Theoretical Analysis of an MC-CDMA System in Cellular Environments

基於理論分析觀點研究蜂巢環境中之MC-CDMA系統

陳雍宗(Joy Iong-Zong Chen)

《科學與工程技術期刊》 6卷1期 (2010/03) Pp. 37-50

https://doi.org/10.7117/JSET.201003.0037

摘要

本篇論文對改良的蜂巢式多載波分碼多重近接(multi-carrier coded-division multiple-access, MC-CDMA)系統作系統效能之分析，其中利用擴展文獻[13]內容，針對MC-CDMA系統工作於區域之蜂巢中，並有12個蜂巢週遭之環境進行校能分析。分析過程中，介於本區蜂巢與相鄰蜂巢（考慮6個較近的蜂巢）不同幾何形狀進行說明於數值分析中。此一針對MC-CDMA系統之錯誤率的評估，係基於研究之理論分析爲出發點；其中之系統工作環境假設單一與多重之蜂巢結構，而且假設相關Nakagami-m之通道統計分布。傳統對於求取聯合機率密度函數(jointprobability density function, JPDF)是有某些程度之困難，爲了避免並簡化，利用涵蓋一般化之Laguerre多項式的聯合特徵函數，以決定聯合機率密度函數，其中對於MC-CDMA系統結合最大比例合成(maximal ratio combining, MRC)分集工作於多蜂巢環境，並且計入多重近接干擾量(multiple access interference, MAI)。

關鍵字

MC-CDMA ； 最大比例合成 ； 一般化Laguerre多項式 ； 相關Nakagami-m分布

並列摘要

By extending the scheme adopted by Chen [13], the performance of an improved cellular MC-CDMA (multi-carrier coded-division multiple-access) system for operation within a local cell, plus 12 surrounding cells in the first two tiers, is evaluated in this report. Herein, the impact of system performance with different geometrical structures of the local and the neighboring cells (the six furthest cells) is illustrated in the results from the number simulation implemented. The evaluation of error probability for an MC-CDMA system is investigated from the viewpoint of theoretical analysis, in which a working environment with both single-cell and multiple-cell configurations and correlated-Nakagami-m fading channel statistics is assumed. A joint characteristic function is applied to determine the JPDF (joint probability density function), including a generalized Laguerre polynomial. For the sake of simplicity, the difficult traditional methods for explicitly obtaining the JPDF are avoided. In this study, some new closed-form formulas for the average BER (bit error rate), with statistical calculation of MAI (multiple access interference) for an MC-CDMA system with MRC (maximal ratio combining) diversity operating in a multiple-cell environment, are also obtained.

並列關鍵字

MC-CDMA ； MRC diversity ； joint characteristic function ； generalized laguerre polynomial ； correlated-Nakagami-m fading