Research And Implementation Of LTE Uplink Scheduling Algorithm Based On NS3

In recent years, with the rapid development of mobile communication technology, the demand for mobile data services are increasingly diversified. In the LTE system, the wireless resource management functions can utilize different resource scheduling algorithms to allocate the limited radio resources rationally so that the diverse needs for mobile data services can be satisfied efficiently.First of all, the paper gives a brief overview of the LTE system and the uplink resource scheduling process, including the FDD frame structure, SC-FDMA, Buffer State Report(BSR), Adaptive Modulation and Coding(AMC), Hybrid Automatic Repeat Request(HARQ). According to the NS3 LTE Scheduler interface specification, the scheduler scheduling process is designed in this paper.Secondly, in order to meet the requirement of continuous uplink resource allocation in a single cell,this paper propose grouping the resource blocks which are used in traditional scheduling algorithm. Because the existing scheduling algorithms cannot meet the needs of edge users Guaranteed Bit Rate(GBR), this paper proposes the GBR-PF algorithm. Firstly, determining the grouped resource blocks according to BSR reported by users, the GBR-PF algorithm allocates the RBG instead of RB to reduce signaling overhead. Then, this paper implements the RR-M,MT-M,PF-M on the platform NS3, and builds simulation models to test its performance, the results show that PF-M still has a high throughput on the premise of ensuring the fairness of users. Finally, to ensure the GBR of edge users, this paper adds GBR factor into PF-M scheduling priority of formula. When the average transmission rate lower than GBR, user will be forced to schedule. The GBR-PF on the platform NS3 is implemented, and simulation models to test GBR-PF and PF-M performance are built, results of which show that the GBR-PF algorithm can satisfy the needs of edge users GBR and edge user's throughput is promoted about 27.8% compared with PF-M algorithm.Finally, based on reusing frequency in multiple cells, this paper modifies GBR-PF to implement the GBR-PF-M algorithm based on soft frequency reusing scheme. Firstly, to determine the preferred frequency reuse scheme, this paper analyzes Hard Frequency Reuse(HFR), Fractional Frequency Reuse(FFR) and Soft Frequency Reuse(SFR) theoretically, while the SFR scheme is determined by testing the simulation model. Then, On the basis of GBR-PF algorithm, the resource blocks are redivided into M groups, where M is number of users and this grouping method reduces the complexity. At last, this paper realizes this scheme and builds simulation models on NS3, the results show that the GBR-PF-M +SFR scheme further improves edge user's throughput about 18.8% based on SFR.