Position adjustment-based location error-resilient geo-opportunistic routing for void hole avoidance in underwater sensor networks: Geo-opportunistic routing for void hole avoidance in underwater WSNs

This paper presents four routing protocols for Underwater Sensor Networks (USNs): Location Error-resilient Transmission Range adjustment-based protocol (LETR), Mobile Sink-based GEographic and Opportunistic Routing (MSGER), Mobile Sink-based LETR (MSLETR), and Modified MSLETR (MMS-LETR). LETR considers transmission range levels for finding neighbor nodes. If a node fails to find any neighbor node within its defined maximum transmission range level, it recovers from communication void regions using depth adjustment technology. MSGER and MSLETR avoid depth and transmission range adjustment and overcome the problem of communication void regions using MSs, whereas MMS-LETR takes into account noise attenuation at various depth levels, elimination of retransmissions using multi-path communication and load balancing. The performance of our proposed protocols is evaluated through simulations using different parameters. The simulation results show that MSS-LETR supersedes all counterpart schemes in terms of packet loss ratio. LETR significantly improves network performance in terms of energy consumption, packet loss ratio, fraction of void nodes, and the total amount of depth adjustment.