Praise for Fundamentals of WiMAX

12.6 Bibliography 427Base StationdMSFigure 12.13 The Walfish-Ikegami modelThe model is made up of three terms:PL = L fs + L rts + L msd, (12.23)where, L fs is the free-space loss, L rts is the rooftop-to-street diffraction loss, and L msd is the multiscreenloss. The model provides analytical expressions for each of the terms for a variety ofscenarios and parameter settings. For the standard NLOS case, with BS antenna height 12.5m,building height 12m, building-to-building distance 50m, width 25m, MS antenna height 1.5m,orientation 30° for all paths, and in a metropolitan center, the equation simplifies to1.5fPL = – 65.9 + 38log 10 d + 24.5 + -------- . (12.24)⎝⎛ 925⎠⎞ log10 fThis equation is recommended by the WiMAX Forum to be used for system modeling. Theuse of an additional 10dB for fading margin is also recommended with this model.The Walfish-Ikegami model also provides an expression for the urban canyon case, whichhas a LOS component between the BS and the MS. For the LOS case, the median pathlossexpression isPL = – 31.4 + 26log 10 d + 20log 10 f . (12.25)12.6 Bibliography[1] 3GPP TSG-RAN-1. Effective SIR computation for OFDM system-level simulations. Document R1-03-1370, November 2003.[2] 3GPP TSG-RAN1. System level simulation of OFDM—further considerations. Document R1-03-1303, November 2003.[3] V. Erceg, et.al. An empirically based pathloss model for wireless channels in suburban environments.IEEE Journal on Selected Areas of Communications, 17(7), July 1999.