An exemplary embodiment of a system for updating electronic shelf labels (ESLs) comprises multiple ESLs, and a gateway connected to the multiple ESLs to update data of the multiple ESLs. Each ESL comprises a transceiver having a media condition detector to detect whether other ESL(s) perform an update at the time slot, a controller, a memory, and a random number generator randomly selecting one of multiple time slots of a frame when an ESL update procedure begins, wherein the time slot corresponds to an index stored in the memory by the controller. The ESL performs the update at this time slot when none of said other ESL(s) performs the update at the time slot. When said other ESL(s) performs the update at the time slot, the controller enables the random number generator to randomly select another time slot from a next time frame.