دانلود رایگان مقاله معیارهای مسیریابی MAC آگاه برای اینترنت اشیا

abstract

The development of the internet of things (IoT) has significantly affected the concept of wireless networking. As the number of wireless devices is rising, new medium access control (MAC) and routing protocols have been developed to guarantee end-to-end network performance. When existing layered solutions are stacked together, there might be detrimental effects on the overall network performance. In this paper, an analysis of MAC and routing protocols for IoT is provided with focus on the IEEE 802.15.4 MAC and the IETF RPL standards. It is shown that existing routing metrics do not account for the complex interactions between MAC and routing, and thus novel metrics are proposed. This enables a protocol selection mechanism for selecting the routing option and adapting the MAC parameters, given specific performance constraints. Extensive analytical and experimental results show that the behavior of the MAC protocol can hurt the performance of the routing protocol and vice versa, unless these two are carefully optimized together by the proposed method.

8. Conclusions

In this paper, an analysis to characterize the complex interdependence among the basic MAC and routing protocols in IoT was presented. Moreover, a mathematical framework for joint optimization of the MAC and the routing layers parameters was proposed to enhance the existing standards. Specifically, novel metrics that take into account the dynamic behavior of the MAC and routing layers were introduced: R-metric and Q-metric. An extensive comparison of the existing ETX metric with the R-metric, which considers both the level of contention and the protocol parameters, was performed. It was shown that the R-metric achieves high average link reliability. However, it is not able to provide balanced reliability in the network. The Q-metric was proposed, having in mind that a minimum reliability or a maximum delay is required for all the nodes. Extensive experiments, where the proposed metrics were compared to the existing back-pressure routing, supported our mathematical analysis. The inclusion of such an analysis and an experimental study in the current standardization process could be very beneficial in the direction of improving the performance of IoT protocols under realistic conditions.