混合式跳時/直序多重存取超寬頻系統進行正交分脈波多工技術之研究

Orthogonal Pulse Division Multiplexing for Hybrid TH/DS Multiple Access UWB Systems

施宗豐(Zong-Fong Shih)

指導教授 ： 沈義順

國立虎尾科技大學/工程學院/航空與電子科技研究所/碩士(2013年)

https://doi.org/10.6827/NFU.2013.00086

摘要

本論文中提出混合式跳時/直序超寬頻系統結合進行正交分脈波多工(OPDM)之研究。針對使用二位元相位位移鍵(BPSK)調變[1][2][3]採用傳統的跳時/直序系統來進行性能分析與模擬。此外，對雙正交脈波位置調變(BPPM)結合改良式的跳時/直序系統來實現模擬。本論文採用正交分脈波多工傳輸之技術的優點在於增加資料的傳輸速率。而使用TH/DS之技術是用於改善系統在多重存取時之性能。BPSK調變採用多脈波傳輸技術，使原本只能傳送一個位元的BPSK調變，轉變成能同時傳送Q個位元傳送，來增加資料的傳送速率。依據高斯近似(GA)分析的方法，推導出多重存取干擾(MAI)、訊框干擾(IFI)之變異數(Variance)和系統之平均位元錯誤機率(BER)。由模擬結果來驗證理論分析。2M-ary PPM是將BPSK調變與PPM調變結合而成，並且採用在OPDM系統中，而結合PPM是為了藉由增加調變階數(N=2M)來增加資料的傳送速率。分析與模擬是採用實際超寬頻衰減通道(CM1-CM4)與附加白色高斯雜訊(AWGN)。
為了對系統的性能進行公平的比較，脈波寬度(Tp)被固定為0.7ns，也就是固定傳輸訊號之頻寬；並且固定資料傳輸速率。藉由數值分析和模擬結果可以得知，當其他系統參數均固定，用戶數(Nu)的增加會減弱系統性能。藉由模擬結果可以驗證系統數學理論分析。考慮OPDM之技術使用BPSK調變與BPPM調變，當固定資料傳輸速率的情況下，同時傳送的脈波數越多，系統效能會明顯的改善。

關鍵字

跳時/直接序列 ； 正交分脈波多工 ； 高斯近似法 ； 訊框干擾 ； 多重存取干擾 ； 多重路徑衰落通道

並列摘要

In this thesis, the orthogonal pulse division multiplexing (OPDM) for hybrid TH/DS UWB systems is studied. Using the binary phase shift keying (BPSK) modulation, the performance analysis and simulation for the conventional TH/DS system are carried out. In addition, the simulation of the modified TH/DS system combined with BPPM modulation is implemented. The advantage of employing OPDM is to increase the transmission rate of message. Applying the TH/DS multiple access technology to the examined system is used to improve the system performance. Instead of only one data bit carrying in the transmitted BPSK modulation, the benefit of the proposed system using OPDM is Q bits can be simultaneously transmitted to increase the transmission rate. Based on the analytical method of Gaussian approximation, we derive the variance of multiple access interference, inter-frame interference, and system average bit error rate. The simulation results are used to verify the analytical results. The N-ary bi-orthogonal pulse position modulation (BPPM), which is the combination of BPSK and pulse position modulation (PPM), is adopted in the investigated OPDM system in which the modulation level (N) of the proposed system can be increased. The actual ultra-wideband fading channel (CM1, CM3) and additive white gaussian noise (AWGN) is used in the simulation and analysis.
In order to make the fair comparisons for the system performance, the pulse width Tp is fixed to be 0.7ns, i.e., fixed the bandwidth of the transmitted signal, and the data transmission rate is fixed. From the numerical analysis and simulation results, when the other parameters are keeping the same, the increase the number of users (Nu), the more degrade the system performance. The simulation results are carried out to verify the theoretical analysis of the proposed system. Considering the OPDM schemes using BPSK and BPPM modulations and having the same data transmission rate, the number of simultaneously transmitted pulse is increased, the system performance is improved obviously.

並列關鍵字

Time Hopping (TH)/ Direct Sequence (DS) ； orthogonal pulse division multiplexing (OPDM) ； Gaussian Approximation (GA) ； Inter Frame Interference (IFI) ； Multiple Access Interference (MAI) ； Multipath Fading Channels

參考文獻

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