标题: | 运用传送功率分配于欠定多输入多输出系统达到公平传输速率 Achieving Fair Rate by Transmit Power Allocation for Underdetermined MIMO Systems |
作者: | 温振鹏 李大嵩 电信工程研究所 |
关键字: | 欠定多输入多输出;功率分配;公平传输;fairness;underdetermined;power allocation;MIMO |
公开日期: | 2009 |
摘要: | 在无线通讯系统中,多输入多输出技术不需额外频宽及传输功率即能提高传输速率及改善传输品质。然而,在多用户多输入多输出上链系统的环境中,由于部分用户可能距离基地台较远或被障碍物所阻挡,以致通道增益较小,导致传输速率变差。在本篇论文中,吾人提出一个传送功率分配法达到公平的传输速率。吾人将一非线性最佳化问题转换成适当形式,将之套用到现有的演算法中。此公平化的机制可使得等效子通道增益较为均匀,因此等效通道矩阵会倾向于良置(well-conditioned)。因为在欠定多输入多输出系统中,有效率的解码器均基于球体解码器,因此通道矩阵有较小的条件数(condition number),可使得解码的复杂度降低。最后,吾人亦提出另一功用函数用于改善条件数,进一步降低运算复杂度。模拟结果显示吾人提出方法的有效性。 In wireless communication systems, multiple-input multiple-output (MIMO) technology offers significant increases in data rate and link range without additional bandwidth and transmit power. However, in uplink multi-user MIMO systems, some users will suffer from small channel gains due to being far away from the base station or blocked by obstacles in practical environments. This result in poor data rates for those users. In this thesis, we propose a transmit power allocation scheme with fair rate allocation for all users. We reformulate a nonlinear optimization problem to a modified form which can be applied to the existing algorithms. The proposed fairness scheme also leads to uniform sub-channel gains. Thus the equivalent channel matrix will tend to be well-conditioned. Since efficient decoders of underdetermined MIMO systems are based on sphere decoders, the decoding complexity can be reduced with a smaller channel condition number. Finally, we also propose an alternative utility function to improve the condition number, to further reduce the decoding complexity. Simulation results confirm the effectiveness of the proposed methods. |
URI: | http://140.113.39.130/cdrfb3/record/nctu/#GT079713531 http://hdl.handle.net/11536/44549 |
显示于类别: | Thesis |
文件中的档案:
If it is a zip file, please download the file and unzip it, then open index.html in a browser to view the full text content.