LTE中Femtocell的联合信道与功率控制算法

Joint channel and power control algorithm for Femtocell in LTE

随着LTE中家庭基站的密集部署,会使家庭基站间产生严重的同层干扰,与此同时也会对边缘宏用户产生严重的跨层干扰。针对这两种下行干扰,提出了一种基于图论的信道分配和基于路损的功率控制算法相结合的方案。首先基于图论的知识构建干扰图,通过干扰图进行信道分配,有干扰的小区采用相互正交的信道,降低家庭小区间的同层干扰。然后在保证宏用户和家庭用户QoS的条件下,根据设定的信干噪比(SINR)门限值,设置Femtocell干扰标志,并根据信道质量(CQI)设置干扰级别,通过干扰级别进行对应的功率控制,最终达到消除家庭小区对宏用户跨层干扰的目的。仿真结果表明,该算法很好地提高了用户的SINR和吞吐量,同时保证了家庭用户和宏用户的QoS。

With the dense deployment of femtocell in LTE, it will cause serious intra-tier interference, at the same time, it will also cause serious cross-layer interference to the macro user equipment（MUE）. For both the downlink interference, this paper proposed a channel allocation scheme based on graph theory and path loss power control algorithm combined solution. For the inter-Femtocell interference （IFI） , the scheme was based on the knowledge of graph theory to construct the interference graph, and carried out the channel assignment by the interference graph, the presence of interference in the cell used orthogo- nal channels. Then, under conditions that guaranteed the MUE and Femtocell user equipment （FUE） QoS, according to the threshold of SINR, it set Femtocell interference flag and set interference level according to channel quality indication（CQI）. Finally it used the corresponding power control through interference level to achieve the purpose of eliminating cross-layer interference. Simulation results show that the proposed algorithm is very good for improving the user＇ s SINR and throughput, while guaranteeing the QoS of FUE and MUE.