Xueyuan Zhao

Learn More
A new communication approach based on massive Multiple Input Multiple Output (MIMO) with Carrier Aggregation (CA), named AMMCA, is proposed to boost the achievable data rate for multimedia traffic in underwater acoustic channels. The system under study is composed of a surface buoy station with many hydrophones and of an underwater static or mobile node(More)
This paper provides a unified view of time-domain and frequency-domain least square (LS) channel estimation in multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) systems. Time-domain and frequency-domain LS channel estimation are formulated under the same framework and their average mean square error (MSE) lower bounds(More)
The energy efficiency of underwater acoustic carrier aggregation in Orthogonal Frequency Division Multiplexing (OFDM) systems is studied and an energy-efficient aggregation bandwidth selection method is proposed. Via simulations it is found that (i) the aggregation bandwidth has an optimal value maximizing the energy efficiency, (ii) this optimal(More)
A low-complexity and low-power all-analog circuit is proposed to perform efficiently Analog Joint Source Channel Coding (AJSCC). The proposed idea is to adopt Voltage Controlled Voltage Source (VCVS) to realize the rectangular-type mapping in AJSCC. The proposal is verified by Spice simulations as well as via breadboard and Printed Circuit Board (PCB)(More)
The performance degradation in convolutionally coded V-BLAST system is analyzed in this paper. Compared with coded linear filtering approach, it is shown that the coded V-BLAST suffers from serious degradation due to the effect of error propagation. Considering the constraint of the system, a performance improvement method is proposed. It adjusts the(More)
Mode selection problem in MIMO-OFDM system is addressed. A general formulation is introduced to decompose the problem into two decoupled sub-problems: modulation and coding scheme (MCS) selection, and space-time processing (STP) optimization, each of which can be tackled more systematically. Mode selection algorithms can then be developed using a channel(More)
Multi-cell interference coordination via Block Diagonalization (BD), which is widely used in LTE-Advanced interference management, has three main drawbacks: (1) limitation on the number of supported co-channel users; (2) performance degradation in Doppler channels with feedback delay and quantization; and (3) high signaling overhead to exchange Channel(More)
A two-step process is developed to synthesize rare earth doped titania nanorods (RE-TiO2 NRs) as photocatalysts for efficient degradation of lignin under simulated sunlight irradiation. In this approach, protonated titanate nanotubes with layered structures were first prepared by a hydrothermal approach, and rare earth metal ions were subsequently bound to(More)