On the fundamental limit to the use of cognitive radio in underwater acoustic sensor networks

Abstract

Cognitive communication is an effective solution to the spectrum scarcity issues in wireless networks. The underwater sensor networks are prone to large propagation delays which result in the fundamental limitation on introducing cognitive aspects in underwater scenario. This letter explores the fundamental limitation of using cognitive communication in large propagation delay underwater networks. This work proposes a method to find the optimal position of the secondary user, to minimize the interference to primary users, in an underwater cognitive acoustic network. The proposed method also considers the effect of channel randomness which is modeled using the log-normal shadowing model. The method can also be used to select and schedule the secondary user transmissions, from a set of secondary users, such that the interruption time to the primary users is minimized.

Graph‐based optimal asynchronous scheduling in large propagation delay underwater acoustic sensor networks

“…The classic problem of scheduling in wireless networks is well‐examined in the past years; however, these scheduling algorithms are confined to applications in terrestrial networks with negligible propagation delays. The networks that find applications in underwater and space are prone to high propagation delays during the transmission . In underwater acoustic sensor networks, latency during the propagation arises due to the low velocity of sound in water (1,500 m/sec), and in space communication using satellites, the substantial propagation delay occurs as a result of large distances between the transmitting and receiving nodes.…”

“…The networks that find applications in underwater and space are prone to high propagation delays during the transmission. [4][5][6] In underwater acoustic sensor networks, 7 latency during the propagation arises due to the low velocity of sound in water (1,500 m/sec), and in space communication using satellites, 8 the substantial propagation delay occurs as a result of large distances between the transmitting and receiving nodes. An efficient scheduling method reduces the time wasted during the packet transmission thereby increasing the channel utilization and network throughput.…”