巨細胞系統中適應不規則地形之頻道指配法-以傳播模式為基礎

Abstract

在本論文中,發展出一適應不規則地形之巨細胞頻道指配方法,該方法依據 各基地台場強之分佈及同頻干擾情形,並採用適應性局部搜尋演算法,進行 頻道指配,能使各基地台有效涵蓋面積儘量趨近不考慮同頻干擾時的結果, 也就是說該頻道指配法可有效增加基地台之有效涵蓋面積.為使該指配法 能適用於具有不規則起伏地形之環境,將使用適應環境電波傳播模型配合 實際環境之電子地圖來計算各基地台電場分佈及同頻干擾.該指配法實際 應用在台灣北區進行頻道指配,其成效不錯,可有效降低同頻干擾效應對有 效涵蓋區範圍之影響. In this research, a model-based channel assignment algorithm, using an adaptive local search algorithm, is developed to reduce the effect of cochannel interference on cell coverage. This assignment algorithm cooperated with a site-specificed propagation model can be applied to different propagation environments, such as an irregular terrain area.With the input of digital map,field strengths and carrier to cochannel interference ratio of each base station can be calculated by the propagation model. This algorithm has been applied to the northern part of Taiwan for channel assignment work and it shows an effective performance in reducing the cochannel interference.