In some satellite Internet of Things (IoT) devices with terrain shielding, the qualities of the direct source-destination (S-D) channel are poor, requiring cooperative communications with multi-relays to be employed. ...
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In some satellite Internet of Things (IoT) devices with terrain shielding, the qualities of the direct source-destination (S-D) channel are poor, requiring cooperative communications with multi-relays to be employed. In order to solve error propagation of current decode-and-forward (DF) on such occasions, an efficient polar coded selective decode-and-forward (SDF) cooperation method is proposed with a new decision threshold derived from channel state information (CSI). First, the proposed threshold is derived from the CSI by exploiting the channel gain ratio of optimal relay-destination link (R-D) with source-relay (S-R) link. The above R-D link possesses good channel quality among all links in the system. Second, when the channel gain ratio of certain relay links is larger than the aforementioned decision threshold, the source and all these relays cooperatively send messages together to the destination to accomplish perfect SDF transmission. Otherwise, all relays are frozen and the messages are directly transmitted through the S-D link. If it fails anyway, a retransmission is subsequently tried in the next transmission cycle. In addition, a polar code for fading channels is designed and adaptively adjusted to a proper code rate according to channel quality to attain good bit error rate (BER) performance. Simulation results show that the proposed scheme achieves about 0.9 and 0.5 dB gain at BER of 10-4, respectively, in multi-relay cooperative communications with multi-path fading channels compared with those of non-cooperation and existing polar coded cooperation channels. Therefore, the proposed polar coded SDF (PCSDF) scheme can improve both the BER and the outage probability (OP) performance in multi-relay cooperative systems, making it quite suitable for heterogeneous network applications in cooperative satellite IoT systems involving sixth-generation (6G) communications.
polarization-adjusted convolutional (PAC) codes are a new family of linear block codes that can perform close to the theoretical bounds in the short block-length regime. These codes combine polar coding and convolutio...
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polarization-adjusted convolutional (PAC) codes are a new family of linear block codes that can perform close to the theoretical bounds in the short block-length regime. These codes combine polar coding and convolutional coding. In this study, we show that PAC codes are equivalent to a new class of codes consisting of inner cyclic codes and outer polar- and Reed-Muller-like codes. We leverage the properties of cyclic codes to establish that PAC codes outperform polar- and Reed-Muller-like codes in terms of minimum distance. (c) 2023 Elsevier Inc. All rights reserved.
In signal processing, it is common to employ various transforms for analyzing or compressing real- or complex-valued signals. If the transform is chosen suitably, certain characteristics of the signal, such as spectra...
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In signal processing, it is common to employ various transforms for analyzing or compressing real- or complex-valued signals. If the transform is chosen suitably, certain characteristics of the signal, such as spectral content or sparsity, become readily accessible by looking at the energy distribution among the coordinates of the signal in the transform domain. In contrast, in information-theoretic settings entropy replaces energy as the key parameter of interest;information is processed directly by acting on the entropy through various transforms. Here we follow the information-theoretic approach and focus on the evolution of entropy in the course of butterfly transforms over arbitrary number fields. In particular, we state conditions for entropy polarization-a phenomenon that has been useful in constructing capacity-achieving source and channel codes. We discuss the possibility of using entropy polarization as a useful tool in signal processing applications. (C) 2021 Elsevier Inc. All rights reserved.
The integration of the fifth generation of mobile communications (5G) into the distribution network has the potential to empower Advanced Metering Infrastructure (AMI) and Phasor Measurement Unit (PMU) applications, t...
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The integration of the fifth generation of mobile communications (5G) into the distribution network has the potential to empower Advanced Metering Infrastructure (AMI) and Phasor Measurement Unit (PMU) applications, thus further advancing the concept of Smart Grid (SG). This paper analyzes the compatibility of 5G-NR (New Radio) standard-recommended coding schemes: Low-Density Parity-Check (LDPC) and polar coding with message formats for generalized AMI and PMU communication recommended by standards IEEE Std 1703 and IEEE Std C37.118.2, respectively. Two standard-defined examples of communication sessions have been considered to determine the required 5G-NR transmission channel and associated coding scheme to be used for AMI and PMU-specific messages. The corresponding simulations have been performed following the specifics and boundaries defined by communication standards for 5G, AMI, and PMUs. In the AMI use case, simulation results indicate LDPC code superiority leading to the recommendation to be used for all message formats. PMU use case results reveal the polar code application benefits for command messaging and its potential to be used for data messaging instead of LDPC code, which would require future adjustments of PMU data message format and further research on latency issues. (C) 2021 Elsevier Ltd. All rights reserved.
In this article, a new multidimensional signal processing scheme for a heated-dot magnetic recording (HDMR) system using double-layered bit-patterned media (BPM) is proposed. This proposed signal processing scheme is ...
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In this article, a new multidimensional signal processing scheme for a heated-dot magnetic recording (HDMR) system using double-layered bit-patterned media (BPM) is proposed. This proposed signal processing scheme is capable of simultaneously detecting data sequences recorded on two tracks in each layer sequentially. The effective transmission rate of the HDMR system with two-track simultaneous log-likelihood ratio (LLR) detection and double-layered recording can be increased about four times that of the HDMR system with single-track LLR detection and single-layered recording if the data sequence recorded on each track has the same rate. It is shown that the error rate performance of the HDMR system with two-track simultaneous LLR detection and double-layered recording shows a significant improvement over the HDMR system with single-track LLR detection and single-layered recording by computer simulation.
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