| Summary: | 碩士 === 國立中山大學 === 電機工程學系 === 87 === Due to the increasing number of users, the limited bandwidth and frequency reuse cause the problem of cochannel interference in the modern wireless mobile communications. Additionally, the source amplitude is seriously faded due to the multipath propagation. Therefore, we must use the technology of signal processing to improve the system performance of the receiver. The paper investigates the structure of space-time signal processing to resolve the cochannel interference. The space-time signal processing not only uses the technology of time diversity, but also uses the antenna array signal processing to suppress the cochannel interference to achieve the optimal performance. But we find that in the multipath fading environment, the method in [16] can't suppress coherent interference effectively. To overcome this problem, we use the spatial smoothing method [18] to decorrelate the correlation of signals, and then use the eigenstructure interference canceler to suppress the coherent interference. Simulation examples are provided for illustrating the effectiveness of the proposed technique.
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