## 4 Simulation And Analysis
### Analysis of Experimental Results  
In this experiment, we mainly pay attention to the impact of the cache space and number of nodes on the performance of various routing algorithms. In big data and 5G network environments, due to the large amount of transmitted data between mobile devices, the cache space of a node becomes a crucial index to measure the performance of routing strategies in OSNs. In addition, defined by the number of nodes and mobile pattern, the network topology has also been an essential consideration in the data transmission process. Figure 6: Weight value distribution for social features of mobile users. Firstly, we investigate the impact of the cache space and number of mobile devices on delivery ratio. As shown in Figure 7, with the increase of the cache space and number of nodes, the delivery ratio from these five routing algorithms generally maintains a slow upward trend, and FPRDM scheme shows a slight enhancement as compared with other four routing protocols. In particular, from Figure 7d, when \(N=600\) and \(C=40\) Mb, the delivery ratio from FPRDM is about 0.88, which is the highest value this algorithm shows. Moreover, from Figure 7a, when \(N=100\) and \(C=25\) Mb, the delivery ratio from the FCNS routing protocol exceeds that from FPRDM for only the one time. As shown in Figure 7, the delivery ratio of the ICMT routing algorithm is always in the middle degree, while the traditional routing approaches Epidemic and Spray and Wait present a relatively low delivery ratio all the time. This is because these methods only roughly control the number of message replications or data packages, but do not pay attention to the life cycle time of the message or changes in network topology. When selecting a suitable relay node, the Epidemic routing algorithm adopts the flooding model to widely spread data packages in the network, so the large number of message duplicates circulating in the networks may promote the increase of delivery ratio, and cause a sharp rise in costs and delays. ICMT, Spray and Wait, and FCNS employ data management, encountering history, and fuzzy control to make a more accurate decision on message routing and forwarding, respectively. However, these approaches still transmit messages to multiple unrelated nodes which do not participate in the data dissemination process. The FPRDM scheme first performs a classification identification of nodes, and then allocates a suitable weight to each social characteristic of message user and determines three different grades of membership functions (high, medium, and low)  
Figure 7: Performance comparison of delivery ratio with various cache spaces and various number of nodes. (**a**) \(N=100\). (**b**) \(N=200\). (**c**) \(N=400\). (**d**) \(N=600\). for the quantization vector, thereby selecting the appropriate relay nodes through the process of a defuzzifier component. For this reason, a relatively high delivery ratio with an average of 0.8 could be presented from the FPRDM scheme. Furthermore, Figure 8 displays the performance comparison of these five routing algorithms in terms of the average end-to-end delay with various cache spaces and various number of nodes. On the whole, the Epidemic routing algorithm consistently exhibits the highest end-to-end delay among these strategies due to the flooding dissemination of messages. Additionally, because the Spray and Wait and ICMT routing protocols respectively employ two-phases and a cooperative mechanism to reduce the number of messages appropriately, they present an average end-to-end delay of 300 s when enlarging the cache space of mobile devices from 10 to 40 Mb, which is within the middle range among these approaches. As shown in Figure 8a-d, the average end-to-end delay from the FPRDM algorithm is always the lowest, while that from the FCNS method is the second lowest. It should be noted that the average end-to-end delay from FPRDM reaches the lowest value of 68 s when \(N=100\) in Figure 8a.