Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)

1. Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [Path-Loss Exponents of Ultra Wideband Signals in Line-of-Sight Environments] Date Submitted: [14 March, 2004] Source: [Shunsuke Sato and Takehiko Kobayashi] Company [UWB Technology Institute, Communications Research Laboratory / Tokyo Denki University] Address [Tokyo Denki University, 2-2 Kanda-nishiki-cho, Chiyoda-ku, Tokyo 101-8457, Japan] Voice [+81 3 5280 3839] E-Mail: [shunsuke@grace.c.dendai.ac.jp, koba@c.dendai.ac.jp] Re:[Status report of the 802.15.4a channel modeling subgroup] Abstract: [This contribution describes a new line-of-sight path loss formula for ultra wideband signals in the presence of the ground plane reflection.] Purpose: [Reports on a UWB pass loss formulafor IEEE802.15TG4a] Notice: This document has been prepared to assist the IEEE P802.15. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by P802.15. Communications Research Laboratory

2. Path-Loss Exponents ofUltra Wideband Signals in Line-of-Sight Environments Shunsuke Sato and Takehiko Kobayashi Communications Research Laboratory Tokyo Denki University Presented by Honggang Zhang, Yuko Rikuta Communications Research Laboratory Communications Research Laboratory

3. Table of contents • Background • Narrowband two-path model • Conventional UWB two-path model • Proposal of a new UWB two-path model formula • Experimental verification • Conclusion Communications Research Laboratory

4. Background Conventional UWB path-loss models • Free Space : path loss exponent = 2 • UWB Two path model [1] : • Direct wave plus reflected wave from the ground plane • Path loss exponent changes from 2 to 4 at a breakpoint • Breakpoint distance = 2 m (no reason given) • Applicable to the order of meters (?) • Another UWB two path model [2] • Breakpoint distance is not given Proposal for a new line-of-sight path loss formula of UWB signals in the presence of the ground plane reflection. Communications Research Laboratory

5. Narrowband two-path model [3] Communications Research Laboratory

6. Path-loss based on the narrowband two-path model Breakpoint hT = hR = 1 m ，g = 1 , f = p Path loss exponent changes 2 to 4 at the breakpoint Communications Research Laboratory

7. The narrowband two-path model formula Distance between the transmitting and receiving antennas x, transmitting antenna height hT, receiving antenna height hR, frequency f，velocity of the light c, and ground reflection coefficient gexp ( jf) Communications Research Laboratory

8. Breakpoint distance • The Freznel zone distance [3]: • The linear envelope with a slope of x2 intersects the line of approximation with a slope of x4 : hT = hR = 1 m Communications Research Laboratory

9. The proposed UWB two-path model formula[4] • The path loss of a UWB the integral of the CW. Distance between the transmitting and receiving antennasx , transmitting antenna heighthT, receiving antenna height hR, lowest frequency fL，highest frequency fH， velocity of the light c, and ground reflection coefficientgexp ( jf). Communications Research Laboratory

10. Predicted UWB path-loss characteristics hT= hR = 1 m, g = 1, f =p, frequency=3.1-10.6 GHz． Communications Research Laboratory

11. Dependence of fL and bandwidth fL = 3.1 GHz fL = 6.0 GHz hT =hR =1 m Communications Research Laboratory

12. Breakpoint distances and path-loss exponentscalculated by the proposed formula fL = 3.1 GHz , hT= hR = 1 m Communications Research Laboratory

13. Breakpoint distance is the most appropriate: fL=3.1 GHz Communications Research Laboratory

14. Experimental setup x Bandwidth：3.1-10.6 GHz, Polarization：Vertical Communications Research Laboratory

15. Experimental verification Communications Research Laboratory

16. Conclusion • Derived a new UWB two-path model formula • The path-loss exponent of UWB signals changes from approximately 2 to 4 at the breakpoint. • Breakpoint distance = , • Confirmed by an indoor experiment Communications Research Laboratory

17. References [1] ITU-R Doc. 1-8/047-E, March 28, 2003. [2] ITU-R Doc, 1-8/32-E, Jan 16, 2003. [3] W. C. Y. Lee, Mobile Communications Engineering, 2nd ed., pp. 116-120, McGraw-Hill, New York, 1982. [4] S. Sato and T. Kobayashi, “Path-loss exponents of ultra wideband signals in line-of-sight environments,” 2004 IEEE International Symposium on Spread Spectrum Techniques and Applications, Sydney, Australia, Aug. 30-Sept. 2, 2004, submitted. Communications Research Laboratory