| 一种改进的OFDM自适应比特及功率分配算法 |
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| 引用本文： | 薛金银,焦秉立.一种改进的OFDM自适应比特及功率分配算法[J].北京大学学报(自然科学版),2006,42(1):93-98. |
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| 作者姓名： | 薛金银 焦秉立 |
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| 作者单位： | 北京大学信息科学技术学院,北京,100871 |
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| 基金项目： | 富士通研究开发公司资助项目 |
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| 摘 要： | 自适应正交频分复用(OFDM)技术是根据各子载波在频率选择性衰落信道中不同的瞬时增益,动态地分配数据比特和发射功率,从而达到优化系统性能,提高频谱效率的目的.研究了发射总功率和系统误码率上限不变时传输比特数最大化(RA)的自适应算法.提出了一种有记忆迭代方法,能有效克服由于比特数的离散性导致的迭代发散现象,并据此提出两种改进的RA算法.仿真结果表明,和过去的RA算法相比,改进的功率注水RA算法以增加少量的迭代次数为代价,能获得接近于最佳RA算法的传输速率;而改进的等功率RA算法在相同传输速率情况下具有更低的运算复杂度.
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| 关 键 词： | 正交频分复用(OFDM) 自适应调制 注水原理 |
| 收稿时间： | 2004-11-25 |
| 修稿时间： | 2004-11-252005-06-03 |
An Improved Bit and Power Allocation Algorithm for OFDM Systems |
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| XUE Jinyin,JIAO Bingli.An Improved Bit and Power Allocation Algorithm for OFDM Systems[J].Acta Scientiarum Naturalium Universitatis Pekinensis,2006,42(1):93-98. |
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| Authors: | XUE Jinyin JIAO Bingli |
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| Institution: | School of Electronics Engineering and Computer Science, Peking University, Beijing, 100871 |
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| Abstract: | A new iterative method is proposed to overcome vibration in adaptive power and bit loading algorithms for wireless OFDM systems. The method is introduced into rate adaptive (RA) algorithms aiming at maximization of data rate under the constraint of total transmit power and bit error rate. Then two improved RA algorithms, named water-filling RA (WF-RA) and equal-power RA (EP-RA) algorithm respectively, are proposed. Simulation results show the improved WF-RA algorithm has approximately the same throughput as the optimal solution and the improved EP-RA algorithm has a lower computational complexity compared to the previous ones. Finally, the performance degradation due to imperfect channel state information is discussed. |
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| Keywords: | OFDM adaptive modulation water-filling |
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