Page 91 - ITU Journal Future and evolving technologies Volume 2 (2021), Issue 4 – AI and machine learning solutions in 5G and future networks
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ITU Journal on Future and Evolving Technologies, Volume 2 (2021), Issue 4




                                                               As  shown,  the  proposed  ML  mechanisms  provide  general
                                                               accurate predictions; most of the error values are in the
                                                               range of 0 to 10 Mbps. This means that, even in the pres‑
                                                               ence of outliers, the predictions provided by the ML mod‑
                                                               els are suitable for a signi icant percentage of the deploy‑
                                                               ments. The accuracy of the different models proposed by
                                                               ATARI, STC, and NET INTELS can be further observed in
                                                               Table  4,  which  shows  the  percentage  of  the  throughput
                                                               predictions for STAs achieving an error below 10 Mbps.

                                                               Table 4 – Percentage of per‑STA predictions achieving <10 Mbps error.
                                                               Information is provided for ATARI, STC, and NET INTELS results.

                                                                               test1   test2   test3    test4
                                                                    ATARI     36.97%  55.81%   67.01%  77.40%
                                                                     STC      55.97%  56.27%   56.74%  60.67%
                                                                  NET INTELS  38.09%  42.15%   44.01%  49.77%
          Fig. 7 – Mean absolute error obtained by each team, for each of the test
          scenarios of the data set.  The aggregate throughput of all the BSSs is
          considered.                                          For completeness, Fig. 9 shows the actual throughput
                                                               achieved by STAs in all the test scenarios. As shown, the
          them apart from the rest.  As a result, it is able to gener‑   median is around 20 Mbps, but maximum values of up
          alize well, even for new deployments with characteristics   to 40 Mbps are also likely. Furthermore, several outliers
          unseen in the training phase.                        were noticed, leading to up to 50 Mbps in some STAs.


          Although the prediction error is high for some test sce‑
          narios,  it  is  important  to  remark  that  the  performance
          of  WLANs  applying  CB  can  be  up  to  a  few  hundreds  of
          Mbps  (especially  in  sparse  scenarios  with  low  competi‑
          tion).  To  better  illustrate  the  accuracy  of  the  proposed
          models, we now show the prediction results obtained on
          a per‑STA basis.  Notice that the following results corre‑
          spond  to  the  solutions  provided  by  three  teams  (ATARI,
          STC,  and  Net  Intels),  whose  solution  was  based  on  pre‑
          dicting the throughput of STAs, and providing the aggre‑
          gate performance afterward.  Note, as well, that the tar‑
          get of the challenge was predicting the aggregate through‑
          put in each BSS. In particular, Fig. 8 shows the histogram
          of the individual throughput predictions at STAs obtained
          across all the random test deployments.
                                                               Fig. 9 – Boxplot of the mean throughput achieved by STAs for each test
                                                               scenario.

                                                               Finally,  to  provide  some  insight  on  the  computational
                                                               needs required by the types of ML methods discussed in
                                                               this paper,  Table 5 contains the time required for train‑
                                                               ing each model used by the team Net Intels, as well as the
                                                               amount of computational resources employed. As shown,
                                                               the training times are acceptable for providing near‑real‑
                                                               time solutions.


                                                               Table 5 – Training time and computational resources used by the ML
                                                               models proposed by Net Intels.
                                                                               Training time    RAM/GPU used
                                                                ANN               349 s       8 Gb RAM / 1.3 Gb GPU
                                                                Random forest      69 s     55 Gb RAM/ No GPU usage
                                                                KNN               122 s     5.3 Gb RAM/ No GPU usage
          Fig. 8 – Histogram of the per‑STA prediction error achieved by ATARI,
          STC, and NET INTELS.







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