## 5 Results
### Bit Rate Coverage Results  
In Figure 5a,b we report the coverage for the target bit rate for group 1 and for DS direction and US direction, respectively. We have considered \(K=6\) copper pairs for each radio node and \(d_{OE}=200,400,600\) m. In the same figure, vectoring and non-vectoring case have been reported, respectively. Coverage is analyzed for the actual FttC network configuration (indicated as no OE case) and for the extended FttC network considering the two (first and second) evolution strategies illustrated in the previous Section. As expected, achievable vectoring performance always overcomes non-vectoring. In order to correctly analyze results corresponding to different \(d_{OE}\) presented in this and in the following figures it should be noted that coverage statistics for variable \(d_{OE}\) have been obtained over the distributors not connected by fiber. The percentage of this distributors is shown in Figure 4 and it decreases with \(d_{OE}\). From results in Figure 5 the first evolution strategy leads to a coverage improvement only for radio nodes close to the new Cabinet at distance \(d_{OE}\) from the old one. Results show that adoption of first strategy can be convenient only for small \(d_{OE}\) (200 m). In fact, the increase of \(d_{OE}\) leads to a reduction of the percentage of distributors connected by copper to the new Cabinet but the proportion of distributors still far from the new Cabinets increases thus leading to a performance reduction. This reduction is indicated by a relatively high percentage of distributors with small bit rates (few tens of Mbit/s) as shown by the green curves in the Figure. This inconvenience can be overcome by considering the second evolution approach where the additional Cabinet is always located in the proximity of the first distributor at distance greater than \(d_{OE}\). This leads to the (almost) invariant behavior of coverage with \(d_{OE}\) as shown in the Figure. It can be observed that, for \(d_{OE}=200\) m, the first evolution approach provides 1 Gbit/s coverage of about 80% for DS and 2 Gbit/s at 25%. Instead, with the second approach coverages of 93% and 48% are obtained for the considered two bit rates, respectively. Similar considerations can be made in the case of US direction as shown in Figure 5b. In particular a target bit rate of 400 Mbit/s can be ensured with a coverage of 82% with the first strategy and about 92% for the second strategy. The two coverage values are not so different. This is due to the most favourable propagation and reduced FEXT conditions in the case of US direction with respect to DS direction due to the lower frequency bands occupied by the US signals. In Figure 6a,b we report the sum bit rate coverage for group 1 and the other two groups for DS direction and US direction, respectively. We have considered \(K=6\) copper pairs per node and \(d_{OE}=300\) m. Results in the vectoring case are indicated with solid lines and the results in the non-vectoring case with dashed lines. Figure 5: Sum bit rate coverage for group 1, \(d_{OE}=200,400,600\) m—number of pairs assigned to each radio node \(K=6\), user activity factor \(p=0.5\), vectoring and non-vectoring: DS (**a**); US (**b**). Finally, in Figure 9a,b we study the effects of FEXT variations on the achievable sum bit rate due to the activity of wired subscribers connected to the same cable. Results are presented for the group 1, with \(K=6\), and \(d_{OE}=200\) m and for the case of DS direction and US direction, respectively, and with and without vectoring. Variable activity factors \(p\) from 0.25 to 0.75 have been considered for wired subscribers. The increase of FEXT due to increased activity of wired subscribers leads to a performance reduction causing oscillations in the available fronthauling transport capacity at the radio node.