On Multi-round Sensor Deployment for Barrier Coverage

We consider the k-barrier coverage problem, that is, the problem of deploying sensors on a border or perimeter to ensure that any intruder would be detected by at least k sensors. With random deployment of sensors, there is always a chance of gaps in coverage, thereby necessitating multiple rounds of deployment. In this paper, we study multi-round wireless sensor deployment on a border modeled as a line segment. We present two different classes of deployment strategies: complete and partial. In complete strategies, in every round, sensors are deployed over the entire border segment, while in partial strategies, sensors are deployed over only some part(s) of the border. First, we analyze the probability of k-coverage for any complete strategy as a function of parameters such as length of barrier to be covered, the width of the intruder, the sensing range of sensors, as well as the density of deployed sensors. Second, we propose two specific deployment strategies - Fixed-Density Complete and Fixed-Density Partial - and analyze the expected number of deployment rounds and expected total number of deployed sensors for each strategy. Next, we present a model for cost analysis of multi-round sensor deployment and calculate, for each deployment strategy, the expected total cost as a function of problem parameters and density of sensor deployment. Finally we find the optimal density of sensors in each round that minimizes the total expected cost of deployment for each deployment strategy. We validate our analysis by extensive simulation results.