Patent Application
20090047938
1. Technical Field
The present invention relates generally to a media handling system. In particular, the present invention relates to an apparatus for controlling media handling in a multimedia conference between participants in a cellular network and participants in a mobile ad-hoc network.
2. Background
Although multi-hop wireless networks have been the subject of study for decades, attention has more recently turned to so-called Multihop Cellular Networks. Multihop Cellular Networks result from the linking of multihop mobile ad-hoc network models to conventional single-hop cellular networks, such as those conforming to specifications developed by the 3rd Generation Partnership Project (3GPP). These hybrid networks offer enhanced flexibility and greater communications power compared to either network standing alone. However, linking these networks also raises new challenges for the seamless deployment of advanced multimedia applications.
Multimedia conferencing is just one important category of these advanced applications. Multimedia conferencing includes audio and video conferencing as well as multiparty gaming and scores of other interactive multimedia applications involving several users.
Multimedia conferencing generally consists of two distinct sub-sessions—call signaling and media handling. Call signaling includes the establishment, modification and tear down of call sessions, while media handling in conferences includes the setting up, controlling, and tearing down of media connections between participants, and the management of media components. Those media components include key components such as mixers, which receive media streams from multiple sources, combine them, and send the mixed streams to the participants. Other media components include bridges, gateways, controllers, transcoders, and so on.
In 3rd-generation (3G) networks standardized by 3GPP, media handling functions are centralized in a system component called the Multimedia Resource Function (MRF), pictured in
The 3GPP MRF pictured in
In contrast to the centralized media handling in multimedia conferences on 3G networks, media handling in mobile ad-hoc networks (MANETs) is often distributed. Because there is generally no fixed infrastructure in a MANET, control functions and media processing functions are distributed among the MANET mobile user nodes.
An exemplary architecture for distributed media handling in a MANET multimedia conference is illustrated in
As was shown in
Because control elements are generally distributed in a mobile ad-hoc network, while centralized in conventional cellular networks, media handling architectures will differ between the two. These differences are demonstrated in the exemplary architectures depicted in
Various systems and apparatus for controlling media handling in a multimedia conference between participants in a cellular network and participants in a mobile ad-hoc wireless network (MANET) are disclosed. Among the cellular networks that may be supported by these systems are 3rd-generation cellular networks, such as those defined by the 3rd-Generation Partnership Project (3GPP).
One such apparatus is a multimedia conference mediator, comprising a first interfacing unit for communicating with a media gateway controller in the MANET, a second interfacing unit for communicating with a media resource controller in a centralized media resource unit in the cellular network, and a mediator core connected to each of the interfacing units and configured to establish a media-bearing connection between a media mixer function in the MANET and a media resource processor controlled by the media resource controller, using the media gateway controller and the media resource controller. The first and second interfacing units are configured to provide interfaces compatible with a MANET media gateway controller interface and a media control interface in the media resource controller, respectively.
Thus, from the MANET point of view, the media resource controller in the cellular network is made to appear as a MANET media gateway controller. Similarly, the MANET media gateway controller is made to appear to the media resource controller as a peer media resource controller. In one or more embodiments of the invention, the mediator core includes a protocol translator operative to translate first messages received from the MANET media gateway controller to second messages for the media resource controller in the centralized media resource unit.
In some embodiments of the invention, the multimedia conference mediator further comprises a conference gateway interface for communicating with a conference gateway controller. The mediator core establishes the media-bearing connection between the MANET media mixer and the media resource processor in the cellular network in response to one more multimedia session primitives received from the conference gateway controller.
Certain embodiments of the multimedia conference mediator comprise a media connection mediator, under the control of the mediator core, which is operative to receive multimedia traffic from the MANET media mixer function and from the media resource processor in the cellular network, and to translate between media streaming protocols used in the respective networks.
A media resource system for controlling media handling in a conference between at least one mobile terminal in a cellular network and a plurality of mobile user nodes in a MANET comprises a media resource processor configured to mix incoming media streams from the mobile terminal and a MANET media mixer, a media resource controller for controlling media stream resources within the media resource processor, a MANET interfacing unit for communicating with a media gateway controller in the MANET, and a mediator core connected to the MANET interfacing unit and configured to establish a media-bearing connection between the MANET media mixer function and the media resource processor, using the media resource controller and the media gateway controller. The MANET interfacing unit is configured to provide an interface compatible with a MANET media gateway controller interface.
An ad-hoc multimedia mediator node for controlling media handling in a conference between at least one mobile terminal in a cellular network and a plurality of mobile user nodes in a MANET comprises a MANET media mixer configured to mix incoming media streams from the mobile user nodes and a media stream from a media resource processor associated with the mobile terminal in the cellular network, a media gateway controller configured to control the MANET media mixer, a cellular network interfacing unit for communicating with a media resource controller in a centralized media switching unit in the cellular network, and a mediator core connected to the cellular network interfacing unit and configured to establish a media-bearing connection between the MANET media mixer and the media resource processor, using the media gateway controller and the media resource controller.
Of course, the present invention is not limited to the above features and advantages. Indeed, those skilled in the art will recognize additional features and advantages upon reading the following detailed description, and upon viewing the accompanying drawings.
It should be understood that the following description, while indicating several embodiments of the invention, is given by way of illustration only. Various changes and modifications within the scope of the invention will become apparent to those skilled in the art. Furthermore, although the below discussion focuses on 3GPP networks and one or more possible mobile ad-hoc network architectures, those skilled in the art will recognize that the principles and devices described herein are readily applicable to a variety of cellular and mobile ad-hoc networks and network architectures.
As discussed above, the linking of a mobile ad-hoc network (MANET) with a 3G cellular network creates challenges for the implementation of multimedia conferencing applications involving participants from both networks.
Using the methods and apparatus described herein, a MANET and a cellular network may be linked for purposes of multimedia conferencing, with minimal changes to either. Thus, from the MANET point of view, media resource controller 430 and media resource processor 440, components of the media resource function 420 in the 3G cellular network, are made to appear as MANET media gateway controllers and MANET media mixers, respectively. Similarly, using the approaches described herein, MANET media gateway controller 220 and MANET media mixer 230 appear as a peer media resource controller and peer media resource processor, respectively.
Media resource controllers 115 and media resource processors 120 used in conventional 3G cellular networks do not currently have interfaces with peer entities. Accordingly, as will be described in detail below, the 3GPP MRF is modified to provide a signaling link 450 between media resource controller 430 and multimedia conference mediator 410. This modification includes the extension of MRF protocols to facilitate peer-to-peer communication between one MRF and another; these same extended protocols are used for communication between media resource controller 430 and multimedia conference mediator 410. In particular, the protocol utilized between the MRFC and the MRFP is extended to support these new interfaces. Likewise, media resource processor 440 is provided with a new interface to permit a media-bearing connection 460 to media mixer 230.
These additional interfaces may be designed to permit the decentralization of conferencing in 3G cellular networks, facilitating conferencing with several media resource controllers 430 and several media resource processors 440 residing in one or more 3G cellular networks. Today, conferences may already be conducted with participants connected to more than one 3G cellular network. However, without these additional interfaces, all participants must establish connections to the same media resource function 420. As a result, media handling performance is limited by the resources of that single media resource 420, and will degrade as additional users join. Thus, these additional interfaces improve scalability. Furthermore, these additional interfaces permit interfacing with other types of networks as well as with media resource functions 420 in other 3G cellular networks.
As illustrated in
The protocol for the Mc interface between media resource controller peers may comply with the Megaco/H.248 protocol, using the same vocabulary and concepts that are currently used with Megaco/H.248, but extended to define messages between media resource controller peers rather than just between a controller and a mixer. For example, when a media resource controller 430 must make a media connection between its media resource processor 440 and a target media resource process 440 associated with a second media resource controller 430, it simply sends an “Add” command to the second media resource controller 430, which in turn commands the targeted media resource processor 440 to add the media connection. Reply messages are exchanged to finalize the operation.
The Mm interface permits two media resource processor peers to provide resources for the media connections between them. This interface also permits a media resource processor peer to connect to one or more media mixers 230 in a MANET, as well. In any event, this interface is used for media stream transport between media resource processor peers, using, for example, Real-time Transport Protocol (RTP) packets. Therefore, in decentralized environments, i.e. those employing more than one media resource processor 440, the media mixing operation is different than that deployed on conventional 3GCNs.
One example of how the mixing operation is performed can be described as follows: Suppose that users X and Y send media streams to a first media resource processor (MRP-1) and users U and V send media streams to a second (MRP-2). MRP-1 immediately mixes the streams from U and V and sends the result to MRP-2. MRP-2 in turn does the same thing with its entries from X and Y. When receiving the mixed result, MRP-2 performs a first mix by mixing the entry from MRP-1 with the stream of U and sends the result to V, and does a second mix by mixing the entry from MRP-1 with the stream of V and sends the result to U. MRP-1 performs the same process with its users. Thus, media streams received from a peer media resource processor, through interface Mm, are handled just as media streams from directly-connected UEs 125 are processed, even though the former may be previously mixed streams.
These new interfaces are also used to link the 3G cellular network's media resource function 420 with one or more MANET nodes 210, as shown in
The mediator core 530 is required only when a multimedia conference includes users in both the 3G cellular network and the MANET. It is seen by MANET entities as a MANET media gateway controller 220 that controls media mixing functionality associated with conference participants in the 3G cellular network. Accordingly, it has all the capabilities of a MANET media gateway controller 220, and can control connectivity to media resource processors 440 in the 3G cellular network, which appear to the MANET as additional MANET media mixers 230.
From the point of view of the media resource function 420 in the 3G cellular network, on the other hand, the mediator core 530 entity is perceived by media resource controller 430 as a peer media resource controller, with which it can communicate using the Mc reference point. Thus, multimedia conference mediator 410 assures the independence of the 3G cellular network from the topologies and protocols used in the MANET.
If the 3G media resource processor 440 and the MANET media mixer 230 use different media streaming protocols, then media connection mediator 540 is used to translate between those protocols. Media connection mediator 540 may also be used when other media processing should be done when interfacing with between the 3G cellular network and the MANET. If media connection mediator 540 is used, then media bearing connections from MANET media mixer 230 and media resource processor 440 are routed to media connection mediator 540 using the MANET interfacing unit 510 and the cellular network interfacing unit 520, respectively.
The interface between mediator core 530 and media connection mediator 540 may be identical to that deployed between a media gateway controller 220 and a media mixer 230 in the MANET. In particular, this interface may employ the Megaco/H.248 protocol. When media processing is required at multimedia conference mediator 410, the mediator core 530 enables the media connection mediator 540 and sets up the necessary media connections to media resource processor 440 in the 3G cellular network and to the MANET media mixer 230, using the media gateway controller 230 in the MANET and the media resource controller 430 in the cellular network.
Use of the multimedia conference mediator 410 as described herein does not limit the topology of the MANET. In particular, media gateway controllers 220 and MANET media mixers 230 may still be connected to each other using a full mesh structure as earlier described. Indeed, media resources in both the 3G cellular network and the MANET can be configured using a variety of structures, such as hierarchies or trees.
Setting up call sessions between conference participants in the 3G cellular network and the MANET requires a call signaling system. Referring back to the exemplary configuration of
The conference gateway 470 may also provide publication and discovery services for the mobile user nodes 210 and/or the mobile conference applications 240 in the MANET. Thus configured, it periodically sends service advertisements to all nodes. A node that requires a particular service sends a discovery message through the network and waits for a response. Finally, conference gateway 470 also provides registration functions and manages the repository of MANET users.
Once call signaling has been established between users in the two networks, conference gateway 470 must discover a media gateway controller to make the necessary media connections. The discovery functionality consists of the ability to find a suitable media gateway controller 220 or multimedia conference mediator 410 that can connect the joining participant. In the embodiment illustrated in
Referring once more to
Using the components and systems described herein, a user in either of the MANET or cellular networks may initiate a multimedia conference. Four scenarios are possible for starting a conference involving participants in both networks: a cellular network user initiates the conference with a MANET user, a MANET user initiates the conference with a cellular network user, a cellular network user invites a MANET user to a pre-existing cellular network multimedia conference, and a MANET user invites a cellular network user to a pre-existing conference.
In
It should be noted that the above description of a multimedia conference initiation assumes that the media mixer function 230 at MANET-User is able to establish a media connection directly to media resource processor 440. As discussed above, if different media transport protocols are used, then the media connection will instead be routed through a media connection mediator 540 at the multimedia conference mediator 410 for translation or transcoding.
Once a multimedia conference is established between cellular network users and MANET users, additional users can be invited. A cellular network user that wishes to invite a MAN ET user first establishes call signaling to it. In response, the media resource controller 430 is triggered to add the MANET user.
Those skilled in the art will appreciate that the conference initiation and invitation procedures described above are merely exemplary, and that various modifications and extensions of these procedures are possible. Those skilled in the art will also recognize that the functional components of the multimedia conference mediator 410 described herein may be deployed in a number of different configurations, depending on the network structures, operator business models, and other factors.
One such configuration is depicted in
Another configuration is depicted in
Ad-hoc multimedia mediator node 900 also comprises a mediator core 950 and media connection mediator 960. These provide the same control, translation, and processing functions earlier described. Finally, ad-hoc multimedia mediator node 900 comprises a cellular network interface 970, facilitating connections to one or more media resource controllers 430 and media resource processors 440 in a cellular network.
The multimedia mediator node 900 thus allows the multimedia conference mediator functionality to be deployed at a node in the MANET. The mediator functionality may be enabled when a conference between 3G and MANET participants is first established, or when a participant from the other network is first invited to a one-network multimedia conference. Those skilled in the art will appreciate that the same mechanisms used to enable and disable new media gateway controllers and media mixers in the MANET may also be employed to enable and disable the multimedia mediator functions of mediator core 950 and media connection mediator 960.
Those skilled in the art will immediately appreciate that all of the functional units described herein, including the mediator core 530, media connection mediator 540, MANET interfacing unit 510, cellular network interfacing unit 520, media resource controller 430, media resource processor 440, media mixer 230, and media gateway control 220, may be implemented by computer program instructions and/or hardware operations. The same, of course, applies to the illustrated variants of these functional blocks, including MANET interface 810, mediator core 820, media connection 830, media resource controller 840, media resource processor 850, mediator core 950, media connection mediator 960, and cellular network interface 970. These computer program instructions may be provided to a processor of a general purpose computer, a special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions described herein and illustrated in the accompanying block diagrams and flow diagrams.
These computer program instructions may also be stored in a computer usable or computer-readable memory that may direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer usable or computer-readable memory produce an article of manufacture including instructions that implement the functions described herein. Several of the functional entities described herein may be implemented together on a single processor or computer, or each may be implemented on separate processors or computers. Those skilled in the art will recognize the advantages and disadvantages of grouping or distributing the functions described herein.
With these and other variations and extensions in mind, those skilled in the art will appreciate that the foregoing description and the accompanying drawings represent non-limiting examples of the systems and apparatus taught herein for controlling media handling in a conference between participants in a cellular network and a mobile ad-hoc network. As such, the present invention is not limited by the foregoing description and accompanying drawings. Instead, the present invention is limited only by the following claims and their legal equivalents.
