Step  1. The ROI is divided into subrectangles which satisfy . The communication range of the mobile
anchor is equal to the resolution, that is, .
Step  2. The mobile anchor traverses the ROI following the regular hexagon movement trajectory (the concretely movement
trajectory is depicted in Figures 5 and 7) while periodically broadcasting anchor packets , where
denotes the sending time, stands for its current location, and represents the packet ;
Step  3. Unknown nodes receive the anchor packets broadcasted by the mobile anchor and estimate distances to them
by using the RSSI technique;
Step  4. Each unknown node decides if any of the three noncoplanar anchor coordinates can almost form a regular
triangle and if it is within the regular triangle. If so, the unknown node calculates its location by using the trilateration.
Algorithm 1: MAALRH algorithm.