Method for flow control, node and communication network employing the flow control

• US 6,192,039 B1
• Filed: 03/19/1997
• Issued: 02/20/2001
• Est. Priority Date: 03/25/1996
• Status: Expired due to Fees

• Current Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Original Assignee: YRP Mobile Telecommunications Key Technology Research Laboratories Company Limited
• Inventors: Tanaka, Motoharu, Shinagawa, Noriteru, Nishio, Masaya, Watanabe, Yoneo
• Primary Examiner(s): Olms, Douglas
• Assistant Examiner(s): VANDERPUYE, KENNETH N
• Application Number:
  US08/820,607
• Time in Patent Office: 1,434 Days
• Field of Search: 470/331, 470/230, 470/235, 470/338, 470/401, 470/428, 470/429, 455/436, 455/437, 455/438, 455/439, 455/440, 455/441, 455/442, 455/443, 455/412, 455/415
• US Class Current: 370/331
• CPC Class Codes: H04L 2012/5607 Radio
• CPC Class Codes: H04L 2012/563 Signalling, e.g. protocols, reference model
• CPC Class Codes: H04L 2012/5632 Bandwidth allocation
• CPC Class Codes: H04L 2012/5636 Monitoring or policing, e.g. compliance with allocated rate, corrective actions
• CPC Class Codes: H04L 2012/5652 Cell construction, e.g. including header, packetisation, depacketisation, assembly, reassembly
• CPC Class Codes: H04L 2012/5681 Buffer or queue management
• CPC Class Codes: H04L 49/254 Centralised controller, i.e. arbitration or scheduling
• CPC Class Codes: H04L 49/30 Peripheral units, e.g. input or output ports
• CPC Class Codes: H04L 49/3009 Header conversion, routing tables or routing tags
• CPC Class Codes: H04L 49/3081 ATM peripheral units, e.g. policing, insertion or extraction
• CPC Class Codes: H04L 49/50 Overload detection or protection within a single switching element
• CPC Class Codes: H04W 36/02 Buffering or recovering information during reselection ; Modification of the traffic flow during hand-off

Abstract

There is provided a method for a flow control to a mobile communication network in which an ATM virtual channel established between a first base station having a radio zone in which a mobile station exists and a terminating ATM node to which a remote station with which the mobile station communicates is connected. The first step of the method is to queue, in an ATM node, incoming cells to be sent to a second base station having a radio zone when the mobile station is handed over to the radio zone of the second base station. The second step of the method is to stop queuing and send the incoming cells queued in the ATM node to the second base station after the mobile station is handed over.

Claims

1. A method for a flow control to a mobile communication network in which an ATM virtual channel established between a first base station having a radio zone in which a mobile station exists and a terminating ATM node to which a remote station with which the mobile station communicates is connected, said method comprising the steps of:

(a) sending hand-over start information to an ATM node accommodating the first base station therefrom when, the mobile station moves to a radio zone covered by a second base station;

(b) recognizing, in an ATM node in which the ATM virtual channel between the mobile station and the remote station is formed even after a hand-over, an ATM transmission path and an ATM virtual channel directed to the second base station;

(c) queuing, in the ATM node, incoming cells to be transferred via the recognized ATM transmission path;

(d) sending hand-over end information to the ATM node from the second base station when the hand-over is completed;

(e) recognizing, from the hand-over end information, the ATM transmission path and the ATM virtual channel directed to the second base station;

(f) stopping queuing at the step (c) and outputting the incoming cells queued to the second base station via the recognized ATM transmission path.

2. The method as claimed in claim 1, further comprising the steps of transferring the hand-over start information and the hand-over end information over the ATM transmission path between the first and second base stations and the terminating ATM node so that ATM nodes located in the ATM transmission path receive the hand-over start information and the hand-over end information, whereby the ATM nodes queue cells directed to the second base station in a distributed formation.

3. The method as claimed in claim 1, wherein the step (c) queues the incoming cells in a buffer provided to an input ATM transmission path connected to an upper ATM node.

4. A method for a flow control to a mobile communication network having a hierarchical structure formed by base stations, ATM nodes directly connected thereto and other ATM nodes, wherein a mobile station located in a radio zone of a first base station communicates with a remote station via an ATM virtual channel formed therebetween, said method comprising the steps of:

(a) sending hand-over start information from the first base station to an ATM node accommodating the first base station when the mobile station moves to a second radio zone accommodated in a second base station, the hand-over start information concerning the second base station and an ATM virtual channel established for the mobile station;

(b) recognizing, from the hand-over start information, an ATM transmission path and an ATM virtual channel directed to the second base station;

(c) queuing, in an upper ATM node located at a hierarchical level higher than the first and second base stations, incoming cells to be transferred via the recognized ATM transmission path;

(d) sending hand-over end information to the upper ATM node from the second base station when the hand-over is completed, said hand-over end information including information concerning the second base station and an ATM virtual channel newly established for the mobile station which is handed over thereto;

(e) recognizing, in the upper ATM node, the ATM transmission path and the ATM virtual channel directed to the second base station from the hand-over end information;

(f) stopping queuing at the step (c) and outputting the incoming cells queued to the second base station via the recognized ATM transmission path.

5. The method as claimed in claim 4, further comprising the step of transferring the hand-over start information and the hand-over end information over the ATM transmission path between the first and second base stations and the terminating ATM node so that ATM nodes located in the ATM transmission path receive the hand-over start information and the hand-over end information, whereby the ATM nodes queue cells directed to the second base station in a distributed formation.

6. The method as claimed in claim 4, wherein the step (c) queues the incoming cells in a buffer provided to an input ATM transmission path connected to an ATM node located at a higher hierarchical level.

7. A method for a flow control to a communication network in which cells are transferred via a virtual channel established between nodes, said method comprising:

(a) temporarily storing incoming cells transferred over an input transmission path in a first buffer in a node in which the virtual channel is switched;

(b) re-routing the virtual channel to another route;

(c) allocating a transmission band of an output virtual channel in an output transmission path in order to send the cells stored in the first buffer thereto at a bit rate higher than that of an input virtual channel thereof and to thus facilitate sending the cells which are stored in the first buffer during a hand-over,

(d) sending the cells stored in the first buffer to the output transmission path; and

(e) releasing the transmission band allocated to send the cells stored in the first buffer.

8. The method as claimed in claim 7, wherein:

the output transmission path is normally allocated so as to have a normal band and a margin band; and

the step (c) allocates the transmission band so as to include a part of the normal band and a part of the margin band.

9. The method as claimed in claim 7, wherein the step (a) comprises the step of storing the incoming cells in the first buffer via a cell switch of the node so that the input virtual channel via which the incoming cells are transferred is connected to the first buffer.

10. The method as claimed in claim 9, further comprising the steps of:

temporarily storing further incoming cells in a second buffer provided between the input transmission path and the cell switch;

disconnecting the input virtual channel from the first buffer and connecting it to the output virtual channel;

allocating a transmission band in the output transmission path in order to send the cells stored in the second buffer thereto at a bit rate higher than that of the input virtual channel thereof;

sending the cells in the second buffer to the output transmission path; and

releasing the transmission band allocated to send the cells stored in the second buffer.

11. A node in a communication network in which cells are transferred via a virtual channel established between nodes, said node comprising:

a cell switch; and

a buffering terminal,

said buffering terminal comprising;

a buffer temporarily storing incoming cells transferred over an input transmission path; and

a cell sending part allocating a transmission band of an output virtual channel in an output transmission path in order to send the cells stored in the buffer thereto at a bit rate higher than that of an input virtual channel thereof and to thus facilitate sending the cells which are stored in the first buffer during a hand-over, and sending the cells stored in the buffer to the output transmission path.

12. A communication network in which cells are transferred via a virtual channel established between nodes, each of said nodes comprising:

a cell switch; and

a buffering terminal,

said buffering terminal comprising;

a buffer temporarily storing incoming cells transferred over an input transmission path; and

a cell sending part allocating a transmission band of an output virtual channel in an output transmission path in order to send the cells stored in the buffer thereto at a bit rate higher than that of an input virtual channel thereof and to thus facilitate sending the cells which are stored in the first buffer during a hand-over, and sending the cells stored in the buffer to the output transmission path.

13. A method for flow control to a mobile communication network in which cells are transferred via a virtual channel established between a base station having a radio zone in which a mobile station exists and a node in which a remote terminal with which the mobile station communicates is accommodated, said method comprising:

(a) temporarily storing incoming cells transferred over an input transmission path in a first buffer in the node in which the virtual channel is switched in response to movement of the mobile station of a radio zone of another base station;

(b) rerouting the virtual channel to another route;

(c) allocating a transmission band of an output virtual channel in an output transmission path in order to send the cells stored in the first buffer thereto at a bit rate higher than that of an input virtual channel thereof;

(d) sending the cells stored in the first buffer to the output transmission path; and

(e) releasing the transmission band allocated to send the cells stored in the first buffer.

14. A mobile communication network in which cells are transferred via a virtual channel established between a base station having a radio zone in which a mobile station exists and a node in which a remote terminal with which the mobile station communicates is accommodated, comprising:

a cell switch; and

a buffering terminal,

said buffering terminal comprising;

a buffer temporarily storing incoming cells transferred over an input transmission path; and

a cell sending part allocating a transmission band of an output virtual channel in an output transmission path in order to send the cells stored in the buffer thereto at a bit rate higher than that of an input virtual channel thereof, and sending the cells stored in the buffer to the output transmission path,

the buffering terminal operating when the virtual channel is switched due to movement of the mobile station to a radio zone of another base station.