## 2 Literature Review
### Relation between Communications and Safety in AHS
[11] discuss how robotics have contributed to mining and other domains regarding the following areas:  
* Assist workers in hazardous environments that pose health risks, such as excessive heat, dust, poisonous smoke, or hydrogen sulfide (H2S). * Fulfill labor shortages. * Provide an opportunity to increase health and safety. * Outperform humans in terms of performance. Reliable communication has a significant role in the prosperity of AHS systems. ATs can communicate via various communications with the command center to collect data from neighbors, control telemetry, and monitor the health and safety of components. Using a secure communication system, the command center can guide trucks as well as manage them to enable tracking the mining operations. It is important to note that the mining environment is the same as any other industrial environment. That is, mining operations would effectively benefit from technological advancement in communications, but they also suffer from the same vulnerabilities with some particularities pertaining to the mining environment. In particular, AHS in mining relies heavily on wireless communications that were considered unfit for industrial operation at some point. However, as stated in [8], with the industrial revolution 4.0 and the integration of CPS and IoT systems in mining (i.e., in the industry in general), communication technologies have become essential for daily operation. Indeed, an autonomous truck must maintain continuous communication with central control. Otherwise, communication failure, even for a single piece of equipment, means the whole fleet will stop running. Technically, this is called \"mine shutdown\" due to communication loss. According to [6], AHS relies entirely on wireless technology for secure production and supervisory control. As a result, a stable network infrastructure (wired and wireless) is critical to AHS operations. Since the advent of Industry 4.0, Wi-Fi technology has been an integral part of industrial operation [8]. Wireless Networks (WNs) have also opened new opportunities for business, such as easy deployment with lower cost. Despite the essential role of WNs in linking field devices and mobile assets, they face some difficulties that could affect both credibility and availability of operations. [PERSON] [6] demonstrates that AHS communications are susceptible to known attacks such as Wi-Fi De-Auth, which is a DoS assault on key operations. The authors in [7] show how existing wireless standards are insufficient to meet the demands of Industry 4.0. [PERSON] et al. [23] argue that the advent of IoT and CPS in the industrial environment have caused existing Wi-Fi standards to lose traction as they are not capable of handling dense and large-scale deployments. Signal interference, topology control in the mining environment, and signal jamming are some of the issues inherited from 802.11 standards [8]. In addition, [PERSON] et al. [24] address the relevance of wireless sensor networks (WSNs) and their capacity to improve safety as well as availability in a mining environment. The authors also highlight current challenges and how the mining industry should take advantage of WSNs. For that reason, WSNs could assist in the following areas of mining operations:  
* Localization services, especially for AHS vehicles that require high precision and low latency. * Data collection and analysis to minimize downtime that is a critical factor in extending the lifetime of an operation along with aiding in optimizing operations and achieving proactive maintenance. * Health and safety are paramount in mining industry; sensing technology may assist in gathering data from the field to monitor both employee and equipment health, especially in areas where toxic gases are present (e.g., H2S). Furthermore, proximity sensors are designed to prevent and detect obstacles along with dangerous conditions while trucks are driving in an autonomous mode, which is essential in mining operations.