# A Comprehensive Review on Network Protocol Design for Autonomic Internet of Things
## 3 Review of Protocol Designs
### Protocol Designs for MAC Layer  
Most research that is related to the design of the MAC layer protocol in WSN, MANET, and IoT aim to obtain the maximum energy saving from the communication protocol. This is because the MAC protocol controls the operation of the radio module, which typically spends most of the energy in a node. Energy saving in the MAC layer can be achieved through the duty cycle adjustment of the radio module, by periodically turning \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Autonomic Properties**} & \multicolumn{6}{c}{**IoT Challenges Addressed**} \\ \cline{2-6}  & **Resource-Constraint** & **Heterogeneity** & **Mobility** & **Scalability** & **Security, Privacy, Trust** \\ \hline Self-configuration & & ✓ & & ✓ & \\ Self-healing & ✓ & & ✓ & & \\ Self-organization & ✓ & ✓ & ✓ & ✓ & \\ Self-adaptation & ✓ & ✓ & ✓ & & \\ Self-optimization & ✓ & ✓ & ✓ & ✓ & \\ Self-protection & & & & & ✓ \\ Self-energy-awareness & ✓ & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Autonomic properties address challenges in IoT. Figure 3: Autonomic properties for IoT network. on-off so that the radio has a low duty cycle without degrading the performance of data communication. The advancement of technology development has introduced the use of energy harvester modules that are able to take energy from the sources in surrounding environment, e.g., solar, wind, vibration, and even from the RF waves in the air. The harvested energy can be used to recharge the battery of the IoT node. Thus, it will extend the lifetime of nodes and the networks. Furthermore, it makes it possible to achieve continuous operation of the node, because the energy required to operate can be sufficiently provided by the energy harvested from the surrounding environment. This will support the self-energy-awareness property for the autonomic IoT network. MAC protocol design for network with energy harvesting capability is not only to support the network lifetime, but also to optimize the performance of data communication. The amount of energy consumed is made equal to the amount of energy gained, so that all the harvested energy can be exploited for the optimum performance of data communication. This energy balance condition is called Energy Neutral Operation (ENO). A node is expected to run for an optimum performance of data communication by taking care of its energy state on ENO. Thus, the more energy harvested from the energy harvesting activity, the better the performance of the network. Therefore, some new protocol design for the MAC layer are proposed in order to adjust the MAC duty cycle to dynamically maximize the network lifetime and the data communication performance. [PERSON] in [8] conducted a study of the MAC protocol design for energy harvesting WSN. Protocols evaluated include On-Demand MAC (OD-MAC), MAC Energy Harvesting (EH-MAC), QoS-Aware Energy Efficient MAC (QAEE-MAC), and Energy Harvesting Receiver Initiated MAC (ERI-MAC). It was concluded that the design of these protocols are inspired by the receiver-initiated architecture. Nevertheless, every protocol design has its own characteristic, operating principle, and trade-off. 1. OD-MAC [PERSON] and [PERSON] in [9] proposed the On-Demand MAC (OD-MAC) protocol for multi-hop energy harvesting WSNs, with the objective that every node can individually adjust the energy consumption by adjusting the duty cycle of the radio module to achieve the maximum performance of data communication. In OD-MAC protocol, a node that is ready to receive and forward the data will send a beacon packet to all nodes within range to indicate its readiness. The transmitting nodes should wait for the beacon before starting the data transfer. To reduce wasted energy and end-to-end delay due to a long waiting for beacon period, OD-MAC implements an opportunistic forwarding mechanism. In this mechanism, a list of beacon senders in the previous period is stored and compared to a list of potential forwarder nodes, which are determined by the routing protocol.