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Visible light communication networks are currently constrained in range by the divergent source characteristics of the light emmiting diode (LED) and in achievable rate by the modulation bandwidth of the LED transmitter; however, as device advancements improve the limitation on rate becomes inter-symbol interference (ISI). The key contributor to ISI is the non-uniform time of arrival (TOA) of all...
For portable deep space communications applications where low power is a key requirement At the receiver, non coherent FSK quadrature detectors is suitable that enable to develop novel design and digitally implemented as VLSI circuits An important consideration in an FSK low power receiver is whether to use coherent detection or non coherent detection. This question arises because the carrier phase,...
In this paper, an energy efficient adaptive modulation scheme is proposed for a wireless cognitive radio ad hoc network, where each node is equipped with cognitive radio and the network is an OFDMA system operating on time slots. In each slot, the users with new traffic demand will sense the spectrum and locate the available subcarrier set. Then they choose subcarriers with favorable channel condition...
In this paper, we develop an approach toward joint source-channel coding (JSCC) for JPEG compressed image transmission. First, a data partition (DP) technique is employed to divide the JPEG bitstream into three groups, namely, Huffman codes, DC coefficients and AC coefficients. Second, we combine the rate-compatible punctured convolutional (RCPC) codes to protect the coded data according to channel...
In this paper, we propose a robust STBC transmission scheme to combat the timing synchronization errors over frequency-selective multiple-access channels. First, the equivalent channel model in the presence of timing synchronization errors is derived and we find that the synchronization errors result in an equivalent channel model with larger number of correlated channel taps. Based on this correlated...
Three applications in wireless networks where model-free stochastic learning is applicable, are discussed. The learning based optimization problems are formulated and simulation results are presented. Some open issues are also discussed.
We designed and built a novel all-optical re-timing, re-amplifying, and re-shaping (3R) regeneration system based on terahertz optical asymmetric demultiplexers (TOADs) developed in our laboratory. The system is capable of parallel processing multiple wavelengths, a feature which will significantly improve the scalability of current wavelength division multiplexing (WDM) networks. Performance against...
Correlative minimum shift keying (MSK), a second order polynomial modulation scheme known as tamed frequency modulation (TFM), is a constant envelope type of modulation with a perfect peak to average power ratio (PAPR), besides the property of low out of band power. We apply the linearized TFM to the single carrier transmission with frequency domain equalization (SC/FDE) concept. We then obtain a...
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