# US 9,438,368 B2 · Wavelength negotiation method and apparatus of multi-wavelength passive optical network, and multi-wavelength passive optical network system

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- Number: US 9,438,368 B2
- Document ID: US9438368B2
- Status: Granted
- Kind: B2
- Application number: 14/594,847
- Filed: 2015-01-12
- Published: 2015-05-07
- Granted: 2016-09-06
- Earliest claimed: 2012-07-13
- Assignees: Huawei Technologies Co., Ltd.
- Applicants: Huawei Technologies Co., Ltd.
- Inventors: Bo Gao; Jianhe Gao
- Web page: https://patentgrep.com/patent/US9438368B2

## CPC

- H04J 14/0246: {using one wavelength per ONU}
- H04J 14/0247: {Sharing one wavelength for at least a group of ONUs}
- H04J 14/025: {using one wavelength per ONU, e.g. for transmissions from-ONU-to-OLT or from-ONU-to-ONU}
- H04J 14/0252: {Sharing one wavelength for at least a group of ONUs, e.g. for transmissions from-ONU-to-OLT or from-ONU-to-ONU}
- H04J 14/0257: {Wavelength assignment algorithms}
- H04J 14/0267: {Optical signaling or routing}
- H04J 14/0282: {WDM tree architectures}
- H04J: MULTIPLEX COMMUNICATION (transmission in general H04B; peculiar to transmission of digital information H04L5/00; systems for the simultaneous or sequential transmission of more than one television signal H04N7/08; in exchanges H04Q11/00; stereophonic systems H04S)

## Abstract

This application provides a wavelength negotiation method of a multi-wavelength passive optical network, including: receiving a wavelength status table that is broadcast by an OLT over each downstream wavelength channel of a multi-wavelength PON system, where the wavelength status table is used to indicate information about available wavelengths of the multi-wavelength PON system and statistic information of registered ONUs of a corresponding wavelength channel; selecting an upstream transmit wavelength and a downstream receive wavelength according to the wavelength status table; and reporting information about the upstream transmit wavelength and information about the downstream receive wavelength to the OLT so that the OLT refreshes the wavelength status table. This application also provides a wavelength negotiation apparatus of the multi-wavelength passive optical network and a multi-wavelength passive optical network system.

## Claims

### Claim 1

A wavelength negotiation method of a multi-wavelength passive optical network PON, comprising:
receiving a wavelength status table that is broadcast by an optical line terminal OLT over each downstream wavelength channel of a multi-wavelength PON system, wherein the wavelength status table is used to indicate information about available wavelengths of the multi-wavelength PON system;
selecting an upstream transmit wavelength and a downstream receive wavelength;
reporting information about the upstream transmit wavelength and information about the downstream receive wavelength to the OLT;
reporting an ONU wavelength capability set to the OLT when sending a registration request or after registration succeeds; and
receiving a wavelength status subtable in a unicast manner by the OLT when it is determined that the upstream transmit wavelength or the downstream receive wavelength selected by each ONU does not meet an expected wavelength requirement, and selecting a new upstream transmit wavelength and a new downstream receive wavelength according to the wavelength status subtable, wherein
the wavelength status subtable comprises information about available wavelengths in transmit/receive wavelengths supported by the ONU.

### Claim 2 (depends on 1)

The wavelength negotiation method according to claim 1, wherein the wavelength status table comprises a list of currently available upstream wavelengths and a list of currently available downstream wavelengths, and the number of registered ONUs of a wavelength channel corresponding to each wavelength in the list of the available upstream wavelengths and the list of the available downstream wavelengths.

### Claim 3 (depends on 2)

The wavelength negotiation method according to claim 2, wherein the selecting an upstream transmit wavelength and a downstream receive wavelength according to the wavelength status table comprises:
selecting an upstream transmit wavelength and a downstream receive wavelength with a smaller number of registered ONUs or selecting an upstream/downstream transmit/receive wavelength pair with a smaller number of registered ONUs according to the number of registered ONUs of the wavelength channel corresponding to each upstream/downstream wavelength or each upstream/downstream transmit/receive wavelength pair recorded in the wavelength status table and in view of a transmit/receive wavelength capability supported by the ONUs.

### Claim 4 (depends on 1)

The wavelength negotiation method according to claim 1, wherein the wavelength status table comprises a binding relationship list of currently available upstream/downstream transmit/receive wavelengths, and the number of registered ONUs of a wavelength channel corresponding to each upstream/downstream transmit/receive wavelength pair in the binding relationship list of the currently available upstream/downstream transmit/receive wavelengths.

### Claim 5 (depends on 1)

The wavelength negotiation method according to claim 1, further comprising:
performing wavelength initialization before sending a registration request and configuring a temporary downstream receive wavelength, wherein
the wavelength status table is received from a corresponding downstream wavelength channel by means of the temporary downstream receive wavelength.

### Claim 6 (depends on 5)

The wavelength negotiation method according to claim 5, wherein the performing wavelength initialization before sending a registration request and configuring a temporary downstream receive wavelength comprise:
searching for downstream data from the OLT by gradually adjusting the downstream receive wavelength before sending the registration request; and when it is found that a downstream optical signal can be received from the OLT over a downstream receive wavelength to which the downstream receive wavelength is currently adjusted and that a correct downstream data frame can be obtained by parsing the downstream optical signal, configuring the current downstream receive wavelength as the temporary downstream receive wavelength and stopping the adjustment of the downstream receive wavelength.

### Claim 7 (depends on 1)

The wavelength negotiation method according to claim 1, further comprising:
generating a corresponding wavelength mapping relationship table entry after the OLT receives an upstream data frame or an upstream message that carries the information about the upstream transmit wavelength and the information about the downstream receive wavelength, wherein the wavelength mapping relationship table entry may comprise ONU identification information and the information about the upstream transmit wavelength and the information about the downstream receive wavelength of each ONU; and
refreshing, by the OLT, statistic information of registered ONUs of a wavelength channel corresponding to the information about the upstream transmit wavelength and information about a downstream receive wavelength in the wavelength status table according to the wavelength mapping relationship table entry.

### Claim 8 (depends on 7)

The wavelength negotiation method according to claim 7, further comprising:
refreshing, by the OLT, the wavelength status table according to a wavelength mapping table entry corresponding to a loss of signal alarm when detecting the loss of signal alarm; and
deleting, by the OLT, corresponding wavelength status information of the wavelength status table when detecting a fault of a transceiver component of the OLT.

### Claim 9

A wavelength negotiation apparatus of a multi-wavelength passive optical network (PON) comprising:
an optical receiver configured to receive a wavelength status table that is broadcast by an optical line terminal (OLT) over each downstream wavelength channel of a multi-wavelength PON system, wherein the wavelength status table is used to indicate information about available wavelengths of the multi-wavelength PON system;
a processor configured to select an upstream transmit wavelength and a downstream receive wavelength;
an optical transmitter configured to report information about the upstream transmit wavelength and information about the downstream receive wavelength to the OLT;
the optical transmitter further configured to report an ONU wavelength capability set to the OLT when sending a registration request or after registration succeeds;
the optical receiver further configured to receive a wavelength status subtable in a unicast manner by the OLT when it is determined that the selected upstream transmit wavelength or downstream receive wavelength does not meet an expected wavelength requirement;
the processor further configured to select a new upstream transmit wavelength and a new downstream receive wavelength according to the wavelength status subtable, wherein
the wavelength status subtable comprises information about available wavelengths in transmit/receive wavelengths supported by each ONU.

### Claim 10 (depends on 9)

The wavelength negotiation apparatus according to claim 9, wherein the wavelength status table comprises a list of currently available upstream wavelengths and a list of currently available downstream wavelengths, and the number of registered ONUs of a wavelength channel corresponding to each wavelength in the list of the available upstream wavelengths and the list of the available downstream wavelengths.

### Claim 11 (depends on 10)

The wavelength negotiation apparatus according to claim 10, wherein the processor comprises:
a wavelength information obtaining module, configured to: obtain, from the list of the currently available upstream wavelengths and the list of the currently available downstream wavelengths, information about the available upstream wavelengths and information about the available downstream wavelengths, and the numbers of registered ONUs of wavelength channel corresponding to each available upstream wavelength or each available downstream wavelength; and
a wavelength selecting module, configured to select an available upstream wavelength and an available downstream wavelength that correspond to a wavelength channel with a smaller number of registered ONUs as the upstream transmit wavelength and the downstream receive wavelength respectively.

### Claim 12 (depends on 9)

The wavelength negotiation apparatus according to claim 9, wherein the wavelength status table comprises a binding relationship list of currently available upstream/downstream transmit/receive wavelengths, and the number of registered ONUs of a wavelength channel corresponding to each upstream/downstream transmit/receive wavelength pair in the binding relationship list of the currently available upstream/downstream transmit/receive wavelengths.

### Claim 13 (depends on 12)

The wavelength negotiation apparatus according to claim 12, wherein the processor comprises:
a wavelength information obtaining module, configured to: obtain, from the binding relationship list of the available upstream/downstream transmit/receive wavelengths, information about available upstream/downstream transmit/receive wavelength pairs, and the number of registered ONUs of a wavelength channel corresponding to information about each available upstream/downstream transmit/receive wavelength pair; and
a wavelength selecting module, configured to select an available upstream/downstream transmit/receive wavelength pair that corresponds to a wavelength channel with a smaller number of registered ONUs as the upstream transmit wavelength and the downstream receive wavelength.

### Claim 14 (depends on 9)

The wavelength negotiation apparatus according to claim 9, wherein
the processor is further configured to perform wavelength initialization before sending a registration request, and configure a temporary downstream receive wavelength, wherein the temporary downstream receive wavelength is used as a receive wavelength for receiving the wavelength status table.

### Claim 15 (depends on 14)

The wavelength negotiation apparatus according to claim 14, wherein the processor comprises:
a wavelength adjusting module, configured to search for downstream data from the OLT by gradually adjusting the downstream receive wavelength before sending the registration request; and
a temporary wavelength configuring module, configured to: when it is found that a downstream optical signal can be received from the OLT over a downstream receive wavelength to which the downstream receive wavelength is currently adjusted and that a correct downstream data frame can be obtained by parsing the downstream optical signal, configure the current downstream receive wavelength as the temporary downstream receive wavelength and stop the adjustment of the downstream receive wavelength.

### Claim 16

A multi-wavelength passive optical network (PON) system, comprising at least one optical line terminal (OLT) and multiple optical network units (ONUs), wherein the at least one OLT is connected to the multiple ONUs in a point-to-multipoint manner by using an optical distribution network, wherein the ONUs comprise the wavelength negotiation apparatus of the multi-wavelength PON comprises:
an optical receiver, configured to receive a wavelength status table that is broadcast by an optical line terminal OLT over each downstream wavelength channel of a multi-wavelength PON system, wherein the wavelength status table is used to indicate information about available wavelengths of the multi-wavelength PON system;
a processor configured to select an upstream transmit wavelength and a downstream receive wavelength according to the wavelength status table; and
an optical transmitter configured to report information about the upstream transmit wavelength and information about the downstream receive wavelength to the OLT;
the optical transmitter further configured to report an ONU wavelength capability set to the OLT when sending a registration request or after registration succeeds;
the optical receiver further configured to receive a wavelength status subtable in a unicast manner by the OLT when it is determined that the selected upstream transmit wavelength or downstream receive wavelength does not meet an expected wavelength requirement;
the processor further configured to select a new upstream transmit wavelength and a new downstream receive wavelength according to the wavelength status subtable, wherein
the wavelength status subtable comprises information about available wavelengths in transmit/receive wavelengths supported by each ONU.

### Claim 17 (depends on 16)

The multi-wavelength passive optical network PON system according to claim 16, wherein the wavelength status table comprises a list of currently available upstream wavelengths and a list of currently available downstream wavelengths, and the number of registered ONUs of a wavelength channel corresponding to each wavelength in the list of the available upstream wavelengths and the list of the available downstream wavelengths.

### Claim 18 (depends on 17)

The multi-wavelength passive optical network PON system according to claim 17, wherein the processor comprises:
a wavelength information obtaining module, configured to: obtain, from the list of the currently available upstream wavelengths and the list of the currently available downstream wavelengths, information about the available upstream wavelengths and information about the available downstream wavelengths, and the numbers of registered ONUs of wavelength channel corresponding to each available upstream wavelength or each available downstream wavelength; and
a wavelength selecting module, configured to select an available upstream wavelength and an available downstream wavelength that correspond to a wavelength channel with a smaller number of registered ONUs as the upstream transmit wavelength and the downstream receive wavelength respectively.