Research On 3GPP LTE Uplink Power Control Technology

With the traffic requirement of wide bandwidth, fast data rate, high quality and low delay, 3GPP advanced the next communication system-Long Term Evolution project. As a key technology of LTE, uplink power control provides lower interference to neighbor cell, larger cell coverage, improves system throughout and meets requirement of users. Until now, there are still some problems remain unresolved on uplink power control technology. Firstly, the compensator option of intra-cell power control is lack of flexibility, which leads to low efficiency of cell-center user and affects cell throughout. Otherwise, interference to neighbor cell is not quantified, so it is difficult to scale and control the interference level to neighbor cell. Secondly, the adjusted quantity of inter-cell power control is lack of flexibility and rationality, which affects the mitigation of neighbor cell interference; otherwise, the signaling spending of overload indicator is too large to the communicate among cells easily, it finally affects the system performance.Based on the deep analysis of LTE uplink power control technology and concentrated on two classes of intra-cell and inter-cell power control, we propose an intra-cell power control scheme based on adaptive compensator, and then an overload indicator inter-cell power control scheme based on path loss difference is proposed. The following is to realize a better performance of mitigating inter-cell interference, we add resource allocation to the scheme, and propose an inter-cell interference coordination algorithm based on the combination of high interference indicator and overload indicator. Main work and contributions of this dissertation are outlined as follows:1. An intra-cell power control scheme based on adaptive compensator is proposed. Based on the analysis of an intra-cell single user and quantification of interference to the strong neighbor cell, we get the relationship between variation of path loss compensator and path loss. Then the paper proposes the intra-cell power control scheme based on adaptive compensator. AT last, with the practical application scenario analysis of dynamic variation of intra-cell users’ number and alternation of traffic model, the paper proposes the correlative adaptive scheme. Simulation results showed that the proposed scheme had higher cell throughout and average users’SINR than traditional power control scheme and fractional power control scheme.2. An overload indicator indicated inter-cell power control scheme based on path loss difference is presented. According to deep analysis of inter-cell interference and improvement of current overload indicator, we introduce path loss difference to express the contribution to overload indicator and set according power control adjusted quantity based on traditional inter-cell power control scheme and other current based on OI scheme. Simulation results show that the new algorithm has higher system throughput and a high level of cell edge users’SINR.3. An inter-cell interference coordination algorithm based on the combination of high interference indicator and overload indicator is proposed. Based on analysis of the previously chapter and addition of resource allocation, the paper introduces improved high interference indicator to combine with improved several threshold overload indicator for inter-cell interference coordination. Simulation results show that the new algorithm has excellent performance on cell throughout and cell edge user throughout.Schemes proposed in the paper provide project from theory to practice for intra-cell power control and inter-cell power control. There is some theoretical significance and reference value for the design of LTE uplink power control project.