Abstract: Methods are described that enable host devices of a multicast IP network to reliably join multicast group address(es) in talkgroup or point-to-point calls. For a talkgroup call, a sourcing host sends “hello” packets or payload to one or more network devices, addressed to a multicast group address. The receiving host issues a join command to the one or more network devices in an attempt to reliably join the multicast group address. If any packets are received by the receiving host within a designated time period associated with the attempt, the receiving host is reliably joined to the multicast group address. For a point-to-point call, a controller sends a pair of multicast group addresses, one designated for sourcing packets and the other designated for receiving packets, to a first and second host participating in the point-to-point call. The designated “source” and “receive” multicast group address are complementary for the first and second hosts.

Abstract: A packet switched communications system (100) for use with a dynamic voice jitter buffer (203) and voice over Internet protocol (VoIP) packets includes a source (101) transmitting at least one VoIP packet, one or more routers (105, 107, 109) for routing the VoIP packets and a destination (111) for receiving the at least one VoIP packet. The VoIP packet operates to convey congestion information regarding the packet switched communications system (100) to at least one buffer located at the destination to dynamically control the capacity of the jitter buffer located at the destination to provide VoIP communication with no jitter and minimal delay.

Abstract: Methods for reserving call units of bandwidth and for using the reserved call units to manage call requests are disclosed. Reservations are requested by a first host device (e.g., zone controller) for a path of a packet network communication system. The reservations are granted or denied by the network based on the availability of the requested bandwidth. Once a reservation has been obtained, the number of call units of bandwidth associated with the reservation may be reduced or increased by the network based, for example, on link failures, repairs, etc. Call requests are granted or denied by the zone controller based on the path(s) needed for the call, the number of reserved call units associated with the path(s) and the amount of call units required to support the call. If there are sufficient reserved call units to support the call, the call may proceed by sending, from a second host device (e.g., repeater), a message that is distributed over the number of units of bandwidth needed for the call.

Abstract: Methods for reserving call units of bandwidth and for using the reserved call units to manage call requests are disclosed. Reservations are requested by a first host device (e.g., zone controller) for a path of a packet network communication system. The reservations are granted or denied by the network based on the availability of the requested bandwidth. Once a reservation has been obtained, the number of call units of bandwidth associated with the reservation may be reduced or increased by the network based, for example, on link failures, repairs, etc. Call requests are granted or denied by the zone controller based on the path(s) needed for the call, the number of reserved call units associated with the path(s) and the amount of call units required to support the call. If there are sufficient reserved call units to support the call, the call may proceed by sending, from a second host device (e.g., repeater), a message that is distributed over the number of units of bandwidth needed for the call.

Abstract: Methods are described that enable host devices of a multicast IP network to reliably join multicast group address(es) in talkgroup or point-to-point calls. For a talkgroup call, a sourcing host sends “hello” packets or payload to one or more network devices, addressed to a multicast group address. The receiving host issues a join command to the one or more network devices in an attempt to reliably join the multicast group address. If any packets are received by the receiving host within a designated time period associated with the attempt, the receiving host is reliably joined to the multicast group address. For a point-to-point call, a controller sends a pair of multicast group addresses, one designated for sourcing packets and the other designated for receiving packets, to a first and second host participating in the point-to-point call. The designated “source” and “receive” multicast group address are complementary for the first and second hosts.

Abstract: The present invention encompasses a method of facilitating an audio source change in a digital radio communication system (100). A typical system includes a plurality of audio source units ( 101-103), a plurality of audio destination units (105, 106), and a switching unit (108) for rendering one of the plurality of audio source units (101-103) operable. Upon receipt (302) of an information-bearing frame from an audio source unit, a frame sequence value is identified (304). The expected frame sequence value is then determined (306), and this value is compared to the identified frame sequence value to determine whether or not the received frame sequence value matches the expected frame sequence value. When the frame sequence values match, it is assumed that the frames were sourced from the same audio source unit (i.e., no source change has occurred).

Abstract: A method at comparator (103) of determining the depth of remote buffer (107-109), by computing the difference between the current time and a next launch time, where the next launch time is the time at which a next information packet will be transmitted by the base station (104-106) on the radio channel. The next launch time is determined by the summation of, the time to transmit a previous information packet with error correcting information on the radio channel, and the launch time of a previous information packet. The method further includes maintaining the buffer depth between thresholds such that information packets will not be provided beyond a maximum threshold and filler packets will be provided when buffer depth is less than a minimum threshold.