Table 4 Analysis of predefined and prediction based slot allocation
MAC protocol | Data reliability | Energy consumption | Remarks |
|---|---|---|---|
EF-MAC [43] | Low | High | Higher delay and lower data reliability have been noticed during contention of multiple nodes to access channel. This scheme is not suitable to transmit emergency data of more than one sensor at a time. In addition, it does not focus on low and high threshold values of vital signs |
AE-MAC [44] | Low | High | Retransmission of the lost packets degrades data reliability. Sensors consume more energy in the waiting state for a beacon to receive from MN which is not suitable for emergency data |
I-MAC [45] | Low | High | Nodes consume a higher energy during the waiting period to transmit data in their own turns because the master node locks the services of other slave nodes which are not suitable in case of emergency data |
HD-MAC [46] | Average | Low | Allocation of the slot is based on the heartbeat in the predefined time unit. This protocol is not suitable for life-threatening vital signs due to the long waiting period whereas the body coordinator cannot decide the slot allocation process between two vital signs |