## 6 Simulation Experiments and Performance Analysis
### Results Analyses  
Figure 14 shows the performance of the different SI-based routing protocols in terms of the packet delivery ratio (PDR). PDR is referred to as the ratio of the total number of packets transmitted and received at the sink node or base station (BS). The total number of transmitted packets at the BS may be lower than or equal to those generated at the sensor nodes in the network. The results show that IEEABR outperformed the other SI-based protocols. The results show that initially, at a very minimal node density, IEEABR performed optimally by delivering approximately 90% of all the generated packets in the network at the BS via the DCVs, followed by Bee-Sensor-C, which achieved approximately 87% PDR, while EBAR and FF both achieved 80% PDR. As the node density gradually increased, IEEABR maintained optimal performance compared to the other protocols and achieved 95% PDR at a maximum node density of 1000. However, the performance of Bee-Sensor declined as the node density gradually increased and was outperformed by EBAR, which achieved 90% PDR at a maximum node density of 1000, followed by Bee-Sensor, with 86% PDR at a node density of 1000. The high performance of IEEABR is significant for critical large-scale sensor network applications running in smart cities, which require high data delivery performance. This implies that waste management operations employing IEEABR strategies can achieve high delivery performance to meet the requirements of the smart city ecosystem. Figure 15 shows the performance of the SI-based protocols in terms of throughput. Throughput refers to the overall number of packets that are successfully delivered at the sink node or BS within one second. In general, IEEABR outperformed the other routing protocols, followed by EBAR, Bee-Sensor-C, and FF. An important observation in Figure 14 is the performance decline in throughput values with increasing node density. Ordinarily, throughput is improved by increasing the number of sensor nodes in the network. However, increasing the node density in the network should be synchronous with the number of DCVs sent into the network. However, due to the issue of network complexity and cost, increasing the number of DCVs as the node density increases is counterproductive, requiring an optimal number of DCVs to maintain network stability. Hence, the decline in throughput values exhibited by IEEABR, Bee-Sensor-C, and FF with increasing node density is normal. Figure 16 shows the network operational lifetime prediction of the routing protocols. The network lifetime is the extended lifetime of the network for various rounds in a given time. As can be observed, IEEABR outperformed the other protocols, with the longest lifetime. All the routing protocols achieved good network lifetime, with IEEABR achieving the longest network lifetime, followed by Bee-Sensor, EBAR, and FF. This evaluation is very significant, as it shows the efficacy of SI-based techniques in saving energy and prolonging  
Figure 19: Comparison based on latency. the network lifetime. This makes such techniques suitable for SC applications such as waste management and target-tracking applications. Applications employing SI-based techniques for data collection are able to minimize energy consumption at the sensor nodes since data collection within short ranges is enabled, and protocol overheads are transferred to the DCVs, thereby saving energy at the sensor nodes, optimizing their energy consumption and increasing the network lifetime. Figures 17 and 18 show the performance in terms of the average energy consumption and energy efficiency, respectively. The energy consumption of the sensor nodes refers to the total energy expended by all sensor nodes in the network in transmitting their data to the DCVs. In this case, IEEABR outperformed the other protocols for these metrics by achieving a low energy consumption, even at a maximum node density, and achieving the highest energy efficiency, followed by Bee-Sensor-C, EBAR, and FF.