IEEE Communications Letters

We show how the iterative decoding threshold of tailbiting spatially coupled (SC) low-density parity-check (LDPC) code ensembles can be improved over the binary input additive white Gaussian noise channel by allowing the use of different transmission energies for the codeword bits. We refer to the proposed approach as energy shaping. We focus on the special case where the transmis... View full abstract»

This letter focuses on the metric sorting step for successive cancellation list decoders for polar codes, which play an important role in the overall comparison process. We propose three effective pairwise metric sorting (PMS) methods based on general pairwise sorting. We first describe a full-sorted PMS architecture with fewer comparators than state-of-the-art methods. Second, we present a half-s... View full abstract»

Write-once memory (WOM) is a storage device, where the cells can only be increased when programmed. A WOM code allows the device to be programmed multiple times without decreasing the cell values. This will allow a longer lifetime in, e.g., flash memory, where frequent erasures wear it out. Most WOM codes assume that the previous state is available when encoding a message; however, this is impract... View full abstract»

Although joint source-channel coding (JSCC) based on double protograph low-density parity-check (LDPC) codes has been shown to be an excellent solution for wireless communication, the protograph LDPC code for source coding needs to be optimized to improve the error-floor performance. In this letter, first, it is found that optimized protograph LDPC codes for channel coding are not optimal for sour... View full abstract»

We consider a class of turbo codes with a band structured interleaver, such that the interleaving (and thus deinterleaving) is done within a window. This ensures that the extrinsic information for each symbol is generated from symbols within a window, allowing the processing of large message blocks with a sliding window decoder. This provides flexibility in terms of decoding latency and also makes... View full abstract»

We study the application of a special class of low-density parity-check codes to the wiretap channel. We construct a randomized coding scheme based on serially concatenated low-density generator matrix codes and their duals extending the approach used for convolutional and turbo codes. Furthermore, we propose an efficient iterative decoder for this scheme utilizing a joint iterative message passin... View full abstract»

The interlinked cycle (IC) structure that generalizes cycles and cliques was defined by Thapa, Ong, and Johnson. Interlinked-cycle-cover (ICC) scheme that leverages IC structures in digraphs to construct scalar linear index codes was proposed. A class of infinitely many digraphs, where the proposed scalar linear codes based on ICC scheme are optimal were characterized by Thapa et. al View full abstract»

A Slow HTTP distributed denial of service (DDoS) attack causes a Web server to be unavailable, but it is difficult to detect in a network, because its traffic patterns are similar to those of legitimate clients. In this letter, we propose a network-based Slow HTTP DDoS attack defense method, which is assisted by a software-defined network that can detect and mitigate Slow HTTP DDoS attacks in the ... View full abstract»

This letter proposes a joint pilot and payload power allocation (JPA) scheme to mitigate the error propagation problem for uplink multiple-input multiple-output non-orthogonal multiple access systems. A base station equipped with a maximum ratio combining and successive interference cancellation (MRC-SIC) receiver is adopted for multiuser detection. The average signal-to-interference-plus-noise ra... View full abstract»

In this letter, we consider the capacity results of network error correction coding over a general multicast network, where a malicious error occurs on each edge with a fixed probability $p$ at each transmission. A pair of upper and lower bounds on the capacity are given, which are proved to coincide for a unicast network wit... View full abstract»

In multicast source-routing scheme, packet encodes the generated multicast tree at the header, and can be delivered successfully by checking the encoded tree. Traditional multicast source-routing uses a single Bloom filter (BF) to represent the multicast tree, which incurs high false positive rate and inefficient space utilization. In this letter, we propose two multicast source-routing using mult... View full abstract»

In conventional content delivery networks (CDNs), where the content providers (CPs) are lack of the topology information, it is difficult for them to determine the content caching and pricing scheme. Furthermore, the small CPs cannot maintain their own cache servers as it is costly. To solve these problems, we propose a novel CDN architecture named software-driven CDN (SCDN) by leveraging the bene... View full abstract»

In this letter, we investigate the problem of providing gigabit wireless access with reliable communication in 5G millimeter-wave (mmWave) massive multiple-input multiple-output networks. In contrast to the classical network design based on average metrics, we propose a distributed risk-sensitive reinforcement learning-based framework to jointly optimize the beamwidth and transmit power, while tak... View full abstract»

This letter studies zero-delay joint source–channel coding for transmission of correlated Gaussian sources over a Gaussian interference channel. We propose to adopt a delay-free hybrid digital and analog scheme, which is transmitting the superposition of scaled source and its quantized version after applying scalar quantization to the source at each transmitter. At the corresponding receive... View full abstract»

A 2-stage network is the most compact multistage interconnection network (MIN) for interconnecting small switches to form a large one. For larger networks, the switches in each stage can be replaced with 2-stage networks to reduce crosspoint cost. The 2-stage network preserves only conditional nonblockingness, while a multirate 2-stage network preserves nonblockingness. Multirate MINs have been ex... View full abstract»

Sparse code multiple access (SCMA) is a promising code-based non-orthogonal multiple-access technique that can provide improved spectral efficiency and massive connectivity meeting the requirements of 5G wireless communication systems. We propose a deep learning-aided SCMA (D-SCMA) in which the codebook that minimizes the bit error rate (BER) is adaptively constructed, and a decoding strategy is l... View full abstract»

In this letter, we propose a robust 3-ary modulation for a pulse width modulation (PWM)-based multi-level perpendicular magnetic recording. In the proposed 3-ary modulation, narrow-width pulses are restrained in PWM signal corresponding to resolution of magnetic media. We evaluate a user bit density (UBD) gain in our proposal using a low-density parity-check (LDPC) coded frame error rate performan... View full abstract»

In this letter, we use stochastic optimization to schedule data transmissions in an adaptive optical code division multiple-access (OCDMA) system to maximize transmission rate. We employ Lyapunov drift theory to formulate a general optimization problem for rate-maximized scheduling in which user codes are adaptively assigned such that time-averaged transmission rate is maximized and important syst... View full abstract»

In this letter, we study a multi-user multiple-input single-output (MU-MISO) visible light communication (VLC) system. The linear precoding for pulse amplitude modulation signal is developed with noisy channel state information (CSI). In this method, the precoding is formulated to achieve user fairness with the constraint of the current range of lighting emitting diodes. The precoding design is go... View full abstract»

Visible light communication (VLC) technology is considered to be an attractive solution for future wireless indoor multimedia communication. To reduce the peak-to-average power ratio, single-carrier frequency division multiple access (SC-FDMA) with time domain asymmetrical clipping is applied for the downlink multi-user VLC system. An improved frequency-domain decision feedback equalizer (FD-DFE) ... View full abstract»

Landmarks are widely used to assist localization of mobile users in indoor environments. Learning a priori unknown or imprecise landmark positions through users’ localization processes can in turn improve their localization performance. In this letter, we develop an analytical framework for landmark learning in localization, in which the positions of the landmarks are conti... View full abstract»

In this letter, we study the outage performance of non-orthogonal multiple access (NOMA) with fixed power allocation over Nakagami- ${m}$ fading channels, where the fading parameters of NOMA users are different. In this scenario, new closed-form expressions are derived for the outage behavior of individual users and the system... View full abstract»

Recently, network function virtualization (NFV) has been widely used in 5G innovation. However, with the implementation of NFV, virtualized wireless access point has suffered a significant performance degradation. In this letter, we propose an efficient packet processing scheme (Tuna) to improve the performance of wireless network virtualization. Specifically, we locate management frame into user ... View full abstract»