EP1186142A1

EP1186142A1 - Dispatch service to dispatch clients via a packet-switched network

Info

Publication number: EP1186142A1
Application number: EP00916445A
Authority: EP
Inventors: Timothy J. Sherburne
Original assignee: Motorola Inc
Current assignee: Motorola Solutions Inc
Priority date: 1999-05-28
Filing date: 2000-03-16
Publication date: 2002-03-13
Also published as: BR0011018A; EP1186142A4; WO2000074326A1; AR029363A1

Abstract

The present invention addresses the need for providing dispatch service to dispatch clients via a packet-switched network such as the Internet by disclosing a network dispatch manager, a method for a network dispatch manager to provide dispatch service, and a method for a dispatch client to obtain dispatch service. Dispatch service is provided via a multicast capable, packet-switched network (124) connecting a network dispatch manager (101) to dispatch clients (126 and 128). A multicast group is assigned to a dispatch group and used to broadcast packets containing speech information to dispatch clients that are members of that dispatch group. Thus, dispatch service can be provided to dispatch clients in addition to wireless devices (134, 136 and 138).

Description

DISPATCH SERVICE TO DISPATCH CLIENTS VIA A PACKET-SWITCHED NETWORK

Field of the Invention

The present invention relates generally to communication systems and. in particular, to a method and apparatus for providing dispatch service to dispatch clients via a packet-switched network.

Background of the Invention

Wireless communication systems, and specifically wireless dispatch systems, are known. Such wireless dispatch systems provide dispatch services that allow groups of mobile users to communicate spontaneously as a group without the need for arranging a conference call. In today's wireless dispatch systems, each group member must carry a radio-phone device, and remain within the coverage area of the dispatch system to maintain communication with the group.

With the recent proliferation of internet technologies and the ubiquitous nature of internet access today, a great variety of existing technologies are integrating with and exploiting the Internet. Integration of wireless dispatch systems with the Internet, could enable dispatch users to maintain dispatch communication using a computer connected to the Internet, for example, in place of a radio-telephone device that must remain within the coverage area of the dispatch system. Thus, a group of users, some with radio-telephones and others, dispatch clients, with computers connected to the Internet from anywhere in the world, could communicate as a group just as groups of radio-telephone users do today.

Therefore, a need exists for an apparatus and method for providing dispatch service to dispatch clients via a packet-switched network such as the Internet. Brief Description of the Drawings

FIG. 1 is a block diagram depiction of a communication system in accordance with a preferred embodiment of the present invention.

FIG. 2 is a logic flow diagram of steps executed by a network dispatch manager in accordance with a preferred embodiment of the present invention.

FIG. 3 is a logic flow diagram of steps executed by a dispatch client in accordance with a preferred embodiment of the present invention.

Description of a Preferred Embodiment

The present invention addresses the need for providing dispatch service to dispatch clients via a packet-switched network such as the Internet by disclosing a network dispatch manager, a method for a network dispatch manager to provide dispatch service, and a method for a dispatch client to obtain dispatch service. Dispatch service is provided via a multicast capable, packet-switched network connecting a network dispatch manager to dispatch clients. A multicast group is assigned to a dispatch group and used to broadcast packets containing speech information to dispatch clients that are members of that dispatch group.

Thus, dispatch service can be provided to dispatch clients in addition to wireless devices.

The present invention encompasses a method for a network dispatch manager in a communication infrastructure to provide dispatch service to dispatch clients connected to the communication infrastructure via a packet-switched network. The network dispatch manager receives a voice signal corresponding to a dispatch group and determines a multicast group that is assigned to the dispatch group. The network dispatch manager bundles a portion of the voice signal into a packet for transport via a multicast capable, packet-switched network and broadcasts the packet to at least one dispatch client via the multicast capable, packet-switched network using the multicast group.

Additionally, the present invention encompasses a method for a dispatch client to obtain dispatch service from a communication infrastructure, wherein the dispatch client is connected to the communication infrastructure via a multicast capable, packet-switched network. The dispatch client receives via a designated multicast group on the multicast capable, packet-switched network an indication that a dispatch group is active on a multicast group. The dispatch client ^" receives via the multicast group a packet containing voice information corresponding to the dispatch group. Finally, the dispatch client generates a voice signal corresponding to the dispatch group using the packet. Lastly, the present invention encompasses a network dispatch manager apparatus. The network dispatch manager apparatus comprises a wireless communication system interface that receives a voice signal corresponding to a dispatch group. The apparatus further comprises a processor, coupled to the wireless communication system interface, that determines a multicast group that is assigned to the dispatch group and bundles a portion of the voice signal into a packet for transport via a multicast capable, packet-switched network. In addition, the apparatus further comprises a packet-switched network interface, coupled to the processor, that broadcasts the packet to at least one dispatch client via the multicast capable, packet-switched network using the multicast group.

The present invention can be more fully understood with reference to FIGs. 1-3. FIG. 1 is a block diagram depiction of a communication infrastructure in accordance with a preferred embodiment of the present invention. Communication system 100 comprises a plurality of mobile wireless communication units 134, 136, and 138, a plurality of dispatch clients 130 and 132, a packet-switched network 124, and a communication infrastructure. The communication infrastructure comprises a dispatch controller 102, a plurality of base sites 112 and 114, and a network dispatch manager 101. Although only two base sites, three mobile wireless communication units, and two dispatch clients are shown, it is clearly understood that a communication system in accordance with the present invention may comprise any number of dispatch clients and any number of base stations supporting any number of mobile wireless communication units.

Preferably, communication system 100 comprises an "iDEN" communication system, all components of which are commercially available from "MOTOROLA", Inc. of Schaumburg, Illinois. Base sites 112 and 114 preferably comprise "iDEN" Enhanced Base Transceiver System (EBTS) sites, and dispatch controller 102 preferably comprises an

"iDEN" Dispatch Application Processor (DAP), an "iDEN" Metro Packet Switch (MPS), and an "iDEN" Packet Duplicator. Accordingly, mobile wireless communication units 134, 136, and 138 preferably comprise "iDEN" wireless phones. In the preferred embodiment, the packet-switched network 124 is the worldwide Internet and dispatch clients 130 and 132 comprise computer devices such as personal computers that are connected to the Internet while executing a dispatch client application program. A preferred network dispatch manager comprises a computer telephony platform such as that used by the "iDEN" DAP. Such computer telephony platforms comprise conventional circuitry operated and controlled by routinely developed software, such as the circuitry and software used in central processing units and network interface cards (NICs).

In the preferred embodiment, the network dispatch manager 101 interfaces to the dispatch controller 102 via interface 104. Likewise, the base sites 112 and 114 interface to the dispatch controller 102 via interfaces 106 and 108, respectively. Preferably, the interfaces 104, 106, and 108 are logically, if not physically, equivalent although the present invention does not require any equivalence of the interfaces. Base site 112 interfaces with mobile wireless communication unit

134 via air interface 118, and base site 114 interfaces with mobile wireless communication units 136 and 138 via air interfaces 120 and 122, respectively. The air interfaces 118, 120, and 122 are preferably standard "iDEN" air interfaces. In contrast, network dispatch manager 101 preferably interfaces with the Internet via interface 116, and dispatch clients 130 and 132 preferably interface with the Internet via interfaces 126 and 128, respectively

Operation of the preferred network dispatch manager 101 and the preferred dispatch clients 130 and 132, in accordance with the present invention, occurs substantially as follows A wireless communication system interface 109 of the network dispatch manager 101 receives a voice signal corresponding to a dispatch group via interface 104 The voice signal preferably comprises speech encoded using Vector Sum Excited Linear Predicting (VSELP) compression The speech information corresponds to a dispatch group Although the dispatch group may comprise any group of mobile wireless communication units and/or dispatch clients, consider, for the purpose of illustration, that the dispatch group comprises mobile wireless communication unit 134 and dispatch client 130

Preferably, the packet-switched network 124 supports the Internet Group Membership Protocol (IGMP) IGMP provides the ability to broadcast packets to multiple recipients using a single address, called a multicast group address A packet sent using a multicast group address will be routed by a multicast capable network to all destinations registered to that multicast group It is understood that the term "multicast group" is used in the art to refer to both a multicast group address and the group of clients registered using the multicast group address Also while the packet-switched network 124 is preferably the Internet, it is understood that the Internet today does not fully support IGMP, although it is believed that the Internet will fully support IGMP eventually Thus, the packet- switched network 124 preferably comprises only the multicast capable portions of the Internet

When a group dispatch call is established, a processor 110 of the network dispatch manager 101 preferably assigns a multicast group to the dispatch group and stores the assignment The processor 110 also instructs a packet-switched network interface 111 of the network dispatch manager 101 to broadcast information that indicates that the multicast group is currently assigned to the dispatch group using a designated multicast group on the packet-switched network 124. The designated multicast group is preferably registered to by each dispatch client served by the network dispatch manager.

The processor 110 bundles a portion of the voice signal into a packet for transport via the packet-switched network 124. Preferably, a portion of the VSELP information is extracted from the voice signal and used to create an internet protocol (IP) packet. In the preferred embodiment, all of the VSELP information would be packetized as such to form as many IP packets as necessary to convey the voice signal via the packet-switched network 124. In an alternate embodiment, however, the voice signal may be converted to comply with the International Telecommunications Union (ITU) H.323 multimedia standard as it is reformated into IP packets.

Processor 110 of the network dispatch manager 01 determines the multicast group that is assigned to the dispatch group, preferably by retrieving the assignment information stored when the multicast group was assigned to the dispatch group. Processor 110 then instructs the packet-switched network interface 111 to broadcast the packet to at least one dispatch client via the multicast capable, packet-switched network 124 using the multicast group. The packet-switched network interface

111 preferably sends the IP packet to dispatch client 130 using the multicast group address. Thus, a network dispatch manager apparatus provides dispatch service to dispatch clients.

FIG. 2 is a logic flow diagram 200 of steps executed by a network dispatch manager in accordance with a preferred embodiment of the present invention. The logic flow begins (202) when a network dispatch manager in a communication infrastructure receives (204) registration information from a dispatch client. Preferably, the registration information comprises the dispatch group and indicates that the dispatch client is registering with the network dispatch manager as a member of a particular dispatch group. The network dispatch manager, in response to receiving the registration information, registers the dispatch client to the dispatch group with a dispatch controller in the communication infrastructure. The dispatch controller, which preferably performs call processing and dispatch call control functions, is thus notified of the dispatch client's registration to the dispatch group.

In the preferred embodiment, when a dispatch call for the dispatch group is set up, the network dispatch manager assigns (208) a multicast group to the dispatch group. The network dispatch manager then broadcasts (210) information using a designated multicast group, indicating that the dispatch group is active and that the dispatch group is using the multicast group. The network dispatch manager broadcasts the information to the dispatch clients registered to the designated multicast group via a multicast capable, packet-switched network.

The network dispatch manager receives (212) a voice signal corresponding to the dispatch group. The voice signal preferably comprises encoded speech information originating from either a mobile wireless communication unit registered to the dispatch group or from a dispatch client registered to the dispatch group. The network dispatch manager determines (214) the multicast group that is assigned to the dispatch group and bundles (216) a portion of the voice signal into a packet for transport. The network dispatch manager then broadcasts (218) the packet to the dispatch client using the multicast group on the multicast capable, packet-switched network. Preferably, all dispatch clients registered to the dispatch group will receive the contents of the packet via the multicast group on the packet-switched network.

For the purpose of illustration, consider the voice signal, a first voice signal, to have originated from a mobile wireless communication unit. A user of a dispatch client taking part in the dispatch call may wish to speak to the dispatch group. The network dispatch manager, in such a scenario, would receive (220) a dispatch talk request for the dispatch group from such a dispatch client. The network dispatch manager would further receive (222) a voice packet from such a dispatch client via the packet-switched network.

Upon receiving the voice packet, the network dispatch manager generates (223) a second voice signal, from the information contained in the voice packet, for transmission within the communication infrastructure. The second voice signal is then preferably transmitted to the mobile wireless communication units of the dispatch group via communication infrastructure transmitters Also upon receiving the voice packet, the network dispatch manager generates (224) a second voice packet from the voice information contained in the voice packet and broadcasts (226) the second voice packet to the dispatch clients of the dispatch group using the multicast group In the preferred embodiment, therefore, the speech information contained in voice packets received from a dispatch client is forwarded to the other dispatch clients of the dispatch group via the multicast group and routed through the communication infrastructure for transmission to mobile wireless communication units of the dispatch group Thus, the preferred logic flow ends (228)

FIG 3 is a logic flow diagram 300 of steps executed by a dispatch client in accordance with a preferred embodiment of the present invention The logic flow begins (302) when the dispatch client receives (304) via a designated multicast group an indication that a dispatch group is active on a multicast group Upon receiving the indication, the dispatch client preferably registers to receive the multicast group messaging and receives (306) via the multicast group a packet containing voice information corresponding to the dispatch group Using the packet, the dispatch client then generates (308) a voice signal corresponding to the dispatch group

Preferably, the packet comprises VSELP information that is extracted to form the voice signal, wherein the voice signal comprises VSELP encoded speech information that is converted to audio in substantially the same manner that mobile wireless communication units convert VSELP encoded speech information to audio today Thus, a user of the dispatch client is able to listen to the audio of the dispatch group as a user of a mobile wireless communication unit of the dispatch group does Alternatively, the packet may comprise speech information encoded according other voice/multimedia standards such as the ITU

H 323 multimedia standard

If the user of the dispatch client wishes to speak to the dispatch group, the dispatch client preferably transmits (310) a dispatch talk request for the dispatch group to the communication infrastructure via the multicast capable, packet-switched network Preferably upon receiving a grant for the dispatch talk request, the dispatch client bundles (312) a portion of a second voice signal, generated from audio received by the dispatch client, into a second packet for transport via the multicast capable, packet-switched network Preferably the second voice signal comprises VSELP encoded speech information that is used to create the second packet according to the internet protocol As noted above the second voice signal may alternatively be converted to comply with the International Telecommunications Union (ITU) H 323 multimedia standard as it is reformated into IP packets

Finally, the dispatch ciient transmits (314) the second packet to the communication infrastructure and the logic flow ends (316)

Thus, dispatch clients and/or mobile wireless communication units are able to take part in dispatch communication as a dispatch group with the present invention Today dispatch communication between mobile wireless communication units is common, but limited Such communication is limited by location constraints, i e mobile wireless communication units must remain within the wireless coverage area of a dispatch system, and limited to dispatch communication with other mobile wireless communication unit users Dispatch clients, in contrast, can be located anywhere where multicast capable network access is available Also since a dispatch client may be run on a laptop computer, for example, a user need not necessarily have both a computer and a mobile wireless communication unit Thus, the present invention expands the accessibility of dispatch communication service to networked computers

The descriptions of the invention, the specific details, and the drawings mentioned above, are not meant to limit the scope of the present invention It is the intent of the inventors that various modifications can be made to the present invention without varying from the spirit and scope of the invention, and it is intended that all such modifications come within the scope of the following claims and their equivalents

What is claimed is

Claims

1 A method for a network dispatch manager in a communication infrastructure to provide dispatch service to dispatch clients connected to the communication infrastructure via a packet-switched network the method comprising the steps of receiving a voice signal corresponding to a dispatch group, determining a multicast group that is assigned to the dispatch group, bundling a portion of the voice signal into a packet for transport via a multicast capable, packet-switched network, and broadcasting the packet to at least one dispatch client via the multicast capable, packet-switched network using the multicast group

2 The method of claim 1 , further comprising the step of assigning the multicast group to the dispatch group

3 The method of claim 1 , further comprising the step of receiving a voice packet from a dispatch client, of the at least one dispatch client, via the multicast capable, packet-switched network

4 The method of claim 3, further comprising the step of generating a second voice signal, from information contained in the voice packet, for transmission within the communication infrastructure

5 The method of claim 4, wherein the step of generating the second voice signal comprises the step of generating the second voice signal for transmission to a mobile wireless communication unit from a communication infrastructure transmitter

6 The method of claim 5, further comprising the steps of generating a second voice packet from voice information contained in the voice packet, and broadcasting the second voice packet to at least one dispatch client via the multicast capable, packet-switched network using the multicast group.

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7 A method for a dispatch client to obtain dispatch service from a communication infrastructure, wherein the dispatch client is connected to the communication infrastructure via a multicast capable, packet-switched network, the method comprising the steps of receiving via a designated multicast group on the multicast capable, packet-switched network an indication that a dispatch group is active on a multicast group, receiving via the multicast group a packet containing voice information corresponding to the dispatch group, and generating a voice signal corresponding to the dispatch group using the packet

8 The method of claim 7, further comprising the steps of transmitting a dispatch talk request for the dispatch group to the communication infrastructure via the multicast capable, packet-switched network, bundling a portion of a second voice signal into a second packet for transport via the multicast capable, packet-switched network, and transmitting the second packet to the communication infrastructure via the multicast capable, packet-switched network

326

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9 A network dispatch manager comprising a wireless communication system interface that receives a voice signal corresponding to a dispatch group, a processor, coupled to the wireless communication system interface, that determines a multicast group that is assigned to the dispatch group and bundles a portion of the voice signal into a packet for transport via a multicast capable, packet-switched network, and a packet-switched network interface, coupled to the processor, that broadcasts the packet to at least one dispatch client via the multicast capable, packet-switched network using the multicast group

10 The network dispatch manager of claim 9, wherein the processor further instructs the packet-switched network interface to broadcast information, using a designated multicast group on the multicast capable, packet-switched network, that indicates that the multicast group is currently assigned to the dispatch group