Performance of Coherent UWB Rake Receivers using different Channel Estimators

The performance of DS-UWB and TH-UWB for a single-user link is compared for a data rate of 100 Mbps using the newly proposed, realistic UWB channel model from IEEE P802.15. The performance of suboptimal, fractionally spaced (FS), coherent Rake receivers with a pulse matched filter is evaluated with numerical simulations when different channel estimation algorithms, suitable for coherent detection, are used. The FS-Rake receiver is compared with pulse and symbol spaced Rake receivers and an optimal maximum-likelihood detector. Assuming perfect channel estimates, the FS-Rake receiver causes losses of 1 dB compared with the ML detector. For the FSRake receiver, the best evaluated channel estimation algorithm has a fractional loss compared with the perfect estimated channel. Using this algorithm, DS-UWB outperforms TH-UWB with 2 dB when the transmitter-receiver separation is 0 to 4 metre. Since TH-UWB is also more difficult to synchronize, the conclusion is that DS-UWB is more suitable for high-speed indoor links.