Explore the vast range of titles available.

Increased capacity, higher data rate, decreased latency, and better service quality are examples of the primary objectives or needs that must be catered to in the near future, i.e., fifth-generation (5G) and beyond. To fulfil these needs, cellular network design must be drastically improved. The 5G cellular network design, huge multiple-input multiple-output (MIMO) technology, and device-to-device communication are all highlighted in this comprehensive study. Hence, free-space optics (FSO) is a promising solution to address this field. However, FSO standalone is insufficient during turbulent weather conditions. FSO systems possess some limitations, such as being able to be disturbed by any interference between sender and receiver such as a flying bird and a tree, as it requires line-of-sight (LOS) connectivity. Moreover, it is sensitive to weather conditions; the FSO performance significantly decreases in bad weather conditions such as fog and snow; those factors deteriorate the performance of FSO. This paper conducts a systematic survey on the existing projects in the same area of research such as the hybrid FSO/Radio frequency (RF) communication system by listing each technique used for each model to achieve optimum performance in terms of data rate and Bit Error Rate (BER) to be implemented in 5G networks.

In this work the problem of selective backhauls in the transport of fresh products is investigated for the case of a large Belgian grocery retailer. Explicit measures for estimating the risk involved in certain route - vendor backhauling combinations, which emerge from the uncertainties involved in over road transport and unforeseen waiting and loading/unloading times at the depot or stores, are constructed. Two different models are proposed: an integer linear program with chance constraints, and a stochastic linear program. The chance constraints in the first model are based on the intuition and experience of the people in planning and dispatching. In the second model, the balance between risk and potential profit is directly incorporated into the objective function. For this study, the largest of all transport companies working for the studied retailer is considered for reference and data. The stochastic linear program proved to be superior. Moreover, we demonstrate that, even if only considering a small part of the fleet, the potential profits and reduction in empty kilometers due to the selected backhauls are considerable.

Fibreless optics or free space optical communications (FSOC) has been at the forefront of many academic research in telecommunications due to its numerous benefits of large spectrum, high-speed data transmission, security, low transmit power, unlicensed spectrum and non-interfering links. Among the technical challenges of dense deployment of small cells in heterogeneous networks (HetNet) is a flexible and cost-effective backhaul link. This paper proposes, designs, simulates and evaluates the performance of a 350 m FSOC link under different atmospheric impairments for picocell to macrocell backhauling applications. The performance of the FSOC link is assessed by evaluating bit error rate (BER), eye diagram and quality factor (Q-factor). Results obtained recommend the FSOC link deployment for pico-macrocell backhauling under the weather conditions of clear sky with/without turbulence, heavy rain, heavy haze, heavy fog and wet snow.

In this paper, we investigate the Multi-Depot Heterogeneous VRP with Backhauls. Though the problem is a generalisation of three existing routing problems, this is the first time this combined routing problem is investigated. A mathematical formulation is first presented followed by some tightening. A powerful and novel hybridisation of Variable Neighbourhood Search (VNS) with the Greedy Randomized Adaptive Memory Programming Search is proposed. As there are no problem instances available for bench-marking and evaluation purposes, we generated data sets by combining those from existing vehicle routing problems. The proposed meta-heuristic obtains a number of optimal solutions for small instances and yields about 13% gap from the lower bounds compared to nearly 40% and 20% average gap values for our CPLEX implementation and the VNS without hybridisation, respectively.

Transportation of renewable wood is increasing, being a necessary operation in logistics of the environmentally sustainable forest industry. However, increasing the transportation capacity is a source of greenhouse gas emissions. In addition to trucks’ emissions, maintaining road infrastructure affects the environment by the emissions of increasing utilization of HCT (high-capacity transportation), that is, larger and heavier vehicles, affecting the backhauling transportation and the efficiency of road-network combinations. Environmental efficiency is an important metric which is used for comparisons among technological alternatives employed in the utilization of energy derived from both fossil and renewable resources. Based on the enterprise resource planning (ERP) data (2018–2020), CO2 emissions of increasing HCT were calculated for a forest industry corporation. The reduction in average fuel consumption (ml t × km−1), between 52% and 70% in backhauling transportation, was 18.88%. In this respect, CO2 emissions were reduced by 4.52 g t × km−1, achieving 19.48 g t × km−1, based on the data from the 76 t vehicle combinations. Furthermore, the metric of total environmental efficiency shows the potential of the alternative road-network combinations for the HCT. The environmental efficiency of the 92 t HCT increased by 11% via an intensive road-network combination, compared to the most efficient 76 t HCT alternative and the efficiency increased by 21%, compared to the most efficient line-hauling alternative. Thus, the results are in favor of the backhauling transportation by the means of 92 t vehicles for HCT development. Furthermore, a sensitivity analysis demonstrates that technological improvement of the forest roads is essential for HCT in an increasing harvesting of renewable wood energy. Also, to achieve the maximum environmental efficiency of the HCT during upgrading of the forest roads, efficiency measurements of the HCT should be implemented in the transportation planning systems.

We describe self-organizing network (SON) concepts and architectures and their potential to play a central role in 5G deployment and next-generation networks. Our focus is on the basic SON use case applied to radio access networks (RAN), which is self-optimization. We analyze SON applications’ rationale and operation, the design and dimensioning of SON systems, possible deficiencies and conflicts that occur through the parallel operation of functions, and describe the strong reliance on machine learning (ML) and artificial intelligence (AI). Moreover, we present and comment on very recent proposals for SON deployment in 5G networks. Typical examples include the binding of SON systems with techniques such as Network Function Virtualization (NFV), Cloud RAN (C-RAN), Ultra-Reliable Low Latency Communications (URLLC), massive Machine-Type Communication (mMTC) for IoT, and automated backhauling, which lead the way towards the adoption of SON techniques in Beyond 5G (B5G) networks.

Fixed Point-to-Point microwave wireless systems with high spectral efficiency are needed to meet the pervasive and increasing demand for capacity in back-haul networks of mobile radio systems. In this context, spatially multiplexed LoS-MIMO (Line-of-Sight Multiple Input Multiple Output) systems have been studied for about twenty years, particularly in the millimeter wave frequency bands (above 15 GHz). However, their deployment in real networks has been really limited, to the authors’ knowledge. This has been due to several factors, i.e. the practical possibility of using extremely high-level modulation formats (nowadays up to 8192-QAM), the joint use of co-channel dual polarization, and the availability of wider channel bands in the new high frequency ranges (e.g. E-Band). In addition, a crucial reason has been the difficulty of installing multiple antennas spaced apart in order to maximize the MIMO spatial multiplexing so providing the maximum capacity gain. This optimal antenna separation, even for the classical MIMO M × N with M = 2 antennas at the receiver and N = 2 antennas at the transmitter, can be several meters, e.g. 5.71 m at 23 GHz on a 5 km link. In this article, we analyze the performance of LoS-MIMO systems where antenna separation is highly sub-optimal, for limiting the array size, and a satisfactory performance is made possible by the exploitation of specific bit loading and power allocation strategies and the setting of the working region of the RF transmitter power amplifiers to operate at a given Signal-to-Inter Modulation Distortion Ratio (SIMDR). The result is an overview of the advantages and drawbacks of compact LoS-MIMO from a wider perspective than in the existing literature, including fundamental aspects for the practical implementation of these systems. Performance is discussed in many cases of interest and compared with the state of the art SISO (Single Input Single Output) system.

Limited terrestrial network coverage in rural and remote areas constitutes a significant barrier to the digital transformation of the agricultural sector. Smart and precision farming applications, ranging from conventional environmental monitoring systems to advanced Digital Twin solutions, rely on the reliable transmission of sensor data, images, and video streams from geographically isolated farms. Such data-intensive services cannot be effectively supported without a robust communication infrastructure. Non-Terrestrial Networks (NTNs), particularly satellite systems, offer both narrowband and broadband connectivity, enabling the transmission of low-rate sensor measurements, as well as high-throughput multimedia data from the field. This paper presents an experimental performance evaluation of two satellite backhauling solutions: a Geostationary Earth Orbit (GEO) system provided by SES and a Low Earth Orbit (LEO) system from Starlink. The networks were first deployed and tested in a laboratory environment and subsequently validated in an operational agricultural field setting. Their performance is benchmarked against a terrestrial cellular network to assess their suitability for supporting advanced agricultural applications. The performance assessment results indicate that both satellite backhauling solutions are reliable and capable of meeting the bandwidth and latency requirements of delay-tolerant agricultural applications. In addition to the technical evaluation, this work presents a cost–benefit analysis that further underscores the advantages of NTN-based solutions. Despite higher initial expenditures, they provide extended coverage in remote areas and enable cost sharing across multiple users, improving overall economic viability.

In this paper, a massive MIMO enabled backhaul model for two-tier heterogeneous networks with in-band full-duplex transmission and imperfect CSI is provided. Because of a massive number of antennas at the macro base station and densification of small cells, circuit power consumption increases in the system. It is requisite to study energy efficiency of such backhaul networks. This paper aims at maximizing EE for optimal user association, spectrum allocation, and power allocation while accounting for QoS and backhaul constraints. A joint optimization problem is formulated as a non-convex mixed integer non-linear problem which provides an un-affordable computational complexity. To crack the problem efficiently, it is progressively divided into sub-problems until each one is convex and is solved separately to obtain the optimal solution. Furthermore, complexity of the proposed algorithm is evaluated and Jain’s fairness index is measured. Simulation results of the proposed distributive algorithm are shown and compared with that of the existing algorithm (Max SINR) to manifest the strength of the proposed algorithm. The impact of self-interference cancellation factor and channel estimation error on EE is clearly reflected by the numerical results. In addition, it is observed that using the proposed algorithm results in better EE than increasing the number of antennas.