K. Wane Keita

Bio: K. Wane Keita is an academic researcher from Cheikh Anta Diop University. The author has contributed to research in topics: Relay & Low-density parity-check code. The author has an hindex of 1, co-authored 3 publications receiving 1 citations.

Performance of Hybrid RF/FSO Cooperative Systems Based on Quasicyclic LDPC Codes and Space-Coupled LDPC Codes

Abstract: Free space optical (FSO) communication systems provide wireless line of sight connectivity in the unlicensed spectrum, and wireless optical communication achieves higher data rates compared to their radio frequency (RF) counterparts. FSO systems are particularly attractive for last mile access problem by bridging fiber optic backbone connectivity to RF access networks. To cope with this practical deployment scenario, there has been increasing attention to the so-called dual-hop (RF/FSO) systems where RF transmission is used at a hop followed by FSO transmission to another. In this article, we study the performance of cooperative transmission systems using a mixed RF-FSO DF (decode and forward) relay using error-correcting codes including QC-LDPC codes at the relay level. The FSO link is modeled by the gamma-gamma distribution, and the RF link is modeled by the Additive White Gaussian Noise (AWGN) model. Another innovation in this article is the use of cooperative systems using a mixed FSO/RF DF relay using quasicyclic low-density parity check (QC-LDPC) codes at the relay level. We also use the space-coupled low-density parity check (SC-LDPC) codes on the same scheme to show its importance in cooperative optical transmission but also in hybrid RF/FSO transmission. The latter will be compared with QC-LDPC codes. The use of mixed RF/FSO cooperative transmission systems can improve the reliability and transmission of information in networks. The results demonstrate an improvement in the performance of the cooperative RF/FSO DF system based on QC-LDPC and SC-LDPC codes compared to RF/FSO systems without the use of codes, but also to the DF systems proposed in the existing literature.

Performance Analysis of Mixed MIMO RF/FSO DF Relaying Based on Globally Coupled Low Density Parity Check (GC-LDPC) Codes

Abstract: In this work, we analyze the performance of the use of error correcting codes in particular the LDPC codes with global coupling (GC-LDPC) in a double-hop relay system composed of links with multiple inputs and multiple outputs at radio frequency / free space optics (MIMO-RF/FSO). A multiantenna listener listens to the information by decoding the signals received from the source node. In addition, to decode the signals we use two-phase local-global decoding. To eliminate interference in the first hop we use the interference alignment technique (IA) we also assume that the source-relay link undergoes Rayleigh fading, and that the relay-destination link is affected by the degradations of the channel optics, including path loss, atmospheric turbulence, and pointing errors. Using DF relay technology, mixed MIMO-RF/FSO systems combine the advantages of RF and FSO communication technologies. The use of mixed MIMO-RF/FSO cooperative transmission systems can improve network reliability and transmission. Results demonstrate improved performance of MIMO-RF/FSO DF cooperative relay system based on GC-LDPC codes with multiple antennas compared to MIMO-RF/FSO systems without the use of GC-LDPC codes, but also to systems SISO (Single-Input Single-Output) RF-FSO DF proposed in the existing literature.

Performance of Cooperative System Based on LDPC Codes in Wireless Optical Communication

Abstract: This paper proposes the use of the technique of cooperative systems in wireless optical communication. Several obstacles can degrade the performance of information transmission in wireless optical links. These include atmospheric turbulence in communication links greater than 1 km, the rocking of buildings, wireless optical channel fading and flickering. Several studies have shown that the use of cooperative systems in this communication technique has better performance compared to conventional systems. To improve the performance of the transmission in the optical links we propose to place a DF (Decode and Forward) relay between the transmitter and the receiver, using the LDPC (Low-density Parity-check) codes at the relay level. Another innovation of this article is the introduction of the series relays to connect two very distant sites by also using LDPC at the level of each relay. Our method achieves a remarkable efficiency in terms of BER (Bit Error Rate) compared to some previous work.

Performance of Hybrid RF/FSO Cooperative Systems Based on Quasicyclic LDPC Codes and Space-Coupled LDPC Codes

Abstract: Free space optical (FSO) communication systems provide wireless line of sight connectivity in the unlicensed spectrum, and wireless optical communication achieves higher data rates compared to their radio frequency (RF) counterparts. FSO systems are particularly attractive for last mile access problem by bridging fiber optic backbone connectivity to RF access networks. To cope with this practical deployment scenario, there has been increasing attention to the so-called dual-hop (RF/FSO) systems where RF transmission is used at a hop followed by FSO transmission to another. In this article, we study the performance of cooperative transmission systems using a mixed RF-FSO DF (decode and forward) relay using error-correcting codes including QC-LDPC codes at the relay level. The FSO link is modeled by the gamma-gamma distribution, and the RF link is modeled by the Additive White Gaussian Noise (AWGN) model. Another innovation in this article is the use of cooperative systems using a mixed FSO/RF DF relay using quasicyclic low-density parity check (QC-LDPC) codes at the relay level. We also use the space-coupled low-density parity check (SC-LDPC) codes on the same scheme to show its importance in cooperative optical transmission but also in hybrid RF/FSO transmission. The latter will be compared with QC-LDPC codes. The use of mixed RF/FSO cooperative transmission systems can improve the reliability and transmission of information in networks. The results demonstrate an improvement in the performance of the cooperative RF/FSO DF system based on QC-LDPC and SC-LDPC codes compared to RF/FSO systems without the use of codes, but also to the DF systems proposed in the existing literature.

A Free Space Optic/Optical Wireless Communication: A Survey

Abstract: The exponential demand for the next generation of services over free space optic and wireless optic communication is a necessity to approve new guidelines in this range. In this review article, we bring together an earlier study associated with these schemes to help us implement a multiple input/multiple output flexible platform for the next generation in an efficient manner. OWC/FSO is a complement clarification to radiofrequency technologies. Notably, they are providing various gains such as unrestricted authorizing, varied volume, essential safekeeping, and immunity to interference.

Connecting the Universe: Challenges, Mitigation, Advances, and Link Engineering

Abstract: With the large number of deep space (DS) missions anticipated by the end of this decade, reliable-high capacity DS communication systems are needed more than ever. Nevertheless, existing DS communication technologies are far from meeting such a goal. Improving current systems does not only demand a system engineering leadership, but more crucially a well investigation in the potentials of emerging technologies in overcoming the challenges of the unique-ultra long DS communication channel. This project starts with a survey that highlights current technologies, trends, and advancements, investigates potentials, and identify challenges, and in essence, provide perspectives and propose solutions. It focuses on free-space optical (FSO) communication as a potential technology that can overcome the shortcomings of current radio frequency (RF)-based communication systems. To the best of our knowledge, in addition, it provides for the very first time a thoughtful discussion about implementing orbital angular momentum (OAM) for DS, identifies major related challenges, and proposes some novel solutions. Furthermore, we discuss DS modulations and coding schemes, as well as emerging receiver technologies and communication protocols. We also elaborate on how all of these technologies guarantee reliability, improve efficiency, offer capacity boosts, and enhance security in the unique DS environment. In addition to that, an extended study on the design and performance analysis of deep space optical communication (DSOC) is included, with the most suggested modulation for such a link being pulse position modulation (PPM) and a focus on the communication between Earth and the planet Mars, which is an important destination for space exploration.

Matryoshka Globally-Coupled LDPC Code

Abstract: This paper proposes a new low-density parity-check (LDPC) code called Matryoshka globally-coupled (MGC) LDPC code. We give the definition of $N$ -fold MGC-LDPC code which consists of $N$ layers Matryoshka-style codes, i.e., $\mathcal {C}_{\mathrm {mgc}}\left ({1}\right), \mathcal {C}_{\mathrm {mgc}}\left ({2}\right),\ldots,\mathcal {C}_{\mathrm {mgc}}\left ({N}\right)$ . Moreover, the $N$ Matryoshka-style codes can form a Matryoshka chain $\mathcal {C}_{\mathrm {mgc}}\left ({1}\right) \prec \mathcal {C}_{\mathrm {mgc}}\left ({2}\right) \prec \cdots \prec \mathcal {C}_{\mathrm {mgc}}\left ({N}\right)$ , which indicates that a high-layer Matryoshka-style code contains a low-layer Matryoshka-style code just like the Matryoshka dolls. Thus, the proposed $N$ -fold MGC-LDPC code naturally has rate-compatible feature. Based on the superposition (SP) construction, we present truncating and masking methods to construct the base matrices (BMs) of MGC-LDPC codes. More importantly, we introduce the double lower triangular (DLT) form of parity-check matrix for further developing a recursive encoding scheme for MGC-LDPC codes. With the help of the proposed encoding scheme, the local codes of MGC-LDPC code can be independently encoded, and the $n$ th layer Matryoshka-style codeword can be recursively obtained by the $\left ({n - 1}\right)$ th layer Matryoshka-style code and the local codes in $n$ th layer Matryoshka-style code for $2 \leq n \leq N$ . Simulations show that MGC-LDPC codes can perform well over both the additive white Gaussian noise channel (AWGNC) and binary erasure channel (BEC), and provide a flexible rate-compatible feature to satisfy the requirements of different scenarios.

A Novel Association Rules Mining Based on Improved Fusion Particle Swarm Optimization Algorithm

Abstract: Association rule learning is to mine the correlation between items and objects from certain data or other information carriers, and the results can reveal the hidden association patterns in the data. This paper firstly analyzes the advantages and disadvantages of the traditional particle swarm optimization algorithm, and finds the existing problems. Aiming at these problems, this paper improves the particle swarm optimization algorithm based on the random search theory of complex groups. In this paper, the improved fusion particle swarm optimization algorithm is used in the association rule mining model, and more effective rules can be obtained. Experiments show that the improved fusion particle swarm optimization algorithm proposed in this paper is feasible and efficient in mining association rules.