Partial Channel State Information and Intersymbol Interference in Low Complexity UWB PPM Detection

Abstract

We consider an UWB PPM based wireless body area network with an average throughput of about 1 Mbps. For a long battery autonomy a low duty cycle operation of the nodes and thus a high peak data rate is essential. Due to the moderate path loss a peak data rate in excess of 50 Mbps would be feasible within the FCC transmit power constraints. With current low complexity PPM detectors, such as the energy detector, the peak data rate is constrained to much lower values, because they are very sensitive to intersymbol interference (ISI). In this paper we constrain our attention to low complexity detectors for UWB PPM, which utilize an observation window of one symbol duration to generate the decision variables for the subsequent symbol decoder. The key contribution is a family of detectors, which utilize partial channel state information (CSI) to improve the robustness to ISI. Specifically we treat the following cases of partial CSI: (i) no CSI, (ii) average power delay profile (APDP), (iii) instantaneous power delay profile (IPDP). To further improve the performance in presence of ISI, a simple post-detection maximum-likelihood sequence estimator (MLSE) is introduced. Finally performance results are given, that highlight the tradeoff between complexity and performance covered by the proposed detection schemes