Error Control Mechanisms For Nanonetworks

Nanonetworks are composed of a large number of nanoscale or microscale communication devices.Due to the size of single nanocomponent is only about a few cubic nanometers,it has new characteristics at the nanoscale,and has a very broad application prospect,such as in the biomedical field,in the environmental monitoring field,in the defense and military field as well as in the industrial and consumer goods field,etc.In recent years,with the development of new nanomaterials,i.e.,carbon nanotubes and graphene,new solutions have been provided for electromagnetic wave communication at high operating frequencies,enabling nanoantennas to effectively radiate electromagnetic waves in the Terahertz(THz)band.Therefore,THz band has been recommended as a communication band for nanodevices.In addition,owing to the size of nanonode is very small,the energy harvesting technology can make nanonode maintain its working energy consumption by capturing energy from the external environment,which also makes the energy state of nanonode is uncertain,and may cause data transmission errors.Moreover,Due to the low-power communication limitations as well as the very severe path loss and molecular absorption characteristics of THz band,it is very easy to cause transmission errors during communicarion.Hence,an error control method is urgently needed to solve the above problems and ensure the accuracy of data transmission.This paper focuses on the core issue for error control mechanism based on energy harvesting for nanonetworks.The main research work and results are summarized as follows:1.In order to improve the utilization efficiency of nanonode for capturing energy,prolong the life cycle of nanonode,and reduce data transmission errors,an error control mechanism(ECP)based on energy harvesting for nanonetworks is proposed.The energy harvesting technology is used to ensure energy supply of nanonode.Then,an energy state system model for energy changes of nanonode is established by extending Markov chain method and jointly considering the energy harvesting and consumption process of nanonode.The model captures the dynamic network behavior by probabilistic analysis of the overall network traffic and multiuser interference.In addition,a mathematical framework is developed to obtain the energy probability distribution of nanonode.Finally,the impact of different packet sizes on successful transmission probability,delay,throughput and energy consumption for ECP mechanism and other four error control strategies is investigated by means of simulation experiments.The other four error control strategies include Automatic Repeat reQuest(ARQ),Forward Error Correction(FEC),Error Prevention Code(EPC)and Hybrid Error Prevention Code(HEPC).The experimental results show that the performance of ECP mechanism in terms of delay,throughput and energy consumption is not as good as HEPC schemes,but compared with ARQ and EPC strategies,ECP mechanism can maximize the successful transmission probability while improve system throughput,and outperform ARQ and FEC schemes in terms of energy consumption performance.2.In order to adapt to the changes of actual network environment,improve the reliability of data transmission,and considering the problem of energy supply for nanonode,an adaptive error control strategies(AEC)is proposed through analyzing the suitable application scenarios of ARQ,FEC and ECP strategies,and combining the characteristics of nanonetworks and THz band.AEC can dynamically adjust the error control strategy used in data transmission to fit the changes of network environment based on changes of packet energy harvesting rate of nanonodes and instantaneous signal-to-noise ratio of wireless channel.In addition,the energy state system model of nanonode and the channel state prediction system model are established by the extended Markov chain method.According to the established two models,four performance indicators of AEC strategy,such as successful transmission probability,delay,throughput and energy consumption,are investigated and compared with other similar error control strategies(ARQ,FEC and ECP).The experimental results show that AEC strategy has better performance than the other three error control strategies in the above four performance indicators.