在感知無線電下的重疊式和隱匿式傳輸

Abstract

在感知型無線電環境下，我們用三種技術去做傳輸且使得次要傳輸者的傳輸可以達到最佳化且限制對主要傳輸者的碰撞，其中包含重疊式傳輸，隱匿是傳輸，和結合重疊式傳輸和隱匿式傳輸的方法。 在知道主要傳輸者們的平均動作但不知道確切動作的條件下，我們用重疊式傳輸的方法來傳輸資料。我們用主要傳輸者的電視使用率分佈曲線和特性分佈曲線去找到一個最佳的封包長度來達到最好的吞吐量。 在次要傳輸者不知道主要傳輸者有沒有再使用通道但知道主要傳輸者的確切位置的條件下，我們用星球學理軌道的觀念和隱匿式的傳輸方法來找到最少的中繼點數和最佳的路徑。 在次要傳輸者能經由偵測漏電功率來知道主要使用者的確切動作的條件下，我們用結合重疊式和隱匿式的方法來傳送資料。經由感測主要使用者的漏電功率，次要使用者可以調整他的功率來達到最大的訊雜比和最大的容量。

In a cognitive radio network system with a collision constraint of primary user, approaches using the overlay, underlay, or the combination of the underlay and overlay methods have been purposed to optimize the transmission of the secondary user. Under the condition that the secondary user knows the general actions but not the exact actions of the primary users, an overlay method was purposed. In this overlay method, both the TV utility distribution (TUD) and the characteristic distribution (CD) of primary users were used to find an optimal frame length with highest throughput. Under the condition that the secondary user has no idea whether the primary user is using the channel or not but knows the exact locations of primary users, an underlay method based on the concept of orbits in astronomy was developed to find the least number of relay and the optimal routing. Under the condition that the secondary user can have the exact actions of the primary user by detecting the leakage power of primary user, an approach utilized both the overlay and underlay method was purposed. By sensing the leakage power of the primary user, the power transmitted by secondary user was adjusted to maximize the SNR and the capacity of the secondary user.