Abstract:
There is provided, in a source device, a method for handing off a media session from the source device to a target device in a network. The target device is informed of an impending handoff of the media session. Session state information is transmitted to the target device in preparation for the handoff. The source device is authenticated with respect to a router that is common to both the source device and the target device, prior to the handoff. The conducting of the media session on the source device is ceased in place of the target device, subsequent to the handoff.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention generally relates to networks and, more particularly, to a method and system for handing off a media session across multiple devices in a network environment.  
         [0003]     2. Background of the Invention  
         [0004]     In some circumstances, it would be advantageous for a user to be able to conduct a multimedia session over multiple devices (mobile or fixed). For example, such a capability is particularly useful in a mobile environment where a user can move around while still maintaining multimedia session continuity. Unfortunately, existing solutions only address the problem of maintaining session continuity on a single mobile device across different networks.  
         [0005]     Accordingly, it would be desirable and highly advantageous to have a method and system for handing off a media session across multiple devices in a network environment.  
       SUMMARY OF THE INVENTION  
       [0006]     The problems stated above, as well as other related problems of the prior art, are solved by the present invention, which is directed to a method and system for handing off a media session across multiple devices in a network environment.  
         [0007]     According to an aspect of the present invention, there is provided a method for handing off a media session from a source device to a target device in a network. The target device is informed of an impending handoff of the media session. Session state information is transmitted to the target device in preparation for the handoff. The source device is authenticated, typically via a router that is common to both the source device and the target device, prior to the handoff. The conducting of the media session on the source device is ceased in place of the target device, subsequent to the handoff.  
         [0008]     According to another aspect of the present invention, there is provided, a method for handing off a media session from a source device to the target device in a network. A communication is received of an impending handoff of the media session to the target device. Session state information is received from the source device in preparation for the handoff. The target device is authenticated, typically via a router that is common to both the source device and the target device. The media session is conducted thereon in place of the source device.  
         [0009]     According to yet another aspect of the present invention, there is provided a method for handing off a media session from a source device to a target device in a network. The source device and the target device are authenticated with respect to an impending handoff from the source device to the target device. Session related information is obtained from at least one of the source device and the target device. The session is redirected from the source device to the target device.  
         [0010]     These and other aspects, features and advantages of the present invention will become apparent from the following detailed description of preferred embodiments, which is to be read in connection with the accompanying drawings.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]      FIG. 1  is a diagram illustrating an environment  100  in which the present invention can be employed, according to an illustrative embodiment of the present invention; and  
         [0012]      FIG. 2  is a flow diagram illustrating a method for handing off a media session from a first device to a second device in a network environment, according to an illustrative embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0013]     The present invention is directed to a method and system for handing off a media session across multiple devices in a network environment.  
         [0014]     The present invention allows for seamlessly moving media sessions across multiple devices. Thus, for example, a current video session can be moved from a mobile user&#39;s Personal Digital Assistant (PDA) to single device (e.g., a nearby projector) or to multiple devices that are close to the user while the user moves around.  
         [0015]     Advantageously, to successfully execute such a scheme, the present invention employs an intelligent network to redirect packet flows of the multimedia sessions to the intended devices. The devices across which the sessions are handed over coordinate with each other to transfer session states and seamlessly resume the display of the media stream.  
         [0016]     It is to be appreciated that the present invention can be utilized for single media and multimedia applications. Moreover, it is to be appreciated that the present invention can be utilized with respect to mobile devices, fixed (stationary) devices, or any combination thereof. Further, it is to be appreciated that the present invention can be utilized with respect to wireless devices, wired devices, or any combination thereof.  
         [0017]     It is to be understood that the present invention can be implemented in various forms of hardware, software, firmware, special purpose processors, or a combination thereof. Preferably, the present invention is implemented as a combination of hardware and software. Moreover, the software is preferably implemented as an application program tangibly embodied on a program storage device. The application program can be uploaded to, and executed by, a machine comprising any suitable architecture. Preferably, the machine is implemented on a computer platform having hardware such as one or more central processing units (CPU), a random access memory (RAM), and input/output (I/O) interface(s). The computer platform also includes an operating system and microinstruction code. The various processes and functions described herein can either be part of the microinstruction code or part of the application program (or a combination thereof) that is executed via the operating system. In addition, various other peripheral devices can be connected to the computer platform such as an additional data storage device and a printing device.  
         [0018]     It is to be further understood that, because some of the constituent system components and method steps depicted in the accompanying Figures are preferably implemented in software, the actual connections between the system components (or the process steps) can differ depending upon the manner in which the present invention is programmed. Given the teachings herein, one of ordinary skill in the related art will be able to contemplate these and similar implementations or configurations of the present invention.  
         [0019]     As noted above, the present invention addresses the scenario in which multimedia session continuity is maintained while the session migrates from one device to another. Such a session is most likely, but not necessarily, started from a mobile device and streamed from a server over a network. Such seamless session handover is particularly appealing in a pervasive/ubiquitous computing environment in which mobile users take advantage of devices (wireless or fixed) around them anywhere, any time for the best user experience. Given their intended purposes, mobile handheld devices are generally small in display size, low on processing capacity and limited in battery power. These limitations sometimes restrict the user experience, especially for streaming multimedia applications. To address these limitations, these handheld devices can take advantage of the fixed devices in their vicinity to seamlessly hand off streaming multimedia flow to these fixed devices for processing and display. As an example, consider the scenario where a mobile user with an EDA (Entertainment Digital Assistant) starts a network streaming video session on his/her EDA. When the user moves close to a computer device with a big display (in comparison to the EDA), the session is automatically handed over to the big display with a much higher quality. While the user moves around, the video session can follow the user to different devices and can finally return back to the EDA when the user moves away from the fixed display devices. This results in a better user experience that simply using small handheld devices in a mobile networking environment.  
         [0020]      FIG. 1  is a diagram illustrating an environment  100  in which the present invention can be employed, according to an illustrative embodiment of the present invention. It is presumed that a user currently has a streaming multimedia session being conducted on a device (e.g. an EDA).  
         [0021]     The environment  100  includes an access network  110  having a common router  120  and at least one multimedia server (hereinafter “multimedia server”)  125  therein. An original data flow path  130  is shown from the common router  120  to a first device (also referred to herein as “source device”)  140 . A second device (also referred to herein as “target device”)  150  receives a session state transfer  160 . Accordingly, a redirected flow path  170  is shown from the common router  120  to the target device  150 .  
         [0022]     The source device  140  and the target device  150  each include a transceiver  198  for transmitting and receiving media and other information. The source device  140  and the target device  150  each include a modem  197 . Moreover, the source device  140  and the target device  150  each include a locating device  199  for locating other devices and for being located by other devices. It is to be appreciated that the router  120  also includes a transceiver  198  and a modem  197 .  
         [0023]     It is to be appreciated that the present invention is not limited to the preceding elements and, thus, other elements can also be employed in accordance with the present invention while maintaining the spirit of the present invention. Moreover, it is to be appreciated that the present invention is not limited to the preceding sub-elements (e.g., transceiver  198 , modem  197 , and so forth) and, thus, other sub-elements can also be employed in accordance with the present invention while maintaining the spirit of the present invention.  
         [0024]      FIG. 2  is a flow diagram illustrating a method for handing off a media session from a first device to a second device in a network environment, according to an illustrative embodiment of the present invention.  
         [0025]     The following method describes the steps in seamlessly moving a media session to a different device while maintaining session continuity.  
         [0026]     As used herein, the phrase “source device” refers to a device on which a media session is currently being conducted/hosted, and the phrase “target device” refers to a device to which the current media session is to be handed-over to from the source device. Moreover, the source device receives the media for the media session from one or more multimedia servers (hereinafter “multimedia server”). The source and target devices can be mobile, fixed, or a combination thereof. For illustrative purposes, the source device described in the example of  FIG. 2  is a mobile device.  
         [0027]     A target device  150  is first identified (step  210 ). The identification can be either initiated by the access network  110  or by the source device  140  itself.  
         [0028]     After the network  110  identifies the target device  150 , the network can track the target device  150  using any known technique, apparatus, and/or system including, but not limited to, triangulation techniques, Global Positioning System (GPS), BLUETOOTH, and so forth. The triangulation techniques can be used to determine the target device location by gathering information form three wireless access points. The network  110  also maintains a list of fixed devices that can serve as target devices. The mobile user is notified of the existence of such devices once the network  110  determines that the user is close to one of the fixed devices.  
         [0029]     In the case that the target device  150  is identified by the source device  140  itself, the source device  140  can be equipped with short range locating mechanisms including, but not limited to, a Bluetooth interface. Nearby devices equipped with Bluetooth interfaces can be automatically discovered when the source device moves into the vicinity.  
         [0030]     The source device  140  contacts the target device  150  directly (e.g., through the Bluetooth interface) or through the network  110  regarding a handoff from the source device  140  to the target device  150  (step  220 ).  
         [0031]     The target device  150  performs access control functions in preparation for the handoff from the source device  140  (step  230 ). The access control functions, include, but are not limited to, the following. The target device  150  can determine whether it currently has enough capacity to accommodate the session (e.g., the display is not completely occupied by other sessions). Further, the target device  150  can authenticate the user to make sure that the user has the right to use the target device  150  in the first place. Moreover, the target device  150  can determine whether the user has sufficient credits, if the user needs to pay for the service.  
         [0032]     Session state information is transferred from the source device  140  to the target device  150 , when the source device  140  passes access control (step  240 ). It is to be appreciated that the session state information is application dependent. One example of session state information can include, for example, the destination port number for the session so that the target device  150  can listen for the right session flow. Another example of session state information can include, for example, the multimedia server address and port number. Yet another example of session state information can include, for example, the starting frame sequence number of the session so that the target device  150  can resume the session from the right position. It is to be appreciated that the present invention is not limited to the preceding types of session state information and, thus, other types of session state information, as readily contemplated by one of ordinary skill in the related art given a specified application, can be employed in accordance with the present invention while maintaining the spirit of the present invention.  
         [0033]     The source device  140  and the target device  150  each contact a common router (e.g., router  120 ) of the access network  110  to respectively authenticate themselves (step  250 ). The common router  120  is identified as the first crossover router when, for example, both devices send packets towards the multimedia server  125 .  
         [0034]     If both the source device  140  and the target device  150  are connected to the same sub network, then the router for the sub network is the common router. If the packets sent from both the source device  140  and the target device  150  do not cross over their paths in the access network  110  and the multimedia server  125  is located outside of the access network  110 , then the gateway router to the Internet for the access network  110  is the common router.  
         [0035]     If both the source device  140  and the target device  150  are not in the same network (e.g., the source device  140  is using a Third Generation (3G) cellular interface and the target device  150  is using a dial-up or cable Internet connection), or if the source device  140 , the target device  150  and the multimedia server  125  are in the same sub network, then, in such cases, the router  120  would not be employed. Rather, the multimedia server  125  could, in such cases, perform the functions described herein with respect to the router  120 . Given the preceding configuration examples of the source device  140 , the target device  150 , the multimedia server  125 , and the router  120 , other configurations involving these and related elements can be readily contemplated and implemented with respect to the present invention, while maintaining the spirit of the present invention.  
         [0036]     The common router  120  obtains Session information from at least one of the source device  140  and the target device  150 , once the common router  120  has authenticated both devices at step  250  (step  260 ). Based on the session information, the common router  120  sets up proper packet filtering and redirects the media session from the source device  140  to the target device  150  (step  270 ). For example, the common router  120  can set up packet filtering and perform redirection so that the destination IP address in the incoming packets (to the source device  140 ) for the session is rewritten to the IP address of the target device  150 , and the source IP address in the outgoing packets (from the target device  150 ) for the session is rewritten to the IP address of the source device  140  (so that the multimedia server  125  is unaware that it is no longer communicating with the original device  140  and the session will not be disrupted).  
         [0037]     The target device  150  can negotiate with the multimedia server  125  to upgrade/downgrade the quality of the session (step  280 ), once the session is properly migrated to the target device  150 . For example, when the session is moved from a small mobile device to a big display device, the quality can be significantly upgraded.  
         [0038]     Although the illustrative embodiments have been described herein with reference to the accompanying drawings, it is to be understood that the present invention is not limited to those precise embodiments, and that various other changes and modifications can be affected therein by one of ordinary skill in the related art without departing from the scope or spirit of the invention. All such changes and modifications are intended to be included within the scope of the invention as defined by the appended claims.