## 3 Proposed Method  
In the standard geographic routing protocol, the sensor nodes are able to obtain their own geographic location and store the location of the sink. Each sensor node calculates the distance according to its location and the location of the sink and then selects the nearest neighboring node to the sink as the next hop. The minimum number of node hops is found by such a routing protocol, which results in lower latency and energy consumption, and it does not require flooding to obtain a path, making it an efficient, simple and scalable routing protocol [31].  
In this paper, we first divide the monitoring area of size \(S\times S\) into two parts, the inner area and the outer area, the inner area is of size \(\frac{\xi}{3}\times\frac{\xi}{3}\), which is the center area of the monitoring area and the sink is allowed to move only within this range, and the outer area is the residual part of the monitoring area after removing the inner area, and this division of the area is proved to be suitable by the researchers [25]. Figure 1 shows the effect of the monitoring area after the division. The outer area and inner area use different routing protocols, the outer area uses the improved geographic routing protocol [25], while the inner area uses the tree-based routing protocol [25], which fully balances the energy  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Protocol** & **Method** & **Advantage** & **Disadvantage** \\ \hline FC-CRAs [9] & Combining clustering & Low energy & Single hop \\ D2 CRP [10] & Combining clustering & High lifetime & Energy imbalance \\ ESCVAD [11] & Combining clustering & High lifetime & Single hop \\ PPO & & & High PDR & High overhead \\
[12] MADRL [13] & Deep learning & Low overhead & Energy imbalance \\ RFLQGeo [14] & Deep learning & Low overhead & Energy imbalance \\ RR [15] RESMR [16] & Ring routing & High lifetime & High delay \\ DGRP & & & \\
[17] HESTOR [18] & Ring routing & Low delay & Energy imbalance \\ MSGR [19] VGB [20] & Grid structure & Low energy & Low PDR \\ CESMA-MTRS [21] & Grid structure & Low delay and high & Do not support \\ STTD [22] & & PDR & mobile sink \\ MCDM [23] & Mobile sink & Energy balance & High latency \\ EEB [24] & Mobile sink & Energy balance & Low PDR \\ RTG [25] & Mobile sink & High lifetime and low & Low PDR \\ AMSG [26] & Mobile sink & High lifetime and & Low PDR \\ EPSO [27] UDMC [28] & & & No routing protocols \\ OPT [29] GRNN [30] & & & and no \\ \hline \hline \end{tabular}
\end{table}
Table 1: Summary of previous works.  
of the outer area and inner area. Based on this, we propose energy-efficient and highly reliable routing (ERG) based on geographic location, which possesses a link detection and repair scheme that largely increases the packet delivery rate and throughput. Finally, we combine routing protocol with coverage control technique to propose energy-efficient and highly reliable geographic routing based on node collaborative scheduling (ERG-NCS), which greatly improves the coverage rate and network lifetime, further increases the packet delivery rate and reduces the network latency compared to other routing algorithms based on disk-based greedy scheduling algorithm (DGS).