Abstract. In this paper, we concentrate on a massive MIMO outdoor optical wireless communication system, in which power modulation is utilized through an atmospheric turbulence. Then, we proposed a maximum likelihood blind detection algorithm based on channel statistics. Following that, we provide the optimal decision thresholds. Furthermore, we analyze the average symbol error rate of the algorithm under a given average transmit powerconstraint to improve system performance.
The essential precept of this method is to scramble every OFDM signal with various scrambling sequences while it‟s smallest for transmission of PAPR value. Obviously, this method does not ensure that to decrease the value of PAPR lower to a certain threshold, but it can decrease the high PAPR appearance probability to a great range. Thus, this approach type implicates, firstly the Selective Mapping SLM and then the Partial Transmit Sequences PTS. Appling scrambling rotation of SLM technique to all sub-carriers autonomously, but scrambling of PTS technique applied to the part of sub- carriers. The two techniques can be considered to apply each scenario without constraint within sub-carriers number and modulation type. Nevertheless, in order to indicate the successful recovery at the receiver, additional information is needed. That leads to the use of low-bandwidth and high-complexity hardware implementation.
This paper studies transmit power minimization and fairness for the system under a probabilistic outage constraint for a multi-user downlink NOMA system, where perfect CSI is known at receivers and only average CSI is available at the base station (BS), i.e., only the location information of the users is known to the BS. We assume that the users are static and consider the SIC decoding order based on the distances between users and the BS. Specially, an optimal power allocation scheme is derived in a closed-form expression under the outage constraint in NOMA systems. In addition, comparisons between the NOMA scheme and the conventional OMA scheme is conducted from the power consumption with the outage constraint. The results conclude that the NOMA scheme outperforms the conventional OMA scheme from the perspective of power consumption and fairness.
Many researchers found that a distributed algorithm is an optimal solution capable of solving the power mismatch problem. The development of distributed consensus algorithms has received a great deal of attention in recent years, due to its broad applications, e.g., in unmanned air vehicles, multivehicle systems, and sensor networks. It has become one of the mainstream solutions for the energy management problem, where many researchers have conducted researches on the economic dispatch problem (EDP) and optimal resource management problem. Distributed consensus algorithm has become an optimal solution to address the energy mismatch issue, where the incremental cost of power generation is indicated as a consensus variable, while the local power mismatch is assigned as a feedback variable to drive consensus variable to a common value in references [15–17]. Authors in reference  investigated convergence performance against feedback gain with an upper boundary being determined. Along this way, an optimal allocation strategy of the storage devices with consideration of the generation ramp rates was also studied in . The application of distributed algorithms with regard to battery energy storage systems (BESS) have been found in many literatures [18–20]. In particular, a cooperative distributed control scheme was employed to coordinate battery agents to reduce power mismatch and maximize the energy efficiency of the batteries, while the robustness and plug-and- play capability of the algorithm have been considered in . In , authors developed an advanced algorithm to overcome the power imbalance caused by wind uncertainty. Another example was to apply the distributed algorithm to a hybrid energy storage system in the DC microgrid with a load sharing strategy, where the frequency stability in a microgrid system was improved . In the meantime, electric vehicles (EVs) as a popular schedulable load can be aggregated and regulated with a distributed peer-to-peer MAS framework in order to support sustainable operation of the microgrid system . In , the authors proposed an EV power controller based on a renewable generation and load demand forecasting curve to strengthen frequency stability in an islanded microgrid.
It is known that power consumption is the main constraint on the sensor network, there is a focus on increasing the lifetimes of sensor nodes through power generation, power conservation, and power management. Now a day, research is in designing small MEMS RF components for transceivers, including capacitors, inductors, etc. Micro-sized inductors are a challenge in this area. MEMS power generating device is developed which vibrates at the frequency of the external vibrating source and create the electoral energy. 
Economic dispatch (ED) is the power demand allocating process for the committed units at minimum generation cost while satisfying system and operational constraints. Increasing cost of fuel price and electricity demand can increase the cost of thermal power generation. Therefore, robust and efficient optimization algorithm is required to determine the optimal solution for ED problem in powersystem operation and planning. In this paper the lightning search algorithm (LSA) is proposed to solve the ED problem. The system constraints such as power balance, generator limits, system transmission losses and valve-points effects (VPE) are considered in this paper. To verify the effectiveness of LSA in terms of convergence characteristic, robustness, simulation time and solution quality, the two case studies consists of 6 and 13 units have been tested. The simulation results show that the LSA can provide optimal cost than many methods reported in literature. Therefore, it has potential to solve many optimization problems in power dispatch and powersystem applications.
The coordinated voltage control has been done with DGs reactive power control and OLTC operation. The result indicates that involving DGs reactive powers in the voltage control will result in a reduction of number of OLTC operations and the reduction of the voltage level in the distribution system. Further, the results also indicate that from the coordinated voltage control, the losses can be decreased. In recent years, distributed generation, as clean natural energy generation and cogeneration system of high thermal efficiency, has increased due to the problems of global warming and exhaustion of fossil fuels. Many of the distributed generations are set up in the vicinity of the customer, with the advantage that this decreases transmission losses. However, output power generated from natural energy, such as wind power, photovoltaic’s, etc., which is distributed generation, is influenced by meteorological conditions. Therefore, when the distributed generation increases by conventional control techniques, it is expected that the voltage change of each node becomes a problem. Proposed in this Seminar report is the optimal control of distribution voltage with coordination of distributed installations, such as the load ratio control transformer, step voltage regulator (SVR), shunt capacitor, shunt reactor, and static var compensator. In this research, SVR is assumed to be a model with tap changing where the signal is received from a central control unit. Moreover, the communication infrastructure in the supply of a distribution system is assumed to be widespread. The genetic algorithm is used to determine the operation of this control
Orthogonal frequency division multiplexing (OFDM) is widely used in modern wireless communication system because of its high spectrum efficiency and low susceptibility to multi-path. It has receive rising interest recently and has been proposed for number of communication system, such as wireless local area networks and high data rate wireless transmissions. The principal of OFDM is to divide high rate information bits stream into several parallel low rate data sub streams and used these sub stream to modulate numbers of sub-carriers by Fourier transform techniques. OFDM offers ISI free transmission.
5. Use the function generator to generate a sinusoid of frequency 100 kHz and amplitude 0.1 V. Use the oscilloscope to verify that the amplitude is the correct value for the spectrum analyzer (meaning that the SA sees an amplitude of 0.1V). Now observe the signal power spectrum on the spectrum analyzer. Measure the power level and frequency. Record your measurements in the table on the final page of this lab.
The tapered waveguide structure allows diode pumping at its multimode broad channel end and ensures fundamental-mode laser output at the single-mode channel end, with adiabatic operation achievable through careful design of the interconnecting taper. Linear and parabolic taper shapes are compared. The two types of waveguides expanding to various widths over the same lengths were fabricated on the same Nd:BK7 substrate and characterised with Ti:sapphire pumping. The linear tapers show superior operation for larger guiding sizes up to taper widths of 250μm, and therefore are more compatible with high-average-power broad-stripe diode pumping. Double-clad planar waveguides, fabricated by direct bonding YAG and sapphire, have features that are very attractive in this work: they are ideally suited to high- power diode bar/stack pumping owing to their high NA (0.46) slab-like geometry; and they are shown to robustly maintain single-mode operation by gain mode selection. Both diode bars and stacks were used to side-pump a 30μm double-clad Nd:YAG waveguide. For diode-bar pumping, an extended cavity was used to control the output spatial mode in the non-guided axis. Multimode output power larger than 10W was obtained from the waveguide with a slope efficiency of 56%, which was reduced to 33% when the external cavity was optimised for beam quality, obtaining
From Eq. (2), it can be seen that the high PAPR can be reduced either by reducing the maximum signal power or by increasing the averagepower. In reality, reducing the maximum signal power is used in most cases because increasing the averagepower causes more interference. Several approaches have been proposed to reduce the high PAPR and they can be divided into three main categories . The first approach relies on coding technique which uses a special coding, i.e. Forward Error Correct (FEC), to reduce the large PAPR. This approach does not cause interference but it increases the complexity of the transmitter and decreases the transmission rate. The second approach is the signal distortion technique, which simply reduces the signal amplitude by distorting the signal. Clipping technique and peak windowing, for instance, belong to this approach. The last one is based on scrambling each OFDM symbol with different scrambling sequences and then selecting the sequence that gives the smallest PAPR. Although there are many techniques for reducing high PAPR, all these approaches have some corresponding disadvantages, such as signal distortion and complexity of the implementation. These approaches also cannot guarantee that the signal after processing can avoid PA nonlinear distortion.
OFDM is being considered as the modulation scheme. The objective of this survey is to provide the readers and practitioners in the industry with a broader understanding of the high peak-to-averagepower ratio (PAPR) problem in orthogonal frequency division multiplexing (OFDM) systems and generate taxonomy of the available solutions to mitigate the problem. OFDM (Orthogonal Frequency Division Multiplexing) is generally preferred for high data rate transmission in digital communication. OFDM system has a major shortcoming of high peak to averagepower ratio (PAPR) value. The rapid growth in multimedia-based applications has triggered an insatiable thirst for high data rates and hence increased demand on OFDM-based wireless systems that can support high data rates and high mobility. As the data rates and mobility supported by the OFDM system increase, the number of subcarriers also increases, which in turn leads to high PAPR. As future OFDM-based systems may push the number of subcarriers up to meet the higher data rates and mobility demands, there will be also a need to mitigate the high PAPR that arises, which will likely spur new research activities. This paper explains different PAPR reduction techniques and discusses the advantages and limitations of several important PAPR reduction techniques such as Coding, Partial Transmit Sequence, Clipping, Selective Mapping, Tone Reservation, Tone Injection, and Active Constellation Extension. It also presents a comparison of the various techniques based on theoretical results.
• We consider the peak transmit power, the budget power and the total energy constraints for IoT devices. Fur- ther based on the large-scale CSI condition, a whole- trajectory-oriented optimization problem is formulated to maximize the data collection efficiency by optimizing the transmission duration time of all devices, as well as their transmit power. Notably, in this work all the communication parameters are designed in a predefined manner, i.e., prior to the UAV flight. By adopting the random matrix theory, the maxmin optimization theory, as well as the convex optimization tools, we propose an efficient algorithm to solve the problem. Based on that, we also discuss the impact of UAV’s deploying parameters on system performance.
OFDM (Orthogonal Frequency Division Multiplexing) has been raised a new modulation technique. Due to its advantages in multipath fading channel e.g. robust against ISI, ICI and some other advantages like best QoS for multiple users, efficient usage of bandwidth it is suggested to be the modulation technique for next generation 4G networks e.g. LTE. But along with all its advantages there are some disadvantages also e.g. High PAPR (Peak to AveragePower Ratio) at the transmitter end and BER (Bit Error Rate) at the receiving end. Since OFDM is only used in the downlink of 4G networks. To reduce the problems of OFDM some techniques e.g. SLM, PTS, Clipping, Coding, & Pre-coding etc are suggested but none of them is reduce the PAPR and BER to an acceptable value. This Paper will discuss some techniques of PAPR & BER reduction, and their advantages and disadvantages in detail.
The STM32F103C8T6 performance line family incorporates the high performance ARM Cortex™- M3 32-bit RISC core operating at a 72 MHz frequency, high speed embedded memories and an extensive range of enhanced I/O and peripherals connected to two APB buses. The STM32F103C8T6 medium-density performance line family operates from a 2.0 to 3.6 V power supply. It is available in both the –40 to +85 °C temperature range and the –40 to +105 °C extended temperature range. A comprehensive set of power- saving mode allows the design of low-power applications.
Abstract– This work is looking for a new physical layer of a multicarrier wireless communication system to be implemented in low complexity way, resorting to a suitable fast transform. The work presents and assesses a scheme based on Discrete Trigonometric Transform with an appending symmetric redundancy either in each or multiple consecutive transformed blocks. A receiver front-end filter is proposed to enforce a whole symmetry in the channel impulse response. Further, a bank of one tap filter per sub- carrier is applied as an equalizer in the transform domain. The behavior of the transceiver is studied in the context of the practical impairments such as fading channel, carrier frequency offset (CFO), and narrowband interference. Moreover, the performance is evaluated in contrast with the state-of-the-art method by means of computer simulations. It has been found that the new scheme improves the robustness and the reliability of the communication signal, and records lower peak to averagepower ratio. The study demonstrates that the front-end matched filter effectively performs frequency synchronization to compensate the CFO frequency offset in the received signal.
stations in this system: CCR and one of non- constraint resource named, NC. Demands arrive to the CCR in a Poisson manner with rate demands/hour. Operations at CCR are done independently with exponential operation times, with mean operation time equal to 1 . The work in the NC is interruptible, allowing a worker in the NC to switch to CCR with little delay or lost productivity. The switch from NC to CCR would occur at those moments when the queue of waiting demands in the CCR becomes “too long”. The reverse switch from the CCR to the NC occurs once the number of demands is sufficiently small. For the NC, we must have sufficiently many workers there (on average) so that the NC due to switching workers stays non-constraint. The goal is find thresholds for switching workers between CCR and NC to increase the output of system. 2.2 Notation The following notations are made for the remainder of this paper in order to make the analysis mathematical.
Orthogonal frequency division multiplexing system is considered one of the important technologies, which used in the high-speed wireless communication system. Although, it has many advantages such as high data rate, ability to combat the multipath fading channels and more efficiency for utilization the bandwidth, the same time has some obstacles also. The peak to averagepower ratio considers the major drawback of OFDM system. In the OFDM system, some instantaneous power outputs increase greatly and become so far greater than the mean power of the system with the condition the phases of these carriers are same, this is defined the high PAPR, which causes running the system devices in the nonlinear region leading deterioration in performance of OFDM system. In this paper, we present the characteristics of PAPR with two cases normal and special cases (when the OFDM signal has large consistency samples). At the same time, the parameters that influence to PAPR performance have been analyzed and simulated by using MATLAB software. The simulation results show the numbers of sub-carriers, modulation schemes and oversampling rate influence to PAPR performance. It is observed that the numbers of sub-carrier have the significant influence on PAPR performance. However, oversampling rate and modulation schemes have a small effect on PAPR performance.
In this paper, we consider a dual-hop satellite relay system operating at Ka band and propose a secure beamforming scheme to minimize the transmit power at satellite under the constraint of quality- of-service (QoS) and secrecy performance requirement of the destination. Speciﬁcally, we use the method of mixed penalty function to obtain the analytical optimal BF weight vector, which is diﬀerent from the previous works, such as , where semi-deﬁnite programming (SDP) is utilized and only numerical results are obtained. Finally, simulation results verify the superiority of the proposed algorithm.
ABSTRACT: The main aim of this project is reduce the PAPR of transmitted OFDM signals, improve the transmitted image quality & The SPIHT coder is chosen as the source coding technique due to its flexibility of code rate and simplicity of designing optimal system. Trigonometric transforms are used in this scheme for improving the performance of the OFDM system and reducing the Peak-to-AveragePower Ratio (PAPR) of OFDM signal. The PAPR is a major drawback of multicarrier transmission system such as OFDM. The Set Partitioning In Hierarchical Tress (SPIHT) algorithm is used for source coding of the images to be transmitted.