# Improving Response Time for Crowd Management in Hajj
## 2 Related Work  
FANET has become very popular after drones, commercial intervention and usage. Now, in many applications such as monitoring infrastructure, civil works, agriculture monitoring, mass crowd monitoring and many others, drones are used to collect multimedia data. FANETs can be described as a group of Unmanned Aerial Vehicles, which communicate without any access point. In contrast, at least one among the group acts as the server or satellite. These are automated systems, which don't involve any human input for their basic operations [5]. All the network activity, including the discovery of its topology or the sending of messages, is carried out by the nodes that integrate it. This type of network has an arbitrary topology. The main consequence of this mobility is that links can be formed and broken frequently, which implies that the network must be self-organized. The path between an origin and a specific destination that crosses several intermediate nodes can be modified. When this happens, the network must re-organize itself to establish a new path in the least possible time. This functionality requires that each member of the network will forward data on behalf of other members who act as a router. The nodes of a FANET network have components or associated factors which are considered when carrying out an efficient routing. These factors include auto-configuration, bandwidth, distance, energy, routing path, partitions/unions, speed, and variation in the routing path. FANET is based on the peer-to-peer (P2P) concept, where peers are mostly UAVs. [PERSON] et al. [6] presented the usage of drones in railways to monitor the situation, issues early warnings, and some decision-support applications. Their study and framework help in automatically checking the railway infrastructure parameters. This monitoring helps provide early warnings, any threats related to faults and security, or any natural hazards or intruder attacks. In railway applications, drones help with three major applications, namely structural monitoring, environmental security monitoring, and physical security monitoring. Another exciting application area is agriculture monitoring using drones. The drone's technology helps farmers optimize the resources required for agriculture, like the amount of water required, and to monitor pests and other diseases. It helps the farmer to target the precision in harvesting and fertilizing. The drones help with collecting the data from the fields, its processing analysis, and management. The drones also play an active role in agriculture applications like interventions in the irrigation and fertilizers of crops [7]. Farmers utilize the drones in many ways, like counting the number of fruits on every tree, the leaf area index measurement, the computation of Normalized Difference Vegetation Index (NDVI), identifying plant diseases, and remote sensing for water management and irrigation control applications, so that the farmer can apply the chemical, and pesticides on time [8]. Drones are also used in monitoring disasters. FANETs are deployed to the area to encounter the situation as, most of the time, humans cannot reach the remote location due to obstacles [9]. Drones are also beneficial in search and rescue operations where all the conventional mobile networks have failed or are temporarily unavailable. FANETs can search for hostages and help humans reach those areas which are physically impossible to reach themselves [7]. With the use of FANETs, the monitoring and analysis of the construction area are easy. Humans can verify the quality, progress, and work condition remotely using FANETs [9]. [PERSON] et al. [10] discussed the challenges of FANET. The first challenge belongs to signal transmission because most of the directional antennas are omnidirectional, and usingthem in drones may not be very efficient in terms of quality and energy consumption. The new antenna developed with beamforming technology [11] is more effective and efficient in drones.