Demand Assigned Channel Allocation Applied to Full Duplex Underwater Acoustic Networking

Abstract

Abstract : Acoustic communications provide a viable means for underwater networking. However, extreme propagation delays, limited bandwidth, and half duplex communications, with its inherent use of delay inducing collision avoidance media access and flow control, severely limit the throughput and power of such networks. While full duplex communications eliminate access coordination and enable more effective flow control, they impact transmission time and may lead to wasted channel capacity. The authors hold that, by combining demand assigned multiple access techniques with bandwidth on demand allocations, the cost of full duplex, in terms of latency, can be significantly reduced. This paper makes two contributions. First, it formally evaluates the limitations imposed on delay-constrained networks by adherence to stop-and-wait methods. Second, it demonstrates by simulation the potential to reduce message latency by inverse multiplexing, using the aforementioned techniques, for delay-challenged networks incorporating full duplex communications. These levels of latency improvement, observed through simulation, provide a lower bound for performance in delay challenged networks that employ bandwidth-on-demand and sliding-window techniques under similar traffic load parameters.