On QoS Aware Uplink Improvement in Multi-Wavelength PON System

1. On QoS Aware Uplink Improvement in Multi-Wavelength PON System FRONT. SJTU Boven Yan May 4th

2. Physical Basis • WDM PON with uplink multicast • Still no related works (ICC 2009) • Colorless downstream multicast, uplink unicast • OFDM PON • Easy to reach uplink multicast • Sub-frequency re-modulation • Problems • In WDM system, if colorless is to be key design, then uplink will be linked with downlink, uneven bidirectional traffic will not be satisfied.

3. Per-stream scheduling requirements • Each ONU should be guaranteed minimum bandwidth as its own admission control capacity. • Dedicate resource • Shared resource • Service should be treated with EF, AF, BE standard • When dedicate resource are underutilized, they should be used to improve overall performance though it shouldn’t view as idle resource to accept new service.

4. Design Key Points • For EF service, use deterministic estimation for grant sizing.For AF, use credit mechanism for grant sizing. For BE, allocate rest bandwidth. • From offline to ‘on the fly’ • Guarantee fairness first • Then consider full utilization of bandwidth.

5. Drawback of Deterministic Method • Fail to provide fairness for each ONU • First-in service is much easier for latter service to be assigned admission. • With deterministic method the control is not accurate esp. for AF service. Bandwidth filling won’t fully utilize them.

6. Design 1 Dedicate-shared wavelength

7. Drawback of Design - 1 • Uneven traffic for different ONUs • ONU1 is lightly loaded while ONU2 ONU3 ONU4 is heavily loaded. • To improve performance for these ONUs, we could assign partially some idle bandwidth in ONU1 for ONU2, ONU3, ONU4’s AF or EF traffic, however, that will cause S1- S8 no longer dedicate and when to choose an unified DBA time to be difficult.

8. Design - 2 • Centralized allocation: • Simultaneous scheduling • Capacity is determined by virtual dedicate sub-frequency band • The allocated band are finally integrated into a block consisting of several sub-frequency.

9. Design - 2

10. Design - 2

11. Design-2 DWBA • For BE Available Bandwidth • BBE avail = N × Bmin • Total EF and AF Available Bandwidth • B EF+AF avail= K × Bcycle – B BE avail • DWBA process • BBE(n) = min { BBE avail, Breq BE (n)} • BEF(n) = T × CEF(n) + B req EF (n) + TDWBA+RTT1 • BAF(n) = T × C AVG AF (n) + min{ B req AF(n) , Credit Limit(n) } +TDWBA+RTT1 • T= (∑ BEF(n) + ∑ BAF(n) + ∑ BBE(n) ) / K

12. Design-2 Admission Control • BE service will always be accept • EF and AF service: • Use deterministic method to determine C avg EF/AF of the service and check whether the total band has idle space • Maintain a resource allocate charter with virtual dedicate bandwidth and virtual shared bandwidth like previously stated. Fig1

13. Further discussion • How to deal with bursty service. • How to conduct on the fly scheduling instead of total offline scheduling like in this process. • For WDM – OFDM – TDM system. How to further utilize multi – wavelength resource?

14. Thanks!