# A Multi-Technology Communication Platform for Urban Mobile Sensing
## 5 Results
### Use Case Description  
Ria de Aveiro (the Aveiro lagoon) is an ex-libris of this city. With a large population of inhabitants in the watershed area, it has a considerable regional and national economic importance, namely through the activities related to: port facilities, industries, aquaculture, salt-production, fishing, tourism, recreational activities, and agriculture. Regarding tourism, the miliceiro tours that go through the lagoon channels within the city heart are appealing touristic activities for those who travel to Aveiro.  
As the starting point of our platform deployment over the city of Aveiro, two fixed LoRa gateways were strategically placed over two separated locations with a high view over a broad city area, with the objective of achieving good city coverage through this communication technology. Figure 7 shows this deployment.  
With the LoRa communication assured by the gateways already installed, we took advantage of the developed DCUs and the mobile nodes software architecture to endow three miliceiros with sensory data acquisition and multi-technology communication capabilities, as shown in Figure 8. The collected data holds information about the node's geographical location and the sensory measurements from its own sensors. In order to further evaluate our multi-technology platform, we installed one RSU/WiFi gateway in a dock where some miliceiros wait for the arrival of tourists to start their cruises. The use case's overall deployment and network topology are depicted in Figure 9.  
The use case evaluation comprehends three consecutive days of February 2018. For each day, a distinct forwarding strategy over the delay-tolerant network that our platform considers was evaluated, namely Epidemic, Contacts-Based Controlled Replication with Neighborhood Classification, and Mobility-Based Controlled Replication with Neighborhood Classification. It is important to keep in mind that the routes and the number of trips made by each moleceiro are not guaranteed to be the same over the different evaluation days, as these factors depend on the availability of each moleceiro's captain and the number of tourists.  
Figure 8: DCU deployment (as mobile nodes) (**a**) A mobile DCU deployed in a moliceiro; (**b**) Closer look of a mobile DCU.  
Figure 7: LoRa gateway deployment (**a**) LoRa gateway deployed in the University of Aveiro; (**b**) LoRa gateway deployed in Aveiro’s Cultural and Congress Center.  
We present an evaluation scenario to test our multi-technology opportunistic smart city platform using a real deployment and a real application over moliceiros cruising the city of Aveiro. Some considerations and general characteristics regarding the experiments are as follows:  
* The network is composed of three moliceiros, one WiFi gateway, and two LoRa gateways.
* The positions of the gateways are fixed as shown in Figure 9.
* The LoRa communication interface is used to transmit information about the node's geographical location only. The packet's transmission rate follows the imposed regulatory duty-cycle constraints (1% duty-cycle, i.e., 36 seconds per hour).
* Each moliceiro generates data from the measurements of its own sensors with an acquisition period of six seconds;
* The WiFi communication interface is managed by the already described opportunistic delay-tolerant network (mOVE). The mOVE storage will be populated with the sensed data packets.
* The evaluation lasted three consecutive days, in which Epidemic, Contacts-Based Controlled Replication with Neighborhood Classification, and Mobility-Based Controlled Replication with Neighborhood Classification were evaluated, respectively.
* Each strategy was evaluated during a day of experiment with total duration of seven hours (10 a.m. to 5 p.m.).  
Figure 9: Use case scenario topology.