Simplified Soft Demapping Algorithm for Gray-APSK

Chen, Pan; Huang, Jiachen; Peng, Kewu; Fan, Liwen

doi:10.1109/wicom.2012.6478674

Cited by 3 publications

(1 citation statement)

References 4 publications

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“…However, these techniques are specific to the constellations and the given bit to symbol mapping. Another important subfamily is the so called product-APSK (or star shape APSK), for which low complexity detection (LCD) has been studied by several authors [14]- [18]. The main drawback of the product-APSK constellations is their inferior performance with respect to the optimized APSK constellations, mainly because number of points are fixed and constant over each ring.…”

Section: Introductionmentioning

confidence: 99%

On Low Complexity Detection for QAM Isomorphic Constellations

Kayhan

2017

GLOBECOM 2017 - 2017 IEEE Global Communications Conference

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Despite of the known gap from the Shannon's capacity, several standards are still employing QAM or star shape constellations, mainly due to the existing low complexity detectors. In this paper, we investigate the low complexity detection for a family of QAM isomorphic constellations. These constellations are known to perform very close to the peak-power limited capacity, outperforming the DVB-S2X standard constellations. The proposed strategy is to first remap the received signals to the QAM constellation using the existing isomorphism and then break the log likelihood ratio computations to two one dimensional PAM constellations. Gains larger than 0.6 dB with respect to QAM can be obtained over the peak power limited channels without any increase in detection complexity. Our scheme also provides a systematic way to design constellations with low complexity one dimensional detectors. Several open problems are discussed at the end of the paper. Index Termsnon-uniform APSK constellations, high order modulations, soft demapping, detection complexity I. INTRODUCTIONHigh order constellations with up to 256 signals have been adopted in new satellite communication standards such as digital video broadcasting (DVB-S2X) [1], in view of the growing demand for spectral efficiency. Given the fact that the traffic demand for satellite broadband is expected to grow six-fold by 2020 [2], and the continuous need for higher data rates in satellite communications, even larger constellations may be needed in near future.The receiver's computational complexity is one of the main concerns in any high throughput communication systems. On one hand, to increase the spectral efficiency one needs to employ high order constellations. On the other hand, the detection computational complexity grows as a function of constellation size and dimension. Indeed, despite the known gap from the Shannon capacity, quadrature amplitude modulation (QAM) constellations are still widely used in some standards (see for example [3]) due to the existing low complexity and simple detector. In this paper, we focus on bit-interleaved coding and modulation (BICM) scheme [4]. In such systems, the log-likelihood ratio (LLR) computations are the receiver's computational bottleneck, specially for large constellations.

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Section: Introductionmentioning

confidence: 99%

On Low Complexity Detection for QAM Isomorphic Constellations

Kayhan

2017

GLOBECOM 2017 - 2017 IEEE Global Communications Conference

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Simplified universal soft demapper for gray-mapped constellation

Chen

Peng

Yang

2015

2015 International Wireless Communications and Mobile Computing Conference (IWCMC)

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Polar Codes and a M-ary Modulation-Based OFDM-PLC System

Wang

Cao

2023

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Power Line Communication (PLC) serves as a medium for communication over power lines, utilizing the existing power grid for information transmission. It offers a low-cost, highly scalable signal transmission method and has the potential to become the preferred technology for providing broadband in smart homes, offices, and smart grids. However, noise in the power line channel, especially impulse noise, seriously affects the communication quality of PLC. In this paper, we establish an OFDM-PLC system with higher-order modulation and polar codes. The higher-order QAM or APSK modulation technique is employed to increase the signal transmission rate and the system performance is analyzed. To combat the impulse noise in the PLC channel, we first model it using a superposition of multi-damping sinusoidal functions and then introduce the polar coding scheme to suppress the impulse noise in the system, thereby improving the transmission reliability. Simulation results verify that the proposed polar coding scheme based on the OFDM-PLC system can improve the Bit Error Rate (BER) performance of PLC channel transmission under impulse interference.

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Simplified Soft Demapping Algorithm for Gray-APSK

Cited by 3 publications

References 4 publications

On Low Complexity Detection for QAM Isomorphic Constellations

On Low Complexity Detection for QAM Isomorphic Constellations

Simplified universal soft demapper for gray-mapped constellation

Polar Codes and a M-ary Modulation-Based OFDM-PLC System

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