  The advancement in cyber-physical systems has opened a new way in disaster
management and rescue operations. The usage of UAVs is very promising in this
context. UAVs, mainly quadcopters, are small in size and their payload capacity
is limited. A single UAV can not traverse the whole area. Hence multiple UAVs
or swarms of UAVs come into the picture managing the entire payload in a
modular and equiproportional manner. In this work we have explored a vast topic
related to UAVs. Among the UAVs quadcopter is the main focus. We explored the
types of quadcopters, their flying strategy,their communication protocols,
architecture and controlling techniques, followed by the swarm behaviour in
nature and UAVs. Swarm behaviour and a few swarm optimization algorithms has
been explored here. Swarm architecture and communication in between swarm UAV
networks also got a special attention in our work. In disaster management the
UAV swarm network must have to search a large area. And for this proper path
planning algorithm is required. We have discussed the existing path planning
algorithm, their advantages and disadvantages in great detail. Formation
maintenance of the swarm network is an important issue which has been explored
through leader-follower technique. The wireless path loss model has been
modelled using friis and ground ray reflection model. Using this path loss
models we have managed to create the link budget and simulate the variation of
communication link performance with the variation of distance.
