Page 59 - ITU Journal: Volume 2, No. 1 - Special issue - Propagation modelling for advanced future radio systems - Challenges for a congested radio spectrum
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ITU Journal: ICT Discoveries, Vol. 2(1), December 2019




              20                                                      ⋅10 −2
                                                   RTS              1
                                                                                                    RTS (VC)
                                                  DACM
              15                                                   0.8                              RTS (Melb)
                                                                                                  Simulated results
                                                                                                     DACM
               (    m )  10                                            (   m )  0.6
              5                                                    0.4
                                                                   0.2
              0
                                                                    0
                0      0.2     0.4     0.6    0.8      1            −180 −135 −90 −45    0   45   90   135  180
                                     
                                    m                                                   (degree)
                                                                                      m
                          (a) ℳ = 2,       = 2 GHz
                                                                            (a) Veri ication on    m ,       = 2 GHz
              40
                                                   RTS             20
                                                   DACM                                             RTS (VC)
              30                                                                                    RTS (Melb)
                                                                   15                             Simulated results
                                                                                                     DACM
               (    m )  20                                          (    m )  10
              10
                                                                    5
               0
                0      0.2     0.4     0.6     0.8     1            0  0     0.2     0.4    0.6     0.8      1
                                      m
                                                                                           
                                                                                          m
                         (b) ℳ = 3,       = 28 GHz
                                                                         (b) Veri ication on    m , ℳ = 3,       = 28 GHz
                 Fig. 7 – Examples of the curve  itting for   (   m ).
                                                                 Fig. 8 – Examples of the channel model veri ication on    m and    m .
          tion. For the latter method, we simulate the channel fol-  ability of the cluster number if ℳ ≤ 3, but these clus-
          lowing Algorithm 1. The receiver number is also    and  ters are more concentrated at the LoS direction, and the
          the simulation follows the steps in section 7. A compari-  power distribution is more uneven. Future works can be
          son of these verifying cases, RTS (VC), RTS (Melb), simu-  extended from the 2D model to a 3D air-to-ground chan-
          lated model and the channel model can be found in Fig. 8.  nel model, which brings more interest to the elevation an-
          In both of the sub- igures, the scattered dots are the veri-  gle. Also, the clustering algorithm and the modeling of the
           ication results, and the colors, red, yellow and green rep-  root mean square delay will be studied to make the DACM
          resent the RTS in a virtual city, the RTS in Melbourne CBD  more completed.
          and the numerical results respectively. The solid blue line
          is the proposed directional channel model. The carrier  REFERENCES
          frequencies are 2 GHz for Fig. 8(a) and 28 GHz for Fig.
          8(b). The three veri ication cases match the model very  [1] NGMN Alliance, “NGMN 5G white paper,” accessed
          well in both  igures. Actually, we have veri ied every case,  2019-07-17. [Online]. Available:  https://www.
          including    ,    conditioned by each ℳ at two frequen-   ngmn.org/work-programme/5g-white-paper.html
                   m
                      m
          cies. All the cases have shown a high level of matching.
          However, only two examples are depicted in this paper.  [2] Z. Li, K. Magowe, A. Giorgetti, and S. Kandeepan,
                                                                    “Blind localization of primary users with sectorial
                                                                    antennas,” in IEEE International Conference on Com-
          9.  CONCLUSION
                                                                    munications Workshops (ICC Workshops), Kansas
          In this paper, we presented a statistical clustering DACM  City, MO, USA, May 2018, pp. 1–6.
          for a general urban scenario. It can bene it the directional
          wireless network design, optimization and utilization in  [3] R. T. Rakesh, G. Das, and D. Sen, “An analytical model
          substance since the channel features can be estimated by  for millimeter wave outdoor directional non-line-of-
          merely a few distance-independent probability distribu-   sight channels,” in IEEE International Conference on
          tion parameters. The model is proposed in three key as-   Communications (ICC), Paris, France, May 2017, pp.
          pects, the number of clusters, the cluster center distribu-  1–6.
          tion and the cluster power ratio distribution at two car-
          rier frequencies, 2 GHz and 28 GHz. We have concluded  [4] M. Sha i, J. Zhang, H. Tataria, A. F. Molisch, S. Sun, T. S.
          that for both frequencies, these three parameters share   Rappaport, F. Tufvesson, S. Wu, and K. Kitao, “Mi-
          similar features but with notable differences. Compared   crowave vs. millimeter-wave propagation channels:
          with 2 GHz, 28 GHz tends to bring relatively equal prob-  Key differences and impact on 5G cellular systems,”





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