Off-street “Smart Parking” Implementation
We have deployed the system in one level of a garage at Boston University, which contains 27 parking spots.
We have installed an ultrasonic sensor for each spot to detect its parking status. The ultrasonic sensor motes
together with the light indicator are attached on the ceiling above each parking space. The ultrasonic beam faces
down to the center of the spot so that a car can be detected if it parks there.
The 27 sensors form an XMesh wireless network. A gateway receives data from each sensor in the network
and forwards it to an upper level database, which serves as the PRMC. The real-time parking information is
published and updated on the web, and can therefore be obtained by users. Thus our system can still provide
service as a normal PGI system. We have built a smartphone application, which drivers can use to send parking
requests and make reservations. The application sends all user requests to a server, which operates as both DRPC
and SPAC. The server maintains driver requests, solves the optimal allocation problem (P), updates the parking
status database, and sends commands to control the parking light indicators. Fig. 5 shows the smartphone
application and real-time parking information in the website.