  Energy Efficiency in wireless sensor networks is an important topic in which
the nodes rely on battery power, and efficient energy usage is a key issue for
sensitive applications that require long working times. This stimulates many
scientists at all levels of communication protocols Medium Access Control (MAC)
who control the use of the wireless transmitter and receiver unit to create new
protocols. Many protocols were suggested that primarily take energy efficiency
as the primary objective of sustaining the function of the network for as long
as possible into account with different objectives for wireless sensor
networks. This paper will look at some of these energy efficiency protocols.
