## 5 Performance Analysis
### Simulation Results and Discussions
As a result, the fake packets have less significant effect on the EED performance of the protocol. The Pha protocol has significantly low EED because the protocol employs a simple routing algorithm with short and fixed routing paths. Figure 9a also shows the impact of adding a second level phantom node routing on the EED of the PhaP and PhaT protocols. The PhaP has a slightly longer EED than ProbR. The increase in EED is controlled by the strategic location of the \(P_{ring}\) which guarantees that the directed random-walk routing is directed towards the sink node. The PhaT has considerably lower EED than the TreeR. However, the EED of PhaT is significantly high. The EED of PhaT can be up to 3 times the EED of the traditional Pha protocol which employs only one level of phantom node routing. The long EED is mainly due to the designated location of the phantom nodes which results in elongated routing paths. Packets are first routed to the near network border regions before they are routed to the sink node. These results demonstrate that the PhaP and PhaT protocols incur some tradeoffs between privacy protection and the EED performance. Figure 9b shows the EED performance of the protocols at a fixed source-sink distance of 40 hops. The experiment scenarios included multiple source nodes. 100 packets were sent from each source node to the sink node at varied source packet rate from 1 to 7 packet/second. The figure shows that EED of all the protocols increases with the increase in source packet rate. This is due to the fact that as more packets are generated per second, the probability of packet collision, packet loss, and packet retransmission events is increased. When packet retransmission events occur, the EED is significantly increased. The EED for the TreeR protocol  
increases at a higher rate due to the presence of a considerable amount of fake packets which increase the probability of packet collision events. The EED of ProbR protocol increases at a slower rate because the protocol distributes only one fake source packet at a time period. There is no fake source packet distribution in the PhaT and PhaP protocols. Consequently, the EED of the protocols increases at a slower rate. In summary, the analysis results have demonstrated that factors such as the location of fake packet sources, location of phantom nodes, source packet generation rate, source-sink distance, and the amount of distributed fake packets can present significant impact on the SLP protection, energy consumption, PDR, and EED performance of the protocols. The TreeR protocol which positions the fake packet sources near the network border guarantees more obfuscating routing paths with strong SLP protection than the ProbR protocol which locates the fake packet sources near the sink node. The proposed PhaT protocol positions the phantom nodes in the near network border regions. Subsequently, it guarantees strong SLP protection than the PhaP protocol which positions the phantom nodes in the phantom ring located at some distance from the sink node. However, the TreeR and PhaT protocols incur relatively  
Figure 8: Packet delivery ratio (PDR) of the protocols. (**a**) PDR against varied source–sink distance. (**b**) PDR against varied source packet rate. high energy consumption, low PDR and long EED. The TreeR protocol distributes a considerable amount of fake packets in the network. As a result, it achieves significantly higher SLP protection than the ProbR protocol which distributes only one fake packet at a time. All the analyzed protocols offer lower SLP protection when the source packet generation rate is increased. Longer source-sink distance increases the complexity of the adversary tracing back attack which results in higher degree of SLP protection for all the protocols. By eliminating the fake packet traffic in the network, the proposed PhaT and PhaP protocols achieve strong SLP protection with controlled energy consumption, PDR, and EED.