Performance of Advanced Discrete-Time RAKE Receivers

In this paper, we investigate the performance of several advanced discrete-time RAKE receivers under the effect of channel statistics estimation errors. The name of the first receiver is the decorrelating discrete-time RAKE receiver (D-DTR), which improves the performance in the presence of channel estimation errors in diffuse channels. The second receiver is the discrete-time version of the generalized RAKE (G-DTR) receiver. The G-DTR has been proposed for correlated interference mitigation. The last system is the generalized decorrelating discrete-time RAKE receiver (GD-DTR), which combines the benefits of the D-DTR and the G-DTR. In the literature, it is shown that the D-DTR is sensitive to the estimation of the channel covariance matrix. In this work, we reduced this sensitivity and according to our results in worst case scenario the performance of the D-DTR is equal to a conventional discrete-time RAKE receiver (C-DTR). For the case of the GD-DTR, we introduce a very simple method for the estimation of the noise plus interference statistics and we modify the channel statistics estimation method of the D-DTR to be valid for the GD-DTR. Our simulations show that the GD-DTR needs an estimation quality above some threshold for a performance gain compared to the C-DTR