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Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)

Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [MAC Access Priorities] Date Submitted: [8 July 2008] Source: [Benjamin A. Rolfe] Company [Blind Creek Associates] Address [] Voice:[+1.408.395.7207] E-Mail:[ben@blindcreek.com] Re: []

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Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)

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  1. Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [MAC Access Priorities] Date Submitted: [8 July 2008] Source: [Benjamin A. Rolfe] Company [Blind Creek Associates] Address [] Voice:[+1.408.395.7207] E-Mail:[ben@blindcreek.com] Re: [] Abstract: Discussion of a proposal to add prioritized channel access to the MAC. Purpose: To stimulate discussion I task group 15.4e Notice: This document has been prepared to assist the IEEE P802.15. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by P802.15. Ben Rolfe

  2. Channel Access Priorities Overview Benjamin A. Rolfe ben@blindcreek.com Ben Rolfe

  3. Summary/Contents • Purpose and Goals • Kinds of Priority Ben Rolfe

  4. Purpose and Goals Purpose • Stimulate Task Group discussion Goals of prioritized access: • Improved QoS • Improve channel usage effectiveness • Save power • Improved coexistence • More robust system Ben Rolfe

  5. Types of Priority • User Priority (Traffic Class, etc) • Assigned by Higher Layer Entities • Based on kind of payload • Channel Access Priority • Determined by the MAC • Based on NHL parameters and known conditions Ben Rolfe

  6. MAC-SAP • MAC data request • User Priority (Traffic Class) • Other control parameters? Ben Rolfe

  7. Channel Access Priority (Cpri) • Cpri can take into account (for example) • User Priority and Parameters • Remaining time to live (TTL) • Likelihood of Success • Fairness • Cpri used to • Figure which frame goes next • Modify CSMA (Contention Access) Ben Rolfe

  8. Channel Access • Contention Based • Cpri modified CSMA • Back-off extension to ‘listen’ period (d/Cpri) • Higher priority “wins” • Can lead to fewer collisions • Contention Free • What goes next • Clean out old/hopeless frames Ben Rolfe

  9. Backwards Compatibility • Channel Access • CSMA not broken: • Legacy nodes look like high Cpri • No impact on receiver • MPIB parameters: • Number of U-pri / Pri-enabled • MAC-SAP: optional parameters Ben Rolfe

  10. Fitting the 802.15.4 Architecture • Keeping it Simple • Info from higher layers • More MAC memory (Queues) • Timing mechanism (coarse) • Minimal extension to CSMA algorithm Ben Rolfe

  11. The End Thanks ben@blindcreek.com Ben Rolfe

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