doc.: IEEE 11-14/0113r0

Submission

Mar. 2014

Minho Cheong (NEWRACOM)Slide 1

Modeling of additional channel loss in dense WLAN environments

Date: 2014-03-17

Authors:Name Affiliations Address Phone emailMinho Cheong NEWRACOM 193 Moonjiro,

Yuseong-Gu, Daejeon, Korea

+82-42-860-5635 minho.cheong@newracom.com

Hyoung Jin Kwon NEWRACOM 193 Moonjiro, Yuseong-Gu, Daejeon, Korea

+82-42-860-1698 hj.kwon@newracom.com

Jae Seung Lee ETRI jasonlee@etri.re.kr

doc.: IEEE 11-14/0113r0

Submission

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.

Mar. 2014

Slide 2 Minho Cheong (NEWRACOM)

doc.: IEEE 11-14/0113r0

Submission

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”

Slide 3 Minho Cheong (NEWRACOM)

Street Supporting in Word Cup 2002 PSY’s Performance Outdoor Man. United’s Street Parade

Mar. 2014

doc.: IEEE 11-14/0113r0

Submission

Need of Supplements to Current Model

• High density 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).

Slide 4 Minho Cheong (NEWRACOM)

Mar. 2014

doc.: IEEE 11-14/0113r0

Submission

Need of Supplements to Current Model

• High density 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.

Slide 5 Minho Cheong (NEWRACOM)

Mar. 2014

doc.: IEEE 11-14/0113r0

Submission

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

Slide 6 Minho Cheong (NEWRACOM)

AP

My STA(smart phone)

Mar. 2014

doc.: IEEE 11-14/0113r0

Submission

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

Slide 7 Minho Cheong (NEWRACOM)

Mar. 2014

doc.: IEEE 11-14/0113r0

Submission

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)

Slide 8 Minho Cheong (NEWRACOM)

Mar. 2014

doc.: IEEE 11-14/0113r0

Submission

Measurement of Signal Strength Variation

Slide 9 Minho Cheong (NEWRACOM)

• 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)

Mar. 2014

doc.: IEEE 11-14/0113r0

Submission

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

Slide 10 Minho Cheong (NEWRACOM)

Mar. 2014

doc.: IEEE 11-14/0113r0

Submission

Observations from the Measurement (2)

Mar. 2014

Slide 11 Minho Cheong (NEWRACOM)

doc.: IEEE 11-14/0113r0

Submission

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

Mar. 2014

Slide 12 Minho Cheong (NEWRACOM)

doc.: IEEE 11-14/0113r0

Submission

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

Mar. 2014

Slide 13 Minho Cheong (NEWRACOM)