The Urban Channel Model

Document Sample
The Urban Channel Model Powered By Docstoc
					   The Urban Channel Model

Electromagnetic Propagation in Urban Areas
                   Giorgio Franceschetti
           University Federico II of Napoli (Italy)
     and University of California at Los Angeles (UCLA)

 Numerical and Graphical Solvers for Urban
              Propagation
                       Daniele Riccio
           University Federico II of Napoli (Italy)

Analytical Approaches to Propagation in Urban
                   Areas
                  Massimo Franceschetti
       University of California at San Diego (UCSD)

                                                          Capri Wireless School
                                                           Sept. 13 -17, 2004
Electromagnetic Propagation in
         Urban Areas
               Giorgio Franceschetti
       University Federico II of Napoli , Italy
 and University of California at Los Angeles (UCLA)


                    Topics
          The city ensemble
          The deterministic approach
          The probabilistic approach


                                                      Capri Wireless School
                                                       Sept. 13 -17, 2004
     The city ensemble




The cities distribution may be considered
as a stochastic process, each city being
an element of this ensemble




                                       Capri Wireless School
                                        Sept. 13 -17, 2004
The Deterministic Geometrical Model
               DGM



        Buildings schematisation
        Ray tracing procedures




                                   Capri Wireless School
                                    Sept. 13 -17, 2004
     DGM cnd
Buildings schematisation




                           Capri Wireless School
                            Sept. 13 -17, 2004
   DGM cnd
Ray tracing procedures




                         Capri Wireless School
                          Sept. 13 -17, 2004
               DGM cnd


        Attractive features

Canyon effect well described
Illumination in geometrically obscured areas is
provided
Modulated signal can be accounted for



                                          Capri Wireless School
                                           Sept. 13 -17, 2004
      DGM cnd


    Limitations

Model validity
Adopted algorithm precision
Computational efficiency




                              Capri Wireless School
                               Sept. 13 -17, 2004
                                DGM cnd
              Computational efficiency exploited

                 Equation:  ni 1  ni   i  ni  ni 1 

       For i  n0  const                     ni  n0
                                                      i



stopping at iteration I, total number of equivalent sources         nI  n0
                                                                          I




                         1                                            i
                     1 i 
                                2

       For i  n0                  ,  1                          1 i
                                                        ni  n0
                                                                1
          total number of equivalent sources         n  n0 

                                                                            Capri Wireless School
                                                                             Sept. 13 -17, 2004
The Stochastic Environment Model
               SEM
Description of general features of urban
propagation, relying in a minimum number of
physically meaningful parameters

Stochastic Environment Small–scatterers Model
                    SESM

Stochastic Environment Large–scatterers Model
                    SELM

                                           Capri Wireless School
                                            Sept. 13 -17, 2004
             SEM cnd


SESM: scattering mechanism dominated
      by myriads of small scatterers
      present in the city body


SELM: probabilistic      description    of
      building     distribution    as   a
      percolative lattice


                                        Capri Wireless School
                                         Sept. 13 -17, 2004
        SEM cnd
Examples of percolative lattices




                                   Capri Wireless School
                                    Sept. 13 -17, 2004
Stochastic Environment Small–scatterers Model
                    SESM

                      Power summation issue



                           Doppler shift issue
                       1                                 
        f t, z           F   exp i t   z  vt   d 
                      2                      c           

                                   v   z
                             f t  t  
                                   c   c


                                                                   Capri Wireless School
                                                                    Sept. 13 -17, 2004
SESM cnd




           Capri Wireless School
            Sept. 13 -17, 2004
               SESM cnd

Pdf of injected photon to undergo its first hit at P(r)
                           1
             qr             exp   r 
                         4 r 2




Photons absorbed with pdf  q  r  , and scattered
around with pdf 1    q  r 

Pdf of total power absorbed at P(r) is the sum of
those lost by photons that reach P(r) after one hit,
two hits, three hits, ………

                                               Capri Wireless School
                                                Sept. 13 -17, 2004
  SESM cnd



Radio – link equation

          GA
PR  PT          C exp( br )
          4 r 2




  b  1  1    
                   2

                    




                                Capri Wireless School
                                 Sept. 13 -17, 2004
Stochastic Environment Large–scatterers Model
                   SELM




                                     Capri Wireless School
                                      Sept. 13 -17, 2004
Capri Wireless School
 Sept. 13 -17, 2004

				
DOCUMENT INFO