说明：  首先分析了GSM系统覆盖范围受限的主要因素，然后从技术上阐述了扩展小区覆盖的方法，最后提出了解决扩展覆盖的方案。
(First, we analyze the coverage of GSM system, the main factors is limited, and then elaborated on the expansion of the technical method of cell coverage, and finally put forward a solution to expand coverage options.)