Bandwidth variable communication method, bandwidth variable communication apparatus, transmission bandwidth determination apparatus, transmission bandwidth determination method, node apparatus, communication path setting system, communication path setting

Patent metadata

Field	Value
Publication number	US-8964581-B2
Application number	US-201013395747-A
Country	US
Kind code	B2
Filing date	Sep 13, 2010
Priority date	Sep 14, 2009
Publication date	Feb 24, 2015
Grant date	Feb 24, 2015

Abstract

A bandwidth variable communication method is provided that enables effective use of frequency bandwidths in which the bit rate is constant in every optical path. The bandwidth variable communication method includes, when a network management apparatus sets or changes an optical path that passes through plural communication apparatuses, measuring or obtaining an optical signal quality deterioration amount in a route of the optical path; selecting a modulation format in which a spectrum bandwidth is the narrowest from among modulation formats by which transmission is available on conditions of the optical signal quality deterioration amount and a desired bit rate B (bit/s); and exchanging control information between the network management apparatus and a control unit of each communication apparatus on the optical path route. A bandwidth variable communication apparatus receives the control information, and changes a passband based on the received control information.

First claim

The invention claimed is:

1. A bandwidth variable communication method in an optical path network, in which communication apparatuses are connected by optical transmission, that includes a network management apparatus having a function for setting and managing an optical path,
the method being performed by the network management apparatus, or by the network management apparatus and the communication apparatus when the network management apparatus sets or changes an optical path that passes through plural communication apparatuses, the method comprising:
an optical signal quality deterioration amount obtaining step of obtaining an optical signal quality deterioration amount in a route of the optical path;
a modulation format selection step of selecting a modulation format in which a spectrum bandwidth is the narrowest from among modulation formats by which transmission is available on conditions of the optical signal quality deterioration amount and a desired bit rate B (bit/s);
a control message exchange step of exchanging control information for controlling a transmission unit, a receiving unit and a route exchange unit in the communication apparatus based on a selection result in the modulation format selection step, the control information being exchanged between the network management apparatus and a control unit of each communication apparatus on the optical path route;
an optical signal transmission step of generating and transmitting the optical signal of the selected modulation format and of the bit rate B (bit/s) based on the control information received by the control unit in the control message exchange step, the optical signal transmission step being performed by the transmission unit of a communication apparatus of a start point of the optical path;
a route exchange step of switching an output port of the optical path by the route exchange unit of the communication apparatuses in a section through which the optical path passes;
a bandwidth change step of changing a passband of the route exchange unit based on the control information; and
an optical path receiving step of receiving the optical path of the selected modulation format and of the bit rate B (bit/s) in the receiving unit of the communication apparatus in an end point of the optical path.

2. The bandwidth variable communication method as claimed in claim 1 , the modulation format selection step comprising:
selecting a combination of a modulation level M and a symbol rate SR that satisfies B=M×SR by using a modulation format corresponding to M multi-level modulation of optical phase, optical strength or both of the optical phase and the optical strength with a symbol rate SR (bit/s) in a single carrier.

3. The bandwidth variable communication method as claimed in claim 2 , the modulation format selection step comprising:
selecting the combination of the modulation level M and the symbol rate SR that satisfies B=M×SR×2 by further using polarized wave multiplexing.

4. The bandwidth variable communication method as claimed in claim 1 , the modulation format selection step comprising:
selecting a combination of the number N of subcarriers and a modulation level M that satisfies B=N×M×SR by using a modulation format corresponding to M multi-level modulation of optical phase, optical strength or both of the optical phase and the optical strength with an orthogonal frequency division multiplexing signal of N subcarriers and a symbol rate SR (bit/s) for each subcarrier.

5. The bandwidth variable communication method as claimed in claim 4 , the modulation format selection step comprising:
selecting the combination of the number N of subcarriers and the modulation level M that satisfies B=N×M×SR×2 by further using polarized wave multiplexing.

6. A bandwidth variable communication apparatus that is placed on a route of a link connecting between client apparatuses of a start point and an end point and that includes a function for transmitting, receiving and route-exchanging for an optical signal, the bandwidth variable communication apparatus comprising:
a transmission unit configured to generate and transmit an optical path of a desired bit rate B (bit/s);
a receiving unit configured to receive an optical path of a desired bit rate B (bit/s);
a control unit configured to receive a control signal from an external management apparatus to control the transmission unit, the receiving unit and the route exchange unit; and
a route exchange unit including a route exchange function configured to switch an output port of one or more optical paths entering from an input port based on the control signal from the control unit and a bandwidth change function configured to change a frequency bandwidth by which an optical path can pass through a section from the output port to the output port,
the control unit including:
a control transmit receive function configured to transmit and receive, with the external management apparatus, modulation format control information of the transmission unit and the receiving unit and control information of the route exchange function and the bandwidth change function of the route exchange unit, and a control function configured to control the transmission unit, the receiving unit and the route exchange unit based on the control information, wherein
the transmission unit generates and transmits an optical signal by changing the modulation format based on the control signal from the control unit,
the receiving unit performs reception corresponding to a modulation format of an optical path transmitted from another optical communication apparatus, and
the route exchange unit sets a frequency bandwidth in a section through which the optical path passes in accordance with the bandwidth of the path.

7. The bandwidth variable communication apparatus as claimed in claim 6 , wherein the transmission unit:
performs M multi-level modulation of optical phase, optical strength or both of the optical phase and the optical strength with a symbol rate SR (bit/s) using a single carrier, and
generates an optical signal by selecting a combination of a modulation level M and a symbol rate SR that satisfies B=M×SR in which transmission is available and the spectrum bandwidth is narrow according to the optical signal quality deterioration amount in the optical path route.

8. The bandwidth variable communication apparatus as claimed in claim 7 , wherein the transmission unit:
further uses polarized wave multiplexing, and
generates the optical signal by selecting the combination of the modulation level M and the symbol rate SR that satisfies B=M×SR×2 in which transmission is available and the spectrum bandwidth is narrow.

9. The bandwidth variable communication apparatus as claimed in claim 6 , wherein the transmission unit:
performs M multi-level modulation of optical phase, optical strength or both of the optical phase and the optical strength with a symbol rate SR (bit/s) for each subcarrier by using orthogonal frequency division multiplexing of N subcarriers in which frequency bands partially overlap, and
generates an optical signal by selecting a combination of the number N of subcarriers and a modulation level M that satisfies B=N×M×SR in which transmission is available and the spectrum bandwidth is narrow according to the optical signal quality deterioration amount in the path route.

10. The bandwidth variable communication apparatus as claimed in claim 9 , wherein the transmission unit:
further uses polarized wave multiplexing, and
generates the optical signal by selecting the combination of the number N of subcarriers and the modulation level M that satisfies B=N×M×SR×2 in which transmission is available and the spectru

Assignees

• Takara Hidehiko
• Jinno Masahiko
• Watanabe Atsushi
• Bartlomiej Kozicki
• Sone Yoshiaki
• Hirano Akira
• Tanaka Takafumi
• Nippon Telegraph & Telephone

Inventors

• Takara Hidehiko
• Jinno Masahiko
• Watanabe Atsushi
• Bartlomiej Kozicki
• Sone Yoshiaki
• Hirano Akira
• Tanaka Takafumi

Classifications

• H04J14/0307

  Multiplexers; Demultiplexers · CPC title

• H04J14/02122

  Colourless, directionless or contentionless [CDC] arrangements · CPC title

• H04J14/02218

  Centralized control · CPC title

• H04J14/02762

  Spectrum slot allocation · CPC title

• H04J14/0268

  Restoration of optical paths, e.g. p-cycles · CPC title