# Evaluation of IEEE802.15.4g for Environmental Observations
## 2 Materials and Methods
### Software  
The range test scripts are written in Python and they perform the processes depicted in Figure 2. When powering the nodes, the GPS modules at each node wait for satellite signals. Once the GPS gets a lock signal, they feed the rPis with GMT and position, enabling the experiment scripts to start. The test script then waits for the signal from the push button to start the experiment, therefore a person per node is needed. When the signal is received from the push button, the script waits for the start of the next minute. They drive the radio board through an experiment, making the TX node loop over the 31 radio settings and sending burst of 100 frames of 127 B and 100 frames of 2047 B for a total of 200 frames sent per radio setting. On the RX nodes, the script configures the radio board with the same PHY and frequency as the TX node at the same time. Since the System time at the nodes is the same (GMT, fed by the GPS module), the nodes are tightly synchronized. An experiment consists in the node sending 100 frames of 127 B and 100 frames of 2047 B, using the 31 radio settings shown in Table 6. 127 B is the maximum size of the previous version of the standard, defined in 2006, that uses O-QPSK with 250 kbps, and that can be used just as a comparison for the interested reader willing to perform the same experiments with that technology. 2047 B is the maximum size of the 'g' amendment, and now appended to the standard as SUN-PHYS. We measure the time the TX node takes to transmit 100 frames of 127 B and 100 frames of 2047 B over each one of the radio settings tested, therefore we know for how long RX nodes need to listen on every configuration. Appropriate guard times are taken into account, in order to guarantee that the RX nodes are listening when the TX node starts transmitting. With this information, we build the sequence of radio settings that the nodes need to implement and for how long. Since the nodes start executing the range test scripts aligned with the next change of minute, they are synchronized within milliseconds. \begin{table}
\begin{tabular}{l r r r r} \hline \hline
**PHY Alias** & **Max TX Power** & \begin{tabular}{c} **Current Consumption** \\ **@max TX power** \\ \end{tabular} & \begin{tabular}{c} **Receiver** \\ **Sensitivity** \\ \end{tabular} & \
\begin{tabular}{c} **Sensitivity** \\ **Condition** \\ \end{tabular} &
\begin{tabular}{c} **Link** \\ **Budget** \\ \end{tabular} \\ \hline OFDM1-800 & +10 dBm & 76 mA & \(-\)104 dBm & 118 dB \\ OFDM2-50 & +10 dBm & 76.5 mA & \(-\)111 dBm & 125 dB \\ OFDM2-100 & +10 dBm & 76.7 mA & \(-\)111 dBm & 125 dB \\ OFDM2-200 & +10 dBm & 76.7 mA & \(-\)108 dBm & 122 dB \\ OFDM2-400 & +10 dBm & 76.7 mA & \(-\)106 dBm & 120 dB \\ OFDM2-600 & +10 dBm & 76.8 mA & \(-\)104 dBm & 125 dB \\ OFDM2-800 & +10 dBm & 77.1 mA & \(-\)101 dBm & 115 dB \\ OFDM3-50 & +10 dBm & 76 mA & \(-\)113 dBm & 127 dB \\ OFDM3-100 & +10 dBm & 76.1 mA & \(-\)109 dBm & 123 dB \\ OFDM3-200 & +10 dBm & 76.1 mA & \(-\)107 dBm & 121 dB \\ OFDM3-300 & +10 dBm & 75.3 mA & \(-\)106 dBm & 120 dB \\ OFDM3-400 & +10 dBm & 75.8 mA & \(-\)102 dBm & 116 dB \\ OFDM3-600 & +10 dBm & 76 mA & \(-\)97 dBm & 111 dB \\ OFDM4-50 & +11 dBm & 75.8 mA & \(-\)111 dBm & 126 dB \\ OFDM4-100 & +11 dBm & 75.8 mA & \(-\)109 dBm & 124 dB \\ OFDM4-150 & +11 dBm & 75.8 mA & \(-\)108 dBm & 123 dB \\ OFDM4-200 & +11 dBm & 75.8 mA & \(-\)105 dBm & 120 dB \\ OFDM4-300 & +11 dBm & 75.8 mA & \(-\)101 dBm & 116 dB \\ \hline QQPSK-6.25 & +14 dBm & 84.1 mA & \(-\)123 dBm & PSDU length 20 B & 141 dB \\ QQPSK-12.5 & +14 dBm & 84.1 mA & \(-\)121 dBm & PER \textless{} 10\% & 139 dB \\ QQPSK-25 & +14 dBm & 84.1 mA & \(-\)119 dBm & 137 dB \\ QQPSK-50 & +14 dBm & 84.1 mA & \(-\)117 dBm & PSDU length 250 B & 135 dB \\  & & & PER \textless{} 10\% & \\ \hline \hline \end{tabular}
\end{table} 
Table 6: _Cont._The inter-frame spacing time is 20 ms, enough to avoid collisions between consecutive frames. Each frame has a sequence number, allowing us to know which frames were well received and which were not.