In pursuit of enhanced quality of service and higher transmission rates, communication within the mid-band spectrum, such as bands in the 6-15 GHz range, combined with extra large-scale multiple-input multiple-output (XL-MIMO), is considered a potential enabler for future communication systems. However, the characteristics introduced by mid-band XL-MIMO systems pose challenges for channel modeling and performance analysis. In this paper, we first analyze the potential characteristics of mid-band MIMO channels. Then, an analytical channel model incorporating novel channel characteristics is proposed, based on a review of classical analytical channel models. This model is convenient for theoretical analysis and compatible with other analytical channel models. Subsequently, based on the proposed channel model, we analyze key metrics of wireless communication, including the ergodic spectral efficiency (SE) and outage probability (OP) of MIMO maximal-ratio combining systems. Specifically, we derive closed-form approximations and performance bounds for two typical scenarios, aiming to illustrate the influence of mid-band XL-MIMO systems. Finally, comparisons between systems under different practical configurations are carried out through simulations. The theoretical analysis and simulations demonstrate that mid-band XL-MIMO systems excel in SE and OP due to the increased array elements, moderate large-scale fading, and enlarged transmission bandwidth.

翻译：为追求更高的服务质量与传输速率，中频段频谱（如6-15 GHz频段）通信与超大规模多输入多输出（XL-MIMO）技术的结合，被认为是未来通信系统的潜在使能技术。然而，中频段XL-MIMO系统引入的特性为信道建模与性能分析带来了挑战。本文首先分析了中频段MIMO信道的潜在特性。随后，在回顾经典解析信道模型的基础上，提出了一种融合新型信道特性的解析信道模型。该模型便于理论分析，且与其他解析信道模型兼容。基于所提出的信道模型，我们进一步分析了无线通信的关键性能指标，包括MIMO最大比合并系统的遍历频谱效率（SE）与中断概率（OP）。具体而言，我们针对两种典型场景推导了闭式近似解与性能界，以阐明中频段XL-MIMO系统的影响。最后，通过仿真比较了不同实际配置下的系统性能。理论分析与仿真结果表明，得益于阵列单元数量的增加、适度的大尺度衰落以及扩大的传输带宽，中频段XL-MIMO系统在SE与OP方面表现优异。