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Cloud radio access network (CRAN) is a promising candidate for the next-generation wireless communication systems. In CRAN, remote radio heads (RRHs) are deployed to serve users in a target area, which are connected to a central processor (CP) via limited-capacity links termed the fronthaul. In practice, the large amount of information transferred between each RRH and the CP for centralized processing...
Wireless communication systems use adaptive modulation and coding (AMC) as well as hybrid ARQ (HARQ) to mitigate the effects of time-varying and error-prone channels. In this work, we analyze the benefits of combining HARQ and AMC adopting the throughput as a unique performance measure. The analysis of block-fading channels and error-prone decoders allows us to conclude that i) adding HARQ on top...
Partially overlapped channels (POCs) have been studied recently to improve network performance. However, the current OFDM-based 802.11 system is designed for co-channel communication, and does not support communication over POCs. Thus the coordination between POCs imposes a new challenge to WLANs. In this paper, we present DSN (Data Symbol Nulling), a novel communication strategy that leverages the...
In this work, we propose and optimize a new coding strategy designed to enhance the throughput of hybrid ARQ (HARQ) transmissions over i.i.d. block-fading channels where the channel state information (CSI) is unknown at the transmitter. Unlike in the conventional approach, where many blocks are exclusively assigned to carry the HARQ rounds of a single packet, we use a joint coding and the same channel...
This paper considers interference mitigation techniques in the forward link of multibeam satellite systems. In contrast to previous works, either devoted to receiver interference mitigation (e.g. multiuser detection) or transmitter interference mitigation (precoding), this work evaluates the achievable rates of the joint combination of both techniques. On the one hand, precoding cannot properly mitigate...
We propose a new linear physical-layer network coding and information combining scheme for the K-user fading multiple-access relay network (MARN), which consists of K users, one relay and one destination. The relay and the destination are connected via a rate-constraint backhaul link. In the proposed scheme, the K users transmit signals simultaneously. The relay and the destination receive the superimposed...
To improve the performance of noisy automatic speech recognition (ASR), it is effective to prepare multiple ASR systems that can address the large varieties of noise. However, the optimal ASR system is different for each environment and mismatches between training and testing degrade ASR performance. In this situation, the overall system combination of multiple systems is effective; however, the computational...
Low probability of detection (LPD) communication refers to reliable transmission of information that is difficult to detect by an unauthorised adversary. This paper studies LPD communication over parallel Gaussian channels, which are used to model a variety of communication scenarios. First a lower bound on the miss detection probability is derived assuming the adversary employs Neyman-Pearson hypothesis...
We derive the outage probability of a multi-source multi-relay transmission system, where all the links experience κ-μ fading variations. The source-relay links are assumed to be non-orthogonal multiple access channels (MACs). Two transmission schemes are considered for relay-destination transmission, i.e., non-orthogonal maximum ratio transmission (MRT) and orthogonal transmission with joint-decoding...
Long range low power is a family of technologies promising to connect thousands of sensors to the future internet of things. Within this family of possible technology choices, two different branches have emerged: the standards based on spreaded wideband communication and the standards based on narrowband communication, both promising to reach long range connectivity at very low power. More specifically,...
Differential encoded LDPC (DE-LDPC) coded systems with multiple symbol differential detection (MSDD) scheme can avoid good estimation of channel state information and compensate performance degradation of differential detection. In this paper, LDPC codes optimization for the DE-LDPC coded systems with MSDD is studied. Simulation results show that the optimized LDPC codes perform much better than the...
Cyclically-coupled quasi-cyclic LDPC (CC-QC-LDPC) block codes have been shown to achieve outstanding bit error performance with extremely low error floor. In this paper, we propose two new types of CC-QC-LDPC block codes which can achieve a larger girth. We present the error performance of the CC-QC-LDPC codes constructed by the new mechanism. We show that with similar codelengths, the new codes outperform...
The higher order constellation scheme, i.e., 128AP-SK, has been adopted in the latest generation satellite digital video broadcasting (DVB-S2X) standard. It significantly improves the spectral efficiency, but also introduces serious complexity problems in the implementation of the demapper. This paper presents an efficient soft demapper for 128APSK of DVB-S2X based on the concept of decision region...
A novel self-normalized weighted bit-flipping (SNWBF) decoding algorithm for low-density parity-check (LDPC) codes is proposed. Compared to the best known weighted bit-flipping decoding, the SNWBF algorithm converges significantly faster but with little performance penalty. For decoding of LDPC codes, the proposed SNWBF algorithm considers not only the reliability of the neighboring check nodes, but...
The transmission distance of continuous variable QKD (CV QKD) protocol based on Gaussian modulation has been quite limited by the low efficient reconciliation protocol. On the other hand, noiseless linear amplifier (NLA) have greatly enhanced the ability of CV QKD. In this paper, we propose a Gaussian post-selection method simulating NAL in CV QKD, followed by a reconciliation process based on systematic...
Non-orthogonal multiple access (NOMA), which improves spectrum efficiency and system throughput, is one of the promising radio access techniques for 5G. In this paper, NOMA is combined with spatial multiplexing multiple-input multiple-output (MIMO) technology for enhanced spectral efficiency. In multi-stream MIMO signaling, we considered stronger far user's MIMO signal when detecting the near user's...
Spectrum sensing (SS) is the key enabling technology for wideband cognitive radio networks, where two coexisting systems share the same frequency band. The critical task of SS is required to detect spectrum opportunities and to determine if the spectrum allocation meets the quality of service (QoS) requirements of different users. In case of missed detection, collision happens between secondary and...
The compact genetic algorithm cGA is used in this paper to design an efficient soft-decision decoding algorithm, especially for the cyclic codes, because the cGA dramatically reduces the population's size and rapidly converges to the optimal solution compared to classical genetic algorithms. Our main contribution is to exploit the cyclic property of cyclic linear codes to reduce the complexity of...
LDPC code is a powerful error correcting code used in many communication systems. Efficient decoding algorithm and hardware implementation of LDPC code is an important issue. The paper proposes an improved version of the Normalized Min-Sum (NMS) decoding algorithm named “Girth-Aware NMS”. The principle of the GA-NMS is to determine “offline” the optimal normalisation factor of the extrinsic message...
Intracortical brain-machine interfaces (BMIs) aim to provide motor functions via high-performance neural prosthetics to patients with tetraplegia. BMI simulation can be useful in certain circumstances to evaluate functional environments of neuronal conditions, avoiding clinical issues such as infection or tissue damage. In this study, we performed a stimulation study on an intracortical BMI for the...
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