## 3 O-MAC Protocol Design Goals and Architecture
### Interior Communication
#### 3.1.2 Preamble Tradeoff Validation Model  
The O-MAC uses the ODFF model, which is a tradeoff between the energy consumption and time. The ODFF comes with a short preamble that shows an improvement in the QoS and energy efficiency compared with existing lower-power listening (LPL) protocols. The LPL protocols use a long-sized preamble prior to sending the data on the channel. The long-sized preamble takes additional time to reach to other nodes. As a result, additional time and energy are consumed at non-targeted receivers. The LPL protocols also introduce an additional latency at each hop. The long preamble-enabled \begin{table}
\begin{tabular}{c c c} \hline \hline \multirow{2}{*}{**Name of the Parameter**} & \multicolumn{2}{c}{**Analytical Calculation for the**} & **Analytical Calculation** \\  & **Optimized Data Frame Format** & **for IEEE 802.15.4** \\ \hline \multirow{2}{*}{\begin{tabular}{c} Channel access time \\ Data frame transfer time \\ \end{tabular} } & \(\text{Cat}=(2^{3}-1)\times 16\times 16+8\times 16=1.92\) ms & 2.368 ms \\ \cline{1-1}  & \(T_{f}=\frac{(127+1+1+1)\times 8}{250\times 10^{3}}=4.16\) ms & 4.256 ms \\ \hline \multirow{2}{*}{\
\begin{tabular}{c} Transmission timing for \\ acknowledgement \\ \end{tabular} } & \multirow{2}{*}{\(T_{ack}=\frac{(5+1+1+1)\times 8}{250\,\times\,10^{3}}=0.256\) ms} & \multirow{2}{*}{0.352 ms} \\ \cline{1-1}  & & \\ \hline \multicolumn{1}{c}{Turnaround time} & \(0.192\) ms & 0.192 ms \\ \hline \multicolumn{1}{c}{Retry transmission time} & \(T_{retry}=48\times 0.016=0.768\) ms & 0.864 ms \\ \hline \multicolumn{1}{c}{Total access channel, frame} & \multirow{2}{*}{\(T_{ti}=1.92+4.16+0.192+\,0.256=6.528\) ms} & \multirow{2}{*}{7.168 ms} \\ \cline{1-1}  & & \\ \cline{1-1}  & & \\ \cline{1-1}  & & \\ \hline \multicolumn{1}{c}{Total access channel, frame} & \multirow{2}{*}{\(T_{tw}=1.92+4.16+0.768+1.92+4.16+0.192\)} & \multirow{2}{*}{14.656 ms} \\ \cline{1-1}  & & & \\ \cline{1-1}  & & & \\ \cline{1-1}  & & & \\ \hline \multicolumn{1}{c}{
\begin{tabular}{c} Type to send 1 MB of data \\ \end{tabular} } & \(T_{td}=\frac{2^{20}}{117}\times 8.24\,\,\,=70\,\,\,\text{s}\) & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Comparison of BN-MAC and IEEE 802.15.4 based on the data frame model. protocols have a serious problem because all of the nodes over a channel must wait until the long preamble is delivered to the targeted node. This scheme consumes additional energy at both the sender and receiver. For example, in X-MAC [21], the destination address is incorporated within each preamble, which not only increases the size but consumes additional energy and requires additional time to arrive at another node. Despite the address of a particular node having been merged into the packet, each node checks all of the preamble packets on the network. As a result, all of the nodes along the way consume time and additional energy because the sensor nodes are not intelligent. If a preamble packet is discarded by a non-intended node, then there is no possibility for the preamble to be delivered to the anticipated node. If the node is the anticipated recipient, it remains awake for the subsequent data packets. Furthermore, X-MAC is purely based on an asynchronous approach, and it does not follow the neighboring nodes' schedules. As a result, the nodes consume additional energy while waiting on the channel for the next traffic to be called, which is an idle listening problem. The reduced size of the preamble in O-MAC confirms and validates the tradeoff between time and energy. We demonstrate the processes of B-MAC [22] and WiseMAC [23] (long preamble-enabled MAC protocols), short preamble (X-MAC) and O-MAC in Figure 4. As noted above, O-MAC uses an ODFF that not only has support for a short preamble but also provides an automatic packet buffering process. Thus, it reduces the wake up time and consumes less energy.