CSMA/CA-based electrocommunication system design for underwater robot groups

Abstract

Underwater communication is particularly challenging for small submarine robots that have limited power and size constraints. Inspired by weakly electric fish, a novel electric current communication (termed electrocommunication) system has been developed for small underwater robots in our previous studies. However, collision problems sometimes occur during multiple robots communication because the electrocommunication network shares a common channel. In this paper, a new CSMA/CA-based electrocommunication system is presented to solve this collision problem. An efficient circuit for communication channel state (busy or idle) detection is proposed. After that, a compact Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) algorithm is introduced and finally implemented on the system to judiciously avoid collision during multiple robot communication. The effectiveness of the proposed CSMA/CA-based communication system for underwater robot groups is well verified by both simulations and experiments with three robotic fish models.