Method and apparatus for controlling transmission of an upstream packet traffic in a TDM PON-based fronthaul

Patent metadata

Field	Value
Publication number	US-12185036-B2
Application number	US-201917607244-A
Country	US
Kind code	B2
Filing date	Apr 29, 2019
Priority date	Apr 29, 2019
Publication date	Dec 31, 2024
Grant date	Dec 31, 2024

Abstract

A method of controlling transmission of an upstream packet traffic from a plurality of Optical Network Units to an Optical Line Terminal in a Passive Optical Network based fronthaul network. The Optical Network Units transmit packets in a time division multiplexed access scheme to the Optical Line Terminal and the method comprises obtaining mobile upstream scheduling information, scheduling the packet traffic from the plurality of Optical Network Units based on delay constraints of the PON-based front haul network and the obtained mobile upstream scheduling information. The method also comprises transmitting the scheduling of the packet traffic to the plurality of ONUs.

First claim

The invention claimed is:

1. A method of controlling transmission of an upstream packet traffic from a plurality of Optical Network Units, ONUs, connected to an Optical Line Terminal, OLT, in a Passive Optical Network, PON, based fronthaul network, wherein the plurality of ONUs transmit packets in a time division multiplexed access scheme to the OLT, the method comprising:
obtaining mobile upstream scheduling information;
scheduling the packet traffic from the plurality of ONUs based on delay constraints of the PON-based fronthaul network and the obtained mobile upstream scheduling information, wherein scheduling the packet traffic comprises arranging an order in which the plurality of ONUs transmit their packets based on values indicative of propagation delay of optical fibers connecting the plurality of ONUs to the OLT in a descending order, wherein start of transmission of a packet by a first ONU depends on a difference between propagation delay for a preceding ONU and the first ONU and a length of a timeslot allocated to the preceding ONU; and
transmitting the scheduling of the packet traffic to the plurality of ONUs.

2. The method according to claim 1 , wherein the mobile upstream scheduling information is obtained from a Baseband Unit, BBU, associated with the OLT.

3. The method according to claim 1 , wherein scheduling the packet traffic comprises reducing a length of timeslots allocated to ONUs of the plurality of ONUs for transmission in upstream direction.

4. The method according to claim 3 , comprising:
determining a worst-case upstream total delay between the plurality of ONUs and the OLT;
if the worst-case upstream total delay is equal to or exceeds a first threshold the method comprises reducing the length of timeslots for at least one of the ONUs of the plurality of ONUS.

5. The method according to claim 1 , wherein scheduling the packet traffic comprises increasing length of timeslots allocated to ONUs of the plurality of ONUs for transmission in upstream direction.

6. The method according to claim 1 comprising:
obtaining from the plurality of ONUs information indicative of values of optical power of signals from the OLT received by the plurality of ONUs;
determining, based on the received values, power offset values for use by the ONUs when transmitting to the OLT to equalise optical power levels of the signals received at the OLT;
transmitting the offset values to the ONUs.

7. The method according to claim 1 , wherein if a baseband unit or the OLT determines from the mobile upstream scheduling information that there is at least one timeslot with no mobile upstream data to be transmitted by at least one ONU of the plurality of ONUs from a Remote Unit, RU, associated with the at least one ONU, the method comprises scheduling transmission of data in said at least one timeslot.

8. An apparatus for controlling transmission of an upstream packet traffic from a plurality of Optical Network Units, ONUs, connected to an Optical Line Terminal, OLT, in a Passive Optical Network, PON, based fronthaul network, wherein the plurality of ONUs transmit packets in a time division multiplexed access scheme to the OLT, the apparatus comprising a processing circuitry and a memory, the memory containing instructions executable by the processing circuitry such that the apparatus is operative to:
obtain mobile upstream scheduling information;
schedule the packet traffic from the plurality of ONUs based on delay constraints of the PON-based fronthaul network and the obtained mobile upstream scheduling information, wherein scheduling the packet traffic comprises arranging an order in which the plurality of ONUs transmit their packets based on values indicative of propagation delay of optical fibers connecting the plurality of ONUs to the OLT in a descending order, wherein start of transmission of a packet by a first ONU depends on a difference between propagation delay for a preceding ONU and the first ONU and a length of a timeslot allocated to the preceding ONU; and
transmit the scheduling of the packet traffic to the ONUs.

9. The apparatus according to claim 8 , wherein to schedule the packet traffic the apparatus is operative to reduce length of timeslots allocated to ONUs of the plurality of ONUs for transmission in upstream direction.

10. The apparatus according to claim 9 operative to:
determine a worst-case upstream total delay between the plurality of ONUs and the OLT;
if the worst-case upstream total delay is equal to or exceeds a first threshold the apparatus is operative to reduce the length of timeslots for at least one of the ONUs of the plurality of ONUs.

11. The apparatus according to claim 9 operative to reduce length of timeslots depending on service carried by packets transmitted by the plurality of ONUs.

12. The apparatus according to claim 8 operative to increase length of timeslots allocated to ONUs of the plurality of ONUs for transmission in upstream direction.

13. The apparatus according to claim 12 operative to:
determine a worst-case upstream total delay between the plurality of ONUs and the OLT;
if the worst-case upstream total delay is below a second threshold the apparatus is operative to increase the length of timeslots for at least one of the ONUs of the plurality of ONUs.

14. The apparatus according to claim 12 operative to increase length of timeslots depending on service carried by packets transmitted by the plurality of ONUs.

15. The apparatus according to claim 12 operative to increase length of timeslots for the ONUs of the plurality of ONUs having the upstream total delay below the second threshold.

16. The apparatus according to claim 8 operative to:
obtain from the plurality of ONUs information indicative of values of optical power of signals from the OLT received by the plurality of ONUs;
determine, based on the received values, power offset values for use by the plurality of ONUs when transmitting to the OLT to equalise optical power levels of the signals received at the OLT;
transmit the offset values to the ONUs.

17. The apparatus according to claim 8 , wherein if a baseband unit or the OLT determines from the mobile upstream scheduling information that there is at least one timeslot with no mobile upstream data to be transmitted by at least one ONU of the plurality of ONUs from a Remote Unit, RU, associated with the at least one ONU, the apparatus is operative to schedule transmission of data in said at least one timeslot.

18. The apparatus according to claim 17 operative to allocate said at least one timeslot for transmission of data by a different ONU whose delay exceeds a predefined maximum tolerated delay.

19. The apparatus according to claim 8 comprising the OLT and a baseband unit.

Assignees

• Ericsson Telefon Ab L M

Inventors

• Cavaliere Fabio
• Ruffini Stefano
• Olanders Peter

Classifications

• H04Q2011/0064

  Arbitration, scheduling or medium access control aspects · CPC title

• H04Q11/0067 Primary

  Provisions for optical access or distribution networks, e.g. Gigabit Ethernet Passive Optical Network (GE-PON), ATM-based Passive Optical Network (A-PON), PON-Ring · CPC title