UWB spectrally-encoded spread-time CDMA in the presence of multiple gaussian interferences: RAKE receiver and three-level codes

In this paper we study and analyze the performance of the RAKE receiver for a typical ultrawideband (UWB) spectrally-encoded spread-time (ST) CDMA in the presence of multiple Gaussian interference (GI) signals. We demonstrate that by combining useful properties of three-level codes, i.e., codes with values of -1, 0, +1, and RAKE receiver, we can introduce a new strategy in which it can result in superior performance when compared to previous results. In particular, following a discussion on three-level codes we can show that RAKE receiver with optimum multiplicative weights achieves a better performance when compared with simple two-level codes. With the help of an example we show various properties of RAKE receiver as well as three-level codes and relate these properties to a number of simple descriptive parameters of the communication media. Simulation results obtained in this paper indicate the precision with which the analytical results have been obtained in modeling the above system.