2DPSK Signal Detection Based on Cascaded Stochastic Resonance

In the case of poor channel environment, the detection and reception of digital signal often appear errors. In view of this situation, by reducing the error rate of coherent reception of 2D PSK signals, we propose a new method based on the detection efficiency and improved cascaded stochastic resonance theory.A cascaded bistable stochastic resonance model was established by using stochastic resonance theory. The nonlinear receiver was used to receive 2DPSK signal under small signal-to-noise ratio (SNR). The experimental results show that the spectrum peak of the output signal of cascade stochastic resonance system is 5.70 times that of the traditional model. The output error rate of cascaded nonlinear system model can be reduced by 92.31% compared to the traditional model when the input signal to noise ratio is -7dB. Consequently, the output signal of the system is more likely to be detected and the accuracy can be greatly improved

Optimum symbol-by-symbol detection of uncoded digital data over the Gaussian channel with unknown carrier phase

10.1109/26.310614IEEE Transactions on Communications4282543-2552IECM

Embedding Power Line Communication in Photovoltaic Optimizer by Modulating Data in Power Control Loop

In Photovoltaic (PV) system, dc-dc power optimizer (DCPO) is an option to maximize output power. At the same time, data links among DCPOs are often required for system monitoring and controlling. This paper proposes a novel power line communication (PLC) method for the DCPOs, in which the data of a DCPO is modulated into the control loop of power converter, and then transmitted through the series-connected dc power line to other DCPOs. In the process of communication, differential phase shift keying (DPSK) modulation and discrete Fourier transformation (DFT) demodulation are employed. To analyze the quality of communication, the communication model of the system is built, based on small-signal model. Furthermore, the noises of the system, including switching, maximum power point tracking (MPPT) and additive white Gaussian noise (AWGN), are discussed and measured to evaluate the signal-to-noise ratio (SNR). At last, an experimental system including 6 DCPOs is established and tested, which verifies the feasibility and effectiveness of the proposed method

Bayesian Modeling For Dealing With Uncertainty In Cognitive Radios

Wireless communication systems can be affected by several factors, including propagation losses, co-channel interference, and multipath fading. Uncertainty affects all of these factors making it even more difficult to model these systems. This dissertation proposes the use of probabilistic graphical models (PGM), such as Bayesian Networks and Influence Diagrams, as the core for reasoning and decision making in adaptive radios operating under uncertainty. PGM constitute a tool to understand and model complex relations among random variables. This dissertation explains how to build effective communication models that perform its functions under uncertainty. In addition, this work also presents a spectrum sensing technique based on the autocorrelation of samples to estimate the utilization level of wireless channels

Modulation Schemes and Connectivity in Wireless Underground Channel

In this chapter, a thorough treatment of the modulation schemes for UG Wireless is presented. The effects of soil texture and water content on the capacity of multi-carrier modulation in WUC are discussed. The multi-carrier capacity model results are analyzed. Moreover, the underground MIMO design for underground communications is explained thoroughly. An analysis of medium access in wireless underground is done as well. Furthermore, the soil properties are considered for cross-layer communications of UG wireless. The performance analysis of traditional modulation schemes is also considered. The soil moisture-based modulation approach is also explored in this chapter. The connectivity and diversity reception approaches are discussed for wireless underground communications. The connectivity and interference models are studied for Ad-Hoc and Hybrid Networks. The topology control mechanisms for maintaining network connectivity are explored for maximizing network capacity under the physical models (e.g., the protocol interference model and physical interference model). Moreover, the underground diversity is examined for 3W-Rake receiver and coherent detection along with experimental evaluation and comprehensive analysis of performance of equalization techniques

RECEIVER DESIGN AND PERFORMANCE ANALYSIS FOR COMMUNICATION CHANNELS WITH CARRIER PHASE NOISE AND FADING

Ph.DDOCTOR OF PHILOSOPH