1. CHANNEL MODEL for INFOSTATIONS  Our first measurements  Andrej Domazetovic, WINLAB – April, 27

2. OUTLINE  Reminder: Friis free space equation  Reminder: Short range 2-ray propagation model  Estimation of the Ricean K-factor  Measurement 1 - fixed antennas  Measurement 2 - one antenna moving

3. Friis free space equation Source: [] Rappaport - Wireless Communications The formula is a valid predictor for P r for d which are in the far-field of the transmitting antenna - Fraunhofer region i.e. when inductive and electrostatic fields become negligible and only radiation field remains d f =2D 2 /, d f >>D and d f >> For f c = 5.3 GHz and the antenna size D = 7 cm d f =17.31 cm, d f >> 7 cm and d f >>5.66 cm (1)

4. Short range 2-ray propagation model Source: [] Rappaport - Wireless Communications

5. Characterize the complex signal path gain of the narrowband wireless channel as Estimation of the Ricean K factor Relate the equation to the two moments that can be estimated from the measurements of received power versus time The second moment is the rms fluctuation of G about G true. Source: [] Greenstein et. al - Moment method estimation of the Ricean K factor

6. Estimation of the Ricean K factor Under the assumption that the v(t) is complex Gaussian, zero mean, this can be written as: Source: [] Greenstein et. al - Moment method estimation of the Ricean K factor If we can estimate the left-hand side of 1 and 2 from the data, then we have two equations with two quantities that we need. And finally, the Ricean K-factor is:

7. Measurement 1 - Fixed antennas

8. Results of measurements

11. Measurement 2 - one antenna is moving

12. Results of measurements