Research On Resource Allocation Algorithm For MIMO-OFDMA System In High-speed Mobile Scenario

As 5G communication technology,MIMO and OFDMA have developed rapidly.They are being used in high-speed mobile communication system.What's more,with the increase of massive data flow,such as the video stream,the passengers' demands for data transmission rate and the quality of service are growing.Accordingly,allocating radio resources reasonably will have some practical values to solve the high-speed mobile communication system with respect to spectrum shortage and high energy consumption.Considering the particularity of high-speed mobile scenario,the resource allocation for OFDMA system and high-speed railway OFDMA system with large-scale antennas are studied.The resource allocation strategy which is used in high-speed mobile scenario is proposed to achieve low energy consumption and high energy efficiency.The main work of this paper is summarized as follows:(1)The problem of resource allocation in OFDMA system is studied.To solve high SNR and high computational complexity,Shen algorithm is improved and a resource allocation algorithm with low complexity and proportional fairness is presented,which is more suitable for wireless communication system in high-speed mobile scenario.In proposed algorithm,the actual channel conditions were taken into account and the user rate ratio is approximated as the proportion of the number of subcarriers.Then,the function expression of power allocation is deduced during the power allocation process.And the optimal power allocation strategy is obtained by some linear calculations.Simulation results show that the proposed algorithm has lower computational complexity and higher system throughput than Shen algorithm.(2)The research on resource allocation model in OFDMA system with large scale antennas is conducted.Firstly,the expression for system energy efficiency is given according to the channel characteristics of the large scale antennas system.Moreover,subcarriers,transmit power and antennas are jointly considered,the optimization objective is to maximize system energy efficiency under ensuring the fairness and minimum data rate.(3)Energy efficiency resource allocation for OFDMA downlink system with large scale antennas in high-speed mobile scenario is investigated.Firstly,the characteristics of the channel and the effect of Doppler shift are analyzed to design the channel state information feedback mechanism and calculate the inter-carrier interference power.Secondly,the resource allocation problem is modeled as a mixed integer programming problem for maximize system energy efficiency under the constraint of the fairness and minimum data rate.In the subcarrier allocation stage,the channel quality and carrier offset are both considered by using a hybrid subcarrier allocation method.And in transmit power and antennas allocation stage,the objective function in fractional form is equivalently converted into a concave function,and then the optimal allocation strategy can be obtained through multiple iterations.Simulation results demonstrate that,in high speed mobile scenarios,the proposed algorithm has a good performance in system throughput and energy efficiency.