METHOD AND SYSTEM FOR OPTIMIZNG QUALITY OF SERVICE (QoS) IN

A COMMUNICATION NETWORK

FIELD OF THE INVENTION

[0001] The invention generally relates to Quality of Service (QoS) in a communication network. More specifically, the invention relates to optimizing QoS of a multimedia session between two or more communication devices in a communication network.

BACKGROUND OF THE INVENTION

[0002] Today, the requirement for next-generation, service-capable communication networks are driven by applications, specific Quality of Service (QoS) requirements per application and a need to manage sessions with one or more clients. Various methods are available for delivering multimedia data between communication devices in a communication network. These methods employ different techniques to monitor quality of service (QoS) of the multimedia data for assuring an efficient transmission of multimedia data during a multimedia session.

[0003] In the present scenario, a typical approach for delivering multimedia data to communication devices over a communication network is by employing client-server architecture. A communication device can be for example, but is not limited to, a personal computer, a voice over internet protocol (VoIP) phone, a video phone, a cell phone and a Personal Digital Assistant (PDA). In client-server architecture, a multimedia session between one or more communication devices is facilitated by a central server. When one or more communication devices are involved in the multimedia session, multimedia data such as Audio/Video data may be transmitted from the central server to one or more communication devices. Gradually, when the central server receives requests for multimedia sessions from an increasing number of communication devices, the communication network may experience congestion. This results in lower quality of service of the ongoing multimedia session.

[0004] Another approach of delivering multimedia data over the communication network is by employing a peer-to-peer architecture. For example, in a peer-to-peer architecture, transmission of the multimedia data along with quality feedback packets is carried out amongst one or more communication devices during a multimedia session. The quality feedback packets provide information about QoS pertaining to the multimedia session. Further, a central server controls the multimedia session between one or more communication devices through a control signaling protocol. Since the central server is devoid of the QoS information pertaining to one or more communication devices, the central server is unable to control the quality of the multimedia session.

[0005] There is therefore a need for a method and system for providing efficient monitoring and optimization of QoS of multimedia data in various communication network architectures.

BRIEF DESCRIPTION OF THE FIGURES

[0006] The accompanying figures where like reference numerals referring to identical or functionally similar elements throughout the separate views and which together with the detailed description below are incorporated in and form part of the specification, serve to further illustrate various embodiments and to explain various principles and advantages all in accordance with the invention.

[0007] FIG. 1 is a block diagram showing an environment in which various embodiments of the invention can function.

[0008] FIG. 2 is a block diagram showing a system for optimizing QoS in a communication network in accordance with an embodiment of the invention.

[0009] FIG. 3 is a flowchart of a method for optimizing QoS in a communication network in accordance with an embodiment of the invention.

[0010] FlG. 4 is a flow diagram illustrating an exemplary method for optimizing QoS in a communication network in accordance with an embodiment of the invention.

[0011] Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale.

DETAILED DESCRIPTION

[0012] Before describing in detail the embodiments that are in accordance with the invention, it should be observed that the embodiments reside primarily in combinations of method steps and system components related to method and system for optimizing

Quality of Service (QoS) of a multimedia session in a communication network.

Accordingly, the system components and method steps have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.

[0013] In this document, relational terms such as first and second, top and bottom, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. The terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises ...a" does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.

[0014] Various embodiments of the invention provide method and system for optimizing QoS of a multimedia session between two or more communication devices in a

communication network. The system and method of the invention involve a quality manager for receiving one or more messages corresponding to quality status of the multimedia session between two or more communication devices. The quality manager analyses one or more messages based on one or more predefined QoS criteria. Thereafter, one or more corrective actions corresponding to the multimedia session are derived by the quality manager. In response to the step of deriving one or more correction actions, a session controller performs one or more corrective actions in the multimedia session.

[0015] Referring to the drawings and in particular to FIG. 1, a block diagram showing an environment 100 in which various embodiments of the invention can function.

Environment 100 includes a communication server 102 interfacing with a communication network 104 for communication with one or more communication devices 106-n. As depicted in FIG. 1, one or more communication devices 106-n includes a communication device 106-1 and a communication device 106-2.

[0016] Communication server 102 enables interactive or non-interactive multimedia sessions between two or more communication devices 106-n. Examples of communication server 102 include, but are not limited to, Voice over Internet Protocol (VoIP) server, Multimedia server, Surveillance server, Conference server, and Media gateway. Communication server 102 interfaces with communication network 104 by using one or more communication protocols. Examples of one or more communication protocols include but are not limited to, network protocols such as Internet protocol (IP), transport protocols such as transmission control protocol (TCP), and user datagram protocol (UDP), and application protocols such as session initiation protocol (SIP), H.323, real-time transport protocol (RTP), and real time streaming protocol (RTSP).

[0017] Communication network 104 provides connectivity to one or more communication devices 106-n and communication server 102. Various examples of communication network 104 include, but are not limited to, Internet, wide area network (WAN), local area network (LAN), integrated services digital network (ISDN), Broadband network, wireless interoperability microwave access (WiMAX)

communication network, 3rd generation partnership project (3GPP), universal mobile telecommunication systems (UMTS) and ultra mobile broadband (UMB) network. Communication network 104 supports transmission of multimedia data, for example, but not limited to, audio, video, and textual data amongst two or more communication devices 106-n and communication server 102. Dynamic transmission of the multimedia data between two or more communication devices 106-n results in a multimedia session.

[0018] Communication device 106-n is a computing device capable of exchanging the multimedia data through communication network 104. Communication device 106-n can be for example, but is not limited to, a personal computer (PC), a cellular phone, a laptop, a VOIP phone, a video phone, and a Personal Digital Assistant (PDA). Communication device 106-n is connected to communication network 104 through various technologies such as universal serial bus (USB) Port, global system for mobile communication (GSM), code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), wide area network (WAN), local area network (LAN), wireless interoperability microwave access (WiMAX), universal mobile telecommunication systems (UMTS), or general packet radio service (GPRS). Two or more communication devices 106-n may be connected in various architectures, such as peer to peer architecture (P2P) or client-server architecture.

[0019] Turning now to FIG. 2, a block diagram showing a system 200 for optimizing QoS of a multimedia session in communication network 104 in accordance with an embodiment of the invention. System 200 is connected to one or more communication devices 106-n through communication network 104. According to an embodiment of the invention, system 200 is located at communication server 102. Those skilled in art will recognize that system 200 can be located at any other entity present in environment 100. System 200 includes a session controller 202 and a quality management module 204.

[0020] Session controller 202 is configured to establish a multimedia session between two or more communication devices 106-n. In an embodiment of the invention, communication device 106-1 sends a request for initiating the multimedia session with

communication device 106-2 to session controller 202. Session controller 202 then sends an invite to communication device 106-2. Communication device 106-2 then acknowledges the invite to session controller 202. Session controller 202 then establishes a point to point multimedia session between communication device 106-1 and communication device 106-2. In an exemplary embodiment of the invention, session initiation protocol (SIP) is used for establishing the multimedia session between communication device 106-1 and communication device 106-2. It will be apparent to a person skilled in the art that session controller 202 may employ other protocols for establishing communication between communication devices 106-n.

[0021] Thereafter, transmission of one or more quality status messages is performed by two or more communication devices 106-n by using quality management module 204. Quality management module 204 is configured to manage QoS of the communication occurring through communication network 104. Quality management module 204 receives one or more quality status messages from one or more communication devices 106-n. One or more quality status messages may be received periodically by quality management module 204 from one or more communication devices 106-n.

[0022] In an embodiment of the invention, one or more quality status messages are transmitted to quality management module 204 using real-time transfer control protocol (RTCP) stream. One or more communication devices 106-n are configured to utilize the RTCP stream for transmitting one or more quality status messages to quality management module 204. One or more communication devices 106-n may utilize a hardware or software module for performing such transmission.

[0023] One or more quality status messages provide information about the QoS of an ongoing communication between two or more communication devices 106-n. One or more quality status messages include information about the status of one or more attributes of the multimedia session. One or more attributes of the multimedia session are the parameters controlling the transmission of multimedia data during the multimedia session. Examples of one or more attributes include, but are not limited to, bandwidth,

audio / video codec, video resolution, frame per packet, frame per second, bytes sent, packets sent, packet loss, jitter, and round trip delay of the multimedia session between two or more communication devices 106-n.

[0024] On receiving one or more quality status messages, quality management module 204 analyses one or more quality status messages based on one or more predefined QoS requirements. One or more predefined QoS requirements are one or more conditions for a desired QoS of the multimedia session between two or more communication devices 106- n. One or more conditions correspond to required threshold values of one or more attributes of the multimedia session. For example, if threshold value corresponding to packet loss is 10%, then corresponding predefined QoS requirement is that the packet loss of the multimedia session should remain lower than 10%. Quality management module 204 compares the information received in one or more quality status message with one or more predefined QoS requirements to identify the QoS of the multimedia session.

[0025] Based on the analysis of one or more quality status message, quality management module 204 derives one or more corrective actions corresponding to one or more attributes of the multimedia session. One or more corrective actions may require modification of one or more attributes according to the analysis of one or more quality status messages. Modification of one or more attributes may lead to optimization of QoS in the multimedia session.

[0026] In response to one more corrective actions derived by quality management module 204, session controller 202 performs one or more corrective actions. In an embodiment of the invention, session controller 202 receives one or more corrective actions and implements one or more corrective actions in the multimedia session. In another embodiment of the invention, session controller 202 directs one or more communication devices 106-n to execute one or more corrective actions.

[0027] In an exemplary embodiment, one or more corrective actions include changing of codec for the multimedia session. Session controller 202 sends a direction to communication device 106-1 and communication device 106-2 to change the codec for the multimedia session. In response to receiving the direction, communication device 106-1 and communication device 106-2 change the codec of the multimedia session for optimizing the QoS of the multimedia session.

[0028] In another exemplary embodiment, one or more corrective actions include a change of the communication path of the multimedia session between communication device 106-1 and communication device 106-2, Session controller 202 executes the corrective action by identifying a new communication path for the multimedia session between communication device 106-1 and communication device 106-2. Session controller 202 may utilize a media server for establishing the new communication path between communication device 106-1 and communication device 106-2. If more than one communication paths are available, session controller 202 selects the most optimized new communication path. Thereafter, session controller 202 sends an invite to communication device 106-1 and communication device 106-2 for changing the communication path. In response, communication device 106-1 and communication device 106-2 switch to the new communication path without disrupting the multimedia session ongoing between them.

[0029] FIG. 3 is a flow diagram of a method for optimizing QoS of a multimedia session in communication network 104 in accordance with an embodiment of the present invention is illustrated. The multimedia session is a dynamic transmission of multimedia data between two or more communication devices 106-n. The multimedia session is established by session controller 202. In an exemplary embodiment of the invention, Session controller 202 uses Session Initiation Protocol (SIP) for this purpose. Session controller 202 may associate additional details in SIP for providing information to one or more communication devices 106-n. The additional details may include location information of quality management module 204.

[0030] After establishment of the multimedia session, at step 302, one or more quality status messages of the multimedia session are received by quality management module 204. One or more quality status messages sent by one or more communication devices 106-n provide information about the QoS of the multimedia session. In an embodiment of the invention, one or more communication devices 106-n are configured to utilize the RTCP stream for sending one or more quality status messages to quality management module 204.

[0031] In an embodiment of the invention, one or more quality status messages are received by quality management module 204 periodically. Session controller 202 specifies one or more intervals of time to one or more communication devices 106-n for providing one or more quality status messages. In one aspect, the session controller 202 may specify one or more intervals of time to one or more communication devices 106-n while establishing the multimedia session using SIP. Information regarding one more intervals of time may be included in the additional details associated with SIP. In another aspect, one or more communication devices 106-n may also specify one or more intervals of time for sending one or more quality status messages. In case the specified one or more intervals of time for two or more communication devices 106-n involved in the multimedia session are different, quality management module 204 may synchronize one or more quality status messages according to one or more intervals of time.

[0032] On receiving one or more quality status messages, analysis of one or more quality status messages is performed at Step 304. Quality management module 204 analyzes one or more quality status messages on the basis of one or more predefined QoS requirements. One or more predefined QoS requirements are one or more conditions for a desired QoS of the multimedia session between two or more communication devices 106- n. One or more quality status messages include information about the status of one or more attributes of the multimedia session. For analysis of one or more quality status messages, the status of one or more attributes is compared with one or more predefined QoS requirements.

[0033] On the basis of the analysis of one or more quality status message, one or more corrective actions are derived for the multimedia session at Step 306. Quality management module 204 derives one or more corrective actions corresponding to one or more attributes of the multimedia session. One or more corrective actions may require modification of one or more attributes for optimization of QoS in the multimedia session.

[0034] In an embodiment, if quality management module 204 does not receive one or more quality status messages from two or more communication devices 106-n in a predefined time interval, quality management module 204 assumes the multimedia session as a faulty multimedia session. Thereafter, quality management module 204, directs session controller 202 to terminate the multimedia session.

[0035] As an example of the above step, if according to the analysis of quality management module 204, bandwidth available during a multimedia session between communication device 106-1 and communication device 106-2, is less than a required bandwidth according to the predefined QoS requirements, then quality management module 204 derives a corrective action of changing codec of communication device 106- 1 and communication device 106-2 to a more compressed codec which consumes less bandwidth.

[0036] As another example of the above step, if according to the analysis of quality management module 204, packet loss in a multimedia session between communication device 106-1 and communication device 106-2 is more than permitted packet loss limit according to the predefined QoS requirements, then quality management module 204 derives corrective actions for lowering bandwidth and frame rate of communication device 106-1 and communication device 106-2 to an appropriate level for reducing the packet loss in the multimedia session..

[0037] As yet another example of the above step, if according to analysis of quality management module 204, packet loss is high in a multimedia session between communication device 106-1 and communication device 106-2 and there is congestion in

communication network 104, then quality management module 204 derives a corrective action for changing communication path of multimedia session between communication device 106-1 and communication device 106-2.

[0038] The derived one or more corrective actions are then performed at step 308, by session controller 202. Session controller 202 receives and implements one or more corrective actions in the multimedia session. In an embodiment of the invention, one or more corrective actions are directed by session controller 202 to one or more communication devices 106-n. One or more communication devices 106-n execute one or more corrective actions and optimize the QoS of the multimedia session. In another embodiment of the invention, one or more corrective actions are executed by session controller 202 and are implemented in the multimedia session for optimizing QoS.

[0039] FIG. 4 is a flowchart illustrating an exemplary method for optimizing QoS in a communication network 104 in accordance with an embodiment of the invention. At 402, a session initiation invite is sent by communication device 106-1 to session controller 202. The session initiation invite contains reference information of communication device 106-2 and a request for a video call session. Session controller 202 relays the session initiation invite to communication device 106-2 at 404. Communication device 106-2 accepts the session initiation invite by acknowledging to session controller 202 at 406. Session controller 202 forwards the confirmation of communication device 106-2 to communication device 106-1 at 408. Thereafter, session controller 202 establishes the video call session between communication device 106-1 and communication device 106- 2 at 410. Session initiation protocol (SIP) is used for initiating and establishing the video call session. Further, session description protocol (SDP) is used for specifying standard values of one or more attributes of video call session. One or more attributes of the video call session are frames per second, resolution, codec, compression quality, bandwidth and audio quality. Communication device 106-1 and communication device 106-2 exchange audio and video data of the video call session by using real-time transport protocol (RTP) packet stream.

[0040] Further, communication device 106-1 transmits one or more quality status messages to quality management module 204 using real-time transfer control protocol (RTCP) packet stream at 412. Similarly, communication device 106-2 transmits one or more quality status messages to quality management module 204 at 414. One or more quality status messages are sent to quality management module 204 in periodic interval of time. One or more quality status messages include information about status of one or more attributes of the video call session in a particular interval of time.

[0041] A quality status message sent by communication device 106-1 includes information about actual bandwidth used for the video call session. Similarly, a quality status message sent by communication device 106-2 includes information about packet loss in the video call session. Quality management module 204 analyses one or more quality status messages on the basis of one or more QoS requirements. The quality status messages are analyzed by quality management module 204 by comparing with one or more predefined QoS requirements. Quality management module 204 determines that less bandwidth is available at communication device 106-1 and packet loss is more at communication device 106-2. Thereafter, quality management module 204 derives one or more corrective actions for one or more attributes of the video call session. One of the corrective actions is to reduce current frames per second to an optimum level of the video call session. Another, corrective action is to decrease the current bandwidth used in the video call session to an optimum level.

[0042] Thereafter, session controller 202 receives the two corrective actions from quality management module 204 at 416. Session controller 202 sends directions to communication device 106-1 and communication device 106-2 at 418 and 420. Session controller 202 directs communication device 106-1 and communication device 106-2 to reduce the current frames per second to an optimum level. Further, session controller 202 directs communication device 106-1 and communication device 106-2 to decrease the current bandwidth to an optimum level. As the corrective actions are implemented by communication device 106-1 and communication device 106-2, QoS of the ongoing

video call session is optimized. Therefore, the video call session is continued with better quality at 422.

[0043] Various embodiments of the invention provide method and system for optimizing QoS of a multimedia session between one or more communication devices in a communication network. The method and system of the invention provide dynamic optimization of QoS of the ongoing multimedia session. Hence, quality of the multimedia session is improved without disrupting the multimedia session. The method of the invention involves analysis of one or more quality status messages at a communication server for optimizing QoS of the multimedia session, therefore multimedia data associated with the multimedia session need not be exchanged with the communication server. This results in reduction of load and bandwidth at the communication server. Therefore, the communication server becomes capable of handling more multimedia sessions simultaneously. Hence, congestion in the communication network may be reduced. Further, the invention provides a method and system for performing collective analysis of one or more quality status messages received from one or more communication devices. Hence, comparative actions are derived for one or more communication devices. This provides effective optimization of QoS in the multimedia session.

[0044] In the foregoing specification, specific embodiments of the present invention have been described. However, one of ordinary skill in the art appreciates that various modifications and changes can be made without departing from the scope of the present invention as set forth in the claims below. Accordingly, the specification and figures are to be regarded in an illustrative rather than a restrictive sense, and all such modifications are intended to be included within the scope of the present invention. The benefits, advantages, solutions to problems, and any element(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as a critical, required, or essential features or elements of any or all the claims. The present invention is defined solely by the appended claims including any amendments made during the pendency of this application and all equivalents of those claims as issued.