November 2013 doc IEEE 802 11 -13 1377

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November 2013 doc. : IEEE 802. 11 -13/1377 r 0 DL efficiency enhancement in high dense network Date: 2013 -11 -10 Authors: Name Jeongki Kim Kiseon Ryu Suhwook Kim Giwon Park Han. Gyu Cho Submission Affiliations LG Electronics LG Electronics Address 19, Yangjea-daero 11 gil, Seocho-gu, Seoul 137 -130, Korea Slide 1 Phone Email jeongki. kim@lge. com kiseon. ryu@lge. com suhwook. kim@lge. com giwon. park@lge. com hg. cho@lge. com Jeongki Kim, LG Electronics

November 2013 doc. : IEEE 802. 11 -13/1377 r 0 Abstract • This contribution introduces an approach for enhancing DL efficiency in dense WLAN environment. Submission Slide 2 Jeongki Kim, LG Electronics

November 2013 doc. : IEEE 802. 11 -13/1377 r 0 Motivation • DL efficiency is significantly getting worse in high dense networks due to the following reasons – There are more buffered data in AP in high dense STA network – Also, AP’s DL TX opportunities becomes smaller due to the contention with many STAs [2][3] • TX opportunity of AP = 1/(N+1) (N: No. of non-AP STAs within a BSS) – Increased collision makes the doubled contention window [2][3] • TX delay becomes longer due to large CW – Smaller TX opportunity and longer TX delay, more buffered data • The buffer can be overflown in case of severe high dense environment • Some buffered data may be discarded – Repeated vicious circle degrades the DL throughput rapidly • HEW needs to enhance DL efficiency in dense network by prioritizing DL traffic Submission Slide 3 Jeongki Kim, LG Electronics

November 2013 doc. : IEEE 802. 11 -13/1377 r 0 Possible approaches • Possible methods for enhancing the DL throughput in dense networks – Option 1: Giving higher TX priority to AP (e. g. , small IFS, small CW) • May increase the collision • Unfairness with STAs and increasing the number of pending STAs – Option 2: Time-dedicated DL access (e. g. , In the Beacon) • DL dedicated interval can increase the UL access delay of STAs • To avoid the problems in the above, this contribution suggests a frequency-dedicated DL access Submission Slide 4 Jeongki Kim, LG Electronics

November 2013 doc. : IEEE 802. 11 -13/1377 r 0 DL oriented channel design • DL oriented channel: The channel on which DL frames are sent to associated STAs and on which UL data is not sent • Link setup procedures (e. g. , authentication, association) can be performed on the normal channel Submission Slide 5 Jeongki Kim, LG Electronics

November 2013 doc. : IEEE 802. 11 -13/1377 r 0 Further discussion points • Which frames can be sent on the DL oriented channel? – Stand-alone DL frame (e. g. , DL data, DL control/management frame like RTS) – DL-dependant UL frame (e. g. , ACK for DL frame , CTS for DL RTS) – Others? • DL frame TX method on DL oriented channel – Legacy methods(e. g. , DCF, PCF, EDCA, HCF, etc. ) – Or need new methods? • Issues in overlapping BSSs – Coexistence with legacy primary/secondary channel of neighbor BSS – DL oriented channels of OBSSs are same channels or Different? • Others? Submission Slide 6 Jeongki Kim, LG Electronics

November 2013 doc. : IEEE 802. 11 -13/1377 r 0 Conclusion • DL throughput is degraded drastically in dense WLAN environment – Because AP sends the DL data with the same priority as many non. AP STAs with its BSS • One method to increase the DL efficiency is to reduce the level of contention with non-AP STAs • We propose the concept of DL oriented channel as a candidate technology of HEW to minimize the contention with non-AP STAs when AP sends DL data to STAs Submission Slide 7 Jeongki Kim, LG Electronics

November 2013 doc. : IEEE 802. 11 -13/1377 r 0 References • • • [1] IEEE 802. 11 -13/0657 r 6 Usage models and requirements for IEEE 802. 11 High Efficiency WLAN study group (HEW SG) [2] Marcelo M. Carvalho and J. J. Garcia-Luna-Aceves, Delay Analysis of IEEE 802. 11 in Single-Hop Networks, In Proceedings of the 11 th IEEE International Conference on Network Protocols, 2003. [3]Byeong Gi Lee and Sunghyun Choi, Broadband wireless access and local networks: Mobile Wi. MAX and Wi. Fi, Artec House, 2008 Submission Slide 8 Jeongki Kim, LG Electronics

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