EP1550334A1 - Transfert de flux souple - Google Patents

Transfert de flux souple

Info

Publication number
EP1550334A1
EP1550334A1 EP02772698A EP02772698A EP1550334A1 EP 1550334 A1 EP1550334 A1 EP 1550334A1 EP 02772698 A EP02772698 A EP 02772698A EP 02772698 A EP02772698 A EP 02772698A EP 1550334 A1 EP1550334 A1 EP 1550334A1
Authority
EP
European Patent Office
Prior art keywords
data stream
user
server
location
hand over
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP02772698A
Other languages
German (de)
English (en)
Inventor
Anders Norstrom
Kay Johansson
Thomas c/o Gunnilla Bourdette KJELL
Kent Karlsson
Emil Petersson
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Popwire Com
Original Assignee
Popwire Com
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US10/263,486 external-priority patent/US20030078045A1/en
Application filed by Popwire Com filed Critical Popwire Com
Publication of EP1550334A1 publication Critical patent/EP1550334A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L65/00—Network arrangements, protocols or services for supporting real-time applications in data packet communication
    • H04L65/80—Responding to QoS
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/12—Reselecting a serving backbone network switching or routing node
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/0005—Control or signalling for completing the hand-off
    • H04W36/0011—Control or signalling for completing the hand-off for data sessions of end-to-end connection
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W80/00—Wireless network protocols or protocol adaptations to wireless operation
    • H04W80/04—Network layer protocols, e.g. mobile IP [Internet Protocol]

Definitions

  • the present invention relates generally to the mobile telecommunications field; and, more particularly, to a method and apparatus for providing a soft stream hand over in a radio-based wireless telecommunications network
  • relay/cache servers are used at certain nodes in the Radio Network to provide a good Quality of Service (QoS).
  • QoS Quality of Service
  • a similar approach is used on the Internet.
  • a distributed network provides improved QoS because it helps avoid bottlenecks in the infrastructure of the Network.
  • FIGURE 1 is a diagram that schematically illustrates the operation of a distributed network 10 for transmitting a data stream over the Internet.
  • a data stream from a master stream server 12 is transmitted to any or all of a plurality of clients, designated by computers 14, via the Internet, generally designated by reference number 16.
  • the clients 14 may be at different locations, e. g.,
  • each client receives the stream via a relay/cache stream server 18.
  • each client will receive the data stream via the closest relay/cache stream server 18.
  • FIGURE 2 is a diagram that schematically illustrates the operation of a distributed network 20 for transmitting a data stream over a Radio Network.
  • a master relay 22 of a Mobile Switching Center (MSC) 24 sends out a data stream to a plurality of Radio Network Controllers (RNCs) 26 via relay servers 28 associated with each RNC.
  • RNCs Radio Network Controllers
  • a single MSC can control a plurality of RNCs, for example, ten RNCs, and is connected to each RNC with, for example, a 4Mbit fiber.
  • Each RNC is, in turn, connected to a plurality of Base Stations 30 via, for example, a 34Mbit fiber, and a terminal 32, such as a mobile phone, is connected to a base station with up to 384Kbits.
  • a difference between the Internet and a wireless radio-based network is that with the Internet, a client is connected to a fixed point (e. g., to the closest relay/cache server) during a particular session; whereas, in a radio-based network, a client must be able to move freely between relay servers during a session without any interruption of service.
  • a user connects to his Internet Service Provider (ISP) through a modem or a fixed line; and then receives the data stream from the closest relay/cache server. The user will remain connected to the same access point throughout the entire data transfer session.
  • ISP Internet Service Provider
  • a user moves from one location to another, for example, from New York to London, he will simply connect to another ISP in London and again receive the stream from the closest relay/cache server.
  • the Internet when a user moves between locations, he disconnects from the Internet at the old location and then reconnects at the new location.
  • a wireless radio-based network on the other hand, a user connects with his terminal to the nearest Base Station, and if the user moves, there must be a hand over from one Base Station to another. In particular, the user is served by the relay server connected to the nearest Base Station. If the relay server is located at the RNC, it will serve all the Base Stations connected to that RNC.
  • FIGURES 3A and 3B are diagrams that schematically illustrates this procedure.
  • a user 40 is connected to a Base Station 42 which is being served by a relay server 44 to receive a data stream sent out by master relay 46.
  • FIGURE 3B when the user 40 moves from Base
  • the present invention provides a method and apparatus for providing a substantially seamless hand over of a user receiving a data stream when the user moves from a first location served by a first server to a second location served by a second server, and that does not require that the data stream be streamed back through the back-end of a network.
  • a hand over of a user receiving a data stream when the user moves from a first location served by a first server to a second location served by a second server is accomplished by providing the data stream at both the first and second servers, and synchronizing the data streams at the first and second servers to provide a substantially seamless hand over when the user moves from the first location to the second location.
  • the hand over of the user when the user moves from the first location to the second location is controlled by an Application Program Interface (API) .
  • API Application Program Interface
  • the API synchronizes the first and second servers so that they both play the exact time frame of the data stream (and, in fact, so that the data streams are synchronized down to the bit level). Accordingly, when the hand over is made, the user will "see" the data stream in a substantially seamless manner without any interruption.
  • synchronization is accomplished by using a time stamp to calculate and synchronize between the data streams at the first and second servers.
  • a technique is provided to achieve a substantially seamless hand over of a user when the user moves from a first location served by a first server to a second location served by a second server.
  • the invention accomplishes the hand over without having to stream the data through the back-end of a network.
  • FIGURE 1 is a diagram that schematically illustrates the operation of a distributed network for transmitting a data stream over the Internet
  • FIGURE 2 is a diagram that schematically illustrates the operation of a distributed network for transmitting a data stream over a wireless radio-based network
  • FIGURES 3A and 3B are diagrams that schematically illustrate a known procedure for hand over of a user from a first location served by a first relay server to a second location served by a second relay server in a wireless radio-based network;
  • FIGURES 4A-4C are diagrams that schematically illustrate a procedure for a soft stream hand over of a user from a first location served by a first relay server to a second location served by a second relay server in a wireless radio-based network according to an exemplary embodiment of the present invention.
  • FIGURE 5 is a flow chart illustrating a method for a soft stream hand over of a user when the user moves from a first location served by a first relay server to a second location served by a second relay server in a wireless radio-based network according to another exemplary embodiment of the present invention.
  • the present invention makes it possible for a user to receive an uninterrupted data stream when moving from a first location to a second location within a wireless network.
  • the data stream is provided to both the relay server currently serving a user at the first location and to the relay server that will serve the user when the user moves to the second location in the wireless network.
  • the data streams at the two relay servers are synchronized so that the user will begin receiving the stream at the second location at the same point at which he stops receiving the stream at the first location; and, in this way, the user will continue to receive the data stream in a substantially seamless manner when the hand over is made.
  • FIGURES 4A-4C are diagrams that schematically illustrates the manner in which a substantially seamless hand over of a user is accomplished when the user moves within a wireless network according to an exemplary embodiment of the invention.
  • the wireless network is generally designated by reference number 60; and as shown in each of FIGURES 4A-4C, the network includes an Application Program Interface (API) 62 to handle and control a soft stream hand over of a user 70 when the user moves from a first location served by relay server 64 via Base Station 74 to a second location served by relay server 66 via Base Station 76.
  • API Application Program Interface
  • the data stream that is being sent to the user from the first relay server is also provided at the second relay server.
  • This can be accomplished in a variety of ways as is known to those skilled in the art, and, accordingly, is not described herein.
  • the API 62 starts the relay server 66 and synchronizes the playback as indicated by arrow 71 in FIGURE 4B.
  • the new relay server 66 then starts sending the data stream to the user 70 from the point where the old relay server 64 stops sending the data stream to the user (FIGURE 4C).
  • the user 70 will continue to receive the data stream in a seamless manner without any interruption.
  • the hand over should be accomplished at the correct frame. This means, for example, that if user 70 has watched 34 seconds of a particular data stream from the first relay server 64, the hand over should occur exactly 34 seconds into the content that is being received from the second relay server 66.
  • This synchronization is achieved in accordance with an exemplary embodiment of the present invention by utilizing a time stamp that is associated with every packet in the data stream.
  • every bit within a video/audio stream has the same time stamp, and a codec utilizes this information to know which bits should be decoded to put together in a frame.
  • the API 62 synchronizes the two relay servers 64 and 66 down to the bit level so that they both play the exact same frame.
  • the present invention uses the time stamp as a base to calculate and synchronize between the streams.
  • a problem that results when doing this is that the data stream has a random packet numbering.
  • This problem is solved by a procedure developed in connection with synchronizing bit streams when switching between different bit rates in IP stream switching (see commonly assigned copending U. S. Patent Application Serial No. 10/105,526 entitled METHOD AND APPARATUS FOR BROADCASTING STREAMING VIDEO, the disclosure of which is herein incorporated by reference).
  • the two streams are synchronized so that when switching, the packet numbering will be in the right order. This technique works for both live and on-demand data streams.
  • the API In order to operate properly, the API must know when to make the switch from one stream to the other.
  • a 3G/GPRS Radio Network signals when a user moves from one Base Station to another Base Station, and the present invention utilizes this same information and feeds it into the API.
  • the ID of the Base Station In a W-LAN Network, the ID of the Base Station can be used to know "where" in the network it is so as to know which relay server is the closest.
  • the soft stream handover API is an algorithm that synchronizes the IP- stream switching and which has an input to know when and where to switch.
  • FIGURE 5 is a flow chart that illustrates steps of a method for a soft stream handover of a user receiving a data stream from a first relay server to a second relay server in a wireless network according to an exemplary embodiment of the present invention.
  • the method is generally designated by reference number 100, and begins by providing the data stream to both the first and the second relay servers (step 110).
  • the API starts the second relay server (step 130) and synchronizes the first and second relay servers (step 140) so that the second relay server starts sending the data stream to the user at substantially the exact point where the first relay server stops sending the data stream to the user (step 150).
  • the user accordingly, will experience a substantially seamless hand over without it being necessary to send the data stream through the back-end of the Network. While what has been described herein constitutes exemplary embodiments of the present invention, it should be recognized that the invention can be varied in many ways without departing from the scope thereof.
  • a user is described as moving from a first location to a second location in a wireless radio-based network
  • the user can also move between networks.
  • a user could move from an enterprise having an internal network to an external wireless network.
  • a handover is made so that the user is then being served from a server in the external wireless network.
  • his mobile phone works like any PBX-connected phone.
  • the user moves outside the premises, he automatically begins receiving a data stream from a server in the external wireless network.

Abstract

L'invention concerne un procédé et un appareil destinés à produire un transfert sensiblement uniforme d'un utilisateur recevant un flux de données lorsque l'utilisateur se déplace d'un premier emplacement géré par un premier serveur vers un second emplacement géré par un second serveur. Le flux de données est réalisé au niveau du premier et du second serveur, et les flux de données au niveau des premier et second serveurs sont synchronisés de manière que lorsque l'utilisateur se déplace d'un premier emplacement vers un second emplacement, il commence à recevoir le flux de données au niveau du second emplacement sensiblement au même point dans le flux de données auquel l'utilisateur cesse de recevoir le flux de données au niveau du premier emplacement.
EP02772698A 2002-10-02 2002-10-04 Transfert de flux souple Withdrawn EP1550334A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US10/263,486 US20030078045A1 (en) 2001-10-02 2002-10-02 Soft stream hand over
US263486 2002-10-02
PCT/IB2002/004110 WO2004032555A1 (fr) 2002-10-02 2002-10-04 Transfert de flux souple

Publications (1)

Publication Number Publication Date
EP1550334A1 true EP1550334A1 (fr) 2005-07-06

Family

ID=32068279

Family Applications (1)

Application Number Title Priority Date Filing Date
EP02772698A Withdrawn EP1550334A1 (fr) 2002-10-02 2002-10-04 Transfert de flux souple

Country Status (3)

Country Link
EP (1) EP1550334A1 (fr)
AU (1) AU2002337434A1 (fr)
WO (1) WO2004032555A1 (fr)

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20010024430A1 (en) * 1996-11-28 2001-09-27 Kiyoki Sekine Mobile communication system for accomplishing handover with phase difference of frame sync signals corrected

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6085250A (en) * 1997-03-20 2000-07-04 Efficient Networks, Inc. Method and system for using layered networking application program interfaces (APIs) using a native asynchronous transfer mode (ATM) API
JP3529621B2 (ja) * 1997-05-12 2004-05-24 株式会社東芝 ルータ装置、データグラム転送方法及び通信システム
US6230013B1 (en) * 1997-11-26 2001-05-08 Telefonaktiebolaget Lm Ericsson (Publ) Diversity handling moveover for CDMA mobile telecommunications
US6725038B1 (en) * 1999-01-26 2004-04-20 Nokia Corporation Method and apparatus for speeding up AAL2 connection setup during handover in advanced cellular networks
DE19928999C2 (de) * 1999-06-24 2002-12-05 Siemens Ag Verfahren und Einrichtung zum Umschalten (Handover) im Uplink einer Funk-Kommunikationsverbindung

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20010024430A1 (en) * 1996-11-28 2001-09-27 Kiyoki Sekine Mobile communication system for accomplishing handover with phase difference of frame sync signals corrected

Also Published As

Publication number Publication date
WO2004032555A1 (fr) 2004-04-15
AU2002337434A1 (en) 2004-04-23

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