本論文針對在無線網路中的動態頻譜存取提出了一個不以感知無線電(cognitive radio; CR)技術為基礎的協調式非偵測媒體存取控制(medium access control; MAC)協定，稱為分散式協調的動態頻譜競爭(distributed coordinated dynamic spectrum competition; DCDSC)協定。
在DCDSC協定中，所有的執照使用者(licensed user; LU)與非執照使用者(unlicensed user; UU)都同時具備有兩組收發機(transceiver)分別運作於一個共用的控制通道(common control channel)與數個執照資料通道(licensed data channel)，並且在對應的控制與資料訊框(data frame)裏存取控制與資料封包。LU會通知UU在下一個資料訊框裏將會使用哪一個通道來傳送資料，然後UU 傳送端會選擇其中一個沒有被LU使用的通道做為預定的傳送通道，並在控制訊框(control frame)的競爭區間(contention interval; CI)裏，以競爭的方式傳送MRTS(modified request-to-send)封包通知另一個UU接收端預定的傳送通道。LU的通道使用率會影響到UU可以使用的通道數，進一步也會影響到UU的資料傳送量(throughput)。每當UU成功地在CI中獲得通道使用權，便會在下一個資料訊框裡使用此通道傳送資料。這個運作會使得成功贏得通道的UU要浪費一段閒置的時間(wasted idle time)來等待進入下一個資料訊框，以便開始傳送資料。在目前的控制訊框裏無法成功贏得通道使用權的UU，會在下一個控制訊框裏再重試一次。另外，CI的長度將會影響到UU的傳遞延遲(delay)與浪費的閒置時間。本論文分析並且模擬DCDSC協定的效能包括了資料傳送量，傳遞延遲以及浪費的閒置時間。分析與模擬的結果，說明了本論文所提的DCDSC協定可以有很好的執行效能。

This thesis proposes a coordinated non-sensing medium access control (MAC) protocol in dynamic spectrum access networks namely distributed coordinated dynamic spectrum competition (DCDSC) protocol, which is not based on the cognitive radio technology. All licensed users (LUs) and unlicensed users (UUs) have two transceivers operating in a common control channel and licensed data channels to access control and data packets in the corresponding control and data frames respectively. LUs will inform UUs which channels will be used in next data frame. UU then select one of available channels as default channel for transmission and send modified request-to-send (MRTS) which contain the default channel to intended receiver by contending with each other during contention interval (CI) in control frame. The available channels which can be used by UUs will depend on the channel utilization of LUs and further affect the throughput of UUs. Whenever UU successfully obtains an available channel in a CI, it will start access the channel in next data frame. This will cause the wasted idle time for UUs which have successfully obtained channel and wait to enter next data frame. UU which couldn’t successfully obtain channel in current control frame will try to win the channel access in next control frame. Thus, the duration of CI will affect the delay and wasted idle time of UUs. We analyze and simulate the performance of throughput, delay and wasted idle time in DCDSC. The analytical and simulation results show that the proposed DCDSC performs very well.

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