissions originating from a plurality of remote stations, wherein each of the signal transmissions is associated with a call originating from one of the plurality of remote stations; processing the plurality of received signal transmissions to identify received transmissions that include a discriminant applied by a repeater; and designating each of the plurality of received signal transmissions as being transmitted via the repeater if the received signal transmission includes the discriminant.

Abstract: An apparatus and method for filtering a signal in a phase lock loop is disclosed. An typical apparatus for filtering a phase error signal comprises a first filter subcircuit receiving a phase error signal from a phase comparator and filtering the error signal when enabled, a second filter subcircuit receiving the phase error signal from the phase comparator and filtering the error signal when enabled and first and second enable switches which are activated in combination to control filtering of at the error signal. The first filter subcircuit is enabled by activating a first combination of the enable switches and the second filter subcircuit is enabled by activating a second combination of the enable switches. A fast acquisition subcircuit can also be used to temporarily underdampen the filter and improve overall performance of the phase lock loop circuit. The filter can be used to obtain multimode operation in a cellular radio.

Abstract: A repeater system for transmitting and receiving RF signals to and from an area obstructed by a mountain, a building, etc. One antenna is linked to the base station antenna of, for example, a cell in a cellular network, and another antenna is directed to the obstructed area. Signals are received by one antenna from the base station antenna and digitally separated into a number of different frequency channels. The separated channels are then transmitted by the other antenna into the obstructed area to mobile users. Also, signals from the mobile users are received by one of the antennas and similarly digitally separated into different frequency channels and transmitted to the base station antenna for delivery to a communication network.

Abstract: A transmit processor that includes a transmit frequency domain equalizer (TX FEQ) that pre-compensates packets in the frequency domain to flatten transmit filter response to improve spectral mask and reduce PER. The TX FEQ taps may be selected so that the average power at output equals the average power applied to the input. The TX FEQ may be designed to yield 64 QAM packets with no quantization distortion at the input of an Inverse Fast Fourier Transform (IFFT) processor. The 64 QAM constellation map points and TX FEQ gain values are selected to avoid exceeding the bit resolution of the IFFT processor. The tones may be bound together into zones to reduce implementation complexity by reducing the number of TX FEQ taps.

Abstract: An apparatus and method for identifying remote communications transmitted via a repeater from remote communications not transmitted via the repeater. The method comprises the steps of receiving a signal transmission 124A from a remote station 112, determining if the signal transmission 124A includes a discriminant applied to the signal transmitted from the remote station 112 and designating the signal transmission 124A as being transmitted via the repeater 120 if the signal transmission 124A includes the discriminant.

Abstract: On embodiment of the system and method provides asymmetric adaptive modulation which allows uplink and downlink subframes of data to be transmitted between a base station and a CPE with different modulation schemes, thus increasing the efficiency of downlink transmissions while maintaining the stability of uplink transmissions. In systems with multiple CPEs, each CPE and base station pair can independently select their uplink and downlink modulation techniques. The system and method are also adaptive in that they adjust the modulation schemes based on, for example, signal to noise ratio measurements or bit error rate measurements.

Abstract: Channel fluctuation estimating section 101 estimates fluctuation amount of the channel between transmitting apparatus 100 and receiving apparatus 200, and carrier number determining section 102 determines the number of subcarriers used in transmission of signal based on channel fluctuation amount. That is to say, in the case of a remarkably rapid channel fluctuation caused by fast fading, etc., carrier number determining section 102 deduces relatively the channel fluctuation between symbols or within a burst, by decreasing the subcarriers number and increasing symbol rate per one subcarrier.

Abstract: A system and method for converting carrier frequencies of a wireless communication system is provided. The system and method allow expansion of coverage areas of wireless communication systems, such as a mobile/cellular telephone system. In one embodiment, the system converts RF signals in the PCS band to ISM band, and transmits the ISM signals to a distant repeater station. The repeater station receives the ISM signals and downconverts the ISM signals to the PCS band. The PCS signals are retransmitted in a new cell thereby creating a new coverage area.

Abstract: The invention discloses a method and apparatus for supporting increased capacity on a backhaul communications link carrier frequency of a wireless communication system the uses a repeater station. Uplink RF carrier signals from a plurality of mobile units each having a first modulation scheme, are received at a serving repeater station. These uplink signals containing traffic and control information are demodulated and then re-modulated by a second modulation scheme having a higher-order modulation than the first modulation scheme. The re-modulated signal containing a plurality of uplink carrier signals within a single RF carrier signal is then transmitted over an uplink channel of a backhaul communication link. Additionally, the invention discloses a method for aggregating data on the uplink channel of a backhaul communications link. A plurality of uplink RF carrier signals from a plurality of mobile units are each received at a repeater station.

Abstract: The present invention provides a system for dynamically translating between a first communication protocol and a second communication protocol, said system comprising: means for receiving a first communication signal utilizing said first communication protocol; means for determining said first communication protocol; means for initiating a first communication protocol translator to extract data from said first communication signal in accordance with said first communication protocol and for storing said data in a buffer; and means for retrieving said data from said buffer and translating into a second communication stream utilizing said second protocol.

Abstract: Uniform and concentrated radio broadcast signals are obtained employing an antenna structure which uses separate antenna conductors on opposite sides of a radio reception area. The antenna conductors perform similarly to the plates of a capacitor. Highly efficient antenna performance results. In a preferred embodiment wherein the antennas are used for radio testing inside a vehicle assembly plant, the track or carrier structure of the vehicle assembly line provides one of the antenna conductors.

Abstract: Telecommunication services are provided to subscriber-provided radiotelephones (50) residing inside an aircraft (20). Telecommunication services are provided while the aircraft (20) is flying and utilize the aircraft's air-to-ground communication system (48) to access a radio communication link (34). Base stations (40) residing in aircraft (20) are configured to transmit at least two independent overhead control data pilot signals (54, 58) in response to instructions from a single controller (44). The control data pilot signals (54, 58) capture and control the subscriber-provided radiotelephones (50). Controlling methods are employed to force autonomous registration of radiotelephones (50) and to instruct radiotelephones (50) to transmit at minimum power levels.

Abstract: A data carrier processing system is provided for receiving an amplitude-modulated carrier signal. The system includes rectifiers and a voltage limiter that limits the d.c. supply voltage that is provided by the rectifiers. The voltage limiter provides a delayed response to amplitude variations in the carrier signal, so as to avoid adverse effects on the modulation of the carrier signal, while also providing an un-delayed response to excess amplitude values, so as to avoid excessive d.c. supply voltage for circuit elements of the data carrier system.

Abstract: For determining the operating point of a non-linear amplifier 2 of a communication channel 1, for example of a transponder in a communication satellite, a first input signal I1 is transmitted through the communication channel 1 at a power level PI1 which drives the non-linear amplifier 2 in a non-linear operation mode. In addition, a second input signal i2 is transmitted through the communication channel 1 simultaneously with the first input signal I1. The second input signal i2 is transmitted at a level below the level of the first input signal I1. If the contribution of the second input signal i2 to the total input of the non-linear amplifier is small, the operating point of the non-linear amplifier is determined almost only by the first input signal. Therefore, the output power P02 corresponding to the second signal i2 is determined most strongly by the input power PI1 of the first signal I1.

Abstract: A plurality of transmitting and receiving stations are provided at randomly distributed locations within a telecommunication network, and switching circuitry is provided within the stations themselves for routing of calls between stations in the network utilizing other stations in the network for relaying of such calls where necessary. To this end each station incorporates a call routing control unit acting to select a further station to which a call from a source to a destination is to be transmitted for the purpose of relaying the call. The call routing control unit transmits an interrogation signal to be received by other stations in the network within range of the transmitting station, and the call routing control unit of each of the other stations transmits an acknowledgment signal when the station is available for relaying a call in response to the interrogation signal received from the station.

Abstract: A payload design for a multi-spot-beam satellite communication system includes a plurality of uplink spot beam receivers and downlink spot beam transmitters, and a broadcast transmitting subsystem capable of transmitting a broadcast beam to an entire system geographical service area. An input filter-switch-matrix (IFSM) controllably selects input IF signal bands for routing to an on-board digital signal processor-router (DSPR). The DSPR subsequently routes all received point-to-point and broadcast data packets to the appropriate downlink spot or broadcast transmitting subsystems for transmission thereof. The broadcast downlink allows broadcast transmissions to occur at the highest efficiency possible, while also allowing for flexible provision of surge capacity for point-to-point transmissions on previously exhausted spot beams by selective use of the broadcast beam for such point-to-point transmissions.

Abstract: An arrangement of an area covering, cellular radio communication network having cell regions which can be contiguously replicated without interference. A central transceiver station is coupled to a base station controller and has a plurality of decentral transceiver stations surrounding and coupled to the central transceiver station. Groups of adjacent decentral transceiver stations are grouped in respective cell areas. All of the decentral transceiver stations in each cell area are allocated the same transmission frequencies, but the frequencies of each cell area are different from the other cell areas in the cell region.

Abstract: A mobile telephone repeater with a variable bandwidth is disclosed. The repeater comprises an uplink and downlink, each being provided with amplifier chains (6). Each chain comprises at least two band pass filter units (10, 11) coupled in series and having controllable pass bands, which at least partially overlap each other. The center frequency of the filter units are controllable so as to make the bandwidth of the resulting pass band variable. Consequently, the effective bandwidth of the amplifier chain is controllable.

Abstract: A booster system for transmitting a received wave after amplifying it comprises a receiving antenna section, a carrier combining section, a transmitting section, a transmitting antenna section and a parameter control section. The carrier combining section multiplies a canceling signal by a cancel parameter to obtain a replica signal, then combines it with a received signal in at least one of the radio frequency band, the intermediate frequency band and the base band, and derives a combined base band signal from the combined signal. The transmitting section generates a send signal and a canceling signal by using a signal demodulated through the demodulation of the combined base band signal. Based on the combined base band signal and the canceling signal, the parameter control section determines a canceling parameter such that the power of the combined base band signal is reduced, the parameter being provided to the carrier combining section.

Abstract: Transponder systems are disclosed for routing signals from a plurality of input frequency channels at each of a plurality of receive antennas to a plurality of output frequency channels at each of a plurality of transmit antennas. The routing is preferably processed at an intermediate frequency. A plurality of bandpass filters are coupled to each receive antenna to define input signal paths. First and second mixers are positioned in series with each bandpass filter. A mixing signal at the first mixer adjusts the frequency of a selected one of the input signals to pass it through the bandpass filter and onto the respective input signal path. A mixing signal on the second mixer translates the frequency of that input signal to have a frequency order in the intermediate frequency band that corresponds with the frequency order of a selected one of the output frequency channels at its respective transmit antenna. Each of the transmit antennas is coupled to a common signal path of an adder.

Abstract: A wireless communications system includes a number of clusters of repeaters wherein all repeaters within a cluster arc connected to a common hub via respective millimeter-wave radio links. Wireless signals received by the repeaters from end-user devices are transparently carried by the millimeter-wave radio links to respective hubs that act as concentrators for the repeaters. The hubs may be linked to a wireless network base station (in an outdoor setting) or alternatively to a server or a PBX (in an indoor environment) via a high-speed transmission facility, such as a fiber optic cable that is thus shared by all the repeaters.

Abstract: A digital cellular radio communication system having a remote repeater is provided. The communication system includes a central communication site which: transmits and receives signals in a first radio channel assigned according to a cellular communication system channel reuse plan, transmits signals to and receives signals from a cellular communication network unit, and digitally processes received signals for subsequent transmission in the first radio channel or to the cellular communication network unit. The communication system further includes a remote communication site, substantially remotely located from the central communication site, which: receives a signal in either the first radio channel or a second radio channel assigned according to the cellular communication system channel reuse plan, channel shifts the received signal between the first and the second radio channels, and transmits the shifted signal in the other of the first and the second radio channels.

Abstract: An improved repeater for receiving and re-transmitting radio signals for a cell in a cellular telecommunication system. The repeater raises the levels and is capable of converting the frequencies of the radio signals used in the telecommunication system. Due to the power amplifiers being provided between the channel selecting means and combiner, the power amplifier needs only to amplify one frequency band. In this way the repeater gets a simpler design, demands less maintenance, and gets a higher degree of efficiency in combination of high power capacity and generation of low levels only of intermodulation products.

Abstract: A multiple channel radio frequency repeater has a receive port for receiving an input signal from a first antenna and a transmit port for transmitting a frequency shifted output signal to a second antenna. An input bandpass filter is located at the input port. A low noise amplifier follows the input bandpass filter for amplifying all signals within the input bandwidth. A plurality of channel filters divide the input signal into a plurality of channel signals. A local oscillator generates a local oscillator (LO) signal. There is a mixer corresponding to each channel, each mixer has an input port, an output put port and an LO port. The LO port is coupled to the local oscillator. An Automatic Gain Control (AGC) amplifier is between each channel filter and each mixer for adjusting the channel signal level to the mixer input port to assure that each mixer has the same level amplified channel signal.

Abstract: An amplifier with adaptive output capacity allocation (201) including a processor (203), coupled to a signal, for examining the signal to determine a first capacity requirement and a second capacity requirement, and an amplifier (213), coupled to the processor and the signal, for processing the signal in accordance with the first capacity requirement and the second capacity requirement to provide an output signal thus maximizing power out of the amplifier given incoming signal conditions.

Abstract: A communication apparatus is disclosed which is capable of measuring levels of carrier signals used in adjacent zones during telecommunication with a small circuit scale, and capable of simultaneously transmitting/receiving to FDMA-system signals through a plurality of communication channels. All of transmission signals received through the communication channels under use are wholly converted into an intermediate signal by a mixer. The intermediate signal is quadrature-detected and then A/D-converted into digital I/Q-channel signals by A/D-converters. Thereafter, the digital I/Q-channel signals are frequency-converted by frequency converting circuits in such a manner that center frequencies of these I/Q-channel signals become zero, two sets of I/Q-channel signals may be demodulated by two sets of demodulating circuits. Otherwise, one of these I/Q-channel signals is demodulated by a single demodulating circuit, and the other is level-detected by a level detecting circuit.

Abstract: The object of the invention is to employ a single amplifier for both the transmit and the receive signals in an RF repeater for interfacing with a base station for exchanging transmit and receive signals in a time division duplex cordless telephone system. A multicarrier amplifier having an input and an output and a transfer switch connected to the amplifier output and the amplifier input and having first and second switch states. The operation of the switch is controlled so that the transmit and receive signals are amplified by the amplifier. The other object is to chain RF repeaters so that the handset can roam over a roamer corridor covered by the RF repeaters. The RF repeaters are provided with a dedicated signal link.

Abstract: An electronic paging system and method for transmitting paging signals over a broadcast network, such as a standard pre-existing commercial radio broadcast system, adds paging signals to a normal radio baseband signal for non-interferential co-transmission therewith over the existing standard radio broadcast transmission system. A telephone interface receives paging information via normal telephone lines. The paging information is used to pseudo-randomly frequency-hop a frequency-synthesized signal which is added to the baseband audio of a standard commercial radio signal. This composite signal is then used to modulate the standard commercial radio broadcast carrier in the normal manner. Mobile pagers, or "beepers," receive and selectively decode (i.e. pseudo-randomly frequency-dehop) the standard commercial broadcast signal to determine whether and which pager is being summoned, i.e. addressed.

Abstract: A digitally trunked radio repeater system provides substantial improvements in timeliness of channel acquisition and channel drop, and in reliability of critical control signalling. The system uses a much higher digital signalling rate than is typically found in prior art systems, and uses a control channel to convey digital channel request and assignment messages between the central site and mobile transceivers. The mobile radio transceivers transmit channel requests on the control channel (if no response is received, the mobile retries during a retry time window which increases in duration in dependence on the number of retries). The mobile transceiver switches to a working channel in response to an assignment message received on the control channel. Subaudible digital signals transmitted on the control channel and on active working channels allow late entry, shifting to higher priority calls, and other advanced functions.

Abstract: A communication base station system for transmitting data to a movable body includes a plurality of transmission sections, each of the transmission sections receiving a transmission data, modulating this received transmission data, and then converting the frequency of this modulated transmission data to a preset frequency and outputting a result. A control section monitors a status of use of the transmission sections, and if having confirmed at least two transmission sections that do not transmit any data, the control section outputs a specified signal instead of the transmission data to two transmission sections among the confirmed transmission sections. An amplification section collectively amplifies a plurality of output signals from the transmission section and a compensation circuit compensates for intermodulation distortion components generated in the amplification section based on an output of a transmission section that has received the specified signal and its respective transmission frequency.

Abstract: A booster usable in a radio telephone communication system can amplify and repeat both analog and digital representations of communications. The unit monitors control channel communications going to subscriber units and reverse control channel responses from subscriber units. When a digital traffic channel assignment is detected, the booster directs the subscriber unit to a different traffic channel pair. The booster communicates with the subscriber unit on the traffic channel pair assigned by it to the subscriber unit. The booster communicates with the cell site on the channel pair assigned by the cell site. Digitized communications from the subscriber unit are amplified only during the associated time intervals. Hence, other communications in different time intervals on the same message channel are not effected. Analog conversations and other message channels can be simultaneously boosted and retransmitted.

Abstract: A method of managing (150) an overlapping radio patch which allows a audio channel to be involved in multiple patches which are established at different dispatch positions. The method prevents interaction between channels that are not part of the same radio patch by maintaining dynamic profiles of channel assignments (153) and channel patches (155). Channel activity is tracked (157) and a connection instance count (CIC) is determined using the assignment and patch profiles as well as the channel activity. Audio connections are then managed (161) using the corresponding CIC's to dynamically switch connections. This ensures the connections are in place only when needed thereby avoiding any latent connections which would contend for network resources. The invention allows for the implementation of a composite channel concept which improves the overall capability of radio dispatch services in a multi-channel, multi-dispatcher environment.

Abstract: In a multi-site communication system (100), audience continuity of an established communication group call can be maintained by a central controller (116) in the following manner. Upon initial establishment of the call, the central controller (116) allocates a communication resource (105-108) of each site in a first set of sites (101-104) to the communication group and establishes an audience list of active communication units (111-115). The audience list is continually updated with information on newly transmitting communication units and relocation information of communication units already in the list throughout the group call. When the group call ends, the audience list is maintained for a predetermined period of time. If during this predetermined period of time, a subsequent group call is requested for the same communication group, the group call can be re-established based on the information contained in the audience list.

Abstract: A gateway between a non-trunked ("conventional") RF communication system and digitally trunked RD communication system maps between trunked group IDs and non-trunked subaudible signalling tone frequencies. An interface between the two systems thus forms a "super group" including both trunked and non-trunked radios that can automatically communicate together. The gateway permits a customer to continue to use non-trunked components, and to cost-effectively integrate such components into a state-of-the-art trunked radio communications system.

Abstract: A dispatch radio communication system (100) employs a method (200) and apparatus (101) for assigning one of a console station's control modules (113-115) to a communication resource. The assignment is initiated by associating (203) each control module (113-115) with a group of supported resource features and associating (205) each communication resource with a group of employed resource features. The latter association is then used to establish (211 ) a minimum set and an extended set of resource feature requirements for a particular communication resource that is to be added to a console station (109). The former association is used to identify (217) a group of candidate control modules (113-115) at the console station (109) that can support at least the minimum set of resource feature requirements. Upon identification of the candidate group (113-115), the candidate control module (e.g.

Abstract: Apparatus for simultaneously receiving a plurality of AM signals of widely differing strengths on a set of carrier frequencies and for re-broadcasting the AM signals at equalized strengths at either the original carrier frequencies or at a set of carrier frequencies that are offset from the original from the received frequencies by a constant difference. Regardless of whether the re-broadcast carriers are offset, the system includes provision for interrupting the re-broadcast signals by an audio message of general interest or public safety.

Abstract: In a cellular communication system where satellite nodes are moving with respect to the earth's surface, frequencies and time-slots are dynamically reallocated between cells in response to demand for services. When a particular cell is at or near its capacity because of a high demand for services, or is projected to be at or near capacity, spectral capacity is reallocated from nearby cells to meet the increase in demand. The reallocation in capacity is based on both real time cell loading data and historical cell loading information based on previous experiences.

Abstract: A method to implement multiple talk-around communication links using the communication resources of one repeater. A system resource controller determines whether talk-around is possible for any two communication units intending to engage in a point-to-point communication link. Assignment of a talk-around repeater depends on the geographic locations of the two communication units, and a predetermined range criterion between them. In addition, the talk-around communication must not interfere with any existing talk-around communication already in the system. When talk-around communication is possible, an enabling communication grant is issued to the units, and the talk-around repeater's communication resources are assigned to support the link. Otherwise, a repeater for normal trunking is assigned.

Abstract: In a secure trunked communication system that includes a central controller, communication between a distribution panel and a limited number of console interface units may be achieved in the following manner. At power up or upon a reset condition, the distribution panel transmits a status check message to each console interface unit in the system. Console interface units that are active respond by transmitting an acknowledgement. Upon receiving the acknowledgement, the distribution panel transmits the addresses of the active console interface units to the central controller. When the distribution panel receives secure information from the central controller, it interprets the information to identify a target console interface unit and transmits the received secure information to the target console interface unit.

Abstract: An automatic repeater station, sometimes called a relay system, is disclo. The relay system receives signals, preferably at one band of frequencies, then filters and restores their inherent information, and finally transmits the restored information, preferably at another band of frequencies. Unlike the prior art systems utilizing transceivers and electronically tunable filters, the present invention uses separate receivers and transmitters and is devoid of electronically tunable filters.

Abstract: A multiple channel demand assignment multiple access (DAMA) system is configured as a spoke-and-hub star network in which a satellite relays information between each of many small-aperture terminals (SATs), which may be portable terminals (PTs), and a hub network control terminal (NCT) which receives requests from the PTs, allocates channel resources, and broadcasts housekeeping messages. The system has a reservation protocol using at least three separate data channels to take advantage of the inherent lack of adequate radiated power at the PTs: a NCT outbound channel is tightly packed with data, without guard spaces, and it uses typically 98% of the allocated power; separate return channels for data and reservations use little satellite power, with no need for extremely tight data packing. Guard spaces are included in the reservation channel to overcome the total range of propagation delay uncertainty without requiring knowledge of the location of a particular PT.

Abstract: An RF repeater for interfacing with a base station for exchanging transmit and receive signals in a time division duplex cordless telephone system comprises a multicarrier amplifier having an input and an output and a transfer switch connected to the amplifier output and the amplifier input and having first and second switch states. The switch means connects receive signals from the handset to the amplifier input and the amplifier output to the base station in the first switch state, and connects the base station to the amplifier input and transmit signals from the amplifier output to be broadcast to the handset in the second switch state. The operation of the switch is controlled so that the transmit and receive signals are alternately amplified by the amplifier. Thus, only a single amplifier is required.

Abstract: In a trunked radio frequency communications system, a dynamic regrouping scheme includes an effective user interface, automatic support of multi-site systems, the capability to program individual radio transceivers with multiple new groups dynamically, a fast rate of reconfiguration, instantaneous switch over to prevent radios from residing in immature groups, and a satisfactory mode of operation should the site controller (or site controllers in non-fault tolerant systems) fail. Some of the dynamic regrouping features includes unlimited prestored plans and source and destination groups per plan, regrouping at the plan or destination group level, an advanced user interface, automatic support of multiple sites, fast regrouping at the rate of over 30 radios per second while reducing loading on the system control channel, and fast activation/deactivation. Each plan can be immediately activated or deactivated and users are effectively regrouped together.

Abstract: A radio relay system including a water-proof conductor housing on which is located a pair of antennas, one antenna being used for transmitting and receiving radio carrier wave signals of a first and a second frequency, respectively, while the other antenna is used for transmitting and receiving radio carrier wave signals of a third and a fourth frequency, respectively. A skirt for each of the antennas is located adjacent the antennas on the housing, one skirt has a length equal to a quarter of the wavelength of the first frequency while the other skirt has a length equal to a quarter wavelength of the third frequency.

Abstract: A dispatch communication system wherein a communication unit may move from the service coverage area of a first system to the service coverage area of a second system during a communication transaction without the need to re-initiate the call. Communication units and base sites under this invention are constructed to relay signals to and from the system where the call originated.

Abstract: In a communication system network, a central controller can more efficiently respond to communication requests in the following manner. Upon receiving a request for a multi-communication system communication by a communication unit in a first communication group, the central controller determines that at least one of the communication systems of the multi-communication system request does not have an available communication resource in it, producing a non-accessible system. Having determined that at least one communication system is non-accessible, the central controller determines the average wait period for a resource to become available in each of the non-accessible communication systems.

Abstract: In a communication system network, an operator station, for a particular communication group, may select communication systems wherein a communication group service will be performed for the particular communication group. This is accomplished when the operator station selects, for the particular communication group, the group service to be performed and which communication systems the service is to be performed in. Once these parameters are selected, the operator station transmits them to the central controller which determines whether at least one communication unit of the particular communication group is registered in the selected communication systems. When at least one communication unit of the particular communication group is registered in the selected communication systems, the central controller allocates a communication resource in the selected communication system to the operator when a communication resource is available such that the selected communication group service can be performed.