1. doc.: IEEE 802.11-13/1377r0 Submission November 2013 Jeongki Kim, LG ElectronicsSlide 1 DL efficiency enhancement in high dense network Date: 2013-11-10 Authors: NameAffiliationsAddressPhoneEmail Jeongki KimLG Electronics 19, Yangjea-daero 11gil, Seocho-gu, Seoul 137-130, Korea jeongki.kim@lge.com Kiseon RyuLG Electronicskiseon.ryu@lge.com Suhwook KimLG Electronicssuhwook.kim@lge.com Giwon ParkLG Electronicsgiwon.park@lge.com HanGyu ChoLG Electronicshg.cho@lge.com

2. doc.: IEEE 802.11-13/1377r0 Submission Abstract This contribution introduces an approach for enhancing DL efficiency in dense WLAN environment. Slide 2Jeongki Kim, LG Electronics November 2013

3. doc.: IEEE 802.11-13/1377r0 Submission 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 Jeongki Kim, LG ElectronicsSlide 3 November 2013

4. doc.: IEEE 802.11-13/1377r0 Submission 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 Jeongki Kim, LG ElectronicsSlide 4 November 2013

5. doc.: IEEE 802.11-13/1377r0 Submission 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 Jeongki Kim, LG ElectronicsSlide 5 November 2013

6. doc.: IEEE 802.11-13/1377r0 Submission 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? Jeongki Kim, LG ElectronicsSlide 6 November 2013

7. doc.: IEEE 802.11-13/1377r0 Submission 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 Jeongki Kim, LG ElectronicsSlide 7 November 2013

8. doc.: IEEE 802.11-13/1377r0 Submission References [1] IEEE 802.11-13/0657r6 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 11th IEEE International Conference on Network Protocols, 2003. [3]Byeong Gi Lee and Sunghyun Choi, Broadband wireless access and local networks: Mobile WiMAX and WiFi, Artec House, 2008 Jeongki Kim, LG ElectronicsSlide 8 November 2013