Bi-directional Probing for Neighbor Discovery

The explosive growth of mobile sensors and smartphones in recent years has contributed to the change of communication manner. The faster and more convenient way to communicate is advocated, which leading to the increasing attention to Mobile Social Networking. Meanwhile, the popularity of location-based services makes it possible and meaningful to associate with the Proximity-based Mobile Social Networks (PMSN). People prefer to communicate with others who have same interest at anytime and anywhere with local communication capacity such as Bluetooth and WiFi. Many PMSN applications require collaborative participation of multi-users. Hence, neighbor discovery becomes an important precondition for accomplishing proximity-based social activities. Due to the limitation of battery power and communication range, it is not practical to explore neighbors nearby all the time. Based on the balance of energy-consumption and discovery latency, we propose a bi-directional probing protocol to guarantee discovery which allows nodes operating at relatively low duty-cycle. Subsequently, we employ striped-probing to reduce the worst-case and average-case discovery latency. We conduct extensive simulation experiments to examine the protocol. Our protocol is comparable with Searchlight in the worst-case, but outperforms Searchlight about 25% in average-case.