System and method for increasing upstream capacity in an optical network

An optical line terminal (OLT), comprising:

• a plurality of receivers configured to receive traffic in an upstream transmission channel from a plurality of ONUs, wherein each of the ONUs may transmit at any wavelength within a wavelength band associated with the upstream transmission channel, and wherein the wavelengths at which the plurality of ONUs transmit are normally distributed around a single nominal, upstream transmission wavelength of the upstream transmission channel, the normal distribution of the wavelengths having a standard deviation;
• and
• a signal processing module configured to:
• divide the upstream transmission channel into a plurality of sub-channels, wherein each of the plurality of sub-channels comprises a subset of the wavelength band associated with the upstream transmission channel, and wherein each of the plurality of sub-channels has a wavelength band that is less than the standard deviation of the normal distribution of the wavelengths;
• dynamically determine the identity of each of the plurality of ONUs transmitting in each of the sub-channels;
• dynamically assign each of the plurality of ONUs transmitting in the upstream transmission channel to at least one of the sub-channels based on the determination that the ONU is transmitting in that sub-channel, wherein at least two ONUs are assigned to the same sub-channel;
• allocate transmission timeslots for time-shared transmission by the ONUs assigned to the same sub-channel;
• and
• after dynamically assigning the ONUs to sub-channels, determining that one or more of the ONUs is transmitting in a different sub-channel than the assigned sub-channel.

A passive optical network (PON) comprising:

• means for receiving traffic from a plurality of optical network units (ONUs) transmitting in an upstream transmission channel, wherein the plurality of ONUs each transmit at a different wavelength within a band of wavelengths associated with the upstream transmission channel, and wherein the wavelengths at which the plurality of ONUs transmit are normally distributed around a single nominal, upstream transmission wavelength of the upstream transmission channel, the normal distribution of the wavelengths having a standard deviation;
• means for dividing the upstream transmission channel into a plurality of sub-channels, wherein each of the plurality of sub-channels comprises a subset of the band of wavelengths associated with the upstream transmission channel, and wherein each of the plurality of sub-channels has a wavelength band that is less than the standard deviation of the normal distribution of the wavelengths;
• means for determining the identity of each of the plurality of ONUs transmitting in the upstream transmission channel;
• means for assigning each of the plurality of ONUs transmitting in the upstream transmission channel to at least one of the plurality of sub-channels based on the determination that the ONU is transmitting in that sub-channel, wherein at least two ONUs are assigned to the same sub-channel;
• means for allocating transmission timeslots for time-shared transmission by the ONUs assigned to the same sub-channel;
• and
• means for determining, after dynamically assigned the ONUs to sub-channels, that one or more of the ONUs is transmitting in a different sub-channel than the assigned sub-channel.