Performance enhancement of blind adaptive equalizers using environmental knowledge

2014

ACM Trans. Sen. Netw.

Most communication and localization algorithms in underwater environments have been constrained by dependencies on the Line Of Sight (LOS), which is hard to guarantee due to the inherent node mobility. This constraint hinders node discovery and ad hoc formation in underwater networks and limits the performance of routing protocols. This article introduces a novel Surface-Based Reflection (SBR) model that uses a homomorphic deconvolution technique to establish water-surface-reflected communication links. We then propose a Surface-Based Reflection Anchor-free Localization (SBR-AL) algorithm that can be employed by the individual nodes to establish a relative coordinate system. Our approach also employs a switchbeamed directional antenna model that allows each node to use the LOS estimated from SBR-AL to enable directional communication which is beneficial for higher Signal-to-Noise Ratios (SNR). The relative locations can facilitate the various network operation functions such as geo-routing and collision-free medium access. The simulation results confirm the effectiveness of the proposed approach. ACM Reference Format:Lloyd Emokpae and Mohamed Younis. 2014. Surface-reflection-based communication and localization in underwater sensor networks.

Section: Underwater Channel Multipath Effectsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Surface-Reflection-Based Communication and Localization in Underwater Sensor Networks

2014

ACM Trans. Sen. Netw.

“…Florian Schulz [5] went on to describe the length of each eigenray which is reflected at the surface first before being reflected i times during the entire propagation as:…”

Section: Figure 3: Illustrating the Four Eigenray Typesmentioning

confidence: 99%

“…Generally, in an environment where the location of the source and the destination might be unknown it is not possible for the receiver to discover the location of the transmitter due to the multipath effect of the channel. Such type of communication will require that the transmitter spread the signal using an omnidirectional scheme to properly communicate with the receiver [5], which would require a high transmission power. On the other hand, establishing a relative topology using localization techniques, e.g., the received-signal-strength (RSS), the time-of-arrival (TOA) or the angle-of-arrival (AOA), requires the consideration of measurements made by nodes in the vicinity, which would not be possible given the lack of communication links among neighbors.…”

mentioning

confidence: 99%

Surface Based Underwater Communications

2010 IEEE Global Telecommunications Conference GLOBECOM 2010

2010

In an underwater environment signal propagation for the acoustic channel is subject to major multipath effect. Therefore, most underwater communication schemes require that the position of the transmitter or receiver is fixed while using directional antennas in order to ensure high signal-tonoise ratio. However, such a requirement hinders node discovery and ad-hoc formation of underwater networks and restraints communication between autonomous underwater vehicles (AUVs) where node locations change over time. This paper proposes a novel approach to underwater communications by relying on the water surface to establish communication links. The proposed surface-based reflection (SBR) model works by requiring the transmitting node to direct its energy towards the water surface. The receiver then applies homomorphic deconvolution techniques to determine the channels impulse response used in obtaining the reflected signal. The receiver is then able to determine the location of the transmitter by triangulating the transmitted and reflected signals with respect to the water surface. Simulation experiments are provided to validate the SBR approach.

“…In shallow water, transmitted acoustic waves will take multiple paths by reflecting from the surface and the bottom before arriving at the receiver. To mitigate the multipath effect, directional transmission techniques have been adapted for underwater communications [1][4] [5].…”

Section: Introductionmentioning

confidence: 99%

Surface Based Anchor-Free Localization Algorithm for Underwater Sensor Networks

2011 IEEE International Conference on Communications (ICC)

2011

Localization in underwater environments has been constrained by the dependencies on the line of sight (LOS) due to the challenging variability's of the environment. This dependency hinders node discovery and ad-hoc formation in underwater networks and limits the performance of routing protocols. Most proposed algorithms in the literature rely on anchor nodes that are at fixed positions to serve as reference points, which is not practical in many applications. This paper introduces a novel approach to the localization problem that allows for node discovery without depending on the LOS and any fixed reference nodes. In the proposed surface-based reflection anchor-free localization (SBRAL) algorithm all nodes will apply homomorphic deconvolution to establish a water-surfacereflected communication link. SBRAL then creates a relative coordinate system where every node in the network identifies others nodes by increasing the SBRAL transmit angle and using the reflection points on the water surface as temporary reference points. The simulation results confirm the effectiveness of the proposed SBRAL algorithm.