Stopping Criteria for Distributed Data Storage in Compressive CrowdSensing Systems

Distributed data storage (DDS) in mobile crowdsensing (MCS) systems has recently gained popularity. Data should be briefly saved on participants’ mobile devices before being gathered once the centralized cloud servers resume normal operations. For MCS systems, the existing DDS strategies briefly considered reconstructing the scene as precisely as possible without thinking about the costs of each step. However, our goal is to obtain a sufficiently accurate approximation of the sensing data from mobile participants with as few costs as possible. We note a crucial observation: when a specified number of participants have been transmitted to a central server, the sensing data has already been well reconstructed, and the accuracy advancement with additional transmitted participants is minimal. In our scheme, two stopping criteria are proposed for DDS in compressive MCS, which aims to enhance recovery performance while reducing the costs of the whole process. In the first stopping criterion, we established a rule to stop the continued recruitment of participants. The algorithm adaptively increases the number of participants until the reconstruction accuracy meets the requirement. Another stopping criterion of the reconstruction algorithm is designed to find a more accurate number of iterations than the original. The experiment results demonstrate that the first stopping criterion can reduce participants’ collection while obtaining an approximate value. The second stopping criterion assists the reconstruction algorithm in terminating at a more appropriate number of iterations, saving computing costs while ensuring accuracy.