## 5 Numerical Results
The peak traffic offered to any sub-area is distributed according to a log-normal distribution [20] whose mean value depends on the SI considered, the considered region (business and residential) and the traffic direction (upstream and downstream). The average peak traffic normalized to the average peak traffic during the Peak Hour Interval (PHI) is reported in Figure 4 for the business and residential regions [23; 24]. We assume that the upstream traffic is 70% of the downstream one. We also denote with \(A_{o,b}\) and \(A_{o,r}\) the average peak traffic in the PHI for business and residential regions, respectively. Finally, the parameters of the log-normal distribution are chosen so as to guarantee for the distribution matching of both the forecast average peak traffic and a typical standard deviation equal to 0.25 [20]. To support the user traffic, the number of RRUs and RBSs installed in each sub-area are dimensioned according to the procedure illustrated in [2]. Let \(\gamma\) denote the ratio of the number \(n_{RRU}^{x}\) (\(x\in\{b,r\}\)) of RRUs to the total number \(n_{RRU}^{x}+n_{RBS}^{x}\) (\(x\in\{b,r\}\)) of radio stations. To achieve the required flexibility and cost efficiency, eleven different line bit rates of CPRI flows (Options 1-10 and 7a) have been defined [25]. As an example, we consider only Options 2-3, 5 and 7 that allow for the transport of radio samples of signals usually generated in mobile systems. We assume a radio bandwidth equal to 20 MHz and \(Q=5\) possible configurations for any RRU where the configuration \(S_{0}\) corresponds to the switched off RRU. In particular the active number of antennas is \(n_{0}=0\), \(n_{1}=1\), \(n_{2}=2\), \(n_{3}=4\) and \(n_{4}=8\) for the configurations \(S_{0}\), \(S_{1}\), \(S_{2}\), \(S_{3}\), and \(S_{4}\), respectively. The capacity of an RRU for these values of antennas is \(C_{0}^{RRU}=0\), \(C_{1}^{RRU}=75\) Mbps, \(C_{2}^{RRU}=150\) Mbps, \(C_{3}^{RRU}=300\) Mbps and \(C_{4}^{RRU}=600\) Mbps to which correspond the CPRI bit rates of the flow generated/received \(f_{0}^{CPRI}=0\), \(f_{1}^{CPRI}=1.2288\) Gbps, \(f_{2}^{CPRI}=2.4576\) Gbps, \(f_{3}^{CPRI}=4.8152\) Gbps and \(f_{4}^{CPRI}=9.8304\) Gbps [22]. An ODU2 container can carry a maximum number of \(\eta_{0}^{CPRI}=0\), \(\eta_{1}^{CPRI}=8\), \(\eta_{2}^{CPRI}=4\), \(\eta_{3}^{CPRI}=2\) and \(\eta_{4}^{CPRI}=1\) CPRI flows of the antenna configurations \(S_{0}\), \(S_{1}\), \(S_{2}\), \(S_{3}\), and \(S_{4}\) respectively [22]. The number of active antennas, the RRU capacities, the CPRI bit-rates and the maximum number of CPRI flows carried in one ODU2 for configurations \(S_{1}\), \(S_{2}\), \(S_{3}\), and \(S_{4}\) are reported in Table 3. Finally, RBSs are also employed with capacity \(C_{RBS}=600\) Mbps. Figure 4: Normalized traffic profile for business and residential sub-area. We consider optical rings in which each wavelength carries a 100 Gbps flow that leads to have \(\eta^{\lambda}=10\). Shortest paths are selected for routing the traffic demands between any tuple AS-CO (CO-AS). We evaluate the effectiveness of the proposed network reconfiguration solution in Figures 5 and 6 where we report the total number of wavelengths used and the number of wavelengths used in each optical ring, respectively, as a function of the used RRU percentage \(\gamma\). The average peak traffic in the PHI is chosen equal to \(A_{o,b}=26\) Gbps and \(A_{o,r}=16\) Gbps for business and residential sub-area, respectively. In particular, the values shown in Figure 5 measure the cost of the solutions considered. We also compare the dimensioning results achieved by applying the proposed dynamic resource allocation solution to a static one in which the optical rings are statically dimensioned that is when the network provides the sufficient bandwidth to carry the traffic flows generated by the RRUs and RBSs in full load condition with all of the antennas active.