超寬頻帶系統(UWB)使用了一片相當巨大的頻寬。 這個巨大的頻寬和微波存取全球互通系統(WiMax)所使用的頻寬重疊，這造成了同頻帶通道干擾(CCI)。 我們使用認知微波技術(cognitive technology)中的主動干擾消除的技術(AIC)去解決這個問題。 UWB 的系統會偵測到WiMax 的訊號並且避免在同頻帶上面傳輸。這看起來的確是解決了這個問題。 然而我們在使用AIC 的時候做了一個突破。不止讓WiMax 系統在頻寬重疊的地方收到的訊號呈現一個凹陷下去的的訊號，
而且還可以在這頻寬重疊的地方傳送訊號。 因此,UWB 系統不用再停止傳輸。這項成就是歸功於AIC 的架構。 然而我們遇到一個嚴重的問題：如何把在頻寬重疊部分的訊號解回來?
因為這裡的訊號會遭受到嚴重的CCI，我們很難把訊號解回來。 如果我們沒有把CCI 解開，則CCI 所造成的影響和AWGN 加強的相同。 很明顯地，解回來的效果會相當的差。 因此，我們如何把訊號從CCI 狀況解回來將是接下來的重點。我們最後嘗試的方式是把現行的MIMO 技術拿來試試看。 是否每一種技術遇到CCI 的問題都無法解決? 最後我們遇到一種HLST 的技術。 雖然這項技術在多天線的時候效能不如VBLAST，傳送端和接收端天線的數目必須大於一個數字。
然而HLST 卻有優越的效能在抵抗CCI。這篇論文的最後我們加上了UEP 的技術，使得HLST 的效能更上一層樓， 並且用傳送圖片的方式來驗證。

The system of UWB use a huge frequency spectrum. This huge section of frequency overlap the section of WiMax which results in cochannel interference(CCI). We use the
Active interference cancellation (AIC) of cognitive technology to solve this problem. The system of UWB will detect the signal of WiMax and avoid to transmit in the
overlapped section of frequency spectrum. It seems to solve this problem. However, we make the paradigm shift when using the technology of AIC. Not only make a notch in
the overlapped section when the system of WiMax received the signal, but also transmit some signal in the overlapped section. Thus, the system of UWB do not have to suspend
for transmitting. This achievement distribute to construction of AIC. However, we encounter a serious problem: How to decode the signal back which situates in the overlapped section?
Because the signal will suffers from serious CCI, we hard to decode it back. If we do not disentwine the CCI, the influence of CCI is the same as the enhancement of AWGN.
It is obvious that the performance of decoding is pretty poor. Thus, how can we solve the signal from the CCI situation that is the following point. Finally, we take some technology of the MIMO system to try to solve this problem. Whether each of the technology has poor performance when it encounters the problem of CCI? We find a technology of horizontally layered space-time coding(HLST) at last.
Although the performance of HLST is worse than VBLAST, the numbers of transmitter and the receiver are both above some number. There is a better performance of HLST to resist the CCI. And in the last of this thesis, we add the technology of Unequal error protection(UEP). It makes the performance of HLST more better. We certify this by transmitting the images.
Index Terms- Active interference cancellation(AIC) Co-channel interference(CCI) Unequal error protection(UEP) Multi input multi output(MIMO) horizontally layered
space-time coding(HLST)

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