Abstract: A wireless communication system 200 comprises a connectionless packet network 201 coupled to a plurality of sites 203–208. Upon a first communication unit (213) initiating a call request for a 2-party call with a second communication unit (215), a call server 235 identifies respective multicast IP addresses (MC1, MC2) associated with the source and target. If the first communication unit 213, or its associated site (205) desires to send payload to the second communication unit 215, it addresses the payload to the multicast IP address (MC2) of the second communication unit, and the second communication unit 215, or its associated site 206 joins the multicast address MC2 to receive the payload.

Abstract: A wireless communication system 200 comprises a connectionless packet network 201 coupled to a plurality of sites 203-208. Upon a first communication unit (213) initiating a call request for a 2-party call with a second communication unit (215), a call server 235 identifies respective multicast IP addresses (MC1, MC2) associated with the source and target. If the first communication unit 213, or its associated site (205) desires to send payload to the second communication unit 215, it addresses the payload to the multicast IP address (MC2) of the second communication unit, and the second communication unit 215, or its associated site 206 joins the multicast address MC2 to receive the payload.

Abstract: A method and apparatus for utilizing a distributed location register (20 or 22) within a wireless communication system (10) is accomplished by a distributed location register which receives a request for updating communication parameters of a particular communication entity, which may be a communication device, group of communication devices, or grouping of groups of communication devices, or for retrieval of communication parameters of the particular communication entity. To process the request, the distributed location register (20 or 22) interprets it to identify one of a plurality of communication service registers (28-32, 102-112, or 136-140) which stores the communication entity's communication parameters. Having identified a particular communication service register, the communication service register receives, and subsequently processes, the request to retrieve the communication parameters of interest and/or update the communication parameters of interest.

Abstract: A method and apparatus for utilizing a distributed location register (20 or 22) within a wireless communication system (10) is accomplished by a distributed location register which receives a request for updating communication parameters of a particular communication entity, which may be a communication device, group of communication devices, or grouping of groups of communication devices, or for retrieval of communication parameters of the particular communication entity. To process the request, the distributed location register (20 or 22) interprets it to identify one of a plurality of communication service registers (28-32, 102-112, or 136-140) which stores the communication entity's communication parameters. Having identified a particular communication service register, the communication service register receives, and subsequently processes, the request to retrieve the communication parameters of interest and/or update the communication parameters of interest.

Abstract: A mobility processor (34) provides location update parameters to a subscriber unit (SU1-4). The location update parameters indicate conditions upon which the subscriber unit is to provide its location information to the mobility processor. From the location information, the mobility processor determines whether the subscriber unit has provided the location information in a manner that is consistent with the location update parameters. If the mobility processor determines that the subscriber unit did not provide the location information in a manner that is consistent with the location update parameters, the mobility processor generates a new set of location update parameters which are provided to the subscriber unit.

Abstract: A radio communication system (100, 200) employs a method of providing communication services to a communication unit (104, 105) having a plurality of service requirements. The radio communication system (100, 200) further includes a plurality of service providers (101-103) for which the communication unit catalogues (506, 512) service attributes as part of the inventive method. Further, for each of the service requirements, the communication unit (104, 105) selects (514) one of the plurality of service providers (101-103) to facilitate that service requirement.

Abstract: To set-up a dispatch call, a controller identifies the destination units, destination sites, controlled devices and paths needed to support the call, and which LAN bridges will be used to create the communication paths. The controller then assigns the controlled devices a temporary address identical to the permanent address of one of the controlled devices, and then informs the LAN bridges which LAN ports should carry messages containing the temporary address. With all controlled devices having the same temporary address, and with the LAN bridges ready to pass messages containing the temporary address along a chosen path, the controlled device assigned to support the call request can transmit the messages generated by a source communication unit to other controlled devices using the temporary address. Thus, only one representation of a message produced by the source communication unit is transmitted from the assigned controlled device.

Abstract: In a multi-site communication system, a communication may be handed off from a first site to a second site in the following manner. Upon request and when a communication resource is available, a communication resource allocator allocates the communication resource to the requesting communication unit located in the first site. The communication resource allocator also identifies a reserved communication resource in each adjacent site to the first site. When the communication unit relocates to the second site of the adjacent sites, the communication resource allocator allocates the reserved communication resource of the second site to the communication unit without a request from the communication unit.

Abstract: A communication unit that is registered in a trunked communication system can continue to receive a communication from a first communication unit after initiating a push-to-talk request while the first communication unit is transmitting voice data in the following manner. Having allocated a communication resource to a group of communication units and while processing a request to communicate for the first communication unit, a communication resource allocator receives a request to communicate from a second communication unit to produce a new request to communicate. The communication resource allocator stores the new request to communicate and transmits a response to the second communication unit such that the second communication unit can continue to receive the remainder of the communication from the first communication unit.

Abstract: Resource controllers (14) within a multisite communication system (20) selectively and automatically assume primary (45) and secondary (53) control modes of operation in order to ensure that adequate communication resources are assigned throughout the system at necessary sites in order to include talk group members that are dispersed throughout the system.

Abstract: In a multi-site trunked communication system, a method for allowing a communication unit to place a unit directed group call consists of identifying, by the unit initiating the communication, a target unit and transmitting identification information of the target unit and a group call request to a communication resource allocator. Upon receipt of the identification information and the group call request, the communication resource allocator processes the request and when a resource is available in the site that the target unit is located in, allocates the resource such that the target unit and any other units of the communication group in the site can participate in the group call.

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: In a communication system, a communication unit may conserve source energy when it is inactive in the following manner. The control channel is partitioned into a predetermined number of windows and a system window which are transmitted on the control channel in a round robin manner. When the communication unit registers with the communication system, it is assigned to a window group. The communication unit then monitors only the system window to determine whether the window group that its been assigned to is also assigned to one of the predetermined number of windows. When the window that has been assigned to the window group is being transmitted on the control channel, the communication unit activates to monitor that window. Once the window is no longer being transmitted, the communication unit deactivates until the system window is being transmitted or the window assigned to the window group is being transmitted.

Abstract: Requesting (transmitting) subscriber units may immediately begin transmitting an information signal over an assigned communication channel. Receiving subscriber units immediately unmute their speakers and monitor the assigned communication channel and attempt to detect a code, which indicates that they are monitoring the correct communication channel. At the central station (repeater), the information signal may be immediately repeated, unless an interference signal is present. In this way, the information signal may be rapidly disseminated (repeated) to improve subscriber access time, while providing assurance that the receiving subscribers will not receive a noise signal or the interference signal.

Abstract: A method is employed by a central controller of a radio communications system, which method provides for sustaining a predetermined level of communication service. The system includes a plurality of voice channels which are allocated among a plurality of subscribers (108-112) using a first control channel (102). In a preferred embodiment, at least one of the voice channels (104, 106) is also control-capable. The method includes evaluating (502) a current loading condition, and comparing (504) this loading condition with an upper loading threshold. Where appropriate, the controller assigns (506) one of the control-capable voice channels as a temporary control channel.

Abstract: A radio communication system (200) having a communication site (203) provides communication services to a coverage area (201) surrounding the communication site (203). A plurality of service resources are allocated (318) among a plurality of communication units (205) located within the coverage area (201). A method of responding to a service request transmitted from a requesting communication unit includes the steps of determining (310) a nominal service duration, and estimating (312) an available site time value. A completion probability value can then be calculated (403) using these parameters. The completetion probability value is then used to determine (405-413) whether or not to allocate, to the requesting communication unit, a service resource corresponding to the requested service.

Abstract: A method of tracking subscribers (201, 203) in a networked radio communications system (100, 200). The subscribers (201,203) are able to roam among a plurality of coverage areas (104-106) which are serviced by a plurality of transmitters (107-109). The transmitters (107-109) are coupled to a central processor (CP, 110), which accesses a memory device (112) for storing subscriber records and site records. Subscriber records include location information for each of the subscribers, while the site records include a logical representation of geographical relationships between the coverage areas. The method relies on the subscriber to send an inbound message (330) which includes its current location. Further, the CP (110) records a message time for the inbound message, producing a timestamped location, then updates (405) a corresponding portion of the subscriber record with the timestamped location.

Abstract: In a trunked communication system that supports roaming communication units, communication capabilities in support of the communication activities of the communication unit may be varied from system to system in a controlled manner. This control may be initiated at the instance of the communication unit itself, on a system by system basis (wherein each system maintains a data base and/or retains the capability of contacting a home system for the communication unit), or by a hub that interconnects with each of the trunking systems and which either maintains a data base of preauthorization information or that contacts home systems in order to obtain authorization information.

Abstract: In a network of communication systems, a communication resource allocator of any of the communication systems may reclaim system resources from inactive communication systems. This may be accomplished by having the communication resource allocator transmit at least one polling message to the communication unit to determine whether the communication unit is in need of the at least one system resource. If the communication unit does not respond to the polling message, the communication resource allocator determines whether the communication unit is inactive. If the communication unit is inactive, the communication resource allocator reclaims the at least one system resource from the communication unit.

Abstract: A communication unit within a trunked communication system can reduce control channel traffic by maintaining a data base of the communication system services that it can perform. The data base is maintained by the communication unit selecting a service that it desires to perform. Having selected the service, the communication unit verifies that it is one of the services that it can perform and transmits a request to perform that service to a communication resource allocator. The communication resource allocator responds to the request and the communication unit updates its data base based upon the response from the communication resource allocator. The response transmitted by the communication resource allocator may comprise either a grant to the communication unit that allows it to perform the selected service or a denial that the selected service is one that the communication unit is not allowed to perform.