Extremely large-scale massive MIMO (XL-MIMO) is a promising technique for future 6G communications.However, existing far-field or near-field channel model mismatches the hybrid-field channel feature in the practical XL-MIMO system.Thus,existing far-field and near-field channel estimation schemes cannot be directly used to accurately estimate the hybrid-field XL-MIMO channel. To solve this problem, we propose an efficient hybrid-field channel estimation scheme by accurately modeling the XL-MIMO channel.Specifically,we firstly reveal the hybrid-field channel feature of the XL-MIMO channel, where different scatters may be in far-field or near-field region.Then, we propose a hybrid-field channel model to capture this feature, which contains both the far-field and near-field path components. Finally, we propose a hybrid-field channel estimation scheme, where the far-field and near-field path components are respectively estimated. Simulation results show that the proposed scheme performs better than existing schemes.
翻译:极大规模的大型MIMO(XL-MIMO)是未来6G通信的一个很有希望的技术。 然而,现有的远地或近地频道模型与实际的XL-MIMO系统中的混合现场频道特征不匹配。 因此,现有的远地和近地频道估算计划不能直接用来准确估计混合现场XL-MIMO频道。为了解决这一问题,我们建议了一个高效的混合现场频道估算计划,方法是精确地模拟XL-MIMO频道。 具体地说,我们首先揭示了XL-MIMO频道的混合现场频道特征,在那里,不同的分散分布可能发生在远地或近地区域。然后,我们提议了一个混合现场频道模型来捕捉这一特征,其中包含远地和近地路径组成部分。最后,我们提议了一个混合现场频道估算计划,其中分别估算远地和近地路径组成部分。模拟结果显示,拟议的计划比现有的计划要好。