Software-defined radio architectures for interference cancellation in DS-CDMA systems

Third-generation wireless systems call for strategies that can improve achi evable performance and data rates while providing flexibility and affordabi lity. Software-defined radio technology is promising to provide the require d flexibility in radio frequency, intermediate frequency, and baseband sign al processing stages. Baseband signal processing techniques such. as interf erence cancellation for direct-sequence code-division multiple access syste ms have the potential to provide the higher performance requirements of 3G systems. With advances in digital signal processor technology, the gap betw een the complexity of interference cancellation algorithms and available pr ocessing speeds is narrowing. However, 3G system requirements are ever push ing the envelope of signal processing algorithms required, including multi- user detection schemes, that are considered to be attractive and viable can didates. WINLAB has been working on an attractive SDR solution, to provide flexibility and handle the processing speeds required of 3G radio receivers . The approach is based on SDR architectures that partition radio receiver processing into two core technologies (field programmable gate arrays and D SP devices). We present a summary of the SDR work at WINLAB that is based o n using this mixed signal processing approach for implementation of nonline ar interference cancellation and linear multi-user detection algorithms.