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The efficiency of cellular communication systems is hampered by cyclones. Network operator authenticated network blind spots, generated after cellular BTS destruction, were successfully recovered u...

Future cellular communication systems might be based on millimeter wave frequencies. So, there is a need to design and deploy antennas which operate in the millimeter wave spectrum integrated in mo...

Gelecek nesil kablosuz iletişim sistemlerinde, spektrum doluluk problemi nedeni ile yüksek spektrum verimliliğinde (SE) hizmet sunulması en önemli hedefler arasındadır. Bu düşünce ile öncelikle bu tezde, masif MIMO haberleşme sistemlerinde, yüksek SE kazancına odaklanılmıştır. Bu kapsamda, araştırmacılara yol gösterici olması adına, Maksimum Oran Birleştirme (MRC) veya Sıfıra Zorlama (ZF) kullanarak, sabit veya farklı uzunluktaki pilot dizisi ile Zaman Bölmeli Çiftleme (TDD) veya Frekans Bölmeli Çiftleme (FDD) modu kombinasyonlarıyla yüksek SE başarımı sunabilen farklı senaryo analizleri sunulmuştur. Özellikle, masif MIMO sistemlerindeki baz istasyonundaki (BS) antenlerinin sayısı ve pilot yeniden kullanım faktörü ile birlikte ideal kullanıcı terminali sayısının (U), SE bazında etkin kaynak tahsisi açısından önemli olduğu anlaşılmıştır. Bu bağlamda, tezin ilerleyen kısımlarında, üç girişim seviyelerine dayalı olarak, sinyal-parazit-ve-gürültü oranları (SINR) ile birlikte kapalı form SE denklemleri elde edilmiştir. BS'deki anten sayısının bir fonksiyonu olarak, çoklu pilot yeniden kullanım faktörleri ile MRC ve ZF gibi çeşitli işleme şemaları dikkate alınarak benzetimler gerçekleştirilmiştir. Sonuçlardan, U'nun işleme şemalarına göre değişiklik gösterdiği anlaşılmıştır. Genel olarak, bu sonuçlar, çok hücreli sistemlerde bu tezde elde edilen U dikkate alındığında, SE'den azami seviyede yararlanılabilecek olması ile literatüre katkı olarak sunulmuştur. Böylelikle, heterojen ağlarda SE açısından ideal U sayısına ulaşan bir hücreye dâhil olmak isteyen kullanıcının başka bir ağa yönlendirilmesi için ağ değiştirme algoritmalarına girdi verisi sunulmuştur. Ayrıca, bu tez çalışmasında masif MIMO sistemlerinde enerji verimliliğini (EE) en üst düzeye çıkarmak için yenilikçi bir pilot güç tahsisi algoritması önerilmiştir. Algoritma, ilgili SINR değerlerini polarize ederek pilot güçlerini optimize etmektedir. Optimize edilen bu güç değerleri sayesinde, toplam harcanan güç bütçesinin daha da düşürüldüğü gözlemlenmiştir. Algoritmanın başarımı, benzetim sisteminin kümülatif dağılım fonksiyonu (CDF)-EE çıktıları kullanılarak ölçülmüştür. Ayrıca, aynı benzetim ortamları altındaki başarımları karşılaştırmak için eşit pilot güç tahsisi (EPPA) ve su doldurma pilot güç tahsisi (WF-PPA) şemaları da uygulanmış ve önerilen sezgisel yaklaşımımızın EPPA ve WF-PPA yöntemlerinden daha üstün olduğu kanıtlanmıştır. In the next generation wireless communication systems, providing high spectrum efficiency (SE) service is among the most important targets due to the spectrum occupancy problem. Hereby, this thesis focuses on high SE gain in massive MIMO communication systems. In this context, different scenario analyzes that provide high SE performance using Maximum Ratio Combining (MRC) or Zero Forcing (ZF) with either a fixed or different length pilot sequence with Time Division Duplex (TDD) or Frequency Division Duplex (FDD) mode combinations are presented to guide the researchers. In particular, it has been understood that the number of antennas in the base station (BS) and the pilot reuse factor in massive MIMO systems, as well as the ideal number of user terminals (U), are important for efficient resource allocation on the basis of SE. Within this scope, closed-form SE equations with signal-to-noise-and-noise ratios (SINR) based on three interference levels are obtained later in the thesis. Simulations are performed considering multiple pilot reuse factors and various processing schemes such as MRC and ZF as a function of the number of antennas in the BS. From the results, it was understood that U varies according to the processing schemes. In general, these results are presented as a contribution to the literature, with the maximum utilization of SE in multicellular systems, considering the U obtained in this thesis. Thus, in heterogeneous networks, the input data is presented to the network switching algorithms for routing the user to another network that wants to be included in a cell that reaches the ideal U number in terms of SE. Also, in this thesis, a novel pilot power allocation algorithm is proposed to maximize energy efficiency (EE) in massive MIMO systems. The algorithm optimizes the pilot powers by polarizing the corresponding SINR values. It has been observed that the total power budget is reduced even more thanks to these optimized power values. The performance of the algorithm was measured using the cumulative distribution function (CDF)-EE outputs of the simulation system. In addition, equal pilot power allocation (EPPA) and water fill pilot power allocation (WF-PPA) schemes have also been applied to compare performances under the same simulation environments, and our proposed heuristic approach has proven to be superior to EPPA and WF-PPA methods.

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

Recently, low-density parity-check (LDPC) codes have been adopted in Advanced Television Systems Committee 3.0 and 3rd Generation Partnership Project 5G standards. In this paper, we present their structures in detail. They are delicately designed, based on the structures of quasi-cyclic LDPC codes and multi-edge type LDPC codes. The differences in their base matrices and parity-check matrices used in both standards are highlighted from the viewpoint of the distinction between broadcasting and cellular communication systems. Numerical results show that they are very competitive in their respective areas.

To reinforce the coverage and QoS (quality of service) of on-ground cellular communication system, unmanned aerial vehicles which are carrying small cells are deployed in some emergency and disaster areas. Although ASCs (aerial small cells) can provide a higher probability of LoS (line-of-sight) transmission, the wireless backhaul link will bring extra interference to the whole system if not well designed. Therefore, in this paper, we study the backhaul scheme for UAV-assist cellular network. We first analyze the interference environments of UAV-assist cellular network considering the IBOG (In-Band to On-Ground), OBOG (Out-of-Band to On-Ground) and IBTU (In-Band to Tethered-UAV) backhauling mode, and give the descriptions of the performance metrics for each mode. Then, the considered problem is formulated as an optimization of achievable rate. We derive the optimal solutions for the involved three backhauling modes for ASCs respectively, and closed-form optimal value for each mode is acquired with proof. We also give a pseudo-code form of our proposed optimal access/backhaul spectrum allocation algorithm. The simulation results indicate that the proposed scheme can deliver a significant gain, while IBTU performs best among proposed backhauling modes.

In this paper, we started from the normal cellular communication system and studied a two-hop multi-relay DF cognitive relay network system. Under the interference from the primary user and an eavesdropper, which could wiretap the information while transferring messages, and all channels experiencing Nakagami–m fading with different parameters. Considering the existence of direct links, we employed the selection combing technique at the receive nodes. After deriving the secrecy outage probability, we compared the numerical results with simulations to verify the veracity of our theoretical results. Besides, we observed the variety of secrecy outage probability under different parameters and offered some advice about the design and optimization of cognitive relay network.

Mobile ad-hoc networks (MANETs) presenting a distinct and infrastructure free network which are group of wireless nodes functioning with self-driven and self-routing principle. Ad-hoc networks, a new set of communication platform, experimented for enabling effective communication during cyclonic disaster and calamities. Dynamic mobility system is an emergent evolution for different type of rescue operations. The Ad-hoc networks can be set up for a reliable communication among provisionally assembled user terminals without depending on the cellular communication system. So this study is prepared on scalability and geographical routing protocols employed for the communication in rescue operations for the fishing boats in coastal bed of odisha during cyclonic disaster or in an emergency communication situation.

This paper studies the adaptive mode selection and power allocation for D2D underlay cellular communication systems with the consideration of dynamic fading channel state information (CSI). It aims to maximize the throughput of D2D users while guaranteeing the required quality of service (QoS) of cellular networks. To solve this problem, the expression of throughput for D2D users under dynamic CSI is firstly derived. Subsequently, an adaptive mode selection and power allocation scheduling are obtained. Numerical simulations are provided to validate the analysis and throughput enhancement.

Global ısınmanın yadsınamaz etkileri, toplumun gün geçtikçe sürdürülebilirlik konusunda farkındalığını artırmakta ve hükümetlerin yeşil enerji politikalarını desteklemesini sağlamaktadır. Öte yandan mobil ağ teknolojileri için önerilen çözümler sürdürülebilirlik açısından yetersiz kalmaktadır. Bunun yanında, gelecek nesil radyo erişim ağlarının yüksek veri ihtiyacı mobil servis sağlayıcılarının maliyetlerini arttırmakta ve bu sağlayıcıları ekonomik çözüm arayışına itmektedir. Bu tezde, tüm bu ihtiyaçlara karşılık vermek için, güneş panellerinin alternatif enerji olarak kullanıldığı radyo erişim ağlarının enerji ve maliyet optimizasyonu problemlerine odaklanıldı. Bu problemler, üçüncü nesil mobil haberleşme teknolojilerindeki solar enerji beslemeli baz istasyonlarının kurulum ve operasyon aşamalarından, beşinci nesil merkezi mobil erişim ağlarındaki fonksiyon paylaştırma ve Ethernet üzerinden radyo yaklaşımlarıyla solar enerji kaynaklarının entegrasyonuna kadar geniş bir spektrumda yer almaktadır. Çözüm için önerilen mimariler nesillerine göre yenilikçi yaklaşımlar olup, mobil servis sağlayıcılarına enerji ve maliyet giderlerini azaltmaları için en uygun boyuttaki yenilenebilir enerji ekipmanlarını seçmelerini ve bunları işletmelerini sağlamaktadır. Bunun yanında çözümlerde gerçek güneş enerjisi verisi kullanılması ve birçok değişken koşulun test edilmesi, bu çözümlerin birbirinden farklı ağ ortamlarında kullanılmasına olanak vermektedir. Böylece, bu çözümler yenilenebilir enerji kaynaklarını kullanarak mobil ağlardaki enerji tüketimi ve karbon emisyon oranlarını azaltırken, bir yandan da servis sağlayıcıların karlarını arttırarak bu sistemlerin ekonomik uygulanabilirliğini sağlamaktadır. Due to the incontrovertible effects of global warming, society grows its sustainability awareness regularly, and governments start to change their energy policies to promote green energy sources. However, mobile network technologies have not been ready for new sustainable solutions. Besides, the high data demand in the next-generation radio access networks encourages mobile network operators to investigate cost-efficient solutions. Therefore, this thesis addresses the energy and cost optimization problems of a radio access network that uses the solar panels as an alternative energy source. We investigate several design problems from deployment and operation of solar-powered base stations in the third generation mobile communication networks to integrate the renewable energy sources into the function splitting, and Radio over Ethernet approaches in the fifth-generation centralized radio access networks. The proposed architectures are novel for their generations and offer remarkable guidance to the service providers to choose the proper size of renewable energy source equipment and how to operate this equipment to get the best energy and cost-efficiency. Besides, we provide both mixed-integer linear programming and heuristic solutions for different scales of problems. Also, we use real-world solar data and experiment with several instances to prove that our solutions can be implemented in the networks with different circumstances. Therefore, the operators can improve their profits and economic feasibility in their projected mobile communication networks while our proposed solutions reduce the energy consumptions and the carbon emission rates by promoting the use of renewable energy sources. 131

Quality of mobile system communication is significantly defined by completeness and reliability of information on a status of objects of radio-electronic means. In most cases, the probability of decline in quality increases with untimely response of field services to the existing back couplings of the control system and the analysis of parameters of quality. Modern objects of radio-electronic means are known to be difficult systems having technical intelligence. Therefore, when processing the arriving information on statuses from such objects there happen such situations when use of traditional methods brings to a row of difficulties in their analysis. It occurs for the reasons of insufficiency of prior information, multiparametricity, volume of computing character, a non-standard of situations, a subjective factor of operators. In this regard for processing of such information it is offered to use the theory of fuzzy sets. Parameters of monitoring in the system of mobile communication have been determined. Using the field power level as a key parameter is justified because the whole range of the related secondary parameters of communication quality on input of a receiving device depends on signal power of a communication system in a point of reception. The fuzzy production model has been developed. Each parameter is provided to a linguistic variable for which there is defined a term - set of values. The fuzzy production rules of the model are realized using Fuzzy Logic Toolbox of the software MATLAB on the basis of Mamdani's algorithm.

Applying propagation models with good accuracy is an essential issue for increasing the capacity and improving the coverage of cellular communication systems. This work presents an algorithm to calculate total diffraction losses for multiple obstacles objects using Epstein–Peterson approach. The proposed algorithmic procedure to model the diffracting can be integrated with other propagation mechanisms in ray-tracing for the prediction of received signal level in non-line-of-sight environments. This algorithm can be interpreted into software application to scan large areas with a reasonable simulation time.

The data on the use of solar photovoltaic plants (PVPs) for providing a reliable and guaranteed power supply to telecommunication systems and cellular communication systems in the conditions prevalent in Uzbekistan are given. The research-based structures developed by OOO MIR SOLAR and the selection of PVP elements ensuring their reliable operation are described. The main influencing factors are discussed, and the use of effective combinations of different types of panels (from monocrystalline and polycrystalline silicon) and a specially developed controller are considered.

The main purpose of the article is to answer the question about meeting the operational requirements of the railway through the GSM-R cellular communication system. The first part presents the basic features of the radio interface (subscriber access) to GSM-R. Next has been carried out an analysis of selected railway interoperability requirements of the CCS TSI. In the main part, the theory of telecommunications traffic was used to calculate the probability of call blocking in the area of generic cell in the network. The article ends with summaries and conclusions from the analysis.

Son yıllardaki akıllı-telefon, tablet ve akıllı saat gibi internete bağlı cihaz sayısındaki üstel artış ve Nesnelerin İnterneti (Internet of Things -IoT) kavramının da gelişmesiyle birlikte, yeni nesil telsiz ağların yoğun hücrelerden (dense networks) oluşması ve kitlesel iletişimi (massive connection) desteklemesi gerektiği kaçınılmaz olmuştur. Kitlesel makine tipi iletişim (massive Machine Type Communication -mMTC) olarak adlandırılan bu konsept 5G ve sonrası olarak bilinen yeni nesil telsiz ağların üç ana konseptinden biri olarak görülmektedir. Dik olmayan çoklu erişim (Non-orthogonal Multiple Access -NOMA), yüksek spektral verimlilik sağlaması ve kitlesel iletişime olanak sağlaması nedeniyle mMTC için en önemli adaylardan biri konumundadır. NOMA'da kullanıcılar aynı kaynak bloklarına (resource block) atanarak spektral verimliliğin arttırılması amaçlanmaktadır. En fazla ilgi çeken NOMA konsepti olan güç eksenli (power domain -PD) NOMA'da, kullanıcılar aynı kaynak bloklarını farklı güç paylaşım katsayıları ile paylaşırlar. PD-NOMA'da ki kullanıcılar arası girişim, ardışık girişim giderici (successive interference canceler -SIC) kullanılarak giderilir. NOMA'nın 5G ve sonrası ağları için önemli bir potansiyele sahiptir ve bu nedenle araştırmacıların oldukça fazla ilgisini çekmektedir. NOMA erişilebilir kapasite ve kesinti olasılığı açısından fazlasıyla araştırılmıştır/incelenmiştir. Fakat, bu çalışmalarda çoğunlukla, alıcıların hatasız SIC uyguladığı varsayılmıştır. Bu varsayım sönümlemeli kanallar göz önüne alındığında gerçekçi bir varsayım olmaktan çıkmaktadır. Bununla birlikte, NOMA erişilebilir kapasite ve kesinti olasılığı açısından fazlasıyla incelenmesine rağmen, bir diğer önemli kriter olan bit/sembol hata oranı göz ardı edilmiştir. NOMA hakkındaki bu endişeler bu tez çalışmasının ana motivasyon kaynağı olmuştur. Bu çalışmada, NOMA için hatalı SIC varlığında erişilebilir hız, kesinti olasılığı ve bit hata olasılığı açısından analizlerinin yapılması amaçlanmıştır. NOMA'nın bir diğer avantajı da diğer fiziksel seviye teknikleri ile beraber kullanılabilmesidir. Bu nedenle, aynı analizler, NOMA ile işbirlikli iletişimin ve uzaysal modülasyonun birlikte kullanıldığı durumlar için de genişletilmiştir.Tez çalışmasında ilk olarak geleneksel NOMA ağları (aşağı yönlü ve yukarı yönlü) hatalı SIC varlığında incelenmiştir. Üç önemli performans kriteri olan, erişilebilir hız, kesinti olasılığı ve bit hata olasılığı için tam ifadeler kapalı formda türetilmiştir. Elde edilen tüm analitik sonuçlar bilgisayar benzetimleri ile doğrulanmıştır.NOMA ve işbirlikli iletişimin beraber kullanıldığı ağlar araştırmacılar tarafından en fazla ilgi çeken konulardan biri olmuştur. Bu etkileşim üç ana konsepte incelenmektedir: 1) Daha iyi kanal kalitesine sahip NOMA kullanıcılarının daha kötü kanal kalitesine sahip kullanıcılar için röle olarak görev yaptığı, İşbirlikli-NOMA konsepti. 2) Ortamda bulunan rölelerin NOMA kullanıcılarıyla olan iletişime yardımcı olduğu, Röle-destekli/yardımlı-NOMA konsepti. 3) Geleneksel işbirlikli iletişimdeki spektral verimsizliğinin önüne geçmek için kullanılan, NOMA-destekli işbirlikli iletişim sistemleri (cooperative relaying systems -CRS) konsepti. Her üç konsept de hatalı SIC varlığında tüm performans kriterli açısından incelenmiştir ve sonuçlar bilgisayar benzetimleri ile doğrulanmıştır. İşbirlikli-NOMA sistemlerindeki hata yayılımının etkisini ortadan kaldırmak için, Eşik değer tabanlı seçmeli işbirlikli-NOMA (Threshold-base selective cooperative-NOMA – TBS-C-NOMA) sistemi önerilmiş ve önerilen TBS-C-NOMA'nın işbirlikli-NOMA'ya üstünlük sağladığı kanıtlanmıştır. TBS-C-NOMA tam çeşitleme derecesi sağlamaktadır. Geleneksel NOMA ağlarının BHO başarımdaki kaybın önüne geçmek için, uzaysal çoklu erişim (Spatial Multiple Access (SMA)) ve Uzay kaydırmalı Anahtarlama (Space Shift Keying SSK)-NOMA yapıları sırasıyla iki kullanıcılı ve çok kullanıcılı NOMA ağlarına alternatif olarak önerilmiştir. Önerilen her iki yöntem için de erişilebilir kapasite, kesinti olasılığı ve bit hata olasılığı ifadeleri kapalı-formda türetilmiştir. Sonuçlar bilgisayar benzetimleri ile doğrulanmıştır.Daha sonra, NOMA'nın kullanıldığı sitemler için detaylı benzetimler sunularak kapsamlı bir performans değerlendirmesi verilmiştir. NOMA erişilebilir kapasite ve kesinti başarımı açısından dikgen çoklu erişim tekniklerine (Orthogonal Multiple Access -OMA) üstünlük göstermesine rağmen kullanıcılar arası girişim sebebiyle bit hata başarımı açısından OMA kadar iyi performans gösterememektedir. Farklı performans kriterleri arasındaki bu ödünleşime (trade-off) dikkat çekilerek, NOMA sistemlerinin hedef güvenirlilik (target reliability) kriteri göz önünde bulundurularak tasarlanması gerektiği ortaya konmuştur. Sunulan detaylı benzetim sonuçları doğrultusunda, önerilen TBS-C-NOMA'nın C-NOMA'ya, SMA ve SSK-NOMA'nın da geleneksel NOMA sistemlerine üstünlük sağladığı gösterilmiştir. Bu bölümde son olarak, farklı performans kriterleri göz önüne alınarak, en iyi güç paylaşımının nasıl olması gerektiği tartışılmıştır.Son olarak, elde edilen tüm sonuçlar değerlendirilerek, tez gelecek çalışmalar hakkındaki görüşler, olası çalışma alanları ve zorluklar sunularak sonlandırılmıştır. In recent years, exponential increase in connected devices (i.e., smart-phones, tablets, watches etc.) to the internet and with the introduce of the Internet of Things (IoT), future radio networks (FRN) are keen to serve massive users in dense networks which is called as Massive Machine Type Communication (mMTC) -one of the three major concepts of 5G and beyond-. Non-orthogonal Multiple Access (NOMA) is seen a strong candidate for mMTC in FRN due to its high spectral efficiency and ability to support massive connections. In NOMA, users are assigned into same resource block to increase spectral efficiency and the most attracted scheme is power domain (PD)-NOMA where users share the same resource block with different power allocation coefficients. The interference mitigation in PD-NOMA is held by successive interference canceler (SIC). Due to its potential for 5G and beyond, NOMA has attracted tremendous attention from researchers where NOMA is widely investigated mostly in terms of achievable rate and outage probability. However, in those work mostly perfect SIC is assumed at the receivers which is not that reasonable assumption considering the fading channels. In addition, whereas numerous efforts have been devoted to investigating NOMA in terms of capacity and outage, one of the most important key performance indicators (KPIs): bit/symbol error rate (BER/SER) has not been regarded. These two major concerns about NOMA have initially motivated us to do this PhD research. This work aims to investigate three KPIs (capacity, outage and BER) of NOMA with imperfect SIC. Then, the same analysis is done for the interplays of NOMA with cooperative communication and spatial modulation (SM).Firstly, conventional NOMA (downlink and uplink) networks is analyzed under imperfect SIC and exact closed-from expressions for ergodic capacity (EC), outage probability (OP) and bit error probability (BEP) are derived over fading channels. All derived expressions are validated via computer simulations.The interplay between NOMA and cooperative communication is one of the most attracted NOMA related topics in the literature. This interplay is divided into three concepts: 1) cooperative-NOMA (C-NOMA) where strong NOMA users act as relays for weaker users to improve reliability of them. 2) relay-assisted/aided-NOMA where dedicated relays help source serving to NOMA users. 3) NOMA based cooperative relaying system (CRS) where NOMA is applied for different symbol of the destination to improve the inefficiency of device-to-device cooperative communication. All three concepts have been analysed in terms of the same performance metrics (i.e., EC, OP, BEP) under imperfect SIC and have been validated via Monte Carlo simulations. Then, threshold-based selective cooperative NOMA (TBS-C-NOMA) have been proposed to eliminate the effect of error propagation in C-NOMA and it is proved that TBS-C-NOMA outperforms C-NOMA and achieves full diversity order.In order to neutralize the decay in BER of conventional NOMA networks, the spatial multiple access (SMA) and Space Shift Keying (SSK)-NOMA have been introduced as alternatives to two users and multiple users multiple-input-multiple-output (MIMO)-NOMA networks. Closed form expressions of EC, OP and BEP have been derived for both systems and the derived expressions have been validated via computer simulations.Then, a comprehensive evaluation of NOMA involved systems is presented by extensive simulations. It is proved that NOMA outperforms orthogonal multiple access (OMA) techniques in terms of EC and OP. However, due to the inter-user interference (IUI), NOMA cannot compete with OMA networks. Thus, the trade-off between capacity and reliability of NOMA networks is emphasized and it is revealed that NOMA design should be handled considering the target reliability of networks. In addition, the performance improvement of the proposed TBS-C-NOMA scheme are presented compared to C-NOMA schemes. Furthermore, based on the extensive simulation results, it is proved that the proposed SMA and SSK-NOMA systems outperform their NOMA counterparts in terms of all three performance metrics (i.e,, EC, OP and BER). Moreover, the effect of power allocation on the performances of NOMA involved systems are investigated and the optimum power allocation in terms of three KPIs is discussed.Finally, all results are discussed and the thesis is concluded with the opportunities, challenges and the insights for future researches. 209

Handover is one of the facilities in the cellular communication system to ensure the continuity of communication when the customer moves from one cell to another cell. In this research will be analyzed on the optimization of soft handover performance of three eNB on LTE network with threshold method. Network performance parameters observed were RSRP (Reference Signal Received Power) and number of handover. The simulation result shows that with thershold value change we get RSRP value which is more optimal for the three eNB, each of three eNB are distanced by 8000 m. When the thershold value is - 113 dBm at a speed of 15 m / s, the RSRP value is very much greater than the threshold value so can be to minimize the number of handovers. Also it is found that the speed effect on the number of handover, where the greater the speed then the number of handover will be even greater.

Fluency in a common language allows individuals to convey information and carry out complex activities that otherwise would be difficult or even impossible without the benefit of shared communication. Cyclic (di)nucleotides have recently been recognized as such an accessible language understood by both microbe and the host, ever since remarkable progresses have revealed the molecular details of these nucleotide second messengers used in cellular communication systems. Though undergoing separate evolutionary pathways in prokaryotes and eukaryotes, cyclic (di)nucleotides enable microbes to influence host cells immediately and fiercely by modulating a variety of cellular activities. Here we highlight recent insights in cyclic (di)nucleotides and focus on the balancing of these indispensable signaling molecules by synthases and phosphodiesterases.

This paper presents 28 GHz wideband propagation channel characteristics for millimeter wave (mmWave) urban cellular communication systems. The mmWave spectrum is considered as a key-enabling feature of 5G cellular communication systems to provide an enormous capacity increment; however, mmWave channel models are lacking today. The paper compares measurements conducted with a spherical scanning 28 GHz channel sounder system in the urban street-canyon environments of Daejeon, Korea and NYU campus, Manhattan, with ray-tracing simulations made for the same areas. Since such scanning measurements are very costly and time-intensive, only a relatively small number of channel samples can be obtained. The measurements are thus used to quantify the accuracy of a ray-tracer; the ray-tracer is subsequently used to obtain a large number of channel samples to fill gaps in the measurements. A set of mmWave radio propagation parameters is presented based on both the measurement results and ray-tracing, and the corresponding channel models following the 3GPP spatial channel model (SCM) methodology are also described.

Biofilm formation in healthcare is an issue of considerable concern, as it results in increased morbidity and mortality, imposing a significant financial burden on the healthcare system. Biofilms are highly resistant to conventional antimicrobial therapies and lead to persistent infections. Hence, there is a high demand for novel strategies other than conventional antibiotic therapies to control biofilm-based infections. There are two approaches which have been employed so far to control biofilm formation in healthcare settings: one is the development of biofilm inhibitors based on the understanding of the molecular mechanism of biofilm formation, and the other is to modify the biomaterials which are used in medical devices to prevent biofilm formation. This review will focus on the recent advances in anti-biofilm approaches by interrupting the quorum-sensing cellular communication system and the multidrug efflux pumps which play an important role in biofilm formation. Research efforts directed towards these promising strategies could eventually lead to the development of better anti-biofilm therapies than the conventional treatments.

The use of existing measurements from wireless communication or navigation systems for opportunistic sensing of the environment is an emerging field of great potential. In the last two decades, the use of physical measurements from signals in GPS system, in cellular communication system and in communication satellites has shown the ability to monitor moisture, rain and other atmospheric phenomena. In each technology, the corresponding virtual sensor has to be characterized based on the physics which relates the available measurements to the phenomenon of interest. The major opportunity, however, is the availability of numerous numbers of such virtual sensors. In particular, when using near-ground wireless communication technologies, the number of such virtual sensors can be huge, and their use becomes a typical IoT application. Based on our experience and expertise with using measurements of the signal levels in backhaul communication microwave networks of cellular systems, in this paper we will focus on the IoT framing of this technology and will discuss specific challenges and opportunities.

The seismic resilience of civil infrastructure systems has a direct effect on the resilience of communities. These systems provide communities with essential services, including potable water and electric power. It is, however, not only important to account for their robustness: the evolution of the demand for their services needs to also be included in a holistic resilience assessment. Using the resilience-compositional demand/supply (Re-CoDeS) framework, the seismic resilience of two civil infrastructure systems, namely, the water distribution system and the cellular communication system of the Kathmandu Valley, Nepal, is assessed in the aftermath of the 2015 Gorkha earthquake. Both systems show a lack of resilience after the earthquake. It is demonstrated that the evolution of the community demand has a large effect on the resilience of civil infrastructure systems. In fact, while the demand of the community for water decreased after the earthquake, a large increase in demand was observed for the cellular communication system, leading to a high lack of resilience. The presented findings may be used to design more resilient systems and to optimize recovery. (c) 2018 American Society of Civil Engineers.

Recently, the need of deploying new wireless networks for smart gas metering has raised the problem of radio planning in the169 MHz band. Unluckily, software tools commonly adopted for radio planning in cellular communication systems cannot be employed to solve this problem because of the substantially lower transmission frequencies characterizing this application. In this manuscript a novel data-centric solution, based on the use of support vector machine techniques for classification and regression, is proposed. Our method requires the availability of a limited set of received signal strength measurements and the knowledge of a three-dimensional map of the propagation environment of interest, and generates both an estimate of the coverage area and a prediction of the field strength within it. Numerical results referring to different Italian villages and cities evidence that our method is able to achieve good accuracy at the price of an acceptable computational cost and of a limited effort for the acquisition of measurements in the considered environments.

Multi-radio access technology (RAT) cellular communication systems limit connected users to utilizing a single RAT even when employing multi-mode user equipment (UE) capable of utilizing multi-RATs. Single-mode access, combined with static spectrum partitioning between co-deployed RATs and independent resource allocation for employed RATs, results in suboptimal spectrum utilization in multi-RAT systems. This paper models user access in multi-RAT systems and proposes enabling multi-mode UE to simultaneously utilize multiple RATs, using multi-RAT carrier aggregation, to improve the performance and spectrum utilization of multi-RAT systems. Several realizations of multi-mode access with varying implementation requirements are presented and discussed. Detailed system-level simulations, for a system co-deploying High Speed Packet Access (HSPA) and Long-Term Evolution (LTE), are performed to investigate the gains and limitations of different user access configurations in multi-RAT systems.

This paper presents results of measurements of penetration losses for common construction material in frequencies between 26.5 GHz and 40 GHz. The results are important to the design and deployment of 5G cellular communication systems that will possibly operate in millimeter wave bands, in addition to the currently used frequencies. The penetration losses were in laboratory using a signal generator, two 20 dBi horn antennas and a spectrum analyzer. The materials tested were thin and thick Styrofoam, thin and thick pressed wood, thin and thick solid wood, window glass, a wooden door and a brick wall and measurements show that brick almost completely blocks the millimeter wave signal, causing attenuations up to 64 dB at 34 GHz, whereas the penetration loss is negligible, as expected. Penetration loss in pressed wood and wood significantly depends on the material's thickness.

This article discusses some of the important structures of the area covered by cellular communications; the following concepts are introduced: achievable, useful coverage and efficiency of use of the reception base station coverage area (BS); the proposed formula for calculating the area of coverage. The aim of the article is to determine the most effective structure of the coverage area of mobile communication.

Cellular communication (CC) is the most popular way to connect people together for real-time communication and data transmission. CC systems have an enormous number of users, and large amounts of data, including user- and system-oriented data, are generated in CC systems every day. To continually provide better service, CC systems are encountering new challenges, such as unbalanced crowd communication behaviors of users and congestion from huge requests of high-quality video transmission. It has become an emerging research topic to study the huge data generated from CC systems and to predict the behaviors of CC systems, so that better quality of services can be provided. In particular, spatial big data analytics, which primarily handles spatial data, is important, because most data generated from CC systems are spatiotemporal-oriented data, and analyses of these data can significantly support the development of CC systems. In this chapter, we comprehensively survey methodologies of spatial big data analytics, study possible applications to support CC systems with spatial big data analytics, and highlight challenging issues.

Blocking is one of the most important challenges in exploiting millimeter-wave for fifth-generation (5G) cellular communication systems. Compared to blockages caused by buildings or terrains, human body blockage exhibits a higher complexity due to the mobility and dynamic statistics of humans. To support development of outdoor millimeter-wave cellular systems, in this paper we present a novel 3D physical model of human body blockage. Based on the proposed model, the impact of human body blockage on frame-based data transmission is discussed, with respect to the system specifications and environment conditions., Comment: Accepted by Physical Communication, in press

Cellular communication systems have undergone a revolutionary change in the past decade. Emerging new technologies have completely transformed the cellular world and are constantly improving the data throughput of today's cellular systems. However, one important factor that is often overlooked is the wireless or OTA signaling used in a cellular system. In fact, OTA signaling is not only the supporting structure of a cellular communication system, which directly affects the stability, reliability, and efficiency of the system, but also an essential factor in the materialization of these new technologies. This article addresses the important roles and key design aspects of OTA signaling in today's cellular communication systems. In particular, we describe the physical design of OTA signaling in various application scenarios to meet specific requirements, such as robustness, latency, coverage, overhead, and detection complexity. We demonstrate how these design aspects are applied in the design of OTA signaling in an LTE system. Finally, we use a special design example to further illustrate the fundamentals of the OTA signaling design presented in this article.

In this paper, the issue of multi-user radio resource scheduling on the downlink of a Long Term Evolution (LTE) cellular communication system is addressed. An optimization model has been proposed earlier, where radio resources for multiple users are jointly allocated at the air-interface. It has been shown that an optimal solution to such a problem may provide reasonable gain over a simply greedy approach. However, the complexity of such an optimal approach could be prohibitively high. By exploiting meta-heuristic methods such as Genetic Algorithm (GA) and Simulated Annealing (SA), the results in this paper show that significant reduction in complexity can be obtained while achieving near-optimal solutions.

In this study, the interaction of Beam Forming and frequency allocation schemes on an OFDM-based system such as LTE or WiMAX is investigated in order to support the maximum capacity and minimum outage probability. The results of simulation show that rank1 precode scheme based on MISO channel, according to what considered in LTE standard, along with the cell region division in order to allocate OFDM frequency carriers lead to a Considerable interest in the total capacity of the network in different traffics.

In cellular communication systems where non-line-of-sight (NLOS) channels are dominant as compared to line-of-sight (LOS) channels, a time difference of arrival (TDOA) localization method can outperform a time of arrival (TOA) localization method, although the TDOA method loses one degree of freedom in the number of usable range estimates when selecting a range estimate as the reference and doubles the variance of range sampling error when subtracting the reference range estimate. In this paper, we first show the computer simulation result on the localization performance of conventional TOA and TDOA methods in mixed LOS/NLOS environments, and then validate it by theoretical analysis. Here, we analyze the root mean square localization error by decomposing it into two factors; for one factor, which is the contribution from range sampling error, we evaluate it by the Cramer-Rao lower-bound, whereas for the other factor, which is the contribution from positively biased NLOS range error, we analyze it by perturbation method. We show that the theoretical result can well explain the localization performance by computer simulation for both the TOA and TDOA methods, and furthermore, we derive a simple condition among the number of cells, the average and variance of NLOS range error distribution which can correctly predict whether the TDOA method outperforms the TOA method or not for the case of all NLOS channels.

The MIMO systems having large number of base station antennas often called massive MIMO or FD-MIMO have received much attention in academia and industry to provide High spectral efficiency, High energy efficiency, High hardware efficiency and processing complexity for future cellular systems such as 4G LTE systems, LTE-Advance, LTE-Advance Pro and Fifth generation cellular communication systems. This paper presents an overview of MIMO technology being applied in LTE and LTE-Advance.

In this paper, we investigate the problem of low probability of intercept (LPI)-based adaptive radar waveform optimization in signal-dependent clutter for joint radar and cellular communication systems, where the radar system optimizes the transmitted waveform such that the interference caused to the cellular communication systems is strictly controlled. Assuming that the precise knowledge of the target spectra, the power spectral densities (PSDs) of signal-dependent clutters, the propagation losses of corresponding channels and the communication signals is known by the radar, three different LPI based criteria for radar waveform optimization are proposed to minimize the total transmitted power of the radar system by optimizing the multicarrier radar waveform with a predefined signal-to-interference-plus-noise ratio (SINR) constraint and a minimum required capacity for the cellular communication systems. These criteria differ in the way the communication signals scattered off the target are considered in the radar waveform design: (1) as useful energy, (2) as interference or (3) ignored altogether. The resulting problems are solved analytically and their solutions represent the optimum power allocation for each subcarrier in the multicarrier radar waveform. We show with numerical results that the LPI performance of the radar system can be significantly improved by exploiting the scattered echoes off the target due to cellular communication signals received at the radar receiver.

By the effect of stratospheric winds, the position and attitude of high altitude platform are in the quasi-stationary state. This paper describes and discusses the swing state of the platform and on this basis, establishes antenna beam coverage geometry model, analyzes the impact of swinging state on handover. the average and maximum handover probability of the different tier cellular have been deduced. The simulation results show that the handover performance of the cells is severely affected by the swing state, especially for outer tier cells, and the effect can be reduced by increase of cell coverage radius to a certain extent.