Bandwidth Utilization and Call Blocking Probability of OVSF Single-code Allocation with a Partial-loss Batch-arrival Model

Abstract

在第三代WCDMA 無線網路中，一個Node-B基地台的正交可變展頻(OVSF)編碼數量是珍貴而有限的，過去已有許多OVSF 編碼配置方法被提出來，並盡可能提供支援更多的用戶。本篇文章提出一個複數到達部分流失佇列模型，利用此模型來分析OVSF 單碼配置系統，並可藉此計算出部份流失率及頻寬使用率，這兩個重要的效能參數分別代表用戶的服務品質及系統業者的收益。經由模擬比較顯示這個模型似乎可以用來分析前述系統，對於WCDMA 無線網路建置時有所幫助。

The orthogonal variable-spreading-factor (OVSF) codes in a Node-B of the 3G WCDMA network are limited and valuable. Many works have devised OVSF code-allocation schemes to support as many users as possible. This paper proposes a batch-arrival partial-loss queueing model to evaluate the performance of the OVSF single-code allocation system and obtains the expressions of partial loss probability and bandwidth utilization, both of which are two important performance measures for the system. They respectively denote the quality of service for subscribers and the profit of an operator. Simulation results show that the proposed model appear to work, which should be helpful for constructing WCDMA networks.