volume | PIER Journals

Abstract

Due to the increased use of indoor wireless networks and the concern about human exposure to radio-frequency sources, exposure awareness has increased during recent years. However, current-day network planners rarely take into account electricfield strengths when designing networks. Therefore in this paper, a heuristic indoor network planner for exposure calculation and optimization of wireless networks is developed, jointly optimizing coverage and exposure, for homogeneous or heterogeneous networks. The implemented exposure models are validated by simulations and measurements. As a first novel optimization feature, networks are designed that do not exceed a user-defined electric-field strength value in the building. The influence of the maximally allowed field strength, based on norms in different countries, and the assumed minimal separation between the access point and the human are investigated for a typical office building. As a second feature, a novel heuristic exposure minimization algorithm is presented and applied to a wireless homogeneous WiFi and a heterogeneous WiFi-LTE femtocell network, using a new metric that is simple but accurate. Field strength reductions of a factor 3 to 6 compared to traditional network deployments are achieved and a more homogeneous distribution of the observed field values on the building floor is obtained. Also, the influence of the throughput requirement on the field strength distribution on the building floor is assessed. Moreover, it is shown that exposure minimization is more effective for high than for low throughput requirements and that high field values are more reduced than low field values.

1. Ji, Z., B.-H. Li, H.-X. Wang, H.-Y. Chen, and T. K. Sarkar, "Efficient ray-tracing methods for propagation prediction for indoor wireless communications," IEEE Antennas and Propagation Magazine , Vol. 43, No. 2, 41-49, April 2001. Google Scholar

2. Torres, R., L. Valle, M. Domingo, and M. Diez, "CINDOOR: an engineering tool for planning and design of wireless systems in enclosed spaces," IEEE Antennas and Propagation Magazine, Vol. 41, No. 4, 11-22, September 1999.
doi:10.1109/74.789733 Google Scholar

3. Wlfle, G., R. Wahl, P. Wertz, P. Wildbolz, and F. Landstorfer, "Dominant path prediction model for indoor scenarios," German Microwave Conference, Ulm, Germany, April 2005. Google Scholar

4. Dimitriou, A. G., S. Siachalou, A. Bletsas and J. N. Sahalos, "An efficient propagation model for automatic planning of indoor wireless networks," 3rd European Conference on Antennas and Propagation, Barcelona, Spain, April 12-16, 2010. Google Scholar

5. Sebastiao, P., R. Tome, F. Velez, A. Grilo, F. Cercas, D. Robalo, A. Rodrigues, F. F. Varela, and C. X. P. Nunes, "WLAN planning tool: A techno-economic perspective," COST 2100 TD(09)935 Meeting, Vienna, Austria, September 28-30, 2009. Google Scholar

6. Phaiboon, S., "An empirically based path loss model for indoor wireless channels in laboratory building," IEEE Region 10 Conference on Computers, Communications, Control and Power Engineering, Vol. 2, 1020-1023, October 2002. Google Scholar

7. Keenan, J. M. and A. J. Motley, "Radio coverage in buildings," BTSJ, Vol. 8, No. 1, 19-24, January 1990. Google Scholar

8. Plets, D., W. Joseph, K. Vanhecke, E. Tanghe, and L. Martens, "Coverage prediction and optimization algorithms for indoor environments," EURASIP Journal on Wireless Communications and Networking, Special Issue on Radio Propagation, Channel Mod-eling, and Wireless, , Vol. 1, Channel Simulation Tools for Heterogeneous Networking Evaluation, 2012, http://jwcn.eurasipjournals. com/content/2012/1/123. Google Scholar

9. Plets, D., W. Joseph, E. D. Poorter, L. Martens, and I. Moerman, "Concept and framework of a self-regulating symbiotic network," EURASIP Journal on Wireless Communications and Networking, Vol. 2012, No. 340, 2012, http://jwcn.eurasipjournals.com/conte-nt/2012/1/340. Google Scholar

10. Deruyck, M., E. Tanghe, W. Joseph, and L. Martens, "Modelling and optimization of power consumption in wireless access networks," Elsevier Computer Communications (Special Issue: European Wireless 2010), Vol. 34, No. 17, 2036-2046, November 2011. Google Scholar

11. Joseph, W., L. Verloock, F. Goeminne, G. Vermeeren, and L. Martens, "Assessment of RF exposures from emerging wireless communication technologies in different environments," Health Physics, Vol. 102, No. 2, 161-172, February 2012.
doi:10.1097/HP.0b013e31822f8e39 Google Scholar

12. IEEE Std C95.1 "IEEE standard for safety levels with respect to human exposure to radio frequency electromagnetic fields, 3 kHz to 300 GHz,", 1999. Google Scholar

13. ICNIRP "Guidelines for limiting exposure to time-varying electric, magnetic, and electromagnetic fields (up to 300 GHz)," Health Physics, Vol. 74, No. 4, 494-522, April 1998. Google Scholar

14. Deruyck, M., W. Vereecken, W. Joseph, B. Lannoo, M. Pickavet, and L. Martens, "Reducing the power consumption in wireless access networks: Overview and recommendations," Progress In Electromagnetics Research, Vol. 132, 255-274, 2012. Google Scholar

15. Foster, K. R., "Radiofrequency exposure from wireless LANs using Wi-Fi technology," Health Physics, Vol. 92, 280-289, 2007.
doi:10.1097/01.HP.0000248117.74843.34 Google Scholar

16. Joseph, W., P. Frei, M. RoÄosli, G. Thuroczy, P. Gajsek, T. Trcek, J. Bolte, G. Vermeeren, E. Mohler, P. Juhsz, V. Finta, and L. Martens, "Comparison of personal radio frequency electromagnetic field exposure in different urban areas across Europe," Environmental Research, Vol. 110, No. 7, 658-663, 2010.
doi:10.1016/j.envres.2010.06.009 Google Scholar

17. Joseph, W., P. Frei, M. Roosli, G. Vermeeren, J. Bolte, G. Thuroczy, P. Gajsek, T. Trcek, E. Mohler, P. Juhasz, V. Finta, and L. Martens, "Between-country comparison of whole-body SAR from personal exposure data in urban areas," Bioelectromagnetics, Vol. 33, No. 8, 682-694, December 2012.
doi:10.1002/bem.21737 Google Scholar

18. Frei, P., E. Mohler, A. Burgi, J. Frohlich, G. Neubauer, C. Braun-Fahrlander, and M. Roosli, "A prediction model for personal radio frequency electromagnetic field exposure," Science of The Total Environment, Vol. 408, No. 1, 102-108, 2009.
doi:10.1016/j.scitotenv.2009.09.023 Google Scholar

19. Boursianis, A., P. Vanias, and T. Samaras, "Measurements for assessing the exposure from 3G femtocells," Radiation Protection Dosimetry, Vol. 150, No. 2, 158-167, 2012.
doi:10.1093/rpd/ncr398 Google Scholar

20. Perentos, N., S. Iskra, A. Faraone, R. McKenzie, G. Bit-Babik, and V. Anderson, "Exposure compliance methodologies for multiple input multiple output (MIMO) enabled networks and terminals," IEEE Transactions on Antennas and Propagation, Vol. 60, 644-653, 2012.
doi:10.1109/TAP.2011.2173453 Google Scholar

21. Russo, P., G. Cerri, and V. Vespasiani, "A numerical coefficient for evaluation of the environmental impact of electromagnetic fields radiated by base stations for mobile communications," Bioelectromagnetics, Vol. 31, 613-621, 2010.
doi:10.1002/bem.20604 Google Scholar

22. Cerri, G., R. De Leo, D. Micheli, and P. Russo, "Base-station network planning including environmental impact control," IEE Proceedings - Communications, Vol. 151, No. 3, 197-203, June 2004.
doi:10.1049/ip-com:20040146 Google Scholar

23. Koutitas, G., "Green network planning of single frequency networks," IEEE Transactions on Broadcasting, Vol. 56, No. 4, 541-550, December 2010.
doi:10.1109/TBC.2010.2056252 Google Scholar

24. Deruyck, M., W. Joseph, and L. Martens, "Power consumption model for macrocell and microcell base stations," Transactions on Emerging Telecommunication Technologies, 2012， doi:10.1002/ett.2565. Google Scholar

25. ITU-R Recommendation P.1546 "Method for point-to-area predictions for terrestrial services in the frequency range 30MHz to 3000 MHz,", 2003-2005. Google Scholar

26. Verloock, L., W. Joseph, G. Vermeeren, and L. Martens, "Procedure for assessment of general public exposure from wlan in offices and in wireless sensor network testbed," Health Physics, Vol. 9, No. 4, 628-638, 2012. Google Scholar

27. European Telecommunications Standards Institute, ETSI EN 300 328-2 v1.5.1, "Electromagnetic compatibility and Radio spectrum Matters (ERM); Wideband Transmission systems; Data transmission equipment operating in the 2.4 GHz ISM band and using spread spectrum modulation techniques; Part 2: Harmonized EN covering essential ," requirements under article 3.2 of the R&TTE Directive Edition: 1.2.1, August 2004. Google Scholar

28. Plets, D., W. Joseph, K. Vanhecke, E. Tanghe, and L. Martens, "Simple indoor path loss prediction algorithm and validation in living lab setting," Wireless Personal Communications, 1-18, 10.1007/s11277-011-0467-4, 2013, http://dx.doi.org/10.1007/s11277-011-0467-4. Google Scholar

29. International Commission on Non-ionizing Radiation Protection (ICNIRP) "Guidelines for limiting exposure to time-varying electric, magnetic, and electromagnetic fields (up to 300 GHz)," Health Physics, Vol. 74, No. 4, 494-522, April 1998. Google Scholar

30. Joseph, W., D. Pareit, G. Vermeeren, D. Naudts, L. Verloock, L. Martens, and I. Moerman, "Determination of the duty cycle of WLAN for realistic radio frequency electromagnetic field exposure assessment," Progress in Biophysics & Molecular Biology, October 2012. Google Scholar

Dr. David Plets

Dr. Wout Joseph

Dr. Kris Vanhecke

Dr. Luc Martens