Abstract: A method for selecting a channel for group communications in a conventional multi-channel communication system comprises receiving, for a plurality of channels in the multi-channel communication system, a talkgroup assignment list for the channels that identifies a set of talkgroups assigned to use the corresponding channels. A subscriber unit receives talkgroup assignment lists for multiple different channels, determines a desired talkgroup, and selects a channel assigned to the desired talkgroup using the received talkgroup assignment. The talkgroup assignment list is developed for at least one channel in the multi-channel communication system and identifies a set of talkgroups assigned to use the corresponding channel. The list is transmitted for the channel to a subscriber unit and is used by the subscriber unit to register with the system and affiliate with a talkgroup supported by the channel in the conventional multi-channel communication system.

Abstract: A hosted inter-radio frequency subsystem interface (HIF) maintains a list of affiliated radio frequency subsystems (RFSSs), the list identifies at least one serving RFSS. An affiliation request is transmitted from the HIF to the home RFSS, which is a home RFSS of the group. The HIF receives from the serving RFSS a request to initiate an inter-RFSS group call to the group using HIF addressing. The HIF transmits a request to the home RFSS to initiate the inter-RFSS group call using serving RFSS addressing. A data packet from the home RFSS or the serving RFSS is received at the HIF. Upon receipt, the HIF transmits a copy of the data packet to the serving RFSS if the data packet was received from the home RFSS; otherwise, the HIF transmits a copy of the data packet to the home RFSS if the data packet was received from the serving RFSS.

Abstract: A method and device enable establishing an inter-radio frequency subsystem interface (ISSI) unit-to-unit call between a calling unit of a calling home radio frequency subsystem (RFSS), and a called unit of a called home RFSS, through a hosted ISSI function (HIF). The method includes processing, at the HIF, a first invite message received from the calling home RFSS, wherein the first invite message includes a first request uniform resource identifier (URI) that designates an alias system unit identification (SU-ID). In response to the first invite message, transmitting, from the HIF to the called home RFSS, a second invite message, including a second request URI that designates a real SU-ID, wherein the HIF acts as the calling home RFSS. The unit-to-unit call is thus established between the calling unit and the called unit through the calling home RFSS, the HIF, and the called home RFSS.

Abstract: A method for indicating the status of communication channels assigned to a talkgroup includes: determining the channels in various sites in a conventional communication system that service a talkgroup for media transmissions between subscribers of the talkgroup; receiving notification of the status of transmission activity on the channels; and based on the notification, providing an indication of the status of the channels assigned to the talkgroup so that the talkgroup or subscribers of the talkgroup can choose to proceed with a talkgroup communication. The notification may be received by an infrastructure device in an RF site or a central controlling entity. The indication may be that the channel is free for transmissions or is busy.

Abstract: A method and device enable establishing an inter-radio frequency subsystem interface (ISSI) unit-to-unit call between a calling unit of a calling home radio frequency subsystem (RFSS), and a called unit of a called home RFSS, through a hosted ISSI function (HIF). The method includes processing, at the HIF, a first invite message received from the calling home RFSS, wherein the first invite message includes a first request uniform resource identifier (URI) that designates an alias system unit identification (SU-ID). In response to the first invite message, transmitting, from the HIF to the called home RFSS, a second invite message, including a second request URI that designates a real SU-ID, wherein the HIF acts as the calling home RFSS. The unit-to-unit call is thus established between the calling unit and the called unit through the calling home RFSS, the HIF, and the called home RFSS.

Abstract: A hosted inter-radio frequency subsystem interface (HIF) maintains a list of affiliated radio frequency subsystems (RFSSs), the list identifies at least one serving RFSS. An affiliation request is transmitted from the HIF to the home RFSS, which is a home RFSS of the group. The HIF receives from the serving RFSS a request to initiate an inter-RFSS group call to the group using HIF addressing. The HIF transmits a request to the home RFSS to initiate the inter-RFSS group call using serving RFSS addressing. A data packet from the home RFSS or the serving RFSS is received at the HIF. Upon receipt, the HIF transmits a copy of the data packet to the serving RFSS if the data packet was received from the home RFSS; otherwise, the HIF transmits a copy of the data packet to the home RFSS if the data packet was received from the serving RFSS.

Abstract: A method for indicating the status of communication channels assigned to a talkgroup includes: determining the channels in various sites in a conventional communication system that service a talkgroup for media transmissions between subscribers of the talkgroup; receiving notification of the status of transmission activity on the channels; and based on the notification, providing an indication of the status of the channels assigned to the talkgroup so that the talkgroup or subscribers of the talkgroup can choose to proceed with a talkgroup communication. The notification may be received by an infrastructure device in an RF site or a central controlling entity. The indication may be that the channel is free for transmissions or is busy.

Abstract: A method for selecting a channel for group communications in a conventional multi-channel communication system comprises receiving, for a plurality of channels in the multi-channel communication system, a talkgroup assignment list for the channels that identifies a set of talkgroups assigned to use the corresponding channels. A subscriber unit receives talkgroup assignment lists for multiple different channels, determines a desired talkgroup, and selects a channel assigned to the desired talkgroup using the received talkgroup assignment. The talkgroup assignment list is developed for at least one channel in the multi-channel communication system and identifies a set of talkgroups assigned to use the corresponding channel. The list is transmitted for the channel to a subscriber unit and is used by the subscriber unit to register with the system and affiliate with a talkgroup supported by the channel in the conventional multi-channel communication system.

Abstract: A communication control console having both data and voice capability. Data signalling as transmitted on a voice channel is converted into an internally compatible format, regardless of the original signalling type, for use by the console. Conversely, data messages originating from the console are converted from the internal format to the appropriate external signalling format.