基于抽取濾波器多相分解的盲自適應符號同步算法
Blind Adaptive Symbol Synchronization Algorithm Based on Decimation Filters Polyphase Decomposition
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摘要: 針對軟件無線電系統(tǒng)中接收信號采樣時鐘獨立于發(fā)送信號時鐘的特點，提出了在抽取操作過程中實現(xiàn)符號同步，避免了在基帶階段進行內(nèi)插操作，以得到多相位信息的做法．利用過抽樣信號固有的多相位信息，通過最大似然相位誤差撿測算法，調(diào)整延時機構(gòu)，使信號傳輸延時匹配于延時分枝索引值，實現(xiàn)后續(xù)信號抽取輸出為最佳采樣值．利用級聯(lián)積分梳狀(CIC)濾波器和半帶濾波器(HBF)作為抽取濾波器，應用濾波器多相分解算法，降低了系統(tǒng)實現(xiàn)的復雜性和運算量．仿真結(jié)果表明，當信號傳輸延時匹配于延時分枝索引值時，相位誤差和延時分枝索引值將趨于穩(wěn)定．
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關(guān)鍵詞:
- 軟件無線電;抽取濾波器;符號同步;多相分解
Abstract: For the received signals were sampled at a fixed rate that is asynchronous with the data clock in software radio, we implement symbol synchronization during the process of decimation which replace general methods by using an interpolator in the baseband stage, and Maximum Likelihood(ML) timing synchronization techniques can be incorporated into the filters polyphase decomposition in a natural way. In order to match the timing delay of received signals to the data timing delay, the timing delay structure was adjusted by utilizing the timing error. Cascaded Integrator Comb (CIC) filters and HalfBand Filters (HDF) served as decimation filters that reduce the system complexity and computational burden to a certain extent. The numerical simulation results show that the value of timing delay structure will be converged to a constant with small fluctuation when the received signals timing delay matches the data timing delay, and the output from the last stage of FIR is the optimal sampled signals. -
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