# Accurate Energy Consumption Modeling of IEEE 802.15.4e TSCH Using Dual-Band OpenMote Hardware
## 4 Measurements
### Device State Current Consumption
#### 4.3.1 2.4 GHz CC2538 Radio  
In Table 15, the consumption values of the different device states when using the CC2538 radio, i.e., the 2.4 GHz radio, are shown. The values for the TX state were measured when the transmit power of the radio was set to 0 dBm. When the transmit power was set to 3 dBm, i.e., the current default in OpenWSN, the consumption values of the TX states are 33.04 mA and 29.01 mA, for the CPU in Active and Sleep state, respectively.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**State** & \multicolumn{2}{c}{**Duration (\(\mu\)s)**} \\ \hline  & **CC2538** & **CC1200** \\ \hline RxDataOffsetStart & 126 & 126 \\ RxDataOffset & 1567 & 1567 \\ RxDataPrepare & 38 & 676 \\ RxDataReady & 969 & 331 \\ RxDataListenStart & 17 & 58 \\ RxDataListen & 1283 & 1242 \\ RxDataStart & 17 & 15 \\ RxData & \((3+s)\times 32-17\) & \((3+s)\times 32-15\) \\ RxProc & \(198+(s\times 0.91)\) & \(488+(s\times 8.439)\) \\ Sleep & 10,706 \(-(s\times 31.09)\) & 10,416 \(-(s\times 23.561)\) \\ \hline \hline \end{tabular}
\end{table}
Table 13: State durations in the RxData time slot with a total length of 15 ms and \(s\) being the packet size in bytes.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**State** & \multicolumn{2}{c}{**Duration (\(\mu\)s)**} \\ \hline  & **CC2538** & **CC1200** \\ \hline TxDataOffsetStart & 105 & 105 \\ TxDataOffset & 1515 & 1454 \\ TxDataPrepare & \(60+(s\times 0.875)\) & \(738+(s\times 8.152)\) \\ TxDataReady & 1954 \(-(s\times 0.875)\) & \(1276-(s\times 8.152)\) \\ TxDataDelayStart & 17 & 58 \\ TxDataDelay & 349 & 369 \\ TxDataStart & 16 & 16 \\ TxData & \((3+s)\times 32-16\) & \((3+s)\times 32-16\) \\ RxAckOffsetStart & 32 & 75 \\ RxAckOffset & 3769 & 3116 \\ RxAckPrepare & 38 & 587 \\ RxAckReady & 267 & 328 \\ RxAckListenStart & 17 & 58 \\ RxAckListen & 983 & 942 \\ TxProc & 44 & 137 \\ Sleep & \(5754-(s\times 32)\) & \(5661-(s\times 32)\) \\ \hline \hline \end{tabular}
\end{table}
Table 14: State durations in the TxDataRxNoAck time slot with a total length of 15 ms and \(s\) being the packet size in bytes.  
The CC2538 radio has an identical consumption of 13.97 mA when the radio is in Sleep or Idle state because the OpenMote-CC2538 consists of both the CPU and radio, and the radio itself does not have a separate Idle or Sleep state. Instead, it has a single Off state for which the consumption was used for both the Sleep and Idle states. Thus, the CC2538 radio has only four states: TX, RX, Listen and Off.  
As expected, the difference in the consumption between an active or a sleeping CPU is nearly identical for all radio states: the CPU in active mode consumes on average 3.92 mA more than when being in sleep mode, with a standard deviation of only 0.07 mA.  
When switching the CPU of the CC2538 chip to the deeper sleep mode PM2 instead of PM_NOACTION ([[http://www.ti.com/product/CC2538/datasheet/](http://www.ti.com/product/CC2538/datasheet/)]([http://www.ti.com/product/CC2538/datasheet/](http://www.ti.com/product/CC2538/datasheet/))), while the radio was in the Sleep and Idle state (which are actually both the Off state in the CC2538 radio), the consumption dropped to 1.56 mA.