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We experimentally demonstrate a 36-Gb/s DMT signal transmission over 50-km SSMF based on a cost-effective 10-GHz DML-based IM/DD system. The data rate is improved by 22% with Volterra filtering.
As a result of population aging, remote electrocardiograph (ECG) monitoring systems have increasingly gained attention. The traditional ECG signal acquisition system has many limitations. This paper presents a high-precision sigma-delta modulator for ECG signal acquisition. The circuit is implemented in a SMIC-EE 0.18 µm process. Simulation results indicate that the signal-to-noise ratios with and...
This article discusses the detection problem of a passive multistatic radar system with a non-cooperative illuminator of opportunity in the presence of compensation errors. Two detectors are used to address this detection problem according to whether the noise powers in the receivers are equal or not. Both of them have a constant false alarm rate with respect to the noise power. Numerical examples...
Energy efficiency (EE) of wireless communications has attracted growing attention in recent years. In this paper, we focus on the EE optimization in cognitive radio networks (CRN) from a perspective of designing MAC frame structure, namely scheduling the sensing-then-transmission time slots. Considering secondary users adopting channel handoff to avoid collisions with primary users, the EE of CRN...
For noncircular signals, optimal widely linear (WL) minimum variance distortionless response (MVDR) beamformer has a powerful performance by exploiting the noncircularity of the received signals. Though, the noncircularity rate can be estimated by the steering vector (SV) of the signal of interest (SOI), the performance degrades as there exist errors in the SOI's SV. This paper introduces a new robust...
In this paper, we examine the channel estimation problem for one-way relay network(OWRN) under time-selective fading channel scenario. Our aim is to estimate the individual channels of each relay hop at the destination with unknown data from source. We utilize the relay's aided estimation function through superimposing pilots at relay, adopt the autoregressive (AR) model to characterize the time-varying...
In this paper, we examine the Bayesian Cramér-Rao lower bounds (BCRBs) for channel estimation in an amplify-and-forward (AF) one-way relay network (OWRN) under time selective flat fading scenario, where the superimposed training is adopted at relay node in order to achieve individual channel estimation. We formulate the nonlinear dynamic state space for individual channels and derive online/offline...
In this paper, the Bayesian Cramér-Rao lower bounds (BCRBs) on dynamic individual channel estimation is examined in an amplify-and-forward (AF) one-way relay network (OWRN) under time selective flat fading channel scenario, where the superimposed training framework is adopted. The target of our work is to formulate the nonlinear dynamic state-space equation for individual channels and derive the online/offline...
We experimentally demonstrate that the digital coherent superposition of optical OFDM subcarrier pairs with Hermitian symmetry can mitigate phase noise, including laser phase noise and self-phase modulation in a nonlinear optical fiber transmission.
An optimal spectrum sensing algorithm is proposed based on the Neyman-Pearson theorem in this paper. The probability of detection is mathematically formulated through analytical discussions. The computational complexity of proposed algorithm is lower than that of the conventional algorithm based on multitaper method with singular value decomposition (MTM-SVD) because SVD is omitted in the proposed...
In this paper, a content-based audio retrieval method is proposed, which can quickly detect and locate similar sound in audio database. We extract a chroma-based audio feature: chromagram, a variation on time-frequency distributions, which represents the spectral energy at each of 12 pitch classes. Compared with traditional feature MFCC (Mel Frequency Cesptral Coefficient), chromagram is better when...
Considering noise interference often exists in audio processing, it is not robust enough to calculate audio similarity by using distance measure directly. In this paper, basing on Renyi's quadratic entropy, a novel scheme for audio similarity measure is proposed. In our work, we extract Mel Frequency Cepstral Coefficients (MFCCs) to represent each audio, and then calculate the similarity based on...
Spectrum sensing is one of the most important technologies for cognitive radio. In order to decrease the effect of low SNR, and increase the reliability spectrum sensing performance, we propose a novel spectrum sensing approach, which collects the distributed collaborative beamforming signals as the test statistic to input the energy detector. In particular, the collaborative beamforming method can...
The differential constant modulus (DCMA) multiuser detection can obtain higher steady-state decorrelating performance than the conventional linear algorithm under high SNR condition similar as the constant modulus algorithm (CMA). Unlike CMA criterion, DCMA has single global minimum which leads to the convergence independent from the amplitudes of received signal. However, the closed-form analysis...
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