## 5 Performance Analysis
### Discussion of the Protocols  
The proposed protocols demonstrate more practical performance features than their contender ProbR and TreeR protocols. An important design issue of the proposed protocols is the additional computation load which is caused by the addition of the new second level phantom node. To reduce the computation load on the sensor node, one approach may be to introduce a new parameter called \"Forward sessions\". The parameter may be used to allow one route to forward multiple successive packets before a new route is created. This approach may reduce the computation load. However, the privacy protection level may be jeopardized. The practicality of the approach will be investigated in our future work. To minimize the EED which may be caused by the addition of the new second level phantom node in the proposed protocols, the computation of candidate second level phantom nodes is done during the network configuration phase. In PhaP, the computation of the \(P_{ring}\) is done during the network configuration phase and in PhaT the computation of \(N_{NB}\) and candidate \(npN\) is done during the network configuration phase. Furthermore, the \(P_{ring}\) is strategically positioned to ensure the packet routes are directed towards the sink node. Although the PhaT protocol incurs shorter EED than the TreeR, the EED is significantly high. One approach to improve the EED may be to introduce node offset angle routing technique during phantom node selection process. In Reference [3], it was shown that the use of node offset angle during route creation process can improve the latency of a protocol. The use of node offset angle during phantom node selection process will be investigated in our future work. Comparing the complexity of the proposed PhaT and the TreeR protocol, the complexity of the TreeR protocol is significantly high. The TreeR protocol incurs high complexity due to the computation of the diversionary routes which route fake packets. For every packet transmission from a source node, a single backbone route of the TreeR protocol may create about nine diversionary routes. Each node in a diversionary route is required to send request messages for fake packets, also to transmit and receive the fake packets. As a result, the protocol is complex. The complexity of the proposed PhaP protocol is slightly higher than the complexity of ProbR protocol mainly due to the selection of the random second level phantom node. The privacy protection of the proposed PhaT protocol improves with the increase in network size. This is mainly due to the fact that larger networks facilitate the creation of longer and highly diversified routing paths. However, the communication overhead of the PhaT protocol increases with the increase in network size. This is due to the fact that the routing paths are designed to first diverge to the near network border regions where the phantom nodes are located, from the phantom nodes the packets are routed towards the sink node. Therefore, the location of the phantom nodes must be configured according to the network size to ensure controlled communication overhead. Both PhaT and TreeR protocols work well in WSNs which locate the sink node at the center of the WSN domain.