Texas Instruments Incorporated Month 2000 doc.: IEEE 802.11-00/xxx January 2001 Enhanced Contention Period Proposal for QoS and Throughput Enhancements - Summary Sid Schrum, Donald P. Shaver, Jin-Meng Ho, Khaled Turki and Matthew B. Shoemake Texas Instruments Incorporated 12500 TI Blvd. Dallas, Texas 75243 (214) 480-4349 (Shaver), (214) 480-1994 (Ho), (919) 463-1043 (Schrum), (214) 480-6908 (Turki) (214) 480-2344 (Shoemake) shaver@ti.com, jinmengho@ti.com, sschrum@ti.com, khaled@ti.com, shoemake@ti.com Sid Schrum et. al ,Texas Instruments John Doe, His Company

Key Features Contention–Free Access during Contention Period January 2001 Key Features Contention–Free Access during Contention Period EAP / HC CF Access in CP Poll / Ack CF exchange sequences (CFP-like) ESTA to ESTA Contention Free Burst Poll Request: STA request for CF access Contention Access Probabilistic Access Mechanism Adaptive Contention Sid Schrum et. al ,Texas Instruments

Contention-Free Access January 2001 Contention-Free Access New use of existing timing hierarchy (SIFS, DIFS, etc.) allows for contention free access during contention period Different primary access mechanism vs. CFP, similar function Positive benefits of contention free access and CFP-like exchange sequences without access delay of CFP Allows EAP to transmit QoS traffic to STAs without contention Allows EAP to initiate Poll-Ack-w/data sequences, and for ESTAs to respond without contention Allows for piggybacked Acks Mitigates inter-BSS interference Improves channel reuse Offers opportunity to consolidate Level 1 and Level 2 QoS Sid Schrum et. al ,Texas Instruments

CF Access Extensions ESTA to ESTA contention free exchange January 2001 CF Access Extensions ESTA to ESTA contention free exchange Benefits of contention free access Better utilization of available channel vs. STA to AP to STA transfer Poll Request allows ESTA to request contention free access via EAP initiated Poll / Ack sequence Reduces contention when a burst of frames is available for transmission Sid Schrum et. al ,Texas Instruments

Probabilistic Access Method January 2001 Probabilistic Access Method Utilizes Permission Probabilities to determine when to transmit Similar to current backoff scheme in that current timing hierarchy applies (use of slot times), and collisions result in backoff Compatible with CC/RR which also contends by probability Different method of picking which slot to use for transmission. Results in improved channel access characteristics and enables immediate application of updated access parameters to contending traffic Sid Schrum et. al ,Texas Instruments

January 2001 Adaptive Contention EAP / HC updates permission probabilities based upon detected channel load Utilizes lessons learned from Ethernet Simulation results show Probabilistic Access + Adaptive Contention results in improved channel access characteristics and throughput Delivery delay mean and variance key metrics Sid Schrum et. al ,Texas Instruments