Research On The Data Link Layer Mechanism Over Narrowband Power Line Communication System

Power line communication refers to the communication mode which uses power line as the transmission medium.As domesitc broadband power line communication technology is immature at present,it is very important to research on high-speed narrowband power line communication technologysince power line communication technology has a broad developing prospect under the advantage of pervasive power distribution.G3-PLC standard and PRIME standard which are the most mature and stable standards in narrowband power line communication industry have been widely used abroad today.However,G3-PLC standard and PRIME standard do not support the zero-transmission mode.As a result,they are not able to adapt to the domestic complex power grid environment leading to low reliability and netwoking efficiency in the domestic application.Therefore,it is necessary to study the main mechanisms of the data link layer over narrowband power line communication considering the domestic special power line environment and the actual demands.The main goal of this paper is to design data link layer mechanisms over narrowband power line communication that can support the zero-transmission mode designated for domestic application environment,and to research on the performance of these mechanisms.In the paper,we focus on channel access mechanism and the transmission mechanism of the data link layer.In more detail,firstly,the network topology and protocol stack structure of the narrowband power line carrier communication protocol is introduced.The channel access mechanism and the data transmission mechanism of the data link layer are analyzed as well.Secondly,the basic implementation mechanism and main function module of the data link layer simulation platform are illustrated based on which the data link layer mechanism simulation system of narrowband power line carrier communication.Also,the realization process of the channel access mechanism,the data transmission mechanism and the data encapsulation processing mechanism of the data link layer are designed to be implemented on the simulation platform.Next,an CSMA/CA mechanism based on the binary exponential backoff algorithm is used to support the zero-transmission mode,and evaluated on the simulation platform in different narrowband power line carrier communication scenarios in terms of delay,network throughput and the transmission success rate.Then,according to the disadvantage of the existing CSMA/CA mechanism based on binary exponential backoff algorithm,we design a short backoff slot CSMA/CA mechanism and analyze its performancevia simulations.In addition,we also study the mechanism of RTS/CTS in narrowband power line carrier communication applicability for the hidden station problem.Finally,in order to satisfy the needs for business of different priorities,a CSMA/CA mechanism which supports strict priority control is put forward,the performance of which is smulated and analyzed in terms of throughput,delay and transmission rate etc.The simulation results prove the correctness of the narrowband power line carrier communication protocol of data link layer channel access mechanism and the data transmission mechanism of the simulation system.Also the effectiveness of the proposed multiple channel access mechanisms of the data link layer is presented.Furthermore,the corresponding channel access mode can be tunable according to the actual application scenarios.