| As the standard of 4G with independent intellectual property rights,TD-LTE has attracted extensive attention when it is proposed.With the popularization of 4G base stations application,the development of TD-LTE technology has being gradually improved.Before the all-round popularization of 5G technology,TD-LTE is still one of the most efficient communication solutions.How to effectively allocate and manage wireless resources,ensure the service quality of system users and improve the system communication performance is an important research topic of TD-LTE system.The wireless resource allocation and management of TD-LTE system is completed according to the scheduling algorithm.Excellent scheduling algorithm can improve the system data throughput,improve the fairness between users in the system and ensure the system QoS service.Based on the basic working principle of TD-LTE,this paper researches the related technologies of uplink scheduling which focuses on the uplink scheduling algorithm.In order to satisfy the need of get the front area information in timely in emergency communications,,a targeted improvement scheme is proposed based on the current proportional fairness algorithm,and a simulation system is built to analyze and verify the improvement scheme.Finally,the algorithm is transplanted to the Power PC platform,which has been optimized and improved according to the actual needs.The specific work contents are as follows:(1)This paper researches the TD-LTE uplink scheduling system model,deeply analyzes the TD-LTE system architecture,frame structure,uplink physical resource mapping and other related technologies,studies the working principle of channel selective scheduling,and focuses on the uplink scheduling related technologies in TDLTE system.(2)The TD-LTE uplink time domain packet scheduling algorithm has been researched,and the advantages and disadvantages of maximum carrier interference ratio,polling and proportional fairness algorithms have also been analyzed.Through the constraints of delay and rate guarantee factor,a algorithm is designed based on the proportional fairness of QoS.According to comparative experiment,when the real-time service demand is 256 Kbps and the number of users is no more than 30,the fairness of the algorithm is improved.The packet loss rate and the proportion of real-time service transmission are better than the proportional fairness algorithm.The advantage is most obvious when the number of users is 15.The fairness is about 7% higher than that of PF algorithm,and the packet loss rate is decreased by 6%.With the increase of the number of users,the demand for QoS service transmission bandwidth is increased greater than the total system bandwidth,and the advantage gradually decreases.(3)The uplink frequency-domain resource allocation algorithm of TD-LTE has been researched,and the performance of frequency-domain resource allocation algorithms FME and RME has been analyzed.According to the problem of low spectral efficiency in the case of channel small-scale fading,OME resource allocation algorithm is proposed by changing of rate expansion factor.When the number of users is 10,it is improved about5.8% than RME algorithm,and the fairness is improved about 12%.Combined the proportional fairness algorithm based on QoS in time domain and the resource allocation algorithm in frequency domain,EOME algorithm has been proposed.Through simulation,when the real-time service demand is not greater than the total transmission bandwidth of the system,the packet loss rate decreases significantly.(4)The hardware platform of TD-LTE system has been implemented with the cooperative company.The design of hardware platform based on Power PC architecture?link layer software,and the uplink scheduling algorithm have been completed in the paper.The experiment show that: In the real-time service test with different rate requirements,the system performance in real-time service communication is better than PF algorithm,and the test result is consistent with the simulation results. |
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