CFDAMA-SRR: A MAC Protocol for Underwater Acoustic Sensor Networks

Abstract

Underwater acoustic sensor networks are an enabling technology for many applications. Long propagation delays and limited bandwidth of the acoustic channel place constraints on the trade-off between achievable end-to-end delay, channel utilization, and fairness. This paper provides new insights into the use of the combined free/demand assignment multiple access (CFDAMA) schemes. The CFDAMA can be classified as adaptive TDMA, where capacity is usually assigned on demand. The CFDAMA with round robin requests (CFDAMA-RRs) are shown to minimize end-to-end delay and maximize channel utilization underwater. It sustains fairness between nodes with minimum overhead and adapts to changes in the underwater channel and time-varying traffic requirements. However, its performance is heavily dependent on the network size. The major contribution of this paper is a new scheme employing the round robin request strategy in a systematic manner (CFDAMA-SRR). Comprehensive event-driven Riverbed simulations of a network deployed on the sea bed show that the CFDAMA-SRR outperforms its underlying scheme, CFDAMA-RR, especially when sensor nodes are widely spread. Considering node locations, the novel scheme has a bias against long delay demand assigned slots to enhance the performance of the CFDAMA-RR. The illustrative examples show good agreement between the analytical and simulation results. INDEX TERMS CFDAMA, medium access control, TDMA, underwater acoustic sensor networks.

RPCP‐MAC: Receiver preambling with channel polling MAC protocol for underwater wireless sensor networks

“…Energy saving mechanism is the key area of this research domain. [26][27][28] The aim of most of the protocols is to achieve low energy consumption in transmitting packets between nodes and to improve system performance by avoiding collision. These protocols also have the goals of high throughput, low delay, and minimum packet loss.…”

“…In the next section, we use the derived Equations (25), (42), and (27) for performance analysis of RPCP-MAC in terms of energy consumption, throughput, and PDR, respectively.…”

An Adaptive TDMA-based MAC Protocol for Underwater Acoustic Sensor Networks

“…Following that, [6] introduces a new scheme based on CFDAMA, called CFDAMA with Intermediate Scheduler, which enhances the overall delay/utilisation performance by minimising the average round-trip time between sensor nodes and the CFDAMA central scheduler. Following that, [5] introduces a CF-DAMA scheme, namely CFDAMA with Systematic Round Robin requests (CFDAMA-SRR). It increase the eectiveness of CFDAMA underwater by systematising the distribution of request slots based on the location of nodes with respect of the network gateway.…”

“…Scheduling-based techniques are preferred over other separation techniques. They support adaptive channel capacity allocation and allow variable data rates [5] [13]. However, underwater acoustic channels feature long time-varying propagation delays, leading to temporal and spatial uncertainty [9], the phenomena of space unfairness [3] and momentary connection losses.…”

“…To this end, single-hop topologies are preferred where feasible to minimise the complexity of scheduling algorithms and increase their feasibility. Applications of UASNs are still evolving, and it is envisioned that primarily two types of data trac will characterise such sensing networks: eventdriven and periodic sensing [5] [ 8]. The two types signicantly dier in their trac patterns.…”