# Conceptual Framework for Future WSN-MAC Protocol to Achieve Energy Consumption Enhancement
## 3 State-of-the-Art Approaches for MAC-Protocols Optimization
### General Approaches
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Reference Paper** & **Approach** & **Type** & **Contribution** & **Results** \\ \hline
[29] & Sensor-MAC (S-MAC) & Synch-TMDA & \
\begin{tabular}{c} Propose the periodic \\ sleeping of nodes in \\ channel \\ signaling message passing \\ \end{tabular} &
\begin{tabular}{c} Reduces \\ contention \\ latency and saves energy \\ \end{tabular} \\ \hline
[30] & \begin{tabular}{c} S-MAC \\ protocol \\ \end{tabular} & Asynch-CSMA & \
\begin{tabular}{c} Converting its duty cycle \\ to adaptive based on the \\ non-occurrence of \\ activation for a time \\ threshold TA \\ \end{tabular} &
\begin{tabular}{c} Describes the \\ limitations of \\ existing S-MAC \\ \end{tabular} \\ \hline
[31] & \begin{tabular}{c} ADMC-MAC \\ \end{tabular} & Synch-TMDA & \
\begin{tabular}{c} Improves data \\ transmission performance \\ based on traffic conditions \\ by taking into account the \\ size of the node queue and \\ improving the \\ energy-efficient \\ performance \\ \end{tabular} &
\begin{tabular}{c} ADMC-MAC \\ enhances the \\ residual energy saving \\ \end{tabular} \\ \hline
[32] & \begin{tabular}{c} Timeout-MAC \\ (T-MAC) \\ \end{tabular} & Asynch-CSMA & \
\begin{tabular}{c} Enables adaptive duty \\ cycle active/sleep based on \\ listening for time period \\ TA and sleep if no event \\ has occurred \\ \end{tabular} &
\begin{tabular}{c} Reduces energy and \\ minimizes collisions \\ \end{tabular} \\ \hline
[33] & \begin{tabular}{c} Hybrid MAC Protocol \\ using a Scheduling \\ based dynamic \\ Sleeping \\ \end{tabular} & Synch-TMDA & \
\begin{tabular}{c} Enabling the scheduling \\ table of nodes’ sleep/wake \\ up time and dividing the \\ channel into a set of TDMA \\ slots where some slots are \\ provided for the contention \\ of sub-nodes using \\ CSMA/CA \\ \end{tabular} &
\begin{tabular}{c} Improves the \\ network throughput and \\ enhances energy \\ conservation \\ \end{tabular} \\ \hline
[34] & \begin{tabular}{c} Zero collision MAC \\ (ZC-MAC) \\ \end{tabular} & Asynch-CSMA & \
\begin{tabular}{c} Zero collisions based on a \\ medium decomposition to \\ a pre-defined number of \\ slots of the same size as the \\ number of nodes \\ considering the slots that \\ collided in the \\ previous cycles \\ \end{tabular} &
\begin{tabular}{c} Zero collisions both \\ CSMA and TDMA at high \\ and low loads \\ \end{tabular} \\ \hline
[35] & \begin{tabular}{c} Designated \\ learning-MAC \\ \end{tabular} & Synch-TMDA & \
\begin{tabular}{c} Learning the probability of \\ selecting slots for \\ transmission based on \\ success and collision \\ \end{tabular} &
\begin{tabular}{c} Reduces the \\ number of \\ collisions \\ \end{tabular} \\ \hline
[36] & \begin{tabular}{c} Modified CSMA/CA \\ \end{tabular} & Asynch-CSMA & \
\begin{tabular}{c} Enabling deterministic \\ back-off after successful \\ transmission \\ \end{tabular} &
\begin{tabular}{c} Reduces the \\ number of \\ collisions \\ \end{tabular} \\ \hline \hline \end{tabular}
\end{table} 
Table 1: General approaches for the MAC protocol.