Mitigating noise and OBI in RFoG networks

摘要

A system for communicating data signals over an optical transmission path combines forward signals onto a fiber that also carriers return signals. The system includes a return receiver for detecting an optical beat interference (OBI) event. Return signals are received by return receivers, one for each group of users. The fiber is provided to a splitter that distributes the forward optical receivers to the end users (RTx), which each comprise a receiver for the forward wavelength and a transmitter for the return wavelength. The transmitters provide return signals. When multiple transmitters are on at the same time, OBI events can take place when transmitter wavelengths coincide. When the return receiver detects an OBI event, it may signal the end user devices via a forward communication. The end user devices are responsive to the OBI detection signal to adjust a return wavelength to reduce or eliminate OBI.

主权项

1. A system in at least one of a headend or a node for detecting an optical beat interference (OBI) event in a two way optical communication path, the system comprising:
at least one forward transmitter for transmitting forward signals for distribution to one or more groups of end user devices, wherein each of the one or more groups includes a plurality of end user devices; at least one return receiver for receiving return signals transmitted from the one or more groups of end user devices, the return receiver including a photodetector coupled to the two way optical communication path for detecting return signals from the plurality of end user devices; a processor; and a computer readable memory including computer readable instructions which, when executed by the processor, cause the processor to:
monitor a spectrum of the return signals from each group of end users, anddetermine from the monitored spectrum of return signals if an OBI event has occurred for each respective group of end user devices,identify an end user device associated with the OBI event,generate an OBI detection signal indicative of the OBI event and identifying the end user device associated with the OBI event, andcause at least one forward transmitter to transmit the OBI detection signal in one of more of the forward signals.