LTE双层网中MIMO技术性能分析*

Femtocell技术以其较好的热点覆盖、较高的传输速率以及较大的网络容量，成为LTE网络中补充覆盖的重要途径之一。但同时，也造成了网络中复杂的CCI，严重影响了异构网络的性能。为了减少LTE双层网络中的CCI，提高网路容量，本文将基于MIMO的本征波束赋形、正交空时编码、天线选择技术应用于LTE双层网络，详细给出了无Femtocell覆盖半径、Femtocell最优密度以及Macrocell覆盖半径的精确数学表达形式，并对其所带来的干扰抑制效果进行了分析。通过仿真我们发现，相对于SISO来说，本征波束赋形的干扰抑制效果最好，可以使网络性能有个很大的提高，天线选择次之，正交空时编码所带来的增益最小，而当综合考虑性能增益以及复杂度的情况下，选择分集是一种比较合适的选择。

Performance analysis of MIMO in two-tier LTE network

Femtocell technology becomes an important way of the supplementary coverage of the LTE cellular mobile communication network for its better hotspot coverage, the higher transmission rate and the larger network capacity. However, it also brings about the complicated CCI in the networks at the same time, and this has seriously affected the performance of heterogeneous networks. In this acticle, in order to reduce the CCI and improve the capacity in the LTE hierarchical networks, Eigen Beamforming, Orthogonal Space-time Block Code and Antenna Selection technology are used in the two-tier network, the accurate mathematical expression of the no-coverage Femtocell radius, Femtocell optimal density and macrocell coverage radius are given, and the improved effect of the interference suppression are analyzed. From the simulation, we found that, compared to SISO, it is most beneficial for interference suppression about Eigen Beamforming, and it can greatly improve the network proformance, Antance Selection have a second effect, OSTBC bring the smallest performance gain. However, when we take into account the network gain and the complexity on the whole, the selection diversity is the better choice.