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Human Body Shadowing at 28 GHz

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Abstract

It is well known that human body shadowing is a significant propagation effect in indoor communications especially at frequencies higher than 10 GHz. Thus, in this work, human body shadowing in directive short range channel is measured at 28 GHz. A distance of 10 m between the transmitting antenna and the receiving one is used in the measurement campaign. Two body orientations are used in this study. Four persons have participated in the measurement campaign as objects. Shadowing results are given for single person case and two person case. It is shown that maximum body shadowing occurs when the body is near to the transmitting or receiving antenna. Minimum shadowing occurs at almost the half of the distance between the transmitting and receiving antennas. It is shown that, body shadowing loss is low when the body is not in the center line between the transmitting and receiving antennas. At an antenna height of 1.2 m and 1.4 m, height and weight of the person under study affect the shadowing loss. In general, higher person and heavier person give a rise to higher shadowing loss. Crossing the line between the transmitting antenna and the receiving one, body shadowing loss of 10–36 dB is noticed. For the first orientation, shadowing loss due to two persons reaches to 36.5 dB when one of them moving along the line between the transmitting antenna and the receiving one and the other is at 5 ms from the transmitting antenna. A shadowing loss of 50.1 dB is observed when the third person is at 9.5 m from the transmitting antenna a d the fourth one is at 0.5 m from the transmitting antenna.

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References

  1. 1.

    Sato, K., & Manabe, T. (1998). Estimation of propagation-path visibility for indoor wireless LAN systems under shadowing condition by human bodies. In Proceedings of the IEEE VTC, Ottawa, Canada, May 1998 (Vol. 3, pp. 2109–2113).

  2. 2.

    Kashiwagi, I., Taga, T., & Imai, T. (2010). Time-varying path-shadowing model for indoor populated environments. IEEE Vehicular Technology Society,59, 16–28.

  3. 3.

    Fujii T., & Ohta, Y. (2007). Dynamic channel modeling for static mobile terminals in indoor NLOS environments. In IEEE VTC2007-Fall.

  4. 4.

    Fujii, T., & Ohta, Y. (2010). Physical channel modeling for static mobile terminals in indoor environments. In Procedings of the EuCAP2010.

  5. 5.

    Kara, A. (2009). Human body shadowing variability in short-range indoor radio links at 3–11 GHz band. International Journal of Electronics,96(2), 205–211.

  6. 6.

    Irahhauten, Z., Dacuna, J., Janssen, G. J. M., & Nikookar, H. (2005). UWB channel measurements and results for wireless personal area networks application. In Proceedings of the European conference on wireless technology, Paris, France (pp. 189–192).

  7. 7.

    Pradubphon, A., Promwong, S., Chamchoy, M., Supanakoon, P., & Takada, J. (2004). Characterization of body shadowing effects on ultra-wideband propagation channel. In ICCAS2004 (pp. 219–222).

  8. 8.

    Zhang, R., Cai, L., He, S., Dong, X., & Pan, J. (2009). Modeling, validation and performance evaluation of body shadowing effect in ultra-wideband networks. Physical Communications,2(4), 237–247.

  9. 9.

    Ayadi, M., & Ben Zineb, A. (2014). Body shadowing and furniture effects for accuracy improvement of indoor wave propagation models. IEEE Transactions on Wireless Communications,13(11), 5999–6006.

  10. 10.

    Chen, X., Tian, L., Tang, P., & Zhang, J. (2016). Modelling of human body shadowing based on 28 GHz indoor measurement results. In 2016 IEEE 84th vehicular technology conference (VTC-Fall).

  11. 11.

    Ye, X., Yin, X., Yan, H., & Yuste, A. P. Millimeter wave channel models for human passing through a line-of-sight path. URSI Organization.

  12. 12.

    Karadimas, P., Allen, B., & Smith, P. (2013). Human body shadowing characterization for 60-GHz indoor short-range wireless links. IEEE Antennas and Wireless Propagation Letters,12, 1650–1653.

  13. 13.

    Rappaport, T. S., Maccartney, G. R., Samimi, M. K., & Sun, S. (2015). Wideband millimeter-wave propagation measurements and channel models for future wireless communication system design. IEEE Transactions on Communications,63(9), 3029–3056.

  14. 14.

    Sulyman, A. I., Alwarafy, A., MacCartney, G. R., Rappaport, T. S., & Alsanie, A. (2016). Directional radio propagation path loss models for millimeter-wave wireless networks in the 28-, 60-, and 73-GHz bands. IEEE Transactions on Wireless Communications,15(10), 6939–6947.

  15. 15.

    Rappaport, T. S., Xing, Y., MacCartney, G. R., Molisch, A. F., Mellios, E., & Zhang, J. (2017). Overview of millimeter wave communications for fifth-generation (5G) wireless networks. IEEE Transactions on Antennas and Propagation,65, 6213–6230.

  16. 16.

    Sun, S., Rappaport, T. S., Shafi, M., Tang, P., Zhang, J., & Smith, P. J. (2018). Propagation models and performance evaluation for 5G millimeter-wave bands. IEEE Transactions on Vehicular Technology,67, 8422–8439.

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Correspondence to Bazil Taha Ahmed.

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Appendix

Appendix

When a person exists in the line between the transmitting antenna and the receiving one, the rays that contribute in the received signal are the attenuated direct ray with three diffracted rays, two of them form the lateral part of the body and the third one the diffracted ray from the head (Fig. 14).

Fig. 14
figure14

Attenuated direct ray with two diffracted rays for an object at the central line where the diffracted ray from the head is not depicted (first body orientation case)

When a person exists out of the line between the transmitting antenna and the receiving one, the rays that contribute in the received signal are, the direct ray with two diffracted rays from the lateral part of the body (Fig. 15).

Fig. 15
figure15

Direct ray with two diffracted rays for an object with lateral displacement (first body orientation case)

Due to the geometry of the scenario at which measurements have been carried out and the antenna used, the maximum value that the system can measure with a small error is limited to a given value whatever high is the dynamic range of the measurement system. Figure 16 depicts the measured loss versus the possible body shadowing loss. The lower limit represents the case when the residual scenario resultant ray and the ray due to the human being shadowing are in phase. The upper limit represents the case when the residual scenario resultant ray and the ray due to the human being shadowing are out of phase. It can be seen that at a measured loss of 60 dB, possible body shadowing is 59.72 dB up to 60.3 dB. Also, it can be seen that at a measured loss of 70 dB, possible body shadowing is 67.8 dB up to 74.7 dB. Such high shadowing loss occurs with multi body obstructing the LoS ray.

Fig. 16
figure16

Measured loss and possible measurement error versus the measured loss

The worst-case (occurs when the sidewall reflection and the ceil reflection are in phase) limit of measurements whatever high is the dynamic range of the measurement system is almost 65 dB (with 1 dB error). A more practical limit could be 68 dB.

A measure to increase the scenario measurement limit is to use absorbing material around the specular reflection point. It is worth mentioning that multi-reflection has insignificant effect on the scenario measurement limit (Fig. 16).

Figure 17 presents the maximum limit of body shadowing loss as a function of the dynamic range of the measurement system and the scenario loss limit due to the geometry of the scenario and the used antennas. Here maximum limit of 77 dB of body shadowing loss is shown. A more practical upper limit could be 70 dB.

Fig. 17
figure17

Maximum limit of body shadowing loss as a function of the dynamic range of the measurement system and the scenario loss limit

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Ahmed, B.T. Human Body Shadowing at 28 GHz. Wireless Pers Commun 110, 621–635 (2020). https://doi.org/10.1007/s11277-019-06746-8

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Keywords

  • Body shadowing
  • Directive antennas
  • Directive channel