Research On Robust Power Control In Two-tier Cellular Networks Based On Energy Efficiency Optimazation

With the rapid development of mobile communication technology,as the important architecture of 5G network,the two-tier cellular network has so many advantages,such as raising coverage area and reducing communication dead zone,improve network transmission capacity,transmission rate,improve network reliability and frequency spectrum resource utilization,saving energy and reducing consumption.As the typical representative of the two-tier network,micro-cell also brings new challenges to mobile communication network.Because the micro-cell network shares the same frequency band with the macro-cell network,the user and the base station will inevitably cause serious cross-layer interference and the inner-tier interference,which makes the communication network unable to communicate properly.In addition,the multiplicity and complexity of the actual communication environment bring a serious challenge to the normal communication of the user terminal.In addition,with the more flexible and open access mode of the future two-tier heterogeneous network,how to dispatch the base station resources and avoid the waste of resources becomes one of the urgent problems to be solved.Therefore,this paper designs robust power control scheme and sleep strategy scheduling under the uncertain factors in the two-layer heterogeneous network.Firstly,the paper studies the energy efficiency of communication system for block fading channel model.Because of the uncertain factors in the communication environment,the model is modeled as probability constraint,which is transformed by the indicator function to solve the optimization problem.In order to maximize the efficiency of the system,the optimal power and energy efficiency are obtained by using the Lagrange multiplier method to solve the proposed mathematical model.Secondly,the power control problem in 5G communication network is studied.The purpose of green communication is achieved through the combination of the base station sleep strategy and the power control scheme.If the base station satisfy the sleeping conditions,the base station enters the sleep mode.On this basis,the power control is carried out.At the same time,considering the uncertain factors existing in the communication environment,the problem of uncertainty optimization is transformed intoa deterministic problem by using the way of integration.Then,the three conditions of the base station sleep are used to verify whether there is a base station that is not sleep but meet the conditions,so as to achieve the goal of maximizing the income.Finally,the green communication problem in 5G network is studied.The method of combining the sleep strategy of base station with power control is proposed to maximize the revenue.In order to solve more easy,we regard the sleep indicator variable as a constant.Considering uncertainty problems in communication system,the worst case model is used to deal with uncertain constraints.Then the non-deterministic problem is transformed into a deterministic problem.At the same time,the optimal base station sleep strategy is obtained by using the Lagrangian function.