doc.: IEEE /0805-r1 SubmissionSlide 1 On Definition of Dense Networks and Performance Metric Date: Authors: Jianhan Liu, etc. Mediatek Inc. July 2013

doc.: IEEE /0805-r1 Submission Usage models and HEW focus Slide 2 Jianhan Liu, etc. Mediatek Inc. The usage categories for WFA liaison was presented in HEW teleconferences [1] 1 high density of APs and high number of STAs per AP astadium bairport/train stations cexhibition hall dshopping malls eE-Education f Large-scale deployment with high density in City Square/Hot Spot 2high density of STAs adense wireless office bpublic transportation clecture hall 3 high density of APs (low/medium number of STAs per AP) adense apartment building bCommunity WiFi 4new outdoor deployments aVery dense urban Street – Public Access bPico-cell street deployment – Public Access cCellular offload - co-site offloading 5single-link throughput increase asurgery/health care (2e from 11ac) bproduction in stadium (similar to 1d-1e from 11ac) csmart car July 2013

doc.: IEEE /0805-r1 Submission Definition of Dense Network and Performance Metric Slide 3 Jianhan Liu, etc. Mediatek Inc. HEW’ s Goal: Improve efficiency in high density WLAN –How to define a density network? –How much performance enhancement we should expect in different usage cases? Proposed Performance Metric –BRCM Proposed performance metric as bps/ square meter [2] –Huawei proposed the performance metric also considers power /energy consumption in [3] –Basically, Area throughput is the main performance metric –Is bps/square meter or area throughput the best metric in high density WLAN? July 2013

doc.: IEEE /0805-r1 SubmissionSlide 4 Jianhan Liu, etc. Mediatek Inc. Area Throughput and Average Throughput per STA Area throughput is equivalent to average throughput per STA when the density of the network is given. –For a given area with x square meters, area throughput is –Given the density of the network, average throughput per STAs is –If the network density is set, average throughput per STAs is just a constant scaling of area throughput. –Notes: Average throughput per STA is more closely to user experience. Density should be included into performance metric. July 2013

doc.: IEEE /0805-r1 SubmissionSlide 5 Jianhan Liu, etc. Mediatek Inc. Average Throughput per STA Decaying Bound Average Throughput per STA decays at least inversely with density –Without considering sum throughput decrease due to collisions –Assume that the sum throughput in a given area is constant R (say, the throughput of a sparse network), then the throughput per STA can be written as Two Key Observations: 1.For dense networks that there are a lot of STAs per AP, the average throughput per STA is impossible to guarantee. 2.Area throughput is not changed in this case. However, user experience becomes horrible when density is high July 2013

doc.: IEEE /0805-r1 Submission What a density network problem possibly has a nice solution? Slide 6 Jianhan Liu, etc. Mediatek Inc. 1high density of APs and high number of STAs per AP astadium bairport/train stations cexhibition hall dshopping malls eE-Education fLarge-scale deployment with high density in City Square/Hot Spot 2high density of STAs adense wireless office bpublic transportation clecture hall 3high density of APs (low/medium number of STAs per AP) adense apartment building bCommunity WiFi For category 1 and 2 with high number of STAs per AP: –the enhancement room is to approach the bound by reducing collisions. User experience is still not good even it is optimized. Category 3 is a more interesting problem in HEW’s –Can user experience per STA be the same as in it in sparse network? Theoretically, it is possible. July 2013

doc.: IEEE /0805-r1 Submission Summary and Discussions Using area throughput as the performance metric needs more discussion –Area throughput in some cases does not reflects the user experience –For example, Average throughput per STA reflects the user experience more directly –Average throughput per STA includes the density factor –Minimum or outage data rate also reflects user experience than area throughput [4] –Other QoE metrics also be included in the performance metric. July 2013 Slide 7 Jianhan Liu, etc. Mediatek Inc.

doc.: IEEE /0805-r1 Submission Reference [1] “Usage models for IEEE High Efficiency WLAN study group (HEW SG) –Liaison with WFA”, IEEE /0657r2, Laurent Cariou, etc. [2] “HEW- Metrics, Targets, Simulation Scenarios”, IEEE /0486r1, Ron Porat, etc. [3] “HEW Functional Requirements”, IEEE /0524r2, Tianyu Wu, etc. [4] “Quantitative QoE Requirements for HEW”, IEEE /0850, Huairong Shao, etc. Slide 8 Jianhan Liu, etc. Mediatek Inc. July 2013