Design of Pre-Filters for DS-UWB Downlink

Vol. 1 No. 3

Year: 2013

Issue : Jul-Sep

Title : Design of Pre-Filters for DS-UWB Downlink

Author Name : THULASIRAM ATHURU, C.Subhas

Synopsis :

In mobile radio communication environment, transmitted signal might undergo several reflections and local scatterings depending upon various multipaths available in the channel before reaching at the receiver. These scattered signals are subjected to random delay, fluctuations and phase shifts. Multipathseffects are reduced using various diversity schemes including Raking. The Rake signal can be viewed as the sum of the multipath signals with received signal from each path being scaled by a factor related to the strength of that path. The operation is an equivalent operation to the multiplication of the received signal by the time reversed channel impulse response. We consider the Design of ultra-wideband (UWB) systems that enable high data rate communications for short range wireless applications. In particular we propose two pre-equalization filter (PEF) schemes for multiple-input-single-output (MISO) direct-sequence UWB (DS-UWB) system with Pre-Rake and symbol-by-symbol detection. The first scheme minimizes the total transmitted power from the base station to achieving physical layer quality of service (QoS) for different users. In the second scheme, we consider the minimization of a weighed sum of user’s mean-square-error. In order to obtain a computational tractable solution for this scheme the channel duality is considered. Our approach is sufficiently general to include reduced-complexity version of Pre-Rake that employs a limited number of Rake fingers. Our simulation results show that the proposed PEF schemes with Pre-Rake achieve significant performance over Pre-Rake without equalization.

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