  The different functions of a leader node in Ad hoc networks, particularly in
Wireless Sensor Networks (WSNs) and Internet of Things (IoT) include generation
of keys for encryption/decryption, finding a node with minimum energy or node
located in an extreme side of the network. One essential application of IoT is
to monitor any dangerous, sensitive or non-accessible site. Such type of
application requires the election of a leader located on the extreme left of
the network. Indeed, one can then use any leader election (LE) algorithm to
find this node, and then start the process of finding its boundary nodes.
However, the chosen algorithm must be fault-tolerant and robust since the
detection of a node failure under such circumstances becomes impossible. This
paper surveys the most significant work performed in this direction, highlights
the challenges and proposes possible extensions.
