Evaluation Criteria and Simulation Scenarios

1. Evaluation Criteria and Simulation Scenarios Authors: Date: July 16, 2013 Klaus Doppler, Nokia

2. July 2013 Abstract • The presentation proposes evaluation criteria for HEW • The presentation introduces the requirements of the simulation scenarios • One new simulation scenario for high density of APs and high density of terminals per AP is proposed Klaus Doppler, Nokia

3. Recap, mission of HEW • Creation of HEW • Do you support starting a new study group called “high efficiency WLAN” to enhance 802.11 PHY and MAC in 2.4 and 5GHz with a focus on: • Improving spectrum efficiency and area throughput • Improving real world performance in indoor and outdoor deployments • in the presence of interfering sources, dense heterogeneous networks • in moderate to heavy user loaded APs • Evaluation criteria and simulation scenarios • Reflect the focus of HEW • Provide significant step forward from 802.11ac that is noticeable by the end user Klaus Doppler, Nokia

4. Proposed evaluation criteria • The proposal is to have two criteria for proposal evaluation • Area throughput • 5 percentile user throughput • Area throughput [bit/s/Hz/m2] • HEW focus is system efficiency that is measured by area throughput • Aggregate throughput for a given number of APs and STAs in a given area and given frequency band. The simulation scenario defines the available spectrum and APs optimize the use of the spectrum • Similar to average BSS throughput or average STA throughput in homogenous scenario Klaus Doppler, Nokia

5. Proposed evaluation criteria • 5 percentile of user throughput cumulative distribution function (CDF) • CDF of user throughput indicates nicely the distribution of the throughputs • Users expect a consistent user experience from wireless networks, i.e. when connected they expect at least minimum performance • 5 percentile of the user throughput CDF is a good measure of the minimum performance; at least 95% of users gets better throughput • The area throughput and 5 percentile user throughput are evaluated at the same time • The area throughput and 5 percentile user throughput are calculated per access category Klaus Doppler, Nokia

6. Requirements for simulation scenarios • The simulation scenarios are examples to proof that HEW performance criteria are fulfilled • They enable benchmarking of the proposed enhancements • Should reflect the intended use of HEW • Should be clearly defined and simple enough that they can be implemented by a large set of companies • Large set of companies need to contribute to HEW to make it successful • It is important that new concepts and features are evaluated in the intended usage scenarios Klaus Doppler, Nokia

7. Requirements for simulation scenarios • There should be relevant number of simulation scenarios to demonstrate HEW performance in different scenarios • Baseline scenarios need to be agreed to be able to compare results of different companies • Calibration and understanding of simulation results is important • 802.11n or 802.11ac scenarios may be used to verify the correctness of the simulator Klaus Doppler, Nokia

8. Simulations scenarios of 802.11n • 802.11n defines 5 simulation scenarios (11-03/814r31) • The simulation scenarios focus on the performance of single BSS • The simulation scenarios contain different traffic types; VoIP, low throughput streaming and best effort data • The transmitted traffic types, and locations of the AP and terminals are precisely defined • A lot of simulation results were published. Many simulations results show: • QoS is achieved. The high Access category traffic is transmitted and remaining capacity is left to best effort data • By tuning the EDCA parameters, the results can be set to favor high priority or best effort data Klaus Doppler, Nokia

9. Simulation scenarios of 802.11ac • 802.11ac defines 5 simulation scenarios (11-09/451r16) • The simulation scenarios focus on the performance of single BSS and simple overlapping BSSs • The simulation scenarios contain high bit rate real time video streaming and best effort data • The transmitted traffic types, and locations of the APs and terminals and are precisely defined • The primary channels and bandwidths of the APs are precisely defined • No simulation results were published • Hard to estimate 802.11ac performance Klaus Doppler, Nokia

10. Shortcomings of 802.11ac scenarios for HEW • Scenario 4 (OBSS scenario) of 802.11ac • Number of OBSSs and STAs is low • Checking user throughput for each STA may be cumbersome and hard to compare • Defining a large scenario with this level of details is complicated Klaus Doppler, Nokia

11. New scenario, network topology and device locations • Multi-floor building • Important scenario in many countries. Fiber to the home offers >>1Gbps backhaul capacity • 10 floors, 3 m height in each floor • 2x10 rooms in each floor • Room size:10m x 10m x 3m • AP locations (assuming 150 APs): • Place 150 APs in the randomly selected rooms at xy-location (uniform distribution) at 1.5m above floor level • At maximum one AP per room • STA locations, 5 STA/AP (=750 STAs): • In each room that has an AP, place five STAs in random xy-locations (uniform distribution) at 1.5m above the floor level • Each of the five STAs in a room is associate to the AP in the room July 2013 Klaus Doppler, Nokia

12. New scenario, traffic model and channel assignment • Constant Bit Rate traffic of DL or UL traffic • DL or UL traffic is randomly assigned to a STA • 80% of STA with 100Mbps DL traffic • 20% of STA with 100Mbps UL traffic • Packet size 1500B • 5GHz: at least 3 non-overlapping 80MHz channels • Option 1: Random assignment of AP to channel • Option 2: Simple distributed assignment • Step 1: Each AP picks random channel • Step 2: Randomly selected AP picks channel with maximum pathloss to next AP • Step 3: Repeat Step 2 10xNumAP to find the best operating channel for each AP • Run simulations with resulting channel assignment • 2.4GHz: 3 non-overlapping 20MHz channels • Same assignment procedure as in 5GHz • 802.11n channelization may be used at 2.4 GHz Klaus Doppler, Nokia

13. New scenario, simulation run parameters • The scenario should be simulated at least 10 times • In each simulation the locations and APs and STAs are randomly selected • Each simulation run should simulate at least 10s of time • The simulation run may contain only APs operating at the same 80 MHz channel and associated STAs • Option 1 All APs have the same primary channel • APs and STAs operating outside the 80MHz channel need not be simulated • 50 APs and 250 STAs are present in one simulation run • Option 2: Free selection of the primary channel Klaus Doppler, Nokia

14. Baseline scenario example parameters • The values may be optimized. The values of the these paramters should be listed with the simulation results. • Transmit power • Max AP TxP 23dBm • Max STA TxP 19dBm • Antenna configuration • MIMO / beam forming • AP/STA: 2/2 • AP/STA: 4/2 • Antenna gain • Option 1: 0dBi Omni antenna pattern • Option 2: 3dBi 3D dipole antenna pattern • Power control • Link Adaptation • Enabled: SNR based? • Carrier Sensing • PD threshold -82dBm • ED threshold -62dBm • EDCA parameters • Default values • AC_BE (Best effort) traffic • RTS/CTS • Option 1: Off • Option 2: On • Aggregation • MPDU: max 20 • MSDU: max 2 • Block Acknowledgement • Enabled Klaus Doppler, Nokia

15. Additional simulation results • Additional information recommended to provide, e.g.: • results to indicate how the user throughputs and MCS were distributed • user throughput CDF curves in addition to area throughput and 5 percentile of CDF numbers • MCS fluctuation histogram for a given STA or AP throughout the simulation • Example illustration of thethroughputs: • Black dots are APs • Colors indicate average throughputs of the terminals Klaus Doppler, Nokia

16. Summary • 5 percentile of user throughput cumulative distribution function and area throughput are proposed as metrics to quantify the gains for HEW enhancements • The requirements of the simulation scenarios are defined • New simulation scenario is proposed for dense apartment building use case as outlined in slides 11-14 Klaus Doppler, Nokia

17. Appendix Klaus Doppler, Nokia

18. Mobile video drives mobile data traffic • Video is dominant application • Netflix in HD currently uses 7Mbps* • Video is moving towards 4k (4x1080p) and 8k (16x1080p) • Increasing shareof TVs with Wi-Fi support** * https://support.netflix.com/en/node/8731 ** 4 out of 10 top selling TVs on Amazon.com April 22, 2013 Klaus Doppler, Nokia

19. Dense apartment building Pre-Conditions Each apartment has Wi-Fi network deployed to access internet and cloud services. In each apartment up to 3 users stream concurrently video content from the network and up to 50% of the networks are active. At the same time each of the active Wi-Fi networks is used by 2 users for web browsing Environment Building with 100 apartments. One AP in each apartment of 10mx10m randomly positioned. 5 STA per AP randomly positioned in the apartment. Applications Cloud based applications supporting video streaming with 8k resolution. Video requirements are: ~112Mbps per STA (16x1080P), delay is < 200ms, 1.0E-3 PER. The application is able to buffer up to 2s of the content to avoid interruptions of the service, allowing relaxed delay requirements Web browsing requirements for Social Networking are: ~20Mbps, PER 1e-3, delay<50ms, 1.0E-3 PER 150 active video users and 100 active web browsing users in the building with an aggregate data rate requirement of 18.8Gbps in the building. The service requirements should be met for 98% of the users in the building. Traffic Conditions Strong interference from overlapping networks (neighboring apartments, and outdoor Wi-Fi network). Multiple video display are operational simultaneously. Use Case User starts cloud video service on a fixed or mobile device with 8k display. The cloud service streams the video in 8k format. Klaus Doppler, Nokia