Enhancement of a Three Combining Techniques Rake Receiver Using Adaptive Filter of M-Max Partial Update RLS Algorithm for DS-UWB Systems Rashid A. Fayadh, F. Malek, Hilal A. Fadhil
Enhancement of a Three Combining Techniques Rake Receiver Using Adaptive Filter of M-Max Partial Update RLS Algorithm for DS-UWB Systems 1
Rashid A. Fayadh, 2F. Malek, and 3Hilal A. Fadhil Electrical and Electronic Technical Engineering College, Foundation of Technical Education, Baghdad, Iraq 2 School of Electrical System Engineering, University Malaysia Perlis 3 School of Computer and Communication Engineering, University Malaysia Perlis 1
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Abstract Since ultra wideband (UWB) communication systems operate with short pulses and high data rates, the effect of noises and channel fading appeared upon receipt. The rake receiver scheme is used to collect the copies of the time-shifted original signal to make multi-path signals that are separately correlated by correlators. In line of sight (LOS) and non-line of sight (NLOS) propagation indoor environments and according to channel models proposed by IEEE 802.15.4a, M-max adaptive rake receiver (ARR) was proposed with three rake receiver-combining techniques, i.e., maximal ratio combining (MRC), equal gain combining (EGC), and selective combining (SC) that were simulated to capture the fingers output signal energy with perfect channel estimation. A matched filter for the UWB impulse radio was connected to maximize the desired signal over the noises. To minimize the mean squared error (MSE), an adaptive filter using a M-max partial update recursive least squares (RLS) algorithm was used to update the coefficients (tap weights) of the combiner at the decay states to keep the signal-to-noise ratio (SNR) at its optimal values. The proposed rake receiver had the good performance under the RLS proper parameters for the four channel models and three combining techniques. The MRC technique plays a more significant role in reducing the bit error rate (BER).
Keywords: Adaptive matched filter, DS-UWB rake-receiver combining techniques, RLS and SNR. 1. Introduction The need for wireless, short-range (
