Abstract: A communication resource allocator can reduce control channel traffic for limited audience communications in the following manner. After receiving and granting a request for allocation of a communication resource by a communication unit, the communication resource allocator determines whether the request is for a limited audience communication. If the request is for a limited audience communication, the communication resource allocator periodically transmits the communication resource allocation until it receives an acknowledgement from each of the communication units in the limited audience communication.

Abstract: Communication systems (101, 102) having dedicated communication resources are provided with receivers (111, 116) that monitor the communication resources (104, 108) of other communication systems. Communications between communication units in various systems are interchanged through appropriate interaction of the repeaters and the dedicated receivers so provided.

Abstract: A communication resource allocator of a trunking communication system may more efficiently handle service requests during extremely busy times in the following manner. While receiving service requests from communication units, the communication resource allocator determines whether it can process the service request within a predetermined period of time. If the communication resource allocator cannot process the service request within a predetermined period it generates a global system busy which indicates that the communication resource allocator cannot individually process or acknowledge additional service requests. Having generated the global system busy signal, the communication resource allocator transmits it to the plurality of communication units. The communication units process the global system busy signal such that they will not transmit nonpriority service requests during the duration of the global system busy signal.

Abstract: In a trunked communication system that has the capabilities of receiving facsimile transmissions from a communication unit, a method to more efficiently utilize communication resources can be achieved by the following. Once a communication resource allocator has allocated a communication resource to a communication unit for a predetermined period of time, that communication unit transmits at least a portion of a multiple transaction data, which may be a facsimile, to the communication resource allocator. Once the communication resource allocator accurately receives the at least a portion of the multiple transaction data, it transmits an acknowledgement signal to the communication unit. From the acknowledgement signal, the communication unit determines the signal strength of the transmission and also the transmission duration.

Abstract: A method (215) of converting a current control channel for use as a communication (voice/data) channel, in order to maintain a predetermined level of service in a radio communications system, employs a central controller (101) to allocate a limited number of communication channels among a plurality of subscriber units (108-112). After receiving (203) a request for a communication channel from one of a plurality of subscriber units (108-112), the controller (101) determines (205) whether all of the communication channels are busy. The controller then temporarily converts (215) the current control channel to a communication channel.

Abstract: Authentication of system status OSWs in a trunked communication system is provided by first verifying (411) that a received system ID (313) matches a pre-programmed system ID. A system status OSW must then be matched twice before the information in the system status OSW is programmed into a communication unit (115), thus limiting the possibility of false decoding of system status OSWs.

Abstract: In a trunking communication system that is equipped to utilize the control channel as both a voice and control channel, a communication unit can transmit control data to the communication resource allocator in the following manner. Once a voice channel is selected as a voice/control channel, a communication resource allocator transmits the selection to the plurality of communication units. Thus, when the control channel is functioning as a voice channel, the communication unit can transmit a control request to the communication resource allocator via the voice/control channel.

Abstract: In a network of communication systems, control channel traffic can be reduced in a communication system in the following manner. When a source communication unit initiates a communication with at least one target communication unit, that source communication unit generates an individual reference address for the target communication unit and stores that individual reference in an internal data base. Having generated the individual reference address, the source communication unit transmits the reference address to the communication resource allocator of the communication system that it is registered in. The communication resource allocator then determines whether the individual reference of the target communication unit is stored in a reference address data base, located within the communication resource allocator, for the source communication unit.

Abstract: A battery powered TDM (or combined TDM/FDM) communication device (104, 105) operates within a TDM communication system (100) having a communication channel arranged into repetitive time frames (401) each having a plurality of slots. At least two of these slots (404) are allocated for communicating signalling and control information. To conserve energy, the battery powered communication device operates in a first mode (i.e., the energy saving mode) to shut down non-essential circuits for a predetermined time interval, awaking to monitor only one of the two control slots. In this way signalling and control information may be received. When not operating in the energy saving mode, the battery powered communication device operates in a second mode (i.e., a fast access mode) to monitor both of the control slots (404).

Abstract: A communication unit having a dynamic control resource scan list utilizes the scan list to more effectively roam from the current trunked communication system to other trunked communication systems. The scan list contains control resource information of trunked communication systems, where the control resource information is the control resources of the system and the features offered by that system.

Abstract: A method for allocating RF communication resources among RF communication systems. This allocation may be base strictly upon demand or it may be based upon the loading of an RF communication system or the relative loading among a group of RF communication systems.

Abstract: An improved communication system is disclosed wherein at least one reprogramming station is added to a communication system. The reprogramming station is constructed and arranged to communicate with the subscriber units thereby either reprogramming or regrouping them. The subscribing units receive the reprogramming command and acknowledge individually, altering a memory means until either reprogrammed back to the original state, or to another state. In another mode, the reprogramming station transmits a regrouping command wherein two or more groups are combined to form a super group.

Abstract: A trunked communication system utilizes talkgroup synchronization for roaming communication units. By automatically matching the communication unit's talkgroup in a first area-wide system with an talkgroup in a second area-wide system, the communication system facilitates rapid association with a desired talkgroup.

Abstract: An improved communication system is disclosed wherein at least one reprogramming station is added to a communication system. The reprogramming station is constructed and arranged to communicate with the subscriber units thereby either reprogramming or regrouping them. The subscribing units receive the reprogramming command and acknowledge individually, altering a memory means until either reprogrammed back to the original state, or to another state. In another mode, the reprogramming station transmits a regrouping command wherein two or more groups are combined to form a super group.

Abstract: A trunked communication signalling method is provided by a unifying signalling protocol in which subscribers request communication channels using only their individual IDs encoded into a single ISWs. The central decodes the call request, extracts the requesting subscriber's individual ID, which is cross referenced to determine the subscriber's talk-group affiliation(s). If the requesting subscriber's affiliation(s) are not known, the central commands the subscriber to transmit its affiliation using dual ISW signalling. In another aspect of the present invention, each subscriber automatically informs the central of a change in talk-group affiliation, thereby providing continual affiliation updates. In this way, many thousand subscribers are afforded access to a single trunked system, and control channel traffic congestion is minimized.

Abstract: While receiving a lower priority message, a remote transceiver unit in a trunked radio communication system is diverted immediately to a priority channel when a priority message is generated. In a first embodiment, a low speed, sub-audible sync word, transmitted by a system controller, causes the remote transceiver to momentarily interrupt the current message and receive priority data transmitted by the system controller. If the priority level of the priority messages exceeds that of the current message, it immediately switches to the priority channel. If not, the remote transceiver reverts to its normal receiving mode and continues its original communication. In a second embodiment, the priority data is transmitted entirely sub-sudible so as to not interrupt the current message. Lastly, in a more basic embodiment, a sub-audible word is transmitted to the remote units causing them to revert to the control channel to receive the priority call assignment.

Abstract: A console interface for a trunked communication system is disclosed wherein unique interface modules are coupled to the central controller and console network to establish communication therebetween. A console interface constructed and arranged to transceive trunking channel call information couples the dispatcher console to the console network thereby allowing the dispatcher to interact with the trunked system.

Abstract: The system requires the use of the permanent ID of the requesting unit in every channel request made on a control channel before every transmission. The channel grant will include the ID along with the channel number and these may be recorded for possible later reference. A channel assignment is retained for a brief period after each transmission, allowing a conversation to be continued on the same channel without a break. Units can access the control channel with a channel request and be assigned a channel even while the dispatcher is using the voice channel. In the case of a need for communication with a larger group, a dispatcher can form a temporary "patch" group of all involved units, with a temporary ID assigned to that group. A channel request from a member of the larger group must then include, not only the permanent ID of the requesting unit, but the temporary ID of the "patch" group.