دانلود رایگان مقاله حداکثر توان عملیاتی در شبکه بی سیم مولتی هاپ تحت محدودیت سری

Abstract

This paper analyzes the achievable throughput of multi-hop sensor networks for industrial applications under a secrecy constraint and malicious jamming. The evaluation scenario comprises sensors that measure some relevant information of the plant that is first processed by an aggregator node and then sent to the control unit. To reach the control unit, a message may travel through relay nodes, which form a multi-hop wireless link. At every hop, eavesdropper nodes attempt to acquire the messages transmitted through the legitimate link. The communication design problem posed here is how to maximize the multi-hop throughput from the aggregator to the control unit by finding the best combination of relay positions (i.e. hop length: short or long) and coding rates (i.e. high or low spectral efficiency) so that the secrecy constraint is satisfied. Using a stochastic-geometry formulation, we show that the optimal choice of coding rate is normally high and depends on the path-loss exponent only, while a greater number of shorter hops are preferable to smaller number of longer hops in any situation. For the investigated scenarios, we prove that the optimal throughput subject to the secrecy constraint achieves the unconstrained optimal performance – if a feasible solution exists.

6. Conclusions and final remarks

This paper analyzes the throughput of industrial multi-hop machine-to-machine networks under a secrecy constraint subject to malicious jamming. The scenario under analysis consists in an aggregator node, which collects and processes the sensor measurements, and a control unit that needs the proceeded information. This communication is wireless and may occur over multiple hops, and the communication engineer is expected to find the optimal position of the relay nodes and the coding rates used in the singlehop links so as to maximize the throughput in [bits/s/Hz] while respecting a given secrecy constraint and accounting for malicious jamming. By employing our stochastic-geometric-based model to characterize the uncertainties involved in the eavesdroppers’ and jammers’ positions, we first showed that the optimal choice without any secrecy constraint of coding rate (spectral efficiency) depends only on the path-loss exponent and normally assumes a high value. To sustain such a high rate, a great number of shorter hops are then preferable to a small number of longer hops. When the secrecy constraint is assumed, we proceeded with the throughput optimization and proved that the unconstrained performance can be achieved with the same optimal relay positions and coding rates only if a feasible solution exists. Otherwise, there is no solution for the problem that satisfies the minimum level of secrecy required. As a next step, we expect to evaluate our guidelines in actual industrial environments by following the insights provided herein. To do so, we aim at designing a feasible experimental deployment that utilizes established standards for industrial wireless systems. It is also important to point out that, although this analysis has been presented focusing on industrial deployments, our framework can be also extended to different kind of smart applications such as homes, cities, energy grids or highways.