Abstract
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)