Several routing schemes in ad hoc networks first establish a virtual backbone and then route messages via back-bone nodes. One common way of constructing such a backbone is based on the construction of a minimum connected dominating set (CDS). In this paper we present a very simple distributed algorithm for computing a small CDS. Our algorithm has an approximation factor of at most 6.91, improving upon the previous best known approximation factor of 8 due to Wan et al. [INFOCOM'02], The improvement relies on a refined analysis of the relationship between the size of a maximal independent set and a minimum CDS in a unit disk graph. This subresult also implies improved approximation factors for many existing algorithm.

A Simple Improved Distributed Algorithm for Minimum CDS in Unit Disk Graphs

Wireless Sensor Networks (WSN) is in large use in today’s world against the challenges encountered in the Sensor world. Energy consumption, routing, interference mitigation are a matter of concern in WSN. Perhaps, overruling interference mitigation would solve a number of interconnected problems in WSN. The proposed work is narrowed down to minimize interference in distributed homogenous WSN, ensuring that all the nodes in the network operate with the same transmission power. In this paper, an optimal shortest distance algorithm, Dynamic-Optimal Shortest Path Algorithm (DOSPA) is proposed to identify the shortest path in communication between point to point nodes. As the data traverses a number of intermediary nodes, a privileged network topology has to be built to ensure proper transmission of data. An ideal network topology is hence built dynamically for data transmission. However, a collision between data packets in interconnecting nodes is likely to occur. Furthermore, to minimize collision a non-persistent round-robin CSMA/CD algorithm is proposed. We study the network throughput, packet delay, corruption ratio by increasing the number of nodes and hence also analyzing the system in saturation state. It’s found that Packet Corruption Ratio (PCR) with CSMA+DOSPA is minimized compared to CSMA. Thus, interference reduction in distributed homogenous nodes is substantially minimized.

Interference mitigation and optimal hop distance measurement in distributed homogenous nodes over wireless sensor network

Continued advancements in microprocessors, electronics, and communication technology have led to the design and development of sensing devices with increased functionalities, smaller sizes, larger processing, storage, and communication capabilities, and decreased cost. A large number of these sensor nodes are used in many environmental, infrastructure, commercial, and military monitoring applications. Due to the linearity of a good number of the monitored structures such as oil, gas, and water pipelines, borders, rivers, and roads, the wireless sensor networks (WSNs) that are used to monitor them have a linear topology. This type of WSN is called a linear sensor network (LSN). In this paper, two distributed algorithms for topology discovery in thick LSNs are presented: the linear backbone discovery algorithm (LBD) and the linear backbone discovery algorithm with x backbone paths (LBDx). Both of them try to construct a linear backbone for efficient routing in LSNs. However, the LBD algorithm has the objective of minimizing the number of messages used during the backbone discovery process. On the other hand, the LBDx algorithm focuses on reducing the number of hops of the data messages transmitted from the nodes to the sink. LBD and LBDx exhibit good properties and efficient performance, which are confirmed by extensive simulations.

https://www.mdpi.com/2224-2708/10/3/49/pdf

Distributed Algorithms for Multiple Path Backbone Discovery in Thick Linear Sensor Networks

The article presents a power efficient algorithm for backbone based routing in wireless networks. In most of the backbone formation algorithms, the members of the backbone always remain active. Consequently, their power dissipates faster due to additional routing related responsibilities. Therefore, the members of backbone are prone to failure and the life of backbone is reduced. However, in our algorithm the members of backbone do not remain continuously on and due to reduced power consumption the life of backbone is longer. The working of the protocol is illustrated through a suitable example. We also present the correctness proof of the algorithm The simulation analysis is postponed for full journal paper.

Power efficient routing using dominator alteration in wireless networks

A Connected Dominating Set (CDS) of a graph representing a Wireless Sensor Network can be used as a virtual backbone for routing through the network. Since the sensors in the network are constrained by limited battery life, we desire a minimal CDS for the network, a known NP-hard problem. In this paper we present three randomized algorithms for constructing a CDS. We evaluate our algorithms using simulations and compare them to the two-hop K2 algorithm and two other greedy algorithms from the literature. After pruning, the randomized algorithms construct a CDS that are generally equivalent in size to those constructed by K2 while being asymptotically better in time and message complexity. This shows the potential of significant energy savings in using a randomized approach as a result of the reduced complexity.

/pdf/randomized-algorithms-for-approximating-a-connected-3dhye2btnn.pdf

Randomized algorithms for approximating a Connected Dominating Set in Wireless Sensor Networks

This paper reports the analysis, design, and experimental characterization of a piezoelectric intracochlear hydrophone and amplifier system to function as an implantable microphone for totally-implantable cochlear implants. We derived an analytical model for the piezoelectric hydrophone, which we validated with finite-element modeling (FEM) and experiments. We developed a circuit and noise model of the amplifier, which we verified through measurements. We proposed a PVDF-TrFE intracochlear hydrophone with a charge amplifier co-designed for maximum performance: sensitivity, bandwidth, and output noise. To characterize the hydrophone and amplifier, we used a vibrating water column calibration method. We determined the shielding and experimental design considerations necessary to collect reliable data. The system presented here achieved an overall sensitivity of 20.6 mV/Pa at 3 kHz, a bandwidth of 470 Hz to 16 kHz, and a root-mean-square (RMS) output noise of 17.6 mV dominated by the amplifier. Our approach for an implantable microphone proves to be a promising candidate for cochlear implants.

Aaron Yeiser

Papers

Randomized algorithms for approximating a Connected Dominating Set in Wireless Sensor Networks

A Pvdf-Trfe Intracochlear Hydrophone and Amplifier For Totally Implantable Cochlear Implants