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9.11
9.11
The concept of a simple correlation model for shadow fading has been widely adopted in LTE co-existence studies mostly employed in uplink case. The propagation attenuation is modelled as the product of the path loss and the shadow fading. The shadow fading is well approximated by a log-normal distribution. Let z denotes shadow fading in dB with zero mean and variance σ2. Then the shadow fading of path from one UE to the i-th BS is expressed as



                                

Unit
body zi=a*x + b*yi ,
   (Eq. 64)


where a2+b2=1 and xand yiare independent Gaussian distributed variables, both with zero mean and variance σ2.yi and yjfor are independent as well.

Figure 207 presents how to set-up the pathloss correlation in SEAMCAT (only available for OFDMA). The panel is similar for the OFDMA DL and UL.

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Figure 207: Illustration of the pathloss correlation – input parameters


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Figure 208: Illustration of the pathloss correlation principle


Thus, the correlation coefficient of the shadow fading from one UE to two different BSs, i.e., the i-th and j-th BS, is

                                                                              Image Added(Eq. 65)

 In most LTE studies,

Mathinline
bodya=b=1/√2
  is assumed ‎[10]. For cellurar systems with three-sector antennas, the shadowing correlation between sites (equivalent to BS in Omni antenna system) is of 0.5 and correlation between sectors of the same site is consequently of 1.


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