應用於結合多向度跳頻/多頻鍵移信號的非線性法則之研究

Abstract

本論文中我們對三類非線性接收器就其反干擾能力做了詳盡的分析。快速 跳頻－多頻鍵移(FFH/MFSK)的信號接收已有不少人從事過其反干擾能力分 析。 大部份的FFH/MFSK非線性接收器都需要額外的訊息(side information)－如通道的瞬時訊號雜音比－以便對不同向度(diversity branch) 收到的訊號做適當的合成。本論文所提出的三類FFH/MFSK接收器 則需要此類額外訊息，因此不會有對額外訊息估測誤差所造成的錯誤。本 論文對三類接收器的分析，不但導出各別的錯誤率 (bit error probability) 並得到了簡單且相當準確的錯誤率之上下限。我們分析和 模擬的結果都顯示了:(1)這三類接收器反干擾的能力皆相當接近理論上最 佳的反干擾接收器，(2)這三類接收器中其反干擾能力的優劣順序分別是( i)修正型自正規化(modified-self-normalizing)接收器， lf- normalizing)接收器，和(iii)比值(ratio-statistics)接收器。 從計算 機的模擬數值中,我們發現到假如系統的E_c/N_o 不小於 25dB的話,則將 熱雜訊忽略所得到的數學分析結果應相當準確。 This thesis examines the bit error rate (BER) performance of three classes of nonlinear diversity combining rules for FH/ MFSK signals to combat band multitone jamming. None of three classes of diversity combining rules requires additional acknowledge of the signal or jammer level, and thus they are not susceptible to errors incurred in measuring side information. Among the three classes of combining rules under investigation, the modified self-normalizing combining rule has the best BER performance, followed by the self-normalizing combining rule and then the ratio-statistic rule. Moreover, a member of the first class of rules is shown to yield error probability performance the same as that of a hypothetical suboptimal receiver studied by Levitt. Our simulation results also indicate that the analysis with the thermal-noise-free assumption yields excellent performance estimations if the associated $E_c/N_0$ is no less than 25 dB.