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We propose an accurate laser linewidth estimation technique based on the decision-aided maximum likelihood carrier phase estimator (DA-ML). Its performance is verified in M-ary quadrature amplitude modulation (MQAM) within a wide range of the laser linewidths and SNR values.
Sparse unmixing is based on the assumption that each mixed pixel in the hyperspectral image can be expressed in the form of linear combinations of a number of pure spectral signatures that are known in advance. Despite the success of sparse unmixing based on the L0 or L1 regularizer, the limitation of this approach on its computational complexity or sparsity affects the efficiency and accuracy. In...
Sparse unmixing is based on the assumption that each mixed pixel in the hyperspectral image can be expressed in the form of linear combination of a number of pure spectral signatures that are known in advance. Despite the success of sparse unmixing based on the L0 or L1 regularizer, the limitation of these approach focuses on analyzing the hyperspectral data without incorporating spatial structure...
As the size of CMOS devices continues to scale down, the reliability of circuits becomes one of main challenges in low supply voltage designs. Markov Random Field (MRF) circuits, a probabilistic-based approach, can achieve higher noise immunity compared to traditional designs under conditions of ultra-low supply voltage and low threshold voltage. However, the basic MRF elements have complex structures...
To suppress co-channel interference and achieve good system performance in a Multi-User Multiple Input Multiple Output (MU-MIMO) downlink network, we introduce a novel Interference Alignment (IA) receive matrix design methodology along with a low complexity iterative coordinated beamforming scheme. The introduced scheme takes into account the codebook-based feedback for LTE/LTE-Advanced systems. In...
Feedback structure is an efficient topology for noise-reducing in analog circuit while the cyclic circuit has been widely used in digital circuit only to establish sequential circuits due to its data-keeping property. The Markov Random Field (MRF) based circuit is proposed with feedback structure from the point of energy, which has high noise-immune property in ultra-low supply voltage. However the...
We demonstrated the generation of Nyquist pulses using a dual parallel Mach-Zehnder modulator. 10 GHz to 40 GHz Nyquist pulses with timing-jitter below 258 fs and signal-to-noise ratio more than 30 dB are experimentally generated.
Adaptive blind MIMO equalization algorithm adopting decision feedback recurrent neural network(DFRNN) is proposed and investigated in 4 × 56 Gbit/s MDM-QPSK system. The required-data-length of DFRNN is 1/3 of that in CMA with similar performance.
High frequency pulse injection is part of many diagnostics techniques, e.g. cable fault location. An injected pulse along an underground power cable will reflect at an impedance impurity, for instance a cable joint. These joints can be identified based on pulse reflections only if sufficiently high-frequency components can be detected. Signals with higher frequency components can provide more accurate...
The impact of outdated channel state information (CSI) on the capacity of amplify-and-forward (AF) partial relay selection systems is studied in this paper. The closed-form expressions for the distribution of received signal-to-noise ratio (SNR) in a multi-relay cooperative communications system is first derived, with independent and identically distributed (i.i.d.) Rayleigh fading channels being...
The impact of an imperfect channel estimation on the amplify-and-forward (AF) mode cooperative communications systems is studied, with some important factors, including the probability characteristic of the secondary user's end-to-end signal-to-noise ratio (SNR), the outage probability, the symbol error probability (SEP) and the lower bound on the capacity, etc, being analyzed. As compared to the...
IEEE 802.11 WLAN network standard provides a multi-rate physical layer support, however, did not provide the appropriate MAC layer multi-rate approach. This paper studies the IEEE 802.11 wireless LANs in the rate adaptation scheme. On this basis, and made EMAC agreement, EMAC using the basic rate to send the MAC header, and the confirmation frame to carry the channel information, so it can respond...
Coordinated Multi-Point transmission (CoMP) has been recognized as one of the most promising technologies in the 4th generation (4G) cellular systems. It can significantly increase the spectral efficiency by combining the data from different eNBs. However, the benefits come at the cost of the increased feedback overhead. In the downlink frequency division duplex (FDD) systems, UEs need to feedback...
We demonstrate a method to realize arbitrary repetition-rate multiplication of 40 GHz optical pulses based on optical spectrum manipulation. The generated 80–320 GHz pulses can well maintain the original pulse shape with uniform amplitude and improved SNR.
We propose a symbol-by-symbol (SBS) detector for Gaussian minimum shift keying (GMSK) signals in body area networks (BAN). Our detector exploits the orthogonality between adjacent GMSK-modulated symbols. By dividing the received signals into inphase-/quadrature-channels and odd-/even-streams, the strongest inter-symbol interference (ISI) from the adjacent symbols is removed. A whitened matched filter...
ETC (Electronic Tolling Collection) systems develop rapidly in China in order to relieve the traffic congestion. As the key component of the ETC system, the design of the Radio Frequency (RF) transceiver is usually a tedious and experienced based work due to its high non-linearity. An automatic system level optimization method based on Memetic algorithm (MA) is proposed in this paper. A fitness function...
A feedforward carrier phase estimation algorithm using a modified QPSK partition approach followed by maximum-likelihood (ML) detection is proposed. Results demonstrate complexity reduction by more than a factor of 2 compared with other techniques.
In this study, an enhanced chip-level linear equalizer is proposed for multiple-input multiple-out (MIMO) multi-code code-division multiple access (CDMA) systems in space-time transmit diversity (STTD) mode. By retaining inter-antenna interference (IAI) within the equalized signal in an optimized manner, the signal-to-noise ratio (SNR) of the STTD combiner output is maximized. Substantial performance...
We consider phase-based estimators for chirp parameters due to their high computational efficiency for implementation. Their performances can approach the Cram\'{e}r-Rao lower bound for high signal-to-noise ratio (SNR). One challenge for the phase-based estimators is the performance loss at low SNR because the reliability of phase unwrapping and the accuracy of the phase noise model decrease seriously...
This paper aims at designing a new effective signaling mechanism for relay coordination in LTE-Advanced. Under the new signaling mechanism, the need of synchronization among multiple relays is eliminated, thus it owns advantages of practicality and high spectral efficiency. Also, considering the characteristic of access and backhaul link in LTE-A, the outage capacity and bit error rate for ODAF and...
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