medium Access Control l ayer for Underwater Sensor Networks ...... yANPiNg Z h ANg , yANg X i Ao , m iN Ch EN, PRAVEER BAh Ri,

Contents 9.1 Introduction ............................................................................................ 226 9.2. UASN Communication Architecture ...................................................... 228

9.2.1 Two Types of Architecture ........................................................... 228 9.2.1.1 Two-Dimensional UASNs ............................................. 228 9.2.1.2 ree-Dimensional UASNs ........................................... 228

9.2.2 Underwater Network Operating Regime ......................................229 9.2.2.1 Physical Channel ............................................................229 9.2.2.2 Technological Limitations ..............................................230