## 2 Literature Review
It was projected that the intermediate node would be far from the actual source node, making it difficult for the attackers to learn about the real source from the intermediate node chosen. To provide source location privacy at the network (global) level, the information in the packet is subsequently combined with that of other packets using a network mixing ring (NMR) in the following routing phase. In the end, selected nodes on the mixing ring forward the data packet to the SINK node. This scheme shows the same latency and power consumption as PFS, but its privacy level is higher. Additional routing strategies were proposed by [PERSON] and [PERSON] [45; 46] to improve this routing scheme for enhancing privacy. More random walk-based SLP solutions have been proposed by different researchers with the aim of improving existing ones in terms of privacy. To safeguard both the source node and the sink, a source location privacy (SLP) mechanism was created by [PERSON] et al. in [25]. Even though the article proposed four solutions, we consider only the forward random walk (FRW) strategy since the other three strategies are based on fake packets or fake sources, which belong to the different categories of SLP-preserving approaches we consider in this work. Each node in the forward random walk technique randomly chooses a neighbor node that is nearer to the BS when relaying a packet. This guarantees packet convergence at the BS. Since every packet's destination is the BS, the nodes located in its sensing range send packets straight there. A forward random walk appears to provide a certain degree of privacy when the source node is situated far from the base station. However, significant privacy concerns emerge when the source node is in close proximity to the BS (base station). For improving existing random walk-based routing protocols, directed random walk was proposed by [PERSON] et al. in [47]. In a directed random walk, each node splits its neighbors into two groups that are opposite one another. Instead of employing a pure random walk, the next hop is chosen randomly from two groups to reach an intermediate node. Then, from the intermediate node, the next hop is chosen from the opposite group. It seems that the suggested scheme may offer some enhancements in the security period. However, the routing path lacks the necessary diversity to confound potential adversaries, and there is a notable absence of consideration for the network's overall lifetime. The research in [28] segregates the network into sectors. The selection of the sector is made randomly for each new packet that is sent from the source node. Once the packets reach that intended sector, they travel toward the BS. Sectors that are closest to the source are given lower priority than those that are away from the source. However, this technique exhibits weaker privacy due to its inadequately varied and unpredictable routing path, which fails to effectively mislead potential adversaries. Furthermore, the relationship between privacy and network lifespan has not been investigated. [PERSON] et al. proposed another routing scheme in [18] that divides a network into quadrants with the aim of hiding the real source of information from a local adversary. When an asset is detected, a source node sends a packet at random to a predetermined proxy node that is chosen and situated in the quadrant next to its own. The proxy node then uses a forward random walk to deliver the packet to the BS. As the predefined proxy nodes in this work are found in only two quadrants, it may be easier for an adversary to find them as the packets are coming from only those quadrants. Furthermore, since the same set of nodes (from those quadrants) are utilized to deliver the packets to the BS, the NLT may also be impacted. The article [29] developed a phantom node-based scheme. In this article, the source node chooses a limited number of network nodes to behave as phantom nodes that are not inside a circle encircling the source node whenever an asset is detected.