A meta-parameter tuning model to improve the genetic algorithms design of labeling diversity mappers

Evolutionary algorithms (EAs) have recently been applied to Uncoded Space-Time Labeling Diversity (USTLD) systems to produce labeling diversity mappers. However, the most challenging task is choosing the best parameter setting for the EA to create a more ‘optimal’ mapper design. This paper proposes a ‘meta-Genetic Algorithm (GA)’ used to tune hyperparameters for the Labeling Diversity EA. The algorithm is examined on 16, 32 and 64QAM; 32 and 64PSK; 16, 32 and 64APSK and 16APSK constellations that do not show diagonal symmetry. Furthermore, the meta-GA settings and original GA settings are compared in terms of the number of generations taken to converge to a solution. For QAM constellations, the output using the meta-GA settings matched but did not improve with the original settings. However, the number of generations needed to converge to a solution took 120 times less than the number of generations using the original settings. In the 64PSK constellation, a diversity gain of [Formula: see text][Formula: see text]dB was observed while improving on the actual fitness value from 0.0575 to 0.0661. Similarly, with 32APSK constellation, an improvement in fitness value from 0.1457 to 0.1748 was made while showing diversity gains of [Formula: see text][Formula: see text]dB. 64APSK constellation fitness value improved from 0.0708 to 0.0957, and a [Formula: see text][Formula: see text]dB gain was observed. The most significant improvement was made by the asymmetric 16APSK constellation, with gains of [Formula: see text][Formula: see text]dB and increasing its fitness value three times (0.0981 to 0.3000). A study of the effects of optimizing the GA parameters shows that the number of swaps during crossover [Formula: see text] and the radius [Formula: see text] were the two most important variables to optimize when executing this GA.

Space-Time-Color (STC) Scheme with Symbol-Hopping for Color Shift Keying (CSK)Modulation

<div>This paper proposes a novel coding scheme for Visible Light Communications (VLC) systems using symbol mapping permutations on the color domain. The permutation is done through symbol-hopping over the points of an optimized 4-CSK constellation. This scheme provides diversity gains, promises robustness against monochromatic channel degradation, and increases the information security of the communication link. It can also be used in conjunction with Single-Input and Single-Output (SISO) systems, as well as in Multiple-Input and Multiple-Output (MIMO) systems. Monte Carlo computational simulations evaluate the performance of the proposed scheme over the conventional QuadLED (QLED) CSK system and other codes, showing superior coding and diversity gains over two direct competitors, under a Rician flat-fading channel.</div>

Space-Time-Color (STC) Scheme with Symbol-Hopping for Color Shift Keying (CSK)Modulation

<div>This paper proposes a novel coding scheme for Visible Light Communications (VLC) systems using symbol mapping permutations on the color domain. The permutation is done through symbol-hopping over the points of an optimized 4-CSK constellation. This scheme provides diversity gains, promises robustness against monochromatic channel degradation, and increases the information security of the communication link. It can also be used in conjunction with Single-Input and Single-Output (SISO) systems, as well as in Multiple-Input and Multiple-Output (MIMO) systems. Monte Carlo computational simulations evaluate the performance of the proposed scheme over the conventional QuadLED (QLED) CSK system and other codes, showing superior coding and diversity gains over two direct competitors, under a Rician flat-fading channel.</div>

Massive MIMO Techniques for 5G and Beyond—Opportunities and Challenges

Telecommunications have grown to be a pillar to a functional society and the urge for reliable and high throughput systems has become the main objective of researchers and engineers. State-of-the-art work considers massive Multiple-Input Multiple-Output (massive MIMO) as the key technology for 5G and beyond. Large spatial multiplexing and diversity gains are some of the major benefits together with an improved energy efficiency. Current works mostly assume the application of well-established techniques in a massive MIMO scenario, although there are still open challenges regarding hardware and computational complexities and energy efficiency. Fully digital, analog, and hybrid structures are analyzed and a multi-layer massive MIMO transmission technique is detailed. The purpose of this article is to describe the most acknowledged transmission techniques for massive MIMO systems and to analyze some of the most promising ones and identify existing problems and limitations.

Energy-balanced parameter-adaptable cooperative protocol (EBPACP) design in wireless sensor networks

The performance of WSNs is adversely affected by the radio irregularity and fading effect. Cooperative transmission has been proven to be an effective way to combat the impacts of fading by obtaining diversity gains and therefore reduces the transmit energy. Meanwhile, some sensor nodes have heavier burden than the others and the energy imbalance problem remains harmful to the system lifetime. How to efficiently incorporate cooperative transmission into WSNs and balance energy are the subjects of this thesis. In our research, we proposed an energy-balanced parameter-adaptable cooperative protocol (EBPACP) for cluster-based WSNs. Since the design of WSNs is highly dependent on application scenarios, we analyzed the effects of the system parameters and found a unified criterion to summarize the effects. With this knowledge, a preferred scheme of cooperative transmission is chosen to reduce energy consumption. How to form clusters, build up cooperative relationships and transmit data to the BS are explored in detail in the thesis. We use the idea of weighted distance to adjust the size of the cluster. Thus energy consumption is balanced by adjusting energy dissipated inside and outside of the clusters. Sensor nodes consuming higher energy in outside-cluster communication form smaller clusters. In this thesis, EBPACP is mainly discussed in single-hop systems and it can be extended to multi-hop systems. Simulation results have shown that the proposed EBPACP provides good system performance in terms of energy efficiency and energy balance.

Energy-balanced parameter-adaptable cooperative protocol (EBPACP) design in wireless sensor networks

The performance of WSNs is adversely affected by the radio irregularity and fading effect. Cooperative transmission has been proven to be an effective way to combat the impacts of fading by obtaining diversity gains and therefore reduces the transmit energy. Meanwhile, some sensor nodes have heavier burden than the others and the energy imbalance problem remains harmful to the system lifetime. How to efficiently incorporate cooperative transmission into WSNs and balance energy are the subjects of this thesis. In our research, we proposed an energy-balanced parameter-adaptable cooperative protocol (EBPACP) for cluster-based WSNs. Since the design of WSNs is highly dependent on application scenarios, we analyzed the effects of the system parameters and found a unified criterion to summarize the effects. With this knowledge, a preferred scheme of cooperative transmission is chosen to reduce energy consumption. How to form clusters, build up cooperative relationships and transmit data to the BS are explored in detail in the thesis. We use the idea of weighted distance to adjust the size of the cluster. Thus energy consumption is balanced by adjusting energy dissipated inside and outside of the clusters. Sensor nodes consuming higher energy in outside-cluster communication form smaller clusters. In this thesis, EBPACP is mainly discussed in single-hop systems and it can be extended to multi-hop systems. Simulation results have shown that the proposed EBPACP provides good system performance in terms of energy efficiency and energy balance.

Linear and Decoupled Decoders for Dual-Polarized Antenna-Based MIMO Systems

Quaternion orthogonal designs (QODs) have been used to design STBCs that provide improved performance in terms of various design parameters. In this paper, we show that all QODs obtained from generic iterative construction techniques based on the Adams-Lax-Phillips approach have linear and decoupled decoders which significantly reduce the computational complexity at the receiver. Our result is based on the quaternionic description of communication channels among dual-polarized antennas. Another contribution of this work is the linear and decoupled decoder for quasi-orthogonal codes for non-square as well as square designs. The proposed solution promises diversity gains with the quaternionic channel model and the decoding solution is independent of the number of receive dual-polarized antennas. A brief comparison is presented at the end to demonstrate the effectiveness of quaternion designs in two dual-polarized antennas over available STBCs for four single-polarized antennas. Linear and decoupled decoding of two quasi-orthogonal designs is shown, which has failed to exit previously. In addition, a QOD for 2×1 dual-polarized antenna configuration using quaternionic channel model shows a 3 dB gain at 10−5 in comparison to the same code evaluated for 2×2 complex representation of the quaternionic channel. This gain is further enhanced when the received diversity for these the cases is matched i.e., 2×2. The code using the quaternionic channel model shows a further 13 dB improvement at 10−5 BER.