寬帶CDMA系統(tǒng)的自適應功率和速率控制性能分析
Performance analysis of adaptive power and rate control in wideband CDMA systems
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摘要: 該文研究一種新的自適應功率和速率控制方案,導出了采用這種方案的寬帶CDMA系統(tǒng)的誤比特率(BER)公式,并分別給出了系統(tǒng)在平坦衰落信道和多徑衰落信道中性能分析的數(shù)值結果。在這種方案中,移動臺根據(jù)衰落信道的變化自適應地調整其發(fā)射功率和傳輸速率,而衰落信道的變化通過一種新的遠程預測算法進行預測。首先將預測的總平均信道功率的概率密度函數(shù)劃分為若干個面積相同的區(qū)間,從而得出這些區(qū)間之間的門限值;然后通過與傳統(tǒng)功率控制技術相似的方式,將這些門限值用于自適應功率和速率控制。數(shù)值結果表明,采用這種方案能夠有效地提高寬帶CDMA系統(tǒng)的理論BER性能。Abstract: In this paper, a novel adaptive power and rate control scheme is studied, the BER. (Bit Error Rate) formula for the wideband CDMA system with this scheme is derived, and the numerical results of performance analysis in flat fading and frequency-selective channels are given respectively. In this scheme, the transmit power and rate are adapted by the mobile based on the variations of the fading channel. Firstly the predicted Probability Distribution Function (PDF) is divided into several regions equally, and the threshold values among these regions are got. Then the thresholds are used in adaptive power and rate control in a way similar to the traditional power control technique. The numerical results show that the theoretical BER performance of wideband CDMA system can be improved effectively by this scheme.
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