Conference Paper

A genetic algorithm based finger selection scheme for UWB MMSE rake receivers

Department of Electrical Engineering, Princeton University, Princeton, New Jersey, United States
DOI: 10.1109/ICU.2005.1569977 Conference: Ultra-Wideband, 2005. ICU 2005. 2005 IEEE International Conference on
Source: IEEE Xplore


Due to a large number of multipath components in a typical ultra wideband (UWB) system, selective rake (SRake) receivers, which combine energy from a subset of multipath components, are commonly employed. In order to optimize system performance, an optimal selection of multipath components to be employed at fingers of an SRake receiver needs to be considered. In this paper, this finger selection problem is investigated for a minimum mean square error (MMSE) UWB SRake receiver. Since the optimal solution is NP hard, a genetic algorithm (GA) based iterative scheme is proposed, which can achieve near-optimal performance after a reasonable number of iterations. Simulation results are presented to compare the performance of the proposed finger selection algorithm with those of the conventional and optimal schemes.

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Available from: Hisashi Kobayashi, Apr 25, 2014
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    • "To overcome the drawbacks of the full-rank algorithms in UWB communications, reduced-rank schemes have recently been considered. A reduced-order finger selection linear minimum mean square error (MMSE) receiver with RAKE-based structures have been proposed in [16], which requires the knowledge of the channel and the noise variance. Solutions for reduced-rank channel estimation and synchronization in singleuser UWB systems have been proposed in [17]. "
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    ABSTRACT: In this paper, we propose a novel low-complexity reduced-rank scheme and consider its application to linear interference suppression in direct-sequence ultrawideband systems (DS-UWB). First, we investigate a generic reduced-rank scheme that jointly optimizes a projection vector and a reduced-rank filter by using the minimum mean square error (MMSE) criterion. Then, a low-complexity scheme, which are denoted the switched approximation of adaptive basis functions (SAABFs), is proposed. The SAABF scheme is an extension of the generic scheme, in which the complexity reduction is achieved by using a multibranch framework to simplify the structure of the projection vector. Adaptive implementations for the SAABF scheme are developed by using least mean squares (LMS) and recursive least squares (RLS) algorithms. We also develop algorithms for selecting the branch number and the model order of the SAABF scheme. Simulations show that, in the scenarios with severe intersymbol interference (ISI) and multiple-access interference (MAI), the proposed SAABF scheme has fast convergence and remarkable interference suppression performance with low complexity.
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    • "The genetic algorithm (GA) is of much lower computational complexity compared to the MLD approach [5]. GA is a well studied and effective search technique used in lots of work found in [6] and [7]. The effectivenes of an inversion operator in a basic GA, and in a GA using fitness scaling was compared in [8]. "
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    ABSTRACT: We investigate the effects of two different scaling methods and two mutation types on the performance of a genetic algorithm (GA) based equalization approach for direct sequence Ultra-wideband (DS-UWB) wireless communications. Also, we use adaptive generation along with some other parameters to know their effects on the performance in comparison to a previous work, where GA is combined with a RAKE receiver to combat the inter-symbol interference (ISI) due to the frequency selective nature of UWB channels for high data rate transmission. The scaling and mutation methods are combined to give us four different scenarios to compare our results.
    Full-text · Conference Paper · Jan 2010
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    • "GA has also been applied to UWB communications systems in [10] and [11]. In [10], a GAbased iterative finger selection scheme which depends on the direct evaluation of the objective function was proposed. UWB pulse design method was carried out in [11] using the GA optimization. "
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    ABSTRACT: We propose a genetic algorithm (GA) based equalization approach for direct sequence ultra-wideband (DS-UWB) wireless communications, where GA is combined with a RAKE receiver to combat the inter-symbol interference (ISI) due to the frequency selective nature of UWB channels for high data rate transmission. Simulation results show that the proposed GA based structure significantly outperforms the RAKE receiver. It also provides a close bit error rate (BER) performance to the optimal maximum likelihood detection (MLD) approach, while requiring a much lower computational complexity.
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