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Wireless communication is an essential technology to unlock the full potential of unmanned aerial vehicles (UAVs) in numerous applications and has thus received unprecedented attention recently. Although technologies such as direct link, WiFi, and satellite communications are still useful in some remote scenarios where cellular services are unavailable, it is believed that exploiting the thriving 5G and beyond cellular networks to support UAV communications is the most promising and cost-effective approach, especially when the number of UAVs grows dramatically. On the one hand, to guarantee safe and efficient flight operations of multiple UAVs, it is of paramount importance to provide secure and ultra-reliable communication links between the UAVs and their ground pilots or control stations for conveying command and control signals, especially in beyond-visual-line-of-sight (BVLOS) scenarios. On the other hand, because of advances in communication equipment miniaturization as well as UAV manufacturing, mounting compact and lightweight base stations (BSs) or relays on UAVs becomes increasingly feasible. This has led to two promising research paradigms for UAV communications, namely, UAV-assisted cellular communications and cellular-connected UAVs, where UAVs are integrated into cellular networks as aerial communication platforms and aerial users, respectively. As such, integrating UAVs into cellular networks is believed to be a win-win technology for both UAV-related industries and cellular network operators, which not only creates plenty of new business opportunities but also benefits the communication performance of 3-D wireless networks. In addition, UAV related sensing and computing are also helpful for achieving efficient and reliable communication (e.g., in avoiding coverage holes) as well as smart UAV coordination, positioning, and trajectory design. However, 5G and beyond wireless networks with UAVs significantly differs from traditional communication systems, because of the high altitude and high maneuverability of UAVs, the unique UAV-ground channels, the diversified quality of service (QoS) requirements for downlink command and control (C&C) and uplink mission-related data transmission, the stringent constraints imposed by the size, weight, and power (SWAP) limitations of UAVs, as well as the new design degrees of freedom enabled by joint UAV mobility control and communication resource allocation.

The program “Digital Economy of the Russian Federation” approved the Concept for the creation and development of 5G / IMT-2020 networks. The development of 5G communications will significantly impact the implementation of many innovative projects and initiatives: the Smart City project, Unmanned Transport, etc. Along with significant technical advantages compared to previous generations of communication (2G, 3G, 4G), 5G technology has completely different emitting characteristics: more emitting elements, signal modulation, three-dimensional beam, the ability to control the beam, SHF (ultra-high) and EHF (extremely high) radio frequency ranges and centimetre and millimetre wavelengths of electromagnetic radiation. Therefore, it is becoming an especially urgent problem to ensure exposure to the human body of non-ionizing electromagnetic fields of the radio frequency range (30 kHz–300 GHz). The authors searched the literature on the biological effects of 5G cellular communications and electromagnetic radiation in the centimetre and millimetre ranges using the appropriate keywords in PubMed search engines, Scopus, Web of Science, Medline, The Cochrane Library, EMBASE, Global Health, CyberLeninka, RSCI and others. There is currently tentative and conflicting evidence on the impact of 5G. The rapidly growing density of wireless devices and antennas (considering future 5G networks) increases the public health risk from exposure to RF EMFs as the penetration depth for 5G EHF radiation is only a few millimetres. At these wavelengths, resonance phenomena are possible at the cellular and molecular levels, particularly concerning stimulating SHF and EHF oxidative processes and damaging DNA. The influence of the millimetre range of RF-EMF is poorly understood; oncological and non-oncological (impact on the reproductive, immune systems, etc.) effects are possible. Using numerical simulation methods of EMF radiation resonances on insects, Thielens A et al., 2018, found a significant overall increase in the absorbed RF power at a frequency of 6 GHz and higher than a frequency below 6 GHz. Contribution: Egorova A.M. — collection of literature data, approval of the final version of the article, responsibility for the integrity of all parts of the article; Lutsenko L.A. — editing, approval of the final version of the article; Sukhova A.V. — text writing, editing; Kolyuka V.V. — collection of literature data; Turdyev R.V. — collection of literary data, text writing. All authors are responsible for the integrity of all parts of the manuscript and approval of the manuscript final version. Conflict of interest. The authors declare no conflict of interest. Acknowledgment. The study had no sponsorship.

The role that the cellular phone plays in our daily lives is constantly evolving. Conceived as a "mobile" telephone to contrast with a "tethered" telephone, the cell phone functions as a personal assistant, a music player, and a camera, while expanding its primary role as a wireless data transceiver. On average, there is more than one mobile phone per person in this world. Thanks to this all-pervasive reach, several essential services-for example, banking and health care-are now delivered to end users through their cell phones. The protocols or standards governing cellular communication are continually evolving to support this changing landscape in a power-and spectralefficient manner. Mobile technology has witnessed five generations of evolution: from the mobile-phone era ushered in by 2G to the future smartphones that will be powered by the enhanced spectral efficiency of 5G.

Ad‐hoc networks provide a means for extending the range of wireless communications for unmanned aerial vehicles (UAVs). This chapter presents the fundamental concepts, challenges, and solutions to creating ad‐hoc networks with UAVs as nodes. It discusses the mobility models, applicable standards, and products that are available today for creating mesh networking of UAVs. Traditionally, communication support for UAVs comes from satellites operating at the geostationary orbit level. However, two additional communication strategies are also being investigated for UAVs: 4G/5G cellular communications operating on the ground and aerial networks and communications operating in the mid‐air. Mobility poses a huge challenge for aircraft‐to‐aircraft communications. Several technologies that can support ad‐hoc mesh networking have been evolved in recent years. Some of these products have been field‐tested for their applicability for UAV communications. The chapter provides a summary of commercial off‐the‐shelf products that can support ad‐hoc networking of UAVs.

Vehicle-to-vehicle (V2V) underlay cellular communication plays an important role in the fifth-generation (5G) and beyond communications and its security issues attract a lot of attention. Physical layer security, which explores channel characteristics to protect wireless communications, is very attractive due to its low latency. This paper focuses on secrecy capacity maximization in V2V underlay cellular communications, where the secrecy capacity of vehicular user equipments (VUEs) is optimized first, followed by sum proportional fairness function optimization for both VUEs and cellular user equipments (CUEs). The optimization problems can be solved in two sub-problems, e.g., power and subcarrier allocation problems. The power allocation can be done with the first strategy using a one-dimensional searching algorithm, whereas a genetic algorithm (GA) is used to solve the second optimization problem. In addition, as VUEs share uplink resources with CUEs, the co-channel interference exists and the subcarrier allocation sub-problem is a 3D search problem, which is solved by a two-step iterative Hungarian algorithm (IHA). Finally, simulations are performed to validate the performance of the proposed schemes.

Intelligent reflecting surfaces (IRSs) have emerged as a key enabler for beyond fifth-generation (B5G) communication technology and for realizing sixth-generation (6G) cellular communication. In addition, B5G and 6G networks are expected to support aerial user communications in accordance with the expanded requirements of data transmission for an aerial user. However, there are challenges in providing wireless communication for aerial users owing to the different radio wave propagation properties between terrestrial areas and aerial areas. In this article, we propose an IRS-aided cellular network coverage extension for aerial users. In our proposed network, IRS and base stations (BSs) cooperate with each other to provide air-ground communication to aerial users (AUs), the aim of which is to prevent interference signals from spreading to a wide area. Furthermore, IRS placement is designed to maximize the network performance in terms of the spatial signal-to-interference-plus-noise ratio (SINR) while mitigating inter-cell interference. Numerical analysis results indicate that the proposed IRS-aided network outperforms the benchmark system without IRSs when the IRS installation positions are optimally determined.

The fifth generation (5G) wireless communication networks are expected to support communications with high mobility, e.g., with a speed up to 500 km/h. Hence 5G communications will have numerous applications in high mobility scenarios, such as high speed railways (HSRs), vehicular ad hoc networks, and unmanned aerial vehicles (UAVs) communications [1] – [3] . The 5G systems will provide advanced communication platforms enabling reliable transmission for the Wireless Train Backbone (WLTB) or Wireless Train Control & Management System (WTCMS) [4] , [5] . They will also enable new services or enhancements for vehicular communications in Intelligent Transportation System (ITS) [6] – [9] . The coordination and swarming control for UAVs will also benefit from 5G capabilities, as UAV-based 5G infrastructure modeling and improvement have begun receiving attention [10] . In general, high mobility communication is not only about how large is the maximum speed, it is more about the challenges caused by mobility. In high mobility scenarios, a wireless channel is rapidly time varying, Doppler shifts and spreads can be much larger than those in cellular communications, and if modeled statistically, the channel will be non-wide-sense stationary (non-WSS) over a short time period. In addition, network topology can change quickly, and switching among base stations (BSs) and/or peer nodes can be more frequent, not forgetting 5G challenges in cross-border mobility [11] .

Future wireless cellular communication networks are expected to provide connectivity for massive machine-type communication (mMTC) devices. The main challenge of supporting mMTC traffic for a cellular network lies in the high density of these devices, which individually have relatively little data to transmit. This suggests the use of low overhead, grant-free access scheme for uplink data transmission, which, however, suffers from packet collisions when devices attempt to access the channel. In this article, we suggest the use of real-valued transmission together with widely linear (WL) reception for improving resource access and thus data throughput in the uplink of mMTC traffic scenarios. We show that not surprisingly, the WL scheme can virtually double the number of receive antennas at the base station (BS). We analyze the effect of this on the supported user density and data throughput for grant-free uplink transmission. As a specific example, we consider the narrowband Internet-of-Things (NB-IoT) cellular communication system, which already includes real-valued modulation modes. Our numerical results show that the supported user density and data throughput of grant-free NB-IoT systems can be significantly improved due to the use of WL receivers. For example, considering an NB-IoT system with 1% packet drop probability, we obtain a tenfold (for single-antenna BS) and a sixfold (for dual-antenna BS) increase in the supported user density by using WL receivers instead of their conventional linear counterparts.

Small cell networks are expected to heavily be deployed in wireless communication networks due to it ability to enhance signals quality and spectrum utilisation. However, interference is posing a major threat to wireless communication especially cellular femtocell networks whereby its performance is degraded in dense deployment areas. For this reason, an enhanced fractional frequency reuse approach is proposed in this paper to mitigate the interference in femtocell networks. This is achieved by dividing the service area and frequency into three regions and three sets whereby each set is allocated different frequency set. The femtocell location is later obtained and assigned frequency in accordance to the region. The proposed approach helps in reducing the interference, boost the signal to interference plus noise (SINR), and enhance the throughput.

Vehicular communication is one of the critical technologies in intelligent transportation system to provide connectivity between vehicles, road side units, and pedestrians. Multiple wireless accessing technologies designed to provide connectivity in vehicular networks such as conventional Wi-Fi, IEEE 802.11p, and cellular communications. Recently, cellular V2X (C-V2X) is standardized and designed by the third generation partnership project (3GPP) for automotive services. C-V2X supports two communication modes through a single platform to provide both Wi-Fi and cellular communication. LTE-V2X is the current 3GPPRelease 14 standard that has many enhancements to provide the new 3GPPRelease 16 for the new 5G radio generation. 5G-new radio (NR) is expected to address the automotive capabilities, improvement, and services for 2020 and beyond. 5G-NR becomes a competitive technology compared with other wireless technologies because of extensive coverage, high capacity, high reliability, and low delay support. In this paper, we propose the Optimizing of 5G with V2X, and analyzing the current V2X standards, introducing the development of 5G, challenges, features, requirements, design, and technologies.

Cognitive radio (CR) has been proposed as an innovation to improve the range use effectiveness by giving a sharp access of the unused/underutilized range to unlicensed clients. Then, coordinated multipoint joint transmission (JT) is another promising method to improve the presentation of cognitive radio system. In this paper, we propose a CR framework with coordinated mul-tipoint JT strategy. A logical model is created for the got signal-to-commotion proportion at a CR to decide the vitality recognition limit and the base number of required examples for vitality location based range detecting in a CR organize (CRN) with CoMP JT procedure. The exhibition of vitality identification based range detecting under the created expository model is assessed by recreation and saw as dependable. It is figured an enhancement issue for a CRN with coordinated multipoint JT strategy to design the channel assignment and client planning for expanding the base throughput of the clients.

Nowadays, the infrastructure for major broadband networking in cellular communication introduces 6G-Network in a box (6th Generation-NIB) mobile phone networks. As surveyed, the functional execution of 6G-NIB networks addresses several unresolved problems, like assigning power to all points, power management, and efficient distribution. Hence, these unresolved issues have been taken into consideration and resolved through an optimized power allocation and distribution system using the Quasi-Convex Problem-Solving approach of Serial Polynomial Programming (SPP). It helps to boost the energy level of all the points among the peer to peer network and spectral performance of 6G-NIB has been substantially improved without compromising the network Quality of Service (QoS). In considering the transmission power, QoS, and sequential interference elimination (SIE) constraints, To test the proposed power allocation structure and to demonstrate improved efficiency against the traditional method, the simulation environment has been analyzed using Monte Carlo Simulation. The outcomes indicate that the proposed SPP-based power optimization principle greatly enhances 6G -NIB enabled Internet of Things (IoT) network efficiency and performance effectively.

As the cellular wireless communication techniques grow rapidly, the cells become smaller than the traditional communication system, then the handover events are very frequent and need to support a large number of users, and handover detection has become a very active research direction in a mobile computing environment. In order to copy with the problem of frequent handover operations between base stations in current cellular communication networks as cybernetic systems, we propose a novel handover detection approach by integrating frequent trajectory patterns mining and location prediction techniques. The proposed model contains the following essential steps: (1) mining frequent trajectory patterns from large-scale historical trajectory databases by applying an improved Apriori-like rule-based machine learning algorithm, which finds the intersection of candidate items by applying the trajectory connection operation instead of calculating the support count of each trajectory patterns and the candidate items are considerably reduced; (2) discovering movement rules based on the frequent trajectory pattern set by finding the postfix items of given prefix items satisfying the minimum support threshold; (3) inferring the future locations of moving objects by applying the movement rules matching strategy; (4) determining whether or not to perform handover detection across base stations in a cellular network beyond the discovered prediction results, according to the coverage area of cellular networks. Extensive experiments were conducted on the mobile datasets and the experimental results demonstrate the advantages of the proposed algorithm from the following four aspects: (1) the accuracy of handover detection is above 95% at average which is a very satisfactory result in a mobile computing environment; (2) the time cost is less than 20 s when the number of movement rules and handover detection is 1000, which further shows the merit of the runtime performance of the proposed method; (3) the frequent-trajectory-patterns based handover detection algorithm can successfully avoid the ping-pong effect due to unnecessary handover operations; (4) and lastly significantly reduce the error rate of frequent handover decisions and the average unnecessary handover rate is lower than 0.05 when compared with the state-of-the-art methods.

While mode selection has been envisioned as the most cost-effective way to address the interference issue in Device-to-Device (D2D) communications, existing works have been largely conducted without consideration of the energy depletion of devices. In this paper we investigate simultaneous wireless information and power transfer (SWIPT) empowered mode selection based on stochastic geometry. As a mean of solving it, system energy efficiency is formulated by determining the closed-form ergodic energy-harvested and ergodic capacity of D2D and cellular users in reuse, dedicated, and cellular communication modes with the time switching and power splitting architectures of SWIPT. We then leverage the derived results, along with the energy efficiency to design an energy-efficient mode selection mechanism. Our simulation results show that the developed mechanism is able to select the best mode for D2D communication with better energy efficiency, especially in an ultra-dense cellular network as compared with a state-of-the-art mode selection approach.

Power allocation plays a vital role in coordinating interference between Device-to-Device (D2D) and cellular communications, and when power allocation meets simultaneous wireless information and power transfer (SWIPT), the energy efficiency of D2D communications can be significantly improved. While numerous research studies have been conducted on D2D power allocation, most of these studies do not take the presence of SWIPT into consideration. Toward a remedy for this issue, we investigate the problem of D2D power allocation with SWIPT power-splitting architecture, and address it by establishing a novel game-theoretic model. Two power allocation mechanisms are proposed to simultaneously allocate transmit power and choose power splitting ratio for D2D communications. We also develop two pricing strategies for the proposed power allocation mechanisms based on the social utility (sum utility of both D2D and cellular communications) maximization. Simulation results validate theoretical analyses and the effectiveness of the proposed mechanisms. In particular, we find through performance comparisons that our developed pricing strategies are light-weighted and energy-efficient, and the distributed power allocation mechanism is responsive to the mobility of D2D users. This work was supported by the Chongqing Key Laboratory of Computer Networking and Communications. The associate editor coordinating the review of this article and approving it for publication was M. Dong. (Corresponding author: Jun Huang.) Jun Huang is with the School of Computer Science, Chongqing University of Posts and Telecommunications, Chongqing 400065, China (e-mail: huangj@ieee.org).

The term 5G refers to the fifth generation of cellular wireless standards. Following the first four generations which focused on evolving voice and data communications, 5G is expected to greatly expand the range of possible domains to which cellular communications can be applied. The aim of this article is to present an introduction to some guiding principles that provide shape to the physical layer of the 5G standard.

A lot of effort and time is utilized in the planning and building of the cellular wireless networks to use minimum infrastructural components to provide the best network coverage as well as delivery of quality of service. Generally, path loss models are used for the prediction of wireless network coverage. Therefore, detailed knowledge of the appropriate path loss model suitable for the proposed geographical area is needed to determine the coverage quality of any wireless network design. However, to the best of our knowledge, despite the importance of path loss models, as used for the prediction of wireless network coverage, there doesn't exist any comprehensive survey in this field. Therefore, the purpose of this paper is to survey the existing techniques and mechanisms which can be addressed in this domain. Briefly, the contributions of this paper are: (1) providing a comprehensive and up to date survey of the various network coverage prediction techniques, indicating the different frequency ranges the models were developed, (2) the different suitable terrains for each of the model and the best suit mobile generation were presented, and lastly, (3) providing comparative analysis to aid the planning and implementation of the cellular networks.

The paper considers a method for determining power losses of signal propagation in a cellular system. The new century is characterized by the rapid introduction of cellular communications in all areas of human life. The cellular signal transmission paths from a transmitter to a receiver may be different: from a line-of-sight to а densely built-over locality. Unlike fixed-line wiring, wireless radio channels have random parameters that are difficult to analyze. That is why radio link modeling is the most difficult task when designing cellular communication systems. Most cellular systems operate in cities where there is no direct vision between antennas of a base and mobile stations. In addition, the presence of high buildings leads to large diffraction losses. Also, the interference of radio waves due to re-reflection from different objects causes a significant change in the signal level. One of the promising fields of modern technology is artificial neural networks. An important feature of neural networks is the parallel processing of information by a large number of neurons at the same time. Typical tasks that can be solved using neural networks are: control, encoding and decoding of information, classification, forecasting, automation of a decision-making process, pattern recognition and more. Neural networks are used in telecommunication systems to solve the following tasks: traffic control, channel allocation, switching, and adaptive routing. The paper proposes to use a neural network for increasing the accuracy of power loss determining for cellular system signal propagation. After creating a software or hardware solution for the neural network, a mathematical model of the network must be created and the network training must be performed. The proposed neural network is a multilayer perceptron. The paper presents the proposed architecture of the perceptron. The number of neurons in all the layers has been substantiated. The operation of the multilayered perceptron has been described.

Unmanned aerial vehicle (UAV) can enable cellular mobile communications in unexpected or temporary scenarios, but there are information security problems raised in such applications. Physical layer security is now emerging as a promising alternative technology to realize secrecy in wireless communications. In the UAV-enabled communication systems, the fully controllable mobility of UAV provides new design degrees of freedom for enhancing physical layer security. This paper investigates an UAV-enabled cellular communication system where an ultralow-altitude UAV is equipped with a base station to serve a ground user in the presence of an eavesdropper. The probability of non-zero secrecy capacity is maximized subject to the airspace and obstacle constraints by adaptively optimizing the UAV's three-dimensional positions. The optimization problem is simplified by equivalent transformation and then solved by semidefinite relaxation (SDR). Two approaches termed as eigenvector approximation and random sampling are addressed to extract an approximation solution for the primal problem from the solution obtained by the SDR. Simulation results show that there is a slight difference between the probability of non-zero secrecy capacity achieved by the two solution approximation approaches.

Exploiting unlicensed spectrum bands for cellular communication is a rapidly embraced trend by industry stakeholders. Accordingly, the specifications of Long Term Evolution (LTE) were extended in Release 13 to allow unlicensed spectrum operation, also known as LTE-Licensed Assisted Access (LAA). LTE is widely adopted, and there is a potential for significant coexistence impact of LTE-LAA on users of unlicensed spectrum including wireless medical devices, whether adopters of the new technology or incumbents. Therefore, work was initiated to revise and update the American National Standards Institute (ANSI) C63.27 standard for evaluation of wireless coexistence. This paper details the experimental work conducted at the Electromagnetic Compatibility and Wireless Laboratory, U.S. Food and Drug Administration, to investigate the use of LAA signals for wireless coexistence testing. A software defined radio platform was deployed to generate realistic LAA signals and measure the wireless coexistence impact on the LAA communication link. The equipment under test (EUT) used IEEE 802.11ac as an example incumbent technology in the 5 GHz band. The standardized radiated anechoic chamber method was used for testing. Results highlight the mutual coexistence impact of LAA in the 5 GHz band and suggest that selecting an LAA signal with the maximum possible channel time occupancy and the highest possible modulation and coding scheme (MCS) yields the most impactful coexistence situation on both the EUT and the LAA system.

A practical technique for the worst-case evaluation of levels of electromagnetic background generated by cellular communication systems is proposed. It is based on the analysis of the average electromagnetic loading on area created by base and mobile subscriber's stations, and on the prediction of the area traffic capacity created by wireless information services supported by cellular communications. Such evaluations are very important for supporting the intersystem EMC, electromagnetic safety and ecological compatibility of 4G/5G/6G systems

Multi Input Multi Output MIMO and Orthogonal Frequency Division Multiplexing OFDM based communication strategies have gained popularity in the industry and research fields due to the rising demand for wireless cellular communication. Massive MIMO-OFDM-based cellular communication has recently become popular in a variety of realtime applications. However, as the need for high-quality communication grew, so did the number of users, posing various problems. In this article, we presented a comprehensive review study about Massive MIMO-OFDM based communication techniques and development. We mainly focus on essential parameters of Massive MIMO-OFDM, which play an essential role in 5G communication such as PAPR, precoding, channel estimation, and error-correcting codes. The paper shows results on the energy efficiency for a wireless (MIMO) link operating at millimeter-wave frequencies (mmWave) in a typical 5G scenario, showing the impact of the above essential parameters on the 5G performance. This comprehensive review and comparison will research 5G development and applications to adopt the proper techniques to achieve their demand.

Στα ασύρματα δίκτυα επικοινωνιών, με πλήρη ανασχεδιασμό της διάρθρωσης, λειτουργίας και κατανομής των πόρων αυτού του ιδιαιτέρως περίπλοκου μηχανισμού σε όλα τα επίπεδα λειτουργίας του, μπορεί να εξοικονομηθεί σημαντικό ποσοστό της καταναλισκόμενης ενέργειας. Κατάλληλες υποδομές ανταλλαγής και λήψης αποφάσεων, οι οποίες θα παρέχουν στο σύστημα διαχείρισης του εκάστοτε δικτύου τη δυνατότητα να γνωρίζει το βέλτιστο τρόπο με τον οποίο θα μπορεί να ανταποκριθεί στις συνεχώς μεταβαλλόμενες ανάγκες και συνθήκες του περιβάλλοντός του, κρίνονται απαραίτητες και πρέπει να υλοποιηθούν διότι θα συμβάλλουν στην επίτευξη υψηλού βαθμού βελτιστοποίησης της ενεργειακής απόδοσης των ασύρματων δικτύων τηλεπικοινωνιών. Η παρούσα Διδακτορική Διατριβή εστιάζει στην ενεργειακά αποδοτική λειτουργία των δικτύων κινητής, που είναι μία εκ των δύο σημαντικότερων τεχνολογιών ασύρματης πρόσβασης. Εστιάσαμε στην αναθεώρηση του τρόπου λειτουργίας των σημείων ασύρματης πρόσβασης, τα οποία αναλίσκουν το 80% της απαιτούμενης ενέργειας για την ομαλή λειτουργία ενός δικτύου κινητής. Προτείναμε νέα προφίλ λειτουργίας, εκπομπής και εξυπηρέτησης της τηλεπικοινωνιακής κίνησης στο σύνολο των σημείων πρόσβασης, στοχεύοντας στην υψηλότερη μείωση της ενεργειακής τους κατανάλωσης, με παράλληλη παρακολούθηση και διατήρηση του επιπέδου των υπηρεσιών που προσφέρεται στον τελικό χρήστη. Από θεωρητική προσέγγιση, αποδείξαμε ότι το συγκεκριμένο μοντέλο προσέγγισης της μείωσης της ενεργειακής κατανάλωσης των δικτύων κινητής εντάσσεται στην κατηγορία προβλημάτων χωρητικότητας και χωροθέτησης που ανήκει στην κατηγορία NP-Δύσκολων προβλημάτων. Εφαρμόσαμε τεχνικές εύρεσης της μέγιστης ενεργειακής εξοικονόμησης σε καθένα από τα μοντέλα συστήματος δικτύων κινητής που εξετάσαμε, και διατυπώσαμε τα αντίστοιχα προβλήματα ενεργειακής βελτιστοποίησης. Εξετάσαμε ποικιλία παραμέτρων και εκδοχών στα ανωτέρω προβλήματα, όπως: α) ομογενή και ετερογενή μοντέλα τοπολογιών, β) διάφορες τεχνικές ραδιοπρόσβασης, γ) στατικά μοντέλα και μοντέλα κίνησης χρηστών, δ) διαφορετικής ποιότητας προσφερόμενες υπηρεσίες, καθώς και ε) εφαρμογή μοντέλων οπισθοζεύξεων, και αναδείξαμε ευριστικά σχήματα εξεύρεσης βέλτιστων ενεργειακά λύσεων, ικανά να ελαχιστοποιήσουν την ενεργειακή κατανάλωση των δικτύων κινητής ανά στιγμιότυπο ή ανά ημερήσιο κύκλο της λειτουργίας τους, διατηρώντας παράλληλα την ποιότητα των υπηρεσιών στα επιθυμητά επίπεδα., In wireless communication networks, with a full redesign in structure, operation and resources’ distribution at all levels of operation of this very complex mechanism, a significant amount of the consumed energy can be saved. Proper decision-exchange and support infrastructures, which will provide to the network management services the ability to meet the ever-changing needs and conditions of the environment, are considered as necessary, in order to achieve a high degree of energy efficiency optimization in wireless broadband communications. This PhD Dissertation focuses on energy-efficient operation of one of the most common wireless access technologies, namely mobile/cellular communications. We focused on the wireless access points’ operation, which consume up to 80% of the total energy required by an operational wireless mobile network. We introduced new operational, transmission and traffic load servicing profiles in the set of wireless access points, aiming at the higher reduction of their energy consumption, while maintaining and monitoring the level of services offered to the end user. From a theoretical perspective, we classified this particular energy aware model into the category of the capacitated facility location problems, which are NP-hard. We applied exhaustive techniques for estimating the upper bound in each of the mobile network’s system models we examined, and we formulated the corresponding power consumption optimization problems. We examined a variety of different parameters and variations, such as: a) homogeneous and heterogeneous topology models, b) different radio access techniques, c) static users and user mobility patterns d) variety of offered services, as well as and e) application of backhaul models, and introduced energy-efficient heuristic schemes capable of finding the optimal solution from a power consumption perspective, per snapshot and/or per daily operation of a wireless communication network, while maintaining the quality of services at the desired levels.

Future needs of wireless and cellular communication in current, as well as the next decade, require to support many services like system average throughput, mobile traffic explosion, live HD streaming, enhanced location-based services (LBS), M2M communication, cloud computing, etc. These bring many challenges in capacity, coverage, data rate, and spectral efficiency. Traditional Orthogonal Multiple Access techniques (OMA) can't fulfill these basic requirements of next generation networks. However, by allocating the same radio resources to many users, the system capacity and user throughput can be improved. Non-Orthogonal Multiple Access technique has recently been recommended for the fifth generation (5G) and beyond fifth generation networks (5G+) which can address such issues. By non-orthogonally allocating many users, the capacity and spectral efficiency can be improved. NOMA scheme can be categorized into two main classes: Power domain and Code Domain. This survey paper centers on the Power domain NOMA technique with superposition coding plus Successive interference cancellation at transmitter and receiver, respectively, as well as sum-rate analysis of NOMA in uplink and downlink. The blend of NOMA with MIMO and massive MIMO in addition to the performance of NOMA in the cellular network has been discussed and analyzed.

To support the increasing data traffic demand in wireless communications networks, a multi-tier architecture that consists of multiple small cells is adopted in traditional (macro) cellular networks. Nevertheless, due to the expansion of various wireless devices and services, there is still a need to increase the network capacity in new generation networks such as 5G. Hence, the integration of Device-to-Device (D2D) communication as a promising technology with heterogeneous networks has been proposed. This integration not only increases network capacity but also improves spectral efficiency and alleviates the traffic load of base stations. However, the co/cross-tier interferences between D2D and cellular communications caused by resource sharing is a significant challenge. In this paper, we propose a distributed resource allocation algorithm based on matching theory to minimize these interferences and optimize the network performance. It is shown in this paper that the proposed algorithm converges to a stable matching and terminates after finite iterations. Simulation results show that the proposed algorithm is able to achieve more than 90 percent of the optimum network performance with much lower overhead and complexity.

Vehicular networks are continually gaining popularity, owing to the evolution of the Internet of things, by means of rapid communication in IP-based networks. Vehicles are being fitted with sensory devices to gain inputs from the external environment for information processing. Numerous applications of vehicular networks depend on the use of communication networks. The security and privacy of data communication are significant challenges, particularly in wireless applications, for example, the Internet of connected vehicles. When an official fleet of vehicles (government or military) begins its journey, the vehicles need to communicate with one another to share sensitive information. The security of such a fleet is maintained in various security layers, each of which coordinates and communicates with the others, but avoids disclosing sensitive information of higher security layers to lower security layers. No such access control model exists that can enforce the authority of security officials in layers. We propose a novel security and privacy based access control (SPBAC) model for the Internet of connected vehicles, which allows security officials to access information in combination with permissions and roles, instead of roles only, for officials traveling in vehicles belonging to the same fleet. Vehicle-to-vehicle communication is performed with the aid of onboard unit sensory devices. The vehicles can also communicate through wireless technology, namely WiFi and cellular communications (4G/5G). The SPBAC model provides communication among security layers in a secure, private, and efficient manner compared to other state-of-the-art algorithms. The SPBAC model is demonstrated here using mathematical modeling along with implementation examples.

Faced with constant increasingly complicated communication network architecture issues and blossoming traffic demand over wireless systems, it is still insufficient for dynamic spectrum resource allocation in the fifth generation (5G) networks if cognitive radio (CR) technology lacks intelligence. For an efficient real-time process, a distributed cognitive cellular network is proposed in this article, which integrates artificial intelligence and CR technology into a sophisticated multi-agent system (MAS). It is a novel paradigm for 5G cellular communication networks. Balancing the resource allocation among primary users, secondary users, and base stations is of fundamental importance for dynamic time-frequency-space resource allocation to improve the utilization of the spectrum resources in the cognitive cellular network. We introduce a four-layer distributed networking framework and establish a hierarchical MAS model. Furthermore, we expound the key methods and technologies and evaluate the effectiveness through numerical simulations. Finally, challenges and open issues are discussed.

Device-to-Device (D2D) communication is a promising take over in cellular communication. Due to its advantages it gains significance in the industrial standardization along with academic researchers. The concept of two tier network can be evolved to enlighten the cellular communication. Making each cellular user as transmission relays it would form a massive D2D network resulting in increased offloading of cellular traffic. The scope of D2D also extends to mobile cloud computing, proximity applications, social network content distribution and so on. It has been proved to be the best solution for energy efficient, spectral efficient technology which meets the capacity demand. However, the D2D scheme have practical challenges which needs to be met in order to keep its place primary in the next generation wireless communication. One of the major challenges which has to be addressed and resolved is resource allocation. In this paper various resource allocation scheme for D2D networks in cellular network are discussed. Each of the resource allocation with its signal to interference ratio performance with the other and the sum-data rate of each system is compared. D2D assisted Cognitive radio networks (Ahmad et al. in IET Commun 12(10): 1207–1214, 2008) can be developed to utilise the spectrum opportunistically for next generation communication systems.

Enabling high-rate, low-latency and ultra-reliable wireless communications between UAVs and their associated ground pilots/users is of paramount importance to realize their large-scale usage in the future. To achieve this goal, cellular- connected UAV, whereby UAVs for various applications are integrated into the cellular network as new aerial users, is a promising technology that has drawn significant attention recently. Compared to conventional cellular communication with terrestrial users, cellular-connected UAV communication possesses substantially different characteristics that present new research challenges as well as opportunities. In this article, we provide an overview of this emerging technology, by first discussing its potential benefits, unique communication and spectrum requirements, as well as new design considerations. We then introduce promising technologies to enable the future generation of 3D heterogeneous wireless networks with coexisting aerial and ground users. Last, we present simulation results to corroborate our discussions and highlight key directions for future research.

I welcome you to the first issue of the IEEE Communications Surveys and Tutorials in 2019. This issue includes 35 papers covering different aspects of communication networks. In particular, these articles survey and tutor various issues in “5G Networks,” “Wireless and Cellular Communications,” “Software Defined Networks and NFV,” “Internet Technologies and Multimedia Communications,” “Network Security: Classic Networks,” “Network Security: Emerging Networks” and “Miscellaneous.” There are three papers in the miscellaneous category that survey the issues in Power Line Communications, Network Verification and Testing, and Quantum Computing. A brief account for each of these papers is given below.

The evolution from conventional to smart grids over the last decades has obliged the grid to be prone to challenges by means of secure and reliable operation. One of the most important facts about smart grids is the communication infrastructure, which is a key factor while maintaining the secure operation of smart grid systems. This paper will focus on the communication techniques used in smart grids and their applications. Communication techniques have a crucial importance to ensure the efficient, flexible, reliable, sustainable, secure and robust features of the smart grids. Long term benefits and challenges of the smart grid communication techniques are elaborated thoroughly. Quantitative and qualitative features of the communication techniques are classified. Existing communication techniques such as ZigBee, WLAN, cellular communication, Power Line Communication (PLC) are compared within the standards and protocols. With the extensive integration of distributed energy resource (DER)s to the smart grid, the communication network infrastructure used in these resources are investigated. Moreover, the future oriented techniques (FoT) are presented for consideration in smart grid applications.

Recently, the vehicular ad hoc network (VANET) has attracted the attention of researchers with the development of the internet of things (IoT) and the intelligent transport system (ITS). One of the major application scenarios of the fifth generation wireless communication is massive machine type communication (mMTC). In order to aggregate the data recorded by machines, information packets need to be delivered to bureaus in the network. However, some packets are not very urgent and they don't have to be transferred by the cellular communication due to the fact that the spectrum source is scarce. With the increasing number of vehicles and the increasing computing power of on board units (OBUs), vehicle-to-vehicle (V2V) communications are better to deliver data packets. In order to transfer the packets effectively, it is important to find a reliable vehicular communication route. As the topology and the vehicles velocity change much more rapidly, the existing routing algorithms in other kinds of ad hoc networks are not suitable for the VANET. In this paper, we propose a vehicular routing algorithm based on graph theory. We consider the network situations more comprehensively and the simulation results show that the algorithm proposed is superior to the traditional routing algorithm.

Cellular communications have been regarded as promising approaches to deliver high-broadband communication links for Unmanned Aerial Vehicles (UAVs), which have been widely deployed to conduct various missions, e.g. precision agriculture, forest monitoring and border patrol. However, the unique features of aerial UAVs including high-altitude manipulation, three-dimension (3D) mobility, and rapid velocity changes, pose challenging issues to realize reliable cellular-enabled UAV communications, especially with the severe inter-cell interference generated by UAVs. To deal with this issue, we propose a novel position-based robust beamforming algorithm through complementarily integrating the navigation information and wireless channel information to improve the performance of cellular-enabled UAV communications. Specifically, in order to achieve the optimal beam weight vector, the navigation information of the UAV system is innovatively exploited to predict the changes of Direction-of-arrival (DoA) angle. To fight against the high mobility of UAV operations, an optimization problem is formed by considering the tapered surface of DoA angle and solved to correct the inherent position error. Comprehensive simulation experiments are conducted and the results show that the proposed robust beamforming algorithm could achieve over 90% DoA estimation error reduction and up to 14dB SINR gain compared with five benchmark beamforming algorithms, including Linearly Constrained Minimum Variance (LCMV), Position-based beamforming, Diagonal Loading (DL), Robust Capon Beamforming (RCB) and Robust LCMV algorithm.

The energy efficiency for wireless communication technology standard is very important for the current and the future generation ones. Noting that the energy consumption in communication systems is constantly increasing due to the exponential number of subscribers and high data services demand. In this regard, it becomes necessary to quantify this energy consumption with respect to the communication technology standard at the site. This article presents an evaluation of the factual quantifications methods for the energy consumption of transmission nodes in cellular communications systems. The data collection was obtained on three types of communication technology standards namely second generation (2G), 3G, 4G and their combination using the direct and indirect (the utility records) methods power measurement on the field installation of a mobile telephone operator in Togo. These data have undergone a preprocessing in the Microsoft Excel software (version 2019), then sent in the Matlab software (Matlab R2020b) for further analysis. The results showed that the energy consumption observed at the site is around 124 kWh, 254, kWh and 362 kWh on monthly average respectively for 2G, 2G/3G, and 2G/3G/4G typology used. It further indicated that when more communication standards are used on a given site, its power consumption is much more increasing. The power profile distribution has been investigated, and the analysis revealed that the normal distribution closely fitted the data. However, more parameters related to the number of utilised channels and climatic conditions need to be considered in future research works.

Radio maps can be used for source localization, link performance prediction, and wireless relay planning. This paper studies an air-to-ground radio map learning problem to predict the channel gain between a ground terminal and a low altitude unmanned aerial vehicle (UAV). The challenge is the insufficient measurement samples under the high dimensionality of the radio map, where both the transmitter and the receiver have full spatial degrees of freedom. Classical methods, such as k-nearest neighbor (KNN) and Kriging, may fail due to insufficient data. In this paper, a multi-degree channel model is proposed to fit low altitude air-to-ground propagation scenario. To address the high dimensionality issue, a hidden multi-class virtual obstacle model is developed, and a corresponding obstacle map is estimated from a small set of training data. Our numerical results confirm that the proposed model and the learning algorithm can significantly increase the prediction accuracy. When the constructed radio map applied to received signal strength (RSS) based source localization in a cellular communication scenario, a sub-20-meter accuracy is achieved, substantially better than the baseline model-based localization method.

Because of the significant development in demand for mobile communications, there has been a lot of study into making optimal use of the limited spectrum available for cellular communications. The authors propose a novel call admission control mechanism, DCAS (Dynamic Channel Allocation Scheme), in this work. The number of guard channel(s) is automatically modified in this new method based on the average handoff blocking rate observed over a given period of time. The handoff blocking rate is kept below the set limit, and the new call blocking rate is kept to a minimum. Simulation of nodes is used to evaluate the DCAS's performance. The DCAS method surpasses the Static Channel Allocation Scheme by setting a strict limitation on the likelihood of handoff rejection. The suggested approach provides the best results by optimizing resource consumption and dynamically adapting to changing traffic circumstances.

In the present world, energy consumption is increasing day by day, and the primary source of energy is fossil-based resources, which will dwindle shortly. A new concept called “Energy Internet” (EI) has recently been introduced to deal with these challenges. The EI vision tends to overcome some critical problems, such as improving sustainable and eco-friendly energy sources, new models for hybrid energy sources, more secure and effective energy management, and control systems. Wired and wireless communication technologies, such as ZigBee, WiMAX, cognitive radio, cellular communications, and the software-defined network (SDN), which are managed via the network system, are applied in the EI system to carry out monitoring, controlling, and management transactions in real time.One of the most recent communication technologies is the Internet of Things (IoT) that has provided the development of numerous different communication protocols. The IoT can be exploited to ensure communication between devices employing dissimilar data types. Moreover, in order to present a communication platform in both machine-to-machine (M2M) and human-to-machine (H2M) environments, IoT technologies utilize several communication mediums, protocols, and layer architectures. Charging demands differ among different types of electric vehicles and are influenced by the charging location. Random variables, such as technical characteristics and drive patterns, are taken into account to estimate the electric vehicles’ charging demand over time. The optimal location of charging stations also plays a critical role. The time-of-use (ToU) price is applied to influence the charging behavior of electric vehicles (EV) owners so that the charging demand can be reduced during peak hours and shifted to the off-peak hours. Due to ToU, the overall power load can be cut down.The chapter begins with a brief overview of the process of power delivery from generation site to load center, the role of demand side management and the challenges and opportunities provided by electric vehicles to the grid. Subsequently, the fundamentals of electric vehicles have been discussed along with an extensive coverage of various practices associated with information sharing and energy management in plug-in hybrid electric vehicles using vehicle-to-grid technology. The Internet of Energy is also discussed along with the process of information flow and the various communication technologies. Lastly, a hypothetical analysis is shown to reflect the impact of exchange of information and energy between the vehicle and the grid is discussed for a city with significant number of electric vehicles.

Due to the flexible deployment and low cost of unmanned aerial vehicle (UAV), the integration of UAV and wireless cellular networks is widely regarded as a promising technology to enhance the performance of wireless cellular communications. This paper considers a UAV-aided wireless cellular communication system with multiple adjacent ground users (GUs), where the primary mission of UAV is to collect data from all of the GUs. We take the GUs as the topological nodes and combine their communication ranges to construct a ground topology structure (GTS), with the purpose of designing a reasonable trajectory for the UAV to execute the data collection tasks, while ensuring the fairness of transmission among all of GUs. In order to solve these problems, we utilize parallel projection algorithm onto homogeneous and heterogeneous GTS respectively to obtain a group of waypoints which construct the UAV trajectory, we formulate the fairness of data collection as a min-max problem. Finally, simulation experiments show the trajectory design results of the homogeneous and heterogeneous GTS respectively. Numerical results further vaildate the effectiveness of our proposed algorithms.

This chapter incorporates the radio channel into the resource allocation formulations presented in the previous chapters in order to make the aforesaid approaches of resource assignment more pragmatic. It leverages the Shannon bound to model the channel with consideration of Modulation and Coding Scheme (MCS) as it appears in the Long Term Evolution (LTE) technology. The chapter uses a simple regression of the parameters to model the channel according to the MCS whose level depends on the signal-to-noise ratio (SNR). This chapter moves the resource allocation presented in the previous chapters from the realm of wired networks to that of the wireless cellular communications systems in which the channel conditions directly speak to the amount of resources to be assigned to any particular node. The chapter portrays the impact of channel on the assigned resources such that two applications with identical QoS requirements may in practice need significantly different resources.

As more and more advanced wireless technologies are incorporated into vehicles, there is a need to refine the test methods used for assessing the performance. Traditional test setups for multiple-input multiple-output (MIMO) communication systems have been developed for relatively small devices such as handsets and tablets. At the same time, there is a desire to replace vehicular field tests with lab testing, for more efficient and accurate testing. This paper evaluates over-the-air verification methods for MIMO communication systems, which may incorporate vehicle-sized antenna systems and that can be implemented in a lab. Different methods are compared by means of a round robin campaign. The results from the campaign indicate that performance assessment representative to real-world operation can be achieved.

This work evaluates the sum rate performance for dual user with full duplex co-operative non-orthogonal multiple access (FD-CNOMA) over Weibull fading channel environment. For this, we derived closed form expressions for sum-rate in various scenario in downlink and uplink both. One user always acts as decode and forward full duplex relay to help far users in each scenario. In the first scenario, no direct link exists between base station (BS) and far user. In second scenario, direct link exists between BS and far user. The main investigation is to study the effect of fading parameters in different channel condition on sum-rate performance. Since, Weibull Distribution (WD) has an advantage to model different fading condition using varying parameter it is more suitable to study impact of fading condition on different wireless techniques for next generation mobile cellular communication. Therefore, WD is used in this study for sum rate performance evaluation with derived expressions. Finally, simulations were conducted on MATLAB to evaluate the system performance under different fading parameters of Weibull fading channels .

In this paper proposed three modifications to the monitoring system of the overhead lines, insulation state and substations based on sensors installed on supports and insulators. The sensors operate on the principle of capacitive coupling with an insulating structure. Differences between the system modifications in the information present options: light indication for control when bypassing lines and substations and changing graphics on the computer (smartphone) screen when receiving data in real time from sensors using cellular communication. The principle of operation and functional diagrams of the system with results of tests and experiments with manufactured product samples in laboratory and field conditions are presented.

In recent years, telecommunication technologies have witnessed exponential growth, especially in the cellular communications and wireless sensor networks segment. To meet the demand of increasing transmission capacity, improving the signal-to-noise ratio of cellular communication channels and expanding to the operating band of the equipment are necessary. For example, when the fourth generation (4G) standard was designed and deployed, several new frequency bands were added. The expansion of the operating band poses a huge challenge, especially in the low-frequency band, because of the large bandwidth. It is difficult to design a mobile device with one or more multi-standard antennas. A reconfigurable antenna can be considered as one of the key elements in future wireless communication transceivers. The advantage of using a reconfigurable antenna is the ability to operate in multiple bands, where the total antenna volume can be reused, thus enabling the overall size to be reduced. Modern wireless communication systems relying on multi-band reconfigurable antennas are becoming more popular for their ability to serve multiple standards. Devices using a single compact antenna allow a reduction in the dimensions of the device and more space to integrate other electronic components. Besides, in wireless sensor networks application, a directional reconfigurable antenna has the potential to reduce transmission collisions, increase communications distance, and optimize consumption, when compared with a traditional omnidirectional antenna.

Future wireless cellular networks must support both enhanced mobile broadband (eMBB) and ultra reliable low latency communication (URLLC) to manage heterogeneous data traffic for emerging wireless services. To achieve this goal, a promising technique is to enable flexible frame structure by dynamically changing the data frame's numerology according to the channel information as well as traffic quality of service requirements. However, due to nonorthogonal subcarriers, this technique can result in an interference, known as inter numerology interference (INI), thus, degrading the network performance. In this work, a novel framework is proposed to analyze the INI in the uplink cellular communications. In particular, a closed form expression is derived for the INI power in the uplink with a flexible frame structure, and a new resource allocation problem is formulated to maximize the network spectral efficiency (SE) by jointly optimizing the power allocation and numerology selection in a multi user uplink scenario. The simulation results validate the derived theoretical INI analyses and provide guidelines for power allocation and numerology selection., Comment: In Proc. of the 2021 IEEE 93rd Vehicular Technology Conference: VTC2021-Spring

This paper addresses millimeter-wave propagation estimation for urban macro-cellular and urban micro-cellular scenarios at 28 GHz, 38 GHz, 58 GHz, and 73 GHz, and observes the corresponding propagation characteristics indicating the path loss for UMa and UMi scenarios using 3GPP proposed path loss models, in both line-of-sight and non-line-of-sight environments, for the efficient deployment of 5G cellular communication networks. The purpose of this work is to characterize the mmWave spectrum depending on the distance for the urban environment to determine the optimal mmWave frequency band according to the transmitter-receiver separation distance to ensure the necessary connectivity and data rate.

The controversy and argument on the usefulness of the physical layer (PHY) academic research for wireless communications are long-standing since the cellular communication paradigm gets to its maturity. In particular, researchers suspect that the performance improvement in cellular communications is primarily attributable to the increases in telecommunication infrastructure and radio spectrum instead of the PHY academic research, whereas concrete evidence is lacking. To respond to this controversy from an objective perspective, we employ econometric approaches to quantify the contributions of the PHY academic research and other performance determinants. Through empirical analysis and the quantitative evidence obtained, albeit preliminary, we shed light on the following issues: 1) what determines the cross-national differences in cellular network performance; 2) to what extent the PHY academic research and other factors affect cellular network performance; 3) what suggestions we can obtain from the data analysis for the stakeholders of the PHY research.

A topic of interest to researchers and engineers alike is the potential of using Unmanned Aerial Vehicle (UAV) as a relay base station in cellular communication. The driving factor behind its use is the innovations in wireless communication technologies, in particular the upcoming 5G network. The super-low latency and enormous bandwidth availability in millimeterwave triggers the usefulness of UAV deployment in Mobile Ad-Hoc Networks (MANET). This paper is a brief experimental review on ray-tracing simulation for a UAV-aided 5G network. The objective of this paper is to assess the usage of UAV in next-generation wireless networks, i.e., deploying UAV as a relay using millimeter-wave concurrently in backhaul and access links. Ray-tracing simulations are used to synthesise the coverage of UAV-aided base station (UAV) in three scenarios; i) UAV elevation, ii) UAV horizontal variation, and iii) UAV base station elevation and horizontal variation-simultaneously. In all three scenarios, the optimum placement of UAV for enhanced User (UE) coverage is spotlighted. In addition, the significance of the amplification factor in the relay path is illustrated. It is believed that the findings reached in this paper are of great value to 5G ad-hoc network planners.

In the notion of communication system resource provision specifically, beam-forming is a concept of proficient utilization of the power of transmission. Network densification and massive MIMO allows us to control the power efficiency and can be effectively distributed among different users by reducing cost. We presented a practical scenario for the performance of massive MIMO and multi-small cell system to analyze the overall performance of the system. Our work is based on the resource allocation with optimal structural constraints to maintain the cost effectiveness while considering economic implications. The base stations located far away from the users receive attenuated signals and give rise to path loss, whereas the problems of inter cell interference also arise due to transmission from a base station to others cells. The performance of the cellular system can be enhanced with the combination of massive Mimo and small cells, where we simulate and also provide an analysis on practical system with optimal and low complexity beam-forming. The proposed scenario illustrates a structure with an optimal linear transmit beamforming regarding an efficient number of parameters to not lose optimality, which is extendable to designate any specific cellular network in consideration. Our approach exploited schemes with low complexity that are facilitating in complete solution formation, and tested them in various and all possible cases and scenarios.

This paper considers a device-to-device (D2D) cellular communication network with the wireless communication link among the devices and the base station (BS) modeled by the Rician fading and the wireless communication link between the devices modeled by Nakagami-m fading distribution. The devices and the BSs are assumed to be placed randomly as independent Poisson point processes with the devices experiencing interference from both D2D users and the cellular users. Using the techniques of stochastic geometry, series form expressions of the coverage probability of the cellular users are derived for the underlying interference-limited D2D cellular network. Furthermore, the optimal coverage values that maximize the energy efficiency of the network are also obtained analytically. The effect of the Rician factor and other system parameters on the performance of the system is studied by numerical results. The study of the variations of the optimal coverage analysis with the system parameters presented in this paper gives an insight into the design of cellular D2D communication networks.

The recent advances in wireless technologies made it possible to inter connect every device wirelessly to the Internet, which is called as Internet of Things (IoT). 5G cellular communication research community has been compelled to design solutions for the IoT along with conventional data communications and voice/video over IP networks. The IoT plays a critical role in the modern society with smart cities, smart power grids and other applications. These applications demand ultra low power and low cost solutions. To meet such diversified requirements, novel physical layer need to be designed. In this paper, a novel accessing technique with the LTE procedures defined by 3GPP has been used to cater the needs of IoT devices generated random traffic. A new system with Offset Quadrature Amplitude Modulation (OQAM) and bi-orthogonal frequency division multiplexing (BFDM) is simulated using Matlab Software along with BFDM QAM and LTE based OFDM. In this paper, the performance of BFDM-OQAM system is compared with OFDM and BFDM QAM systems under Line of Sight fading conditions such as Rural Line of Sight (RLOS), Highway Line of Sight (HLOS), and Urban Approaching Line Of Sight (UALOS).