Location management strategies significantly affect the performance of wireless mobile networks.
This study investigates location management strategies in mobile wireless networks.

The first part of this study proposes a distributed location management strategy,
based on a distributed location information database (LID) architecture, in which
the traffic and load for updating and finding the locations of the mobile hosts are
evenly distributed among the LIDs. The average communication cost of the proposed
sliding-frame strategy is then analyzed, without considering visitor location register (VLR)
traffic, and shown to be always less than or equal to that of the strategy proposed by
G. Krishnamurthi et al. Numerical results are then shown and demonstrate that the proposed
strategy incurs a significantly lower average communication cost than the strategy proposed
by G. Krishnamurthi et al. when the average call to mobility ratio of the mobile hosts is low to medium.

The second part explores properties of the sets of LIDs based on the proposed distributed LID
architecture, when they are queried by the MSCs to fulfill query requests for the locations of
the mobile hosts. The average communication cost of the proposed strategy when using VLR traffic is analyzed,
and shown to be always lower than or equal to that of the strategy proposed by G. Krishnamurthi et al.
Finally, numerical results are presented, showing that the proposed sliding-frame strategy has a
significantly lower average communication cost than the strategy proposed by G. Krishnamurthi et al.,
when the average call to mobility ratio of the mobile hosts is low to medium and the number of replications
of each piece of location information is medium to large.

The third part explores the average database response time of LIDs. An analysis of the average database
response time of LIDs indicates that the proposed sliding-frame strategy can manage the same amount or
more traffic than the strategy proposed by G. Krishnamurthi et al. The average database response time
of the proposed strategy is analyzed, and shown to be always lower than or equal to that of the strategy
proposed by G. Krishnamurthi et al. The upper bound on the total request arrival rate is then analyzed.
Finally, numerical results are presented, and indicate that the proposed sliding-frame strategy has a
significantly lower average database response time than the strategy proposed by G. Krishnamurthi et al.,
when the average call to mobility ratio of the mobile hosts is low to medium and the number of replications
of each piece of location information is medium to large.

隨著無線行動網路使用者的增加，貯存使用者位置資訊的資料庫負載也增加，在降低資料庫負載的同時，
也讓資料庫系統具有容錯的能力，必須仰賴一個設計良好的位置管理策略。使用分散式資料庫
架構來管理使用者位置資訊，可以提供資料庫系統容錯能力和分散負載於所有的資料庫中。
因此本博士論文主要分成三個部分，研究分散式的資料庫架構下有關位置管理的相關議題。

在本論文的第一部分，我們提出了一個新的位置管理策略稱之為滑動框架策略，這個策略可以讓更新移動手機位置資訊和尋找
被呼叫移動手機位置資訊的訊號流量，平均的分散在貯存位置資訊的所有資料庫中；IS-41 是現行常用的通訊協定之一，在這個通訊協定中
資料庫系統是一個雙層的資料庫結構，上層為家位置位置暫存器，下層為訪問者位置暫存器，在不考慮訪問者位置暫存器訊號流量的條件下，
我們分析平均的通訊訊息代價而且證明滑動框架策略比 G. Krishnamurthi et al. 所提出的策略有更低的或者是相同的平
均通訊訊息代價；在
代入相關變數一些數值後，可以得知，若移動手機從一個位置區域移到下一個位置區域所需的平均時間內，這個移動手機
被其他移動手機呼叫的次數很少時，則滑動框架策略會比 G. Krishnamurthi et al. 所提出的策略，明顯有較低的平均通訊訊息代價。

在本論文的第二部分，我們將處理一個詢問要求時，所有被查詢的一些資料庫，定義為一個詢問集合，
以資料庫總數能否被資料庫複製個數所整除的前提下，我們發現，詢問集合在不同的狀況下，會有一些不同的特點，
這些特點在此被說明且證明；在這個部分，我們在考慮訪問者位置暫存器訊號流量的條件下，重新分析平均通訊訊息代價
而且證明滑動框架策略比 G. Krishnamurthi et al. 所提出的策略，有更低的或者是相同的平均通訊訊息代價；在
代入相關變數一些數值後，可以得知，在移動手機從一個位置區域移到下一個位置區域所需的平均時間內，若這個移動手機
被其他移動手機呼叫的次數很少時，則滑動框架策略會比 G. Krishnamurthi et al. 所提出的策略，明顯有較低的平均通訊訊息
代價；或者是複製
移動手機位置資訊的資料庫個數增加時，滑動框架策略會比 G. Krishnamurthi et al. 所提出的策略，明顯有較低的平均通訊訊息代價。

在本論文的最後一個部分，我們研究位置資訊資料庫的平均反應時間，經由分析位置資訊資料庫的平均反應時間，
我們證明滑動框架策略比 G. Krishnamurthi et al. 所提出的策略，可以處理相同或者是更多的訊號流量，而且滑動框架策略
比 G. Krishnamurthi et al. 所提出的策略，
有相同或者是更少的平均資料庫反應時間；另外我們也分析資料庫系統所能處理訊息流量的上限值，並計算出此上限值；
在代入相關變數一些數值後，可以得知，在移動手機從一個位置區域移到下一個位置區域所需的平均時間內，若這個移動手機
被其他移動手機呼叫的次數很少時，則滑動框架策略會比 G. Krishnamurthi et al. 所提出的策略，明顯有較低的平均資料庫反
應時間；或者是複製
移動手機位置資訊的資料庫個數增加時，滑動框架策略會比 G. Krishnamurthi et al. 所提出的策略，明顯有較低的平均資料庫反應時間。

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