mly, and provides different rate and delay (in term of Tn in our model) performance. The transmit power of MBS, PBS, and FBS is set to Max-SINR Max-SINR NS-Prior NS-Prior LESS-DL LESS-DL Number of BSs Number of BSs 0.035 Max-SINR NS-Prior LESS-DL 0.025 0.015 Number of BSs Figure 9.8 Comparisons of handoff performance for the four handoff mechanisms with different number of BSs. (a) Handoff cost, (b) number of handoffs, and (c) outage probability of UEs. 9.2 Smart Handoff Policy Design for RAN Slicing 46, 30, and 20 dBm, respectively [13]. All the BSs share a 20 MHz bandwidth, and allocate them to the deployed NSs based on the NS QoS provisioning. UEs are randomly distributed in the area with different rate and delay requirements. In the following, we examine the performance of the proposed LESS handoff mechanism. In the first experiment, we compare the handoff cost, the number of handoffs, and the UE outage probability for the four handoff mechanisms when the number of BSs varies from 10 to 40 as shown in Figure 9.9. As expected, we find that the handoff cost of the two learning based mechanisms LESS and LESS-DL is much lower than that of the other two traditional mechanisms shown in Figure 9.9a. In particular, when compared with Max-SINR, NS-Prior, and LESS-DL, the handoff cost gain of LESS is about 51%, 40%, and 10%, respectively when the number of BS is 25. From Figure 9.9b, we can see that LESS achieves the smallest num- ber of handoffs, while the number of handoffs in LESS-DL is higher than that in NS-Prior due to the lack of data gathered from the LESS-DS policy. Finally, in terms of UE outage probability, Figure 9.9c shows that NS-Prior achieves a performance as good as LESS due to the prior consideration of NS service provisioning. 10 000 Max-SINR NS-Prior LESS-DL Max-SINR NS-Prior LESS-DL Number of UEs Number of UEs 0.035 Max-SINR NS-Prior 0.025 LESS-DL 0.015 Number of UEs Figure 9.9 Comparisons of handoff performance for the four handoff mechanisms with different number of UEs. (a) Handoff cost, (b) num