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The problem of synchronization in non-contiguous OFDM (NC-OFDM) in the presence of other in-band systems is addressed by means of a comparison between time-and frequency-based signal processing approaches. The filterbank multicarrier scheme with its spectral-efficient offset-QAM (OQAM) OFDM implementation is thereby a good choice for an NC-OFDM system design due to its well-localized spectral signal...
This paper presents a robust radio access technology (RAT) classification framework for acquiring comprehensive knowledge on multiple types of coexisting wireless systems. It is built upon the combination of a group of RAT-specific feature metrics using maximum likelihood estimation (MIE) based decision rules. The classification scheme is enhanced by our proposed dimension cancellation (DIC) method...
To monitor performance in athletic training it is of great importance to detect and extract significant movement features. We analyzed the utility of randomly modulated periodicity and sum signal-to-modulation-noise-ratio (SMNR) for the evaluation of the foot-rest force (FRF), which is a key parameter in rowing. The foot-rest force of elite and novice athletes was recorded with an indoor rower and...
In this work the design of a frequency-domain synchronization and channel estimation scheme for OQAM-OFDM systems is presented and evaluated. The need for signal processing schemes for wireless communication systems, that are processed solely in the frequency domain results from the desire to build frequency-agile radios. Driven by the transition from exclusive spectrum resource allocation towards...
In this contribution the influence of different broadband OFDM schemes on the perceptual audio quality of narrowband wireless microphone links is evaluated, since coexistence scenarios of wireless microphones and Orthogonal frequency-division multiplexing (OFDM) based services arise in the TV bands. Therefore, we present different non-contiguous cyclic-prefix (CP-)OFDM and offset quadrature amplitude...
Embedded cyclostationary signature (ECS) was recently developed as a useful tool for facilitating detection, classification, frequency acquisition and spectrum rendezvous for wireless devices or networks. In this paper, we present a novel technique for conveying extended information on ECS in multi-carrier signals. The extended information may include device/network identity, geo-location data and...
In this paper, we study the coexistence issues of LTE systems operating in the TV white spaces. The study includes a proposal for an appropriate system design as well as a discussion on the LTE system's self-configurability to avoid potential interference to other systems when the resource allocation is made flexible. This is evaluated in terms of achievable PHY-layer throughput and block error rates...
This paper presents the BER performance analyses of a virtual MIMO half-duplex relay system on a WiMAX OFDMA network with Alamouti coding. For such a condition where multi-antenna relay is not an option, employing multiple single-antenna relays in the system would be an alternative to still benefit the diversity gain. The impact of increasing the number of relay nodes to the system performance is...
In this paper, we investigate the impact of antenna spatial correlation on the performance of K-user MIMO interference channel, in which interference alignment technique is employed to align all interferences at receivers. In order to improve the sum-rate and BER performances of the system in low SNR regimes the MMSE-based interference alignment algorithm is deployed. This paper considers a multiuser...
This paper presents the BER performance analysis of a MIMO multi-user relay network. A single relay is employed to assist the transmission between the base station and the mobile station at the cell edge of two neighbouring cells. The relay applies the linear precoding technique, namely, block diagonalization and interference alignment to suppress the interference, and afterwards to forward the signal...
This paper considers ultra-wideband (UWB) based localization of mobile users in indoor environment. Because of severe multipath indoor localization still presents a challenging issue and UWB is often considered as technology enabling precise localization. Typically for UWB Time of Flight (TOF) based approaches like Time of Arrival (TOA) or Time Difference of Arrival (TDOA) are applied. Recently also...
The imperfections of practical receivers such as nonwhite noise floor, noise power uncertainty and spurs normally have large influence on the performance and stability of spectrum sensing. However, in most of the literatures about spectrum sensing, part of or all of theses imperfections are ignored and only addictive white Gaussian noise (AWGN) is assumed in many cases. In this paper, two spectrum...
In this contribution, a carrier frequency offset (CFO) estimator for OQAM-OFDM systems based on the conjugate symmetry property of a properly designed synchronization sequence is proposed. It extends the concept of a previously described symbol-timing and phase offset recovery scheme to build a complete time-domain synchronization method. The outcome of numerical evaluations shows that the proposed...
Pop noise caused by plosives generated by talkers, singers and other vocalists has long been a topic of interest to microphone manufacturers. The articulation of speech plosives (oral-stop consonants such as p, t, and k) can severely degrade the quality of a recording or performance. This is especially true for pressure-differential microphones, where not only is the unwanted artifact heard, but also...
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