Faculty Profile

Farzad H. Panahi
Update: 2024-09-19

Farzad H. Panahi

Faculty of Engineering / Department of Electrical, Electronic and Telecommu

Theses Faculty

M.Sc. Theses

  1. Analysis of Wireless-Powered Communication Networks with Random Mobility
    2024
    In this thesis, a wireless-powered communication network model is considered, in which a multi-antenna access point with limited energy, powered by a dedicated wireless power source, communicates with a mobile user. The dynamics of the mobile user, equipped with a single antenna, are modeled using a well-known random mobility model. To leverage the benefits of using a multi-antenna connection, two well-known schemes for multi-antenna transmission are employed: maximum rate transmission and transmit antenna selection. Unlike previous works that only considered static scenarios, the aim of this thesis is to investigate wireless power and information transmission in a scenario with a randomly moving user under the Nakagami fading scheme. Notably, a specific case of the analysis, i.e., the Rayleigh scheme, has not been empirically well-tested, which further enhances the value of the analysis. By considering the two schemes of maximum rate transmission and transmit antenna selection, closed-form expressions are derived for outage probability, average throughput with delay constraint, average throughput without delay constraint, average bit error rate (BER), and throughput with BER constraint. Thus, the impact of dynamic propagation environments with path loss factors and multi-path parameters on the wireless power source-to-access point and access point-to-mobile user links in the wireless-powered communication network can be evaluated. Finally, by introducing an innovation based on fluid antenna systems, as well as through analytical results and computer simulations, the accuracy of the analyses is validated, and the effects of various parameters on system performance are examined.
  2. Performance Analysis of UAV-based FSO Communications
    2024
    Recently, research on the potential use of Free Space Optical (FSO) links as a robust communication link between Unmanned Aerial Vehicles (UAVs) has garnered significant attention in academia and industry. Due to the increasing demand for UAV-based FSO links compared to traditional ground-based FSO links, the optimal design of FSO system parameters based on UAVs (such as optimal values for beam divergence angle, optical detector size, receiver lens aperture, transmission power, and many others) is more challenging and crucial than its ground-based counterpart. Furthermore, to avoid the timeconsuming Monte Carlo simulations, the presence of a simple and analytically tractable channel model is crucial and necessary. In this article, to address this need, a new channel model is developed for the desired system under the influence of atmospheric turbulence conditions. Specifically, for weak turbulence conditions, a new channel model based on the Log-Normal atmospheric turbulence channel is proposed. Subsequently, for moderate to strong turbulence conditions, a statistical channel model with a closed-form expression for the Gamma-Gamma turbulence channel is extracted. These proposed channel models, despite their simplicity and analyzability, incorporate the combined effects of atmospheric turbulence and pointing errors. They also account for limitations in the receiver's field of view and inherent position and orientation deviations of UAVs. Furthermore, to analyze performance metrics more effectively, closed-form expressions for outage probability and Bit Error Rate (BER) are derived. Finally, the validity of the proposed new channel models and the derived outage probability and BER expressions are confirmed using Monte Carlo simulations. The developed results can serve as benchmarks for finding optimal adjustable parameters for UAV-based FSO links under various channel conditions and different levels of UAV instability, without the need for time-consuming Monte Carlo simulations.
  3. Analysis and Simulation of the Impact of Mobility on the Performance of Wireless Communication Networks
    2024
    With the emergence of 5G and future network generations aiming to accommodate a diverse range of use-case scenarios, the boundaries of traditional mobile systems are being pushed. This research delves into how well heterogeneous wireless networks perform when the signal experiences fading that follows the η-μ distribution model. It specifically focuses on the impact of user movement on network performance. By integrating the random waypoint (RWP) model with the η-μ distribution. We effectively model the dynamic behavior of non-homogeneous fading, also we express the probability density function (PDF) and cumulative distribution function (CDF) of received signal power in three-dimensional topologies. Additionally, we analyze the outage probability (OP) and average bit error rate (ABER) to assess mobile system performance, considering co-channel interference (CCI) effects from desired and interfering signals in mobile networks. The expression model characterizes mobile user performance, aiding in evaluating noise and interference impacts. We extend our analysis to various fading channels, including one-sided Gaussian, Nakagami-m, Rayleigh, and Nakagami-q (Hoyt) distributions. examining mobility's impact on these channels. Also examines the ergodic channel capacity (ECC) when users are moving according to a RWP mobility pattern. We express mathematical formulas to calculate this average capacity for various fading environment like η-μ, α-μ and α-η-μ fading channel. Montecarlo simulation validate the expression of η-μ fading model, providing insights into the effect of physical channel and mobility parameters. Lastly, we derive the Effective Energy Efficiency for the η-μ fading model, comparing static and mobile scenarios. This comprehensive analysis facilitates the design of robust 5G and beyond systems, ensuring better performance in diverse fading environments.
  4. Analysis of Co-Existing RF/VLC Cellular Networks
    2024
    This research presents the integration of Visible Light Communication (VLC) and conventional Radio Frequency (RF) wireless networks to enhance the data rate for mobile users, compute coverage, and analyze the average user's rate in joint VLC and RF networks in an indoor environment. Specifically, this thesis aims to examine the challenges posed by hybrid RF/VLC-based cellular networks and consider certain fundamental structures or factors. On the other hand, considering the limitations of RF, Visible Light Communication emerges as a promising technology for interference-sensitive applications such as medical networks. In this thesis, we explore hybrid RF-VLC relay systems that are suitable for applications supporting user mobility. In this system, the end user, assumed to be inside a moving vehicle, is covered by an indoor VLC system, where indoor coverage refers to network coverage inside the vehicle. In contrast, data transmission in outdoor areas is carried out via multiple RF backhaul links. Additionally, it is assumed that the RF link is established by a relay. The performance of this system is analyzed in terms of outage probability and bit error rate (BER). Moreover, for cases where the average SNR on RF links or the optical power of the LED is high, the necessary analysis is conducted. The numerical results presented show that the use of multiple RF backhaul links can significantly improve the overall performance of the RF-VLC system.
  5. Simulation and Analysis of Optimal Cellular Networks based on D2D Communications
    2023
    Before the fifth generation of mobile communication systems, the transmission and reception links between users in a cellular network were established and routed through the base station. This gradually led to increased traffic on the base station and higher latency in sending and receiving information. However, in the fifth generation, with the use of device-to-device (D2D) communications, users in the cellular network could exchange information directly without the mediation of the base station. Using D2D communication in cellular networks reduces traffic on the base station and decreases signal reception delays. If the D2D communication is of the full-duplex underlay type, although it faces the challenge of self-interference, it enhances spectral efficiency. Due to the nature of full-duplex communication, which involves limited distances between two devices, it reduces the required transmission power and saves energy. Moreover, due to the reduced transmission power, the level of self-interference is significantly lowered. This thesis examines the advantages of using full-duplex underlay D2D communication in cellular networks. For this purpose, a cellular network is considered that includes a base station, cellular users, and D2D users. The locations of these users in the cell follow Poisson point processes. To evaluate network performance, approximations based on stochastic geometry are applied in calculating the coverage probability and the sum of the bit rates for cellular and D2D users. Under certain conditions, where the number of D2D links is sufficiently large, the obtained approximations simplify to a closed-form expression, allowing us to analyze the behavior of the sum of bit rates in relation to various network parameters. It is demonstrated that underlay D2D communication significantly increases the spectral efficiency of the network. Furthermore, it is observed that even a slight reduction in self-interference in full-duplex D2D communications leads to a substantial increase in spectral efficiency compared to half-duplex communications. Finally, the results obtained for coverage probability and sum bit rate are compared with multi-cell networks under standard frequency reuse and fractional frequency reuse scenarios. It is shown that employing multi-cell networks with frequency reuse scenarios increases the coverage probability for users but, conversely, reduces the total bit rate transmitted by users.
  6. Performance Analysis of Cellular-Relay Vehicle-to-Vehicle Communications
    2023
    Wireless communication for vehicles is an emerging trend in the automotive and drone industries, offering solutions to pressing issues such as traffic congestion and road or air accidents. Within the framework of the Third Generation Partnership Project (GPP3), vehicle communication is classified as vehicle-to-everything (V2X) communication, encompassing vehicle-to-infrastructure (V2I), vehicle-toperson (V2P), and vehicle-to-vehicle (V2V) communication. V2V communication, in particular, presents diverse applications, including collision avoidance, in-car Internet access, and autonomous driving. The primary objective of vehicle wireless communication is to enhance safety, necessitating low latency and high reliability in such communications.To facilitate direct communication, specialized narrowband short-range communication (DSRC) protocols are employed. Nevertheless, these protocols exhibit functional limitations and fall short of delivering optimal outcomes. Furthermore, DSRC faces restrictions in terms of spectrum availability and data transmission, relying on a 5.9 GHz bandwidth for multiple access control (MAC). However, in CSMA mode and on heavily trafficked roads, its effectiveness diminishes. Additionally, the deployment and operation of DSRC infrastructure, such as Roadside Units (RSUs), incur significant expenses.To address these challenges, the utilization of cellular relay in vehicle communication, along with the application of cellular networks such as LTE and 5G, has been proposed. The 3GPP group has defined several crucial scenarios for V2X and V2V communications, encompassing both direct mode and cellular relay mode. In the direct communication mode, vehicles communicate directly with each other. Conversely, in the cellular relay mode, messages are initially transmitted to the cellular terminal (cellular relay) through a remote connection and suBsequently relayed to the destination device via another remote connection. In the following discussion, drones are employed as cellular relays, and the impacts of drone height, car density, and vehicle-to-vehicle communication are explored. Moreover, the influence of increasing the minimum requested rate on the power and bandwidth allocated by the unmanned aerial vehicle (UAV) to the vehicle is examined.
  7. Data Offloading of Base Stations in Cellular Communication Networks
    2023
    Cellular networks are struggling in recent years to support high data rates and system capability, as well as the growth of smartphone devices and mobile apps that use data. Future growth has made managing traffic for cell operators one of their biggest difficulties. Mobile data discharge is a low-cost way to lighten the burden on cell phone networks. In this thesis, a method to speed up cell traffic with the device using device communication is presented. The system model structure in question is known as the WPDO Network, and it has been described in this thesis along with how it integrates with power transmission technology. To determine the potential for cellular and D2D users, the structure employs the average power transfer of D2D transmitters and the lowest expected power of base stations. These connections choose the most effective time allocation agent to decide the WPDO network's optimum energy efficiency. We will assess the energy efficiency of the WPDO network by looking at resources with non-geometric forms in two-dimensional space, and by creating an algorithm to maximise WPDO network energy efficiency, we will gain knowledge about network architecture at the system level. Data traffic in cellular networks is greatly decreased as the discharge radius grows due to increased network efficiency, which also impacts the radius of the data evacuation regions. Finally, numerical findings are evaluated and simulated using MATLAB software.
  8. Performance Analysis of Intelligent Reflecting Surfaces Assisted UAV Communication Networks
    2023
    The growing need for wireless connection, as well as the advent of the concept of the Internet of Things, necessitate the development of new communication paradigms that will, in turn, enable a multitude of new applications and disruptive technologies. The current contribution investigates the use of the recently introduced intelligent reflecting surface (IRS) concept in unmanned aerial vehicle (UAV) enabled communications with the goal of extending network coverage and improving communication reliability as well as spectral efficiency of Internet of Things (IoT) networks. We begin by obtaining tractable analytic formulas for the feasible symbol error rate (SER), ergodic capacity, and outage probability of the given setup. We then construct stringent upper and lower constraints for the average signal-to-noise ratio (SNR). Our derivations are then compared to the related asymptotic performance, which demonstrates that the asymptotic SNR lies inside the region between the derived bounds, and approaches either bound depending on the number of reflecting elements (REs). The provided findings show that using the IRS is very effective, as they help to improve the attainable SER by five orders of magnitude. We also show that IRSassisted UAV communication systems can have ten times the capacity of traditional UAV communications in terms of attainable ergodic capacity.
  9. Cognitive and Energy Harvesting-Based D2D Communication in Cellular Networks
    2022
    Demand for traffic volumes and high speeds in communication networks continues to grow exponentially. On the other hand, the most valuable factor in these networks is the frequency spectrum, which is limited and with this huge volume of demand is being saturated. One of the solutions proposed in this field is the use of device-to-device (D2D) communication. But another issue in this regard is the supply of energy needed to transmit information in communication (D2D). The solution proposed in this regard is energy harvesting (EH). In the basic paper selected, D2D transmitters derive their energy from environmental interference and will use one of the channels dedicated to cellular network users. In this paper, the two basic approaches of different spectrum access RSA (random spectrum access) and PSA (prioritized spectrum access)) for cellular communications are investigated. In the RSA approach, all available channels, including those used in D2D transmitters, will be randomly used for cellular communications. But in the PSA approach, the channel dedicated to D2D transmitters will be used for cellular communication when all other channels are occupied. In this article, The channel has been used as an influential factor to describe the relationship of energy harvesting And according to that, the probability of outage in the receivers has been investigated. But other energy models can be used to examine the use of energy harvesting in D2D communications. The model used for energy in this paper is a simplified model of energy that is independent of the channel and depends on the wavelength, transmitter power and distance between receiver and transmitter. By considering this energy model, we can rewrite the relationships related to outage and other relationships related to the selected base paper and examine the effect of factors on these relationships and also compare these effects with the base article. But the model used to describe the location of users and base stations is PPP or Poisson point process. The location of mobile systems may exhibit some clustering and repulsion behaviors. Therefore, the DPP model is used to describe the location of users and base stations that incorporate these characteristics. Another article has been selected to investigate this issue, but this article does not use cognitive radio to send information. Using the RSA and PSA models available in the first base paper and used in the PPP model, they can be entered into the DPP model, which are a kind of radio cognitive, and the results can be examined through relationships and simulation results.
  10. Performance Analysis of UAV-based Communication Networks with Device-to-Device Communications
    2022
    هنگامی که زیرساخت های ارتباطی به دلیل بلایای طبیعی آسیب می بیند، استفاده از هواپیمای بدون سرنشین (UAV) به عنوان ایستگاه پایه هوایی (BS) و ارتباطات دستگاه به دستگاه از جمله استراتژی های ضروری برای خدمات یکپارچه و قابل اعتماد است. در این پایان نامه، استقرار یک وسیله نقلیه هوایی بدون سرنشین (پهپاد) به عنوان یک ایستگاه پایه هوایی برای ارائه ارتباطات بی سیم به یک منطقه معین مورد تجزیه وتحلیل قرار می گیرد. به طور خاص، همزیستی بین پهپاد، در حالت فروسو و فراسو و یک شبکه ارتباطی دستگاه به دستگاه (D2D)در نظر گرفته شده است. برای این مدل، یک چارچوب تحلیلی برای تحلیل پوشش و نرخ و انرژی مؤثر به دست آمده است. در این سناریو که مکان پهباد ثابت است، میانگین احتمال پوشش و مجموع نرخ سیستم برای کاربران در منطقه به عنوان تابعی از ارتفاع پهپاد و تعداد کاربران D2D ، احتمال انتقال موفقیت آمیز (در حالت فراسو) و میانگین مجموع نرخ و EE شبکه بر اساس اصول هندسه تصادفی به دست آمده است. نتایج شبیه سازی و تحلیلی نشان می دهد که بسته به تراکم کاربران D2D ، مقادیر بهینه برای ارتفاع پهپاد وجود دارد که منجر به حداکثر مجموع نرخ سیستم و احتمال پوشش می شود. بااین حال، قابلیت اطمینان ارتباطی BS هوایی و بازده انرژی ارتباطات D2D ممکن است به دلیل همزیستی طیف مشترک جفت های D2D و پهبادکاهش یابد. ما همچنین به اثرات تراکم کاربران متصل به UAV و کاربران D2D ، بر روی EE و مجموع نرخ به عنوان معیارهای عملکرد در سناریوی فراسو می پردازیم. در انتها یک راه حل پیشنهادی برای سناریو ایمنی عمومی که در آن برای ارسال یک داده ثابت به تمام کاربران، اعم از کاربران سلولی و کاربران D2D ،پیشنهاد داده ایم که در آن کاربران سلولی قابلیت ارسال داده به D2Dها رادارند.
  11. Energy Management Optimization in Renewable Energy Based Cellular Networks
    2022
    One of the most important issues in the analysis and design of wireless telecommunication systems is the discussion of energy consumption. In the past, all cellular networks provided their required energy from the electricity grid. Renewable clean as an effective alternative to reduce the use of energy produced by fossil fuels and store excess energy in base stations and ultimately sell excess energy to the grid and reduce energy costs of the two approaches used The first approach of the base station sleep strategy in the telephone network In order to maximize the energy storage in the network, according to the network traffic load and the second approach, the integration of renewable energy with the electricity network has been done simultaneously for a one-day operational cycle. The aim of the mobile operator is to reduce its total energy cost by optimizing the amount of energy obtained from local renewable energy sources in each time period. The power grid, which is increased by the first approach, is also a constrained optimization used to deal with the uncertainty of renewable energy production.
  12. Simulation and Design of an Efficient Model for Energy Charging over Rechargeable Wireless Sensor Networks
    2021
    The next generation’s sensor nodes will be more intelligent, energy conservative and perpetual lifetime in the set-up of wireless sensor networks (WSNs). These sensors nodes are facing the overwhelming challenge of energy consumption which gradually decreases the lifetime of overall network. Wireless power transfer (WPT) is one of the most emerging technologies of energy harvesting that deploys at the heart of sensor nodes for efficient lifetime solution. A wireless portable charging device (WPCD) is drifting inside the WSN to recharge all the nodes which are questing for the eternal life. In this paper, we aspire to optimize a multi-objective function for charging trail of WPCD, and self-learning algorithm for data routing jointly. We formulated that the objective functions can optimize the fair energy consumption as well as maximize the routing efficiency of WPCD. The fundamental challenge of the problem is, to integrate the novel path for WPCD by applying the Nodal A* algorithm. We proposed a novel method of sensor node’s training for intellectual data transmission by using of clustering and reinforcement learning (SARSA) defined as clustering SARSA (C-SARSA) along with an optimal solution of objective functions. The whole mechanism outperforms in terms of trade off between energy consumption and stability (fair energy consumption among all nodes) of the WSN, moreover, it prolongs the lifetime of the WSN. The simulated results demonstrate that our proposed method did better than compared literature in terms of energy consumption, stability, and lifetime of the WSN.
  13. Coverage Expansion of UAV-Based Communication Networks
    2021
    One of the most important issues in the analysis and design of wireless communication systems is investigate of its coverage and efficiency. Coverage efficiency means providing maximum communication coverage and establishing quality communication with users, which maximizing it is one of the main goals in designing new and advanced fifth generation communication systems. In this thesis, we intend to provide communication coverage in the urban environment by using UAVs as aerial BS. First, the factors affecting the efficiency of the coverage by UAVs and the challenges and advantages of these systems are examined. In order to improve the interference situation, we equip drone systems with directional antennas and examine the height of UAVs relative to cells with different congestion using symmetric and asymmetric methods, and finally, control the intercellular interference according to the composition of the directional antenna, symmetric and asymmetric height and frequency reuse. Then we examine the problem of maximum coverage with the minimum number of UAVs and provide a mathematical model to examine all the coverage limitations in the urban environment. Then, we introduce an innovative solution algorithm to improve the coverage situation in the urban environment and examine the system functions for different congestion conditions.
  14. Simulation and Performance Analysis of Cell Free mMIMO Communication Networks
    2021
    Numerous types of research have been done in recent years on Multi-Input, Multi-Output, and Massive Multi Input Multi Output. In all of these researches, intercell interface, delay, and Spectral Efficiency have been evaluated. Although Massive MIMO standards in 5G spectral efficiency, Energy efficiency, delay, etc., have been improved significantly, intercell interference issues and handover impact the performance and users' services at the edge of the cell intensely. Cell-Free Massive Multi Input Multi Output as an emerging technology to prepare the users increasing demands and expected increased data rate beyond 5G networks has attracted considerable attention. The main idea of this project is that several distributed Access Points on a limited number of users in one time-frequency block are responsible for the service. In this case, each user receives the services from APs that have the minimum power to delete the intercell interface. Considering the high signaling volume to estimate the channel, signal processing, cooperation, and contribution of APs, it originates essentially to evaluate different levels of signal processing implementation. In this thesis, accomplishments have been made to evaluate four different levels of signal processing or user-centric processing, which are in the best performance. In addition, drone UAVs have been reviewed, which has better performance than user-centric scenarios.
  15. Energy Management for Wireless Networks with Renewable Energy Powered Base Stations and Device-to-Device Communications
    2021
    In recent years, due to the increase in the number of users and telecommunication towers and the need for high transmission rates, energy consumption in telecommunication systems has increased significantly, which in many cases, including economic and environmental issues. It has brought challenges. Therefore, Green Communication, using the technologies provided in the new generations of wireless communications such as device to device (Dezz Device), as an effective step in managing energy consumption. And its efficiency is known to improve. In device-to-device communication, the information-seeking user communicates with a close user instead of being directly connected to and powered by the base station. In this case, the power consumption of the base station is reduced and the system will be more energy efficient. In this dissertation, first, wireless cellular telecommunication systems are reviewed and then several solutions to reduce energy consumption are presented. The main focus of this research is on energy consumption management in wireless telecommunication systems with two types of cellular and device-to-device communication that part of the power required by the base station is provided by renewable energy sources such as solar and wind.
  16. Design and Simulation an Energy Efficient Optimal Model in Underwater Wireless Sensor Networks
    2021
    در دهه ی گذشته، شبکه ی حسگر بیسیم زیرآب (UWSN)، به عنوان زمینه ی پرکاربرد IoUT، مورد توجه بسیاری از مراکز دانشگاهی و صنعتی قرار گرفته است. در ارتباطات بیسیم زیرآب بیشتر محدوده ی طیف فرکانس رادیویی با فرکانس به شدت تضعیف میشود. سیگنال نوری نیز به شدت به ویژگی کدربودن آب دریا وابسته بوده و از اثرات پدیده ی پراکندگی رنج میبرد. در این میان، سیگنال صوتی برگرفته از مزیت انتقال داده بروی مسافتهای طولانی، فنآوری کارآمد و پرکاربرد در لایه ی فیزیکی UWSN، است. رویکرد رایج در لایه ی شبکه ی UWSN، مسیریابی برای انتقال داده های حسگری از گره های زیرآبی به چاهک بروی سطح آب میباشد. مصرف انرژی بالا، تنگنای در منبع توان گره، پهنای باند کم در دسترس، تاخیر انتشار کمابیش بالا برگرفته از سرعت انتشار پائین سیگنال صوتی (1500 متر بر ثانیه)، در کنار ویژگی بی ثبات در زمان و مکان فضای زیرآب، طراحی الگوریتم مسیریابی در UWSN، را دشوار و پیچیده مینماید. مسیریابی Anypath، به عنوان نسل اولیه ی پروتکلهای مسیریابی در UWSN، یک راهبرد کارآمد برای بهره وری انرژی و کنترل میانگین تاخیر انتها به انتها میباشد. در این پایاننامه، با بهره گیری از مزیتهای روشهای یادگیری تقویتی در تعامل با محیط پویا و ناهمگن، یک پروتکل مسیریابی مستقل از موقعیت مکانی گره ی زیرآبی مبتنی بر الگوریتم Q-learning، طراحی و پیشنهاد میشود. به طور خاص، با تعریف دو تابع پاداش وابسته به انرژی و اطلاعات عمق، یک هم وزنی در مصرف انرژی گره های زیرآبی ایجاد میشود. نتایج شبیه سازی در نرم افزار متلب نشان میدهد که پروتکل پیشنهادی با ماهیت تحرک گره های حسگر زیرآبی سازگار میباشد. همچنین، در هم سنجی با دو نمونه ی برجسته از پروتکل مسیریابی در زیرآب، زمان عمر شبکه و تاخیر انتها به انتها در UWSN، را توسعه میدهد.
  17. Power-Consumption Management in Multi-Layer EH-Enabled Cellular Networks
    2021
    یکی از مسائل مهم در تحلیل و طراحی سیستم های مخابراتی بیسیم، بهره وری انرژی می باشد. منظور از بهره وری انرژی (Energy Efficiency)، تعداد بیت های انتقال داده شده بین فرستنده و گیرنده در هر واحد ژول انرژی میباشد. در سال های اخیر مصرف انرژی در شبکه های بی سیم و به ویژه در شبکه های تلفن همراه، به دلیل افزایش قابل ملاحظه تعداد کاربران افزایش چشمگیر داشته و تعداد دکل های مخابراتی، به شدت بالا رفته است به گونه ای که بهره وری انرژی به دلیل مسائل زیست محیطی و اقتصادی بعنوان یکی از اهداف عمده طراحی در شبکه های تلفن همراه بی سیم توجه تمام اپراتورهای شبکه و مراکز تحقیقاتی دانشگاهی وصنعتی را به خود جلب کرده است. افزایش تعداد ایستگاه های پایه موجب افزایش مصرف انرژی و افزایش انتشار دی اکسیدکربن گردیده است. در این مقاله ما به بررسی برخی روش های کاهش مصرف انرژی در برنامه مخابرات سبز پرداخته و بر روی روش های زوم سلولی و خواب سلولی که در کاهش مصرف انرژی در شبکه های سلولی مورد استفاده قرار می گیرد تمرکز می نمائیم به گونه ایی که استفاده از روش های مذکور موجب افزایش بهره وری انرژی شود و همچنین الزامات ارائه سرویس به کاربران نیز مد نظر قرار گیرد.
  18. Analysis and simulation of EH-enabled wireless sensor networks
    2020
    Nowadays , wireless sensor networks are used in many applications for monitoring activities in different environments due to its low cost and easy communication. In these networks, sensors have access to finite energy resources, so in order to increase the lifetime of thr networks, recently, researchers are looking for ways to reduce energy consumption and therfore to increase the network lifetime. Indeed, there are some solutions to save availabe energy and maintain the performance of a wireless sensor network (WSN) in different network layers. Thus, energy harvesting (EH) is an excellent technique for increasing lifetime of WSNs and improving the shape of communicatn links via simultaneously wireless information and power transmission (SWIPT) schemes while keeping the quality of service (QoS). In this thesis, in addition to a general review for the existing methods, an EH-enabled scheme is proposed for the orthogonal frequency division multiplexing (OFDM) system, in which the power and subcarrier allocation problem is formulated to maximize the energy harvesting where quality of service (QoS) remains intact. The proposed scenarios are then extented for multi-hop communication networks .
  19. Design and Simulation of Energy–Efficient Networks based on Machine-to-Machine Communications
    2020
    High energy efficiency is an essential item for enabling massive machine-type communications (MTC) over the existing cellular networks. This Research focuses on energy consumption modeling, battery lifetime analysis, lifetime-aware scheduling, and transmit power control for massive MTC over cellular networks. Indeed, we consider a realistic model for MTC energy consumption and network battery-lifetime. Analytic expressions are derived to evaluate the impact of scheduling on both the individual and network battery lifetimes. The derived expressions are then used for uplink scheduling and transmit power control for mixed-priority MTC traffic in order to maximize the network lifetime. Besides the main strategy, low complexity analyses with limited feedback requirement are investigated, and the results are extended to existing LTE networks. In addition, the energy efficiency, spectral efficiency, and network lifetime tradeoffs in resource provisioning and scheduling for MTC over Energy-Harvesting (EH) based networks are investigated. The simulation results confirm that the proposed EH-based strategy can provide substantial network lifetime improvement and network maintenance cost reduction in comparison with the existing scheduling schemes.