Methods and systems for reducing power consumption in a multi-channel passive optical network (PON). A processor in the PON may monitor the channels in the multi-channel PON to detect a currently inactive channel, determine whether the detected channel has been inactive for an extended period of time, and deactivate the detected channel (by deenergizing transmitter(s) and/or receiver(s) associated with the detected channel) in response to determining that the channel has remained inactive for an extended period of time. The processor may re-activate the channel in response to determining that an optical signal has been reliably present on the channel for a sufficient period of time.

An optical network communication system utilizes a passive optical network (PON) and includes an optical line terminal (OLT) having a downstream transmitter and an upstream receiver, and an optical network unit (ONU) having a downstream receiver and an upstream transmitter. The downstream transmitter is configured to provide a coherent downlink transmission, and the downstream receiver is configured to obtain one or more downstream parameters from the coherent downlink transmission. The system further includes a long fiber configured to carry the coherent downlink transmission between the OLT and the ONU. The ONU is configured to communicate to the OLT a first upstream ranging request message, the OLT is configured to communicate to the ONU a first downstream acknowledgement in response to the upstream first ranging request message, and the ONU is configured to communicate to the OLT a second upstream ranging request message based on the first downstream acknowledgement.

A method includes determining a first power level by performing a first series of measurements based on a first series of burst transmissions from an optical transmitter of an optical network unit (ONU) in an optical network. Bursts in the first series of burst transmissions include a first modified preamble. A second power level is determined by performing a second series of measurements based on a second series of optical burst transmissions. Bursts in the second series of burst transmissions include a second modified preamble. A first power level (Po) and a second power level (P.sub.1) are determined based on the first power level and the second power level and one or more additional parameters associated with transmissions from the optical transmitter are determined based on P.sub.0 and P.sub.1. Based on the additional parameters, it is determined whether the optical transmitter complies with specifications of the optical network.

This application discloses a bandwidth allocation method, an optical line terminal (OLT), an optical network unit (ONU), and a system, where the method includes receiving a bandwidth request from each ONU, where the ONU includes an ONU1, generating a bandwidth map (BWMap) message according to bandwidth requested by the ONU and bandwidth configured for the ONU, where the BWMap message includes a first allocation identifier (Alloc-ID1), a first time corresponding to the Alloc-ID1, a second allocation identifier (Alloc-ID2), and a second time corresponding to the Alloc-ID2, and both the Alloc-ID1 and the Alloc-ID2 are allocated to the ONU1 for use, and sending the BWMap message to each ONU. Therefore, a problem that a transmission delay does not satisfy a requirement when a passive optical network (PON) system is applied to mobile backhaul is resolved, a data transmission rate and data transmission efficiency are improved, and user satisfaction is improved.

A wavelength and bandwidth allocation method which includes in order a wavelength determination step S4 of determining a plurality of wavelengths of an uplink signal from each ONU to OLT to guarantee a guaranteed bandwidth corresponding to a subscription service class of each ONU and a reference bandwidth distribution step S5 of distributing, as reference bandwidths, all bandwidths of the plurality of wavelengths determined in the wavelength determination step S4 to each ONU according to the subscription service class of each ONU and making the reference bandwidths of ONUs whose subscription service classes are the same be the same.

The invention provides a method and apparatus for reconfiguring wavelength of the ONU. To be specific, the OLT sends a Deactivate_ONU-ID message to the ONU, the Deactivate_ONU-ID message including a reconfiguration flag, a new receive wavelength assigned for the ONU and a new transmit wavelength assigned for the ONU. After receiving the Deactivate_ONU-ID message from the OLT, the ONU discards the TC layer parameters related to the current wavelength channel, and determines whether the reconfiguration flag included in the Deactivate_ONU-ID message indicates the receive wavelength and the transmit wavelength of the ONU are required to be reconfigured. If so, then the ONU replaces its original receive wavelength and original transmit wavelength with its new receive wavelength and the new transmit wavelength included in the Deactivate_ONU-ID message, and enters initial state; and if not, then the ONU enters initial state directly.

Provided are a distance measurement method, device and system. In the method, an Optical Line Terminal (OLT) commands an Optical Network Unit (ONU) to perform wavelength tuning; and when a message indicating that the wavelength tuning is completed is received from the ONU, the OLT measures a distance to the ONU.

Systems and methods for optical modulation index calibration in a CATV network.

Example embodiments describe an optical line terminal, OLT, configured to perform determining a fragmentation allocation for respective ONUs; and notifying, the respective ONUs, of the fragmentation allocation. Other example embodiments relate to an optical network unit, ONU, configured to perform receiving, from the OLT, fragmentation allocation for fragmenting one or more packets; processing the packets in accordance with the fragmentation allocation to obtain fragmented and unfragmented packets; and forwarding, to the OLT, the fragmented and unfragmented packets in accordance with the dynamic upstream allocation map.

A method includes determining a first power level by performing a first series of measurements based on a first series of burst transmissions from an optical transmitter of an optical network unit (ONU) in an optical network. Bursts in the first series of burst transmissions include a first modified preamble. A second power level is determined by performing a second series of measurements based on a second series of optical burst transmissions. Bursts in the second series of burst transmissions include a second modified preamble. A first power level (P.sub.0) and a second power level (P.sub.1) are determined based on the first power level and the second power level and one or more additional parameters associated with transmissions from the optical transmitter are determined based on P.sub.0 and P.sub.1. Based on the additional parameters, it is determined whether the optical transmitter complies with specifications of the optical network.