Research On The Radio Resource Management Algorithms For LTE/LTE-a System

As the long term evolution technology of3G telecommunication system, LTE/LTE-Advanced has been receiving extensive attention by the academia and industry. The targets of mobile communication development are higher data transmission rate, better coverage and larger capacity. To attain higher data transmission rate, on the one hand, many innovative technologies based on MIMO-OFDMA are adopted by LTE/LTE-Advanced system. On the other hand, how to elevate the efficiency of radio resource utility under the limited resources and existing technologies, which means that how to design the radio resource management scheme that can be work efficiently, become a key technology to the system performance.Radio resource management technologies of TD-LTE/TD-LTE-Advanced system are studied in this paper. The innovative research achievements are listed as follows:(1) In LTE system, it is very necessary to support various traffic types and different traffics have heterogeneous requirements of QoS, So how to guarantee the heterogeneous QoS requirements of different traffics is a key technology. In this paper, a model that considers the QoS of multi-traffics is designed and a sub-optimal multi-dimension radio resource allocation scheme based on the utility function is proposed. In the scheme, we put the time-frequency resource allocation, admission control and load control problem together to build the model. Firstly, a satisfaction function is defined to descript heterogeneous QoS requirements. And secondly, users are classified according to their satisfaction function. Then different resource allocation strategies are applied to different user set. By this method, in the condition of sacrificing little system throughput performance, we get a better performance of user satisfaction degree.(2) The multi-antenna adaptive transmission is a key technology in LTE/LTE-Advanced system. To the problem of how to make full use of space domain resources, on the one hand, a single-layer and multi-layer adaptation scheme is proposed. Because we get the eigenvalue of user channel matrix by solve a polynormial equation instead of by the SVD of matrix and consider the inter-layer interference, the scheme has a lower computation complexity and more accuracy. On the other hand, we design a SU-/MU-BF adaptation scheme that not only consider the large-fading channel, but also put the fast-fading channel into account by the user correlation. Simulation results show that the accuracy of adaptive adjugement was improved.(3) To avoid the inter-cell interference to the cell edge users when LTE network is constructed on the same frequency, a modified SFR algorithm is designed based on the traditional SFR algorithm. The algorithm gives a higher priority to the cell edge users under the condition of guaranteeing the cell centre users and can get a good balance between the cell centre users and cell edge user performance. Because the problem of interference coordination can be equivalent to a constrained problem of radio resources, it is essentially belongs to the problems of radio resource allocation.(4) We can improve the performance of cell edge users by the interference coordination algorithm, but it is at the cost of experience of cell center users. The cooperation MIMO technique not only can improve the performance of cell edge users, but also develops the experience of cell center users. The coorperation MIMO is an extend utilization to the traditional space domain resource. In the paper, we compare the throughput performance of downlink JT-CoMP system and SU-/MU-BF adaptive scheme in LTE-Advanced system. To the uplink system, a PF algorithm based on the orthogonality of user channel matrix is studied. The performance of SIMO, V-MIMO and JR-CoMP is compared by the system simulation.