Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/6135
標題: 跳頻編碼多工無線系統運用封包結合與干擾抵銷技術之效能分析
Performance Analysis of RS-Coded MFSK/FH-SSMASystems with Packet Combining and Interference Cancelling
作者: 曾釋瑾
Chin, Tseng Shih
關鍵字: Wireless Communication Systems;無線通訊系統;Frequency-Hopping Systems;跳頻通訊系統
出版社: 電機工程學系
摘要: 
隨著數位科技的進步,無線通訊系統的發展已可提供高的資料傳輸速率並應用到更複雜的架構中。近幾年,展頻多工系統亦即編碼多工系統已然成為無線科技中一項引人矚目的技術。在展頻多工系統中,系統用戶可以隨時使用系統所提供的頻寬,而不需做任何時間或頻段的調配進而達到有效使用頻寬的目的。展頻多工系統包含兩種基本的架構,分別為直接序列展頻多工系統以及跳頻展頻多工系統。在本論文中,將對跳頻展頻多工系統做較深入的探討。由於跳頻系統頻率之多樣性,跳頻展頻多工通訊系統被廣泛的用來抵抗多路徑之衰減。但多用戶之間的頻率干擾將使得系統用戶容量受到限制,因此許多用來解決多用戶干擾的方法被提出並且作廣泛的研究。在本篇論文中,我們提出一新的多用戶偵測方式用來抵銷多用戶干擾,藉以增加跳頻展頻多工系統的用戶容量。而對於所提出的多用戶干擾抵銷系統,我們針對其在瑞雷衰減通道下之系統效能作分析,並且與傳統及過去提出的多用戶干擾抵銷系統作比較。
同時,我們並提出一個結合錯誤更正碼與多用戶干擾抵銷系統的架構設計以改善系統之效能。所採用之方式為藉由結合所接收之兩種不同時間的封包資料並且運用李德所羅門碼於跳頻展頻多工通訊系統。除了分析系統效能,我們並且利用錯誤及擦掉處理的模式以增進系統之效能。最後,我們提出一個保留解碼架構技術以進一步改善系統之效能。

With the advent of digital technologies, the wireless communication systems have been developed that can support high data rate and more sophisticated applica-tions. Over the last years, spread-spectrum multiple access (SSMA), also named as code-division multiple access (CDMA), has become a attractive technique in the wireless technologies. In an SSMA system, a lot of users can be allowed to share the same frequency band simultaneously and can achieve efficient bandwidth utilization. There are two basic types of SSMA techniques, namely direct-sequence SSMA (DS-SSMA) and frequency-hopping SSMA (FH-SSMA). In this thesis, we will focus on the FH-SSMA systems. FH-SSMA wireless communication systems have gained much interest recently because of its frequency diversity and resistance to the near-far problem. Cochannel interference (CCI) is one of the dominant factors which results in reduced user capacity. Various techniques used to resolve the CCI problem have been extensively investigated. In this thesis, we propose an improved iterative interference cancellation scheme to increase user capacity in the multilevel frequency-shift keying (MFSK)/FH-SSMA systems. The performance of systems with the proposed interfer-ence cancellers over Rayleigh fading channel are analyzed and compared with those of the conventional and other interference cancellers. In addition, a modified scheme for the RS-coded MFSK/FH system with packet combining is proposed to improve the system performance. The performance of the RS-coded MFSK/FH-SSMA system by combining the two different received copies of the same packet is analyzed. Er-rors-and-erasures correction decoding technique exploits the power of RS codes and improve the performance of the system that results from erasing unreliable symbols prior to decoding. Moreover, a modified scheme with reserved decoding is proposed to further improve the system performance.
URI: http://hdl.handle.net/11455/6135
Appears in Collections:電機工程學系所

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