Type-based receiver for wideband CDMA

Third generation wireless systems plan to use wideband code-division multiple access (CDMA) technologies for their communication schemes. Unlike current standards, such as IS-95, these new systems will transmit both voice and data information at much higher rates than currently offered today. To support these high data rates, the new wideband CDMA systems (WCDMA and cdma2000) will make use of shorter user codes and more aggressive power control schemes. As a consequence, the multiuser interference at the receiver will be strongly non-Gaussian and thus degrade the performance of the standard receiver. To combat this, we present a novel “type-based” receiver which outperforms the current industrial gold standard (RAKE receiver) in most reasonable operational scenarios. This type-based receiver is asymptotically optimal with respect to any form of multiuser interference and any form of background noise, mimics the performance of multiuser detectors without having to know the interfering users´ chip sequences, doesn´t suffer from the “near-far” problem, and matches the computational complexity of the RAKE receiver. These properties make this new receiver ideally suited for both indoor and outdoor CDMA based cellular systems operating in interference limited, multipath environments