1,721,340 research outputs found
Equalisation of Broadband MIMO Channels by Subband Adaptive Identification and Analytic Inversion
No full textThis paper introduces the subband method of performing adaptive identification and analytic inversion of broadband MIMO channels. It shows that the techniques can potentially lower the computational cost while improving the performance for highly frequency-selective channel with a long impulse response. It covers subband adaptive identification and shows two methods to invert a broadband MIMO channel, the time-domain and frequency-domain methods. Finally results are shown for adaptation MSE, channel-equaliser MSE and BER performance
Cochlear Hearing Loss Detection System Based on Transient Evoked Otoacoustic Emissions
No full textThe aim of this paper is to evaluate the application of the discrete wavelet transform (DWT) and support vector machines (SVM) to transient evoked otoacoustic emissions (TEOAE) in order to achieve a detection of frequency-specific hearing loss (HL).We introduce a system to determine detection rates between groups of persons with normal hearing, high frequency hearing loss, and pantonal hearing loss. The validity and use of our approach is verified on a different patient grou
A Novel Approach to Detect Cochlear Hearing Loss
No full textThe aim of this paper is to evaluate the application of time-frequency (TF) transforms and support vector machines (SVM) to transient evoked otoacoustic emissions (TEOAE) in order to achieve a detection of frequency-specific hearing loss. We introduce a system to determine detection rates between groups of persons with normal hearing, high frequency hearing loss, and pantonal hearing loss. The validity and use of our approach is verified on a different patient group
A Pilot-Assisted Equalisation scheme for the UMTS-TDD Downlink with Partial Loading
No full textIn this paper, we address a pilot-assisted channel equalisation strategy for the partially loaded downlink time-division duplex (TDD) component of the universal mobile telecommunication system (UMTS). The adaptation is performed by minimising a hybrid cost function based on the constant modulus (CM) criterion for all active users and a mean square error (MSE) criterion for both absent users and pilot signals. Computer simulations are used to assess the performance of the equalisation strategy under various partially loaded conditions
An Optimum Linear Frequency-Selective MIMO Equaliser using Time-Domain Analytic Inversion
No full textIn recent years, theoretical and practical investigations have shown that it is possible to realise enormous channel capacities, far in excess of the point-to-point capacity given by the Shannon-Hartley law, if the environment is sufficient multipath. The majority of work to date on this area has assumed flat sub-channels composing the MIMO channel. As the aim of MIMO systems is often to increase the data transmission rate of a communication system, a wideband and hence highly time-dispersive model would be more appropriate. To properly exploit this environment to realise these capacity increases, the MIMO channel must be equalised so that the performance of any system attempting to harness the multipath diversity can do so while maintaining a satisfactory BER performance. Assuming that the response of the MIMO channel is known at the receiver, a method to create a suitable equaliser is to analytically invert the frequency-selective, or time-dispersive, MIMO channel using a time-domain technique described in this paper. The technique calculates the optimum equaliser coefficients in the MMSE sense
Parameterisation of Transient Evoked Otoacoustic Emissions
No full textIn this paper we compare the application of the discrete wavelet transform (DWT) and wavelet packets (WP) to transient evoked otoacoustic emissions (TEOAE) to conduct a differential diagnosis of frequency-specifc hearing loss. By parameterising the TEOAE with WP, we aim to improve the separation of groups with different hearing ability compared to a DWT parameterisation
Parameterisation Comparison for the Detection of Panic Disorder Using Time-Frequency Transforms and Support Vector Machines
No full textIn this paper we compare the effect of the parameterisation on the automatic detection of diseases based on biomedical data. Exemplarily, we study the analysis of event related brain potentials in patients suffering from panic disorder, whereby the data comprises responses to neutral and panic causing stimuli. This data is parameterised by time-frequency (TF) transforms, from which features are selected by a statistical test. The selected features represent the input to a support vector machine classifier yielding a detection rate for the TF parametrised data. This is compared with detection rates obtained for unparameterised time domain dat
A Fast Multi-Level GFSK Matched Filter Receiver
No full textNear optimal reception of a multilevel Gaussian frequency shift keying symbol can be achieved using a matched filter bank (MFB) receiver, which will require M(K+L-1) filters for M modulation levels, a K-symbol observation interval, and a Gaussian filter with an L-symbol support length. This is prohibitive for most applications for the large values of K necessary to ensure best performance. In this paper we present a recursive algorithm that eliminates redundancy in providing the matched filter outputs by use of a smaller set of 1-symbol long intermediate filters, followed by an iterative process to propagate phase gained over K successive single symbol stages. If exemplarily operated in a Bluetooth receiver, the computational cost can be reduced by two orders of magnitude. Additionally we demonstrate that the intermediate filter outputs provide a means to detect carrier frequency and modulation index offsets, which can be corrected by iteratively recomputing the coefficients of the intermediate filter bank
Difference Evaluation Method for Differential Diagnosis of Frequency-Specific Hearing Loss
No full textThis paper looks at differentiating between patients with different hearing ability based on TEOAE; transformation methods used to parametrise the TEOAE data; assessment of the separability between the groups with different hearing ability—receiver operating characteristic; identifying a set of coefficients Copt to optimise the differentiation of the three groups of different hearing ability; results and conclusio
Concurrent Constant Modulus Algorithm and Decision Directed Scheme for Synchronous DS-CDMA Equalisation
No full textIn this paper, we derive a concurrent constant modulus algorithm (CMA) and decision directed (DD) scheme for blind multiuser equalisation, suitable for downlink DS-CDMA systems. Adaptation is performed by concurrently minimising two cost functions based on either a CM criterion or a DD scheme for all active users. Computer simulations are used to assess the performance of the algorithm
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