# Internet of Bikes: A DTN Protocol with Data Aggregation for Urban Data Collection
## 7 Performance Evaluation of IoB-DTN and IoB Long-Range  
In this section, we are interested in comparing the performance of IoB-DTN protocol and a low-power long-range technology. IoB-DTN protocol is a multi-hop protocol since there are bike-to-bike and bike-to-bike station communications. In a long range technology, only bike-to-bike station communication is allowed, as shown in Figure 18. For that, we consider IoB-DTN protocol with a radio propagation that provides us \(\sim\)1 km as communication range, it is denoted IoB-Long Range (IoB-LR). By following IoB-LR, each node generates periodically data packets and stores them in its buffer. When the duty cycle is over and when the node lies in the area of a base station, it sends all data stored in its buffer. Here, we assume that IoB-LR represents a low-power long-range technology, LoRa type. More precisely, we suppose that IoB-LR follows the model of LoRa Semtech SX1272 chipset [48]. As for IoB-DTN protocol, we consider, for our theoretical results, the parameters offered by the Qualcomm AR6004 802.11p chipset [49]. The parameters used for both considered models are depicted in Table 3.  
It is important to notice that the packet duration for the long range, LoRa type, varies according to the four considered cases. As an example, considering the SB-SDC scenario: 250 as buffer size and 50 s as duty cycle, the 250 packets stored in the buffer have to be sent during the 50 s time frame of the duty cycle. Therefore, each packet needs to have a maximum airtime of 0.2 s. It is also interesting to point out that the packet size varies for each case for IoB-LR. To better understand this, we refer the reader to Figure 19 which shows the airtime in seconds (time to forward a packet) for different spreading factors SF (length of the code sent) and payload size given by an operational LoRaWAN, namely The Things Network [50]. In this work, the bandwidth used is 125 K  
Figure 18: Illustration of IoB Long-Range. (forward error correction) is \(\frac{4}{5}\). The data in Figure 19 are used to determine the packet size for each case for IoB-LR. The values of the payload sizes obtained for different spreading factors for each case are presented in Table 4.  
As mentioned above, the spreading factor represents the number of chirps used to encode a bit and it varies from _SF7_ to _SF12_. The higher is the chirp rate, the better is the reconstitution of the received signal, while it has a significant delay to forward a bit. We consider payload sizes with the spreading factor SF7 for IoB-LR in all our scenarios since it provides the highest values. \begin{table}
\begin{tabular}{l c c c c c c c} \hline \hline  & **Airtime (s)** & \begin{tabular}{c} **PS (Byte)** \\ **SF 7** \\ \end{tabular} & \begin{tabular}{c} **PS (Byte)** \\ **SF 8** \\ \end{tabular} & \begin{tabular}{c} **PS (Byte)** \\ **SF 9** \\ \end{tabular} & \begin{tabular}{c} **PS (Byte)** \\ **SF 10** \\ \end{tabular} & \
\begin{tabular}{c} **PS (Byte)** \\ **SF 11** \\ \end{tabular} &
\begin{tabular}{c} **PS (Byte)** \\ **SF 12** \\ \end{tabular} \\ \hline
**250–50** & 0.2 & 92 & 40 & - & - & - & - \\
**250–150** & 0.6 & 260 & 220 & 100 & 28 & - & - \\
**500–50** & 0.1 & 20 & - & - & - & - & - \\
**500–150** & 0.3 & 175 & 80 & 25 & - & - & - \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Payload sizes (PS) of IoB-LR with different SF. Figure 19: Airtime for different SF and payloads [50]. \begin{table}
\begin{tabular}{l l l} \hline \hline  & **IoB** & **IoB-LR** \\ \hline
**Model** & \multicolumn{1}{l}{Datasheet Qualcomm AR6004} & Semtech SX1272 \\ \hline
**Tx** & 237 mA & 26 mA \\ \hline
**Rx** & 66 mA & 12 mA \\ \hline
**Packet duration** & 213 \(\upmu\)s &
\begin{tabular}{l} 250–50: 0.2 s \\ 250–150: 0.6 s \\ 500–50: 0.1 s \\ 500–150: 0.3 s \\ \end{tabular} \\ \hline
**ACK duration** & 213 \(\upmu\)s &
\begin{tabular}{l} 0.05 s \\ 250–50: 92 Byte \\ 50–150: 260 Byte \\ 500–50: 20 Byte \\ 500–150: 175 Byte \\ \end{tabular} \\ \hline \hline \end{tabular}
\end{table}