tailieunhanh - Mobil Ad Hoc Networks Protocol Design Part 8

Tham khảo tài liệu 'mobil ad hoc networks protocol design part 8', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 272 Mobile Ad-Hoc Networks Protocol Design Location Networks QDV Target A Mobile WiMAX1 Mobile WiMAX1 UMTS MobileWiMAX2 B WLAN1 Mobile WiMAX2 UMTS Mobile WiMAX2 C wlan1 wlan1 UMTS Mobile WiMAX2 D WLAN2 wlan2 UMTS Mobile WiMAX2 E WLAN3 wlan3 UMTS Table 3. QDVs of Candidate Networks llx - wn II min x - wi II 23 i 1 . 6 where the index n denotes the wining neuron number and wn wn1 wn2 . wn30 is the weight vector to the nth neuron. Weight adjustment in the kth step of the winner uses the learning rule as Zurada 1992 wJj 1 Wn ak x - w 24 wk 1 wk for i n 25 where ak is a learning constant at the kth step. In the simulation an area in which there are three WLANs two WiMAX and a UMTS is considered as shown in Fig. 6. We first evaluate the performance under number of users ranging from 100-2100 as seen in Figs. 8-10. Figure 8 illustrates that the proposed PRSS FQDA approach yields the fewest number of vertical handoffs in comparison to the PRSS HT and SOM approaches. Meanwhile the numbers of vertical handoffs of all approaches increase when the number of users increases. The number of vertical handoffs using PRSS FQDA is gently increases as the number of users increases but that of PRSS HT and SOM obviously increase. In Fig. 9 the dropping probability of PRSS FQDA is fewest since it determines the optimal network regarding to the network condition whether it satisfies the preference of users and has a strong RSS as well. Accordingly this yield the fewest GoS using the PRSS FQDA approach as shown in Fig. 10. The performance metrics under different arrival rates ranging from 6 to 16 are demonstrated in Figs. 11-13. The simulation results shown in Figs. 11-13 reveal that the proposed PRSS FQDA approach outperforms the PRSS HT and SOM approaches in terms of the number of vertical handoffs handoff call dropping probability and GoS. In Fig. 11 the number of handoffs increases gradually as the mean