不同的天線配置架構下分支相關效應影響MC-CDMA系統效能之分析研究

A Study on the Effect of Branch Correlation for MC-CDMA Systems under Different Configurations of Antenna Arrays

本篇論文提出新的多載波分碼多重近接（multi-carrier coded-division multiple-access, MC-CDMA）系統的位元錯誤率（bit error rate, BER）與使用者容量之效能表示式，其中應用了包括三角式（triangular）與線性式（linear）結構的天線配置；除此之外，亦假設通訊通道分支是工作於呈現具有相關性之Nakagami-m 分布的衰落環境之中。推導過程中。採取計算特徵函數（characteristic function, CF）的方式，以避開利用其他複雜的分析方法，藉以求得接收端輸出訊雜比（signal-to-noise ratio, SNR）的機率密度函數（probability density function, pdf）。最後經由數值分析之結果顯示，MC-CDMA 系統之效能確實會受制於不同之天線的配置方式與衰落通道的相關性所影響。 A new exact expression of BER (bit error rate) and user capacity performance for MC-CDMA (multi-carrier coded-division multiple-access) communication systems is proposed in this study. Different antenna configurations, including triangular and linear configuration antenna arrays, are applied. In addition, the branch is assumed to be operating in correlated Nakagami-m fading environments. The CF (characteristic function) is adopted to solve the PDF (probability density function) of the SNR (signal-to-noise ratio) at the MRC (maximal ratio combining) output instead of other complicated analytical methods. Finally, the numerical results obviously show that the performance degradation of the MC-CDMA system is sensitive to the correlation of fading channels, which is validated by comparing the results shown in certain published research [8].R222