本論文研究一個建立於感知無線電網路(Cognitive radio network)架構上的合
作式通訊系統，協力式感知無線電網路(Cooperative and Cognitive Radio networks,
CCR)。該系統中包含了主要使用者(Primary user)和次要使用者(Secondary user)，
次要使用者以感知無線電的重疊式(Overlay)形式在幫助主要使用者傳送訊號的同
時，亦分享主要使用者提供的無線資源傳輸自己的資料。網路中，次要使用者以
解碼後前送(Decode and Forward, DF)幫助主要使用者傳遞信息，主要使用者經過次
要使用者幫助構成一個合作式通訊系統可視為一個等效的多重輸出單一輸入系統
(Multi Input Single Output, MISO)，增加主要使用者的空間分集(spatial diversity)降
低中斷機率，增加傳輸的可靠度。次要使用者幫助主要使用者之餘，在確保主要
使用者的傳輸中斷機率低於目標值的前提下，同時也可以發射次要使用者自己要
傳送的訊息，以此獲得使用頻譜的權利。次要使用者可根據主要使用者以有限位
元回授資訊，回授主要使用者直進路徑的訊號訊雜比資訊，進一步對中繼傳輸的
主要使用者繼轉傳信號以及本身信號之間的傳送功率做精確的功率分配，維持主
要使用者的通訊品質在特定標準同時儘可能提升次要使用者資料傳輸量增加頻譜
使用率。

This thesis investigates cooperative communication under the framework of cognitive
radio network, which consists of primary and secondary users(PU & SU). The
cooperative and cognitive radio network (CCR) adopts overlay dynamic spectrum
access, That is, the SU simultaneously assists PU’s transmission and transmits its own
message using spectrum shared by primary user. The secondary user adopts
decode-and-forward (DF) relaying to assist the primary user in transmitting message.
With secondary user’s assistance, the cooperative system can be treat as an equivalent
multiple input single output (MISO) system to attain the spatial diversity of the primary
user. The virtual MISO system can reduce the outage probability and enhance the
transmission reliability. Under the requirement on primary user's transmission quality,
secondary user transmits both user’s signals simultaneously, so that the secondary
acquires authority to access spectrum. Based on limited feedback regarding SNR of link
between primary transmitter and receiver, secondary user allocates transmission power
of primary signal and secondary signal to increase throughput and spectrum efficiency
of SU subject to satisfying PU’s outage constraint.

論文審定書............................................................................... i
摘要.......................................................................................... ii
Abstract.................................................................................... iii
第一章 簡介............................................................................ 4
第二章 相關背景.................................................................... 7
2.1 感知無線電........................................................................ 7
2.2 合作式通訊........................................................................ 9
2.3 前人的研究...................................................................... 10
第三章 系統模型.................................................................. 12
3.1 傳輸行為模式.................................................................. 12
3.2 主要使用者中斷機率分析.............................................. 14
3.3 次要使用者資料傳輸量分析.......................................... 17
第四章 功率分配設計.......................................................... 19
4.1 回授資訊設計.................................................................. 20
4.2 對應回授信號的功率分配.............................................. 21
4.3 對整體主要使用者系統的功率分配.............................. 23
第五章 模擬結果與討論...................................................... 27
第六章 結論.......................................................................... 33
參考文獻................................................................................ 34
附錄........................................................................................ 35

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