Low Complexity PN Code Acquisition with Tree Search in Wideband CDMA Multipath Channels

In this paper, we propose a novel matchedfilter-type parallel code acquisition scheme to detect uplink short-code wideband CDMA multipath signals. A treestructured parallel adaptive network of RAKE fingers is created for all possible delay shifts and users. Employing a sequential detection scheme, only viable fingers are used to generate the output decision statistics. Monte Carlo computer simulation and numerical calculations have been carried out to study the performance of the algorithm in single-path and multipath channels corrupted with co-channel interference (CCI) and additive white Gaussian noise (AWGN). Both simulation and numerical calculations demonstrate that the proposed algorithm can, at the expense of signal combining loss, significantly reduce the computation complexity and latency of the receiver. Additional signal combining loss is also quantified when the channel estimation error from weighted multislot averaging (WMSA) is taken into account.