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Pathloss Model Considerations for 802.11ah. Authors:. Date: November 7, 2011. November 2011. Abstract.
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Pathloss Model Considerations for 802.11ah Authors: Date: November 7, 2011 Klaus Doppler, Nokia
November 2011 Abstract • Currently proposed channel and pathloss models (doc.: IEEE 802.11-11/0883r0) includes a placeholder for an outdoor STA-STA pathloss model. This contribution reviews outdoor STA-STA pathloss models for urban environments in literature and proposes a STA-STA pathloss model.
STA-STA pathloss models in urban environment Very few pathloss model and measurement results for STA-STA link in urban environment available • Z. Wang, E.K. Tameh, A. R. Nix, “Statistical Peer-to-Peer Channel Models for Outdoor Urban Environments at 2GHz and 5GHz”, VTC Fall, 2004 • J. R. Hampton, N. M. Merheb, W. L. Lain, D. E. Paunil, R. M. Shuford,and W. T. Kasch, “Urban propagation measurements for ground based communication in the military UHF band,” IEEE Trans. Antennas and Propagat., vol. 54, no. 2, pp. 644–654, Feb. 2006. • K. Konstantinos, S. Kang, T. Brown and C. Tzaras, ”Measurement and modelling of the propagation channel between low-height terminals”, IET Microw. Antennas Propag., 2011, Vol. 5, Iss. 4, pp. 412–418 Klaus Doppler, Nokia
Pathloss model summary • [1] PL_NLOS = 4.01+ 10*5.86 log10 (d in m) (f=2GHz)PL_LOS = 31.48 + 10*2 log10(d in m) (f=900MHz) • [2] Model needs explicit modeling of streets and fewer measurements compared to 1. However, their measurements also suggest a pathloss exponent of 6-7 in NLOS case (only few measurements) • [3] PL_NLOS (h_STA=1.5m, f=900MHz) = 16.90 + 42.4*log10(d in m) The model in [3] is based on measurements and the model in [1] has been derived from a ray-tracing model Klaus Doppler, Nokia
Frequency scaling 2GHz 900MHz for [1] • The Path-loss model in [1] can be converted to frequency range 450 – 900 MHz by applying different frequency dependence coefficients in the range 20 – 35 dB per decade specified for frequency ranges 0.45 – 1.5, 1.5 –2.0 and 2.0 – 6.0 GHz separately. (See Table 4-1. in [4]) • Pathloss for urban scenario decreases 10.18dB from 2GHz to 900MHz • PL_NLOS = -6.17+ 58.6 log10 (d in m) Klaus Doppler, Nokia
Pathloss model comparison • 20-50dB difference at a distance of 1km when using Macro AP-STA pathloss model compared to STA-STA models in urban scenario • 10-35dB difference at distance of 1km when compared to Pico AP-STA pathloss model • Crossover between STA-STA models at 16m • [3] too close to pico? Klaus Doppler, Nokia
Conclusion • Include one of the following two options in the channel model document section 3.2 (outdoor pathloss model for D2D) • The antenna height is assumed 1.5m and the path loss in [dB] is given by the formula Option 1: PL= 16.90 + 42.4*log10(d) [3]Option 2: PL = -6.17 + 58.6*log10(d) [1]where d is in meters and the RF carrier is assumed at 900MHz. The above formulas represent the average path loss. Deviation around this average to account for shadowing should be modelled by adding a random Gaussian variable with zero mean and a standard deviation of 7.5dB. Klaus Doppler, Nokia
Strawpoll Option 1: --- Yes --- No --- Abstain Option 2: --- Yes --- No --- Abstain Klaus Doppler, Nokia
Motion (select option based on strawpoll result) • Include the following text in the channel model document section 3.2 (outdoor pathloss model for D2D) • The antenna height is assumed 1.5m and the path loss in [dB] is given by the formula Option 1: PL= 16.90 + 42.4*log10(d) [3]Option 2: PL = -6.17 + 58.6*log10(d) [1]where d is in meters and the RF carrier is assumed at 900MHz. The above formulas represent the average path loss. Deviation around this average to account for shadowing should be modelled by adding a random Gaussian variable with zero mean and a standard deviation of 7.5dB. • --- Yes --- No --- Abstain Klaus Doppler, Nokia
References • Z. Wang, E.K. Tameh, A. R. Nix, “Statistical Peer-to-Peer Channel Models for Outdoor Urban Environments at 2GHz and 5GHz”, VTC Fall, 2004 • J. R. Hampton, N. M. Merheb, W. L. Lain, D. E. Paunil, R. M. Shuford,and W. T. Kasch, “Urban propagation measurements for ground based communication in the military UHF band,” IEEE Trans. Antennas and Propagat., vol. 54, no. 2, pp. 644–654, Feb. 2006. • K. Konstantinos, S. Kang, T. Brown and C. Tzaras, ”Measurement and modelling of the propagation channel between low-height terminals”, IET Microw. Antennas Propag., 2011, Vol. 5, Iss. 4, pp. 412–418 • WINNER+ D5., WINNER+ Final Channel Models, June 2010 Klaus Doppler, Nokia