Interference Mitigation in Spread Spectrum Systems Using Lapped Transforms

摘要

In this report, linear and non-linear transform domain filtering techniques are examined and proposed as a means of enhancing the inherent interference immunity associated with direct sequence spread spectrum communication receivers. This analysis begins with a review of block transform domain Wiener filters and is further developed in the lapped transform domain. The latter part of this report addresses the use of lapped transforms to transform the received data signal into the transform domain wherein adaptive excision is performed. System performance results are presented for a variety of channel conditions and compared to those obtained using orthonormal block transforms. These results demonstrate the improved performance and increased robustness with respect to jammer frequency and bandwidth of lapped transform domain excision techniques relative to similar algorithms based on non-weighted block transforms.