Integrated Satellite-Terrestrial System Capacity Over Mix Shadowed Rician and Nakagami Channels

In this paper, we evaluate the ergodic capacity analysis of a integrated satellite-terrestrial cooperative communication system under independent and non-identical shadowed Rician and Nakagami-m fading channels. Multiple cooperative relay nodes are assumed between satellite and the destination node. Amplify-and-forward (AF) cooperative protocol is used at each fixed relay node for signal amplification. While for signals combining at the destination node, the maximum ratio combining(MRC) technique is exploited. An analytical approach is derived to evaluate the performance of the system in terms of ergodic capacity. We derive the approximate closed-form expression for calculating the ergodic capacity of the proposed system. It is shown that the derived analytical expression is very tight and applicable to the general operating conditions with the help of satellite channel date available from the literature. The analytical results are compared with Monte Carlo simulations, and they seem to agree well

Spectral Efficiency Evaluation for Selection Combining Diversity Schemes under Worst Case of Fading Scenario

The results of spectral efficiencies for optimum rate adaptation with constant power (ORA) and channel inversion with fixed rate (CIFR) schemes over uncorrelated diversity branch with Selection Combining (SC) available so far in literature are applicable only for m?1.This paper derived closed-form expressions for the spectral efficiency of dual-branch SC over uncorrelated Nakagami-0.5(m<1) fading channels. This spectral efficiency is evaluated under ORA and CIFR schemes. Since, the spectral efficiency expression under ORA scheme contains an infinite series, hence bounds on the errors resulting from truncating the infinite series have been derived The corresponding expressions for Nakagami-0.5 fading are called expressions under worst fading condition with severe fading. Finally, numerical results are presented, which are then compared to the spectral efficiency results which have been previously published for ORA and CIFR schemes. It has been observed that by employing SC, spectral efficiency improves under ORA, but does not improve under CIF

Average Channel Capacity Evaluation for Selection Combining Diversity Schemes over Nakagami-0.5 fading Channels.

This paper provides Closed-form expressions for the average channel capacity and probability of outage of dual-branch Selection Combining (SC) over uncorrelated Nakagami-0.5 fading channels. This channel capacity and probability of outage are evaluated under Optimum Power with Rate Adaptation (OPRA) and Truncated channel Inversion with Fixed Rate transmission (TIFR) schemes. Since, the channel capacity and probability of outage expressions contain an infinite series, the series are truncated and bounds on the truncated errors are presented. The corresponding expressions for Nakagami-0.5 fading are called expressions under worst fading condition with severe fading. Finally, numerical results are presented, which are then compared to the channel capacity and probability of outage results for no diversity case, which has been previously published under OPRA and TIFR schemes. It has been observed that OPRA provides improved average channel capacity and probability of outage, as compared to TIFR under worst case of fading

New Approaches Using Cognitive Radio in Green Networking

The green networks are energy-efficient network architectures and we consider them as the basis of the wireless communication optimizing energy usage. Indeed, future communication technologies are moving in this direction, meaning that they will be less energy-intensive and, in some cases, even energy self-sufficient. Specifically, cognitive radio (CR) networks, cooperative relay networks, and non-orthogonal multiple access (NOMA) techniques have been considered as effective means to facilitate energy harvesting (EH) and a power spectrum allocation for the minimization of total transmit power, hence, making the wireless communication greener. The dissertation consists of three research sections corresponding to the aims. The first aim deals with an radio frequency (RF) wireless energy transfer model for D2D systems. In order to harvest more energy, a multiple-antenna base station and a power beacon are adopted for the D2D transmission network. We derive expressions outage probability in closed-forms. Further, independent simulations are used to validate the exactness of the theoretical expressions. In the second aim, new cooperative system models are proposed and studied. To reach the second aim, the secondary source acts as a relay and employs Amplify and Forward (AF) mode to serve distant NOMA users under a given interference constraint. To provide a detailed examination of the system performance metrics, we derived closed-form formulas for the outage probability and average throughput of the multi-users in the presence of interference constraints. In the last aim of the dissertation, we designed a new system model for a hybrid satellite-terrestrial cognitive network (HSTCN) relying on NOMA interconnecting a satellite and multiple terrestrial nodes. Reliability and security of transmission were studied to minimize the total transmit power. To reach the third aim, we examined the following performance factors: outage probability, hardware impairment, intercept probability, and average throughput. The novel closed-forms expressions of these performance factors are derived. The last but not at least, we simulated the new HSTCN system model. The achieved results figured that the new proposed approaches make it possible to take into account service quality requirements and are applicable in future green networking.Zelené sítě jsou energeticky efektivní síťové architektury a považujeme je za základ bezdrátové komunikace optimalizující spotřebu energie. Tímto směrem se ubírají budoucí komunikační technologie, což znamená, že budou méně energeticky náročné a v některých případech dokonce energeticky soběstačné. Kognitivní rádiové (CR) sítě, kooperativní relay sítě a neortogonální vícenásobné přístupové (NOMA) techniky jsou považovány za účinný prostředek k usnadnění získávání energie (EH) a přidělování výkonového spektra pro minimalizaci celkového vysílacího výkonu, díky čemuž je bezdrátová komunikace zelenější. Disertační práce se skládá ze tří výzkumných částí odpovídajících cílům. První cíl se zabývá modelem bezdrátového přenosu radiofrekvenční (RF) energie pro systémy D2D. Aby bylo možné získat více energie, jsou pro přenosovou D2D síť použity základnové stanice s více anténami a napájecím radiomajákem. Pro navržený model jsou odvozeny pravděpodobnosti výpadků, kdy tyto výrazy jsou v uzavřené formě. Dále jsou k ověření platnosti získaných teoretických výrazů použity nezávislé simulace. Ve druhém cíli jsou navrženy a zkoumány nové modely kooperativního systému. Aby bylo dosaženo druhého cíle, sekundární zdroj funguje jako relay uzel a využívá režim AF (Amplify and Forward), který slouží vzdáleným NOMA uživatelům za specifických interferenčních podmínek. Abychom poskytli podrobné zhodnocení výkonnostních metrik systému, odvodili jsme vztahy v uzavřené formě pro pravděpodobnost výpadků a průměrnou propustnost více uživatelů za přítomnosti interferenčních omezení. V posledním cíli disertační práce jsme navrhli nový systémový model pro hybridní satelitně-terestrickou kognitivní síť (HSTCN) založenou na neortogonálním vícenásobném přístupu (NOMA) propojující satelit a více terestrických uzlů. Zkoumána byla spolehlivost a zabezpečení přenosu s důrazem na minimalizaci celkového vysílacího výkonu. Pro dosažení třetího cíle jsme zkoumali následující výkonnostní faktory: pravděpodobnost výpadku, poškození hardwaru, pravděpodobnost zachycení a průměrnou propustnost. Pro tyto výkonnostní faktory jsou odvozeny v uzavřených formách nové výrazy. V neposlední řadě jsme rovněž simulovali nový systémový HSTCN model. Dosažené výsledky potvrdily, že nově navržené přístupy umožňují zohledňovat požadavky na kvalitu služeb a jsou použitelné v budoucích zelených sítích.440 - Katedra telekomunikační technikyvyhově

Modeling Poisson Error Process on Wireless Channels

Burst error modeling has seen extensive research and progress over several decades evolving into ever more complex modeling techniques used today. This paper analyzed usefulness of the most prominent generative and descriptive (analytical) methods. Data containing error bits and packets from real wireless transmission has been used to obtain statistical information about error burst and gap behavior in the channel and various generative and descriptive modeling techniques were applied to model the error process with the goal of establishing advantages and disadvantages of each technique. Generative methods were represented by the commonly implemented Elliot’s model with parameters calculated using a generalized algebraic form and  descriptive methods were represented by one of the most flexible exponentially shaped distributions with regard to parameterization and heavy-tailed function modeling - gamma distribution, and lastly a technique represented by Markov modulated Poisson process (MMPP-2) producing second-order hyper-exponentially distributed characteristics. Results of the experiments were highly in favor of Elliot’s and MMPP-2 model demonstrating possible application of MMPP-2 model in application to commonly observed exponentially-shaped error process on the wireless channel

Proceedings of the Fifth International Mobile Satellite Conference 1997

Satellite-based mobile communications systems provide voice and data communications to users over a vast geographic area. The users may communicate via mobile or hand-held terminals, which may also provide access to terrestrial communications services. While previous International Mobile Satellite Conferences have concentrated on technical advances and the increasing worldwide commercial activities, this conference focuses on the next generation of mobile satellite services. The approximately 80 papers included here cover sessions in the following areas: networking and protocols; code division multiple access technologies; demand, economics and technology issues; current and planned systems; propagation; terminal technology; modulation and coding advances; spacecraft technology; advanced systems; and applications and experiments

Satellite Communications

This study is motivated by the need to give the reader a broad view of the developments, key concepts, and technologies related to information society evolution, with a focus on the wireless communications and geoinformation technologies and their role in the environment. Giving perspective, it aims at assisting people active in the industry, the public sector, and Earth science fields as well, by providing a base for their continued work and thinking

Wireless Channel Characterization in the 5 GHz Microwave Landing System Extension Band for Airport Surface Areas

In this project final report, entitled "Wireless Channel Characterization in the 5 GHz Microwave Landing System Extension Band for Airport Surface Areas," we provide a detailed description and model representation for the wireless channel in the airport surface environment in this band. In this executive summary, we review report contents, describe the achieved objectives and major findings, and highlight significant conclusions and recommendations

Spectrum sensing for cognitive radios: Algorithms, performance, and limitations

Inefficient use of radio spectrum is becoming a serious problem as more and more wireless systems are being developed to operate in crowded spectrum bands. Cognitive radio offers a novel solution to overcome the underutilization problem by allowing secondary usage of the spectrum resources along with high reliable communication. Spectrum sensing is a key enabler for cognitive radios. It identifies idle spectrum and provides awareness regarding the radio environment which are essential for the efficient secondary use of the spectrum and coexistence of different wireless systems. The focus of this thesis is on the local and cooperative spectrum sensing algorithms. Local sensing algorithms are proposed for detecting orthogonal frequency division multiplexing (OFDM) based primary user (PU) transmissions using their autocorrelation property. The proposed autocorrelation detectors are simple and computationally efficient. Later, the algorithms are extended to the case of cooperative sensing where multiple secondary users (SUs) collaborate to detect a PU transmission. For cooperation, each SU sends a local decision statistic such as log-likelihood ratio (LLR) to the fusion center (FC) which makes a final decision. Cooperative sensing algorithms are also proposed using sequential and censoring methods. Sequential detection minimizes the average detection time while censoring scheme improves the energy efficiency. The performances of the proposed algorithms are studied through rigorous theoretical analyses and extensive simulations. The distributions of the decision statistics at the SU and the test statistic at the FC are established conditioned on either hypothesis. Later, the effects of quantization and reporting channel errors are considered. Main aim in studying the effects of quantization and channel errors on the cooperative sensing is to provide a framework for the designers to choose the operating values of the number of quantization bits and the target bit error probability (BEP) for the reporting channel such that the performance loss caused by these non-idealities is negligible. Later a performance limitation in the form of BEP wall is established for the cooperative sensing schemes in the presence of reporting channel errors. The BEP wall phenomenon is important as it provides the feasible values for the reporting channel BEP used for designing communication schemes between the SUs and the FC