通常客訴主要發生在細胞邊緣客戶，以2G/3G而言，現場人員常使用改善方式之一，就是調整涵蓋區相關功率，相對LTE內類似的技術，就是CRE(cell range expansion)及SFR(soft frequency reuse)。本文對pico cell SFR的可用性深入研究，同時對SFR及CRE這兩項技術進行整合性的探討，分析其對下鏈路影響、限制、相互關係及都會區與郊區間差異，最後歸類一個簡單調整方法及建議值，供現場人員改善細胞邊緣使用者傳輸率之參考。 經由我們分析及模擬結果，SFR及CRE調整值都不宜太高。而SFR雖可改善細胞邊緣使用者傳輸率，但與平均傳輸率通常是trade-off；可是在郊區pico cell 通道品質較好的地方，pico cell SFR適當的調整值，對pico cell 5%使用者傳輸率可改善18%、平均傳輸率可改善2%，整個系統5%使用者傳輸率及平均傳輸率可提昇將近2%。另對pico cell CRE造成使用者服務中斷問題，搭配pico cell SFR使用，約有1 ~4%改善效果。至於我們歸納的簡單調整方式，經模擬顯示具可用性。 Customer complaints usually come from cell edge users. For 2G/3G complaints, one of the most commonly used improvement methods by on-site personnel is to adjust the correlation power of the covered area. This is relatively similar to the technologies within LTE, which are CRE (cell range expansion) and SFR (soft frequency reuse). This thesis is an in-depth study of the usability of pico cell SFR and also performs an integrated study of both the SFR and CRE technologies, analyzing their influences, restrictions, and interrelations for the down links and differences between urban areas and rural areas. And finally, conclude a simple adjustment method and recommended value for on-site personnel to use as a reference to improve the throughput of cell edge users. Our analysis and simulation results indicated that the adjusted value of both SFR and CRE should not be too large. Also, although SFR is able to improve the throughput of cell edge users, it’s usually a trade-off with the average throughput. However, at rural areas where there are better pico cell channel qualities, a suitable adjusted value of pico cell SFR was able to improve the throughput for 5% of pico cell users by 18% and improve the average throughput by 2%. The throughput of 5% of the users and the average throughput in the overall system were able to be increased by almost 2%. In addition, for pico cell CRE problems that caused the user to get blocked or dropped, when used with pico cell SFR, there was an approximately 1~4% improvement. As for the simple adjustment method that we concluded, simulation results showed that it was usable.
