Amplitude Modulation

14,000,000 Leading Edge Experts on the ideXlab platform

Scan Science and Technology

Contact Leading Edge Experts & Companies

Scan Science and Technology

Contact Leading Edge Experts & Companies

The Experts below are selected from a list of 79656 Experts worldwide ranked by ideXlab platform

Sung-joon Park - One of the best experts on this subject based on the ideXlab platform.

  • ICC - Jointly optimized quadrature Amplitude Modulation
    2016 IEEE International Conference on Communications (ICC), 2016
    Co-Authors: Sung-joon Park
    Abstract:

    Quadrature Amplitude Modulation has been widely used for high-speed data transmission in modern digital communication systems. In this work, a generalized quadrature Amplitude Modulation which relaxes the constraint of square lattice is suggested to improve the joint performance of Modulation and coding. Bitwise log-likelihood ratios and input signal-to-noise ratios for decoder are analyzed and the strategy minimizing the probability of decoding error is investigated. The analytical argument is consolidated by conducting simulations with a turbo code. According to results, the proposed scheme presents a power gain which depends on Es/N0 and a Modulation order.

  • performance analysis of triangular quadrature Amplitude Modulation in awgn channel
    IEEE Communications Letters, 2012
    Co-Authors: Sung-joon Park
    Abstract:

    Recently, the triangular quadrature Amplitude Modulation (TQAM) whose signal points are regularly distributed at the vertexes of contiguous equilateral triangles was proposed. In this paper, we derive the general formula calculating the average energy per symbol of the TQAM and find out that the asymptotic power gain of the TQAM over the well-known square quadrature Amplitude Modulation (SQAM) is 0.5799 dB. We also analyze the symbol error rate (SER) and the bit error rate (BER) of the TQAM and compare them with the error performances obtained through computer simulation. Analytical and simulation results coincide at a wide range of signal to noise power ratio (SNR). The power gain increases gradually and approaches the asymptotic value as Modulation order increases and target error rate decreases.

  • triangular quadrature Amplitude Modulation
    IEEE Communications Letters, 2007
    Co-Authors: Sung-joon Park
    Abstract:

    The square quadrature Amplitude Modulation (QAM) has been widely used for decades. Though it is not optimum in the sense of power efficiency, simple detection makes it in use for numerous digital communication systems deploying high-order Modulation. In this paper, we propose new signal sets which make an effective use of limited power resource. We also suggest simple detection methods for the proposed signal sets to be meaningful from a point of view of implementation. The newly proposed constellations can provide advantages of 0.46 dB and 0.55 dB in signal-to-noise ratio over the square QAM in 16-ary and 64-ary signal sets while keeping low complexity for detection

  • PIMRC - Bit Mapping of Triangular Quadrature Amplitude Modulation
    2007 IEEE 18th International Symposium on Personal Indoor and Mobile Radio Communications, 2007
    Co-Authors: Sung-joon Park
    Abstract:

    The triangular quadrature Amplitude Modulation (TQAM) is a newly designed signal set which has a power gain over the widely used square quadrature Amplitude Modulation (SQAM) and maintains low detection complexity. In this paper, we propose an optimum bit mapping for the TQAM minimizing bit errors. We also suggest a lower bound of Gray coding penalty which can be used as a measure of suboptimum bit mapping. The performance of the proposed bit mapping is shown by approximate analysis and simulation.

Lu Trong Khiem Nguyen - One of the best experts on this subject based on the ideXlab platform.

Gary J Rose - One of the best experts on this subject based on the ideXlab platform.

  • interval integration underlies Amplitude Modulation band suppression selectivity in the anuran midbrain
    Journal of Comparative Physiology A-neuroethology Sensory Neural and Behavioral Physiology, 2003
    Co-Authors: Christofer J Edwards, Gary J Rose
    Abstract:

    We examined the mechanisms that underlie ‘band-suppression’ Amplitude Modulation selectivity in the auditory midbrain of anurans. Band-suppression neurons respond well to low (5–10 Hz) and high (>70 Hz) rates of sinusoidal Amplitude Modulation, but poorly, if at all, to intermediate rates. The effectiveness of slow rates of sinusoidal Amplitude Modulation is due to the long duration of individual ‘pulses’; short-duration pulses (<10 ms) failed to elicit spikes when presented at 5–10 pulses s−1. Each unit responded only after a threshold number of pulses (median=3, range=2–5) were delivered at an optimal rate. The salient stimulus feature was the number of consecutive interpulse intervals that were within a cell-specific tolerance. This interval-integrating process could be reset by a single long interval, even if preceded by a suprathreshold number of intervals. These findings indicate that band-suppression units are a subset of interval-integrating neurons. Band-suppression neurons differed from band-pass interval-integrating cells in having lower interval-number thresholds and broader interval tolerance. We suggest that these properties increase the probability of a postsynaptic spike, given a particular temporal pattern of afferent action potentials in response to long-duration pulses, i.e., predispose them to respond to slow rates of Amplitude Modulation. Modeling evidence is provided that supports this conclusion.

T A Gulliver - One of the best experts on this subject based on the ideXlab platform.

Radan Slavík - One of the best experts on this subject based on the ideXlab platform.

  • Modulator-free quadrature Amplitude Modulation signal synthesis
    Nature Communications, 2014
    Co-Authors: Joseph Kakande, Brian Kelly, John O’carroll, Richard Phelan, David J. Richardson, Radan Slavík
    Abstract:

    The ability to generate high-speed on–off-keyed telecommunication signals by directly modulating a semiconductor laser’s drive current was one of the most exciting prospective applications of the nascent field of laser technology throughout the 1960s. Three decades of progress led to the commercialization of 2.5 Gbit s^−1-per-channel submarine fibre optic systems that drove the growth of the internet as a global phenomenon. However, the detrimental frequency chirp associated with direct Modulation forced industry to use external electro-optic modulators to deliver the next generation of on–off-keyed 10 Gbit s^−1 systems and is absolutely prohibitive for today’s (>)100 Gbit s^−1 coherent systems, which use complex Modulation formats (for example, quadrature Amplitude Modulation). Here we use optical injection locking of directly modulated semiconductor lasers to generate complex Modulation format signals showing distinct advantages over current and other currently researched solutions. Quadrature Amplitude Modulation signalling is currently enabling rapid data transfer capacity growth, but it still has associated drawbacks. Here, Liu et al. use optical injection locking to generate complex Modulation format signals with reduced consumption, small footprint and easy integration.