Date of Completion


Embargo Period



Underwater acoustic network, media access control, cognitive communication, cooperative communication, coordinated communication

Major Advisor

Jun-Hong Cui

Associate Advisor

Mohammad Khan

Associate Advisor

Song Han

Associate Advisor

Zheng Peng

Field of Study

Computer Science and Engineering


Doctor of Philosophy

Open Access

Open Access


Underwater acoustic networks (UANs) have a wide range of applications. However, UANs face grand challenges on the narrow communication bandwidth. To tackle this issue, in this dissertation, I explore three critical techniques: cooperative communications (COP-COM), cognitive communications (COG-COM) and coordinated communications (COD-COM), to improve acoustic spectrum usage.

In the first research thread, I propose a new relay selection criterion, called cooperative best relay assessment (COBRA), for underwater COP-COM. COBRA takes into account not only the spectral efficiency but also the long propagation delays of acoustic signals. In addition to COBRA, I develop a new cooperative scheme, called mirror node assisted communication (MNAC). MNAC harnesses the destructive interference of acoustic waves, and makes multiple data streams sent in parallel without causing any collisions.

In the second research thread, I propose a receiver-initiated spectrum management (RISM) system for underwater COG-COM. Control packets in RISM are shared amongst spectrum sensing, collision avoidance and spectrum decision. In addition to RISM system, I design a dynamic control channel MAC (DCC-MAC), to mitigate congestion on control channel. In DCC-MAC, nodes could flexibly extend or return the bandwidth of control channel based on the situation of network traffic.

In the third research thread, I propose a competitive transmission media access control (MAC), called CT-MAC, for COD-COM. CT-MAC aims to coordinate the channel sharing among users. In this protocol, control packets produced by each user only need to reach the immediate neighbors with a low transmission power.