Rake Receiver Fingers Research Articles

Implementation of Seven Finger RAKE Receiver using MRC Technique

The radio receiver that counters the effects of the multipath fading is known as a rake receiver. Rake receiver used to combine the multipath signals by number of ‘sub receivers’ known as ‘fingers’. Rake receiver uses a multipath diversity principle; it rakes the energy from the multipath propagated signal components. This paper gives the review on implementation of MRC (Maximal Ratio Combining) for the seven fingers rake receiver. It gives the same information to receiver as transmitter, it eliminates the multipath fading and the time offset estimation to seven fingers of rake receiver. In the simulation results we observed that both the signals that is input and output signal resembles the same with the help of MRC.

The Performance Evaluation of 802. 15. 3a UWB Channel Model with Different Rake Receiver Fingers of Maximal Ratio Combiner Scheme

In this paper we proposed an analytical method which is used for 802.15.3a UWB channel to find out the effect of rake receiver finger with Maximal ratio combining (MRC) scheme. We used a mathematical model which is derived while considering the receiver is MRC rake receiver. In this receiver we assigned weights to rake receiver finger in such a way to maximize the signal to noise ratio (SNR). With the help of maximal ratio combining (MRC) mathematical model we try to evaluate the performance result with different rake receiver finger.

Bit error rate analysis in IEEE 802.15.3a UWB channels

In this paper, we present a computable bit error rate (BER) expression for the binary signals in the IEEE 802.15.3a ultra-wideband (UWB) channel. In the literature, the impacts of the RAKE receiver's finger numbers and lognormal shadowing on the BER performance have not been reported yet. We propose a characteristic function (CF) based BER formula to overcome the convergence problem of the existing moment generating function (MGF) approach when the BER calculation takes account of the shadowing effect. Simulation results demonstrate that the proposed CF-based computable BER formula can accurately estimate the complete effects of the cluster and ray arrival processes, the lognormal fading as well as shadowing, and the finger numbers at RAKE receivers.

A novel RAKE receiver finger number decision rule

RAKE receiver is widely used in wideband code division multiple access (W-CDMA) systems to combat multipath fading. For maximal ratio combining, theoretically, the signal-to-noise ratio (SINR) increases as the number of RAKE receiver fingers increases. However, channel estimation can never be perfect in practice. If we increase improper fingers, the SINR of the added fingers decreases and the channel estimation error increases, which degrades the detection performance. An analytical decision rule for choosing the proper number of RAKE receiver fingers is derived. The decision rule is very simple and can be shown to have optimal SINR for the RAKE receiver.

Effects of carrier tracking in RAKE reception of wide-band DSSS in Rician fading

An analysis is given of the effect of phase tracking error in the fingers of a coherent RAKE receiver. Results for constant and exponentially decaying power delay profiles indicate that, for sufficiently low tracking loop signal-to-noise ratio, a point is eventually reached where performance does not improve with the use of an increased number of fingers. This suggests that the expected performance improvement due to finer multipath resolution in the very wideband personal communications systems anticipated for third generation will be negated by parameter estimation error unless special care is taken to minimize these errors, such as jointly optimum detection and estimation procedures.

Impact of spreading bandwidth on RAKE reception in dense multipath channels

Spread spectrum (SS) multiple access techniques have been proposed for third generation broadband wireless access. We develop an analytical framework to quantify the effects of spreading bandwidth on SS systems operating in dense multipath environments in terms of the receiver performance, receiver complexity, and multipath channel parameters. In particular, we consider wide-sense stationary uncorrelated scattering (WSSUS) Gaussian channels with frequency-selective fading. The focus of the paper is to characterize the combined signal of the RAKE receiver fingers tracking the strongest multipath components. Closed form expressions for the mean and the variance of the total RAKE receiver output signal-to-noise ratio (SNR) are derived in terms of the number of RAKE fingers, spreading bandwidth, and multipath spread of the channel. The proposed problem is made analytically tractable by transforming the physical RAKE paths into the virtual path domain. A representative result indicates that for SS systems with 5 MHz signal bandwidth operating in a channel with constant power delay profile having 5 /spl mu/s spread, the average SNR gain from increasing the number of RAKE fingers from one to three is 3.8 dB and from three to five is 1.5 dB. Furthermore, the reduction in the variation of SNR is 1.1 dB and 0.4 dB for the same increments in the number of fingers.