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• Models of time and energy losses for LWSN with inhomogeneous sections are calculated. • Algorithms for calculating heterogeneous LWSN with minimal end-to-end delay. • Algorithms for balancing energy consumption in a heterogeneous LWSN. • A scheme for selecting criteria and a number of nodes for deploying a heterogeneous LWSN. Linear Wireless Sensor Networks (LWSN) are typically used for monitoring infrastructure systems extending over several kilometers, where propagation conditions can be inhomogeneous in different sections of the network. Obstacles and reflecting objects contribute to bit errors in data packets, which take extra time and energy to recover. However, the impact of the inhomogeneities across LWSN sections on the time and energy performance of the entire network remains underreported. In addition, conventional methods of building LWSN by distributing relay nodes among inhomogeneous sections have failed to balance operability and energy efficiency criteria. This article examines the models of time and energy loss in LWSN sections showing different signal fading, represented by the Rician K-factor in the expressions for the bit error probability. On the basis of the dependences of time losses on inter-node distances, algorithms for deploying a heterogeneous LWSN are proposed according to the criterion of minimizing end-to-end network delay without restrictions on hardware and energy resources or when distributing a limited number of nodes. As an alternative to the efficiency criterion, we propose algorithms for balancing power consumption in a heterogeneous LWSN at an acceptable level of power loss without limiting the number of nodes or at the lowest level of power loss with a limit on the number of nodes. Experiments were carried out on CC2500 TI node transceivers in five inhomogeneous LWSN sections, where K-factor ranges from 5 to 100, in order to demonstrate the efficiency of the proposed algorithms. Results showed that the end-to-end delay and energy loss can be reduced by 1.36 and 2.4 times, respectively, compared to those in networks with uniformly distributed nodes. To further assess the operability and energy efficiency of the algorithms, a scheme is proposed based on the ratio of normalized concessions in the Pareto region. Additionally, the optimal number of nodes is determined when selecting a rational algorithm for deploying a heterogeneous LWSN. [ABSTRACT FROM AUTHOR]

The versatility of simple electronic nodes and debugging of communication protocols in unlicensed frequency bands constitute the main reasons for the adoption of industrial wireless sensor networks (IWSNs). However, the industrial environments, in which IWSNs function, are characterized by a harsh impact of physical and electromagnetic factors that destabilize the operation of equipment and worsen the noise immunity of channels. To consider the effect of these two groups of factors on communication quality, we develop a novel model of an IWSN channel as the dependence of bit error probability (BEP) on signal distortions and interference impact. We found that direct sequence spread spectrum (DSSS) codes of a signal have different effects on the compensation of nonlinear signal distortions and external interference. Further, we propose an algorithm for the distribution of DSSS codes among real transmitters by BEP values in channels with known additive and multiplicative interference. Here, the distribution of codes is based on the minimax criterion. Finally, for cases when a signal is characterized by a-priori uncertainties of fading, we suggest an alternative algorithm for selecting a DSSS code based on Pareto bicriteria optimization. [Display omitted] • We model an IWSN channel with hardware signal distortion, fading and narrowband interference. • An algorithm for distributing DSSS codes among real transmitters minimizes BEP in the worst channel. • An algorithm for DSSS code selection with signal fading uncertainty reduces required computational costs. [ABSTRACT FROM AUTHOR]

[Display omitted] • We model wireless channels in terms of the hardware distortion of BFSK signals. • A complex indicator for the hardware distortion of signals is justified. • The table of energy consumption for nodes with various radio modules is calculated. • We propose a criterion for energy-efficient distribution of radio modules among nodes. Wireless sensor networks (WSNs) are widely used in various practical applications due to the availability of sensor and relay nodes. The imperfect technical condition of the modem part in nodes causes the hardware distortion of signals and the loss of messages in communication channels. Lost data recovery requires additional energy consumption, contributing to the premature discharge of batteries in individual nodes and decreased network lifetime. In this study, we propose an algorithm for the optimal energy-efficient distribution of radio modules (RMs) among the established node positions in terms of the technical condition of equipment using a minimax criterion. We developed physical layer models for the channels exhibiting incoherent reception of a priori distorted BFSK (binary frequency shift keying) signals under noise and Rayleigh and Rice fading conditions. Hardware distortions in these models are considered as a complex indicator represented by a coefficient showing similarity between the signal at the actual RM output and a reference signal with nominal parameters. The energy of the network is balanced due to the optimal distribution of the RMs among the node positions, taking into account the energy consumption of various WSN nodes. [ABSTRACT FROM AUTHOR]