臺灣博碩士論文加值系統

在蜂巢式無線通信網路中,頻道的資源是有限而珍貴的, 故對一特定區
域範圍中, 不可能提供無限多的頻道讓一套蜂巢式無線通信系統漫無限制
地享用, 因此, 如何以最少的頻道來滿足每一細胞服務區內客戶話務品質
的通信需求, 一直是令蜂巢式無線通信網路研究者所關注的重要議題。
本研究在第一部份將提出有效率的頻道分配演算法, 即數學模式化頻道分
配問題後, 用Lagrangean Relaxation程序為解題之基礎, 再以近似最佳
化的頻道分配先後次序, 來逐次分配頻道。在第二部份將對無線電台之傳
輸功率亦納入規畫的考量, 如此將驟增頻道分配問題的複雜度, 吾人將提
出一種兩階段的解題法, 來解決此一包含功率控制與頻道分配的問題, 在
第一階段先決定好基地台之傳輸功率, 第二階段再將先前所提出的頻道分
配演算法加以利用,期使系統中頻道的總需求量能更為降低。 在驗證了所
提出的幾個演算法之後, 演算法2是蠻值得加以推薦作為頻道分配的方法
。 此外, 用來作為功率控制的演算法A, B, C, 若結合演算法2去解問題,
將原演算法對頻道的使用提升3%,10%與36%的效能, 如此更證明了功率與
頻道分配問題同時考慮的好處。

Since communication channels are limited and valuable
resources in channelized mobile communication systems, it is
essential that channels be utilized in an effective and
efficient way. The same channels could be reused in different
cells with sufficient distance, where the effects of
interference between users of the same channel were negligible.
It then becomes an important and yet challenging problem for
designers of channelized mobile communications systems to
minimize the number of channels required subject to quality of
service constraints. The first part of this thesis is to
propose an effective and efficient channel assignment algorithm
to achieve the above objective. The problem is first formulated
as an integer programming problem. The Lagrangean relaxation
method is then proposed to solve the mathematical programming
problem. In the second part, radio port transmission power
control is taken into consideration jointly. The problem is also
formulated as an integer programming problem. A two-phase
solution procedure is proposed to solve the joint problem. In
the first phase, the transmission power of each radio port is
determined, while in the second phase the channel assignment
algorithms developed previously are applied. From
computational experiments, Algorithm 2 is recommended for
channel assignment. In addition, Algorithms A, B and C in
conjugation with Algorithm 2 achieve 3%, 10% and 36% improvement
on the total number of channels required over Algorithm. This
clearly demonstrate the advantage of considering power control
and channel assignment jointly.