## 2 Related Works
### Algorithms without Using Localization
In the second stage, the node chooses the next-hop sensors close to the sink with excellent link quality and high residual energy. In the final stage, the physical distance is redetermined by sending tiny messages after a specified period, resulting in increased energy consumption. Furthermore, the ETX estimator's use is not practical as it only uses one metric to measure the link quality, the packet reception rate [40; 41]. In [42], a new non-location multi-layered routing protocol (MRP) was presented using supernodes. The supernodes are linked to the sink located on the water surface, whereas the regular nodes are scattered at the water's bottom level. On the other hand, supernodes are designed with high energy and different power-level transmission. These nodes are employed for synchronization and obtaining the locations of the nodes in the network. MRP is categorized into two stages: layering and forwarding. In the first stage, supernodes broadcast beacon messages with different power-level transmissions, respectively containing the layer ID and its ID. The nodes that receive this message will assign this layer's ID and the supernodes' ID and record this information. After that, the power-level is increased and broadcasts the layer ID and supernode ID to the nodes. This procedure is repeated until all sensors are assigned with a layer and supernode ID. In the second stage, the source node sends the data packets using the layer-to-layer technique; each node receives the data packet computed, holding time based on residual energy. These nodes hold the data packet for a specific time to avoid duplicate packet transmission. If the holding time for one of the nodes is finished, it directly transmits the packet using the flooding technique to the next layer (next layer ID). All nodes that receive the same data packet discard these data. The data packet then reaches the supernode, and the supernode transmits it to the sink with maximum power transmission. To conclude, both the MRP and H2-DAB protocol employs the same layering approach. Furthermore, Hop-ID in H2-DAB and layer ID in MRP is mostly the same. MRP obtains more reliable links than H2-DAB. Nevertheless, MRP undergoes some obstacles. The supernode utilizes maximum power to broadcast the message to another supernode placed at a high level, resulting in packet collision in multiple packets transmission and requires resending the data packets by the sensor node. Therefore, it occurs in high energy consumption. Furthermore, the MRP protocol ignores the link quality parameter, which affects the packet reception rate. In this paper, the depth metric was employed to differentiate the depth level of neighbors. TM2 RP is dissimilar and valuable from DBR, EEDBR, and MRP as follows. * DBR utilizes the depth metric to choose the next hop sensor nodes, whereas EEDBR employs residual energy to choose the next-hop nodes. In contrast, TM2 RP utilizes residual energy and link quality to choose the efficient link among neighbors. * MRP utilizes only supernodes and residual energy to choose the next-hop nodes, whereas TM2 RP utilizes supernodes to create a different level and choose the next hop using residual energy and link quality to reduce the elected sensors.