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Modeling of additional channel loss in dense WLAN environments

Modeling of additional channel loss in dense WLAN environments. Date: 2014-03-17. Authors:. Abstract. This presentation gives set of considerations on how to model additional channel loss due to human-body blockage we could experience especially in super-dense Wi-Fi environments.

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Modeling of additional channel loss in dense WLAN environments

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  1. Modeling of additional channel loss in dense WLAN environments Date: 2014-03-17 Authors: Minho Cheong (NEWRACOM)

  2. Abstract • This presentation gives set of considerations on how to model additional channel loss due to human-body blockage we could experience especially in super-dense Wi-Fi environments. Minho Cheong (NEWRACOM)

  3. Need of Supplements to Current Model • High density of STAs [1] • such as usage model 4a “Super-dense Urban Street - public access and cellular offload” Man. United’s Street Parade PSY’s Performance Outdoor Street Supporting in Word Cup 2002 Minho Cheong (NEWRACOM)

  4. Need of Supplements to Current Model • Highdensity scenarios [2] • 1a-Stadium: High density of users (0.5users/m²), inter-AP distance between 12 and 20 meters. • 1b-Airport/trains: Each AP serves 120 users in a 200m2 area (0.6 users/m²). The inter-AP distance is in the range of 15~20m. Single/multiple operators. • 1c- Exhibition halls: Each AP serves 100 users in a 100m2(1.0 user/ m²) area. The inter-AP distance is in the range of 5~10m. • 1d- Shopping malls: High density of users and high density of APs (undefined user/ m², but similar to “1c-Exhibition hall”) • 1e-Education: Dense STAs (40~60 STAs) in one classroom with one AP. Class room size is ~ 300 m² (0.2 user/ m²). Minho Cheong (NEWRACOM)

  5. Need of Supplements to Current Model • Highdensity scenarios [2] • 2a-Wireless office: Typical distances between STAs and AP in the room are < 50m. 20-30 STAs per AP . Max. user/ m² =30/(3.14*50^2)= 0.04 user/ m² • 3a-Dense apartment building: Building with 100 apartments. One AP in each apartment of 10mx10m randomly positioned. 5 STA per AP randomly positioned in the apartment. Max. user/ m² = 0.01 user/ m² • 4a-Super-dense urban street: The inter-AP distance is in the range of 20-50m. STA distribution density is about 0.5 user/ m2. In specific city squares, public events gather even higher densities 1.0 user/m² and inter-AP distance is in the range of 10-20m. Minho Cheong (NEWRACOM)

  6. Additional Path-loss due to Human Body Blockage [2] • In super-dense scenarios, in addition to general indoor (from 802.11n/ac channel model) or outdoor (from WINNER or ITU model), we need to consider the following environments as well AP My STA (smart phone) Minho Cheong (NEWRACOM)

  7. Additional Path-loss due to Human Body Blockage [2] • Blockage effect due to head-to-hand (purple in slide 6) • Whenever a person watches his smart-phone in super-dense environments, his own head is likely to block the link to AP many times, which has been a problem even in nowadays • Blockage effect due to other people (red in slide 6) • In most of HEW usage models, many people are very crowded within a limited area with super high density more than 0.5 person/m2 or 1.0 person/m2. • In these environments, we can hardly expect an LOS link between AP and STA due to blockage effect from other human bodies, which seems to require additional path loss Minho Cheong (NEWRACOM)

  8. Additional Path-loss due to Human Body Blockage [2] • Possible Supplements originally suggested before • Path loss = Path loss (current model) + delta (constant) • Add an additive (delta) due to human blockage to the current indoor & outdoor channel model specifically in super-dense environments • Work to do in the future • Need to measure & investigate the statistics of increased path loss due to human body blockage in Wi-Fi super-dense environments • According to indoor or outdoor • According to density of STAs • According to location of AP (3 dimensional) Minho Cheong (NEWRACOM)

  9. Measurement of Signal Strength Variation • Measurement spot: Seoul Express Bus terminal (indoor) • According to population density (all the other conditions same) • at 0.05 people/m2, 0.25 people/m2, 0.5 people/m2 • Measured signal power, noise power and SNR in a time-average • During several seconds (a population density can be preserved) Minho Cheong (NEWRACOM)

  10. Observations from the Measurement • Differently from our original expectations, • Additional channel loss in super-dense environments seems to be logarithm-linearly proportional to the population density Minho Cheong (NEWRACOM)

  11. Observations from the Measurement (2) Minho Cheong (NEWRACOM)

  12. Temporary Conclusions • Supplements to additional channel loss due to human-blockage effect in super dense Wi-Fi environments • Logarithmic-linearly proposal to the population density with a threshold as in slide 11. • For values of α, β and γ , enough number of measurements campaigns & related statistical analysis (such as linear regression) may be needed. • Values of α, β and γ may be dependent on indoor/outdoor, 3-dimensional deployment directions of AP • We expect more measurement campaigns by other companies (for multiple Wi-Fi environments) to check the conclusions Minho Cheong (NEWRACOM)

  13. References • [1] 11-09-0161-02-00ac-802-11ac-usage-model-document[2] 11-13-1113-00-0hew-channel-modeling-for-dense-Wi-Fi-environments Minho Cheong (NEWRACOM)

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