Research On Resource Allocation And Energy Consumption Issues In The Internet Of Things Based On Cognitive Radi

With the rapid development of the Internet of things,the number of nodes and the exponential growth of communication demand in the Internet of things have posed new challenges to the current wireless communication technologies and the limited wireless spectrum resources.In addition,there are many different types of nodes and services of which the demands for spectrum resources are also different.The existing fixed spectrum allocation strategy can not meet the growing spectrum demand of the Internet of things.The emergence of cognitive radio technology provides a more flexible allocation method compared with the currently fixed spectrum allocation policy.Cognitive radio can dynamically learn the changes of spectrum resources in the environment.On the premise of ensuring the normal work of primary users,cognitive radio can realize the efficient use of limited spectrum resources through spectrum sensing and flexible spectrum allocation.Cognitive radio can dynamically learn the changes of spectrum resources in the environment.On the premise of ensuring the normal work of primary users,cognitive radio can efficiently utilize the limited spectrum resource by spectrum sensing and flexible spectrum allocation.In addition,the introduction of cognitive radio technology to the Internet of Things(Io T)can dramatically improve the utilization of the spectrum resource.However,it brings additional energy consumption,such as energy consumption in the process of spectrum sensing.As the Io T terminal equipment is generally powered by battery,its own battery capacity is limited.Furthermore,replacing the battery requires labor and material resources.RF energy collection technology can collect RF energy sent by surrounding base stations,provide power to wireless nodes,and effectively solve the energy consumption problem of wireless nodes in Io T networks.In this paper,cognitive radio technology is combined with the Io T network,and how to carry out effective spectrum sensing and spectrum allocation in the Io T network based on cognitive radio is studied.By determining the optimal sensing task duration,sensing task allocation and spectrum allocation scheme,the system can obtain the maximum benefit or energy efficiency.In addition,RF energy collection technology is also introduced into the cognitive Io T network to provide energy for wireless nodes.By reasonably determining the time slot and transmission power allocated to each link,the system energy efficiency can be maximized.The main research of this paper is as follows:(1)A system model based on cognitive radio for spectrum sensing in an Io T network is built.Considering the energy consumption in the process of system spectrum sensing,a cross-layer and multi-channel cooperative spectrum sensing method based on heuristic algorithm is proposed.The heuristic algorithm is used to determine the optimal sensing time and task allocation scheme to maximize the energy efficiency of the system.The simulation results show that,the proposed method can reduce the computational amount and achieve the similar system energy efficiency compared with the exhaustive method by effectively determine the sensing time and assign the sensing tasks.(2)Considering the network structure characteristics of the Io T networks,the spectrum allocation problem in the heterogeneous Io T network based on cognitive radio is studied in this paper.By introducing the concept of channel granularity,combining with the information of spectrum sensing,and considering some other factors,such as the channel overlap,network overlap,and channel availability,a spectrum allocation algorithm based on genetic algorithm is proposed to allocate the available spectrum resources reasonably and effectively to avoid the network interference with the same frequency and to maximize the network benefits.The simulation results show that,compared with the spectrum allocation method based on random algorithm,the proposed method can effectively avoid the same frequency interference between the networks and achieve more network benefits.(3)Introducing the radio frequency(RF)energy collection technology into the cognitive radio-based Io T network,the cognitive users can use the collected energy for spectrum sensing and data transmission.The resource allocation problem of the cognitive Io T network is studied considering the energy consumption of each process.A resource optimization method for the cognitive Io T network based on genetic algorithm is proposed.Under some constraints such as energy consumption constraints,the system can achieve the maximum energy efficiency through the joint optimization of time slots and transmission power.The simulation results show that,the algorithm can achieve higher system energy efficiency than the random method.