doc: IEEE /625r1 Submission Amjad Soomro et. al September 2002 Slide 1 TGe ‘Fast track’ proposed Draft Normative Text Changes Sai Shankar, Javier del Prado, Amjad Soomro, Kiran Challapali, Atul Garg, Benno Ritter, Philips Mathew Sherman, AT&T Partho Mishra, Frank Howley, Rolf De Vegt, Airgo Mathew Shoemake,TI Morihiko Hayashi, Sony Isaac Lim Wei Lih, Matsushita

doc: IEEE /625r1 Submission Amjad Soomro et. al September 2002 Slide 2 Outline Overview of the rate-based proposal Description of proposed changes Comparison with Time-based proposal Conclusion

doc: IEEE /625r1 Submission Amjad Soomro et. al September 2002 Slide 3 Rate-Based Proposal Application Interface Air Interface MAC PHY Application Rate-based Negotiation: Rate-based Announce Service Schedule 1 23 Application (in WSTA) requests “Rate,” across the application interface TSPEC in the form of min/mean/max rate, delay.. WSTA requests HC for Rate HC negotiates and admits stream, announces schedule for the WSTA Schedule re-announced, if needed –No renegotiations 1 2 3

doc: IEEE /625r1 Submission Amjad Soomro et. al September 2002 Slide 4 Changes to the Text Suggested text for TSPEC Suggested text for Announced Schedule Definition of normative behavior of scheduler added

doc: IEEE /625r1 Submission Amjad Soomro et. al September 2002 Slide 5 TSPEC element Application (in WSTA) requests “Rate,” across the application interface WSTA requests service from HC for a TS using the above format

doc: IEEE /625r1 Submission Amjad Soomro et. al September 2002 Slide 6 TSPEC element (Contd.) Suggested text for TSPEC that clarifies the definition of parameters All parameters do not need to be specified by an application –A zero value indicates parameter is unspecified Added “Peak data rate” field to TSPEC –for clarification of maximum burst size TSPEC is encoded using TLV

doc: IEEE /625r1 Submission Amjad Soomro et. al September 2002 Slide 7 Schedule Element HC negotiates and admits stream, announces schedule The scheduling information is sent using a Schedule QoS Action frame Announcing the schedule addresses power management solidly –without putting undue restriction on the scheduler –without requiring changes to the API

doc: IEEE /625r1 Submission Amjad Soomro et. al September 2002 Slide 8 Scheduler Behavior Added section on “Schedule management by the HC” Defined normative behavior for the scheduler –in terms of bounds Defined the following –Maximum Inter TXOP Interval –Minimum Inter TXOP Interval –Minimum TXOP Duration –TXOP duration between successive TXOP allocations

doc: IEEE /625r1 Submission Amjad Soomro et. al September 2002 Slide 9 Queue Flow Time-based MAC PHY Application Interface Air Interface Negotiation:Time-based MAC PHY Application Rate-based Negotiation: Rate-based Announce Service Schedule Time-based Proposal Rate-based Proposal Protocol Comparison

doc: IEEE /625r1 Submission Amjad Soomro et. al September 2002 Slide 10 Comparison (Contd.) Time-based Proposal Application (in WSTA) requests “Air time,” across the application interface Air time in form of TXOP duration and its frequency WSTA requests HC for time HC negotiates and grants TXOPs If channel conditions change (or new stream admitted), HC has to renegotiate with WSTA Rate-based Proposal Application (in WSTA) requests “Rate,” across the application interface Rate in the form of min rate, max rate and delay WSTA requests HC for Rate HC negotiates and admits stream, announces schedule HC has enough information if channel conditions change, no renegotiations

doc: IEEE /625r1 Submission Amjad Soomro et. al September 2002 Slide 11 Application Needs Throughput in a Wireless channel can vary significantly –Due to multi-path, interference, etc. Application needs continuity –Yet, provisioning for the worst case is very inefficient –Application may prefer to have rate reduced (say by 20%) rather than be bumped out Therefore, support for VBR is essential from an application point of view –CBR: special case of VBR Rate-based approach allows VBR applications –An efficient (high-load) solution for time varying channel

doc: IEEE /625r1 Submission Amjad Soomro et. al September 2002 Slide 12 Benefits of Rate-based approach Applications using Rate parameters “natural” across Application Interface An efficient (high-load) solution for time varying channel –Rate-based approach supports VBR (VBR superset of CBR) –Rate-based approach the solution for high-load cases –Complements E-DCF that works well for low-load cases –Retains HC flexibility Complexity –Rate-based does not have the complexity due to renegotiations Wireless link changes constantly, VBR... –Conversion from rate-based to a schedule can be simple –WSTA can be thin-clients (several WSTAs per AP) Rate-based approach supports power management –Schedule is available to WSTA to go to sleep

doc: IEEE /625r1 Submission Amjad Soomro et. al September 2002 Slide 13 Conclusions TSPEC negotiation per TS –Per stream QoS requirements can be met –However, aggregation possible Schedule Announcement –Power Management –Early local schedule determination at WSTA No undue restrictions on scheduling VBR is naturally addressed