IEEE Communications Letters

The existing elastic control planes (ECPs) suffer from the immediacy and the computing overhead issues in software-defined data center networks (SD-DCNs). In this letter, we propose T-DCORAL which is a new ECP to mitigate both issues in SD-DCNs. T-DCORAL accelerates/decelerates the control plane by allocating a virtual CPU to controllers in runtime, whereas the existing ECPs resize the controller ... View full abstract»

Locally repairable codes (LRCs) are a class of codes which can recover from erasures by accessing a small number of erasure-free code symbols. The objective of this letter is to present a generic construction of ${q}$ -ary cyclic LRCs via cyclotomic polynomials over the finite filed ... View full abstract»

Being part of distributed storage systems, locally repairable codes (LRCs) have drawn great attention in the past years. Inspired by a recent construction of optimal LRCs-based on cyclic codes, constacyclic LRCs are studied in this letter. Specifically, a family of optimal constacyclic $(r,\delta)_{q}$ -LRCs with unbounded len... View full abstract»

Polar codes have recently been adopted as a coding scheme for fifth-generation wireless systems, owing to their excellent performance at short code lengths. In this letter, we propose a cyclic redundancy check (CRC)-aided sphere decoding (CA-SD) algorithm to further improve the performance of short polar codes. It provides better performance than the widely used CRC-aided successive cancellation l... View full abstract»

In this letter, we propose high-rate generalized root protograph (GRP) low-density parity-check (LDPC) codes for a nonergodic two-state binary symmetric channel with block interference with and without block fading. In these channels, the proposed GRP LDPC codes have asymptotic and finite-length performance improvement approaching to channel outage probability. View full abstract»

In this letter, an integrated design of joint source-channel coding scheme based on the double protograph low-density parity-check (DP-LDPC) codes is proposed. As degree-2 variable nodes (VNs) structure plays an important role in the performance of both water-fall and error-floor regions, the maximum number of degree-2 VNs for DP-LDPC codes is determined from a global perspective. By comparing dif... View full abstract»

We propose a novel multi-user hybrid precoder design that imitates the bit error rate (BER) performance of a given fully digital precoder by minimizing the Frobenious norm between them. We show that the proposed design equivalently minimizes the chordal distance between the column spaces of the phase-only RF precoder and the given fully digital precoder. The proposed design, in the large antenna r... View full abstract»

We derive post-processing signal-to-noise-plus-interference-ratio (PP-SINR) for minimum mean square error (MMSE) combining in multiple-input multiple-output (MIMO) filter bank multi-carrier (FBMC) systems based on offset quadrature amplitude modulation (OQAM). We show that the PP-SNR, derived by assuming imperfect receive channel state information, accurately characterizes the symbol error rate (S... View full abstract»

This letter presents a more accurate mathematical analysis, with respect to the one performed in Chung et al.’s 2001 paper, of belief-propagation decoding for low-density parity-check (LDPC) codes on memoryless binary input—additive white Gaussian noise channels, when considering a Gaussian approximation (GA) for message densities under density evolution. The recurrent sequence, d... View full abstract»

A block fading point-to-point communication channel is considered, where the channel statistic varies between two possible choices. Assuming the transmitter is unaware of the instantaneous channel gain values and the current channel statistic, a multi-layer coding approach is incorporated where the optimal rate allocation strategy across code layers is devised maximizing the worst case average ach... View full abstract»

In 2011, Tandon and Ulukus gave an outer bound on the capacity region of the two-user Gaussian multiple access channel (MAC) with noisy feedback based on the idea of dependence balance (DB). This outer bound is described using a covariance matrix with three independent parameters. In this letter, we simplify their results and express the DB-based outer bound in a form using only one parameter. Fro... View full abstract»

The study on short-range ultraviolet communication (UVC) channel modeling is often based on prolate-spheroidal coordinate system in the previous studies. In this letter, we propose a single scattering coplanar model based on spherical coordinate system, where the transmitter beam and receiver field of view (FOV) can point arbitrarily under the limitation that the sum of transceiver elevation angle... View full abstract»

The blockchain is a safe, reliable, and innovative mechanism for managing numerous vehicles seeking connectivity. However, following the principles of the blockchain, the number of transactions required to update ledgers poses serious issues for vehicles as these may consume the maximum available energy. To resolve this, an efficient model is presented in this letter, which is capable of handling ... View full abstract»

Generalized space–time–frequency index modulation (GSTFIM) is proposed for conveying extra information with the aid of the space, time, and frequency indices. GSTFIM subsumes the concept of generalized space–time shift keying (GSTSK), which flexibly activates $Q^{\prime }$ out of $Q... View full abstract»

For high-rate peak-limited intensity-modulated optical systems, the two-dimensional time-disjoint signal space (TDSS) is proposed. Based on the TDSS, the optimal hexagonal constellations (OHCs) are proposed analytically under a peak optical power constraint. Both analytical and simulation results show that our proposed OHCs based on the TDSS have the asymptotical peak optical power gain of 0.753 d... View full abstract»

Orthogonal frequency division multiplexing with index modulation (OFDM-IM) is a novel multicarrier scheme, which uses the indices of the active subcarriers to transmit data. The OFDM-IM also inherits the high peak-to-average power ratio (PAPR) problem, which induces in-band distortion and out-of-band radiation when OFDM-IM signal passes through high-power amplifier (HPA). In this letter, dither si... View full abstract»

Adaptive streaming has motivated information-centric network designs to improve end-user quality of experience (QoE). However, their management and evaluation rely either on conventional cache-level metrics that are poor representations of QoE, or consumer-side indicators that are opaque to network services. This letter proposes a measure to bridge the gap between cache performance and consumer Qo... View full abstract»

In this letter, a high fan-out, scalable, and cluster-based optical interconnect (FSCOI) for data center networks is proposed. FSCOI consists of an optical switch and clusters. Compared to OSA, the improved fan-out of FSCOI is achieved by two steps. The first is a coupler for sending that can multiplex the optical signals from all top-of-rack (ToR) switches within a cluster. The second is a wavele... View full abstract»

As the performance requirements and scale of high-performance computing (HPC) systems grow rapidly, systems with such a large number of computing nodes present significant challenges in network architecture design because their peak performance is increasingly limited by communication rather than computation. Moreover, certain HPC application always shows some specific communication patterns, and ... View full abstract»

This letter presents a solution to the problem of universal representation of graphs exemplifying communication network topologies with the help of neural networks. The proposed approach is based on message-passing neural networks. The approach enables us to represent topologies and operational aspects of networks. The usefulness of the solution is illustrated with a case study of... View full abstract»

Time distribution mechanisms favored for use in the smart grid, such as precision time protocol (PTP), were not designed with security in mind, and thus suffer several security vulnerabilities. PTP is vulnerable to fake timestamp attacks through master impersonation and sync message injection. Such an attack will synchronize clocks to a false time reference. In this letter, we consider an IEC 6185... View full abstract»

Blockchain systems store transaction data in the form of a distributed ledger where each peer is to maintain an identical copy. Blockchain systems resemble repetition codes, incurring high storage cost. Recently, distributed storage blockchain (DSB) systems have been proposed to improve storage efficiency by incorporating secret sharing, private key encryption, and information dispersal algorithms... View full abstract»

This letter presents a new cooperative jamming approach to secure the unmanned aerial vehicle (UAV) communication by leveraging jamming from other nearby UAVs to defend against the eavesdropping. In particular, we consider a two-UAV scenario when one UAV transmitter delivers the confidential information to a ground node (GN), and the other UAV jammer cooperatively sends the artificial noise to con... View full abstract»